Monolithic compound thyristor with a pilot portion having a metallic electrode with finger portions formed thereon

Claim 1

A semiconductor switching device which is highly sensitive to gate signals and which is capable of withstanding very high rates of current increase comprising: a semiconductor body having first, second, third, and fourth contiguous regions of alternate conductivity type forming junctions therebetween, said first region lying along an end surface of said semiconductor body and being laterally divided by said second region adjacent thereto into a central annular segment and a concentrically arranged, laterally spaced principal current carrying segment, first main current carrying electrode means associated with said principal current carrying segment of said first region, second main current carrying electrode means associated with said fourth region, said second region lying along said end surface of said semiconductor body centrally of said annular segment and between said annular segment and said principal current carrying segment, said second region having finger portions along said end surface extending outwardly toward the periphery of said semiconductor body and said principal current carrying segment extending inwardly along said end surface beTween said finger portions, a pilot electrode overlying said central annular segment of said first region and extending outwardly to overlie said second region between said annular segment and said principal current carrying segment, said pilot electrode including metallic fingers overlying said finger portions of said second region, and gate means associated with said second region centrally of said central annular segment.