PRECISE DETERMINATION OF H-RECOIL CROSS-SECTIONS FOR 1.5-3.0 MEV HE IONS

The differential recoil cross sections of H have been determined for 1 .5-3.0 MeV He+ incidence. In order to obtain precise data, we have per formed simultaneous detection and spectrum simulation of recoiled H an d backscattered He. In addition, a careful cross check has been made b y secondary ion mass spectrometry (SIMS). The present results have rev ealed a pronounced contribution from a nuclear short-range interaction . The He+ energy and recoil angle dependence of the H recoil cross sec tions are well reproduced by adding the nuclear term, which is simply derived from effective range theory. Our computer simulation program o f elastic recoil combined with Rutherford backscattering spectra makes it possible to determine the depth distributions of H together with o ther elements absolutely, without any ambiguities. The present elastic recoil analysis is employed to determine the H composition of amorpho us Si(H) films deposited on Si wafers. An excellent agreement, better than 5%, is obtained between the elastic recoil and SIMS analyses.