1.3 COVALENT BONDING AND INTRINSIC MATERIALS
To fully appreciate why Si, Ge, and GaAs are the semiconductors of choice for the elec tronics industry requires some understanding of the atomic structure of each and how the atoms are bound together to form a crystalline structure. Every atom is composed of three basic particles: the electron, the proton, and the neutron. In the lattice structure, neutrons and protons form the nucleus and electrons appear in fixed orbits around the nucleus. The Bohr model for the three materials is provided in Fig. 1.3.