Stability of scattered hydrogen signals from a-C:H films during He-induced elastic recoil detection analysis

Abstract

The hydrogen (H) loss of hydrogenated amorphous carbon (a-C:H) films, such as polymer-like, diamond-like, and graphite-like carbon films, was evaluated during elastic recoil detection analysis (ERDA) conducted using 3.4 MeV He2+. Films were formed on Si substrates via a plasma-based ion implantation and deposition method. The Raman scattering spectrometry of the films was then conducted, and except for the case of the polymer-like carbon film that had a strong photoluminescence background, two characteristic peaks corresponding to the disorder and graphite bands were observed in all cases. ERDA measurements indicated that there was no H loss in films with weak or negligible photoluminescence, whereas a decrease in H signals was clearly observed for the film with strong photoluminescence. The polymer polyphenylenesulfide (PPS: C6H4S), which is used as a standard material for ERDA measurements, showed a significant decrease in H signals under the same conditions. In comparison with the PPS, we concluded that a-C:H films with negligible photoluminescence can be used as standard materials for ERDA measurements.