Advanced Semiconductor Device Simulation at TU Wien

Transcription

1 Advanced Semiconductor Device Simulation at TU Wien MINOS EURONET Workshop Sozopol, Bulgaria, Sept. 21, 2007 Vassil Palankovski Advanced Materials and Device Analysis Group Inst. for Microelectronics, TU Vienna, Austria

2 The Institute for Microelectronics Founded in 1988 Staff 1 full professor 3 associate professors 3 scientific employees 3 non-scientific employees 4 postdoc researchers 15 scientific co-workers Research cooperations with national and international semiconductor industry EU research projects National projects FWF Christian-Doppler-Lab for Integrated Circuits START - AMADEA Group

3 Overview Motivation Research topics and workplan of START Scientific achievements and future research International and national co-operations CV

4 Motivation Thorough study of novel semiconductor materials and devices Solve critical design issues by means of simulation save experimental effort Develop new optimized electron device structures Optimization goals: high power, high breakdown, high speed, low leakage Optimization targets: geometry, doping, material composition, material system

5 Research Topics and Workplan Topics Topics ) Strained Silicon _ 1) Strained Silicon _ 5) PbTe, PbSe, Bi Te 2 3 _ 2) _ 6) InP GaAs 2) GaAs _ GaSb Workplan (in person.years) Work done 3) GaN 3) GaN 7) Compact Modeling _ Work planned Summary 4) QMC 4) QMC _ 8) Solar Cells _ Total: 24 = 6Y x 4P Done: ~8 Planned: >16

6 Simulation Software Tools Existing tools extended in START VMC: Bulk Monte Carlo simulator Minimos-NT: a generic 2D/3D device/circuit simulator New tools initiated in START EMC: 2D Ensemble Monte Carlo device simulator QEMC: 1D/2D Quantum Ensemble Monte Carlo device simulator Applications Advanced materials: strained Si/SiGe, various III-Vs, focus on III-Nitrides, planned are III-Antimonides, IV-VI materials, novel dielectrics Advanced devices: HBTs, HEMTs, quantum wires, solar cells

7 Low-Field Mobility in Strained Si Electron mobility vs. Ge content Electron mobility vs. doping Electron mobility [cm 2 /Vs] MC data N A =1e14 cm 3 (µ par ) MC data N A =1e14 cm 3 (µ perp ) MC data N A =1e18 cm 3 (µ par ) MC data N A =1e18 cm 3 (µ perp ) model N A =1e14 cm 3 (µ par ) model N A =1e14 cm 3 (µ perp ) model N A =1e18 cm 3 (µ par ) model N A =1e18 cm 3 (µ perp ) piezo model (µ par ) Electron mobility [cm 2 /Vs] µ par µ perp MC data Si (min) MC data Si (maj) exp. data (min) exp. data (maj) model (maj) model (min) MC data SSi (min) Ge content y [ ] Impurity concentration [cm 3 ]

8 Modeling of GaAs Electron velocity at ultrahigh electric fields Ultrafast switching: Vce vs. time Electron drift velocity [10 7 cm/s] exp. data MC simulation 1e15 model MMNT 1e15 MC data 4 valleys Collector Emitter Voltage [V] exp. data simulation NDM simulation PDM 4 valleys Electric field [kv/cm] Time [ns]

9 Electron Mobility GaN Low-field electron mobility vs. carrier concentration Electron scattering rates vs. concentration Low field electron mobility [cm 2 /Vs] exp. collection Chin 1994 exp. Gaskill 1995 exp. coll. Schwierz 1996 exp. coll. Schwierz 1997 exp. Koehler 2003 exp. Zanato 2004 MC this work, wurtzite v s MC this work, cubic v s Scattering rates [s 1 ] Ionized impurity Acoustic deformation potential Piezoelectric acoustic phonon Polar optical phonon 92 mev Carrier concentration [cm 3 ] Carrier concentration [cm 3 ]

10 Electron Mobility InN Low-field electron mobility vs. carrier concentration Electron scattering rates vs. concentration Low field electron mobility [cm 2 /Vs] Tansley 1984 exp. Yamamoto 1998 exp. Dmowsky 2005 exp. Polyakov 2006 exp. Thakur 2006 exp. Chin 1994 sim. Polyakov 2006 sim. this work, m Γ1 =0.04m 0 this work, m Γ1 =0.11m 0 Scattering Rates [1/s] Ionized Impurity Acoustic. def. Pot. Polar Optical Piezo Carrier concentration [cm 3 ] Carrier concentration [cm 3 ] Presented at 13th Intl.Conf. on Narrow Gap Semiconductors: S. Vitanov and V. Palankovski, MC Study of Transport Properties of InN

11 AlGaN/GaN HEMT: Layer Structure l g l FP Field plate Gate Source GaN Cap AlGaN Barrier δ doping AlGaN Spacer GaN Channel SiN passivation Drain GaN Buffer

12 Field Plate Optimization Field plate variation Gate length variation Electric Field [V/cm] 2.2e e e e e e e e e e+05 Gate 2.0e x [um] l FP =200nm l FP =400nm l FP =600nm l FP =800nm l FP =1µm Electric Field [V/cm] 2.2e e e e e e e e e e e x [um] Presented at 29th IEEE Compound Semiconductor IC Symposium: V. Palankovski, S. Vitanov, and R. Quay,: Field-Plate Optimization of AlGaN/GaN HEMTs l g =150nm l g =300nm l g =500nm l g =600nm l g =800nm

13 2D Wigner Function Simulations Density of classical carriers Density of Wigner carriers Y [nm] The simulation lasted 10 days on a 3.4 GHz PC X [nm]

14 Modeling of InP and GaSb InP/InGaAs/InP HBT InP/GaAsSb/InP HBT Emitter InGaAs n+ InP(InAlAs) Emitter n+/n InGaAs Base p+ Base SiN Passivation Emitter InGaAs n+ InP Emitter n GaAsSb Base p+ Base SiN Passivation InGaAs(P) Launcher n InP Collector n InP Collector n Collector Collector InGaAs Subcollector n+ InGaAs Subcollector n SI InP Substrate Symmetry axis SI InP Substrate Symmetry axis

15 Modeling of PbTe, PbSe, Bi 2 Te Low field electron mobility [cm 2 /Vs] α=2.0 α=3.0 α=5.26 exp. data Allgaier58 exp. data Ravich71 exp. data Ueta97 MC data 77K MC data 300 K Carrier concentration [cm 3 ] Presented at 13th Intl.Conf. on Narrow Gap Semiconductors: V. Palankovski, M. Wagner, W. Heiss, Monte Carlo Simulation of Electron Transport in PbTe

16 Modeling of Solar Cells Electron concentration negative surface charges Electron concentration positive surface charges y [um] x [um] <1e+05 Presented at 21st European Photovoltaic Solar Energy Conference >1e+20 1e+19 1e+18 1e+17 1e+16 1e+15 1e+14 1e+13 1e+12 1e+11 1e+10 1e+09 1e+08 1e+07 1e+06 y [um] x [um] P. Vitanov, S. Vitanov, V. Palankovski, Two-Dimensional Analysis of the Back-Side Contacts of Thin Silicon Solar Cells >1e+20 1e+19 1e+18 1e+17 1e+16 1e+15 1e+14 1e+13 1e+12 1e+11 1e+10 1e+09 1e+08 1e+07 1e+06 <1e+05

17 Scientific Co-operations Module 1 (SSi): Univ. der Bundeswehr Munich (Germany) Module 2 (GaAs): Univ. of Manchester (UK), Univ. of Oulu (Finland) Module 3 (GaN): Fraunhofer Inst. Freiburg IAF (Germany); NXP (the Netherlands); Infineon Technologies (Germany), Inst. for Solid-State Electronics, TU Vienna Module 4 (QMC): Arizona State Univ. (USA), Univ. of Modena (Italy), Univ. of Reading (UK), Bulgarian Academy of Sciences CLPP, Univ. of Glasgow (UK), Inst. for Computational Physics, TU Graz Module 5 (InP): Fraunhofer Inst. Freiburg IAF (Germany) Module 6 (PbTe): Johannes Kepler University Linz Module 7 (Compact Modeling): TU Dresden (Germany), TU Sofia (Bulgaria) Module 8 (Solar Cells): Bulgarian Academy of Sciences SENES

18 Curriculum Vitae 1993 Master s degree in electronics, TU Sofia, Bulgaria Commercial manager, Siemens Public Networks, Sofia Doctorate Program, Technical University Vienna Free researcher, Siemens Corporate Research, Munich 2000 Visiting researcher at LSI Logic, Milpitas, CA, USA 2000 Doctoral degree in technical sciences, TU Vienna PostDoc at the TU Vienna (FWF and SRC Projects) 2004 Book: Analysis and Simulation of Heterostructure Devices 2004 Visiting researcher and lecturer, TU Sofia (ÖFG Project) 2004 START Prize - Simulation of Advanced Semiconductor Devices Technology development engineer, Infineon Technologies, Villach since 2005 Head of the AMADEA Group, Inst. for Microelectronics, TU Vienna 2006 Nomination for Viennovation-Award 2007 Habilitation