Effects of Cl passivation on Al2O3/GaN interface properties

Abstract

We investigated the effects of a HCl-based cleaning (SC2) and post-deposition annealing (PDA) on an Al2O3/GaN interface and electrical properties. X-ray photoelectron spectroscopy revealed the existence of the Cl atoms near the interface after the Al2O3 deposition and subsequent PDA, resulting in a band bending at the GaN surface. A C–V curve of a MOS capacitor with the Al2O3/GaN interface with SC2 was shifted toward the positive bias direction compared with that without SC2. It was found that PDA induced negative shifts of the C–V curves, and that the SC2 treatment increases interface trap density at the Al2O3/GaN interface. These results indicate that the Cl termination of the GaN surface has clear impacts on the interface and electrical properties.