Modeling inductive switching characteristics of high-speed buffer layer IGBT

In this study, a physics-based compact model for high-speed buffer layer insulated gate bipolar transistor (IGBT) is proposed. The model utilizes the 1-D Fourier-based solution of ambipolar diffusion equation (ADE) implemented in MATLAB and Simulink. Based on the improved understanding on the inductive switching behavior of a high-speed buffer layer IGBT, the ADE is solved for all injection levels instead of high-level injection only as usually done. Assuming high-level injection condition in the buffer layer, the excess carrier transport, redistribution and recombination in the buffer layer are redescribed. Moreover, some physical characteristics such as the low conductivity of N-base at turn-on transient and free holes appeared in the depletion layer during turn-off process are also considered in the model. Finally, the double-pulse switching tests for a commercial field stop IGBT and a light punch-through carrier-stored trench bipolar transistor are used to validate the proposed model. The simulation results are compared with experiment results and good agreement is obtained.