Polycrystalline diamond synthesis by means of high power pulsed plasma glow discharge CVD

A pulsed glow discharge reactor for chemical vapour deposition of high quality diamond films is presented. The Raman quality and the morphology of the diamond films exhibit a strong dependence on the discharge pulse shape. This result is explained with a simple model involving the average current density j0 and the average squared amplitude of the pulse left angle bracketΔj2right-pointing angle bracket as relevant parameters. This CVD method does not require any substrate pretreatment, and the nucleation rate is seen to increase with current density, methane concentration and pressure. The quality of the deposits is independent of the inter-electrode distance in the 25–35 mm range. The influence of the substrate temperature on the diamond morphology and on diamond etching from the substrate is discussed.