MOLECULAR ION-IMPLANTATION IN SILICON

N-15(2)+ molecular ions were implanted with 10keV (j = 10 mu A/cm(2)) under high vacuum conditions close to room temperature in [100] silico n (c-Si) to study the N-15 depth distributions, particularly the depen dence of peak concentration and dose on the ion fluence. The analysis were performed by the resonant nuclear reaction N-15(p, alpha gamma)C- 12 (NRA). A maximum peak concentration of 65 at.% was measured. Thin s toichiometric silicon nitride layers with a thickness of approx. 20 nm (15 at.% nitrogen at the specimen surface) were produced by this low- energy implantation of N-15(2)+ ions with an ion fluence of 1.5.10(17) ions/cm(2). NRA analysis of 38 keV N-15(2)+ and 19 keV N-15(+) ion im plantations were performed to compare the N-15 depth distributions. No significant changes in the depth distributions are measured, that mea ns, the molecular N-15(2)+ ions are already disintegrated passing the very first atomic layers of the sample during implantation. Non-Ruther ford RES with He-4(+) ions and 3.45 MeV was performed in order to conf irm the results obtained by NRA.