Solid State Electronic Devices, 7th Edition

5.1 Fabrication of p-n Junctions

Although this book deals primarily with how devices work rather than how they are made, it is instructive to have an overview of the fabrication process in order to appreciate device physics. We have already discussed in Chapter  1 how single-crystal substrates and epitaxial layers needed for high-quality devices are grown, and how the doping can be varied as a function of depth. However, we have not discussed how doping can be varied laterally across the surface, which is key to making integrated circuits on a wafer. Hence, it is necessary to be able to form patterned masks on the wafer corresponding to the circuitry, and introduce the dopants selectively through windows in the mask. We will first briefly describe ...