One-dimensional analysis of turnoff phenomena for a gate turnoff thyristor

Turnoff phenomena for a one-dimensional gate turnoff thyristor (GTO) are investigated using exact numerical solutions of a full set of semiconductor device equations. It is shown that the time responses of the hole and the electron densities around the center junction J2 are responsible for the dynamic behavior of the GTO. The storage time almost corresponds to the time period required for J2 to come out of saturation. The fall time is the period from the coming out of saturation of J2 to the point when the cathode emitter junction recovers. Time variations in the rates of replenishment and removal of holes in the p-base during the dynamic turnoff process are discussed, and an understanding of the switching mechanism, which is not obtainable in the generally used static transistor analogy, is obtained. Though a one-dimensional model is employed in this paper, it still provides a great deal of insight into the device´s operation.