High frequency hydrogen-terminated diamond MESFET with an fmax of 103GHz

Abstract

High-quality polycrystalline diamond substrate was used to fabricate diamond MESFETs by a self-aligned process. The fabricated diamond MESFETs with a gate length of 130 nm show good direct current and radio frequency performances, with the maximum saturation source-drain current IDS of 560 mA/mm, the Ion/Ioff ratio of 107, the transconductance of 225 mS/mm, and the current gain cut-off frequency fT of 40.7 GHz and the maximum oscillation frequency fmax of 103 GHz. These results show that the high-quality polycrystalline freestanding diamond is a promising candidate for the investigation of high frequency electronic devices.