REAL-TIME MONITORING OF THE GROWTH OF TRANSPARENT THIN-FILMS BY SPECTROSCOPIC ELLIPSOMETRY

Real time monitoring of the growth of plasma deposited transparent thin films by spectroscopic phase modulated ellipsometry (SPME) is presented. Two on-line methods of determination of the refractive index n and the film thickness d are evaluated. The first one is based on the fast inversion of the Fresnel equations (0.2 s with a conventional PC 486 computer). Combining the measurements simultaneously recorded at two photon energies, a 5% relative precision is obtained on 5-6000 Angstrom thick films even deposited at high deposition rate (32 Angstrom s(-1)). On the other hand, a better precision can be obtained using a least squares fit procedure based on single photon energy SPME measurements. In the latter case, it is shown that the product nd can be determined with a 1% precision, up to 6000 Angstrom. (C) 1995 American Institute of Physics.