Four layer controllable semiconductor rectifier with improved firing propagation speed

Claim 1

IN A CONTROLLABLE SEMICONDUCTOR RECTIFIER DEVICE INCLUDING: A MONOCRYSTALLINE SEMICONDUCTOR BODY HAVING FOUR LAYERTYPE ZONES OF ALTERNATINGLY OPPOSITE CONDUCTIVITY TYPES AND WITH THE ONE OF THE INNER ZONES OF SAID SEMICONDUCTOR BODY WHICH BORDERS ON THE ONE OF THE OUTER ZONES OF SAID SEMICONDUCTOR BODY WHICH SERVES AS THE EMITTER ZONE OF THE DEVICE HAVING A PORTION THEREOF WHICH IS TO SUPPORT THE CONTROL ELECTRODE AND EXTENDS TO THE SAME MAJOR SURFACE OF SAID SEMICONDUCTOR BODY AS SAID EMITTER ZONE; A RESPECTIVE LOAD CURRENT ELECTRODE OHMICALLY CONTACTING EACH OF THE TWO OUTER ZONES OF SAID SEMICONDUCTOR BODY; AND A CONTROL ELECTRODE OHMICALLY CONTACTING SAID ONE OF THE INNER ZONES, THE IMPROVEMENT COMPRISING: A HIGHLY DOPED ZONE OF A CONDUCTIVITY TYPE OPPOSITE THAT OF SAID ONE OF THE INNER ZONES FORMED WITHIN SAID PORTION OF SAID ONE OF THE INNER ZONES AND LATERALLY SPACED FROM SAID EMITTER ZONE, SAID HIGLY DOPED ZONE FORMING A PNJUNCTION WITH SAID ONE OF THE INNER ZONES WHICH PNJUNCTION EXTENDS TO SAID MAJOR SURFACE; AND SAID CONTROL ELECTRODE CONTACTING SAID ONE OF THE INNER ZONES AT SAID MAJOR SURFACE AND OVERLYING AND OHMICALLY CONTACTING AT LEAST A PORTION OF SAID HIGHLY DOPED ZONE ALONG SAID SURFACE, SAID CONTROL ELECTRODE BEING POSITIONED SUCH THAT AT LEAST A PORTION OF SAID PN-JUNCTION IS BETWEEN THE CONTROL ELECTRODE AND SAID EMITTER ZONE WHEREBY SAID HIGHLY DOPED ZONE SERVES AS A BARRIER FOR THE CHARGE CARRIERS OF THE CONTROL CURRENT.