High‐temperature operation of an AlGaN/GaN HFET on a Si substrate using a thin GaN film

Abstract

An AlGaN/GaN heterostructure on a Si substrate was grown using metalorganic chemical vapor deposition (MOCVD) to fabricate a heterojunction field effect transistor (HFET). A homogenous buffer layer was obtained at 1093 K; a 0.5 μm-thick GaN layer was also obtained without cracking in a 2-inch wafer. We fabricated an HFET using an undoped Al0.3Ga0.7N (20 nm)/undoped GaN (450 nm)/Al0.05Ga0.95N buffer (100 nm) on a p-type Si (111) substrate. The gate length and width were 2 μm and 150 μm, respectively. The distance between the source and drain was 10 μm. The ohmic electrode material was Al/Ti/Au and the Schottky electrode material was Pt/Au. The Schottky breakdown voltage of the gate and the source was over 100 V. It was confirmed that this HFET could be operated at 573 K for over 100 h. We thus demonstrated a high-temperature operation of an AlGaN/GaN HFET on a Si substrate using a very thin film of less than 600 nm. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)