Plasma polymer films at nanoscale view

conference paper

English

Plasma polymer films of vinyltriethoxysilane prepared at the same deposition conditions but different film thickness were analyzed with respect to mechanical and optical properties, and surface morphology. A Nano Indenter XP (MTS Systems Co.) was used to carry out the indentation tests and the depth profile of the elastic modulus and hardness to 20% of the film thickness was evaluated. A phase-modulated spectroscopic ellipsometer UVISEL (Jobin-Yvon) was used to characterize optical constants of films in the spectral range 240 - 830 nm. A model of a single homogeneous film on the semi-infinite silicon substrate was used for the calculation of the film thickness, refractive index and extinction coefficient. Surface morphology of films was observed by atomic force microscope, AFM (Accurex IIL, Topometrix) and the RMS roughness was determined. Plasma polymer films of the thickness ranging from 16 to 4145 nm were deposited on silicon wafers. The mean deposition rate decreased from 190 to 52 nm min-1 and the RMS roughness increased from 0.1 to 7.0 nm when the film thickness enlarged (Fig. 1). An increased value of the refractive index and extinction coefficient was observed in the ultraviolet region for thicker films. A magnitude of the elastic modulus was dependent on the film thickness for ultrathin films and this phenomenon could evidence about a film growth influenced by the substrate. A surface layer of lower modulus and enlarging with the film thickness was detected at thicker films. The results are very important for construction of functional interlayers applied in multi-component materials.

plasma polymer; nanoindentation; AFM

ČECH, V., VANĚK, J., DRZAL, L., XU, L.

2005

1. 8. 2005

Veeco

Santa Barbara, USA

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