Effect of the substrate state on the formation of diamond film in a low temperature microwave-plasma-enhanced chemical vapor deposition system

Abstract

Diamond films were deposited on substrates using a low temperature microwave-plasma-enhanced chemical vapor deposition system. Low temperature (below 500 °C) deposition can be achieved only by making the substrate position remote from the plasma under the normal deposition condition. The substrate was untreated or was pre-treated by 30 μm diamond powder. Among various substrates (untreated silicon, pre-treated silicon, pre-treated quartz, untreated glass, and pre-treated glass), pre-treated quartz and pre-treated glass enhance the diamond formation, while untreated glass gives only graphite formation even under the same deposition conditions. We understand that the better formation of diamond on pre-treated glass and pre-treated quartz was due to the existence of a diamond particle on the substrates. We also deposited diamond films on pre-treated glass at various CH4 concentrations. The largest grain size can be acquired at 3% of CH4 concentration and the growth rate of the film increases with increasing CH4 concentration.