A Novel Lumped-Charge Model for Insulated Gate Bipolar Transistor Based on Dynamic Charge Control

Abstract

The lumped-charge (LC) model of insulated-gate bipolar transistor (IGBT) provides an effective and efficient way to study its characteristics. However, the quasi-static assumption of the charge-control equation used in existing LC models will impair the accuracy of the model during the switching transient. Thus, in this paper, a dynamic charge-control (DCC) equation that provides a direct solution of the derivative of LC with time is proposed to determine the more precise charge dynamics. In this way, the redistribution effect of charge dynamics arising from moving boundaries can be well accounted for. Moreover, a charge concentration expression for a planar-gate structure as a function of the intercell region geometry is derived to incorporate the 2-dimensional (2-D) excess carrier distribution at the MOS side. This expression is integrated into the proposed IGBT model to improve the boundary condition and provide a better description of excess carrier dynamics. The effectiveness of the proposed model is verified by comparison with the existing LC model and TCAD simulation under the premise of known device parameters. The accuracy of the proposed model is further verified by experiments including both the static and transient characteristics and compared with the existing LC IGBT model using the same advanced parameter extraction.