ANNEALING EFFECTS ON SILICON-RICH OXIDE-FILMS STUDIED BY SPECTROSCOPIC ELLIPSOMETRY

Annealing effects on silicon-rich oxide films deposited by plasma enha nced chemical vapor deposition are studied by spectroscopic ellipsomet ry. From the variations of the film thickness and optical functions ca used by thermal treatments at two different temperatures the propertie s of the different films are derived. Hydrogen and OH release and stru ctural reordering are recognized to be responsible both for thickness decrease and Si-Si bond formation. In samples far from stoichiometric SiO2?, the presence of Si-Si bonds after high temperature annealing ac counts for both refractive index and extinction coefficient increase. Such effects are found to be directly linked to the silicon content in the films. (C) 1998 Elsevier Science S.A. All rights reserved.