Simultaneous fabrication of nanocrystalline and {100} textured large-grained diamond films

In this work, we report the simultaneous synthesis of both nanocrystalline and {100} textured large-grained diamond films in one deposition run performed in a 5-kW microwave plasma chemical vapor deposition (MPCVD) reactor. This was achieved by employing the coupled effect of nitrogen addition in the gas phase and substrate temperature on the growth of diamond films. In one deposition run, different substrate surface temperatures were obtained by a novel substrate arrangement, nanocrystalline diamond of high growth rate around 3 μm/h was formed at low temperature, while {100} textured large-grained diamond of much higher growth rate about 11 μm/h was grown at high temperature. This new method opens way for mechanical and tribological applications of both nano-diamond and {100} textured diamond in industrial level. This result indicates that distinct growth modes or growth mechanisms were involved at different substrate temperatures with a certain amount of nitrogen addition. The coupled effect of nitrogen addition and temperature on the growth of CVD diamond films and the involved growth mechanism is briefly discussed from the point of view of gas phase chemistry and surface reactions.