A new physics based SPICE sub-circuit model for insulated gate bipolar transistors (IGBTs)

Abstract

The paper describes SPICE simulator implementation of a new, physics based, Finite Element Method (FEM) model for semiconductor simulation. The method is based on unidimensional approach that associates each zone of the semiconductor to a sub-circuit capable of implementation, in any general circuit simulator (such as SPICE), in a modular mode. After identification of these zones they are just modelled using subcircuits, which emulate their behaviour. Final model is made connecting them through boundary conditions. Modelling a semiconductor starts with identification of the different zones that constitute the device, such as, low doped, high doped and ohmic zones, narrow bases, and junction and space charge zones. For large and lightly doped zones electron/hole time/space distribution (ambipolar diffusion equation (ADE) solution in space/time) is found solving ADE with the Finite Element Method (FEM). Highly doped emitters as recombination sinks using h parameters. Ohmic zones are modelled with the knowledge of time/space carrier concentration. Models for narrow bases uses charge control principles. Junction and space charge drops models uses, respectively, a Boltzmann approach and Poisson equation.