Paper Title
COMPREHENSIVE CHARACTERIZATION OF TiO2/GaN/AlGaN/GaN METAL-OXIDE-SEMICONDUCTOR HIGH-ELECTRON MOBILITY TRANSISTORS

Abstract
Abstract - This study presents TiO2/GaN/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMTs). The studied transistors were grown by metal organic chemical vapor deposition (MOCVD) on silicon (111) substrate. The AlxGa1-xN barrier had thickness of 30 nmwith Al composition of 26%. The two-dimensional electron gas (2DEG) concentration andmobility were measured by Hall Effect measurements on van der Pauw structures. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), capacitance-voltage (C-V), and Raman spectroscopy were used to investigate the TiO2 film.The TiO2 insulator was annealed at different temperatures and in different environments. Experimental results reveal that the device characteristics are improved when the TiO2 film was annealed at 300OC and in nitrogen environment. The two-terminal breakdown voltages, three-terminal off-state breakdown voltages, extrinsic transconductance, high-frequency characteristics, and output power performance of the annealed MOS-HEMTs are enhanced. Furthermore, the gate leakage current and minimum noise figure are reduced. Keywords - TiO2, GaN, MOS-HEMT, insulator.