DETERMINATION OF THIN-FILM OPTICAL-PROPERTIES BY THE PHOTOACOUSTIC OPC TECHNIQUE

Through the use of maxima and minima of interference fringes in transm ittance spectra registered by the open photoacoustic cell (OPC) detect ion technique, we have determined the refraction index n and thickness d of aluminium nitride thin films which had previously been deposited on opaque and transparent substrate. The results for the transparent substrate are in agreement with those obtained from the transmission s pectra. To determine n as a function of lambda we developed a novel pr ocedure for the analysis of the OPC spectra. The n values so obtained were introduced in an appropriate Airy transmittance function, and the ir numerical evaluation permits the reproduction of the experimental t ransmittance OPC data and optical curves. This scheme was used to esta blish the uniqueness of the calculated data.