Synthesis of microstructure diamond and related materials at different CH4 /H2 in the reactant gases

Diamond structure were deposited on gold coated Si substrate successfully using DC-PECVD technique at different CH4 /H2 in the reactant gases (CH4/H2 = 2, 5 and 7 vol. %). Characterization of diamond structure has been investigated in detail by X-ray diffraction (XRD), Raman spectroscopy (RS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results determined the effect of the different CH4 /H2 in the reactant gases on the crystallinity, phase, surface morphology and microstructure. The XRD patterns showed polycrystalline structure with diamond (111) preferred growth orientation and better crystalline quality at middle methane concentrations. The first order Raman peak for diamond phase was more intense at middle methane concentrations, while a relatively broad G-band from the graphitic species was appearance. Diamond structures with large grain sizes in the micron or tens of micron range have homogenous surface.