Field-effect transistors

Claim 1

A FIELD-EFFECT SEMICONDUCTOR DEVICE COMPRISING A BODY OF SEMICONDUCTOR MATERIAL HAVING A FIRST REGION OF ONE CONDUCTIVITY TYPE, A SECOND REGION OF THE OPPOSITE CONDUCTIVITY TYPE DISPOSED WITHIN SAID FIRST REGION AND EXTENDING INWARLY FROM THE SURFACE THEREOF AND FORMING A PN JUNCTION THEREWITH, A THIRD REGION OF SAID ONE CONDUCTIVITY TYPE, SAID THIRD REGION HAVING A SUBSTANTIALLY GREATER CONCENTRATION OF IMPURTIES AT SAID SURFACE OF SAID DEVICE THAT SAID SECOND REGION AND DISPOSED WITHIN SAID FIRST REGION LATERALLY EXTERNAL TO SAID SECOND REGION AND WITHIN SAID SECOND REGION, EXTENDING INWARDLY FROM SAID SURFACE, THE LATERAL DISPOSITION OF SAID THIRD REGION WITH RESPECT TO SAID SECOND REGION BEING SUCH TO LEAVE TWO PORTIONS OF THE SURFACE OF SAID SECOND REGION EXPOSED ON EACH OF TWO LATERALLY OPPOSITE SIDES OF SAID THIRD REGION, AT LEAST TWO OHMIC CONTACTS IN CONTACT WTH SAID SECOND REGION AT SAID TWO EXPOSED PORTIONS OF SAID SURFACE, ONE INDIVIDUAL TO EACH OF SAID LATERALLY OPPOSITE SIDES OF SAID THIRD REGION, AND AT LEAST ONE OHMIC CONTACT ATTACHED TO ONE OF THE REGIONS OF SAID ONE CONDUCTIVITY TYPE.