Transistor with a predetermined current gain in a bipolar integrated

Abstract

A bipolar integrated circuit with N-type wells (2) formed in a P-type substrate (1) includes in first wells, first transistors (EBC), the well of which constitutes the collector. P-type base region (7a) is formed in the first well with an N+ emitter region (8) formed in the base region. In at least a second well forming a collector, a composite second transistor (E'B'C') is constituted by an elemental third transistor (E.sub.1 B.sub.1 C') comprising regions of the same doping level as the first transistor and an elemental fourth transistor (E.sub.2 B.sub.2 C') having a base region (11) with a high doping level with respect to that of the bases of the first transistor. Emitter regions (8b, 12) of the elemental transistors are of the same doping level as that of the first transistors. The emitters and bases of the third and fourth elementary transistors are interconnected and constitute the emitter and the base of the composite second transistor.