Carbon-build-up analysis of Si surfaces bombarded with 10-to-100-keV C ions

Naramoto, Hiroshi*; Takahashi, Yasuyuki; Yamada, Keisuke; Chiba, Atsuya; Adachi, Masahiro*; Saito, Yuichi; Maeda, Yoshihito; Narumi, Kazumasa

We will present the analysis of carbon concentration built up on Si surfaces bombarded with 10-, 50- and 400-keV C ions with a nuclear reaction C(d, p)C using 1.2-MeV D. The fluence dependence of the carbon concentration in the surface layer of C-bombarded Si that we obtained is inconsistent with the one estimated from the assumption that all of the carbon atoms due to an incident C ion remain at the surface. The measured concentration is higher than the estimated one at lower fluence than 10 C/cm, while the rate of increase of the concentration becomes smaller at higher fluence than 10 C/cm and the concentration is lower than the estimation at last. The observed fluence dependence is reproduced well by a rate equation describing the carbon concentration at the surface as a function of the C ion fluence based on an assumption that the carbon concentration is determined by the competition between the sputtering and the carbon deposition or implantation which includes the contribution of C-bombardment-induced recoil of the surface contaminants.