Formation of high-quality SiO2/β-Ga2O3(001) MOS structures: The role of post-deposition annealing

We investigated the effect of post-deposition annealing on the electrical characteristics of SiO2/β-Ga2O3(001) MOS structures. While oxygen annealing effectively improves the interface properties, it induces acceptor defects in Ga2O3, leading to a decrease in net donor density. With the combination of oxygen and nitrogen annealing, carrier compensation was suppressed, and a low interface state density of about 1 × 1011 cm−2 eV−1 was obtained near the conduction band edge of Ga2O3. High immunity against positive gate bias stress was also confirmed.