Effect of precursor stoichiometry on morphology, phase purity, and texture formation of hot filament CVD diamond films grown on Si (100) substrate

The effect of precursor stoichiometry is reported on morphology, phase purity, and texture formation of polycrystalline diamond films. The diamond films were deposited on 100-mm Si (100) substrates using hot filament chemical vapor deposition at substrate temperature 720-750 degrees C using a mixture of methane and hydrogen. The gas mixture was varied with methane concentrations 1.5% to 4.5%. Diamond film thickness and average grain size both increase with increasing methane concentration. Diamond quality was checked using surface and cross-section by ultraviolet micro-Raman spectroscopy. The data show consistent diamond properties across the surface of the film and along the cross-section. XRD pole figure analyses of the films show that 3.0% methane results in preferential orientation of diamond in the < 111 & rang; direction, whereas films deposited with 4.5% methane showed texture along the < 220 & rang; direction in addition to < 111 & rang; which was tilted - 23 degrees with respect to the surface normal.