A metal/insulator/semiconducting (MIS) diamond structure employing SrT
iO3/CaF2 composite film as a gate insulator was fabricated and its ele
ctrical properties were investigated by C-V measurement. In the C-V cu
rve, the Al/SrTiO3/CaF2/diamond MIS structure exhibited high capacitan
ce as well as reduction of the surface state on the diamond state. In
addition, the temperature gradient method during the deposition of SrT
iO3 film was very effective to obtain the crack-free composite film of
SrTiO3/CaF2 composite structure.