Surface structure and surface barrier characteristics of boron-doped diamond in electrolytes after CF4 plasma treatment in RF-barrel reactor

We report on the effects of CF4 plasma process in technical RF barrel reactor on surface termination and the resulting electronic surface barrier of boron-doped diamond in electrolytes. The surface characteristics were evaluated for epitaxial single crystalline layers with sub-nm roughness. The capacitance–voltage characteristics of the processes electrodes implied a low electronic barrier at the fluorine-terminated areas, comparable to hydrogen termination in literature. However carbon–oxygen groups were still present on approx. 15% of the surface area after the plasma process. To analyse the electronic barrier of the fluorinated diamond, we proposed an electrical model of two parallel metal-oxide-semiconductor structures. This model included fixed parameters derived from the analysis of a diamond electrode exposed to plasma oxidation.