Refractive-index dispersion of phosphosilicate glass, thermal oxide, and silicon nitride films on silicon

We present precise measurements of the refractive-index dispersion in the 0.6-1.5-microm range of dielectric films commonly used to form optical waveguides on Si. These are thermal SiO(2) and phosphosilicate glasses formed from several types of low pressure chemical vapor deposition and Si(3)N(4) formed by LPCVD. Mode refractive-index measurements were made with absolute accuracies of 1 x 10(-4). We show that for samples greater, similar3 microm thick, the error in the film refractive index, determined by extrapolation of the mode refractive index data of the lowest two modes, is less, similar1 x 10(-4). Annealing studies of the phosphosilicate glass samples show that films containing 2% or more of P reached their equilibrium refractive indices after annealing at 800 degrees C, while undoped silica films require annealing at 1100 degrees C to reach equilibrium.