In situ x-ray photoelectron spectroscopy and capacitance voltage characterization of plasma treatments for Al2O3/AlGaN/GaN stacks

We investigate the Al2O3/AlGaN/GaN metal-oxide-semiconductor structure pretreated by O2 anneals, N2 remote plasma, and forming gas remote plasma prior to atomic layer deposition of Al2O3 using in situ X-ray photoelectron spectroscopy, low energy electron diffraction, and capacitance- voltage measurements. Plasma pretreatments reduce the Ga-oxide/oxynitride formation and the interface state density, while inducing a threshold voltage instability.