The structure for the symmetric blocking, double-diffused, IGBT was shown on the left-hand side of
Fig. 2.1. A symmetric blocking, trench-gate, IGBT structure is similar to that shown in
Fig. 2.4 without the
N-buffer layer. The analyses and design procedures described below are applicable to both of these gate structures. The first symmetric blocking IGBT was demonstrated in 1982
[2]. Since the development of IGBT products was mainly focused on motor drive circuits operated from a DC power bus, the symmetric structure lay dormant for nearly 20
years because the asymmetric IGBT structure has much more favorable characteristics for motor drive applications. Interest in the symmetric IGBT structure has revived for application ...