Fabrication of diamond in-plane-gated field effect transistors using oxygen plasma etching

Diamond dual in-plane-gated field effect transistors with very low gate leakage current have been fabricated on an undoped hydrogen-terminated diamond p-type surface using oxygen plasma etching. Adjusting the threshold voltage optimally by one side gate, lateral electric field from the other side gate modulates the channel conductance. The oxygen plasma etching of 60 nm in depth fully isolated the channel of the hydrogen-terminated diamond surface conductive layer from the side gates resulting very low gate leakage current (< 1 pA at -60 V) at room temperature. This feature provides a necessary condition for the fabrication of diamond single-hole transistors operated at room temperature.