XPS study of dependence of Au/6H-SiC Schottky barrier height on carrier concentration

Abstract

SiC is a wide band gap semiconductor attractive for use in high-frequency and highpower devices (FET's and IMPATT's). To realize such devices, the Schottky contact is preferable to p-n junctions because this enables low-temperature processing and facilitates further improvement of device performance. Since the performance of Schottky-based devices depends on barrier height, the optimum barrier height leading to high performance should be investigated in detail. It has been established that barrier height depends on metal work function and SiC polytype, orientation, crystallinity and the surface treatment process before the contacts formation, To the authors knowledge, however, no data have been reported for barrier heights dependence on carrier concentration. In the present work we report a Au/n-6H-SiC contacts Schottky barriers height dependence on uncompensated donor concentration (N/sub d/-N/sub a/). The barrier heights were determined by capacitance-voltage (C-V) and X-ray photoelectron spectroscopy (XPS) techniques.