High-power semiconductor device: a symmetric gate commutated turn-off thyristor

A hgh-power semiconductor device is presented, the symmetric gate commutated turn-off thyristor (SGCT). The current and power dissipation balances among unit cells in an SGCT chp during turn-off operation are analysed by simulation. Using this result, n-emitter widths of the cells are adjusted in inverse proportion to the distance between the cells and the gate contact point on the chip. The current uniformity among the cells is realised for the SGCT chip. The relation between dynamic and static characteristics of an SGCT and the local lifetime controlled position in the n-base layer are investigated. The multi-energy proton lifetime control technology is thus developed: the SGCT has two low lifetime areas in the n-base layer, and those lifetimes are controlled independently by proton irradiation. The improved double-positive bevel is adopted for ensuring the high blocking symmetric voltage and its stability. This SGCT is expected to contribute to such areas as high-voltage and high-power convertors, inverters and switches, because of its high symmetric voltage, high-current capability, low-power dissipation and fast switchng characteristics.