A new physical power MOSFET model for improved simulation in power electronic design

Abstract

A physically based power MOSFET model is derived based on the charge-sheet analysis. This is the first time a charge-sheet approach has been successfully used in modeling a power MOSFET. The continuous nature of the charge-sheet model allows for the development of a continuous I-V model for the power MOSFET from subthreshold to saturation. The generalized form of the charge-sheet model enables the physical modeling of the nonuniform doping through the MOS channel region of the power MOSFET. A physical model of the power MOSFET drift region is combined with the channel model to give a complete physical system of equations which is solved numerically. The model includes detailed calculations of the drift region parameters including the variation of the internal depletion widths with external bias. The physical, continuous behavior of the model provides easy extraction of small signal parameters and interelectrode capacitances. Test measurements of real power MOSFETS are used as a comparison to support the model results.