Investigations of novel Γ-gate MOS-HEMTs by ozone water oxidation and shifted exposure techniques

Ching Sung Lee, Bo Yi Chou, Sheng Han Yang, Wei Chou Hsu, Chang Luen Wu, Wen Luh Yang, Don Gey Liu, Ming Yuan Lin

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11 Citations (Scopus)


A novel Γ-gate Al0.24Ga0.76As/In 0.15Ga0.85As metal-oxide-semiconductor (MOS) high-electron-mobility transistor (MOS-HEMT) by using methods of ozone water oxidation and shifted exposure has been comprehensively investigated. Effective gate-length reduction, improved gate insulation, and formations of a field plate and a full surface passivation within the drain-source region are simultaneously achieved. The present Γ-gate MOS-HEMT has demonstrated superior device performances, including improvements of 523% (12.8%) in two-terminal gate-drain breakdown, 137% (36.1%) in on-state drain-source breakdown, 16.1% (11.8%) in maximum extrinsic transconductance (g m, max), 34.5% (9.7%) in intrinsic voltage gain (AV), 27.8% (16.2%) in power-added efficiency, 34.5% (19.8%) in minimum noise figure (NFmin) , and 28%/39.3% (11.4%/21.6%) in unity-gain cutoff frequency/maximum oscillation frequency (fT/fmax), as compared to a conventional Schottky-gate (MOS-gate) device fabricated upon the same epitaxial structure by using an identical optical mask set. Investigations of optimum extracted parasitics, small-signal device parameters, and high-temperature device characteristics at 300 K-450 K are also made in this work.

Original languageEnglish
Article number5958594
Pages (from-to)2981-2989
Number of pages9
JournalIEEE Transactions on Electron Devices
Issue number9
Publication statusPublished - 2011 Sep

All Science Journal Classification (ASJC) codes

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


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