Polysilicon-Contacted Thin Emitter Thyristors

In this paper, we report detailed theoretical analysis of turn-off time and on-state voltage drop in the new type of polysilicon-contacted thin emitter thyristor, studied using the asymmetrical pin diode model and through comparisons with conventional thyristors. The numerical calculations and experimental results showed that for a suitable thickness and total impurity amount of the thin emitter, not only can the turn-off time be shortened by a factor of around 1.5 compared with that of conventional thyristors, but also the on-state voltage drop of the devices is lower than that of conventional thyristors. When the lifetime of the minority carriers in the n B base was decreased to a suitable value, the turn-off time of the devices could be further shortened, up to 1/2.5-1/3 that of conventional thyristors, without deterioration of the on-state properties. In addition, turn-on properties of the new devices are discussed.