A Ellipsometric Study of the Anisotropic Optical Properties of Thin Copper-Oxide Films.

The ellipsometric measurements of both thin (average thickness 1263.8 A) copper oxide films and ultra thin (30-50 A) copper oxide films on the (110) face of a copper single crystal confirmed the anisotropic behavior reported by Cathcart and Petersen. The thin film optical indices of the copper oxide were found to be 2.7557, 2.7709, and 2.7020 which agreed with the magnitudes expected for strain induced anisotropy. The ultra thin film measurements at a single angle of incidence could be explained by a variety of copper oxide indices by changing the film thickness. For the ultra thin film case, the variation in the ellipsometric measurements could not be explained by a tensor theory and it appears that some non-linear terms are required to relate the change in optical constants to the strain.