Sr John Steven

Analogue and Digital Electronics Sr John Steven

The pn junction forms the basis of a large number of semiconductor devices. A BJT is formed by joining three sections of semiconductor material, each with a different doping concentration. The three sections can be either a thin nregion sandwiched between p] and p layers, or a p region between n and n+ layers, where the superscript "plus" indicates more heavily doped material. The resulting BJTs are called pnp and npn transistors, respectively.