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2008
Conference Paper
Titel
All-optical in-situ analysis of PIAD deposition processes
Abstract
In the case of plasma ion assisted deposition (PIAD) processes either quartz crystal monitoring or optical monitoring are commonly applied to control thickness of the layers. For several oxide layer materials the final stoichiometry of the deposited film is extremely sensitive to the oxygen gas inlet during the deposition process. It is well known, that under these circumstances, variations in the reaction gas flow or in deposition rates may cause unwanted variations of the stoichiometry of the coating. Finally this results in film inhomogeneities and increased absorption losses, which cannot be identified early enough and reliably by in-situ transmission spectroscopy alone. For this reason, the correlation between optical performance of the coating and emission spectra of the APS-plasma measured by a separate analyzer has been investigated. The synchronization in recording in-situ transmission spectra and plasma emission spectra was achieved by developing a common trigger unit for both spectrum analyzers. From the correlation between spectrophotometry and emission spectroscopy, we expect an earlier and more reliable assignment of absorption losses and inhomogeneities to instabilities in the process parameters of the deposition process.