Thyristor semiconductor device and switching method thereof

The objective of this invention is to provide a semiconductor device having a thyristor that can shorten the turn-off time. A first electroconductive type first semiconductor region 20 is formed on a substrate, and a second electroconductive type second semiconductor region 22, a second electroconductive type third semiconductor region 23, designated as an anode, and a first electroconductive type fourth semiconductor region 24, designated as an anode gate, are formed on the surface layer part of the first semiconductor region. Also, a first electroconductive type fifth semiconductor region 26, designated as a cathode, and a second electroconductive type sixth semiconductor region 25, designated as a cathode gate, are formed on the surface layer part of the second semiconductor region. A gate insulating film 30 and a gate electrode 31 are formed in an upper layer of the second semiconductor region in a region from a boundary of the first semiconductor region and the second semiconductor region to a boundary of the second semiconductor region and the fifth semiconductor region, and an electroconductive layer for input and output is formed in the third semiconductor region, fourth semiconductor region, sixth semiconductor region, and fifth semiconductor region. A thyristor is constituted by the third semiconductor region, the first semiconductor region, the second semiconductor region, and the fifth semiconductor region.