The objective of the proposed program is to develop a prototype of a novel large area, thin film, microwave diamond deposition reactor. Present microwave reactors for the deposition of thin diamond and diamond-like films from the gas phase are limited to small diameters, typically 2-3". The possibility of achieving larger area thin films would open new possibilities for these coatings which possess unique corrosion, chemical, electrical, optical and hardness properties. There are direct commercial applications for such films in a variety of markets. The proposed reactor design exploits the physics of microwave plasma formation to generate a spatially uniform flux of chemically excited process gas to the substrate on which the thin film is grown. In order to attain this uniform flow, however, neutral gas fluid flows, plasma generation and microwave coupling must be carefully modeled in order to provide design tools with which to refine initial proof of principle prototypes. In Phase I these modeling tools would be developed and a prototype design working drawings created. In Phase II, the prototype would be built and optimized.