193 nm excimer laser lift-off for AlGaN/GaN high electron mobility transistors

Xiaotie Wang, Chien Fong Lo, Lu Liu, Camilo V. Cuervo, Ren Fan, Stephen J. Pearton, Brent Gila, Michael R. Johnson, Lin Zhou, David Smith, Jihyun Kim, Oleg Laboutin, Yu Cao, Jerry W. Johnson

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


AlGaN/GaN HEMTs grown on both-side-polished sapphire substrates were successfully lifted-off with a 193-nm UV excimer laser system. The photon energy of the 193 nm laser is larger than the band gap of AlN and thus it can be used to lift-off AlGaN HEMT structures with AlN or AlGaN interfacial layers grown on sapphire substrates prior to growth of the GaN buffer layers. The lifted-off HEMT chip was warped and showed 25-42 reduction of the saturation drain current. There was no degradation observed either in the forward or reverse gate current-voltage (I-V) characteristics or on the drain punch-through voltage. Based on comparisons of cross-sectional electron micrographs, no additional dislocations were created in the HEMT structures after the laser lift-off process. Reduction in saturation drain current was attributed to relaxation of the lifted-off HEMT structures. Newtons rings and Raman spectrum E2 peak shifts were used to estimate the strain relaxation of the laser lifted-off samples.

Original languageEnglish (US)
Article number051209
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Issue number5
StatePublished - Sep 2012

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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