Improved stability of metal-insulator-diamond semiconductor interface by employing BaF2 insulator film

Diamond metal-insulator-semiconductor (MIS) structures were fabricated by e mploying various fluorides as gate insulator (MgF2, CaF2 and BaF2) and thei r electrical properties were closely investigated by means of C-V measureme nts. The C-V characteristics of a BaF2/diamond structure exhibited outstand ing electrical properties (surface state density less than 2 x 10(10)/(cm(2 ).eV) near the valence bandedge) as compared with the structures obtained u sing other fluorides. From the chemi-physical point of view, the above resu lt might be explained as being due to the reduction of adsorbed-oxygen on t he diamond surface via a strong chemical reaction by the constituent Ba ato ms in the insulator during the film deposition.