Semiconductor switch

Claim 1

A SEMICONDUCTOR SWITCHING DEVICE CAPABLE OF BEING SWITCHED BETWEEN A NORMALLY HIGH IMPEDANCE STATE AND A LOW IMPEDANCE STATE BY APPLICATION OF A SWITCHING VOLTAGE INCLUDING IN COMBINATION, A. A BODY OF SEMICONDUCTOR MATERIAL HAVING (A) FOUR REGIONS OF ONE AND THE OPPOSITE CONDUCTIVITY TYPE INTERLEAVED TO DEFINE THREE PN JUNCTIONS THEREBETWEEN, B. A PAIR OF MAIN CURRENT CARRYING ELECTRODES EACH IN LOW RESISTANCE OHMIC CONTACT WITH ONE OF THE EXTERNAL REGIONS OF SAID FOUR REGIONS WHEREBY A MAIN CURRENT PATH IS PROVIDED THROUGH SAID FOUR REGIONS AND THREE PN JUNCTIONS AND ONLY ONE OF SAID JUNCTIONS IS REVERSE BIASED FOR A VOLTAGE OF ONE POLARITY APPLIED BETWEEN SAID PAIR OF MAIN CURRENT CARRYING ELECTRODES, (A) SAID PAIR OF MAIN CURRENT CARYING ELECTRODES HAVING MAJOR PORTIONS DIRECTLY OPPOSITE EACH OTHER WHEREBY A MAJOR COMPONENT OF SAID DEVICE MAIN CURRENT PATH IS SUBSTANTIALLY PERPENDICULAR TO SAID THREE PN JUNCTIONS, C. A FIFTH REGION OF OPPOSITE CONDUCTIVITY TYPE FORMED IN ONE OF SAID EXTERNAL REGIONS OF SAID BODY OF SEMICONDUCTOR MATERIAL AND REMOTE FROM THE MAIN CURRENT CARRYING ELECTRODE IN OHMIC CONTACT THEREWITH, (A) SAID FIFTH REGION FORMING A GATE PN JUNCTION WITH THE ADJACENT EXTERNAL REGION AND PROVIDING TRANSISTOR ACTION WITH THE NEXT ADJACENT ONE OF SAID THREE PN JUNCTIONS AND D. A THIRD ELECTRODE IN LOW RESISTANCE OHMIC CONTACT WITH SAID FIFTH REGION THEREBY TO FORM A GATING ELECTRODE FOR THE SEMICONDUCTOR SWITCHING DEVICE WHEREBY SAID SWITCHING DEIVCE IS SWITCHED TO ITS LOW IMPEDANCE STATE UPON APPLICATION OF A VOLTAGE TO SAID THIRD ELECTRODE WHICH IS BETWEEN THAT APPLIED ACROSS THE MAIN CURRENT CARRYING ELECTRODES.