Ellipsometric Determination of Properties of Films on Rough Surfaces Such as Aluminum Alloy Aircraft Skin.
Interim rept. 1 Jan 76-1 Aug 77,
TEXAS TECH UNIV LUBBOCK OPTICAL SCIENCES LAB
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The properties of oxide layers on smooth and rough aluminum surfaces are considered in this study. Using ellipsometric techniques, the layer thickness and the four parameters describing the complex indices of refraction for film and substrate are assigned effective values and interrelations are deduced. The organizing feature of the work is the use of data trajectories generated by determining the ellipsometric parameters Psi and Delta over and over for samples that were heated between measurements. The heating caused increases in the oxide layer thickness, so that the data trajectories could be used along side theoretical thickness curves to determine appropriate effective media parameters. One of the more interesting results was the representation of rolling grain marks on alclad by an effective complex index of refraction. The effective index determined was dependent on the sample orientation. Author
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