LOW-TEMPERATURE ZIRCONIA THIN-FILM SYNTHESIS BY A CHEMICAL-VAPOR-DEPOSITION PROCESS INVOLVING ZRCL4 AND O-2-H-2-AR MICROWAVE POSTDISCHARGES- COMPARISON WITH A CONVENTIONAL CVD HYDROLYSIS PROCESS

Thin films of zirconia have been deposited at 733 K and below by micro wave post-discharge-assisted oxidation of ZrCl4 in O-2-H-2-Ar mixtures , leading to monoclinic layers with a columnar morphology. The highest deposition rates were obtained when both H-2 and O-2 passed through t he discharge, with a flowrate ratio of H-2/O-2 = 2. The results have b een compared with those for a conventional chemical vapour deposition (CVD) process based on the hydrolysis of ZrCl4. Together with informat ion gained on the post-discharge process using other investigation met hods, such as mass spectrometry and measurements of atomic oxygen conc entrations by NO titration, they have helped to shed light on the reac tion paths. The mechanism leading to zirconia formation has been ident ified as being a simple hydrolysis reaction in the late post-discharge . The microwave post-discharge-assisted O-2-H-2-Ar process thus seems to behave like a conventional CVD technique in the temperature range f rom 573 to 733 K.