Structural state and mechanical properties of nanocrystalline carbon films obtained by methane pyrolysis in electric field

We describe a method of carbon film synthesis on single-crystalline silicon substrate, which is based on methane pyrolysis in electric field. The calculated values of pressures and temperatures developed during the bombardment of substrates by C$^{-4}$ carbon ions in the course of pyrolysis amount to $P\sim$ 1.3 GPa and $T\sim$ 2300 K, respectively. These conditions lead to the formation of nucleation centers that are necessary for the growth of carbon film. Measurements show that the microhardness of obtained carbon films reaches 60–80% of the hardness of natural diamond. The structural state of the film material was studied by X-ray diffraction, electron microscopy, and atomic force microscopy. It is established that the synthesized films represent a composite material with a carbon matrix containing nanodimensional inclusions of another phase.