Hidden emitter switching device

Claim 1

A SEMICONDUCTOR SWITCHING DEVICE, COMPRISING A WAFER OF SEMICONDUCTOR MATERIAL OF ONE CONDUCTIVITY TYPE HAVING UPPER AND LOWER OPPOSED MAJOR SURFACES, SAID WAFER HAVING FOUR ZONES OF ALTERNATELY DIFFERENT CONDUCTIVITY TYPES SUCCESSFULLY INTERPOSED BETWEEN SAID SURFACES, ONE END ZONE COMPRISING A PLURALITY OF REGIONS CONTIGUOUS WITH SAID LOWER SURFACE, SAID END ZONE BEING INSET INTO THE NEXT ADJACENT ZONE SUCH THAT SAID LOWER SURFACE IS COMMON TO BOTH SAID END AND ADJACENT ZONES, SAID NEXT ADJACENT ZONE EXTENDING TO SAID UPPER SURFACE; A CONDUCTIVE LAYER ON SAID LOWER SURFACE ELECTRICALLY INTERNCONNECTING SAID END AND ADJACENT ZONES, BY LAYER BEING FREE OF ANY EXTERNAL ELECTRICAL CONNECTIONS THERETO; A FIRST ELECTRODE ON SAID UPPER SURFACE IN OHMIC CONTACT WITH THE OTHER END ZONE; A SECOND ELECTRODE SPACED FROM SAID ELECTRODE AN SAID UPPER SURFACE; AND MEANS ELECTRICALLY COUPLING SAID SECOND ELECTRODE TO SAID NEXT ADJACENT ZONE, THE THICKNESS, RESISTIVITIES, AND MINORITY CARRIER LIFETIMES OF SAID ZONES BEING SUCH THAT APPLICATIONS OF AN INCREASING VOLTAGE BETWEEN SAID ELECTRODES OF REVERSE POLARITY TO THE CENTRAL JUNCTION BETWEEN THE TWO OF SAID FOUR ZONES ADJACENT THE END ZONES SWITCHES SAID DEVICE FROM A HIGH RESISTANCE TO A LOW RESISTANCE STATE WHEN SAID INCREASING VOLTAGE EXCEEDS THE REVERSE BREAKDOWN VOLTAGE OF SAID CENTRAL JUNCTION AND THE JUNCTION BETWEEN SAID ONE END ZONE AND SAID NEXT ADJACENT ZONE IN INTERNALLY BIASED TO CAUSE CONDUCTION THROUGH ALL FOUR ZONES BY THE INTERNAL VOLTAGE DROP DUE TO THE INITIAL CURRENT FLOW ACROSS SAID CENTRAL JUNCTION.