Transmission electron microscopy characterization of electrically stressed AlGaN/GaN high electron mobility transistor devices

Michael R. Johnson, David A. Cullen, Lu Liu, Tsung Sheng Kang, Fan Ren, Chih Yang Chang, Stephen J. Pearton, Soohwan Jang, Wayne J. Johnson, David Smith

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A set of AlGaN/GaN high electron mobility transistor devices has been investigated using step-stress testing, and representative samples of undegraded, source-side-degraded, and drain-side-degraded devices were examined using electron microscopy and microanalysis. An unstressed reference sample was also examined. All tested devices and their corresponding transmission electron microscopy samples originated from the same wafer and thus received nominally identical processing. Step-stressing was performed on each device and the corresponding current-voltage characteristics were generated. Degradation in electrical performance, specifically greatly increased gate leakage current, was shown to be correlated with the presence of crystal defects near the gate edges. However, the drain-side-degraded device showed a surface pit on the source side, and another region of the same device showed no evidence of damage. Moreover, significant metal diffusion into the barrier layer from the gate contacts was also observed, as well as thin amorphous oxide layers below the gate metal contacts, even in the unstressed sample. Overall, these observations emphasize that gate-edge defects provide only a partial explanation for device failure.

Original languageEnglish (US)
Article number062204
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume30
Issue number6
DOIs
StatePublished - Nov 2012

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High electron mobility transistors
high electron mobility transistors
Metals
Transmission electron microscopy
transmission electron microscopy
Crystal defects
Microanalysis
Current voltage characteristics
Leakage currents
Oxides
Electron microscopy
Degradation
Defects
Testing
Processing
barrier layers
aluminum gallium nitride
microanalysis
crystal defects
metals

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Transmission electron microscopy characterization of electrically stressed AlGaN/GaN high electron mobility transistor devices. / Johnson, Michael R.; Cullen, David A.; Liu, Lu; Sheng Kang, Tsung; Ren, Fan; Chang, Chih Yang; Pearton, Stephen J.; Jang, Soohwan; Johnson, Wayne J.; Smith, David.

In: Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics, Vol. 30, No. 6, 062204, 11.2012.

Research output: Contribution to journalArticle

Johnson, Michael R. ; Cullen, David A. ; Liu, Lu ; Sheng Kang, Tsung ; Ren, Fan ; Chang, Chih Yang ; Pearton, Stephen J. ; Jang, Soohwan ; Johnson, Wayne J. ; Smith, David. / Transmission electron microscopy characterization of electrically stressed AlGaN/GaN high electron mobility transistor devices. In: Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics. 2012 ; Vol. 30, No. 6.
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