Growth from the Vapor

Abstract

Growth from the vapor for preparing materials, particularly in the form of thin films, has become an extremely important technique. Probably the best example is its extensive use in the fabrication of silicon semiconductor devices and integrated circuits. Chemical vapor deposition is used to prepare the high-purity polycrystalline silicon, which is then melt-grown into single crystals. Thin silicon films, in which the actual devices and circuits are formed, are grown on slices of these crystals by chemical vapor deposition. Thin layers of silicon dioxide and silicon nitride are vapor-deposited for insulation and surface passivation. Finally, metal interconnect patterns are deposited, generally by vacuum evaporation. Chemical vapor deposition is also used for preparing high-purity metals, such as titanium, zirconium, hafnium, thorium, and chromium, and for a wide variety of other materials. Vacuum evaporation is used for depositing thin layers of many materials for surface coatings. The important present and potential uses of vapor deposition have spurred extensive research on these processes during the past decade. This chapter will discuss the general principles of growth from the vapor. Particular emphasis will be placed on the relative contributions of thermodynamic and kinetic factors to vapor deposition processes. Application of these principles will be illustrated using vapor-phase epitaxial growth as an example.