Morphology of electrochemical vapor deposited yttria-stabilized zirconia thin films

Yttria-stabilized zirconia films were deposited over alumina substrates by electrochemical vapor deposition (EVD). It was observed that the films grew with the same yttrium-to-zircomium ratio as in the reactant gases. Films deposited at temperatures of 1075°C or below have a highly faceted surface and show a preferred crystallographic orientation. Films deposited at a temperature of 1100°C show a nearly smooth surface and no crystallographic orientation. The difference in morphology between the high temperature and lower temperature films can be explained by either a change in the relative rates of film growth and surface reconstruction or, more likely, a mobile surface species becoming thermodynamically unstable at the higher temperature.