Aluminum in thin film seems to be migrating into dendrites
We observe a corrosion or stress migration phenomenon in 100 nm aluminum films on different kinds of substrates.
Optical inspection shows metal missing sites with dendritic form. Our assumption is that we have either a corrosion or stress problem in the films, but we cannot find any corrosion products.
Would be glad for any help with this!
Fraunhofer-Inst. for Solid State Technologie - Munich, Austria
You did not say if the missing metal/dendritic formation was present just after deposition of the Al film or over time. You also did not mention how the film was applied (wet or vac process).
It is possible that the dendritic formation is due to phase change as a result of impurities present in the original film /solid solution.
The missing metal areas may also indicate surface contamination which could result in lack of adhesion of the Al film.
You can send a sample out for analysis and have a layered ESCA percent assay performed to look for contaminants.
Good luck.Jeff Albom
- El Granada, California
June 20, 2009
Hi, Chris. Tin electroplating, and many other electroplatings have long been known to grow "whiskers" in a fashion that sounds very similar to what you are seeing in your aluminum thinfilm.
Some keys to fighting whisker growth are reducing the stress and alloying the metal with a small amount of something else so crystal growth is not quite so easy. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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