Saturated velocity model of MESFET in the presence of non-uniform distribution of channel impurities and interface states at the gate contact

Abstract

A comparative analysis of the electrical properties of a metal-semiconductor field effect transistor operated in the region of electron velocity saturation has been studied for different types of impurity profiles and taking into consideration the effects of interface states and interfacial layer at the gate contact of the device. Particularly, the power law, exponential and Gaussian impurity profiles in the channel have been considered. The variations of space charge density and depletion layer width with drain voltage and interface state density for the above impurity profiles have been studied relative to that of uniform distribution of doping. The expressions for drain current for these doping profiles have been derived. The normalized current relative to that of uniform distribution of impurities has been studied as a function of drain voltage and interface state density for the respective doping profiles.