Neutral beam etching for device isolation in AlGaN/GaN HEMTs

Fuyumi Hemmi, Cedric Thomas, Yi Chun Lai, Akio Higo, Alex Guo, Shireen Warnock, Jesús A. del Alamo, Seiji Samukawa, Taiichi Otsuji, Tetsuya Suemitsu

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


In this article, we report a suppression of leakage current and an improvement of isolation breakdown voltage on GaN-based high electron mobility transistors (HEMTs) by means of neutral beam (NB) etching. The plasma damage during dry etching process is one of the key reasons for an isolation leakage current, gate leakage current, and current collapse in GaN HEMTs. Since NB etching is virtually free from electrical charges and has few UV photons, it is possible to reduce plasma damage on an etched surface and improve device characteristics. In this work, we introduced NB etching to the device isolation process of GaN HEMTs and characterized isolation leakage currents at DC and step-stress bias conditions. We also measured the breakdown voltages on two-terminal test element arrays. We compared the characteristics with samples etched by conventional plasma-like beam (PB) etching. Our results suggest that NB etching reduces the leakage current through the etched surface of the mesa isolation, which results in superior breakdown voltages.

Original languageEnglish
Article number1600617
JournalPhysica Status Solidi (A) Applications and Materials Science
Issue number3
Publication statusPublished - 2017 Mar 1


  • GaN
  • breakdown voltage
  • high electron mobility transistor
  • leakage current
  • neutral beam etching
  • plasma damage


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