Fast gate turn-off in a merged thyristor-like structure

A concept of a merged thyristor-like structure which consists of two parts with different base gains is introduced. The high gain (HG) part serves as a source of an opening current for the low gain (LG) part and promotes it to the conducting open state so that the LG part becomes an additional channel for the total current flowing through the structure. During the turn-off process, the LG part serves as a source of the additional blocking current for the HG part, improving the turn-off characteristics of the merged structure. An analytical approach is developed to describe these inhomogeneous structures and their gate turn-off processes. The stationary distributions of the current density in the merged structures are calculated. The storage times and turn-off gains for homogeneous and merged structures are estimated. It is shown that the merged structures exhibit better turn-off characteristics in comparison with homogeneous structures. The direct two-dimensional simulations demonstrate faster turn-off in the merged structure and determine the regimes of operation where the effect can be reliably observed.