Combined in situ FTIR-spectroscopic and electrochemical analysis of nanopores in ultra-thin SiOx-like plasma polymer barrier films
C-N Liu, B Ozkaya, S Steves, Peter Awakowicz, G Grundmeier
JOURNAL OF PHYSICS D-APPLIED PHYSICS, Volume: 46, Issue: 8, Article Number: 084015, DOI: 10.1088/0022-3727/46/8/084015, Published: FEB 27 2013
Plasma polymerized SiOx barrier films were investigated by means of in situ spectroscopic and electrochemical methods to correlate the process parameters such as applied substrate bias with the resulting barrier properties. SiOx layers with various hexamethyldisiloxane/oxygen ratio were deposited with and without applied substrate bias. The resulting film morphologies were characterized by means of atomic force microscopy, and the presence of nanopores was analysed by cyclic voltammetry. In order to compare the film density and the presence of nanopore structure, evaluation of interfacial hydroxyl groups was performed by means of discrete polarization modulation Fourier transform infrared reflection-absorption spectroscopy in atmospheres with controlled partial pressures of H2O or D2O. It could be shown that the electrochemical and in situ spectroscopic approach allows for the analysis of nanopores and that a clear correlation of process parameters and film structure can be established.