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Vertical heterojunction field‐effect transistors utilizing re‐grown AlGaN/GaN two‐dimensional electron gas channels on GaN substrates

2010; Wiley; Volume: 8; Issue: 2 Linguagem: Inglês

10.1002/pssc.201000439

1862-6351

Seiji Yaegassi, Masaya Okada, Yuu Saitou, Mitsunori Yokoyama, Ken Nakata, Koji Katayama, Masaki Ueno, Makoto Kiyama, Tsukuru Katsuyama, Takao Nakamura,

Semiconductor materials and devices

Abstract Vertical heterojunction field‐effect transistors (VHFETs) utilizing re‐grown AlGaN/GaN two‐dimensional electron gas (2DEG) channels on free‐standing GaN substrates have been developed. The VHFETs exhibited a specific on‐resistance (RonA) of 7.6 mΩcm 2 at a threshold voltage (V th ) of ‐1.1 V and a breakdown voltage (VB) of 672 V. The breakdown voltage and the figure of merit (VB 2 /RonA) are the highest among those of the GaN‐based vertical transistors ever reported. It was demonstrated that the threshold voltage can be controlled by the thickness of AlGaN layers and Al concentration. A normally‐off operation was achieved with a 10‐nm‐thick Al 0.2 Ga 0.8 N layer. The possibility that VHFET with smaller current collapse phenomena than planar HEMT was revealed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)