Gate turn-off capability of depletion-mode thyristors

Experimental results are described which demonstrate the ability to switch a thyristor from its ON state to its OFF state by using a depletion layer formed by the application of gate bias to a trench-gate MOSFET integrated within the thyristor structure. The maximum controllable current is found to be a function of the gate bias voltage, the trench depth, and the ambient temperature. The maximum controllable current can be increased by increasing the trench depth and decreasing the p-base sheet resistance. The maximum controllable current decreases at high temperatures, as in the case of other MOS-bipolar devices, but is significantly better than for previous devices. The absolute values of the maximum turnoff current are well above 1000 A/cm/sup 2/ at room temperature and 500 A/cm/sup 2/ at 200 degrees C.<
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