Surface electronic properties on boron doped (111) CVD homoepitaxial diamond films after oxidation treatments

Surface electronic properties on oxidized boron (B) doped (111) homoepitaxial diamond films are investigated by Hall effect measurements and Schottky junction characterizations. Surface electronic properties on (111) diamond strongly depend on annealing treatments after wet-chemical oxidation, whereas for those on (001) diamond no change due to annealing can be detected. Hall effect results show that a p-type surface conductive layer (SCL) exists on (111) diamond surface in air after wet-chemical oxidation followed by annealing in Ar atmosphere (WO–AN) above 300 °C, but does not if only wet-chemical oxidation or air-oxidation is applied. This SCL disappears at annealing temperature above 350 °C in air. Schottky junction characteristics suggest that the Fermi level is unpinned at the (111) surface after WO–AN. Surface electronic characteristics on (111) diamond after WO–AN are similar to those generated by hydrogen termination.