Thyristor having a secondary emitter electrode and a method for

Abstract

A thyristor structure has a semiconductor body which includes first and second base layers adjacent and contacting one another, a p-emitter layer contacting the first base layer, a first electrode contacting the p-emitter layer, an auxiliary, n-emitter layer contacting the second base layer, a second electrode contacting the auxiliary n-emitter layer and bridging the pn junction between the second base layer and the auxiliary n-emitter layer a n-emitter layer contacting the second base layer and a third electrode contacting the n-emitter layer. At least one current path which can be turned off comprises a metal-insulator-semiconductor structure located at the boundary surface of the semiconductor body which carries the second electrode. The MIS semiconductor structure includes first and second semiconductor regions of the first conductivity type spaced apart with a third semiconductor region of an opposite conductivity type intermediate thereto, all regions extending up to the boundary surface of the semiconductor body. An insulated gate covers the third region and has a control voltage terminal. Portions of the second base layer extends through the n-emitter layer and contact the third electrode at the boundary surface. The structure also includes a trigger electrode carried on the base layer which is adjacent the boundary surface. The thyristor is switched from the block state to the conducting state by the application of a control voltage and the control voltage may simultaneously be applied to the trigger electrode.