Highly Improved Electrical Properties of Diamond Metal-Insulator-Semiconductor Field-Effect-Transistor Prepared by Ultrahigh Vacuum Process

Abstract

In order to prevent oxygen contamination of the diamond surface as much as possible during the device process, a diamond metal-insulator-semiconductor field-effect transistor (MISFET) was fabricated by the ultrahigh-vacuum (UHV) process as well as the reduced-oxygen process, and its electrical properties were investigated in detail. Compared with conventional diamond FETs, the MISFET exhibited great improvement in electrical properties. The observed effective mobility (µ eff ) was 400 cm 2 /V·s at room temperature, which is the highest value obtained to date for the diamond FET at room temperature. According to the drain conductance G D vs surface state density N SS ( G D - N SS ) relation derived in this work, it was found that the surface state density of the MISFET was decreased to a great extent (∼10 10 /(cm 2 ·eV)) in comparison with those of conventional diamond FETs.