Investigation of High-k/In_xGa_1-xas interfaces

The quality of the high-k/In_xGa_1-xAs interface is a crucial factor in achieving high electron mobility compound semiconductor field effect transistors. Capacitance and conductance characterisation methods were employed to evaluate different high-k/InGaAs interfaces. This paper will first discuss the specificity of capacitance voltage characteristics of compound semiconductor MOS structures, and then the recent progress in the study of high-k/In_xGa_1-xAs interfaces will be presented. The capacitance and conductance measurements are combined to provide a picture of the interface state density. We have also investigated the merit of using intermediate k value dielectrics such as Al₂O₃ and MgO as interface control layers between the semiconductor and the main high k layer.