1.1.5 Oxidation

A highly relevant reason why silicon has become such an important material in the microelectronics industry and IC fabrication is the relative ease with which it can be oxidized to form silicon dioxide (SiO$_2$) with good material properties. This process relies on providing an oxidant species (O$_2$ or H$_2$O), which reacts with the silicon atoms to grow silicon dioxide at high temperatures. The thermal oxidation process can be divided into two main mechanisms: dry oxidation, where the silicon wafer is placed in an oxygen gas ambient and wet oxidation, where the silicon wafer is placed in a water ambient. However, silicon dioxide can also be deposited, which is the case, when it must be grown on non-silicon surfaces. This type of deposition is usually performed using TEOS or silane pyrolysis. The oxidation process is discussed in more detail in Chapter 2.