Operation and electrical characteristics of the bipolar transistor
Integrated Bipolar Transistors Silicon Germanium BiCMOS Technologies

The operation of the component is apprehended using a homojunction NPN bipolar transistor, i.e. made of a single material such as silicon. This active component is made up of two head-to-tail PN junctions, each made up of three main regions successively doped N⁺, P and N. These regions are called emitter, base and collector respectively. In this paragraph, we give the operating principles for an NPN transistor in a forward operating mode, i.e. when the emitter-base junction (E-B) is forward biased (V_BE > 0 V), while the base-collector junction (B-C) is reverse biased (V_BC < 0 V). These polarizations will modulate the two space charge zones (SCZs) (also known as depletion zones) thus created, and determine the mode and amplitude of charge...