Abstract: An asymmetric gate commutation thyristor model was set up and process and device simulations were done.Simulation results show that the total amount of impurity in the buffer layer or transparent anode is the key to determine the on-state voltage drop of GCT device.The on-state voltage can be reduced by modifying the thickness and doping profile of each layer to control the total amount of impurity. In addition,the influence of the minority carrier lifetime of n-base region on the on-state voltage of GCT device is obviously observed.The dose of electron irradiation is selected with the tradeoff between the turn-off time and on-state voltage of GCT device.