Effect of epitaxial layer crystal quality on DC and RF characteristics of AlGaN/GaN short-gate high-electron-mobility transistors on sapphire substrates

Kenji Shiojima, Takashi Makimura, Tetsuya Suemitsu, Naoteru Shigekawa

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The DC and RF characteristics of short-gate high-electron-mobility transistors (HEMTs) formed on four AlGaN/GaN wafers grown on sapphire substrates with different crystal quality have been investigated. Atomic force microscopy observation revealed many pits and trenches on the AlGaN surface, and the morphology of each sample was distinct. There were also differences in electron mobility and sheet carrier concentration. However, the gate length dependences of the measured transconductance and cut-off frequency were virtually the same. For a more detailed investigation, we subtracted the source resistance and AlGaN thickness contributions from measured DC and performed a delay time analysis for the RF characteristics. The results indicate that the intrinsic performance of HEMTs was independent of the surface morphology and that effective electron velocity ranged from 1.4 to 1.8 × 107 cm/s.

Original languageEnglish
Pages (from-to)8435-8440
Number of pages6
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume44
Issue number12
DOIs
Publication statusPublished - 2005 Dec 8
Externally publishedYes

Keywords

  • AlGaN/GaN heterostructure
  • Electron velocity
  • HEMT
  • Intrinsic characteristic
  • Surface morphology

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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