Effects of argon plasma pretreatment on polar and nonpolar GaN/Al2O3 interface

Influence of argon (Ar) plasma pretreatment on polar and nonpolar GaN surface before the deposition of Al ₂ O ₃ dielectric is investiged. The interface trap density (Dit) of polar (c-plane) GaN MOS capacitor with Ar plasma treatment is dramatically lower than that without plasma treatment. In contrast, the Dit of nonpolar (m-plane) GaN MOS capacitor with Ar plasma treatment is higher than that without plasma treatment, indicating that the polar and nonpolar GaN have differenent surface charges and chemical states.