SPECTROSCOPIC ELLIPSOMETRY INVESTIGATION OF AMORPHOUS-SILICON NITRIDETHIN-FILMS

It has been reported earlier that the attenuation lengths of photoelec trons from very thin amorphous silicon nitride films (3 to 11 nm) incr ease with film thickness. These changes were attributed to systematic variations in the film density. Spectroscopic ellipsometry has been us ed here as an independent technique to evaluate the refractive indexes of several of the same films. The ellipsometric results are consisten t with the earlier finding that the relative densities of these films vary with thickness. The density variations may be attributed to eithe r structural changes in the films or differences in the oxygen content of the films with film thickness.