ASM-HEMT Model for GaN RF and Power Electronic Applications: Overview and Extraction
Sheikh Aamir Ahsan
Sudip Ghosh
Yogesh Singh Chauhan
IIT Kanpur
Sourabh Khandelwal
UC Berkeley
MA Long
Keysight Technologies
June 27, 2016
PageContents
โ ASM-HEMT Model Overview
โ Parameter Extraction
โข DC Model
โข Field Plate Capacitance Model
โข RF Small Signal Model
โ Summary
MOS-AK Workshop Shanghai
2016 2
Page
GaN HEMT Model Standardization Effort in CMC
โ Compact Model Coalition โ an industry body that standardizes and promotes SPICE
models for semiconductor devices as well as compiled modeling interface
โ Dedicated workgroup for GaN HEMT model standardization launched in Year 2011
โ Standardization process
โข Phase I completed: solicitation of models and presentation to CMC.
โข Phase II completed: shortlisted candidate models being examined against
fundamental requirements and being fitted to measurement data for CMC evaluation
โข Phase III is ongoing: evaluation on runtime, convergence, operability, etc.
- ASM-HEMT
- MVSG
โข Phase IV: ballot for standardization (targeting at the end of 2016)
MOS-AK Workshop Shanghai 2016 3
* Compact Model Coalition, https://www.si2.org/cmc_index.php* Keith Green, http://www.eetimes.com/author.asp?section_id=36&doc_id=1324925
Page
ASM-HEMT Model Overview
MOS-AK Workshop Shanghai 2016 4
Transcendental
๐๐ = ๐ท๐๐กโ ln ex๐๐ธ๐ โ ๐ธ0๐๐กโ
+ 1 + ln ex๐๐ธ๐ โ ๐ธ1๐๐กโ
+ 1
๐ธ0 = ๐พ0๐๐ 2/3
๐ธ1 = ๐พ1๐๐ 2/3
๐๐ =๐
๐๐๐๐๐ โ ๐ธ๐ โ ๐๐ฅ
๐ธ๐,๐ข๐๐๐๐๐๐ = ๐๐๐ โ2๐๐กโ ln 1 + ๐
๐๐๐2๐๐กโ
1
๐ป ๐๐๐ , ๐+๐ถ๐๐๐ท
๐โ๐๐๐2๐๐กโ
๐ = ๐ธ๐ + ๐๐ฅ
Page
ASM HEMT Model Overview
MOS-AK Workshop Shanghai 2016 5
Intrinsic Charges
Incorporating Realistic device effects
Page
List of Parameters I
MOS-AK Workshop Shanghai 2016 6
Core Model Parameters
I
I
I
I
Page
List of Parameters II
Access Region and Temperature Parameters
MOS-AK Workshop Shanghai 2016 7
I
I
I
Page
Parameter Extraction I
MOS-AK Workshop Shanghai 2016 8
Id-Vgs (Linear) Id-Vgs (Log)
Id-Vg Linear and Log Scale (Linear Vd Condition)
Id-Vgs (Linear)
VOFF
NFACTOR
ETA0
VDSCALE
CDSCD
U0
Page
Parameter Extraction II
Adjust Ron using
NS0ACCS
NS0ACCD
MOS-AK Workshop Shanghai 2016 9
Id-Vgs, gm-Vgs and Id-Vds, gds-Vds
Page
Parameter Extraction III
Fit Saturation Current by adjusting
VSATACCS
VSAT should remain more or less the same
since it is a material dependent parameter
and should not vary much for different GaN
Technologies
MOS-AK Workshop Shanghai 2016 10
Id-Vgs, gm-Vgs and Id-Vds, gds-Vds
Page
Parameter Extraction IV
Fine tune Contact Resistance parameters
RDC
RSC
To further fit the Ron
MOS-AK Workshop Shanghai 2016 11
Id-Vgs, gm-Vgs and Id-Vds, gds-Vds
Page
Self Heating and Temperature Related Parameters
MOS-AK Workshop Shanghai 2016 12
RTH0
KT1
AT
ATS
KRSC
KRDC
UTE
Page
Field Plate Capacitance Model
MOS-AK Workshop Shanghai 2016 13
Terminal Capacitances
Ciss = Cgs + Cgd
Crss = Cgd
Coss = Cds + Cgd
FP Modeled as an intrinsic HEMT
Each HEMT governed by ๐ Calc.
Page
Field Plate MOD Parameter Extraction I
MOS-AK Workshop Shanghai 2016 14
Ciss โ Vgs
-150V < Vgs < 0V
Vds = 0
Crss, Ciss, Coss versus Vds
0V < Vds < 300V
Vgs = -15V
GFPMOD = SFPMOD = 1
Ciss โ VgsCiss โ Vds
Crss โ VdsCoss โ Vds
CFG
CFD
CFG
Page
Field Plate MOD Parameter Extraction II
MOS-AK Workshop Shanghai 2016 15
VOFFGFP โ sets the rise of the hump
ADOS โ Smoothens the hump
CFGD
CFGD0
VOFFGFP
CFGD
CFGD0
Gate FP - Drain
Fringing capacitance
Page
Field Plate MOD Parameter Extraction III
MOS-AK Workshop Shanghai 2016 16
Optimize the following
AJ
CJ0
MZ
VBI
CFD
AJ, CJ0,
MZ, VBI
Page
ASM HEMT - Small Signal Representation
MOS-AK Workshop Shanghai 2016 17
ASM-HEMT
๐๐๐ถ๐๐
๐ถ๐๐
๐ถ๐๐
๐ ๐๐ ๐
๐
๐๐๐
๐11 =๐๐ ๐ถ๐๐ + ๐ถ๐๐
1 + ๐2 ๐ถ๐๐ + ๐ถ๐๐2๐ ๐2+
๐2 ๐ถ๐๐ + ๐ถ๐๐2๐ ๐
1 + ๐2 ๐ถ๐๐ + ๐ถ๐๐2๐ ๐2
๐12 = โ๐๐๐ถ๐๐ โ ๐2๐ถ๐๐(๐ถ๐๐ + ๐ถ๐๐)๐ ๐
๐21 = ๐๐ โ ๐2๐ถ๐๐ ๐ถ๐๐ + ๐ถ๐๐ ๐ ๐ โ ๐๐ ๐ถ๐๐ + ๐๐ ๐ถ๐๐ + ๐ถ๐๐ ๐ ๐
๐22 = ๐๐๐ + ๐๐ ๐ถ๐๐ + ๐ถ๐๐(1 + ๐๐๐ ๐)
Page
De-embedded Y-Parameters (0.5-10 GHz)
MOS-AK Workshop Shanghai 2016 18
๐๐๐๐ ๐๐๐
๐๐
๐๐๐๐ ๐๐๐
๐๐ ๐
๐๐๐๐ ๐๐๐
๐ช๐๐+ ๐ช๐๐
โ๐๐๐๐ ๐๐๐
๐ช๐๐
๐๐๐๐ ๐๐๐
๐ช๐ ๐
Page
Broadband S-Parameters (0.5-50 GHz)
MOS-AK Workshop Shanghai 2016 19
๐บ๐๐ ๐บ๐๐
๐บ๐๐ ๐บ๐๐
๐๐๐
๐๐๐
๐๐๐
๐๐๐
๐๐๐๐ฅ ๐๐ฆ๐๐
Page
Load-Pull and Harmonic Balance Simulations
MOS-AK Workshop Shanghai 2016 20
๐ท๐๐๐ ๐ฎ๐๐๐
๐ท๐จ๐ฌ ๐ฐ๐ ๐
๐ช๐๐๐๐๐๐๐ ๐ท๐๐๐
๐ช๐๐๐๐๐๐๐ ๐ท๐จ๐ฌ
Measured Model
Page
โ As one of the candidates for CMC GaN HEMT, ASM-HEMT is a physical model base
on surface potential analytical calculation
โ Model extraction procedure
โข DC parameter extraction โ Focused on key parameters
โข Model field plate as a transistor and perform capacitance parameter extraction
โข RF modeling
- Broadband S-Parameters and Y-Parameters
- Large signal load pull and harmonic balance power sweeps
โ The model is developed by using Keysightโs IC-CAP and ADS software. Good fitting is
achieved with industry measured data.
MOS-AK Workshop Shanghai 2016 21
Summary
Page
โ S. Khandelwal, Y. S. Chauhan, and T. A. Fjeldly, โAnalytical Modeling of Surface-Potential and
Intrinsic Charges in AlGaN/GaN HEMT Devices,โ IEEE Trans. Electron Devices, vol. 59, no. 10,
pp. 2856-2860, Oct. 2012.
โ S. Khandelwal, et al., โRobust Surface-Potential-Based Compact Model for GaN HEMT IC
Design,โ IEEE Trans. Electron Devices, vol. 60, no. 10, pp. 3216-3222, Oct. 2013.
โ S. A. Ahsan, et al., โCapacitance Modeling in Dual Field-Plate Power GaN HEMT for Accurate
Switching Behavior,โ IEEE Trans. Electron Devices, vol. 63, no. 2, pp. 565-572, Feb. 2016.
โ S. Khandelwal, et al., โSurface-Potential-Based RF Large Signal Model for Gallium Nitride
HEMTs,โ Proc. IEEE Compound Semiconductor Integrated Circuit Symp. (CSICS), pp. 1-4, 2015.
โ S. Ghosh et al., โSurface-potential-based compact modeling of gate current in AlGaN/GaN
HEMTsโ, IEEE TED, vol. 62, no. 2, 2015
MOS-AK Workshop Shanghai 2016 22
References