GaN-based metal-oxide-semiconductor field-effect transistors

Various fabrication processes including (NH₄)₂S_x surface treatment and photoelectrochemical oxidation were used to fabricate GaN-based metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs). The DC performances, high frequency performances and noise performances of the resulting GaN-based planer and gate-recessed MOS-HEMTs were measured. In view of the nearly similar lattice constant and the same wurtize crystalline structure between ZnO and GaN-based semiconductor, the ZnO insulator was deposited on the GaN-based epitaxial layers of the HEMTs using a vapor cooling condensation system. The ZnO insulator was used as the gate insulator of the GaN-based MOS-HEMTs. The performances of the ZnO/GaN-based MOS-HEMTs were also measured.