Gallium Oxide Semiconductor MOS Capacitors With Atomic Layer Deposited High-K Dielectrics

Beta-Gallium Oxide (β-Ga2O3) has garnered significant interest as a semiconductor for high-power and optical devices because of its wide bandgap and its availability in wafer form, in addition to supporting a wide range of epitaxial materials with various dopants. A variety of dielectric materials are available for creating MOS devices using β-Ga2O3 substrates. A suitable dielectric must have a high dielectric constant and a sufficient bandgap offset to prevent Fowler-Nordheim or direct tunneling of electrons. Al2O3, SiO2, and HfO2 are potential candidates due to relatively high band offsets with β-Ga2O3 and conceivable ease of integration. This work is composed of several studies which investigate the effects of surface treatments, such as chemical cleaning, plasma etching, or heat treatments of the β-Ga2O3/ dielectric interface, on MOS capacitor performance using capacitance-voltage and current-voltage analysis techniques. The purpose of this research is to contribute to the overall development of β-Ga2O3 technology especially in the areas of dielectric interfaces and oxide reliability.