Study Of The Breakover Phenomenon In The I-V Characteristics Of Static Induction Thyristor By Numerical Simulation

Static Induction Thyristor is a kind of high power switch device. Compared with other power device, it has many merits ,such as high switch speed, convenient to turn-off by control of gate bias. However in practice, in the transient of turn-off the super large current will damage the device. Therefore, it is an important theoretical focus that how to obtain the enough high block voltage or block gain meanwhile resolves the wastage efficiently in turn-off transient.The thesis studied the breakover phenomenon in the Ⅰ-Ⅴ characteristics of SITH. We used the numerical simulation, considered the variation of potential, electric field and carrier concentration in SITH, researched and expatiated the rule of increasing current in block-state, the mechanism of breakover phenomenon and the on-state voltage drop. The feature of current variation is also researched in this thesis. The study conclusion accorded with the experimental results.The study results shows that the breakover phenomenon in the Ⅰ-Ⅴ characteristics of SITH is due to the continual decreasing of potential and the continual increasing of anode P-N junction bias, accordingly the high injection formed in the drifting region, which leads to the hole concentration of space charge region near the gate much higher than the ionized acceptor concentration, and the space charge region reduced and can not stand higher voltage.