Focused ion implantation of gallium arsenide metal–semiconductor field effect transistors with laterally graded doping profiles

Abstract

Implantation with finely focused beams of dopant ions scanned under computer control enables laterally graded doping profiles to be formed. A 150-nm-diam beam of silicon ions from a gold–silicon–beryllium liquid metal ion source has been used to fabricate GaAs metal–semiconductor field effect transistors (MESFET’s) incorporating a number of different laterally graded doping profiles. It is seen experimentally that, when compared with uniformly implanted devices, these MESFET’s display increased available output power and transductance.