GaN metal-oxide-semiconductor high-electron-mobility-transistor with atomic layer deposited Al_2O_3 as gate dielectric

摘要

We report on a GaN metal-oxide-semiconductor high-electron-mobility-transistor (MOS-HEMT) using atomic-layer-deposited (ALD) Al_2O_3 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 Al_2O_3/AlGaN interface is of high quality and the ALD Al_2O_3/AlGaN/GaN MOS-HEMT is of high potential for high-power rf applications. In addition, the high-quality ALD Al_2O_3 gate dielectric allows the effective two-dimensional (2D) electron mobility at the AlGaN/GaN 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).