Molecular ion implantation in silicon

15 N 2 + molecular ions were implanted with 10keV (j=10 μA/cm 2 ) under high vacuum conditions close to room temperature in 〈100〉 silicon (c-Si) to study the 13 N depth distributions, particularly the dependence of peak concentration and dose on the ion fluence. The analysis were performed by the resonant nuclear reaction 15 N(p, αγ) 12 C(NRA). A maximum peak concentration of 65 at.% was measured. Thin stoichiometric 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 15 N 2 + ions with an ion fluence of 1.5·10 17 ions/cm 2 . NRA analysis of 38 keV 15 N 2 + and 19keV 15 N + ion implantations were performed to compare the 15 N depth distributions. No significant changes in the depth distributions are measured, that means, the molecular 15 N 2 + ions are already disintegrated passing the very first atomic layers of the sample during implantation. Non-Rutherford RBS with 4 He + ions and 3.45 MeV was performed in order to confirm the results obtained by NRA.