The electrical properties and device applications of homoepitaxial and polycrystalline diamond films

For years diamond has been known as a promising material for several types of semiconductor devices. Many of these applications are in the area of high-temperature and high-power electronics. There is presently a renewed interest in electronic applications of semiconductor diamond stemming from the development of the activated chemical vapor deposition (CVD) processes for the growth of thin diamond films. The scope of this research project is to determine the feasibility of thin-film diamond for electronic applications.;The diamond-film growth method used throughout this work is microwave plasma assisted chemical vapor deposition. The films that were grown on silicon substrates were polycrystalline in form, while single-crystal films were grown epitaxially on natural diamond substrates.;The main focus of this thesis is the fabrication of experimental thin-film diamond semiconductor devices. The work in this area was initiated by Penn State's research group in 1987 with the fabrication of the first semiconductor device (a Schottky diode) based on CVD diamond. Fabrication of more complex structures required the development of new semiconductor processing techniques. These included the formation of ohmic contacts, surface preparation and cleaning of the films, selective area growth of diamond, and plasma etching of epitaxial diamond films, among others. Some of the film properties that were investigated include resistivity, carrier type, concentration and mobility, thermal activation energy of the resistivity, Schottky barrier height, and optical absorption. The study of the electrical properties was used to adjust the growth parameters of the films in a way that made possible the fabrication of Schottky diodes and field-effect transistors. The high-temperature operation of these devices (up to 580;The experimental data in this thesis were confirmed by similar studies performed by other research groups. The results obtained by these groups are presented in order to provide a complete review of the status of semiconductor diamond technology. The emphasis is on the areas of current research activity and electronic device development. The promising areas for future research are discussed in the concluding chapter.