Improving Current ON/OFF Ratio and Subthreshold Swing of Schottky- Gate AlGaN/GaN HEMTs by Postmetallization Annealing

Hsuan Ping Lee, Can Bayram

Research output: Contribution to journalArticlepeer-review


Al2O3-passivated Schottky-gate AlGaN/GaN high electron mobility transistors (HEMTs) with improved subthreshold swing (SS) and drain current ON/OFF ratio by postmetallization annealing (PMA) at 500 °C in N2 ambient are reported. With the PMA, the gate leakage current in the reverse biased region and the OFF-state drain current are reduced by more than three orders of magnitude, leading to a low SS of 84.75 mV/dec and a high drain current ON/ OFF ratio of 2.1\times 10^{7}. Through temperature-dependent current-voltage measurements on dual-Schottky-gate structures and capacitance-voltage measurements on Al2O3/AlGaN/GaN metal-insulator-semiconductor (MIS) HEMT capacitors, it is identified that the PMA greatly suppresses both the Al2O3/AlGaN interface leakage current and the reverse gate leakage current by eliminating Al2O3/AlGaN interface trap states with 0.34 eV trap state energy and changing the dominant mechanism of reverse gate leakage conduction from trap-assisted tunneling to Fowler-Nordheim tunneling, respectively. Overall, this work reports on the effectiveness of PMA in improving the performance of Schottky-gate AlGaN/GaN HEMTs and the underlying improving mechanisms.

Original languageEnglish (US)
Article number9094302
Pages (from-to)2760-2764
Number of pages5
JournalIEEE Transactions on Electron Devices
Issue number7
StatePublished - Jul 2020


  • AlGaN
  • GaN
  • drain current ON/OFF ratio
  • high electron mobility transistor (HEMT)
  • leakage
  • postmetallization annealing (PMA)
  • subthreshold swing (SS)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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