Numerical simulation for estimating the optically controlled characteristics of an ion-implanted Si-MESFET

Abstract

The paper presents a numerical model for determining the dc characteristic of an ion-implanted Si-MESFET under optically controlled condition. The model accounts for all the major effects that shape the characteristics of the device in the illuminated condition. For the first time a model has been developed for the optically controlled MESFET with non-uniformly doped channel to determine the channel voltage profile and the variation of the gate depletion width as well as the substrate depletion width in the channel as a function of position between source and drain. The model can also be utilised for estimating the drain current - drain voltage characteristics and the transfer characteristics of the device under dark and the illuminated condition. It also enables one to calculate the transconductance and the gate to source capacitance which are directly related to the cut-off frequency of the device.