Controllable semiconductor devices with a negative current-voltage characteristic and method of their manufacture

Claim 1

A CONTROLLABLE SEMICONDUCTOR DEVICE HAVING A NEGATIVE CURRENT VOLTAGE CHARACTERISTIC BETWEEN TWO MAIN ELECTRODES, COMPRISING A SEMICONDUCTOR MONOCRYSTAL HAVING A MAIN PORTION OF ONE CONDUCTANCE TYPE AND THREE MUTUALLY SEQUENTIAL REGIONS ADJACENT TO SAID MAIN PORTION, THE TWO OUTER ONES OF SAID REGIONS HAVING HIGH EXTRINSIC CONDUCTANCE OF THE OPPOSED TYPE AND FORMING RESPECTIVE P-N JUNCTIONS WITH THE MAIN PORTION, THE INTERMEDIATE REGION BEING FORMED AS AN INVERSION LAYER BENEATH AN OXIDE COATING BETWEEN SAID OUTER REGIONS AND HAVING LOW CONDUCTANCE DIFFERENT IN TYPE FROM THE CONDUCTANCE OF SAID MAIN PORTION, SAID TWO OUTER REGIONS BEING CLOSELY SPACED FROM EACH OTHER A DISTANCE SUFFICIENT TO PREVENT MUTUAL CONTACT OF SAID JUNCTIONS AT VOLTAGES BELOW THE BREAKDOWN LIMIT, SAID INTERMEDIATE REGION BEING FURTHER CHARACTERIZED BY HAVING A GEOMETRIC RESTRICTION REMOTELY LOCATED WITH RESPECT TO THE LOCALITY OF THE PREDETERMINED POINT OF HIGHEST FIELD STRENGTH IN THE INTERMEDIATE REGION; AND FOUR CONTACT ELECTRODES ONE EACH ON SAID TWO OUTER REGIONS FORMING THE MAIN ELECTRODES, ONE ON SAID OXIDE COATING ON TOP OF SAID INTERMEDIATE REGION AND ONE ON SAID MAIN PORTION.