DC characteristics in high-quality AlGaN/AlN/GaN high-electron-mobility transistors grown on AIN/sapphire templates

Makoto Miyoshi, Atsushi Imanishi, Takashi Egawa, Hiroyasu Ishikawa, Kei Ichiro Asai, Tomohiko Shibata, Mitsuhiro Tanaka, Osamu Oda

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High-crystal-quality Al0.26Ga0.74N/AlN/GaN structures with a very high mobility, such as over 2100cm2/(V s) with a two-dimensional-electron gas (2DEG) density of approximately 1 × 10 13/cm2, were grown on epitaxial AIN/sapphire templates by metalorganic vapor phase epitaxy and adopted for the fabrication of high-electron-mobility transistors (HEMTs). The fabricated devices showed good DC characteristics compared with those in conventional AlGaN/GaN HEMTs and in devices grown on sapphire substrates. Also, it was confirmed that further improvements in DC characteristics are achieved by applying recessed ohmic contacts to AlGaN/AlN/GaN HEMTs. A high extrinsic transconductance of approximately 220mS/mm and a high drain current density of over 1 A/mm with a threshold voltage of -4.08 V were obtained for 1,5-μm-gate-length recessed ohmic AlGaN/AlN/GaN HEMTs on AIN/sapphire templates. In addition, it was found that the gate leakage current of HEMTs can be suppressed by using epitaxial AIN/sapphire templates as substrates.

Original languageEnglish
Pages (from-to)6490-6494
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number9 A
Publication statusPublished - 2005 Sep 8



  • AIN/sapphire template
  • HEMT
  • Recessed ohmic

ASJC Scopus subject areas

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

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