ASM GaN HEMT: Advanced SPICE Model for GaN HEMTs Sourabh Khandelwal, T. A. Fjeldly, B. Iniguez, Y. S. Chauhan, S. Ghosh, A. Dasgupta MOS-AK 2014 Sourabh Khandelwal MOS-AK 2014 1
Outline ASM-HEMT Model Background Model Description Overview 2-DEG Charge Density & Surface-Potential Model Drain-Current, Gate-Current Model Charge and Capacitance Model Flicker Noise and Thermal Noise Models Model Results Model Parameter Extraction DC I-V Results: Drain and Gate-Current On industry data S-parameter validation for multiple DC bias points Power Sweep Harmonic Balance Simulation Results Model Quality Testing Gummel DC and AC Symmetry Physical behavior of capacitances Conclusions Sourabh Khandelwal MOS-AK 2014 2
ASM-HEMT Model Background Started as PhD Thesis Work at UNIK/NTNU, Norway Sourabh Khandelwal and Prof. Tor A. Fjeldly Compact Modeling Solutions for Advanced Semiconductor Devices PhD Thesis NTNU 2013:248 EU Project COMON In Collaboration with Prof. B. Iniguez, URV Spain Prof. Yogesh S. Chauhan, IIT Kanpur Model passed into the Phase-II for standardization at the Compact Model Coalition (CMC) Two sponsor companies Sourabh Khandelwal MOS-AK 2014 3
ASM-HEMT Model Overview Schrӧdiger s & Poisson s solution for core SP calculation Drain current model includes all the important real device effects Velocity Saturation, DIBL, Mobility Degradation, Temperature effects, Non-linear access region resistances, SS degradation Gate Current Model Frenkel-Poole Mechanism Self-Heating Effect Model Model for Trapping effects Flicker Noise Model Thermal Noise Model Sourabh Khandelwal MOS-AK 2014 4
ASM-HEMT Model Overview Analytical Solution of Schrӧdiger s & Poisson s 2-DEG Charge Fermi-level (Ef), Surface-potential (SP) SP-Based I d I g & ChargeModel Real Device effects included Accurate I-V and C-V Physical parameters DIBL, Rs, VS,... Noise Model, Trapping Effects Model, Self-Heating DC, AC, Transient Harmonic Simulations, Noise Sourabh Khandelwal MOS-AK 2014 5
Surface-Potential Modeling Basic device equations are transcendental in nature We divide variation of E f with V g into regions to develop fully analytical expression Regional models are combined in one analytical expression No fitting parameters introduced Sourabh Khandelwal MOS-AK 2014 6
Surface-Potential Model ψ = E + V sd / fsd, / sd / S. Khandelwal et al. IEEE TED vol. 59, no. 10, 2012 Sourabh Khandelwal MOS-AK 2014 7
Drain-Current Model Core Drain Current Model Velocity-Field relation and mobility-degradation Sourabh Khandelwal MOS-AK 2014 8
Access Region Resistance S G AlGaN GaN D Non-linear model for access region resistances Accounts for velocity saturation in access region G Intrinsic S Rs = f(vg, Vd) D Rd = f(vg, Vd) Sourabh Khandelwal MOS-AK 2014 9
Self-Heating Model Temperature Temperature Dependent Parameters, calculations in the model Pd Rth Cth Self-Heating effect model in ASM-HEMT Sourabh Khandelwal MOS-AK 2014 10
Intrinsic Charge Modeling Surface-Potential Based Charge Expressions Consistent I-V and C-V calculations Ward-Dutton Partioning for source and drain charges L ( ) Q = Wqn V, V. dx g s g x 0 L x Q = Wqn V, V. dx ( ) d s g x L 0 L x Q = 1 Wqn ( V, V ). dx s s g x L 0 Charge Conservation Sourabh Khandelwal MOS-AK 2014 11
Intrinsic Charge Modeling Sourabh Khandelwal MOS-AK 2014 12
Intrinsic Charge Modeling Analytical Expressions for all terminal charges All Device Capacitances: CC iiii = Correct physical behavior of capacitances Parasitic Capacitances added to intrinsic capacitance model Sourabh Khandelwal MOS-AK 2014 13
Gate Current Model Reverse Gate Leakage Mechanism Frenkel-Poole Model Surface-Potential-Based Forward Gate Current Sourabh Khandelwal MOS-AK 2014 14
Flicker Noise Model L= 0.7 um GaN Device L=0.35 um GaAs device Sourabh Khandelwal MOS-AK 2014 15
Thermal Noise Model Sourabh Khandelwal MOS-AK 2014 16
Model Inputs and Parameters Physical Constants D, q,... Simulation Conditions Vg, Vd, T... Device Dimensions L, W, d,.. Physically-Linked Model Parameters Parameter U0 UA UB VOFF VSAT RTH DIBL VOFFT UTE RS RD Physical Meaning Low field Mobility Mobility degradation parameter Mobility degradation parameter Cut-off Voltage of Device Saturation Velocity Thermal Resistance DIBL effect parameter Temperature dependence of Voff Mobility dependence of mu0 Source Side Resistance Drain Side Resistance... Sourabh Khandelwal MOS-AK 2014 17
Model Parameter Extraction Extraction flow similar to standard physics-based models Parameters linked to physical effects Set L, W, NF, Tbar Device Dimensions Obtain LAMBDA, Improve VSAT, ETA from IDVD Obtain VOFF, NF, CDSCD, ETA from log-idvg, LINEAR And Saturation Temperature Parameters Obtain U0, UA, UB and RDS from IDVG-LIN Capacitance Modeling Obtain VSAT, Improve ETA From LINEAR IDVG Noise Modeling Sourabh Khandelwal MOS-AK 2014 18
GaN Model Results DC I-V Calibration for Channel Lengths L = 1 um and L = 0.7 um Sourabh Khandelwal MOS-AK 2014 19
DC Fitting Results with Industry Data Sourabh Khandelwal MOS-AK 2014 20
IDVG for various VDS VD1 VD2 VD3 VD4 VD5
Sub-threshold ID for various VD VD3 VD1 VD2 VD4 VD5
GMVG for various VD VD1 VD3 VD2 VD4 VD5
GM VG for various VD VD1 VD2 VD3 VD4 VD5
GM VG for various VD Smooth, Continuous and Accurate ID and its derivatives VD1 VD2 VD3 VD4 VD5
S-Parameter Data Fitting Results
S-parameter Fitting Vs Frequency @ Bias1 S11 S22 S12 S21
S-parameter Fitting Vs Frequency @ Bias1 Ph-S11 Ph-S22 Ph-S12 Ph-S21
S-parameter Fitting Vs Frequency @ Bias1 H21 K Max Gain
S-parameter Fitting Vs Frequency @ Bias2 S11 S22 S12 S21
S-parameter Fitting Vs Frequency @ Bias2 Ph-S11 Ph-S22 Ph-S12 Ph-S21
S-parameter Fitting Vs Frequency @ Bias2 H21 K Max-Gain
RF Power Sweep GaN Device Tuned for maximum power
Harmonic Balance Results Accurate Pout and PIM3 prediction by model at various bias points S. Khandelwal et al., IEEE MTT, vol. 61, no. 9, 2013 Sourabh Khandelwal MOS-AK 2014 34
Model Quality: Gummel Symmetry Test Symmetric, Continuous and Smooth Model Behavior Sourabh Khandelwal MOS-AK 2014 35
Model Quality: Capacitances Model Passes Gummel AC Symmetry Tests δ cg = C C GS GS C + C GD GD δδ cccccc = CC SSSS CC DDDD CC SSSS + CC DDDD Sourabh Khandelwal MOS-AK 2014 36
Model Quality: Capacitances Correct Physical behavior of capacitances Sourabh Khandelwal MOS-AK 2014 37
Conclusions Physics-based Model for GaN HEMTs presented Schrodinger s and Poisson s based surface-potential analytical calculation Drain and Gate Current Charges and Capacitances Model Real Device effects (CLM, DIBL, Self-Heating etc.) included Flicker Noise and Thermal Noise models Excellent Agreement with industry quality measured data DC, S-parameters, Power Sweep Model passes important quality test Gummel Symmetry, AC Symmetry, Harmonic Balance etc. Sourabh Khandelwal MOS-AK 2014 38
References 1. Sourabh Khandelwal, Chandan Yadav, Shantanu Agnihotri, Yogesh Singh Chauhan, Arnaud Curutchet, Thomas Zimmer, Jean-Claude Dejaeger, Nicolas Defrance, and Tor A. Fjeldly, "A robust surface-potential-based compact model for GaN HEMT IC design", IEEE Trans. Electron Devices, vol. 60, no. 10, pp. 3216-3222, 2013 2. Sourabh Khandelwal, and Tor A. Fjeldly, "Analysis of Drain-Current Nonlinearity Using Surface-Potential-Based Model in GaAs phemts", IEEE Trans. Microwave Theory and Tech., vol. 61, no. 9, pp. 3265-3270, Sep. 2013. 3. Sourabh Khandelwal, Yogesh Singh Chauhan and Tor A. Fjeldly, "Analytical modeling of surface-potential and intrinsic charges in AlGaN/GaN HEMT devices", IEEE Trans. Electron. Devices vol. 59, no. 10 pp. 2856-2860, Oct. 2012. 4. Sourabh Khandelwal, Nitin Goyal, and Tor A. Fjeldly, "A Physics based analytical model for 2-DEG charge density in AlGaN/GaN HEMT devices", IEEE Trans. Electron Devices vol. 58, no. 10 pp. 3622-3625, Oct. 2011. 5. S. Khandelwal and Tor A. Fjeldly, "A surface-potential-based compact model for study of non-linearities in AlGaAs/GaAs HEMTs", Proc. Compound Semiconductor IC Symp., pp. 1-4, Oct. 2012, San Diego, USA. 6. A. Dasgupta, S. Khandelwal, and Y. S. Chauhan, Compact Modeling of flicker noise in HEMTs JEDS 2014. 7. S. Ghosh, A. Dasgupta, S. Khandelwal, et al. Surface-potential-based compact modeling of gate current in AlGaN/GaN HEMTs IEEE TED 2014 Sourabh Khandelwal MOS-AK 2014 39
Thank You for Attention! Sourabh Khandelwal MOS-AK 2014 40