Comparison of AlGaN/GaN insulated gate heterostructure field-effect transistors with ultrathin Al2O3/Si3N 4 bilayer and Si3N4 single layer

Chengxin Wang, Narihiko Maeda, Masanobu Hiroki, Takehiko Tawara, Toshiki Makimoto, Takashi Kobayashi, Takotomo Enoki

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13 Citations (Scopus)


Device performances have been compared between two types of AlGaN/GaN metal-insulator-semiconductor heterostructure field effect transistors (MIS-HFETs) with Al2O3/Si3N4 bilayers and a Si3N4 single layer. Al2O 3/Si3N4 bilayer-based MIS-HFETs have much lower gate current leakage than Si3N4-based MIS devices by more than 3 orders of magnitude under reverse gate biases. An ultralow gate leakage of 1 × 10-11 A/mm at -15V has been achieved in the Al 2O3/Si3N4 bilayer-based MIS devices though higher maximum drain-source current has been obtained in the Si 3N4-based MIS devices. A maximum transconductance of more than 180 mS/mm with ultra-low gate leakage has been achieved in the ultrathin Al2O3/ Si3N4 bilayer-based MIS-HFET device with a gate length of 1.5 μm, which is much higher than that of less than 130 mS/mm in the Si3N4-based MIS devices. The reduction in the transconductance of Al2O3/Si 3N4 bilayer-based devices was much smaller than that in the Si3N4-based MIS devices due to the employment of ultrathin bilayers with a large dielectric constant.This work demonstrates that an Al2O3/Si3N4 bilayer insulator is a superior candidate for nitride-based MIS-HFET devices.

Original languageEnglish
Pages (from-to)2735-2738
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number4 B
Publication statusPublished - 2005 Apr
Externally publishedYes


  • Alo /sin dielectric layer
  • Field-effect transistor
  • Metal-insulator-semiconductor

ASJC Scopus subject areas

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


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