A simple two-dimensional model for IGFET operation in the saturation region

A model is developed for an IGFET operating in saturation and accounting for the two-dimensional potential distribution in the section of the surface space-charge region adjacent to the drain. This section is treated as a volume obeying Gauss´s law, thereby enabling the charge contained in it to be related to the integral of the electric displacement density normal to its surface without the need to consider the detailed distribution of charge inside. The resulting model shows, explicitly, the dependence of device output characteristics on applied potentials, geometric and processing parameters. It is also shown that by making adequate approximations, simple yet accurate forms of the model are obtained. The accuracy of the model is demonstrated by comparisons between calculated and measured device output characteristics.