CORRELATION BETWEEN THE DENSITY OF TIO2 FILMS AND THEIR PROPERTIES

Stress, density and refractive index of approximate 100 nm thick titan ia films are determined for layers deposited on fused silica substrate s by reactive evaporation (RE), reactive ion plating (IP), plasma impu lse chemical vapour deposition (PICVD) and spin coating (SC). Relative densities (rho(film)/rho(ana)) vary between 0.7 and 1.0 with respect to the crystal phase uf anatase (rho(ana) = 3.84 g cm(-3)). The refrac tive index depends linearly on density. Film stress is tensile at low densities and compressive for layers with densities of the order or an atase. A strong correlation between stress and density is found to be independent from the deposition conditions and the crystal structure o f the as-deposited films. The phase transition from amorphous to anata se caused by annealing induces an increase in stress. The film density is correlated to the crystallization temperature. the size of stress increase during crystallization and the grain size.