Suitability Study of Oxide/Gallium Arsenide Interfaces for MOSFET Applications

The suitability of oxide/GaAs interfaces for MOSFET applications has been investigated. Electrical properties of Ga2O3/GaAs interfaces, dielectric stacks utilizing the Ga2O3/GaAs interface, and Al2O3/GaAs interfaces have been studied using a set of independent techniques, including admittance-voltage (ac C-V and G-V at 25°C and 150°C), quasi-static static C-V, photoluminescence intensity (PL-I), and MOSFET I-V measurements. The side-by-side comparison reveals the fundamental differences in their respective data sets. The GdGaO/Ga2O3/GaAs system has been found to exhibit a U-shaped Ditdistribution with a midgap Ditplateau of 2 - 3 × 1011cm-2· eV-1, which has allowed manufacturing GaAs MOSFETs with dc performance close to ideal model predictions. Some other ternary oxides such as GdScO3and LaAlO3can also be deposited on a Ga2O3template without disrupting the Ga2O3/GaAs interface. Beyond GaAs bulk, the use of a surface heterostructure has been investigated, which shifts, in energy space, the mobile charge distribution in the channel layer away from a branch of rising Ditin the vicinity of Ec at the Ga2O3/GaAs interface. In contrast, Al2O3/GaAs(100) interfaces show a typical GaAs native oxide behavior with axGa1-xAs.