FABRICATION AND CHARACTERIZATION OF GRADED REFRACTIVE-INDEX SILICON OXYNITRIDE THIN-FILMS

Oxynitride films with continuous variations of the optical index with thickness were grown by electron cyclotron resonance plasma-enhanced c hemical vapor deposition using silane as a silicon precursor and oxyge n and nitrogen as plasma gases. Specific linear and parabolic index pr ofiles were fabricated by computerized-control gas flow. These gradien t index layers were characterized by spectroscopic ellipsometry. The d ata reduction was performed by polynomial analysis. The validity of th e ellipsometric results was also verified by performing an in-depth an alysis via the chemical etching of the gradient index layers. (C) 1997 American Vacuum Society.