Microstructure of Ti/Al/Ni/Au ohmic contacts for N-polar GaN/AlGaN high electron mobility transistor devices

Lin Zhou, Michael R. Johnson, David Smith, David J. Meyer, David F. Storm, Douglas Scott Katzer, Brian P. Downey

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The microstructure of Ti/Al/Ni/Au ohmic contacts on N-polar GaN/AlGaN high electron mobility transistor heterostructures annealed from 800 °C to 900 °C has been studied using transmission electron microscopy and associated analytical techniques. Two ohmic metal stacks with different Ti/Al/Ni/Au layer thicknesses (20/200/40/50 nm and 20/100/10/50 nm) have been examined. Samples with low ohmic contact resistance after annealing were found to have two common characteristics: (1) the top GaN channel layer had completely reacted with Ti metal to form a polycrystalline TiN layer and (2) a ∼5 nm-thick Au-rich layer was present near the TiN/AlGaN interface. Possible conduction mechanisms related to the presence of Au in low ohmic contact resistance samples are discussed.

Original languageEnglish (US)
Article number011201
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume32
Issue number1
DOIs
StatePublished - Jan 1 2014

Fingerprint

Ohmic contacts
High electron mobility transistors
high electron mobility transistors
electric contacts
Contact resistance
microstructure
Microstructure
contact resistance
Metals
Heterojunctions
metals
Annealing
Transmission electron microscopy
conduction
transmission electron microscopy
annealing
aluminum gallium nitride

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Process Chemistry and Technology
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Materials Chemistry
  • Instrumentation

Cite this

Microstructure of Ti/Al/Ni/Au ohmic contacts for N-polar GaN/AlGaN high electron mobility transistor devices. / Zhou, Lin; Johnson, Michael R.; Smith, David; Meyer, David J.; Storm, David F.; Scott Katzer, Douglas; Downey, Brian P.

In: Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics, Vol. 32, No. 1, 011201, 01.01.2014.

Research output: Contribution to journalArticle

Zhou, Lin ; Johnson, Michael R. ; Smith, David ; Meyer, David J. ; Storm, David F. ; Scott Katzer, Douglas ; Downey, Brian P. / Microstructure of Ti/Al/Ni/Au ohmic contacts for N-polar GaN/AlGaN high electron mobility transistor devices. In: Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics. 2014 ; Vol. 32, No. 1.
@article{a4dace99aaa34261b38c220923f903c9,
title = "Microstructure of Ti/Al/Ni/Au ohmic contacts for N-polar GaN/AlGaN high electron mobility transistor devices",
abstract = "The microstructure of Ti/Al/Ni/Au ohmic contacts on N-polar GaN/AlGaN high electron mobility transistor heterostructures annealed from 800 °C to 900 °C has been studied using transmission electron microscopy and associated analytical techniques. Two ohmic metal stacks with different Ti/Al/Ni/Au layer thicknesses (20/200/40/50 nm and 20/100/10/50 nm) have been examined. Samples with low ohmic contact resistance after annealing were found to have two common characteristics: (1) the top GaN channel layer had completely reacted with Ti metal to form a polycrystalline TiN layer and (2) a ∼5 nm-thick Au-rich layer was present near the TiN/AlGaN interface. Possible conduction mechanisms related to the presence of Au in low ohmic contact resistance samples are discussed.",
author = "Lin Zhou and Johnson, {Michael R.} and David Smith and Meyer, {David J.} and Storm, {David F.} and {Scott Katzer}, Douglas and Downey, {Brian P.}",
year = "2014",
month = "1",
day = "1",
doi = "10.1116/1.4829878",
language = "English (US)",
volume = "32",
journal = "Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics",
issn = "2166-2746",
publisher = "AVS Science and Technology Society",
number = "1",

}

TY - JOUR

T1 - Microstructure of Ti/Al/Ni/Au ohmic contacts for N-polar GaN/AlGaN high electron mobility transistor devices

AU - Zhou, Lin

AU - Johnson, Michael R.

AU - Smith, David

AU - Meyer, David J.

AU - Storm, David F.

AU - Scott Katzer, Douglas

AU - Downey, Brian P.

PY - 2014/1/1

Y1 - 2014/1/1

N2 - The microstructure of Ti/Al/Ni/Au ohmic contacts on N-polar GaN/AlGaN high electron mobility transistor heterostructures annealed from 800 °C to 900 °C has been studied using transmission electron microscopy and associated analytical techniques. Two ohmic metal stacks with different Ti/Al/Ni/Au layer thicknesses (20/200/40/50 nm and 20/100/10/50 nm) have been examined. Samples with low ohmic contact resistance after annealing were found to have two common characteristics: (1) the top GaN channel layer had completely reacted with Ti metal to form a polycrystalline TiN layer and (2) a ∼5 nm-thick Au-rich layer was present near the TiN/AlGaN interface. Possible conduction mechanisms related to the presence of Au in low ohmic contact resistance samples are discussed.

AB - The microstructure of Ti/Al/Ni/Au ohmic contacts on N-polar GaN/AlGaN high electron mobility transistor heterostructures annealed from 800 °C to 900 °C has been studied using transmission electron microscopy and associated analytical techniques. Two ohmic metal stacks with different Ti/Al/Ni/Au layer thicknesses (20/200/40/50 nm and 20/100/10/50 nm) have been examined. Samples with low ohmic contact resistance after annealing were found to have two common characteristics: (1) the top GaN channel layer had completely reacted with Ti metal to form a polycrystalline TiN layer and (2) a ∼5 nm-thick Au-rich layer was present near the TiN/AlGaN interface. Possible conduction mechanisms related to the presence of Au in low ohmic contact resistance samples are discussed.

UR - http://www.scopus.com/inward/record.url?scp=84929598426&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84929598426&partnerID=8YFLogxK

U2 - 10.1116/1.4829878

DO - 10.1116/1.4829878

M3 - Article

AN - SCOPUS:84929598426

VL - 32

JO - Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics

JF - Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics

SN - 2166-2746

IS - 1

M1 - 011201

ER -