Application of reflectance studies to layered samples: SiO x on InSb

Spatially resolved optical micro‐reflectometry in the visible region (from 400 nm to 800 nm) is used to study InSb substrates covered with SiO x (1 < x < 2) films of known thicknesses. Using optical constants (refractive index and extinction coefficient) for uncoated InSb derived from two successive reflectance measurements carried out in air and oil, a model of absorbing films on an absorbing substrate was used to calculate the reflectance. Comparison of measured and calculated reflectances for SiO 2 films over InSb demonstrate the validity of the model for an absorbing substrate covered with a homogeneous layer. Optical constants for the SiO x layers are obtained from comparisons between experimental and calculated reflectance curves.