VDMOS modeling for IC CAD

The VDMOS physical modeling method is studied, and then a VDMOS physical model is proposed for IC CAD. In this model, for the region whose cross-section area of electron flow is variable, a differential equation for the vertical electric field, which considers the high electric field´s strong influence on the electron mobility, is established. Moreover, when the nonuniform electron concentration distribution is considered, this differential equation is solved by the analytical method. In addition, for the region whose cross-section area of electron flow is invariable, the analytical formula of vertical electric field is derived approximately by proper simplification. The calculation results show that in comparison to the Yeong-seuk Kim et al´s model, the calculation precision of this model is greatly improved. Especially when both the gate voltage and the drain voltage are high, its improvement is remarkable.