Layered thin-film structures are used in microelectronic, opto-electronic, flat panel display, and electronic packaging technologies. A few examples are given below. Very large-scale integration (VLSI) of circuits on computer chips are made of multilayers of interconnects of thin metal films patterned into submicron-wide lines and vias. Semiconductor transistor devices rely on the growth of epitaxial thin layers on semiconductor substrates, such as the growth of a thin layer of p-type Si on a substrate of n+-type Si [1–3]. The gate of the transistor device is formed by the growth of a thin layer of oxide on the semiconductor. Solid-state lasers are made by sandwiching thin layers of light-emitting semiconductors between layers of a different semiconductor. In electronic and optical systems, the active device elements lie within the top few microns of the surface; this is the province of thin-film technology. Thin films bridge the gap between monolayer (or nanoscale structures) and bulk structures. They span thicknesses ranging from a few nanometers to a few microns. This book deals with the science of processing and reliability of thin films as they apply to electronic technology and devices . To begin, this chapter describes the application of thin films to modern advanced technologies with examples.