Optical anisotropy in thin films deposited obliquely: in situ 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),R( ||), T( perpendicular) and T( ||) as functions of mass thickness d. For both ZrO(2) and Ti(2)O(3), the experimental profile of (R( perpendicular) - R( ||)) 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.