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

Real time monitoring of the growth of plasma deposited transparent thi n films by spectroscopic phase modulated ellipsometry (SPME) is presen ted. Two on-line methods of determination of the refractive index n an d the film thickness d are evaluated. The first one is based on the fa st inversion of the Fresnel equations (0.2 s with a conventional PC 48 6 computer). Combining the measurements simultaneously recorded at two photon energies, a 5% relative precision is obtained on 5-6000 Angstr om thick films even deposited at high deposition rate (32 Angstrom s(- 1)). On the other hand, a better precision can be obtained using a lea st squares fit procedure based on single photon energy SPME measuremen ts. In the latter case, it is shown that the product nd can be determi ned with a 1% precision, up to 6000 Angstrom. (C) 1995 American Instit ute of Physics.