Moderate inversion model of ultrathin double-gate nMOS/SOI transistors

Different 1D analytical models for the potential distribution across the silicon film of a double-gate nMOS/SOI device are proposed and compared. Models are based on a double integration of Poisson's equation, which contains both the dopant impurity charges and an approximation of the minority carrier concentration. With the best approximation, a model valid from the subthreshold to the strong inversion region is obtained. It is especially useful in the moderate inversion region where classical models fail. Analytical expressions of the drain current and transconductance are provided at low V-D. The threshold voltage is extracted by the maximum transconductance change method. Good agreement with numerical simulations is achieved.