Ivan Ohlídal, Miroslav Ohlídal, Daniel Franta, Vladimír Čudek, Vilma Buršíková, Petr Klapetek, Miloš Jákl

Proc: Optical measurement of mechanical stresses in diamond-like carbon films

Proceedings of 8-th International Symposium on Laser Metrology, SPIE (2005) pp.717-728

Published by SPIE – The International Society for Optical Engineering, Bellingham, Washington, USA

In this paper the mechanical stresses taking place in diamond like thin films prepared by the plasma enhanced chemical vapor deposition onto silicon single crystal substrates are studied. For determination of the stress values the Stoney's formula is used. The values of the film thicknesses are determined using the combined method of variable angle spectroscopic ellipsometry and near-normal spectroscopic reflectometry. The values of the curvature radii of the deformed silicon substrates in consequence of the film stresses are evaluated using interferometric method based on two-beam interferometry and chromatic aberration method. The dependence of the mechanical stress inside these films on their thickness values is determined. It is found that this dependence can be approximate by the straight-line. The results achieved for the mechanical stresses obtained by both the optical methods, i.e. by the interferometric and chromatic aberration method, are compared. It is shown that within the experimental accuracy the stress values determined using both these method are identical. Thus, it is shown that the chromatic aberration method is suitable for measuring the mechanical stresses inside the thin solid films and it is the competitive method for the other optical methods utilized for this purpose so far.

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You may also contact one of the authors: ohlidal@physics.muni.cz, franta@physics.muni.cz, vilmab@physics.muni.cz

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