RF characteristic of MESFET on H-terminated DC arc jet CVD diamond film

Abstract

Diamond has been considered to be a potential material for high-frequency and high-power electronic devices due to the excellent electrical properties. In this paper, we reported the radio frequency (RF) characteristic of metal-semiconductor field effect transistor (MESFET) on polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD). First, 4in polycrystalline diamond films were deposited by DC arc jet CVD in gas recycling mode with the deposition rate of 14μm/h. Then the polished diamond films were treated by microwave hydrogen plasma and the 0.2μm-gate-length MESFET was fabricated by using Au mask photolithography and electron beam (EB) lithography. The surface conductivity of the H-terminated diamond film and DC and RF performances of the MESFET were characterized. The results demonstrate that, the carrier mobility of 24.6cm2/Vs and the carrier density of 1.096×1013cm−2 are obtained on the surface of H-terminated diamond film. The FET shows the maximum transition frequency (fT) of 5GHz and the maximum oscillation frequency (fmax) of 6GHz at VGS=−0.5V and VDS=−8V, which indicates that H-terminated DC arc jet CVD polycrystalline diamond is suitable for the development of high frequency devices.