Thin films formed by Plasma Enhanced Chemical Vapor Deposition (PECVD) are used in a many important products and industries including: integrated circuits, flat panel displays and related thin film transistor technologies, as hard carbon coatings, and as magnetic and superconducting materials. Models of the deposition process: how it is influenced by reactor design and operating regime, are needed to streamline reactor design and operation. Useful models must relate the macroscopic film properties such as growth rate, uniformity, and composition to variations in reactor design and operation. Innovative models are necessary to regain the lead in PECVD equipment manufacturing and deposition technology from the Japanese. In Phase I, a framework will be established to guide the formulation of commercially useful models. The general PECVD process will be viewed as a culmination of 6 subprocesses: gas flow, heat flow, thermodynamics, plasma energy distribution, plasma induced reactions, and surface reactions. A lumped parameter analysis of PECVD will be developed to determine which subprocesses dominate any specific deposition technology. In addition, the important plasma sources: parallel plate electrodes, ECR sources, and triode reactor configurations, will be modeled in one- and two-dimensions . Finally, the lumped parameter model will be used to analyze the deposition of amorphous silicon and hard carbon coatings. Anticipated benefits/potential commercial applications - among the benefits are an improved understanding of PECVD and a formal structure (the lumped parameter model) with which to compare reactor designs and deposition technologies. Anticipated commercial products include models to facilitate the design of plasma sources and reactors. Software packages will be developed to simplify machine operation and minimize the amount of characterization required in