Model of MOS field transistor in the range of small source-drain polarization voltages with frequency dispersion of the capacitance of the MIS structure

A linear analysis of a model of an MOS field transistor with distributed parameters taking into account the frequency dispersion of the capacitance of the metal-insulator-semiconductor structure is performed. Attention is restricted to the case of small source-drain polarization voltages for which one may assume a uniform distribution of parameters in the channel. Analytical expressions are derived for the transistor admittance parameters, and the equivalent circuit for low frequencies is obtained. Theoretical results are supported by measurements of the admittance parameters of a transistor as a function of the gate polarization function with respect to the base and as function of frequency.