Integral transistor pair for use as chopper

Claim 1

A DUAL-EMITTER TRANSISTOR DEVICE FOR USE IN A TRANSISTOR SWITCH COMPRISING: (A) A WAFER OF SINGLE-CRYSTAL SEMICONDUCTOR MATERIAL, THE WAFER BEING PREDOMINANTLY OF ONE CONDUCTIVITYTYPE AND PROVIDING A COMMON COLLECTOR REGION, (B) A FIRST REGION OF THE WAFER PROVIDING A COMMON BASE REGION, SAID FIRST REGION BEING OF THE OPPOSITE CONDUCTIVITY-TYPE AND BEING LOCATED ADJACENT A MAJOR FACE OF THE WAFER AND CONTIGUOUS TO THE MATERIAL OF SAID ONE CONDUCTIVITY-TYPE, THE INTERFACE BETWEEN THE FIRST REGION AND THE BULK OF THE WAFER BEING A P-N JUNCTION A MAJOR PORTION OF WHICH IS SUBSTANTIALLY PARALLEL TO THE MAJOR FACE, THE REGION BEING SYMMETRICAL ABOUT A CENTRAL AXIS, (C) A SECOND AND A THIRD REGION OF THE WAFER OF SAID ONE CONDUCTIVITY-TYPE BEING SUBSTANTIALLY EQUAL IN AREA AND ADJACENT THE MAJOR FACE AND CONTIGUOUS TO THE FIRST REGION SO AS TO PROVIDE THE EMITTERS OF THE DEVICE, THE SECOND AND THIRD REGIONS BEING SPACED FROM THE COLLECTOR REGION AND LATERALLY SPACED FROM ONE ANOTHER IN A MANNER SYMMETRICAL ABOUT SAID CENTRAL AXIS, (D) A COLLECTOR CONTACT TO THE WAFER ON A FACE OPPOSITE SAID MAJOR FACE UNIFORMLY SPACED FROM THE FIRST REGION, (E) A SINGLE RING-LIKE BASE CONTACT OHMICALLY ENGAGING THE FIRST REGION, SAID BASE CONTACT SUBSTANTIALLY ENCLOSING THE SECOND AND THIRD REGIONS AND BEING SUBSTANTIALLY EQUAL SPACED THEREFROM AND SYMMETRICAL ABOUT SAID CENTRAL AXIS, (F) AND A PAIR OF EMITTER CONTACTS TO THE WAFER ENGAGING THE SECOND AND THIRD REGIONS, RESPECTIVELY, AND SYMMETRICAL SPACED FROM THE BASE CONTACT.