OPTICAL ANISOTROPY IN THIN-FILMS DEPOSITED OBLIQUELY - INSITU OBSERVATIONS AND COMPUTER MODELING

Normal incidence optical anisotropies are monitored during the growth of dielectric and metal films deposited at 45-degrees by logging the quantities R perpendicular-to, R parallel-to, T perpendicular-to and T parallel-to as functions of mass thickness d. For both ZrO2 and Ti2O3, the experimental profile of (R perpendicular-to - R parallel-to) vs d is consistent with a refractive anisotropy that remains nearly constant during deposition. Gold, silver, and aluminum (deposited in the absence of oxygen) are shown to exhibit characteristic anisotropy vs d profiles that can be associated with the refractive index resonance in a globular metal film. The anisotropic effects observed in metals, both during deposition and during subsequent argon-ion sputter etching, are modeled by considering the film to comprise a mixture of crystallite- and void-defined materials and by adopting simplified structural hysteresis loops.