Electrical Properties of Diamond MISFETs with Submicron-Sized Gate on Boron-Doped (111) Surface

Abstract

ABSTRACTAn H-terminated-surface conductive layer of B-doped diamond on a (111) surface was used to fabricate a metal insulator semiconductor field effect transistor (MISFET) using CaF2, SiO2 or Al2O3 gate insulators and a Cu-metal stacked gate. For a CaF2 gate, the maximum measured drain current (Idmax) was 240 mA/mm and the maximum transconductance (gm) was 70 mS/mm, and the cut-off frequency of 4 GHz was obtained. For a SiO2 gate, Idmax and gm were 75 mA/mm and 24 mS/mm, respectively, and for an Al2O3 gate, these characteristics were 86 mA/mm and 15 mS/mm, respectively. These values are among the highest reported DC and RF characteristics for a diamond homoepitaxial (111) MISFET.