DC performance improvement of nanochannel AlGaN/AlN/GaN HEMTs with reduced OFF-state leakage current by post-gate annealing modulation

Soumen Mazumder, Zhan Gao Wu, Po Cheng Pan, Ssu Hsien Li, Yeong Her Wang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In this work, the effects of a post-gate annealing (PGA) treatment on the electrical performance of AlGaN/AlN/GaN nanochannel high electron mobility transistors (NC-HEMTs) were analyzed, with various channel widths of 200, 400, 600, and 800 nm for a constant fill factor of 0.45. A systematic improvement in the DC parameters was observed in the NC-HEMTs after PGA treatment at 400 C for 10 min. Secondary ion mass spectroscopy was performed on the 300 C, 400 C, and 500 C for 10 min annealed and as-deposited NC-HEMT to optimize the PGA conditions. It was also verified that annealing at higher temperatures (>400 C) can cause the diffusion of the gate metal (Ni/Au) into the AlGaN/AlN/GaN active layer, which subsequently degrades the device performance. The removal of shallow traps after the PGA treatment, which were created by ICP dry etching, improved the Schottky barrier height (∅B) from 0.42 eV to 1.40 eV and resulted in a significant reduction in the reverse gate leakage current (IG) of approximately more than three orders of magnitude in the NC-HEMT with a channel width of 200 nm. The reduction in the channel resistance after the PGA treatment, correspondingly improved the drift velocity, resulting in a marked improvement in the maximum transconductance (GMMAX) of 34% and considerable incremental increases in the maximum drain current (IDMAX). The NC-HEMT (WNC = 200 nm) with PGA treatment exhibited decent performance, with an IG of 9 × 109 A mm1, an IDMAX of 470 mA mm1, a GMMAX of 140 mS mm1, and an ON/OFF ratio (ION/IOFF) of approximately 1.1 × 107 along with improved gate controllability, i.e. lowering of the subthreshold swing to 69 mV dec1.

Original languageEnglish
Article number095003
JournalSemiconductor Science and Technology
Volume36
Issue number9
DOIs
Publication statusPublished - 2021 Sep

All Science Journal Classification (ASJC) codes

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

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