Effects of γ-irradiation on electrical characteristics of power vdmos transistors

In this paper we present the results of both experimental investigation and analytical modelling of γ-irradiation effects on basic electrical characteristics of power VDMOS transistors. First, an analytical model that yields the drain current and transconductance dependencies on gate oxide charge density is developed. The experimental data are utilized to establish an analytical relation between the absorbed dose of γ-irradiation and corresponding effective density of gate oxide charges, as well as to extract the values of model parameters. Drain current and transconductance of VDMOS devices are then modelled as the functions of irradiation dose. Finally, the results of modelling are compared with experimental data.