Abnormal Surge Responses in Bi-directional Thyristors at High Surge Current

Abnormal surge response in bi-directional thyristors at high surge currents is analyzed. This phenomenon presents an abrupt increase in the on-voltage with a peak. As the applied surge current increases, the peak value of the on-voltage becomes higher, and the peak occurrence time decreases. The on-voltage increase is caused by the temperature dependence of Auger recombination and carrier mobility. The decrease in mobility and lifetime governed by the Auger effect are enhanced due to self-heating caused by the surge current. The analysis agrees reasonably well with theoretical considerations.