Characterization of semiconductor layered structures by spectroscopic ellipsometry.

摘要

Spectroscopic ellipsometry (SE) is a non-destructive optical technique suitable for the characterization of materials. The measurement is based on the accurate determination of the change of polarization state of a polarized incident light beam after interaction with the specimen. In this work, a rotating analyzer type spectroscopic ellipsometer has been constructed and aligned for the non-destructive characterization of semiconductor materials in the wavelength range from UV to NIR. New results on the mathematical formulation for layers of gradually varying dielectric functions have been obtained and included in the software developed for the analysis of the experimental SE spectra. With these software programs, the interpretation of the measured SE spectra of complex structures becomes possible by using appropriate physical models and non-linear least-square fitting.; The system is first tested by a few different types of material systems, such as thermally grown SiO{dollar}sb2{dollar} on Si substrate and SIMOX structures. Then, it is applied to the study of a series of ion beam synthesized (IBS) material systems, such as SiC/Si heterostructures formed by carbon implantation into silicon, and CoSi{dollar}sb2{dollar}/Si layered structures formed by cobalt implantation into silicon. From the ellipsometric spectra of these samples, useful information on these material structures have been obtained and discussed.