Investigations of AlGaN/GaN HFETs utilizing post-metallization etching by nitric acid treatment

Bo Yi Chou, Wei-Chou Hsu, Ching Sung Lee, Han Yin Liu, Chih-Ming Tsai, Chiu Sheng Ho

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5 Citations (Scopus)

Abstract

This work investigates AlGaN/GaN heterostructure field-effect transistors (HFETs) processed by using a simple post-metallization etching (PME) treatment. Decreased gate length (LG) can be achieved by using nitric acid (HNO3) PME treatment owing to the high etching selectivity of HNO3 of Ni against the Au and GaN layer. Influences on LG, etched gate profiles and device characteristics with respect to different PME processing parameters by HNO3 treatment are systematically investigated. Optimum device performance is obtained as LG was reduced to 0.5 μm by using a 1 μm long gate mask by immersing the device into a 45% diluted HNO3 solution for 35 s. Improved device performances, including maximum drain-source current density (IDS, max: 657.6 mA mm-1 → 898.5 mA mm-1), drain-source saturation current density at zero gate bias (IDSS0: 448.3 mA mm -1 → 653.4 mA mm-1), maximum extrinsic transconductance (gm,max: 158.3 mS mm-1 → 219.2 mS mm-1), unity-gain cut-off frequency (fT: 12.35 GHz → 22.05 GHz), maximum oscillation frequency (fmax: 17.55 GHz → 29.4 GHz) and power-added efficiency (P.A.E.: 26.3% → 34.5%) compared to the untreated reference device, have been successfully achieved.

Original languageEnglish
Article number074003
JournalSemiconductor Science and Technology
Volume28
Issue number7
DOIs
Publication statusPublished - 2013 Jul 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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