INCOHERENT SUPERPOSITION IN ELLIPSOMETRIC MEASUREMENTS

A relationship between Jones and Mueller matrices originally derived f or random media is applied to incoherence effects in photometric ellip sometry. Such effects are for example depolarization after reflection from a sample with varying film thickness or from a layer which is thi cker than the coherence length of the incident light. The main task is to calculate the expectation value of a statistical ensemble. For the important case of thick layers, this expectation value is derived in a symbolic form. Results calculated with this method for transmission ellipsometry, ellipsometry at the back surface of the substrate and th e determination of the optical constants at the substrate-layer interf ace are compared with measurements. (C) 1997 Elsevier Science S.A.