AMORPHOUS SOLID SYSTEMS - DIAMOND-LIKE CARBON, CARBIDES, FILMS AND MULTILAYER STRUCTURES

Diamond-like films (DLFs) may be considered as (1) a special kind of solid; (2) membranes with connected microscopic pores and (3) a matrix, the properties of which can be varied over a wide range by alloying. In W-Si alloyed DLFs all these structures are found, with resistances from 10(14) to 10(-4) OMEGA cm. They are interesting as examples of percolation phenomena and for their possible practical applications. The expected pore diameter has been estimated at about 0.30-0.35 nm and the pore density at 10(21) cm-3. However, scanning tunnelling microscopy gave evidence of negligible pore density and a metallic state in high tungsten films. Low angle electron and X-ray diffraction, scanning tunnelling microscopy, high voltage (1 MeV) transmission scanning electron microscopy (TSEM) and the analysis of the emissive picture of a W-edge coated with a DLF have demonstrated the presence of a uniform amorphous structure up to the equiatomic proportion C:W. A study has been made of the short-term and long-term temperature stability of DLFs and of their resistance to degradation and oxidation and of their chemical and mechanical durability.