Gate Metal Interface on Hydrogen-terminated Diamond FETs

Abstract

Hydrogen surface termination is widely used as a p-type doping in diamond semiconductors, but the p-type conduction mechanism is still controversial. In this study, we found an energy barrier for holes between the gate and the two-dimensional hole channel on the hydrogen-terminated diamond surface from FET characteristics. Separately we confirmed an interfacial layer between the gate metal layer and hydrogen-terminated diamond surface from cross-sectional transmission electron microscopic observation. We conclude that during metal evaporation on hydrogen-terminated diamond surface, metal atoms diffuse through point defects in the subsurface layer, and eventually the interfacial layer forms there.