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physica status solidi (c)    [3 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1862-6351 - ISSN (Online) 1610-1642
     Published by John Wiley and Sons Homepage  [1594 journals]   [SJR: 0.397]   [H-I: 27]
  • Luminance and current distribution of hybrid circular GaN‐based
           resonant‐cavity light‐emitting diodes with lateral current
           injection on the n‐ and p‐side
    • Authors: Thorsten Passow; Michael Kunzer, Paul Börner, Wilfried Pletschen, Klaus Köhler, Joachim Wagner
      Pages: n/a - n/a
      Abstract: Resonant‐cavity light‐emitting diodes emitting at around 400 nm based on an undoped bottom AlInN/GaN distributed Bragg reflector (DBR) and a top dielectric SiO2/ZrO2 DBR with circular emitting apertures of diameters ranging from 5 to 200 µm are demonstrated. The current distribution is investigated by luminance distribution imaging and three‐dimensional device simulations for different current densities. The current distribution exhibits a maximum in the aperture centre or is homogeneous up to an aperture diameter of 50 µm independent of the current density. A minimum occurs in the aperture centre for larger diameters increasing with increasing diameter and current density. The current distribution improves with larger n‐GaN thickness and higher contact resistance between the transparent In2O3:Sn (ITO) electrode and the p‐GaN contact layer. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:18.106314-05:
      DOI: 10.1002/pssc.201300417
  • A dual‐character InGaN/GaN multiple quantum well device for
           electroluminescence and photovoltaic absorption of near‐mutually
           exclusive wavelengths
    • Authors: Jian‐Wei Ho; Surani‐bin Dolmanan, Chuan Beng Tay, Qixun Wee, Andrew A. O. Tay, Soo‐Jin Chua
      Pages: n/a - n/a
      Abstract: We report on the dual‐character of an InGaN/GaN multiple quantum well (MQW) device structure epitaxially grown by MOCVD on a 150 mm Si‐on‐insulator (SOI) wafer. The fabricated mesa device exhibits photovoltaic (PV) response mainly for λ < 500 nm and strong electroluminescence (EL) for 470 nm < λ < 750 nm with a major amber component about 580 nm < λ < 620 nm. Multiple, high amplitude oscillations are observed in the luminescence spectra and verified by theoretical modelling as strong Fabry‐Perot interference effects. HR‐XRD ω ‐2θ (0002) scan estimates a mean In composition of ∼22% in the MQWs, consistent with the PV absorption edge and weak photoluminescence (PL) emission when excited by a 518 nm laser at 20K. Under 405 nm laser excitation at low temperatures, PL emission for 600 nm < λ < 740 nm is greatly enhanced. Asymmetric broadening of the spectral peak to 570 nm < λ < 740 nm occurs when the excitation energy is increased with a 325 nm laser, and is attributed to radiative transitions associated with MQW interface defects. This is supported by the (105) reciprocal space map which shows slight relaxation of the MQWs. The strong but broad long‐wavelength emission, is ascribed to the MQW interface defects and highly recombinative In‐rich clusters. These hardly contribute to PV response and are responsible for the protracted Stokes shift that constitutes the apparent near‐mutual exclusion of EL and PV absorption wavelengths. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:17.348365-05:
      DOI: 10.1002/pssc.201300420
  • Whispering gallery modes in GaN microdisks, microrods and nanorods grown
           by MOVPE
    • Authors: Christian Tessarek; Martin Heilmann, Silke Christiansen
      Pages: n/a - n/a
      Abstract: Self‐assembled GaN microdisks, micro‐ and nanorods were grown by a mask‐free and self‐catalyzed metal‐organic vapor phase epitaxy method. The morphology of the structures is analyzed by scanning electron microscopy. All rods have a hexagonal shape with smooth sidewall facets and sharp edges. Depending on the deposition of a GaN nucleation layer prior to growth of GaN rod structures the diameter of the rods can be adjusted. Nanorods with diameters down to 400 nm as well as microrods and disks with diameters up to 5 µm can be achieved. The optical properties of the rods are investigated utilizing a combined scanning electron microscopy and cathodoluminescence system. Electron beam excitiation of GaN rods leads to a typical GaN spectrum showing GaN near band edge emission at 369 nm and broad yellow defect luminescence at 560 nm. Enhanced emission is located at the top of the rod. By fixing the focussed electron beam at a sidewall position of a single GaN rod, whispering gallery modes are observed in the cathodoluminescence spectrum. Depending on the diameter of the micro‐/nanorods the spectral position of the modes as well as the spectral distance between the modes can be adjusted. Quality factors up to 475 are measured. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:16.373098-05:
      DOI: 10.1002/pssc.201300421
  • Appropriate fabrication procedure for InAlN
           metal‐oxide‐semiconductor structures with
           atomic‐layer‐deposited Al2O3
    • Authors: Masahito Chiba; Takuma Nakano, Masamichi Akazawa
      Pages: n/a - n/a
      Abstract: The fabrication‐procedure dependence of the electrical properties of the InAlN metal‐oxide‐semiconductor (MOS) structure with Al2O3 formed by atomic layer deposition (ALD) was investigated. When the ALD Al2O3/InAlN interface was formed after ohmic‐contact annealing in nitrogen without the use of a cap layer, the electrical characteristics were poor with a small capacitance change in the capacitance‐voltage (C‐V) curve. X‐ray photoelectron spectroscopy (XPS) study indicated that the bare InAlN surface was oxidized during capless annealing presumably owing to the trace contamination in the furnace. High‐temperature ohmic‐contact annealing after Al2O3/InAlN interface formation, using the Al2O3 layer as a cap layer for surface protection, did not improve the interface properties, resulting in the interface state density Dit in the range of 1013 cm–2eV–1; this was highly likely related to the crystallization of Al2O3. When a SiNx layer was used as the cap layer during ohmic‐contact annealing prior to ALD, greatly improved characteristics of the MOS diode were achieved, indicating that Dit was suppressed to be in the range of 1012 cm–2eV‐1 near the conduction band. The obtained results indicate that an appropriate fabrication procedure leads to an improvement of the Al2O3/InAlN interface properties. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:15.44499-05:0
      DOI: 10.1002/pssc.201300423
  • Short period polar and nonpolar m InN/n GaN superlattices
    • Authors: I. Gorczyca; T. Suski, G. Staszczak, X. Q. Wang, N. E. Christensen, A. Svane, E. Dimakis, T. D. Moustakas
      Pages: n/a - n/a
      Abstract: The electronic structures of nonpolar short‐period InN/GaN superlattices grown in the wurtzite a ‐direction, have been calculated and compared to earlier calculations for polar superlattices (grown in the c‐direction). For the nonpolar superlattices it is found that the calculated band gaps and their pressure coefficients are quite similar to those of bulk InGaN alloys with an equivalent In/Ga composition ratio. Also, they are much closer than the values calculated for polar superlattices to the photolu‐minescence emission energies and their pressure coefficients measured on polar structures. Possible explanations of the observed phenomena are suggested and discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:14.447177-05:
      DOI: 10.1002/pssc.201300424
  • Epitaxial rare earth oxide and nitride buffers for GaN growth on Si
    • Authors: Rytis Dargis; Robin Smith, F. Erdem Arkun, Andrew Clark
      Pages: n/a - n/a
      Abstract: The erbium oxide and nitride layers were grown as a buffer for GaN on Si(111). Engineering of the nucleation layer on the oxide plays a crucial role in the quality of the GaN layer. The intermediate erbium nitride layer with lattice constant between that of GaN and Si additionally reduces the semiconductor layer lattice mismatch to the substrate and prevents direct bonding of gallium atoms with the oxygen of the rare‐earth oxide. The crystal structure and surface morphology of epitaxial single crystal gallium nitride layer grown on the buffer improves with the semiconductor layer thickness. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:13.531118-05:
      DOI: 10.1002/pssc.201300426
  • Structural analysis of N‐polar AlN layers grown on Si (111)
           substrates by high resolution X‐ray diffraction
    • Authors: Mahesh Pandikunta; Oleg Ledyaev, Vladimir Kuryatkov, Sergey A. Nikishin
      Pages: n/a - n/a
      Abstract: Crack‐free high quality N‐polar AlN epitaxial layers were grown on Si (111) substrates by plasma‐assisted molecular beam epitaxy in the temperature range of 780–880 °C. The streaky 1×3 reflection high energy electron diffraction pattern was observed at room temperature for all AlN samples indicating N‐polarity of epilayers. The polarity of samples was also confirmed by KOH etching studies. Structural properties of as‐grown samples were carried out by high resolution X‐ray diffraction, scanning electron microscopy, and atomic force microscopy. The Williamson‐Hall plots of the rocking curves widths were employed in order to study the mosaicity, dislocation density, and level of stress as a function of growth temperature. The 250 nm thick AlN sample grown at 830 °C yields the best crystalline quality, smooth surface morphology, and smallest root mean square roughness. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:12.56591-05:0
      DOI: 10.1002/pssc.201300428
  • Gallium nitride laser diodes with integrated absorber: on the dynamics of
    • Authors: Katarzyna Holc; Gerrit Lükens, Thomas Weig, Klaus Köhler, Joachim Wagner, Ulrich T. Schwarz
      Pages: n/a - n/a
      Abstract: The dynamics of self‐pulsation in monolithic multi segment GaN‐based laser diodes (LDs) with integrated absorber, and operating at 410 nm is investigated. The bias‐dependent modal absorption of the devices is determined by high resolution Hakki‐Paoli gain spectroscopy. Using a streak camera detection system we measure the pulsation frequency, applying bias voltages up to –40 V to the absorber section of the multi segment LD. Under moderate reverse voltages, to approximately –15 V, the absorption features a quadratic dependence on the bias voltage with a clear minimum corresponding to the flat band conditions. In this regime we observe stabilized relaxation oscillations, with a pulse repetition rate which depends only on the current in the gain section, but not on the reverse bias in the absorber section. At higher reverse voltages a linear increase of the modal absorption is observed. There, the devices switch to the self‐Q‐switching regime which exhibits a linear decrease of the pulsation frequency with increasing reverse bias. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:11.583168-05:
      DOI: 10.1002/pssc.201300429
  • Effect of nano‐column properties on self‐separation of thick
           GaN layers grown by HVPE
    • Authors: V. Nikolaev; A. Golovatenko, M. Mynbaeva, I. Nikitina, N. Seredova, A. Pechnikov, V. Bougrov, M. Odnobludov
      Pages: n/a - n/a
      Abstract: The implementation of control over self‐separation of thick GaN flayers grown by Hydride Vapor‐Phase Epitaxy (HVPE) on Metal‐Organic Chemical Vapor Deposition (MOCVD)‐grown templates with patterned nano‐column interlayer is reported. Both numerical simulation and experimental data show that separation of thick HVPE layers is provided by non‐uniform redistribution of the growth stress. It is shown that the geometrical parameters of the nano‐column structure such as fill factor and shape of the columns are most critical for self‐separation effect. By adjusting the nano‐column pattern, successful self‐separation of thick HVPE layers from 2‐inch structured MOCVD GaN/sapphire substrate was demonstrated. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:10.724718-05:
      DOI: 10.1002/pssc.201300432
  • Nitrogen ion implantation isolation technology for normally‐off GaN
           MISFETs on p‐GaN substrate
    • Authors: Hayao Kasai; Hiroki Ogawa, Tomoaki Nishimura, Tohru Nakamura
      Pages: n/a - n/a
      Abstract: Nitrogen ion implanted isolation technology to prevent leakage current between adjacent devices fabricated on p‐GaN layers on sapphire substrate is described. Leakage current due to n‐type inversion layers caused by Fermi level pinning at the p‐GaN surface and buffer layers between sapphire substrate and GaN epitaxial layer is greatly reduced. With nitrogen ion implanted isolation technology of this study, leakage current between adjacent devices reduced five orders of magnitude compared to that without isolation layers. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-24T06:10:09.921125-05:
      DOI: 10.1002/pssc.201300436
  • Role of ZnO nanoparticle‐layers in enhancement of the performance of
           organic light‐emitting diodes on plastics
    • Authors: Kiyeol Kwak; Kyoungah Cho, Sangsig Kim
      Pages: n/a - n/a
      Abstract: We investigate roles of ZnO nanoparticle (NP)‐layers in the enhancement of the emission from organic light‐emitting diodes (OLEDs) with amorphous ZnO‐doped In2O3 (a ‐IZO)/poly(3,4‐ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/poly[(9,9‐di‐n ‐octylfluorenyl‐2,7‐diyl)‐alt ‐(benzo[2,1,3]thiadiazol‐4,8‐diyl)] (F8BT)/ZnO NP‐layer/LiF/Al structure on plastic substrates. Compared to a Reference OLED without any ZnO NP‐layer, the electroluminescence peak intensity of the OLED employing the thermally‐annealed ZnO NP‐layer spin‐coated one time is remarkably enhanced by ∼283% at a wavelength of ∼535 nm owing to the effective hole blocking and good electron transporting properties of the ZnO NP‐layer between the organic emissive layer (EML) and the electron injection layer (EIL). This enhancement is associated with the high junction potential barrier between the highest occupied molecular orbital level of the F8BT and the valence band level of the ZnO NP‐layer, which contributes to the effective hole blocking. Our study clearly demonstrates that the ZnO NP‐layer sandwiched between the EML and the EIL is a promising electron transport layer as well as an efficient hole blocking layer and enhances the light emission of OLEDs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-23T08:40:10.594754-05:
      DOI: 10.1002/pssc.201300387
  • Electrical modeling of the GaAs/InP wafer bonded heterojunction
    • Authors: Xavier Blot; Pascal Scheiblin, Hubert Moriceau, William Van Den Daele, Christophe Lecouvey, Daniel Delprat, Aurélie Tauzin, Charlotte Drazek, Eric Guiot
      Pages: n/a - n/a
      Abstract: The electrical behavior of wafer bonded heterojunctions is usually modeled with the assumption of a pure thermionic conduction at the interface. In this paper, we study the case of highly doped bonded wafers using a Technology Computer Aided Designed (TCAD) modeling approach. Several plausible options of interface including fixed surface charges, interface states densities or a defective interface layer, are discussed and compared with current‐voltage measurements. Considering both thermionic and tunnel transport through the interface, we show how the ratio of the competing transport mechanisms depends on the shape of the interfacial energy barrier. Finally, the simulation accurately predicts the effect of the operating temperature on current‐voltage characteristics, thanks to a process‐compliant description of the direct bonded heterojunction. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-23T08:40:09.326162-05:
      DOI: 10.1002/pssc.201300386
  • Structures with two‐dimensional distributed feedback for a laser
           realization on Si:Er basis
    • Authors: Margarita Stepikhova; Vladimir Baryshev, Naum Ginzburg, Sergey Vdovichev, Boris Gribkov, Alexander Klimov, Zachary Krasilnik
      Pages: n/a - n/a
      Abstract: Using 2D distributed feedback (DFB) exploiting 2D Bragg resonators for a Si:Er lasers is suggested. Self excitation conditions are defined analytically. Numerical simulation of the nonlinear dynamics demonstrates that 2D DFB can provide synchronization of radiation for wide active media. A test laser‐like Si/SOI structure is fabricated and described. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-23T08:40:08.278369-05:
      DOI: 10.1002/pssc.201300384
  • Analysis of carrier injection in Si nanoparticle‐SiOx film based MOS
    • Authors: E. Jacques; L. Pichon, C. Labbe, L. Khomenkova, F. Gourbilleau
      Pages: n/a - n/a
      Abstract: The electrical properties of silicon rich oxide (SRO) layers integrated in metal‐oxide‐semiconductor device are analysed. The layers are deposited using the magnetron co‐sputtering of a pure SiO2 and Si targets under a pure argon plasma. Each SRO layer embedding silicon nanoparticles (Si‐np‐SiOx) was subsequently submitted to an optimized annealing treatment. Three types of Al/Si‐np‐SiOx/p‐Si devices are fabricated with different incorporated silicon excesses (9, 11, or 16 at.%) in the active layer. Analysis of static electrical properties of the devices showed a semi‐resistive behaviour for each device. Carrier injection into the SiOx matrix in terms of Poole‐Frenkel and Fowler‐Nordheim mechanisms is analysed in relation with the incorporated silicon excess. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-23T08:40:07.039595-05:
      DOI: 10.1002/pssc.201300379
  • Measurement of electric field enhanced optical absorption in hydrogenated
           amorphous silicon
    • Authors: Matija Pirc; Jože Furlan, Andrej Levstek, Marko Topič
      Pages: n/a - n/a
      Abstract: Optical properties of amorphous semiconductors are influenced by applied or built‐in electric fields. Measurements of the optical absorption change of device grade intrinsic hydrogenated amorphous silicon were performed indirectly by measuring the optical transmission of the samples with and without an applied DC electric field. Effects of ambient temperature changes were limited by strict control of the ambient temperature. Temperature effects caused by self‐heating of the samples were compensated in two different ways to ensure the validity of the results. The influence of temperature change on optical absorption was identified and compensated by the analysis of measurements of multiple samples with different levels of power dissipation brought about by sample conductivity variations. The second method of temperature compensation consisted of determining the temperature change of each sample during the measurements, modelling absorption coefficient change caused by the temperature change and by subtracting the calculated absorption change caused by the temperature change from the measured absorption change. Results of both methods of temperature compensation are in good agreement. The obtained results are also in agreement with the results of other researchers up to photon energies slightly above the mobility edge, where our measurements exhibit a slightly different dependency on photon energy than previously published measurements. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-23T08:40:06.009745-05:
      DOI: 10.1002/pssc.201300176
  • Evaluation of an InAlN/AlN/GaN HEMT with Ta‐based ohmic contacts and
           PECVD SiN passivation
    • Authors: Anna Malmros; Piero Gamarra, Mattias Thorsell, Marie‐Antoinette di Forte‐Poisson, Cedric Lacam, Maurice Tordjman, Raphaël Aubry, Herbert Zirath, Niklas Rorsman
      Pages: n/a - n/a
      Abstract: An InAlN/AlN/GaN HEMT with Au‐free Ta‐based ohmic contacts and a high‐quality PECVD SiN pas‐sivation is reported. The ohmic contacts were annealed at 550 °C, resulting in a contact resistance of 0.64 Ωmm. The gate length was 50 nm. The device performance and the process were evaluated by performing DC‐, pulsed IV‐, RF‐, and load‐pull measurements. It was observed that current slump was effectively mitigated by the passivation layer. The DC channel current density increased by 71 % to 1170 mA/mm at the knee of the IV curve, and the transconductance increased from 382 to 477 mS/mm after passivation. At the same time the gate leakage increased, and the extrinsic fmax decreased from 207 to 140 GHz. Output powers of 4.1 and 3.5 W/mm were measured after passivation at 31 and 40 GHz, respectively. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-22T09:40:14.439623-05:
      DOI: 10.1002/pssc.201300320
  • X‐ray diffraction analysis of structural defects in a‐plane
           GaN grown on r‐plane sapphire by MOCVD
    • Authors: Qing S. Paduano; David W. Weyburne
      Pages: n/a - n/a
      Abstract: In this work, we demonstrate the use of X‐ray diffraction for analyzing structural imperfections in a‐plane GaN grown on r‐plane sapphire. Although there are only two (hh 0) planes accessible under symmetric diffraction, there are an adequate number of diffraction planes accessible under the quasi‐symmetric configuration to enable analysis of rocking curves that are not influenced by basal‐plane stacking faults. By measuring diffraction profiles for a series of symmetric and asymmetric crystal planes, the broadening terms were separated using extrapolation methods based on their geometric dependence. Individual broadening factors can then be correlated to the relative contribution of different structural defects, including threading dislocations, lateral coherence length, and basal plane stacking faults. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-22T09:40:13.61821-05:0
      DOI: 10.1002/pssc.201300325
  • Photoluminescence of m‐plane GaN grown on m‐plane sapphire by
    • Authors: Qing S. Paduano; David W. Weyburne, David C. Look
      Pages: n/a - n/a
      Abstract: The photoluminescence of m‐plane GaN grown on m‐plane sapphire substrate by MOCVD is reported. The defect related emissions with temperature and excitation power dependence are detailed. In addition to the near band‐edge emission (at ∼3.472 eV), two major defect‐related bands (D1∼3.43 eV and D2∼3.34 eV) are dominant in the low temperature spectra. The D1 emission exhibits thermal quenching with two activation energies (8 and 30 meV), similar to that of a‐plane GaN grown on r‐plane sapphire. The D2 band was found to consist of a complex overlap of multiple emissions. By fitting the asymmetric band using multiple Gaussian functions, the extracted emission at ∼3.34 eV was shown to have thermal activation energy ∼17–20 meV. This emission exhibits different behavior from that of D2 in a‐plane GaN in temperature and excitation power dependency, indicating the possible involvement of different defects due to the changes in growth characteristics. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-22T09:40:12.26137-05:0
      DOI: 10.1002/pssc.201300328
  • Assessment of factors limiting conversion efficiency of
           single‐junction III‐nitride solar cells
    • Authors: Kirill A. Bulashevich; Sergey Yu. Karpov
      Pages: n/a - n/a
      Abstract: Using simulations, we have identify the major factors controlling the conversion efficiency of single‐junction n‐GaN/i‐InxGa1‐xN/p‐GaN solar cells, including absorptivity of solar radiation, heterostructure polarity, composition of the InGaN active layer, and non‐radiative life‐times of generated electrons and holes. The interplay of these factors, their hierarchy, and the possible effect of stress relaxation in InGaN on the conversion efficiency are discussed in terms of modeling. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-22T09:40:11.342382-05:
      DOI: 10.1002/pssc.201300389
  • (20‐21) MOVPE and HVPE GaN grown on 2″ patterned sapphire
    • Authors: Tobias Meisch; Maryam Alimoradi‐Jazi, Martin Klein, Ferdinand Scholz
      Pages: n/a - n/a
      Abstract: (20‐21) GaN was grown on (22‐43) patterned sapphire substrates by MOVPE and subsequently overgrown in a HVPE growth step. By using fairly c‐plane growth conditions and adjusting the reactor temperature of the particular layers, GaN stripes free of any parasitic islands were grown by MOVPE. X‐ray measurements confirmed a very promising crystal quality. It turned out, that the stripes are formed by (10‐11) and (0001) facets, which seems to be the most stable facets during growth. Via HVPE overgrowth, the single stripes coalesce and form a flaky surface. A fairly high growth rate of about 142 μm per hour was achieved. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-22T09:40:10.345998-05:
      DOI: 10.1002/pssc.201300396
  • Cover Picture: Phys. Status Solidi C 1/2014
    • Pages: n/a - n/a
      Abstract: With the transition from planar to three‐dimensional device architectures such as FinFets, TFETs and nanowires, new metrology approaches are required to characterize the 3D‐dopant and carrier distributions precisely, as their position‐ing relative to gate edges, 3D‐distribution, conformality and absolute concentration determine the device performance in great detail. As discussed in the paper of Vandervorst et al. on pp. 121–129, concepts like atomprobe tomography, SSRM and 1.5 D SIMS all contribute to resolving this metro‐logy challenge, be it with varying degrees in spatial resolu‐tion, information content and ease applicability.
      PubDate: 2014-01-21T03:58:49.160696-05:
      DOI: 10.1002/pssc.201470031
  • Issue Information: Phys. Status Solidi C 1/2014
    • Pages: n/a - n/a
      PubDate: 2014-01-21T03:58:46.62507-05:0
      DOI: 10.1002/pssc.201470032
  • Erratum: Growth of GaAs nanowires on Si substrate by molecular beam
           epitaxy under alternating supply
    • Authors: R. Kizu; M. Yamaguchi, H. Amano
      Pages: n/a - n/a
      Abstract: Due to a technical mistake, Figures 1 and 3 in this paper [1] were displayed erroneously. Please find here the correct versions of these figures.
      PubDate: 2014-01-02T06:10:24.935252-05:
      DOI: 10.1002/pssc.201360002
  • Excellence – energy – ethics
    • Authors: Stefan Hildebrandt; Sabine Bahrs
      Pages: 1 - 2
      Abstract: Dear pss readers, As the previous year approached its end, news on three excellent prize winnings and nominations of pss authors and editors reached us: Gerhard Abstreiter of TU Munich will receive the Stern–Gerlach Medal 2014, the highest prize of the German Physical Society for experimental physics, honoring his work on low‐dimensional electron systems in semiconductor hetero‐ and nanostructures. His Review@RRL on InGaAs nanowires on silicon is opening the 2014 volume of pss (RRL) [1]. It is a welcome addition to our recent successful Focus Issue on Semiconductor Nanowires [2]. Our long‐term Editorial Advisory Board member, Wiley author and Guest Editor, Rainer Waser of RWTH Aachen and Research Centre Jülich, is one of the 11 winners of the highly prestigious Leibniz Prize for his outstanding research on nanoelectronics, especially oxides, ferroelectrics and resistive switching [3, 4]. Last but not least, one of the three nominated teams for the German Future Prize has been led by Wolfgang Schnick, LMU Munich, and Peter J. Schmidt, Philips Lumileds Aachen. Their groundbreaking work on new phosphor materials in white light emitting diodes (LEDs) for solid‐state lighting [5] goes back to a highly‐cited pss (a) article from 2005 [6] (see figure). The technology is now being commercialized and expected to enable energy savings on a grand scale in the coming years. Speaking of energy, research results related to this global challenge have been important throughout the year, touching areas such as thermoelectrics [7], efficiency of organic LEDs [8] and photovoltaics [9]. The latter field is even better represented since the recent introduction of our section rrl solar, covering solar cell materials or device development and characterization (see Editorial [10]). The full‐paper sister journals pss (a) and (b) presented an unprecedented number of high‐profile special issues in 2013 [11–15]. With heartfelt gratitude we look back onto fruitful collaboration with highly engaged guest editors, who helped bring to light issues such as the “Advanced Concepts for Silicon Based Photovoltaics” [11], the “Quantum Criticality and Novel Phases” [12], the “Disorder in Order: A special issue on amorphous materials” [13], the “Substrate Interactions in Heterogeneous Catalysis” [14], and the “Quantum Transport at the Molecular Scale” [15] among other interesting topical issues and sections. Both contributors and fine articles are too numerous to do justice to all of them here. We must restrict ourselves to a general invitation to browse this content, only hinting a few possible starting points, such as topological insulators [16], molecular electronics [17] and quantum phase transitions [18]. Artist's view of two‐phosphor converted white light LED (from [6]) On the editorial and technical side, we look back on a busy year dominated by the globalization of the Berlin Editorial Office home base [19], with Wiley colleagues in Weinheim, Beijing and Hoboken now contributing to our joint success, and by the introduction of Editorial Manager (EM). This state‐of‐the‐art online submission, reviewing and editorial handling system provides much better, more flexible and very reliable service to our thousands of authors and helpful reviewers. As every year, we extend our sincere thanks to our ever‐growing and extremely supportive community of anonymous peers who have decisively contributed to keep our editorial standards up or even raise them further. Adding to strict peer review, the installation of EM was accompanied by the introduction of iThenticate, an online tool which checks a submitted manuscript against published literature (from publishers participating in the CrossCheck initiative) and other internet sources. This helps us to prevent plagiarism, i.e. unauthorized and unmarked copying of text written by others, as well as significant text recycling from authors' previous own articles which we, unfortunately, sometimes encounter among the manuscripts submitted for consideration. Such tendencies are clearly discouraged by the Editors as documented in the various sources informing about our editorial and ethical guidelines [20, 21], and we are glad to have a tool at our disposition that assists us and the reviewers in ensuring these standards. In result of all the above‐mentioned efforts we are proud to report that visibility and impact of pss publications have further increased during the past year. Please be invited to follow pss content on Wiley Online Library (WOL), our table of contents alerts and RSS feeds as well as indexing services. As a final outlook into the New Year, early 2014 will see the launch of Anywhere Article, a new user interface to WOL providing better access to our content especially for users of mobile devices. So watch out for this exciting new feature! With best wishes for a successful and healthy 2014, on behalf of all pss colleagues Stefan Hildebrandt and Sabine Bahrs
      PubDate: 2014-01-21T03:58:49.227075-05:
      DOI: 10.1002/pssc.201470033
  • Contents: Phys. Status Solidi C 1/2014
    • Pages: 3 - 6
      PubDate: 2014-01-21T03:58:42.606054-05:
      DOI: 10.1002/pssc.201470034
  • Advanced Extra Functionality CMOS‐based Devices
    • Authors: Fuccio Cristiano; Peter Pichler, Clément Tavernier, Wolfgang Windl
      Pages: 7 - 8
      Abstract: This volume contains the proceedings of the E‐MRS 2013 symposium K, entitled “Physics and Technology of Advanced Extra Functionality CMOS‐based Devices” that was held from May 27th to May 31st 2013 in Strasbourg, France. In total, 93 papers were presented, including 13 invited presentations, 51 contributed oral presentations and 29 poster presentations. Our symposium provided an open forum for the presentation of original experimental and theoretical studies that contribute to the physical understanding of phenomena related to new materials and processes for devices that add extra functionality to conventional CMOS backbone processes. Going from core CMOS technology to CMOS derivatives implies a change of paradigm in R & D. While core CMOS technology aims at improved performance, particularly switching speed, it is mandatory for CMOS derivatives to find a trade‐off between the traditional view of device ‘performance’ (switching speed,...) and increasingly critical low power consumption requirements (calling for improved control of leakage currents, standby power consumption, dark currents…). The high‐quality symposium contributions and the inspiring discussions in the various sessions all contributed to the symposium success, particularly thanks to the invited speakers who provided excellent reviews of their recent works and of the state‐of‐the‐art in their respective fields. The exciting opportunities and challenges associated to some specific More‐than‐Moore applications, such as CMOS imagers and healthcare applications were presented in the opening session by François Roy from STMicroelectronics and Sywert Brongers‐ma from Holst Centre/IMEC. Throughout the symposium, reviews of the main challenges related to most of the building blocks of advanced CMOS‐based devices were given in terms of both fundamental material studies and/or technology optimisation. These included substrate engineering (Eugene Fitzgerald, MIT), source/drain doping (Benjamin Colombeau, Applied Materials), dopant diffusion (Hartmut Bracht, Univ. Münster), source/drain silicide fabrication (Dominique Mangelinck, IM2NP‐CNRS) and high‐k gate stacks (Ramamurthy Ramprasad, Univ. of Connecticut). Physical modelling and simulation issues (from ab‐initio to continuum TCAD) were discussed during three dedicated sessions brightly introduced by Matthias Posselt from HZDR (solid phase recrystallization), Andreas Schenk from ETH Zurich (leakage current modelling) and Christoph Zechner from Synopsys (process technology simulations). Finally, recent advances in the field of 3D dopant/carrier characterisation were reported by Wilfried Vandervorst from IMEC, while the use of electrical characterisation to investigate the impact of source/drain defects on leakage currents and advanced MOSFET performances were discussed by Ray Duffy from Tyndall and Mireille Mouis from IMEP‐LAHC‐CNRS. These proceedings contain a selection of 48 manuscripts organised in 5 sections: – Doping and Thermal Processing: Basic Studies and Process Optimization – More‐than‐Moore and Advanced CMOS Devices – Atomistic Modelling and Continuum Simulations – Physical and Electrical Characterization – Silicides and Germanides. We would like to acknowledge the E‐MRS Headquarters staff for its outstanding assistance in organising the symposium as well as Wiley‐VCH staff for helping in the publication of these proceedings. We also wish to thank all contributors and attendees for their active participation to the symposium and all colleagues who reviewed the submitted manuscripts, and contributed in many cases to the improvement of the quality of the published articles. We also wish to congratulate the winners of the best student awards (Fabio Isa from L‐NESS Milano and Ruggero Milazzo from CNR‐IMM‐MATIS Padova) as well as the winners of the best poster awards (Thomas Kreiliger from ETH Zurich and Spyridon Stathopoulos from NTUA University Athens). Finally, the symposium organisers are grateful for the sponsorship provided by several companies and institutions (Ion Beam Services, Semilab, STMicroelectronics, Synopsys, and the CNRS), as well as for the support of the EU commission through the European Project ATEMOX (Advanced Technology Modelling for Extra‐Functionality Devices) that gave rise to the proposal for the organisation of this symposium. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-01-21T03:58:47.066344-05:
      DOI: 10.1002/pssc.201470035
  • NMOS contact resistivity reduction with implants into silicides
    • Authors: K. V. Rao; Fareen Adeni Khaja, Chi‐Nung Ni, Shankar Muthukrishnan, Andrew Darlak, Jianxin Lei, Adam Brand, Naushad Variam
      Pages: n/a - n/a
      Abstract: NMOS contact resistivity (ρc) for NiPtSi was reduced by up to 50% by implanting either Se or P into the silicide film, followed by thermally recrystallizing the silicide and activating the implanted species. The silicide module integration included use of plasma pre‐clean, a thin NiPt film, a low temperature soak anneal (RTP1), and millisecond laser anneals for post‐implant anneals (RTP2 and RTP3). Additionally, experiments with Se implants into TiSi2 achieved 60% reduction in ρc with exclusive use of laser anneals (for both RTP1 and RTP2). The test structures included van der Pauw, transmission line model (TLM) and diodes, all of which are testable after silicidation to extract of silicide phase and sheet resistance (Rs), silicide/SD external resistance (Rext), ρc, and junction breakdown (Vbj). In order to mimic realistic CMOS process flows, contact chain structures testable after metal‐1 were also used to obtain average resistance/contact and extract contact resistivity. The results in this work demonstrated adequate process window, while maintaining junction characteristics without degradation of Rs. Laser anneal steps were key enabler to achieve these results, and were designed to prevent dopant deactivation while minimizing diffusion of SD regions for USJ compatibility for sub‐20 nm CMOS nodes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:20:23.359627-05:
      DOI: 10.1002/pssc.201300381
  • Lattice kinetic Monte Carlo modeling of germanium solid phase epitaxial
    • Authors: J. L. Gomez‐Selles; B. L. Darby, K. S. Jones, I. Martin‐Bragado
      Pages: n/a - n/a
      Abstract: Solid phase epitaxial growth (SPEG) is a common tech¬nique used in the manufacturing processes of MOSFET technology. Even though a relatively broad knowledge is found for silicon, there is a greater uncertainty when it comes to germanium, which importance is arising in the last generation of microelectronic devices. To simu¬late this process, the need of a model which reproduces anisotropic growth and is able to detect and place twin defects becomes relevant, opening the possibility to sim¬ulate the interaction of different crystallographies, as it has been observed to be an important factor for some orientations, justifying by this mechanism experimental results. We present a Lattice Kinetic Monte Carlo (LKMC) model of Ge which is able to give an explanation of the different anisotropy effects in the recrystallization of substrate wafers through a defect formation formalism. An agreement between experimental observations and simulations is found by comparing regrowth velocities for different samples at different anneal conditions with LKMC simulations that consider twin defect formation for specific directions. Different regrowth velocities are found for distinct orientations of a solid phase epitaxial growth process within the annealed sample. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:45.648928-05:
      DOI: 10.1002/pssc.201300159
  • Influence of Poisson equation boundary conditions and quantum corrections
           to carrier concentrations at material interfaces in TCAD process
    • Authors: Alexander Tsibizov; Arsen Terterian, Christoph Zechner
      Pages: n/a - n/a
      Abstract: In TCAD process simulation, the Poisson equation for electrostatic potential is usually solved in silicon and polysilicon regions, assuming a zero normal component of electric field (ZEF) boundary conditions (BCs) at material interfaces. This is correct for a free (or covered only with dielectric) flat surface of silicon, which is typical for 1D SIMS profile simulations. However, it is inaccurate in other important cases, in particular, under the gate of submicron MOS transistors, where more general BCs preserving the continuity of the flux of electric displacement should be applied. In a simulation, the choice of BCs changes the electrostatic potential near material interfaces and, thereby, impacts simulated dopant distributions and transistor characteristics. We introduced such general BCs in Sentaurus Process and applied them to the 2D simulation of CMOS transistors with polysilicon or metal gate. A noticeable (but moderate) increase of simulated threshold voltage in comparison to the ZEF BCs is demonstrated. In addition, the effect of carrier concentration reduction at silicon/dielectric interfaces due to quantum‐mechanical repulsion was introduced into a continuum process simulation using the modified local‐density approximation. This changes the dopant distributions in a nanometre thin layer in semiconductors at both sides of the gate oxide, resulting in a reduced concentration of the main dopant near the interface, which is most pronounced at high dopant concentrations. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:44.823951-05:
      DOI: 10.1002/pssc.201300191
  • On an improved boron segregation calibration from a particularly sensitive
           power MOS process
    • Authors: S. Koffel; A. Burenkov, M. Sekowski, P. Pichler, D. Giubertoni, M. Bersani, M. Knaipp, E. Wachmann, M. Schrems, Y. Yamamoto, D. Bolze
      Pages: n/a - n/a
      Abstract: One of the main issues for the simulation of MOS transistors is the correct prediction of threshold voltages that depend on the active doping profiles in the channel under the gate oxide. Simulating a power MOS process we encountered a situation in which Sentaurus Process with default models failed to predict threshold voltages by as much as 3 V. An in‐depth investigation revealed that the threshold voltage in our pMOS devices is determined by a very special distribution of the doping in the channel that involves both n‐type and p‐type doping which nearly compensate each other. As threshold voltages were found in the simulations to be particularly sensitive to boron segregation, silicon samples were implanted with boron and oxidized in several atmospheres for a variety of process times. The profiles were studied by advanced SIMS methods. Because of the limitations of the SIMS depth resolution, they had to be complemented by electrical measurements on MOS transistors. This combination finally allowed finding a new calibration for the segregation models which allows predicting the electrical characteristics of the transistors in a wide range of experimental conditions. Since the threshold voltage in our transistors turned out to be extremely sensitive to the boron segregation parameters, in contrast to technologies in which only one dopant type prevails, the newly achieved calibration should be superior to previous work. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:43.874759-05:
      DOI: 10.1002/pssc.201300152
  • Application of atomic layer deposited dopant sources for
           ultra‐shallow doping of silicon
    • Authors: Bodo Kalkofen; Akinwumi A. Amusan, Marco Lisker, Edmund P. Burte
      Pages: n/a - n/a
      Abstract: The advanced silicon semiconductor technology requires doping methods for production of ultra‐shallow junctions with sufficiently low sheet resistance. Furthermore, advanced 3‐dimensional topologies may require controlled local doping that cannot be achieved by ionimplantation. Here, the application of the atomic layer deposition (ALD) method for pre‐deposition of dopant sources is presented. Antimony oxide and boron oxide were investigated for such application. Ozone‐based ALD was carried out on silicon wafers by using triethylantimony or tris‐(dimethylamido)borane. Very homogeneous Sb2O5 deposition could be achieved on flat silicon wafers and in trench structures. The thermal stability of antimony oxide layers was investigated by rapid thermal annealing experiments. The layers were not stable above 750 °C. Therefore, this material failed to act as dopant source so far. In contrast, ultra‐shallow boron doping of silicon from ALD grown boron oxide films was successful. However, pure B2O3 films were highly unstable after exposure to ambient air. The boron oxide films could be protected by thin Sb2O5 or Al2O3 films that were in‐situ grown by ALD. Low temperature ALD of Al2O3 at 50 °C from trimethylaluminium (TMA) and ozone was investigated in detail with respect of its protective effect on boron oxide. Interestingly, it was observed that already one ALD cycle of TMA and O3 resulted in significant increase in stability of the boron oxide in air. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:42.982779-05:
      DOI: 10.1002/pssc.201300185
  • Surface evolution of very high dose arsenic implants in silicon formed by
           plasma immersion ion implantation – a long term study
    • Authors: Florian Meirer; Evgeny Demenev, Damiano Giubertoni, Lia Vanzetti, Salvatore Gennaro, Michele Fedrizzi, Giancarlo Pepponi, Georg Steinhauser, Vinayak Vishwanath, Majeed Foad, Massimo Bersani
      Pages: n/a - n/a
      Abstract: The evolution of very high dose arsenic implants in silicon formed by plasma immersion ion implantation and deposition (PIIID) using a non‐pulsed plasma source was studied over a time period of more than one year. The study focused on the effect of arsenolite micro‐crystal formation, enhanced oxidation, and the significant As dose loss from as implanted samples at room temperature. The study was carried out combining analytical evidence from SIMS, XPS, INAA, SEM, and optical microscopy suggesting a two stage process of As dose loss, the first implying arsenolite crystal growth and the second an out‐diffusion. In fact, comparison of samples fabricated using different PIIID parameters showed that crystal growth seems not to be the only process responsible for dose loss. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:42.129884-05:
      DOI: 10.1002/pssc.201300160
  • Observation of point defect injection from electrical deactivation of
           arsenic ultra‐shallow distributions formed by ultra‐low energy
           ion implantation and laser sub‐melt annealing
    • Authors: Evgeny Demenev; Florian Meirer, Zahi Essa, Damiano Giubertoni, Fuccio Cristiano, Giancarlo Pepponi, Salvatore Gennaro, Massimo Bersani, Majeed A. Foad
      Pages: n/a - n/a
      Abstract: The stability and the evolution of electrical properties of high concentration arsenic ultra‐shallow junctions in silicon have been studied with regard to their effect on the evolution of point defects. The activation of 2 keV 1 × 1015 cm‐2 As implants was performed using millisecond sub‐melt laser annealing at two different temperatures, 1100 and 1300 °C. The electrical deactivation upon subsequent thermal treatment at 700 °C was indirectly monitored through the diffusion of five 10 nm‐wide boron layers aimed to detect the injection of self‐interstitials coming from dopant clustering. Thermal treatments were repeated on samples implanted with Ge at condition similar to the As ones. The comparison helped to discriminate between interstitials coming from lattice damage evolution and dopant clustering. The results show the relevance of the laser annealing temperature in order to ensure junction stability in terms of active carrier concentration and junction depth. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:41.27483-05:0
      DOI: 10.1002/pssc.201300161
  • New RP‐CVD grown ultra‐high performance selectively
           B‐doped pure‐Ge 20 nm QWs on (100)Si as basis material for
           post‐Si CMOS technology
    • Authors: O. A. Mironov; A. H. A. Hassan, M. Uhlarz, S. Kiatgamolchai, A. Dobbie, R. J. H. Morris, S. Gabani, I. B. Berkutov, D. R. Leadley
      Pages: n/a - n/a
      Abstract: Magnetotransport studies at low and room temperature are presented for two‐dimensional hole gases (2DHG) formed in fully strained germanium (sGe) quantum wells (QW). Two designs of modulation doped heterostructure grown by reduced pressure chemical vapour deposition (RP‐CVD) were used and included a normal structure (doping above the Ge channel and inverted structure (doping beneath the Ge channel). The mobility (μH) for the normal structure was measured to be 1.34×106 cm2/Vs with a sheet density (ps) of 2.9×1011cm‐2at 1.5 K, and μH= 3970 cm2/Vs and ps ∼1×1011cm‐2 for room temperature, determined from simulation using the Maximum Entropy‐Mobility Spectrum Analysis (ME‐MSA) method. For the inverted structure a μH of 4.96×105 cm2/Vs and ps of 5.25×1011cm‐2was measured at 90 mK. From the temperature dependent amplitude of Shubnikov de Haas oscillations, the normal structure was found to have a very low effective mass (m*) value of 0.063 m0 and a ratio of transport to quantum lifetime (α) of ∼78. This extremely high α is indicative of the carrier transport being dominated by small angle scattering from remote impurities i.e. a sample having an extremely low background impurity level and very smooth hetero‐interfaces. The inverted structure had an m*of 0.069 m0 and α ∼29, which also indicates exceedingly high quality material. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:40.234139-05:
      DOI: 10.1002/pssc.201300164
  • Large boron‐interstitial cluster modelling in BF3 plasma implanted
    • Authors: Z. Essa; F. Cristiano, Y. Spiegel, Y. Qiu, P. Boulenc, M. Quillec, N. Taleb, N. Zographos, E. Bedel‐Pereira, V. Mortet, A. Burenkov, M. Hackenberg, F. Torregrosa, C. Tavernier
      Pages: n/a - n/a
      Abstract: BF3 plasma immersion ion implantation (PIII) is a promising technique in the race for highly boron doped P+/N ultra‐shallow junctions (USJs) in complementary metal oxide semiconductor (CMOS) silicon technologies. Implantation conditions used in BF3 PIII lead to high super‐saturations (≥1 × 1020 cm–3) of both boron and silicon interstitial atoms in the implantation region. In such conditions, very large loop‐shaped boroninterstitial clusters (BICs) are formed during subsequent thermal anneals, as confirmed by transmission electron microscopy (TEM) measurements. In this study, amorphizing BF3 PIII implants (10 keV, 5 × 1015 cm–2) followed by different thermal anneals were carried out in order to investigate the large BICs precipitation. A ”large BICs“ model based on moments approach allowed to reproduce the experimental data including boron diffusion profiles (obtained by SIMS) and boron electrical activation obtained by Hall effect sheet resistance measurements. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:39.4402-05:00
      DOI: 10.1002/pssc.201300165
  • Atomistic investigation of the impact of stress during solid phase
           epitaxial regrowth
    • Authors: Benoit Sklenard; Jean‐Charles Barbe, Perrine Batude, Pierrette Rivallin, Clement Tavernier, Sorin Cristoloveanu, Ignacio Martin‐Bragado
      Pages: n/a - n/a
      Abstract: An atomistic model to account for the impact of stress during solid phase epitaxial regrowth (SPER) is proposed. This model is based on the lattice kinetic Monte Carlo method. It has been compared with experimental data of regrowth velocity as a function of hydrostatic and non‐hydrostatic stresses. In particular, it permits to provide a physical explanation of the observations upon in‐plane uniaxial stress based on the assumption that {100} events occur through a dual‐timescale atomistic mechanism. Our model also catches the fact that compressive normal uniaxial stress and hydrostatic pressure result in an enhancement of the regrowth velocity with a similar activation volume. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:38.443919-05:
      DOI: 10.1002/pssc.201300166
  • Laser thermal anneal formation of atomically‐flat
           low‐resistive germanide contacts
    • Authors: K. Huet; M. Shayesteh, I. Toqué‐Tresonne, R. Negru, C. L. M. Daunt, N. Kelly, D. O'Connell, R. Yu, V. Djara, P. Carolan, N. Petkov, R. Duffy
      Pages: n/a - n/a
      Abstract: In this work, state‐of‐the‐art laser thermal annealing (LTA) is used to form germanide contacts on n‐doped Ge, and is compared to results generated by rapid thermal annealing (RTA). Surface topography, interface quality, crystal structure, and material stoichiometry are explored for both techniques. For electrical characterization, specific contact resistivities ϱc are extracted. It is shown that LTA can produce a uniform contact with a remarkably smooth substrate interface, with ϱc 2‐3 orders of magnitude lower than the equivalent RTA case. A ϱc of 2.84×10‐7 Ω.cm2 is achieved for optimized LTA parameters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:37.655204-05:
      DOI: 10.1002/pssc.201300168
  • The effect of Ge content on the formation and evolution of {113} defects
           in SiGe alloys
    • Authors: Larbi Laânab; Amine Belafhaili, Filadelfo Cristiano, Nikolay Cherkashin, Alain Claverie
      Pages: n/a - n/a
      Abstract: The aim of this work is to study the influence of the Ge content on the {113} defects formed, after a (35 keV, 1 × 1015 Ge+/cm2) preamorphization step followed by annealing at 680 °C, in relaxed SiGe alloys. For that, plan‐view Transmission Electron Microscopy (PTEM) under appropriate imaging conditions was used to study the {113} defects evolution as a function of the Ge content. Experimental results show that, increasing the Ge content results in a net reduction of both the density and the size of the {113} defects. Results analysis was performed in the framework of the “excess interstitials” model which describes perfectly the observed decrease of the {113} defects density in Si. Moreover, through a confrontation between the TEM observations and the predictions of this model, we show that the density of the interstitials contained in the defects (deduced from PTEM images) is a quasi linear function of the density of excess interstitials generated during the preamorphization step beneath the c/a interface, as calculated by the SRIM code. We conclude that collisional arguments can appropriately explain the observed evolution of the {113} defects density as a function of the Ge content. Meanwhile, the observed reduction of the {113} defects size with the Ge content, may be ascribed to a decrease of the transport capacity DiCi*, responsible for the defects growth. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:36.6628-05:00
      DOI: 10.1002/pssc.201300177
  • Challenges in CMOS‐based images
    • Authors: Francois Roy; A. Tournier, H. Wehbe‐Alause, F. Blanchet, P. Boulenc, F. Leverd, L. Favennec, C. Perrot, L. Pinzelli, M. Gatefait, N. Cherault, D. Jeanjean, J. P. Carrere, C. Augier, S. Ricq, D. Herault, S. Hulot
      Pages: n/a - n/a
      Abstract: High resolution CMOS image sensor demand is driven by consumer applications like mobile phone or digital still camera. To maintain the image quality, we have to save the signal to noise ratio (SNR) despite the number of photons reduction gathered by the pixel. In this paper, we present how back‐side illumination technology could help to recover signal and how to optimize the process and device in order to reduce the noise. A quantum efficiency larger than 70% is targeted to justify efforts done on BSI process development. We also have to pay attention to pixel to pixel crosstalk coming from free carrier diffusion. To overcome this parasitic phenomenon, deep trench isolation (DTI) should be considered in order to significantly reduce crosstalk between two neighboring pixels. The second main noise contributor related to BSI process is the dark current signal. Dark current less than 1 aA per pixel at room temperature is mandatory to save the image quality at low light level. Therefore, all the Si‐SiO2 interfaces at the pixel side walls have to be processed without any process damage to reduce as much as possible the surface defects. On top of that, side wall implantation and side wall dielectric fabrication have been optimized to reduce this noise source. The pixel layout has to be fully optimized also to collect and store charges properly. With respect to the 3D pixel shape, a new fully depleted pinned photodiode with vertical charge storage and no lag has been developed. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:35.77739-05:0
      DOI: 10.1002/pssc.201300378
  • Thermal properties of quantum devices in integrated circuits embedded in a
           chip environment
    • Authors: M. Käso; U. Wulf, J. Kuˇcera, H. Richter, J. Höntschel
      Pages: n/a - n/a
      Abstract: We consider a thermal model for an integrated circuit including its chip environment. As the simplest choice, the active device layer (integrated circuit) consists of an array of replicas of the same quantum device with the same time depended average temperature. Modeling the chip environment we assume this active layer is sandwiched between two coplanar heat reservoirs. The top heat reservoir represents the wiring layer of the chip (‘back‐end of line’). Its temperature is predominantly determined by the dissipated Joule heat in the wiring, typically in the order of one hundred degrees of Celsius. The bottom reservoir represents the cooling unit at about room‐temperature. We solve the coupled equations describing thermal transport between the active layer and surrounding heat reservoirs and electrical transport in the quantum devices. The stationary working temperatures of the considered quantum devices can be found from a fix‐point problem. A proper linearization of the complete time‐depended problem yields the stability of these fixpoints. Numerical solutions for a device layer consisting of identical nano‐transistors are given for selected parameters. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:34.690255-05:
      DOI: 10.1002/pssc.201300203
  • Electrical and optical characterization of extended defects induced in
           p‐type Si after Si ion implantation
    • Authors: Cloud Nyamhere; Fuccio Cristiano, Francios Olivie, Elena Bedel‐Pereira, Zahi Essa
      Pages: n/a - n/a
      Abstract: In this work we present the analysis of small interstitial clusters (ICs) introduced in p‐type Si after ion implantation using deep level transient spectroscopy (DLTS) and photoluminescence. Silicon ions with energy 380 keV and fluence of 1.0 x 1012 cm‐2 have been implanted into bulk p‐type Si and post‐implant annealing at temperatures between 500 oC and 800 oC specifically to create small interstitial cluster (ICs) defects. In the samples annealed at 500 oC, DLTS spectra show deep level hole traps at EV + 0.20 eV, EV + 0.25 eV, EV + 0.36 eV, and EV + 0.50 eV. The hole traps EV + 0.36 eV and EV + 0.50 eV have been attributed to the small Si self‐interstitial clusters. After increasing the post‐implant anneals to 600 oC there is a significant decrease in defect concentration and all the defects are annealed‐out at 700 oC. Photoluminescence (PL) spectroscopy of the samples reveals optical band levels, at 1218 nm (1.019 eV), and 1233 nm (1.007 eV) which have both been attributed to interstitial cluster defects. The interstitial cluster‐related optical band levels have been observed in the samples annealed at 500 oC which correlate well with DLTS measurements. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:33.733934-05:
      DOI: 10.1002/pssc.201300204
  • Atomic scale Monte Carlo simulations of BF3 plasma immersion ion
           implantation in Si
    • Authors: Antonino La Magna; Giuseppe Fisicaro, Giuseppe Nicotra, Yohann Spiegel, Frank Torregrosa
      Pages: n/a - n/a
      Abstract: We present a numerical model aimed to accurately simulate the plasma immersion ion implantation (PIII) process in micro and nano‐patterned Si samples. The code, based on the Monte Carlo approach, is designed to reproduce all the relevant physical phenomena involved in the process. The particle based simulation technique is fundamental to efficiently compute the material modifications promoted by the plasma implantation at the atomic resolution. The accuracy in the description of the process kinetic is achieved linking (one to one) each virtual Monte Carlo event to each possible atomic phenomenon (e.g. ion penetration, neutral absorption, ion induced surface modification, etc.). The code is designed to be coupled with a generic plasma status, characterized by the particle types (ions and neutrals), their flow rates and their energy/angle distributions. The coupling with a Poisson solver allows the simulation of the correct trajectories of charged particles in the void regions of the micro‐structures. The implemented model is able to predict the implantation 2D profiles and significantly support the process design. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:32.75214-05:0
      DOI: 10.1002/pssc.201300289
  • Determination of the Si Young's modulus between room and melt temperature
           using the impulse excitation technique
    • Authors: Akhilesh K. Swarnakar; Omer Van der Biest, Jan Vanhellemont
      Pages: n/a - n/a
      Abstract: Stress induced by the thermal gradients near the meltsolid interface affects the intrinsic point defect properties and the quality of single crystal Si grown from a melt. Also during device processing, stress in the Si substrate influences point defect behavior during thermal treatments. To be able to simulate and control the stress distribution one needs to know the elastic constants of single crystal Si at high temperatures. In the present study, the vibrational properties of single crystal Si samples are studied between room and melt temperature using the impulse excitation technique. From the measurements, the temperature dependent Young's moduli E〈ijk〉 of moderately doped Czochralski‐grown Si samples are extracted in the 〈100〉, 〈110〉 and 〈111〉 crystallographic directions. Close to the melt temperature, very high Young's moduli values between 110 and 160 GPa are obtained, depending on the crystallographic direction. Empiric expressions are derived for the temperature dependence of E〈100〉, E〈110〉 and E〈111〉 and of the elastic compliances s11 and s12 + s44/2, useful for application in process simulation. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:31.951636-05:
      DOI: 10.1002/pssc.201300101
  • Resistivity changes of low resistivity Si substrates by rapid thermal
           processing and subsequent annealing
    • Authors: X. Zhang; X. Ma, C. Gao, T. Xu, J. Zhao, P. Dong, J. Vanhellemont
      Pages: n/a - n/a
      Abstract: The resistivity change of low resistivity Si substrates by rapid thermal processing (RTP) and subsequent low tem‐perature annealing is reported. The observed resistivity increase after RTP can be explained by dopant deactivation due to trapping by dopant atoms of intrinsic point defects created during the high temperature step. Similar dopant deactivation is observed during growth of low resistivity single crystals or epitaxial layers. The stability of the intrinsic point defect‐dopant clusters and the recovery of resistivity is studied by low temperature anneals ranging from 300 to 650 °C. Results are presented on As (3‐5 mΩcm), P (1‐2 mΩcm), (17‐18 mΩcm) and B (16‐17 mΩcm) doped Si substrates. The observations are explained on the basis of a continuum model for intrinsic point point defect trapping by dopants. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:30.980779-05:
      DOI: 10.1002/pssc.201300107
  • Spin‐on‐dopant phosphorus diffusion in germanium thin films
           for near‐infrared detectors
    • Authors: V. Sorianello; A. De Iacovo, L. Colace, A. Fabbri, L. Tortora, G. Assanto
      Pages: n/a - n/a
      Abstract: Threading dislocations in germanium thin films on silicon introduce acceptor states in the germanium bandgap close to the valence band. Thus, highly defected germanium thin films spontaneously exhibit a p‐type behavior. Here we report on spin‐on‐dopant diffusion of phosphorus in thermally evaporated, highly defected germanium thin films. We demonstrate effective compensation of the acceptor states associated to dislocations by means of post‐growth doping. We discuss phosphorus diffusion in these highly defected films and pinpoint the benefits of spin‐on‐doping by realizing and testing near‐infrared photodiodes in evaporated Ge on Si, achieving high responsivities which compare well with those of state‐of‐the‐art Ge p‐i‐n photodiodes. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:29.595074-05:
      DOI: 10.1002/pssc.201300114
  • Point defect engineering study of phosphorus ion implanted germanium
    • Authors: M. A. Razali; M. Secchi, M. Bersani, R. M. Gwilliam
      Pages: 9 - 11
      Abstract: We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus electrical activation using point defect engineering method by introducing an excess of point defects in germanium prior to the phosphorus implantation. The focus is on studying the phosphorus activation and diffusion as a function of germanium co‐implant energy. Hall Effect and Secondary Ion Mass Spectrometry (SIMS) measurements are employed for characterisation of phosphorus activation and diffusion, respectively. Phosphorus activation was improved at higher annealing temperature for the implants with germanium co‐implant. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:21.806355-05:
      DOI: 10.1002/pssc.201300155
  • Deactivation of phosphorus in silicon due to implanted nitrogen
    • Authors: Ruey‐Dar Chang; Chih‐Hung Lin
      Pages: 24 - 27
      Abstract: Deactivation of phosphorus due to nitrogen incorporation was quantitatively investigated. Coimplantation was performed to produce nitrogen profiles overlapping phosphorus profiles in preamorphized silicon. Nitrogen was found to retard phosphorus activation after recrystallization of the amorphous layer. When phosphorus activation was completed, a gap of dopant activation level was observed between samples implanted with and without nitrogen. The gap of the activation level increased linearly with the doses of nitrogen and phosphorus. This implies formation of inactive complexes by pairing of phosphorus and nitrogen atoms. However, the gap disappeared when the peak profile of nitrogen shifted toward the surface during additional annealing at 750 °C for long times. This indicates that the complexes were not stable and therefore dissolved with nitrogen diffusion. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:14.659111-05:
      DOI: 10.1002/pssc.201300131
  • Low temperature plasma oxidation for advanced 3D CMOS‐based devices
    • Authors: J. Niess; W. Kegel, W. Lerch
      Pages: 37 - 40
      Abstract: The required temperature in semiconductor process technology is going towards two extreme directions. Either very high temperatures (up to 1300 °C) with very short durations on the order of milliseconds are required for highest dopant activation, or extremely low temperatures are needed for forming high‐quality dielectrics with minimum dopant deactivation and redistribution. This contribution describes a new microwave plasma oxidation apparatus with unique features addressing the before‐mentioned low‐temperature process requirements. With this new technique the oxide growth rate was studied as a function of time, gas ambient, pressure, applied microwave power and silicon substrate parameters to determine crystallographic oxidation rate anisotropy and dopant concentration independent oxidation at temperatures well below 500 °C. The “More Moore” approach of geometrical scaling in 2D will soon come to a physical end and therefore new requirements related to the thermal budget occur. Additionally the transition from 2D to 3D devices requires extremely conformal oxide growth. Both the low temperature and conformal oxide growth will be demonstrated on test structures. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:20.901606-05:
      DOI: 10.1002/pssc.201300154
  • More Moore meets More than Moore: Enabling healthcare applications
    • Authors: Sywert H. Brongersma; Michiel Blauw, Marcel Zevenbergen, Devrez Karabacak, Roman Vitushinsky, Van Anh Dam, Mercedes Crego Calama, Rudolf Vullers, Zeng Zeng, Rob van Schaijk
      Pages: 46 - 49
      Abstract: Western societies all see their healthcare costs outpace GDP growth. To reverse this trend, several public and private initiatives were taken in the last years to make healthcare more cost efficient. It is anticipated that micro and nano‐system technology will help enable an increase in the functionality of lifestyle and healthcare devices to gradually reduce cost. This builds on the scaling of microelectronics that additionally provides opportunities for reducing both form factor and power requirements. In the next decade, body area network technology will be one of the advancements that provides medical, lifestyle, assisted living, sports or entertainment functions for the user. Such a network comprising a series of miniature sensor nodes, implanted or located around the body should be able to communicate with other sensor nodes and/or with a gateway node that provides a connection to the outside world using a standard telecommunication infrastructure. Early deployment of technology in different application cases are translated into critical technology obstacles that need to be solved in order to enable widespread deployment. For the development of smaller and smarter systems with ever increasing autonomy, key technological challenges are addressed at the level of sensors, energy harvesting, ultra‐low‐power DSP, wireless connectivity, and integration and packaging. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:20.908717-05:
      DOI: 10.1002/pssc.201300182
  • New junctionless RADFET dosimeter design for low‐cost radiation
           monitoring applications
    • Authors: Djemai Arar; Fayçal Djeffal, Toufik Bentrcia, Mohamed Chahdi
      Pages: 65 - 68
      Abstract: This paper is devoted to the presentation of a quantitative analysis of the Junctionless Gate All Around RADFET (JL GAA RADFET) dosimeter, where the numerical simulation has been carried out using the Atlas 3‐D simulator. The impact of the total dose, alternative gate materials and the channel doping on the threshold voltage of the JL GAA RADFET is addressed. The obtained results have indicated a significant improvement in the subthreshold parameters when compared to the conventional GAA RADFET dosimeter. Therefore, the implementation of junctionless‐based sensors in the near future can provide more accurate results with low costs, in addition to alleviating many difficulties in the measurement procedure. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:20.06837-05:0
      DOI: 10.1002/pssc.201300146
  • TCAD simulation of thermally evaporated germanium
    • Authors: A. De Iacovo; V. Sorianello, L. Colace, G. Assanto
      Pages: 69 - 72
      Abstract: Epitaxial growth of germanium on silicon produces large misfit and threading dislocation densities which dramatically affect electronic properties of Ge. For this reason, TCAD standard models and parameters, optimized for bulk Ge, fail when applied to Ge epilayers. In this work we describe a novel approach for the simulation of highly defected germanium films grown by thermal evaporation. We also take into account the gradient of defect concentration depending on the germanium thickness. The proposed model is successfully employed for TCAD simulations of Ge‐on‐Si pn heterojunction photodiodes, demonstrating good agreement with experimental data. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:28.497151-05:
      DOI: 10.1002/pssc.201300115
  • Challenges in spacer process development for leading‐edge
           high‐k metal gate technology
    • Authors: Fabian Koehler; Dina H. Triyoso, Itasham Hussain, Bianca Antonioli, Klaus Hempel
      Pages: 73 - 76
      Abstract: Transistor performance is a key enabler for state‐of‐the‐art electronic devices. Besides fast switching performance, low power consumption is a critical parameter for mobile products. The implementation of HfO2 as a gate dielectric with a high permittivity reduces leakage current and power consumption drastically. Metal gates and work function materials are required to adjust Fermi levels and are essential for device performance. In addition to these key elements of high‐k metal gate (HKMG) technology, encapsulation liners and spacers are found to have a significant impact. We show that the performance of HKMG transistors has a strong dependency on the film quality and growth conditions of the SiN spacers. A good conformality and excellent step coverage at low deposition temperature is achieved with an atomic layer deposition (ALD) process using dichlorosilane and ionized radicals of ammonia. This ALD process is superior to standard LPCVD and PECVD processes with regards to thickness control, within‐wafer‐uniformity and matching of the thickness values between dense and isolated transistors. ALD SiN is applied as a spacer to define the implant profiles. The impact of the ALD SiN spacers on transistor universal curve, miller capacitance and Vt is demonstrated. Further application is a hard mask for selective epitaxy of SiGe. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:22.714092-05:
      DOI: 10.1002/pssc.201300157
  • Gate‐engineering‐based approach to improve the nanoscale DG
           MOSFET behavior against interfacial trap effects
    • Authors: Toufik Bentrcia; Fayçal Djeffal, Djemai Arar, Zouhir Dibi
      Pages: 77 - 80
      Abstract: In this paper, we propose a numerical investigation based framework for the analysis of a new MOSFET device, which is motivated by gate engineering and junctionless channel paradigms. The device immunity against the hot carrier effect is evaluated by comparing the obtained relative degradation in the threshold voltage to its counterparts in the conventional and single junctionless double gate MOSFETs. It is found that our proposed design can efficiently deal with the hot carrier and short channel effects. As a result, the gate‐engineering‐based design for junctionless channel structures appears to be of potential importance in the development of nanoscale devices dedicated to digital circuit applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:16.619708-05:
      DOI: 10.1002/pssc.201300134
  • Design and simulation of optically controlled field effect transistors
    • Authors: V. Sorianello; L. Colace, S. Rajamani, G. Assanto
      Pages: 81 - 84
      Abstract: Technology roadmaps identify the transmission bottleneck as one of the major challenges at high frequencies and in compact geometries. Increasing bandwidth and massive data processing prompt for the use of optics over short distances, down to board‐to‐board, chip‐to‐chip and even intra‐chip. In this framework, optical to electric converters are key elements. We investigate the feasibility of an optically controlled field effect transistor (FET), a device capable of switching when driven by light (rather than voltage) thanks to a photosensitive gate. We develop a physical model in order to simulate with TCAD the modulation of FET channel conductivity, using drift‐diffusion with optical generation. Current modulation of more than one order of magnitude with 1 µW optical power and time response lower than 100 ps can be achieved. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:26.647564-05:
      DOI: 10.1002/pssc.201300128
  • Formation energy of intrinsic point defects in nanometer‐thick Si
           and Ge foils and implications for Ge crystal growth from a melt
    • Authors: Eiji Kamiyama; Koji Sueoka, Jan Vanhellemont
      Pages: 85 - 88
      Abstract: Formation energies of vacancies and self‐interstitials in nanometer‐thick Si and Ge foils are calculated by means of Density Functional Theory applying thin film models. Plate models consisting of six to sixteen atomic layers with c(4×2) dimer structures on both surfaces with a vacuum slab are used. The formation energies Ef of the intrinsic point defects of Si and Ge in the middle of the foil and obtained from the twelve layer models, are in good agreement with reported values for bulk material. In all cases, Ef in the middle of the foil decreases with decreasing foil thickness. Using the same twelve or more layers thin plate models for Si and Ge thus also allows comparing the formation energies of intrinsic point defects in the bulk. The thermal equilibrium concentration of Ge self‐interstitials near melt temperature is more than one order of magnitude lower than that of Si self‐interstitials while the vacancy concentrations are of same order of magnitude. Contrary to Si, the diffusivity of Ge self‐interstitials can therefore not recover the unbalance of the thermal equilibrium concentrations during crystal growth, even if the growth rate is reduced to very low values. This is the reason why Ge crystals grown from a melt are always vacancy‐rich which results in void formation in‐dependent of the crystal growth conditions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:13.564364-05:
      DOI: 10.1002/pssc.201300112
  • Simulation of the boron build‐up formation during melting laser
           thermal annealing
    • Authors: M. Hackenberg; K. Huet, R. Negru, G. Fisicaro, A. La Magna, N. Taleb, M. Quillec, P. Pichler
      Pages: 89 - 92
      Abstract: In this work, we present a model describing the boron redistribution during laser thermal annealing in the melting regime based on the adsorption of boron atoms at the solid‐liquid interface. To validate the model, we performed SIMS measurements on silicon samples implanted with boron with an energy of 3 keV and doses of 3 × 1013 cm‐2 and 4 × 1014 cm‐2 annealed with a XeCl excimer laser with a wavelength of 308 nm, a pulse duration of 160 ns, and up to 10 consecutive pulses. After calibration, our model is able to reproduce the measured profiles for the different process conditions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:24.890037-05:
      DOI: 10.1002/pssc.201300156
  • Analytical expressions for the drain current of a nanotransistor in the
           off‐state regime
    • Authors: M. Krahlisch; U. Wulf, J. Kučera, H. Richter, J. Höntschel
      Pages: 113 - 116
      Abstract: Recently, we have suggested a scale‐invariant numerical model for a planar nanotransistor based on a Fowler‐Nordheim‐type of formula. In this this model we introduce a set of approximations to obtain simple analytical expressions for the drain current in the off‐state regime. For this purpose the saddle point approximation is applied to the Fowler‐Nordheim integral. Furthermore, we are using the WKB‐expression for transmission coefficient and a series approximation for Fermi‐Dirac integrals by Mc Dougal and Stoner to evaluate the supply function. The resulting analytical formula is in qualitative agreement with the traces of an experimental transistor. It becomes quite simple for small gate voltages, i.e. in the deep off‐state regime. Systematic steps to improve our approximations towards a quantitative agreement are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:27.54371-05:0
      DOI: 10.1002/pssc.201300122
  • Dopant/carrier profiling for 3D‐structures
    • Authors: Wilfried Vandervorst; Andreas Schulze, Ajay Kumar Kambham, Jay Mody, Matthieu Gilbert, Pierre Eyben
      Pages: 121 - 129
      Abstract: With the transition from planar to three‐dimensional device architectures such as FinFets, TFETs and nanowires, new metrology approaches are required to characterize the 3D‐dopant and carrier distributions precisely, as their positioning relative to gate edges, 3D‐distribution, conformality, and absolute concentration determine the device performance in great detail. Concepts like atomprobe tomography with its inherent 3D‐resolution are obviously a potential solution although its routine application is still hampered by localization problems, reconstruction artifacts due to inhomogeneous evaporation, sensitivity due to the limited statistics, poor tip yield, etc. Although on the other hand concepts like scanning spreading resistance microscopy are inherently 2D, extensions towards 3D appear possible either by the design of dedicated tests structures or by novel approaches such as mechanical scalping. Ultimately even 1D‐methods like secondary ion mass spectrometry can be used to study dopant incorporation in 3D‐structures. When assessing their performance as metrology tool for 3D‐devices and structures one needs to address not only their ability to achieve 3D‐spatial resolution but also the physical property which is probed, i.e. dopants versus carriers, as well as the complexity of the method used. An evaluation in terms of time to data is equally important as the technical capabilities. The application of these methods to 3D‐structures and confined volumes, has demonstrated that the changing surface/volume ratios in confined devices versus blanket films lead to phenomena (dopant deactivation, enhanced diffusion,..) which cannot be observed in blanket experiments. Hence more emphasis should be placed on the analysis of device and structures with the relevant dimensions relative to the exploration of blanket experiments. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:23.307568-05:
      DOI: 10.1002/pssc.201300329
  • Characterisation of electrically active defects
    • Authors: Ray Duffy; Anco Heringa
      Pages: 130 - 137
      Abstract: Defects may arise in the semiconductor substrate and at interfaces due to the processing used to fabricate transistors and circuits. The development of low‐thermal‐budget processes, which is advantageous in many ways, unfortunately reduces the likelihood of annealing out these electrically active defects. Electrical characterisation using simple diode structures yields valuable information; not only the absolute leakage current density value, but also carrier lifetimes, leakage activation energies, and diode ideality factor. Coupled with material analysis techniques, they can provide a detailed picture of the problems associated with process‐induced defects, and supply insight that can target optimised processes. In this paper the technological relevance of electrically active defects, their impact on device performance and power supplies, as well as their electrical and material characterisation, will be discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:18.904767-05:
      DOI: 10.1002/pssc.201300144
  • Source/drain induced defects in advanced MOSFETs: what device electrical
           characterization tells
    • Authors: Mireille Mouis; Jae Woo Lee, Daeyoung Jeon, Ming Shi, Minju Shin, Gérard Ghibaudo
      Pages: 138 - 145
      Abstract: A wealth of convergent results are indicating that point defects originating from the processing of source/drain (S/D) regions are strongly involved in many parameters that rule the operation mechanisms and ultimately the performance of transistors. One example of such effect is the mobility degradation which is observed at short gate length in most, if not all, technologies. Defects can also been traced by their implication in leakage currents. Their dynamics has been found as well to be involved in the activation/deactivation processes and the final series resistance of S/D regions, enlightening the role of additional interfaces that are being introduced with thin film SOI and nanowire technologies. These complex effects, which are becoming 3D in present technologies, are very difficult to characterize by means of structural characterization. On the other hand, simulation based predictions have strongly improved. However, due to the complex processes involved, they still require the adjustment of a large number of parameters, which can usually be validated in model configurations only. In this paper we will review and complement some of our recent results obtained from electrical characterization, for a variety of advanced MOS transistor architectures, with focus on the analysis of the parameters which can be influenced by the presence of defects. It is shown that in‐depth electrical characterization can provide strong experimental indications about point defects lateral distribution, with the advantage of probing the real device. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:22.186651-05:
      DOI: 10.1002/pssc.201300317
  • Impedance spectroscopy of polysilicon in SOI structures
    • Authors: Anatoly Druzhinin; Ihor Ostrovskii, Yuriy Khoverko, Stepan Nichkalo, Iurii Kogut
      Pages: 156 - 159
      Abstract: Polycrystalline silicon layers on the surface of oxidized silicon substrate, i.e. SOI‐structures, with initial boron concentration (of about 2.4 × 1018 cm‐3 ÷ 1.7 × 1020 cm‐3) in the vicinity to metal‐insulator transition have been investigated. Experimentally the AC performances for both non‐recrystallized and recrystallized layers correlate with DC measurements. Conductivity caused by the hopping between localized states with energy magnitude close to the Fermi level, has a weak temperature dependence in the ranges where the Shklovskii‐Efros law applies. In this case, the percolation type of charge carrier transport is observed. In contrast, the hopping conduction between localized states near the band edges has a strong temperature dependence, where the Mott law is obeyed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-12-09T05:10:25.712343-05:
      DOI: 10.1002/pssc.201300149
  • Structural characterization of in‐situ silicided contacts textured
           on p‐type [001] silicon
    • Authors: Paolo Badalà; Giuseppe Faro, Cinzia Marcellino, Giovanna Pellegrino, Antonello Santangelo, Alessandra Alberti
      Pages: 160 - 163
      Abstract: Nickel silicide is widely used to realize contact terminals of integrated circuits and is usually formed by ex‐situ heating treatments. In‐situ reactions during sputter deposition of a Ni layer onto a HF p‐type [001] Si substrate have been investigated in this work, by means of transmission electron microscopy, X‐ray diffraction and X‐ray reflectivity analyses. A thin layer of polycrystalline silicide, with extremely flat interfaces and in fiber texture with the Si substrate, has been obtained by introducing a sputter etching step just before Ni deposition and properly modulating its duration. The work has also been aimed to decouple the thermal impact of sputter etching from its effect on surface cleaning, disclosing its key role in the whole reaction process. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:15.812731-05:
      DOI: 10.1002/pssc.201300132
  • Role of the early stages of Ni‐Si interaction on the formation of
           transrotational Ni‐silicides
    • Authors: Alessandra Alberti; Corrado Bongiorno, Corrado Spinella, Antonino La Magna
      Pages: 164 - 168
      Abstract: Here we provide an overview on the crucial role played by the early stages of Ni‐Si interaction on the reaction process and on the scalability of the reaction products. During the early stages, a precursor layer (a Ni‐Si mixed layer) is formed at the deposition stage, whose properties can be tuned in a proper and convenient way. With this method, transrotational Ni‐silicide layers can be formed on [001] silicon substrate in a wide range of conditions. A transrotational structure represents an alternative order status possible for thin films allowing them to release the strain accumulated in the attempt to realise a hetero‐epitaxial couplings with the substrate. Transrotational layers offer wide reaction and structural stability windows as well as a good electrical behaviour. Their scalability down to 14 nm was tested, and it was verified that the layer performances are even preserved if compared to reference poly‐thick layers (e. g. uniformity, structural stability, layer conductivity, low contact resistance). (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2013-11-25T06:40:17.734275-05:
      DOI: 10.1002/pssc.201300142
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