TABLE OF CONTENTS The ability of a silicon surface to form a silicon dioxide passivation layer is one of the key factors in silicon technology. In this chapter, the uses, formation, and processes of silicon dioxide growth are explained. Detailed is the all-important tube furnace, which is a mainstay of oxidation, diffusion, heat treatment, and chemical vapor deposition processes. Other oxidation methods, including rapid thermal processing, are also explained.
Upon completion of this chapter, you should be able to:
List the three principal uses of a silicon dioxide layer in silicon devices.
Describe the mechanism of thermal oxidation.
Sketch and identify the principal sections of a tube furnace.
List the two oxidants used in thermal oxidation.
Sketch a diagram of a dryox oxidation system.
Draw a flow diagram of a typical oxidation process.
Explain the relationship of process time, pressure, and temperature on the thickness of a thermally grown silicon dioxide layer.
Describe the principles and uses of rapid thermal, high-pressure, and anodic oxidation.
Of all the advantages of silicon for the formation of semiconductor devices, the ease of growing a silicon dioxide layer is perhaps the most useful. Whenever a silicon surface is exposed to oxygen, it is converted to silicon dioxide (Fig. 7.1). Silicon dioxide is composed of one silicon atom and two oxygen atoms (SiO 2). We encounter silicon dioxide daily. It is the chemical composition of ordinary window glass. It s semiconductor version, however, is...
