Abstract
Two-dimensional simulation for bi-directional thyristors is carried out to clarify switching mechanisms. The switching process can be divided into four regions; (1) an avalanche breakdown region, (2) a negative resistance region, (3) a low current ON-state region and (4) a high current ON-state region. This paper considers the changes in current path and carrier distribution corresponding to the four regions for the thyristor. A way to apply the two-transistor model is proposed after analyzing inherent electron and hole currents in this thyristor. Furthermore, the effects of Auger recombination and band-gap narrowing on current-voltage characteristics are shown. We intend to apply these results to the design of semiconductor lightning surge protectors.
