Development of a plate-to-plate MPCVD reactor configuration for diamond synthesis

•A novel MPCVD reactor with dual substrates configuration is described.•The polycrystalline or single-crystal diamond can be grown on the dual substrates.•The reactor's plasma absorbed power density and operation pressure regime increased.

The design and performance of a microwave plasma chemical vapor deposition (MPCVD) reactor based on compressed microwave waveguides and plate-to-plate substrate holders are described. This reactor can be operated at pressures from 10 to 40 kPa with microwave power of 0.4–1.2 kW, and a high plasma power density up to 500 W/cm3 can be obtained. The single-crystal diamond (lower substrate holder) and polycrystalline diamond (upper substrate holder) have been grown by the plate-to-plate MPCVD reactor using high pressure CH4-H2 mixture gases. Experimental results show that high quality single-crystal diamond and polycrystalline diamond were simultaneously synthesized at a growth rate of 25 μm/h and 12 μm/h, respectively. The results indicate that our MPCVD reactor is unique for the synthesis of diamond with high efficiency.

Graphical abstractA novel MPCVD reactor with a plate-to-plate substrate holders configuration has been developed which is first reported in the paper. The major designs were the rectangle compression waveguide in microwave plasma cavity reactor and the novel plate-to-plate substrate holders. The specific plate-to-plate configuration makes the high quality polycrystalline and single crystal diamonds can be simultaneously grown on both substrates. Such developments are significant not only for the optimization of MPCVD reactor but also for the diamond industry.Figure optionsDownload full-size imageDownload as PowerPoint slide