Simulation and experimental study of ArF 193 nm laser lift-off AlGaN/GaN high electron mobility transistors

T. S. Kang, X. T. Wang, C. F. Lo, F. Ren, S. J. Pearton, O. Laboutin, Yu Cao, J. W. Johnson, Jihyun Kim

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A finite element simulation was used to estimate the temperature distributions within AlGaN/GaN high electron mobility transistors (HEMTs) during the laser lift-off process. The time-dependent simulation showed that a thin layer of GaN at the GaN/sapphire interface was heated up to around 1600 K in less than 25 ns by a pulsed laser exposure with a duration of 25 ns and a fluence of 800 mJ/cm2 to decompose this GaN layer into Ga and nitrogen. Experimentally, there was a threshold fluence around 550 mJ/cm 2, corresponding to 1300 K at the GaN/sapphire interface, for partially lifting off the HEMT structure from the sapphire. The simulated temperature at the GaN/sapphire interface with a fluence of 420 mJ/cm 2 never reached above 1000 K, however, the HEMT structure was lifted-off by multiple laser exposures at this fluence. Therefore, instead of thermally induced decomposition, the lift-off mechanism could also be through the Ga-N bond breaking during the multiple lower-fluence high-energy 193 nm laser exposures.

Original languageEnglish
Article number011203
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume30
Issue number1
DOIs
Publication statusPublished - 2012 Jan
Externally publishedYes

ASJC Scopus subject areas

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

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