NITROGEN PROFILES OF THIN SPUTTERED PVD SILICON-NITRIDE FILMS

Thin amorphous silicon nitride films (D = 100 nm) were deposited on silicon substrates by means of argon ion beam sputtering under high vacuum conditions (residual gas pressure below 10(-5) Pa). The nitrogen depth profiles were measured by using the nuclear resonance reaction N-15(p,alphagamma)C-12 at E(res) = 429 keV (GAMMA = 120 eV). The hydrogen concentration was determined by ERDA using a 10 MeV Ne-20 ion beam. Results show that the nitrogen concentration of thin films is inversely proportional to the hydrogen concentration. The nitrogen profiles obtained by NRA and by comparative RBS measurements (He-4+, E0 = 2.0 MeV) showed good agreement. Annealing of the sample in nitrogen atmosphere at 600-degrees-C for 1 h did not influence the nitrogen concentration.