ELLIPSOMETRIC STUDY OF THERMALLY EVAPORATED GERMANIUM THIN-FILM

The optical properties of thermally evaporated germanium thin films in the spectral range 0.3-1.7 mu m were studied with spectroscopic ellip sometry. The microstructure of these films, including their crystallin ity, density, surface morphology, and surface oxidation, was analyzed with x-ray diffraction, Rutherford backscattering spectrometry, atomic force microscopy (AFM), and Auger electron spectrometry (AES). Parame ters such as the surface roughness and surface-oxidation-layer thickne ss, derived from AFM and AES measurements, were incorporated into our optical model. The complex index of refraction (n and k) of the films was determined throughout the above spectral range and compared with t hat of single-crystal germanium. (C) 1991 Optical Society of America.