Turn-off behaviour of GTO´s: 2-D numerical results compared to IT-radiation patterns

To a steadily growing extent numerical simulation models are utilized for the development and the design of semiconductor power devices. However simulation programs known so far are only to handle under strong restrictions. In this paper a novel 2-dimensional transient simulation system is presented. The special requirements of bipolar power devices are served by the application of dynamic grid generation and adaption in connection with a generalization of the finite difference method. The model is used for a study of the on-state and turn-off behaviour of a GTO with small cathode-elements both with and without anode shorts. Results of numerical simulations will be compared with measured time series of IR-recombination-radiation photographs.