Controlled rectifier having auxiliary cathode and slotted main cathode

Claim 1

A controlled rectifier having adjusted di/dt and dv/dt characteristics, and being capable of being fired with a relatively low gate current; said controlled rectifier comprising: a wafer of monocrystalline semiconductor material having first and second parallel surfaces; first, second and third spaced PN junctions sequentially disposed therein; at least a portion of said third PN junction terminating along said first surface of said wafer and dividing said first surface into a first surface region extending atop said third PN junction and into a second surface region; a first main electrode connected to said first surface region of said first surface; a second main electrode connected to said second surface of said wafer; a fourth PN junction disposed beneath said second surface region of said first surface and above said second PN junction; an auxiliary electrode connected to said second surface region atop said fourth junction; a main gate electrode connected to said second surface region adjacent said auxiliary electrode; and an auxiliary gate electrode connected to said auxiliary electrode and to said second surface region of said wafer adjacent to said first main electrode; said auxiliary electrode and said auxiliary gate electrode comprising a common conductive electrode extending across said fourth PN junction; said first main electrode having an edge portion adjacent one edge of said common conductive electrode; said edge portion being slotted; the teeth of said slot extending across said third junction thereby to form a shorted emitter connection; said edge of said common conductive electrode being straight.