The increasing importance of high temperature electronics has necessitated a search for new materials. Silicon provides low reliability or fails to function altogether at elevated (>500F /260(C) temperatures. Diamond, being a wide-band-gap semiconductor, is a very promising candidate for these applications as well as others that function in adverse conditions. However, the present day diamond film technology, with respect to quality and consistency of properties of the films, has not seen the advancement required for its commercial application. This research is an effort to investigate the growth of diamond thin films to enable their application for advanced electronic devices. The first objective of the research was to construct a state of the art Electron Cyclotron Resonance Microwave Plasma Chemical Vapor Deposition (ECR-MPCVD) system for processing diamond and diamond like materials. Such a facility is the most advanced and powerful tool for CVD of poly-crystalline diamond and cubic Boron Nitride. Important factors like ease of operation and maintenance, stability and reproducibility of process conditions, reliability, safety, cost etc were considered while constructing the machine. The system was subjected to a series of tests to ensure that these factors were adequately satisfied. The second objective of this project was to grow polycrystalline diamond films under various conditions of chamber pressure, substrate temperature, hydrogen flow rate, composition and substrate pretreatment. The properties of the films grown under these conditions were evaluated by various modern characterization techniques such as optical microscopy, scanning electron microscopy, Raman spectroscopy and X-ray diffraction. Optical microscopy is an inexpensive, quick and effective method for initial evaluation of the uniformity and general morphology of the films obtained. Scanning electron microscopy gives information about the grain size, thickness, growth rate, uniformity, faceting, roughness, and continuous nature of the film. Raman spectroscopy is probably the most important characterization method for diamond films for electronic applications. It helps to identify the presence of diamond and the nature of the film. Raman spectrum is used to evaluate the quality of the diamond grains in the film, defect concentration and crystallinity. It also gives information about the presence of the non-diamond graphite phase and hence indirectly the intrinsic conductivity. XRD is also a positive identification tool. It was also used to derive information about the grain orientation with respect to the silicon substrate. The properties of the films obtained were correlated with the growth parameters and conclusions were drawn about the effect of these parameters on the film properties. This also helped in the characterization of the MPCVD reactor and in determining an effective range of parameters for future studies on the selective growth, long term growth, or growth of films with oxygen addition to the precursor. These efforts would be stepping stones for future studies by the group in this field of research. Based on these efforts, a versatile ECR plasma CVD system has been designed and created. High quality polycrystalline diamond films were prepared in a methane-hydrogen plasma environment and characterized. It was demonstrated that the morphology and crystallinity of the diamond deposit could be controlled by changing the growth parameters.