GaN metal-oxide-semiconductor high-electron-mobility-transistor with atomic layer deposited Al2 O3 as gate dielectric

Abstract

We report on a GaN metal-oxide-semiconductor high-electron-mobility- transistor (MOS-HEMT) using atomic-layer-deposited (ALD) Al2 O3 as the gate dielectric. Compared to a conventional GaN high-electron-mobility-transistor (HEMT) of similar design, the MOS-HEMT exhibits several orders of magnitude lower gate leakage and several times higher breakdown voltage and channel current. This implies that the ALD Al2 O3 AlGaN interface is of high quality and the ALD Al2 O3 AlGaNGaN MOS-HEMT is of high potential for high-power rf applications. In addition, the high-quality ALD Al2 O3 gate dielectric allows the effective two-dimensional (2D) electron mobility at the AlGaNGaN heterojunction to be measured under a high transverse field. The resulting effective 2D electron mobility is much higher than that typical of Si, GaAs or InGaAs metal-oxide-semiconductor field-effect-transistors (MOSFETs). © 2005 American Institute of Physics.