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

摘要

An 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 CaF_2, SiO_2 or Al_2O_3 gate insulators and a Cu-metal stacked gate. For a CaF_2 gate, the maximum measured drain current (I_(dmax)) was 240 mA/mm and the maximum transconductance (g_m) was 70 mS/mm, and the cut-off frequency of 4 GHz was obtained. For a SiO_2 gate, I_(dmax) and g_m were 75 mA/mm and 24 mS/mm, respectively, and for an Al_2O_3 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.