Charge redistribution at GaN–Ga 2O 3 interfaces: a microscopic mechanism for low defect density interfaces in remote-plasma-processed MOS devices prepared on polar GaN faces

Abstract

Interfacial defect densities are typically two orders of magnitude higher at [III–V]–dielectric interfaces than at Si–SiO 2 interfaces. This paper demonstrates GaN devices with significantly reduced interfacial defect densities using a two-step remote plasma process to form the GaN–dielectric interface and then deposit the dielectric film. Separate plasma oxidation and deposition steps have previously been used for fabrication of aggressively scaled Si devices. Essentially, the same 300°C remote plasma processing has been applied to GaN metal–oxide–semiconductor (MOS) capacitors and field effect transistors (FETs). This paper (i) discusses the low-temperature plasma process for GaN device fabrication, (ii) briefly reviews GaN device performance, and then (iii) presents a chemical bonding model that provides a basis for the improved interface electrical properties.