QUANTITATIVE-ANALYSIS OF THE LIGHT-SCATTERING EFFECT ON POROUS SILICON OPTICAL MEASUREMENTS

The effect of light scattering on standard optical measurements of thi n films is presented. According to the Davies-Bennett theory, the scat tering is introduced quantitatively in the calculation of the energy t ransmission and reflection coefficients. The relations of continuity a re adapted to perform reflectivity simulation in the case of rough int erfaces. A comparison with reflectivity spectra of PSi layer is made a nd shows that when the scattering is neglected, the absorption coeffic ient of the material is overestimated. Using the roughness amplitude d ependence vs. the current density of formation, we perform a simulatio n of a double layer structure. It then becomes possible to characteriz e by optical analysis the quality of the interfaces in multilayers, wh ich presently is under considerable investigations. (C) 1997 Elsevier Science S.A.