IR SPECTROSCOPIC ELLIPSOMETRY - INSTRUMENTATION AND APPLICATIONS IN SEMICONDUCTORS

We present an IR ellipsometer (550-7000 cm-1) based on a rotating-analyser configuration and a Fourier transform spectrometer. The stability, sensitivity and accuracy of the instrument are evidenced by examples. A few applications are presented such as the determination of thicknesses and porosity in porous silicon multilayers or of boron and phosphorus concentrations in doped silica glasses. Because of its ability to determine simultaneously the real and imaginary parts of the refractive index of thin layers this instrument allows more precise spectroscopy. As an example the spectrum obtained from a layer of silica on silicon is analysed in normal vibration modes close to those of bulk silica.