Hi friends,
Recently we have deposited a multilayer stack using materials like TiO2, HfO2 combination and TiO2, Y2O3 combination.
both combination of stacks were deposited by electron beam evaporation technique at 200 degrees centigrade.
what is the reason behind this....how the grain growth effects the coated film in the case of TiO2/Y2O3 combination.
Does the Temperature of the coating is plays a role in the stress generation in the above material combination?
I don't understand the real question ask but if you are depositing on a glass substrate you need to give the substrate thorough cleaning treatment using nitrate reagent for secs and then rinse in distilled water and air dry,
There are a number of issues - adhesion as noted by Ismail above, differences in thermal expansion (substrate versus coating), film density (greater density typically moves the stress to a more compressive state, lower density moves to a more tensile state), relative humidity of the use environment, etc. By looking at how the coating fails (compressive - bubbles up in a convex manner, tensile, cracks and curls in a concave manner), you can better understand the issue. Depending on the failure mechanism, you may need to change the film density to make it compatible with the substrate and environment.
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