Characterization of diamond films grown on amorphous SiO2

Abstract

Continuous diamond film growth on SiO2 was achieved by an effective pretreatment. Carbon implantation and diamond powder abrasion were used to enhance diamond nucleation on SiO2. The possibility of using two gas mixtures (CH4-CO2 and CH4-H-2) in order to achieve the growth of continuous diamond films on SiO2 was examined. The diamond film growth rate obtained using the CH4-CO2 gas mixture was 0.6 mu m/h which is roughly three times higher than that of the CH4-H-2 gas mixture. CH4-H-2 gas mixtures had a lower etching reaction rate than that of CH4-CO2 gas mixtures. The higher etching rate of the CH4-CO2 gas mixture was considered to be due to a higher concentration of active carbon radicals or carbon-containing species in the plasma. Scanning electron microscopy (SEM) and optical emission spectroscopy (OES) indicated that active carbon radicals and carbon-containing species are the major cause of pits arising at the surface. Using CH4-H-2 gas mixtures at a low microwave power gave the optimum reaction conditions for depositing diamond films on SiO2 layers.