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, Ji Hyun Kim

Research output: Contribution to journalArticle

2 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/cm 2 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: Microelectronics and Nanometer Structures
Volume30
Issue number1
DOIs
Publication statusPublished - 2012 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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