Depth profiles of refractive index in thermally grown and LPCVD oxide films on silicon

Thin and thick silicon oxide films are grown by thermal oxidation of silicon in dry oxygen or by LPCVD from a mixture of monosilane with oxygen or nitrous oxide. Depth profiles of refractive index are determined in these films by monochromatic ellipsometry, with the measurements interpreted by solving an inverse problem within a multilayer model. The differences between the depth profiles are found to be consistent with well-known mechanisms of film growth under the process conditions applied.