ELECTRICAL-PROPERTIES OF AL CAF2/I-DIAMOND METAL-INSULATOR-SEMICONDUCTOR FIELD-EFFECT-TRANSISTOR FABRICATED BY ULTRAHIGH-VACUUM PROCESS/

In order to avoid oxygen contamination on the diamond surface as far a s possible during the device process, the diamond metal-insulator-semi conductor field-effect transistor (MISFET) was prepared by a reduced-o xygen process including an ultrahigh vacuum (UHV) process for the firs t time, and its electrical properties were investigated in detail. Acc ording to the results, it was found that the electrical properties of the MISFET were improved to a great extent in comparison with those of conventional diamond MISFETs. The observed effective mobility (mu(eff )) was 400 cm(2)/V.s at room temperature, which is the highest value o btained until now in the diamond FET at room temperature. Besides, the measured transconductance (g(m)) and surface state density (N-ss) of the device operation region was 5 mS/mm and similar to 10(10)/cm(2)/.e V, respectively, which is also comparable with conventional Si metal-o xide-semiconductor field-effect-transistors (MOSFETs) with the same ga te length (L-g = 30 mu m).