Field effect type semiconductor device and manufacturing method thereof

摘要

It is an abject to stably and surely perform protection operation of devices. Since the gate threshold voltage VGE(th)S in a sense IGBT cell constituting a sensing circuit is set to have a higher value than the gate threshold voltage VGE(th)M in a main IGBT cell constituting a main circuit, a finite time DELTA t is required from when the gate voltage VGE reaches the gate threshold voltage VGE(th)M until when it reaches the gate threshold voltage VGE(th)S in the turn-on period. Accordingly, the rise of the main current Is of the sensing circuit is delayed from the main current Im of the main circuit. As a result, surge current does not appear in the current Is. As the surge current does not appear in the main current of the sensing circuit, a protection circuit of the device operates stably, and breakdown of the device is surely prevented.