Electrically Isolated Metal-Semiconductor Field Effect Transistors and Logic Circuits on Homoepitaxial Diamonds

Isolated metal-semiconductor field effect transistors (MESFETs) have been fabricated on homoepitaxial diamonds grown by microwave plasma chemical vapor deposition. Source, drain and channel regions are fabricated using the surface p-type semiconductive layer unique to hydrogen-terminated diamond surfaces. Other areas are irradiated by an argon beam to obtain highly resistive regions. The maximum transconductance of the isolated MESFETs with 7 µ m gate length is 4.5 mS/mm, which is comparable to that of silicon MOSFET with the same gate length. NOT, NAND, NOR, and R-S flip-flop circuits have been fabricated for the first time on diamond using enhancement-mode active loads.