ALPHA-ELASTIC RECOIL DETECTION ANALYSIS OF THE ENERGY-DISTRIBUTION OFOXYGEN IONS IMPLANTED INTO SILICON WITH PLASMA IMMERSION ION-IMPLANTATION

Plasma immersion ion implantation was used to implant oxygen ions into silicon with applied voltage pulses of -40 kV and 2.5 mu s length. Po sitive ions, O-2(+) and O+, with a continuous energy distribution betw een O and 40 keV were implanted. Between 3x10(4) and 3x10(5) pulses, c orresponding to nominal doses from 2x10(16) to 2x10(17)/cm(2), were us ed. The resulting oxygen depth profiles were measured with elastic rec oil detection analysis using 13.4 MeV alpha particles. Rutherford back scattering was used to determine possible co-implanted contaminants. T he obtained depth profiles were simulated using a linear superposition of calculated single-energy profiles. The results obtained for the en ergy distribution of the incident ions are compared with calculations obtained from a theoretical model, and the agreement is very good. The incident flux is found to be composed of 34(5)% O-2(+) and 66(5)% Oions with an Fe contamination of similar to 0.5%. (C) 1997 American In stitute of Physics.