Page 28 - Semiconductor For Micro- and Nanotechnology An Introduction For Engineers

Chapter 2 The Crystal
Lattice System

In this chapter we start our study of the semiconductor system with the
(
crystals of silicon Si) , adding some detail on crystalline silicon dioxide
( SiO ) and to a lesser extent on gallium arsenide GaAs) . All three are
(
2
regular lattice-arrangements of atoms or atoms. For the semiconductors
silicon and gallium arsenide, we will consider a model that completely
de-couple the behavior of the atoms from the valence electrons, assuming
that electronic dynamics can be considered as a perturbation to the lattice
dynamics, a topic dealt with in Chapter 3. For all the electrons of the
ionic crystal silicon dioxide, as well as the bound electrons of the semi-
conductors, we here assume that they obediently follow the motion of the
atoms.

We will see that by applying the methods of classical, statistical and
quantum mechanics to the lattice, we are able to predict a number of
observable constitutive phenomena of interest—i.e., we are able to
explain macroscopic measurements in terms of microscopic crystal lat-
tice mechanics. The effects include an approximation for the elastic coef-

Semiconductors for Micro and Nanosystem Technology 27