Optical anisotropy of tilted columns thin films of chromium deposited at oblique incidence

Several chromium thin films with thicknesses comprised between 840 nm and 440 nm have been deposited by magnetron sputtering at glancing angle on silicon substrates. The deposition angle was varied between 0° and 80° resulting in nanosculptured thin films with column angles comprised between 0° and 25°. The surface topography of the films has been characterized by atomic force microscopy. It revealed different structurations of the surface originating from: the cross-section of the tilted columns with the surface, lateral ordering of the columns and faceting. The optical properties of the films have been determined from generalized ellipsometric measurements performed along different azimuths. The inspection of the off-diagonal elements of the Jones matrix as a function of columns tilt angle showed that both in-plane and out-of-plane anisotropy were present, associated with the columnar growth.