Pseudo-Two-Dimensional Numerical Simulation of A 0.25 μm Irradiated MOSFET in Conjunction with Extensive Mobility Modeling

Abstract

A pseudo two dimensional numerical model of a sub-micron Metal-Oxide-Semiconductor-Field-Effect-Transistor (MOSFET) has been developed to examine theoretically the effect of ionising radiation on the threshold voltage and the global output characteristics of the device. The various scattering mechanisms responsible for the change in the mobility of the charge carriers have been considered. The radiation induced change in the flat-band voltage has been utilised to estimate the change in the surface potential and hence the threshold voltage of the device in the irradiated condition. The drain current-drain voltage (lD-VD) characteristics of the device in the irradiated condition has been estimated numerically by taking into consideration the radiation induced changes in the surface potential and mobility of the carriers in the surface channel. The model developed here has been validated by reported experimental result for the pre-irradiated case. It is seen that the new model gives a better fit to experimental result as compared to standard SPICE model (LEVEL 3). The model can be used as a basic tool for characterising sub-micron MOSFET in the pre- and post-irradiated condition.