Novel InP metal-insulator-semiconductor structure having an ultrathin silicon interface control layer

A novel oxide-free InP MIS structure, having an ultrathin Si3N4/Si layer produced by ECR partial nitridation of MBE Si layer, is proposed on the basis of the modified silicon interface control layer (Si ICL) concept, and is successfully realized. Use of ECR plasma allowed monolayer level control of Si ICL thickness so that the previous problem that a large portion of the conduction band and the valence band states of the Si ICL fall in the energy gap of InP was avoided by making the Si ICL so thin that all the states in the valence band surface quantum well were pushed away due to the quantum effect. In-situ XPS measurements confirmed formation of a well-defined Si3N4/Si ICL interface structure. Capacitance-voltage measurements showed a broad U-shaped interface state density (Nss) distribution with a minimum of 2×1010 cm-2 eV-1.