Metallorganic chemical vapor deposition of Ta2O5 films

Ta2O5 films were grown by pulsed-metal organic chemical vapour deposition (pulsed-MOCVD) which utilises direct liquid injection of a precursor solution using an ultrasonic nozzle to introduce the precursor vapour into a low-pressure vertical cold-wall reactor. Tantalum (V) ethoxide (C10H25O5Ta) was chosen as an oxygen-containing precursor with low decomposition temperature. Films were grown in the temperature range 400-800 C. Three solution concentrations were tested (1, 2 and 4 vol%) and the growth rate controlling mechanism and film quality were analysed. The highest growth rate was achieved with the most dilute solution and a film thickness of 3 micron was achieved with a growing rate of 8.52 micron/h. The refractive index and dielectric constant of the films increased with an increase in temperature, and the 1 vol% solution led to the best growing rate. The morphology and porosity of the films could be controlled by deposition temperature and solution concentration. Pulsed-MOCVD provided uniform film thickness and high growth rate. 18 refs.