A filamentation-free insulated-gate controlled thyristor and comparisons to the IGBT

An insulated-gate controlled thyristor is presented which has a saturating on-state current characteristic and a stable homogeneous current distribution during turn-on and turn-off. The design of the device and a proposed fabrication-process is discussed. The new device has the robust qualities of the IGBT (current saturation, homogeneous current distribution, insulated gate control), and the four-layer thyristor structure allows for a strong reduction in losses compared to the IGBT. A comparison by simulation for high-voltage devices shows that the losses can be reduced by a factor of 2-3 at 3 kV switching and by a factor of 4 at 6 kV switching, as compared to an optimized planar IGBT structure. We also show simulations comparing the stability of these devices against dynamic avalanche-induced current filamentation instabilities