Modeling of 70nm GaAs mHEMT Process for MMIC Amplifier … · 2018-08-02 · Modeling of 70nm GaAs...
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Modeling of 70nm GaAs mHEMT Process for MMIC Amplifier Design up to 220GHz
YangTang*, HuabingZhu, HaikunYue, BoshenChen, BinbinCheng, XianjinDeng
Microsystem and Terahertz Research Center, Chengdu, China
*Email: [email protected], [email protected]
Yinhe596 S&T Campus
Location: Shuangliu District, Chengdu
Strategic new tech research centers: info tech, advanced manufacturing, new
materials,…
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Microsystem and Terahertz Research Center(MTRC)4 research labs
latest EDA platform for design, state of the art THz characterization & measurement equipment
in-house fabrication facility with 3000+m^2 cleanroom for III-V, MEMS & system integration
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MT03: THz Application Technology Research Laboratory
Yinhe596MTRC
MT03
Active in research fieldsTHz communications, radar,
imaging systemsTHz components, THz ICs,
THz microsystems integration
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Outline
Background & Motivation
Test chip & Characterization
Modeling Methodologies & Results
Summary
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Modeling of 70nm GaAs mHEMT Process for MMIC Amplifier Design up to 220GHz
Background & MotivationTHz gap
huge bandwidth, high data rate, applications in high speed communication
III-V transistor speedInP HEMTs with fmax >1THz, amplifier even work at
1THz by NGCFew COTS modules available
Foundry process70nm GaAs mHEMTfmax>400GHzamplifiers beyond 100GHz
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1THz TMIC Amplifier by NGC
Background & MotivationPDK model
only verified up to 50GHzunknown uncertainty for THzhigh risk and costly redesign
Evaluation of devices is necessaryfor beyond 100GHz design
small components value sensitive to variation and modeling error
passives and transistors passives: EM helps but need calibration and verification transistor modeling as an integral part of the amplifier
design flow
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Test Chip
Test structures for evaluation and modelingcompact design
1x3mm^2
CPW environmentG-G 40um, signal trace 20um for 50Ohm TXL
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Typical Test Structures
mHEMTs
Resistors
Capacitors
Inductors
TXLs…
GSG pads 75-100um
200um separation
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Devices CharacterizationOn-wafer banded s-parameters
measurements
100um GSG probes
10MHz~67GHz(x3)
VNA frequency extenders 75GHz~110GHz(x2) 10MHz~110GHzD:110GHz~170GHG:140GHz~220GHz
6 setups measurement systems in 5 labs
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Devices Characterization
Measured on probe station with:dies glued on
copper carrier by silver epoxyto mimic the
targeted working environment
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Devices Characterization
Calibration and De-embedding[1]1st tier calibration using LRRM with ISSOPEN/SHORT/PAD dummies for OS, POS de-
embeddingon-wafer multiline TRL calibration
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[1]P. Manuel, S. Fregonese, A. Curutchet, et al, EuMC, p.167(2015).
Comparison of calibration and de-embedding effect on transconductance
Devices Characterization
Calibration and De-embeddingPOS up to 67GHzmTRL is used in other bands
generally effective
Some problems discontinuitiesunreal artifacts Incorrect signoriginate from data
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Adopted calibration and de-embedding applied on transconductance for reference
Measurement Non-idealities
Raw S11 of PAD dummyespecially obvious
for magnitude of s-parameters
Ref[2]Parasitic scattering
and coupling
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[2]M. Seelmann-Eggebert, M. Ohlrogge, R Webber, et al, MTT, 63(7), p.2335(2015).
Parasitic Scattering & Coupling E-Field distribution for a CPW transmission
line100GHz
200GHz
300GHz
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Parasitic Scattering & Couplingfull test chip EM
simulation
@200GHz
unwanted coupling to adjacent test structures
results in degraded data
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Parasitic Scattering & CouplingSome characteristics and test structures are
less sensitive Effective inductance, capacitance, phase of
transmission termslong transmission line
Effective L, Phase
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Modeling MethodologiesConsidering the data degradation up to
220GHzFollowing strategies are used:Systematic calibration of EM simulation
For parasitics extraction and measurement verification
Feeding network modeling replace de-embedding and on-wafer calibration
Recursive Modeling[3] of mHEMTpreviously extracted equivalent circuit model(ECM)
used recursively in later extractions
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[3]Babak Heydari, Dissertation, UCB/EECS (2008).
Modeling MethodologiesModeling in flowchart
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EM Calibration
Systematic EM calibration[4]Simplified process cross-section profilebased on measurement data of SHORT, LINEs
and Caps structuresHFSS and Momentum
Materials parameters thickness
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[4]K. Takano, K. Katayama, S. Mizukusa, et al, ICMTS, p. 230 (2015).
EM Calibration Results
100fF Cmim
Si3N4, SiO2 dielectric from 2 Capsverified up to 170GHz
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EM Calibration Results
Transmission linesConductivity from effective resistanceGaAs substrate dielectric from LINEsHFSS and ADS similar results
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EM Calibration Results
200Ohm ResistorThin film metal resistorverified up to 110GHz
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Feeding network modeling
2x20um mHMET with feeding parasiticsReference planes
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Feeding network modeling
Feeding network modelingbased on PAD, SHORT and OPEN dummy
structures
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Feeding network modeling
Extraction recursivelyEach extracted ECM is used as part of
the subsequent ECMPADSHORTOPEN
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Feeding Networks Results
PAD dummyEM vs. data Cpg, Cpd
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Feeding Networks Results
SHORT dummyEM vs. dataRg,Lg
Rg1,Lg1
Rd,Ld
Rd1,Ld1
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Feeding Networks Results
OPEN DummyEM vs. data Cpg1,Cpg2
Cdg,Cdg1
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Recursive Modeling
mHEMT modelPi-network embedded in the feeding ECMused raw measurement data as targets
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Extrinsic Elements Extraction
Cold-FET for terminal parasiticssource parasitics and res at G,D ignored
Lge, Lde
Recursive methods, fitting to raw data(>110GHz)
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Intrinsic ECM Extraction
Intrinsic elementsstarting value: extracted from low frequency de-
embedded data(<110GHz)then fitting together with feeding network ECM
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Meas vs. Sim ResultsmHEMT 2x20um Vg=0V Vd=1V(close to peak
transconductance)
gm, Cm
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Meas vs. Sim ResultsmHEMT 2x20um Vg=0V Vd=1V Cgs, re(Y11+Y12)
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Meas vs. Sim ResultsmHEMT 2x20um Vg=0V Vd=1VCds, 1/Rds
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Meas vs. Sim ResultsmHEMT 2x20um Vg=0V Vd=1VCgd, re(1/Y12)
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Meas vs. Sim Results
mHEMT 2x20um Vg=0V Vd=1VMAGS-parameters Smith plots
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Model Application
3-stage CS amplifierT-junction matchingGain>20dB@140GHz
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SummaryTest chip & CharacterizationCompact, CPW styleOn-wafer banded measurements with non-
idealities
Modeling Methodologies & ResultsEM calibration for parasitics extraction and
verification of measurementFeeding network modeling instead of de-
embedding and calibrationRecursive modeling of mHEMT up to 220GHz,
to be used in amplifier design
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Ref & AcknowledgementReferences
[1]P. Manuel, S. Fregonese, A. Curutchet, et al, EuMC, p.167(2015).
[2]M. Seelmann-Eggebert, M. Ohlrogge, R Webber, et al, MTT, 63(7), p.2335(2015).
[3]Babak Heydari, Dissertation, UCB/EECS (2008).
[4]K. Takano, K. Katayama, S. Mizukusa, et al, ICMTS, p. 230 (2015).
Acknowledgement This work was supported by Challenge Program under grant no. TZ2018003.
The authors would like to thank Prof. Yan Wang, Wenyuan Zhang of Tsinghua University, Miao Li, Haibin Zhao of Platform Design Automation Inc, Prof. Jun Liu of Zhangzhou Dianzi University, Zhifu Hu, Meilin He of CETC13 for their help and technical discussions.
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Thanks for your attention.
Modeling of 70nm GaAs mHEMT Process for MMIC Amplifier Design up to 220GHz