Self-aligned NiSi 2 electrode fabrication by MBE and its application to etched-groove Permeable Base Transistor (PBT)

Abstract

A self-aligned NiSi 2 electrode fabrication process was developed. Epitaxial NiSi 2 films were selectively grown on a Si substrate by MBE with a thin SiO 2 film mask. NiSi 2 electrodes were fabricated simultaneously on the bottom and the top surfaces of grooved Si substrates in a self-aligned manner. These electrodes showed good Schottky characteristics. By using this method, etched-groove permeable base transistors (PBTs) were fabricated, where the NiSi 2 layers on the etched grooves were used as gate and source electrodes. The highest mutual conductance ( g m) was obtained as 32 mS/mm, which agreed well with the results of computer simulation.