Upload
others
View
26
Download
5
Embed Size (px)
Citation preview
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
Sourabh Khandelwal MOS-AK 2014 5
Analytical Solution of Schrӧdiger’s & Poisson’s
SP-Based Id Ig & ChargeModelReal Device effects included
Noise Model, Trapping EffectsModel, Self-Heating
2-DEG ChargeFermi-level (Ef),Surface-potential (SP)
Accurate I-V and C-VPhysical parametersDIBL, Rs, VS, ...
DC, AC, TransientHarmonic Simulations,Noise
Sourabh Khandelwal MOS-AK 2014 6
Surface-Potential Modeling
• Basic device equations are transcendental in nature
• We divide variation of Ef with Vg into regions to develop fully analytical expression
• Regional models are combined in one analytical expression
• No fitting parameters introduced
Surface-Potential Model
Sourabh Khandelwal MOS-AK 2014 7
/ , / /s d f s d s dE Vψ = +S. Khandelwal et al. IEEE TED vol. 59, no. 10, 2012
Sourabh Khandelwal MOS-AK 2014 8
Drain-Current Model
• Core Drain Current Model
• Velocity-Field relation and mobility-degradation
Access Region Resistance
• Non-linear model for access region resistances• Accounts for velocity saturation in access region
Sourabh Khandelwal MOS-AK 2014 9
S DG
AlGaN
GaN
G
DS
Intrinsic
Rd = f(Vg, Vd)Rs = f(Vg, Vd)
Self-Heating Model
Sourabh Khandelwal MOS-AK 2014 10
Temperature
Rth CthPd
Self-Heating effect model in ASM-HEMT
TemperatureDependent
Parameters, calculations in
the model
Sourabh Khandelwal MOS-AK 2014 11
Intrinsic Charge Modeling
• Surface-Potential Based Charge Expressions• Consistent I-V and C-V calculations
• Ward-Dutton Partioning for source and drain charges
( )
( )
( )
0
0
0
, .
, .
1 , .
L
g s g x
L
d s g x
L
s s g x
Q Wqn V V dx
xQ Wqn V V dxL
xQ Wqn V V dxL
=
=
= −
∫
∫
∫
Charge Conservation
Intrinsic Charge Modeling
Sourabh Khandelwal MOS-AK 2014 12
Intrinsic Charge Modeling
• Analytical Expressions for all terminal charges
• All Device Capacitances:
𝐶𝐶𝑖𝑖𝑖𝑖 =𝜕𝜕𝜕𝜕𝜕𝜕𝜕𝜕𝜕𝜕𝜕𝜕
• 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
• Forward Gate Current
Sourabh Khandelwal MOS-AK 2014 14
Surface-Potential-Based
Flicker Noise Model
Sourabh Khandelwal MOS-AK 2014 15L= 0.7 um GaN Device
L=0.35 um GaAs device
Thermal Noise Model
Sourabh Khandelwal MOS-AK 2014 16
Model Inputs and Parameters
Sourabh Khandelwal MOS-AK 2014 17
• Physical Constants– D, q, ...
• Simulation Conditions– Vg, Vd, T...
• Device Dimensions– L, W, d, ..
• Physically-Linked Model Parameters
Parameter Physical MeaningU0 Low field MobilityUA Mobility degradation parameterUB Mobility degradation parameterVOFF Cut-off Voltage of DeviceVSAT Saturation VelocityRTH Thermal ResistanceDIBL DIBL effect parameterVOFFT Temperature dependence of VoffUTE Mobility dependence of mu0RS Source Side Resistance
RD Drain Side Resistance... …
Model Parameter Extraction
Sourabh Khandelwal MOS-AK 2014 18
Set L, W, NF, TbarDevice Dimensions
Obtain VOFF, NF, CDSCD, ETA from log-IDVG, LINEAR
And Saturation
Obtain U0, UA, UB and RDS from IDVG-LIN
Obtain VSAT, Improve ETAFrom LINEAR IDVG
Obtain LAMBDA, Improve VSAT, ETA from IDVD
Temperature Parameters
Capacitance Modeling
Noise Modeling
Extraction flow similar to standard physics-based models Parameters linked to physical effects
GaN Model Results DC I-V
Sourabh Khandelwal MOS-AK 2014 19
Calibration for Channel Lengths L = 1 um and L = 0.7 um
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
VD1 VD2
VD3
VD4VD5
GMVG for various VD
VD1
VD2
VD3
VD4VD5
GM’VG for various VD
VD1 VD2 VD3
VD4 VD5
GM’’VG for various VD
VD1VD2 VD3
VD4 VD5
Smooth, Continuous and Accurate ID and its derivatives
S-Parameter Data Fitting Results
S-parameter Fitting Vs Frequency@ Bias1
|S11|
|S12|
|S22|
|S21|
S-parameter Fitting Vs Frequency@ Bias1
Ph-S11
Ph-S12
Ph-S22
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-S11Ph-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
Sourabh Khandelwal MOS-AK 2014 34
Accurate Pout and PIM3 prediction by model at various bias points
S. Khandelwal et al., IEEE MTT, vol. 61, no. 9, 2013
Model Quality: GummelSymmetry Test
Sourabh Khandelwal MOS-AK 2014 35
Symmetric, Continuous and Smooth Model Behavior
Model Quality: Capacitances
Sourabh Khandelwal MOS-AK 2014 36
Model Passes Gummel AC Symmetry Tests
GS GDcg
GS GD
C CC C
δ −=
+𝛿𝛿𝑐𝑐𝑐𝑐𝑐𝑐 =
𝐶𝐶𝑆𝑆𝑆𝑆 − 𝐶𝐶𝐷𝐷𝐷𝐷𝐶𝐶𝑆𝑆𝑆𝑆 + 𝐶𝐶𝐷𝐷𝐷𝐷
Model Quality: Capacitances
Sourabh Khandelwal MOS-AK 2014 37
Correct Physical behavior of capacitances
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
References1. 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