ABSTRACT
In the previous chapters, we discussed the properties of semiconductors and their defects. Doping, the controlled introduction of impurities into well-defined areas of a semiconductor, exploits these properties to produce useful devices. In this chapter, several methods of introducing dopants into semiconductors are summarized. These methods can be grouped into two broad categories, doping during and after crystal growth. After reviewing the basics of bulk crystal growth and doping, we describe several thin-film growth techniques. In addition to introducing precise concentrations of dopants, unwanted contaminants must be minimized. The degree of perfection of a single crystal depends on the purity of the starting materials and on the particular technique used to grow the crystal. Postgrowth doping methods include diffusion, ion implantation, and neutron transmutation. Along with doping, we discuss annealing, a thermal processing step that is often required to repair crystal damage and electrically activate the dopants.
