Abstract: The reverse snapback phenomena (RSP) on I-V characteristics of static induction thyristors (SITH) are physically researched.The I-Vcurves of the power SITH exhibit reverse snapback phenomena,and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value.The RSP I-Vcharacteristics of the power SITH are analyzed in terms of operating mechanism,double carrier injection effect,space charge effect,electron-hole plasma in the channel,and the variation in carrier lifetime.The reverse snapback mechanism is theoretically proposed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented.The computing results are compared with the experiment values.

Key words: power static induction thyristor, reverse snapback, electron-hole plasma, lifetime, injection level