Threshold voltage for GaAs MESFET with a recoil-implanted channel profile

Calculations of threshold voltages and their variations with respect to fluctuations in the substrate dopant density and the channel depth were performed for a recoil-implanted profile of a GaAs MESFET. It was observed that for these very shallow channels, the range of threshold voltages obtained was considerably smaller for different nitride thicknesses and there was a noticeable reduction in the sensitivity of the threshold voltage to fluctuations in the substrate parameters. The implant depth was the crucial parameter in the determination of the threshold voltage and its sensitivity, although in recoil implantation the surface dopant density appeared to be the dominant parameter