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  • 301. Grivickas, V.
    et al.
    Grivickas, Paulius
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Linnros, Jan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Galeckas, A.
    Two-photon spectroscopy of 4H-SiC by using laser pulses at below-gap frequencies2004In: SILICON CARBIDE AND RELATED MATERIALS 2003, PRTS 1 AND 2 / [ed] Madar, R; Camassel, J, 2004, Vol. 457-460, p. 605-608Conference paper (Refereed)
    Abstract [en]

    Measurement of two-photon absorption (TPA) coefficient beta in epitaxial 4H-SiC is performed over a wide spectral range using time-resolved spectroscopy and tunable wavelength laser pulses. We find that beta increases exponentially between 0.1 cm/GW < beta < 10 cm/GW over the two-photon energy range 4 eV > 2hv > 5 eV and then saturates to value of 50 cm/GW approaching 2hv = 6.5 eV. The direct optical transitions at the M critical point of zone structure are shown to contribute mainly to the band edge of the TPA spectra.

  • 302.
    Gudmundson, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Generalized Frequency Hopping in Mobile Radio Systems (Part 1. Multiple Access Method)1993Report (Other academic)
  • 303. Gösch, Michael
    et al.
    Blom, Hans
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Holm, Johan
    Heino, Toni
    Rigler, Rudolf
    Hydrodynamic Flow Profiling in Microchannel Structures by Single Molecule Fluorescence Correlation Spectroscopy2000In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 72, no 14, p. 3260-3265Article in journal (Refereed)
    Abstract [en]

    In this paper we demonstrate high spatial resolution hydrodynamic flow profiling in silicon wafer based microchannels using single molecule fluorescence correlation spectroscopy (FCS). We have used confocal fluorescence microscopy to detect single tetramethylrhodamine (TMR-4-dUTP) biomolecules traversing a l fL volume element defined by an argon laser beam focus. By elevating a (10-10 M) reservoir of diluted analyte, a continuous hydrodynamic flow through the microstructure could be accomplished. The microchannel was then scanned with a diffraction-limited focus in 1-μm steps in both the vertical and the horizontal directions to determine the flow profile across a 50 × 50 μm2 channel. The flow profile measured was parabolic in both dimensions, thereby showing a Poiseuille laminar flow profile. Future microstructures can hereby be nondestructively investigated with the use of high spatial resolution confocal correlation microscopy.

  • 304. Gösch, Michael
    et al.
    Blom, Hans
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Rigler, Rudolf
    Anderegg, Sylvain
    Lasser, Theo
    Magnusson, Anders
    Hård, Sverker
    Multi-focal dual-color cross-correlation spectroscopy of single biomolescules using diffractive-optical-elements2003In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794Article in journal (Refereed)
  • 305.
    Göthelid, Mats
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Le Lay, G.
    Karlsson, Ulf O.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    An ordered layer of molecular iodine on Ge(100) 2x12004In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 556, no 03-feb, p. 203-212Article in journal (Refereed)
    Abstract [en]

    Adsorption of iodine on the Ge(1 0 0) (2 x 1) surface has been investigated by core level and valence band photoelectron spectroscopy and scanning tunnelling microscopy. Iodine binds to dimer atom dangling bonds without disrupting the dimers at all coverages. At saturation a c(2 x 2) ordered layer of molecular iodine develops on top of a (2 x 2) ordered structure of atomic iodine binding to asymmetric Ge-dimers. Annealing destroys the molecular character and etches the surface by Ge dimer bond breaking and attachment of additional iodine to these Ge atoms to form GeI2, which desorbs from the surface.

  • 306.
    Göthenberg, Andreas
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Modeling and Analysis of Wideband Sigma-Delta Noise Shapers2003Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    The continuous evolution of CMOS technologies towards deepsubmicron processes has provided new opportunities forintegration of mixed-signal systems on single monolithicintegrated circuits. In order to find the optimal usage of CMOStechnology and robustness against undesired mixed-signalcouplings, new approaches to CMOS front-end integration areneeded. The key aspect for such new architectures is theidentification of the optimal sampling devices and theirarchitecture. In this work the aim has been to utilizesigma-delta noise shapers for wideband applications, e.g. radiosystem applications having a digital baseband of 1 - 3 MHz. Thesigma-delta noise shaper uses oversampling to trade resolutionin time for resolution in amplitude. Until recently, technologyconstraints have limited the use tothe lower frequency ranges,e.g. audio applications. The sigma-delta noise shaper utilizesdigital signal processing extensively, which means thattolerances on the analog circuit blocks can be significantlyrelaxed and at the same time it is possible to benefit fromfast signal processing provided by digital deep submicron CMOStechnologies. The sigma-delta noise shaper is therefore anattractive candidate for wideband applications.

    In this work, appropriate sigma-delta modulator structureshave been modeled and analyzed for wideband applications.Simultaneous demands for high sample rate and low oversamplingratio within the technology constraints have been addressed.Furthermore, a low-distortion wideband sigma-delta noise shaperstructure is presented. A critical block of the sigma-deltamodulator is the sampling switch, as its nonlinearities aredirectly distorting the input signal. A set of samplingswitches have been analyzed in detail regarding dynamic andfrequency behavior. Process scaling towards smaller geometriesin deep submicron CMOS has also resulted in negative effects onthe performance. Substrate noise coupling has become a veryimportant limitation on the design of mixed-mode circuits indeep submicron CMOS today. A brief overview and some results onthis problem are also presented.

  • 307.
    Hagsand, Olof
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Marsh, Ian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hanson, K
    Sicsophone: A low-delay Internet telephony tool2003In: PROCEEDINGS OF THE 29TH EUROMICRO CONFERENCE - NEW WAVES IN SYSTEM ARCHITECTURE, 2003, p. 189-195Conference paper (Refereed)
    Abstract [en]

    The end to end delay is a critical factor in the perceived quality of service for Voice over IP applications. Sicsophone is a complete VoIP system that couples the low level features of audio hardware with a standard jitter buffer playout algorithm. Using, the sound card directly eliminates intermediate buffering as well as providing fine control over timers needed by a soft real-time application such as VoIP A statistical based approach for inserting packets into audio buffers is used in conjunction with a scheme for inhibiting unnecessary fluctuations in the system. We also present mouth-to-ear delay measurements for selected VoIP applications and show that several hundreds of milliseconds can be saved by using the techniques described in this paper A prototype for both UNIX and Windows platforms has been implemented, demonstrating that our system adapts to network: conditions whilst maintaining low delays.

  • 308.
    Hagsand, Olof
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Más, Ignacio
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Marsh, Ian
    Swedish Institute of Computer Science.
    Karlsson, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Self-Admission Control for IP Telephony using Early Quality Estimation2004In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3042, p. 381-391Article in journal (Refereed)
    Abstract [en]

    If quality of service could be provided at the transport or the application layer, then it might be deployed simply by software upgrades, instead of requiring a complete upgrade of the network infrastructure. In this paper, we propose a self-admission control scheme that does not require any network support or external monitoring schemes. We apply the admission control scheme to IP telephony as it is an important application benefiting from admission control. We predict the quality of the call by observing the packet loss over a short initial period using an in-band probing mechanism. The quality prediction is then used by the application to continue or to abort the call. Using over 9500 global IP telephony measurements, we show that it is possible to accurately predict the quality of a call. Early rejection of sessions has the advantage of saving valuable network resources plus not disturbing the on-going calls.

  • 309. Hallett, M.
    et al.
    Lagergren, Jens
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Tofigh, A.
    Simultaneous identification of duplications and lateral transfers2004In: Proceedings of the Annual International Conference on Computational Molecular Biology, RECOMB, 2004, p. 347-356Conference paper (Refereed)
    Abstract [en]

    This paper introduces a combinatorial model that incorporates duplication events as well as lateral gene transfer events (a.k.a. horizontal gene transfer events). To the best of our knowledge, this is the first such model containing both of these events. A so-called dt-scenario is used to explain differences between a gene tree T and species trees S. The model is biologically as well as mathematically sound. Among other biological considerations, the model respects the partial order of evolution implied by 5 by demanding that the dt-scenarios are "acyclic". We present fixed parameter tractable algorithms that count the minimum number of duplications and lateral transfers, and more generally can compute the set of pairs (t, d) where d is the minimum number of duplications required by any explanation that requires t lateral transfers. This allows us to also compute a weighted parsimony score. We also show how gene loss events can be incorporated into our model. We also give an NP-completeness proof which suggests that the intractability is due to the demand that the dt-scenarios be acyclic. When this condition is removed, we can show that the problem is computable in polynomial time via dynamic programming. By generating "synthetic" gene and species trees via a birth-death process, we explored the capacity of our algorithms to faithfully reconstruct the actual number of events taken place. The results are positive.

  • 310.
    Hallén, Anders.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janson, M. S.
    Kuznetsov, A. Y.
    Aberg, D.
    Linnarsson, Margareta K
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Svensson, B. G.
    Persson, P. O.
    Carlsson, F. H. C.
    Storasta, L.
    Bergman, J. P.
    Sridhara, S. G.
    Zhang, Y.
    Ion implantation of silicon carbide2002In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 186, p. 186-194Article in journal (Refereed)
    Abstract [en]

    Ion implantation is an important technique for a successful implementation of commercial SiC devices. Much effort has also been devoted to optimising implantation and annealing parameters to improve the electrical device characteristics. However, there is a severe lack of understanding of the fundamental implantation process and the generation and annealing kinetics of point defects and defect complexes. Only very few of the most elementary intrinsic point defects have been unambiguously identified so far. To reach a deeper understanding of the basic mechanisms SiC samples have been implanted with a broad range of ions, energies, doses, etc., and the resulting defects and damage produced in the lattice have been studied with a multitude of characterisation techniques. In this contribution we will review some of the results generated recently and also try to indicate where more research is needed. In particular, deep level transient spectroscopy (DLTS) has been used to investigate point defects at very low doses and transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS) are used for studying the damage build-up at high doses.

  • 311.
    Hallén, Anders.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Keskitalo, N.
    Defect distributions in silicon implanted with low doses of MeV ions2002In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 186, p. 344-348Article in journal (Refereed)
    Abstract [en]

    Deep level transient spectroscopy (DLTS) is used to study the distributions as a function of depth of the single negative divacancy complex in n-type FZ silicon implanted with low doses of H, He and O ions, The energies of the incoming ions are chosen to correspond to the same projected range, i.e. about 24 mum. The defect distribution is found to be relatively broad as compared to Monte Carlo simulations of the initially created vacancy distribution, particularly for the case of proton implantation. Furthermore, it is shown that the yield of divacancies, per generated vacancy, increases slightly with incoming ion mass and is three times higher at half the projected range than in the damage peak.

  • 312. Han, S. H.
    et al.
    Eltsev, Y.
    Rapp, Östen.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Three-dimensional XY critical fluctuations of the dc electrical conductivity in Bi2Sr2CaCu2O8+delta single crystals2000In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 61, no 17, p. 11776-11779Article in journal (Refereed)
    Abstract [en]

    A method is presented to analyze the dc critical fluctuation conductivity Delta sigma of Bi2Sr2CaCu2O8+delta single crystals in zero magnetic field. Two crossovers are obtained upon approaching T-c; first the Ginzburg crossover from the mean-held region to the initial critical regime, where the critical exponent a of Delta sigma changes from -1/2 to -2/3, and then, closer to T-c, a crossover of alpha form -2/3 to 1/3 in the critical region. Good agreement is found with the expectations from the three-dimensional XY model.

  • 313. Han, S. H.
    et al.
    Lundqvist, B.
    Eltsev, Y.
    Rapp, Östen.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Studies of dynamic critical behaviour in YBa2Cu3O7-delta single crystals2000In: Physica. C, Superconductivity, ISSN 0921-4534, E-ISSN 1873-2143, Vol. 341, p. 1855-1856Article in journal (Refereed)
    Abstract [en]

    Up to now, the value of the dynamic critical exponent z is still an open question. We have studied this exponent in the intermediate (XY) critical regime in zero field for a set of high quality YBa2Cu3O7-delta Single crystals in terms of Fisher-Fisher-Huse (FFH) dynamic scaling, and using previously obtained values for the critical exponents cu of the de critical conductivity fluctuations. In this regime (i.e. the absence of Coulomb interactions), one would expect model-E dynamics (z = 1.5) to apply with the conserved charge-density conjugate to the phase fluctuations. However, we find the dynamic critical exponent to be z = 2, which is in agreement with the suggestion of FFH that due to plasma fluctuations, fully relaxational dynamics, model A (z = 2), should be appropriate.

  • 314.
    Han, Shunhui
    et al.
    KTH, Superseded Departments, Physics. KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Axnäs, Johan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zhao, B R
    Rapp, Östen
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Fluctuation conductivity at high temperatures in polycrystalline Hg, Tl-1223 - Is there ID fluctuation behavior?2004In: Physica. C, Superconductivity, ISSN 0921-4534, E-ISSN 1873-2143, Vol. 408, p. 679-680Article in journal (Refereed)
    Abstract [en]

    Detailed resistivity measurements were made for polycrystalline Hg1-xTlxBa2Ca2Cu3O8+delta (x = 0.2) in zero field and in the temperature region from zero resistance up to 300 K. The fluctuation conductivity Deltasigma was analyzed as a function of is an element of equivalent to In(T/Tc-mf) in the range -5.5 < Inc < -0.5. 1D behavior Of fluctuation conductivity was found at high temperatures (above the 2D regime) with a crossover temperature T-1*, above which the critical exponent was found to be -1.5.

  • 315. Hansson, B. T.
    et al.
    Arvidsson, M.
    Friberg, Ari T.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Pump-mode influence on the performance of end-pumped passively Q-switched lasers2002In: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 4, no 1, p. 29-32Article in journal (Refereed)
    Abstract [en]

    We present a simple way of adjusting the output performance of end-pumped passively Q-switched lasers. The method is based on changing the size of the pump mode within the active medium, and the approach is demonstrated both in theory and in practice. We show that it is possible to modify the repetition rate from 7 kHz to 1 MHz and the pulse length from 6 to 30 ns for the laser used in the experiments.

  • 316. Hansson, B. T.
    et al.
    Friberg, Ari T.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Eye-safe actively Q-switched microchip laser with an electro-absorbing semiconductor modulator2001In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 26, no 14, p. 1057-1059Article in journal (Refereed)
    Abstract [en]

    We present what we believe to be the first actively Q-switched monolithic microchip laser with a wavelength of 1.55 mum that uses an electro-absorbing semiconductor modulator. At an absorbed pump power of 130 mW and a switching voltage of 2.2 V, the laser produces 470-nJ pulses at a repetition rate of 10 kHz. The output is a stable single longitudinal mode with a center wavelength of 1.553 mu tm, and the transverse beam profile is close to an ideal Gaussian, with an M-2 value of 1.15.

  • 317. Hansson, B. T.
    et al.
    Friberg, Ari T.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Pulsed 1.55 mu m transmission mode microchip laser using semiconductor modulator2001In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 37, no 4, p. 223-225Article in journal (Refereed)
    Abstract [en]

    A semiconductor saturable absorber modulator is used, for the first time, in a passively Q-switched microchip laser in transmitting mode. The laser has a wavelength of 1.55 mum in a single longitudinal TEM, mode beam and has pulse characteristics that compare favourably with preciously reported data un comparable devices.

  • 318.
    Haralson, Erik
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Device design and process integration for SiGeC and Si/SOI bipolar transistors2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    SiGe is a significant enabling technology for therealization of integrated circuits used in high performanceoptical networks and radio frequency applications. In order tocontinue to fulfill the demands for these applications, newmaterials and device structures are needed. This thesis focuseson new materials and their integration into heterojunctionbipolar transistor (HBT) structures as well as using devicesimulations to optimize and better understand the deviceoperation. Specifically, a SiGeC HBT platform was designed,fabricated, and electrically characterized. The platformfeatures a non-selectively grown epitaxial SiGeC base,in situdoped polysilicon emitter, nickel silicide,LOCOS isolation, and a minimum emitter width of 0.4 μm.Alternately, a selective epitaxy growth in an oxide window wasused to form the collector and isolation regions. Thetransistors exhibited cutoff frequency (fT) and maximum frequency of oscillation (fMAX) of 40-80 GHz and 15-45 GHz, respectively.Lateral design rules allowed the investigation of behavior suchas transient enhanced diffusion, leakage current, and theinfluence of parasitics such as base resistance and CBC. The formation of nickel silicide on polysiliconSiGe and SiGeC films was also investigated. The formation ofthe low resistivity monosilicide phase was shown to occur athigher temperatures on SiGeC than on SiGe. The stability of themonosilicide was also shown to improve for SiGeC. Nickelsilicide was then integrated into a SiGeC HBT featuring aselectively grown collector. A novel, fully silicided extrinsicbase contact was demonstrated along with the simultaneousformation of NiSi on thein situdoped polysilicon emitter.

    High-resolution x-ray diffraction (HRXRD) was used toinvestigate the growth and stability of SiGeC base layers forHBT integration. HRXRD proved to be an effective, fast,non-destructive tool for monitoring carbon out-diffusion due tothe dopant activation anneal for different temperatures as wellas for inline process monitoring of epitaxial growth of SiGeClayers. The stability of the SiGe layer with 0.2-0.4 at% carbonwhen subjected to dopant activation anneals ranging from1020-1100&#176C was analyzed by reciprocal lattice mapping.It was found that as the substitutional carbon increases theformation of boron clusters due to diffusion is suppressed, buta higher density of carbon clusters is formed.

    Device simulations were performed to optimize the DC and HFperformance of an advanced SiGeC HBT structure with low baseresistance and small dimension emitter widths. The selectivelyimplanted collector (SIC) was studied using a design ofexperiments (DOE) method. For small dimensions the lateralimplantation straggle has a significant influence on the SICprofile (width). A significant influence of the SIC width onthe DC gain was observed. The optimized structure showedbalanced fT/fMAXvalues of 200+ GHz. Finally, SOI BJT transistorswith deep trench isolation were fabricated in a 0.25μmBiCMOS process and self-heating effects were characterized andcompared to transistors on bulk silicon featuring deep trenchand shallow trench isolation. Device simulations based on SEMcross-sections and SIMS data were performed and the resultscompared to the fabricated transistors.

    Key words:Silicon-Germanium(SiGe), SiGeC,heterojunction bipolar transistor(HBT), nickel silicide,selectively implanted collector(SIC), device simulation, SiGeClayer stability, high resolution x-ray diffraction(HRXRD),silicon-on-insulator(SOI), self-heating.

  • 319.
    Haralson, Erik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Malm, B. Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Johansson, T
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Influence of self heating in a BiCMOS on SOI technology2004In: ESSCIRC 2004: Proceedings of the 34th European Solid-State Device Research Conference, NEW YORK: IEEE , 2004, p. 337-340Conference paper (Refereed)
    Abstract [en]

    Self heating in a 0.25mum BiCMOS technology with different isolation structures is characterized. Thermal resistance values for single- and multiple-emitter devices are extracted and reported. The dependence of the thermal resistance on the emitter aspect ratio is critical to take into consideration when determining the isolation scheme for devices. 2-D electro-thermal simulations are performed and compared to experimental results. The impact of metallization on the self-heating in the device is examined through simulations.

  • 320.
    Haralson, Erik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Malm, B. Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Device design for a raised extrinsic base SiGe bipolar technology2004In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 48, no 11-okt, p. 1927-1931Article in journal (Refereed)
    Abstract [en]

    The impact of emitter, inside spacer, and SIC lateral scaling on the AC and DC performance of a raised extrinsic base SiGe HBT has been investigated using the ISE TCAD simulation package and design of experiments methods. Strong first order effects for all three variables were observed while the interactions of the variables had a weaker effect. It was found that as the emitter size shrinks towards 0.1 mum the impact of changes to inside spacer and SIC width on the current gain increased. The response surface design led to an optimized simulated transistor featuring f(T) and f(MAX) values of 214 and 332 GHz, respectively.

  • 321.
    Haralson, Erik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Sibaja-Hernandez, Arturo
    Xu, Mingwei
    Malm, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Radamson, Henry
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    HRXRD analysis of SiGeC layers for BiCMOS applications2004Conference paper (Refereed)
    Abstract [en]

    The use of HRXRD for the monitoring of the dopant activation anneal through the detection of carbon outdiffusion has been demonstrated. The advantages of HRXRD over other measurement techniques for in-line epi-growth monitoring are also discussed. HRXRD reciprocal space mapping was used to study the SiGe layer stability as a function of carbon concentration for vertically scaled layers designed for high performance BiCMOS applications. It was found that as the carbon concentration is increased there is a reduction of boron cluster formation, but an increase in defect density is also observed.

  • 322.
    Haralson, Erik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Suvar, Erdal
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Malm, B. Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Radamson, Henry H.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Wang, Yong-Bin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    The effect of C on emitter-base design for a single-polysilicon SiGe: C HBT with an IDP emitter2004In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 224, no 1-4, p. 330-335Article in journal (Refereed)
    Abstract [en]

    A differential epitaxy SiGe:C heterojunction bipolar junction transistor (HBT) design is reported and used to study the effect of carbon on junction formation as well as the effect of lateral design parameters on ac and dc performance. The device exhibits a high current gain (beta) of 1700 and a BVCEO of 1.8 V. The peak cutoff frequency (f(T)) and maximum oscillation frequency (f(MAX)) are 73 and 17 GHz, respectively. The effect of emitter overlap on f(T) was minimal, but it had a strong impact on dc performance. LOCOS opening size strongly impacted both ac and dc performance. In addition, the effect of carbon, base cap thickness, and rapid thermal anneal (RTA) temperature on the emitter-base (E-B) junction formation was studied.

  • 323.
    Haridi, Seif
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Van Roy, Peter
    Concepts, Techniques, and Models of Computer Programming2004Book (Refereed)
  • 324. Haussermann, U.
    et al.
    Bostrom, M.
    Viklund, P.
    Rapp, Östen.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Bjornangen, T.
    FeGa3 and RuGa3: Semiconducting intermetallic compounds2002In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 165, no 1, p. 94-99Article in journal (Refereed)
    Abstract [en]

    The intermetallic compounds FeGa3 and RuGa3 were prepared from the elements using a Ga flux and their structures were refined from single-crystal X-ray data. Both compounds crystallize with the FeGa3 structure type (tetragonal, space group P4(2)/mnm, Z=4). Electrical resistivity measurements revealed a semiconducting behavior for FeGa3 and RuGa3, which is in contrast to the good metallic conductivity observed for the isotypic compound CoGa3. The origin of the different electronic properties of these materials was investigated by first-principle calculations. It was found that in compounds adopting the FeGa3 structure type the transition metal atoms and Ga atoms interact strongly. This opens a d-p hybridization bandgap with a size of about 0.31 eV in the density of states at the Fermi level for 17-electron compounds (i.e., FeGa3 and RuGa3). The electronic structure of CoGa3 (an 18-electron compound) displays rigid band behavior with respect to FeGa3. As a consequence, the Fermi level in CoGa3 becomes located above the d-p hybridization gap which explains its metaltic conductivity.

  • 325.
    Hellberg, Per-Erik
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zhang, Shi-Li
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Radamson, HH
    Kaplan, W
    Threshold voltage control for PMOSFETs using an undoped epitaxial Si channel and a p(+)-SixGe1-x gate2000In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 44, no 11, p. 2085-2088Article in journal (Refereed)
    Abstract [en]

    This paper examines experimentally the performance of PMOSFETs with an undoped epitaxial Si channel in combination with a p(+)-SixGe1-x gate electrode. The channel doping profiles were made using shallow As-implantation followed by selective epitaxy of undoped Si to different thicknesses of 40, 80 and 120 nm. The p(+)-SixGe1-x gate with different values of x was used to tailor the threshold voltage. The transconductance and saturation current were found to increase and the threshold voltage to decrease with increasing thickness of the undoped Si channel for the same gate material. Increasing Ge content in the p(+)-SixGe1-x gate resulted in an increased threshold voltage. Compared to the p(+)-Si gate, the threshold voltage was increased by 0.15 and 0.35 V with a p(+)-Si0.79Ge0.21 and p(+)-Si0.53Ge0.47 gate, respectively, independently of the Si channel thickness. Therefore, the use of a p(+)-SixGe1-x gate introduces an extra degree of freedom when designing the channel for high performance PMOSFETs.

  • 326.
    Hellström, Sten
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    A reliability study of electronic components and electret foils, including latent failures due to submission to electrostatic discharges in a historical retrospective2003Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    This thesis deals with the reliability and life-time ofelectronic components and ways to determine these factors.Plastic encapsulated and open test circuits were assessed atdifferent humidity and temperature conditions. From the resultsan acceleration factor could be derived using the Arrheniusrelation. This factor is used to determine failure rates atdifferent drift conditions under accelerated test conditions. Aformula for the factor containing both relative humidity andtemperature could be established and was found to hold also formeasurements published by others.

    Electrostatic discharge (ESD) transients were studiedexperimentally and by simulation with good agreement. A verysensitive method to detect latent failures of two kinds wasintroduced by nonlinearity measurements utilizing the thirdharmonic of a test signal. The ESD-susceptibility dependence ondesign and technology is shown and can be used to improvebuilt-in reliability.

    Influences in the performance of semiconductor devices fromdefects like fixed charges and ions were interpreted for thefirst time by simulation using a 2D- finite element componentprogram. Significant results gave an application to a MOSFETdevice showing parameter derating, especially the change of thethreshold value. A short description of later development insimulation methods with new, more powerful tools improvingcomponent performance and reliability is given.

    Charged thin films of Teflon, so calledelectrets, are used as microphone membranes. Theelectret voltage is a suitable reliability factor. Fromexperimental results a mathematical relation including thetemperature was established for the rate of decay of theelectret voltage with time. A method to charge the electretswith radioactive sources is outlined and described in apatent.

    Finally an attempt was done to analyze the reliability ofthin film circuits by mathematical methods. Bell LabsintroducedRC-feedback filters realized in tantalum thin filmtechnology. The phase shift of the filter is about π or180°. A mathematical apparatus was developed to calculatethe change in frequency and attenuation from small componentvariations in resistors and capacitors. First and higher ordercorrections were derived, using expansion by the Taylor seriesfor the higher order.

    Keywords:reliability, failure mechanism, accelerationtests, ESD, latent failure, plastic encapsulation, electret,thin film

  • 327.
    Hemani, Ahmed
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Interactive Design Space Exploration1993In: Scheduling and Binding in high-level synthesis system - SYNT, 3rd Jessi (AC-8) Workshop, 1993Conference paper (Refereed)
  • 328.
    Hemani, Ahmed
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Novel Estimation Technique for High-level Synthesis Systems1993In: First Asian Pacific Conference on Hardware Description Languages, Standards & Applications, 1993Conference paper (Refereed)
  • 329.
    Hemani, Ahmed
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Self-organization and its application to binding1993In: Proceedings of the 6th International conference on VLSI Design, 1993Conference paper (Refereed)
  • 330.
    Hemani, Ahmed
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Self-organizing Binder1992In: Proc. of NORCHIP, 1992Conference paper (Refereed)
  • 331.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Deb, A. K.
    Oberg, J.
    Postula, A.
    Lindqvist, D.
    Fjellborg, B.
    System level virtual prototyping of DSP SOCs using grammar based approach2000In: Design automation for embedded systems, ISSN 0929-5585, E-ISSN 1572-8080, Vol. 5, no 04-mar, p. 295-311Article in journal (Refereed)
    Abstract [en]

    As we move from algorithm on a chip to system on a chip era, the design bottleneck is shifting from individual DSP functions to global control that composes a system from these functions. The practice in industry suffers from global control entering the design flow too late, discontinuity between functional modeling and implementation phase and mixing data flow with global control. MASIC-Maths to ASIC-is a methodology proposed in this paper that targets DSP SOCs and addresses these issues. Global control is specified in a grammar notation and integrates the output of functional modeling phase, the DSP functions, by referencing them. A virtual prototype is automatically built from such a specification that models the global control in VHDL and cosimulates with the DSP functions in C from the functional modeling phase. A highly efficient verification methodology based on separating the verification of global control from DSP functions is proposed. A smooth path to cycle true implementation is possible using either behavioral synthesis, IPs for the DSP functions or manual implementation. Experiments using realistic examples like GSM base band processing, rake receiver and some smaller examples have been carried out to quantify the benefits of MASIC.

  • 332.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Lazraq, T.
    Postula, Adam
    Department of CSEE, University of Queensland.
    Svantesson, Bengt
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Tenhunen, Hannu
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Design of Operation and Maintenance Part of the ATM Protocol1996In: Journal on Communications, Hungarian Scientific Society for Telecommunications, special issue on ATM networks, p. 34-39Article in journal (Refereed)
  • 333.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mokhtari, Mehran
    KTH, Superseded Departments, Electronic Systems Design.
    Isoaho, Jouni
    Tampere University of Technology, Signal Processing Laboratory.
    Tenhunen, Hannu
    KTH, Superseded Departments, Electronic Systems Design.
    A structure of modern VLSI curriculum1994In:  , 1994, p. 204-208Conference paper (Refereed)
    Abstract [en]

    This paper describes the restructuring of VLSI education at Royal Institute of Technology, Sweden. Changing needs of industry, advances in technology and design methodology has required a significant reorganisation of VLSI education with emphasis on system issues. This restructuring is not viewed as a one step process, rather as a continuous process including close interaction between education and research

  • 334.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Postula, Adam
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Cell placement by self-organisation1990In: Neural Networks, ISSN 0893-6080, E-ISSN 1879-2782, Vol. 3, no 4, p. 377-383Article in journal (Refereed)
  • 335.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Postula, Adam
    Department of CSEE, University of Queensland.
    NISCHE: Neural net inspired scheduling algorithm1989In: Fourth international workshop on high level synthesis, 1989Conference paper (Refereed)
  • 336.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Postula, Adam
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Optimization of Controller in HLS over the controller and datapath boundary1993Conference paper (Refereed)
  • 337.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Postula, Adam
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Scheduling by Self-organization1990In: Proceedings of IJCNN’90, 1990Conference paper (Refereed)
  • 338.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Postula, Adam
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hungenahally, S.
    Self-organization based scheduling and binding algorithm for High-level Synthesis of digital circuits1993In: 16th Australian Computer Science Conference, 1993Conference paper (Refereed)
  • 339.
    Hemani, Ahmed
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Tenhunen, Hannu
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mokhtari, Mehran
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hellberg, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Restructuring VLSI Education at Royal Inst. Of Technology1993Conference paper (Refereed)
  • 340. Henry, A.
    et al.
    Janson, Martin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janzen, E.
    Properties of the bound excitons associated to the 3838 angstrom line in 4H-SiC and the 4182 angstrom line in 6H-SiC2004In: SILICON CARBIDE AND RELATED MATERIALS 2003, PRTS 1 AND 2 / [ed] Madar, R; Camassel, J, 2004, Vol. 457-460, p. 549-554Conference paper (Refereed)
    Abstract [en]

    We report the results of a photoluminescence (PL) study of the properties of a bound-exciton (BE) line observed at about 3838Angstrom in the PL spectrum of 4H-SiC and at 4182Angstrom in 6H-SiC. Both spectra have almost the same phonon structure containing localized modes. The temperature dependences show that the no-phonon (NP) lines have at least three excited states higher in energy. The most intense high-temperature lines do not split under applied magnetic field whereas the low temperature lines split into three components when the magnetic field is applied in the direction perpendicular to the c-axis. Time-resolved PL reveals several hundreds microseconds long lifetime at 2K with a second component an order of magnitude faster. Our results can be explained by an excitonic recombination at an isoelectronic center but are in conflict with the previous association of the 3838Angstrom line in 4H-SiC with the recombination of the bound exciton at the neutral shallow boron acceptor. The luminescence in our samples is increasing with excitation time. This luminescence is not observed from our as-grown material but appears after SIMS analysis. The as-grown material used was intentionally boron-doped epilayers.

  • 341. Hessmo, B.
    et al.
    Soderholm, J.
    Björk, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Entangled states in interferometry2002In: Acta Physica Polonica. A, ISSN 0587-4246, E-ISSN 1898-794X, Vol. 101, no 1, p. 37-46Article in journal (Refereed)
    Abstract [en]

    We show how some entangled quantum states can be used to improve interferometric measurements. We describe why Schrodinger-cat states are very sensitive to relative-phase shifts and why relative-phase states as described by A. Luis and L.L. Sanchez-Soto resolve the interval [0, 2pi] well. We also describe how the quantum concept of well-defined relative-phase and the classical visibility of an interference pattern are related.

  • 342.
    Hessmo, Björn
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Usachev, P.
    Heydari, Hoshang
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Experimental demonstration of single photon nonlocality2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 18Article in journal (Refereed)
    Abstract [en]

    In this Letter we experimentally implement a single photon Bell test based on the ideas of S. Tan et al. [Phys. Rev. Lett. 66, 252 (1991)] and L. Hardy [Phys. Rev. Lett. 73, 2279 (1994)]. A double homodyne measurement is used to measure correlations in the Fock space spanned by zero and one photons. Local oscillators used in the correlation measurement are distributed to two observers by copropagating it in an orthogonal polarization mode. This method eliminates the need for interferometrical stability in the setup, consequently making it a robust and scalable method.

  • 343. Heydari, H.
    et al.
    Björk, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Sanchez-Soto, L. L.
    Measurable entanglement criterion for two qubits2003In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 68, no 6Article in journal (Refereed)
    Abstract [en]

    We propose a directly measurable criterion for the entanglement of two qubits. We compare the criterion with other criteria, and we find that for pure states, and some mixed states, it coincides with the state's concurrence. The measure can be obtained with a Bell-state analyzer and the ability to make general local unitary transformations. However, the procedure fails to measure the entanglement of a general mixed two-qubit state.

  • 344.
    Heydari, Hoshang
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Quantum entanglement: theory and an experiment2004Doctoral thesis, comprehensive summary (Other scientific)
  • 345.
    Heydari, Hoshang
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Entanglement measure for general pure multipartite quantum states2004In: Journal of Physics A: Mathematical and General, ISSN 0305-4470, E-ISSN 1361-6447, Vol. 37, no 39, p. 9251-9260Article in journal (Refereed)
    Abstract [en]

    We propose an explicit formula for a measure of entanglement of pure multipartite quantum states. We discuss the mathematical structure of the measure and give a brief explanation of its physical motivation. We apply the measure on some pure, tripartite, qubit states and demonstrate that, in general, the entanglement can depend on what actions are performed on the various subsystems, and specifically if the parties in possession of the subsystems cooperate or not. We also give some simple but illustrative examples of the entanglement of four-qubit and m-qubit states.

  • 346.
    Heydari, Hoshang
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mutual first-order coherence of phase-locked lasers2004In: Journal of Optics B-Quantum and Semiclassical Optics, ISSN 1464-4266, E-ISSN 1741-3575, Vol. 6, no 1, p. 46-53Article in journal (Refereed)
    Abstract [en]

    We argue that (first-order) coherence is a relative, and not an absolute, property. It is shown how feedforward or feedback can be employed to make two (or more) lasers relatively coherent. We also show that after the relative coherence is established, the two lasers will,stay relatively coherent for some time even if the feedforward or feedback loop has been turned off, enabling, e.g., demonstration of unconditional quantum teleportation using lasers.

  • 347.
    Hidell, Markus
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hagsand, Olof
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Sjödin, Peter
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Distributed Control for Decentralized Modular Routers2004In: 2nd Swedish National Computer Networking Workshop, SNCNW 2004, Karlstad, Sweden, 2004, p. 9-13Conference paper (Refereed)
    Abstract [en]

    The requirements on IP routers continue to increase, both from the control plane and the forwarding plane perspectives. To improve scalability, flexibility, and availability we investigate new ways to build future routers. This paper presents a system model of a decentralized and modular router architecture. Design alternatives and implementation aspects are discussed, and a system implementation is presented.

  • 348.
    Hillkirk, Leonardo M.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Dynamic surface temperature measurements in SiC epitaxial power diodes performed under single-pulse self-heating conditions2004In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 48, no 12, p. 2181-2189Article in journal (Refereed)
    Abstract [en]

    Semiconductor devices development, design and optimization require the use of computer simulation tools able to predict the entire device safe operating area (SOA), something that it is not always possible due to limitations in some of the physical models in predicting certain properties of device operation under extreme conditions (i.e. high carrier injection levels and high temperature). In order to improve our understanding of device operation under these extreme conditions experimental data of the dynamic IV characteristics and temperature time evolution and space distribution are required. The experimental data obtained are then used in the development of improved physical models and simulation tools. In this work, dynamic surface temperature measurements as a function of current pulse peak density and length were performed on SiC-PiN epitaxial power diodes. The measurements were carried out using an infrared (IR) microscope developed in our lab capable of measuring space and time surface temperature distributions in semiconductor devices operating under self-heating conditions [Solid State Electron 2001;45(12):2057]. The minimum detected spot size is 15 mum, while the signal raising time is detector limited to about 1 mus. The lowest detectable temperature increment is at least 10 degreesC over room temperature. Using this instrument, dynamic thermal phenomena in 4.5 kV SiC-PiN epitaxial power diodes [Mater Sci Forum 2001;353-356:727] subjected to I ms long 100-6000 A/cm(2) and 0.1-5 ms long 3000 A/cm(2) current pulses have been studied. The possibility of obtaining dynamic surface temperature information from SiC electronic devices operating under self-heating conditions with time constants in the order of ms is demonstrated.

  • 349.
    Hitana, Tahar
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Deb, Abhijit Kumar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Bridging concurrent and non-concurrent error detection in FIR filters2004In: 22ND NORCHIP CONFERENCE, PROCEEDINGS, NEW YORK: IEEE , 2004, p. 75-78Conference paper (Refereed)
    Abstract [en]

    Maintaining high reliability in fault detection is a prominent concern in case of life critical missions. In this paper, we describe how the invariant-based technique has been improved and extended. It is shown that the detection time latency can be considerably reduced. In order to widen the fault coverage and fully control the detection time, a cost effective nonconcurrent error detection scheme is proposed. The results indicate that, for any specified checking period, 100% non-concurrent error detection is possible.

  • 350.
    Hjelm, Mats
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Monte Carlo Simulations of Homogeneous and Inhomogeneous Transport in Silicon Carbide2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The importance of simulation is increasing in the researchon semiconductor devices and materials. Simulations are used toexplore the characteristics of novel devices as well asproperties of the semiconductor materials that are underinvestigation, i.e. generally materials where the knowledge isinsufficient. A wide range of simulation methods exists, andthe method used in each case is selected according to therequirements of the work performed. For simulations of newsemiconductor materials, extremely small devices, or deviceswhere non-equilibrium transport is important, the Monte Carlo(MC) method is advantageous, since it can directly exploit themodels of the important physical processes in the device.

    One of the semiconductors that have attracted a lot ofattraction during the last decade is silicon carbide (SiC),which exists in a large number of polytypes, among which3C-SiC, 4H-SiC and 6H-SiC are most important. Although SiC hasbeen known for a very long time, it may be considered as a newmaterial due to the relatively small knowledge of the materialproperties. This dissertation is based on a number of MCstudies of both the intrinsic properties of different SiCpolytypes and the qualities of devices fabricated by thesepolytypes. In order to perform these studies a new full-bandensemble device MC simulator, the General Monte CarloSemiconductor (GEMS) simulator was developed. Algorithmsimplemented in the GEMS simulator, necessary when allmaterial-dependent data are numerical, and for the efficientsimulation of a large number of charge carriers in high-dopedareas, are also presented. In addition to the purely MC-relatedstudies, a comparison is made between the MC, drift-diffusion,and energy-balance methods for simulation of verticalMESFETs.

    The bulk transport properties of electrons in 2H-, 3C-, 4H-and 6H-SiC are studied. For high electric fields the driftvelocity, and carrier mean energy are presented as functions ofthe field. For 4H-SiC impact-ionization coefficients,calculated with a detailed quantum-mechanical model ofband-to-band tunneling, are presented. Additionally, a study oflow-field mobility in 4H-SiC is presented, where the importanceof considering the neutral impurity scattering, also at roomtemperature, is pointed out.

    The properties of 4H- and 6H-SiC when used in short-channelMOSFETs, assuming a high quality semiconductor-insulatorinterface, are investigated using a simple model for scatteringin the semiconductor-insulator interface. Furthermore, theeffect is studied on the low and high-field surface mobility,of the steps formed by the common off-axis-normal cutting ofthe 4H- and 6H-SiC crystals. In this study an extension of theprevious-mentioned simple model is used.

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