Diamond growth on hot-filament chemically vapour-deposited diamond for surface conductive device applications

Hydrogen-terminated diamond films are capable of displaying p-type character in the near-surface region. This effect can be used to fabricate surface unipolar electronic devices such as diodes and field effect transistors. However, the presence of contaminants within the diamond surface can reduce the carrier concentration and mobility values achieved within this layer to the point where devices can no longer be made. This paper reports on the formation of thin over-layers on relatively inexpensive contaminated ‘black’ polycrystalline diamond grown by hot-filament chemical vapour deposition. It has been found that such a layer is sufficient to enable sheet carrier concentrations approaching 1014 cm−2 to be generated, with mobility values greater than 20 cm2 V−1 s−1, comparable with values obtained on high-quality single crystals at these carrier concentrations. Effective Schottky diodes have been produced. [Copyright &y& Elsevier]