Composition and porosity of multicomponent structures: porous silicon as a three-component system

It is shown for the system porous silicon (por-Si)-silicon (Si) that effective nondestructive investigation of the interfacial morphology of layered semiconductor systems and of the composition of multicomponent layers by ellipsometry and Rutherford backscattering is possible. Both methods were used to determine the percentage composition of the main components of por-Si: crystal silicon, silicon oxide, and voids (porosity). It is shown that por-Si obtained by pulse-anodization contains a substantial quantity of silicon oxide. It is also shown that spectral ellipsometry can be used to determine the specific ratio of individual layers or components of multilayer and multicomponent systems (provided that the spectral dispersion of the optical constants of these components is known).