650 mW/mm output power density of H-terminated polycrystalline diamond MISFET at 10 GHz

In this work, metal-insulator-semiconductor field effect transistors (MISFET) with gate length of 350 nm were fabricated on hydrogen-terminated polycrystalline diamond by a self-aligned process. Aluminium film with thickness of 2 nm was evaporated on the sample and formed self-oxidised alumina to act as the gate dielectric. The devices show good direct current and radio frequency performances with a maximum frequency of oscillation (f(max)) of 34 GHz and continuous-wave output power density of 650 mW/mm at 10 GHz.