IR SPECTROSCOPIC ELLIPSOMETRY - INSTRUMENTATION AND APPLICATIONS IN SEMICONDUCTORS

We present an IR ellipsometer (550-7000 cm-1) based on a rotating-anal yser 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 thickn esses and porosity in porous silicon multilayers or of boron and phosp horus concentrations in doped silica glasses. Because of its ability t o determine simultaneously the real and imaginary parts of the refract ive index of thin layers this instrument allows more precise spectrosc opy. As an example the spectrum obtained from a layer of silica on sil icon is analysed in normal vibration modes close to those of bulk sili ca.