In situ plasma enhanced atomic layer deposition half cycle study of Al_2O_3 on AlGaN/GaN high electron mobility transistors

摘要

A half cycle study of plasma enhanced atomic layer deposited (PEALD) Al_2O_3 on AlGaN is investigated using in situ X-ray photoelectron spectroscopy, low energy ion scattering, and ex situ electrical characterizations. A faster nucleation or growth is detected from PEALD relative to purely thermal ALD using an H_2O precursor. The remote O_2 plasma oxidizes the AlGaN surface slightly at the initial stage, which passivates the surface and reduces the OFF-state leakage. This work demonstrates that PEALD is a useful strategy for Al_2O_3 growth on AlGaN/GaN devices.