Silicon Carbide Thyristors

Abstract

The basic structure and operation of the thyristor are discussed briefly in Chap. 2 and in more detail in the textbook [1]. The thyristor contains two coupled bipolar transistors that provide an internal positive feedback mechanism that allows the device to sustain itself in the on-state. Analytical models were provided in Chap. 2 for all the operating modes of the thyristor. These models are applicable to the silicon carbide devices discussed in this chapter. The motivation for the development of thyristors from silicon carbide originates from the high on-state voltage drop and slow switching speed of the high-voltage silicon devices. In Chap. 2, it was demonstrated that even a 10-kV silicon thyristor structure has a relatively high on-state voltage drop (close to 3 V) even when the high-level lifetime in its drift region is 100 μs. In the case of silicon carbide devices, the width of the drift region can be greatly reduced (about ten times) when compared with a silicon device with the same voltage rating. This allows obtaining devices with much faster switching speed.