PUB - Publikationen an der Universität Bielefeld

The deposition of diamond films in acetylene-oxygen flames with different amounts of acetone in the source gas was investigated. Diamond films were deposited on molybdenum at temperatures between 1070 and 1420 K using a welding torch. The temperature as well as the stoichiometry dependence of the growth rate and quality of the diamond films were examined. The concept of supersaturation was adapted in order to have an transferable measure of the equivalence ratio. A sharp change of the diamond morphology from {111} to {100} planes between 1320 and 1370 K and between 6 and 7% supersaturation was found. The growth rate as a function of time was measured for deposition times between 2.5 and 180 min. Acetone influences the optimal conditions of the diamond deposition, the growth rate and the quality of the films. This influence was investigated in two different experiments. First, the acetone/acetylene ratio was varied with fixed supersaturation, whereas, in the second series, the supersaturation was increased by adding acetone, with keeping the acetylene flow fixed. It was found that small amounts of acetone have a positive effect on the film quality and increase the growth rate. This result may be qualitatively understood by an increase of hydrogen atom and methyl radical concentrations upon acetone addition.