Growth mechanisms of silicon oxide nano-layers grown onto polymeric substrates for flexible electronics applications

Silicon oxide (SiOx) thin films are used as protective layers on flexible electronic devices in order to protect them from permeation of atmospheric O-2 and H2O that induce corrosion effects to the active layers of these devices. In this work in-situ and real-time Spectroscopic Ellipsometry (SE) was used to monitor the SiOx deposition onto the polymeric substrates. The analysis of the real-time SE measurements revealed information about the growth mechanism and showed that SiOx follows an island type growth mechanism onto Poly(Ethylene Terephthalate)-PET substrate and a layer-by-layer mechanism onto Poly(Ethylene Naphthalate)-PEN substrate. Also, SE provides information about the evolution of the optical response during the deposition of SiOx. nano-layers and of SiOx stoichiometry and how it is affected by substrate's surface. Furthermore the realization of sequential SE measurements onto different sites onto the sample surface led to the spatial distribution of the SiOx nano-layers optical properties. Finally the investigation of SiOx bonding structure has been performed by Fourier Transform InfraRed Spectroscopic Ellipsometry (FTIRSE) and led to the determination of the different vibrational modes of SiOx nano-layers and its relation to the SiOx growth mechanisms and the substrates (PET and PEN). (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.