Electronic and chemical passivation of hexagonal 6H-SiC surfaces by hydrogen termination

Hydrogenation of 6H-SiC (0001) and (000(1) over bar) is achieved by high-te mperature hydrogen treatment. Both surfaces show a low-energy electron diff raction pattern representative of unreconstructed surfaces of extremely hig h crystallographic order. On SiC(0001), hydrogenation is confirmed by the o bservation of sharp Si-H stretching modes. The absence of surface band bend ing for n- and p-type samples is indicative of electronically passivated su rfaces with densities of charged surface states in the gap of below 7 x 10( 10) cm(-2) for p-type and 1.7 x 10(12) cm(-2) for n- type samples, respecti vely. Even after two days in air, the surfaces show no sign of surface oxid e in x-ray photoelectron spectroscopy. (C) 2001 American Institute of Physi cs.