Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates

Hareesh Chandrasekar; Michael J. Uren; Abdalla Eblabla; Hassan Hirshy; Michael A. Casbon; Paul J. Tasker; Khaled Elgaid; Martin Kuball

doi:10.1109/LED.2018.2864562

Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates

Hareesh Chandrasekar, Michael J. Uren, Abdalla Eblabla, Hassan Hirshy, Michael A. Casbon, Paul J. Tasker, Khaled Elgaid, Martin Kuball

School of Physics

Research output: Contribution to journal › Article (Academic Journal) › peer-review

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Abstract

We demonstrate that the highly-resistive Si substrate in GaN-on-Si RF HEMTs does not act as an insulator, but instead behaves as a conductive ground plane for static operation and can cause significant back-gate induced current collapse. Substrate ramp characterization of the buffer shows good agreement with device simulations and indicates that the current collapse is caused by charge-redistribution within the GaN layer. Potential solutions which alter charge storage and leakage in the epitaxy to counter this effect are then presented.

Original language	English
Pages (from-to)	1556-1559
Number of pages	4
Journal	IEEE Electron Device Letters
Volume	39
Issue number	10
Early online date	10 Aug 2018
DOIs	https://doi.org/10.1109/LED.2018.2864562
Publication status	Published - Oct 2018

Research Groups and Themes

CDTR

Keywords

Buffer storage
current collapse
Epitaxial growth
Gallium nitride
GaN buffers
HEMTs
high resistivity silicon
Radio frequency
RF transistors
Silicon
substrate ramps
Substrates

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10.1109/LED.2018.2864562

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@article{334d20b66f7c4ef6b80ce9498aa387e6,

title = "Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates",

abstract = "We demonstrate that the highly-resistive Si substrate in GaN-on-Si RF HEMTs does not act as an insulator, but instead behaves as a conductive ground plane for static operation and can cause significant back-gate induced current collapse. Substrate ramp characterization of the buffer shows good agreement with device simulations and indicates that the current collapse is caused by charge-redistribution within the GaN layer. Potential solutions which alter charge storage and leakage in the epitaxy to counter this effect are then presented.",

keywords = "Buffer storage, current collapse, Epitaxial growth, Gallium nitride, GaN buffers, HEMTs, high resistivity silicon, Radio frequency, RF transistors, Silicon, substrate ramps, Substrates",

author = "Hareesh Chandrasekar and Uren, {Michael J.} and Abdalla Eblabla and Hassan Hirshy and Casbon, {Michael A.} and Tasker, {Paul J.} and Khaled Elgaid and Martin Kuball",

year = "2018",

month = oct,

doi = "10.1109/LED.2018.2864562",

language = "English",

volume = "39",

pages = "1556--1559",

journal = "IEEE Electron Device Letters",

issn = "0741-3106",

publisher = "Institute of Electrical and Electronics Engineers (IEEE)",

number = "10",

}

TY - JOUR

T1 - Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates

AU - Chandrasekar, Hareesh

AU - Uren, Michael J.

AU - Eblabla, Abdalla

AU - Hirshy, Hassan

AU - Casbon, Michael A.

AU - Tasker, Paul J.

AU - Elgaid, Khaled

AU - Kuball, Martin

PY - 2018/10

Y1 - 2018/10

N2 - We demonstrate that the highly-resistive Si substrate in GaN-on-Si RF HEMTs does not act as an insulator, but instead behaves as a conductive ground plane for static operation and can cause significant back-gate induced current collapse. Substrate ramp characterization of the buffer shows good agreement with device simulations and indicates that the current collapse is caused by charge-redistribution within the GaN layer. Potential solutions which alter charge storage and leakage in the epitaxy to counter this effect are then presented.

AB - We demonstrate that the highly-resistive Si substrate in GaN-on-Si RF HEMTs does not act as an insulator, but instead behaves as a conductive ground plane for static operation and can cause significant back-gate induced current collapse. Substrate ramp characterization of the buffer shows good agreement with device simulations and indicates that the current collapse is caused by charge-redistribution within the GaN layer. Potential solutions which alter charge storage and leakage in the epitaxy to counter this effect are then presented.

KW - Buffer storage

KW - current collapse

KW - Epitaxial growth

KW - Gallium nitride

KW - GaN buffers

KW - HEMTs

KW - high resistivity silicon

KW - Radio frequency

KW - RF transistors

KW - Silicon

KW - substrate ramps

KW - Substrates

UR - http://www.scopus.com/inward/record.url?scp=85052576349&partnerID=8YFLogxK

U2 - 10.1109/LED.2018.2864562

DO - 10.1109/LED.2018.2864562

M3 - Article (Academic Journal)

AN - SCOPUS:85052576349

SN - 0741-3106

VL - 39

SP - 1556

EP - 1559

JO - IEEE Electron Device Letters

JF - IEEE Electron Device Letters

IS - 10

ER -

Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates

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High Performance Buffers for RF GaN Electronics

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Buffer Induced Current-Collapse in GaN HEMTs on Highly Resistive Si Substrates

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High Performance Buffers for RF GaN Electronics

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