Nonlinear effect on damage in Si bombarded with 10-to-100-keV C ions

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

We have investigated nonlinear effect on displacement of lattice atoms in Si induced by bombardment with 10-540-keV C ions. Pieces of Si(100) wafer treated with an RCA method were irradiated with 10-540-keV C ions at room temperature. The areal density of displaced lattice atoms was determined from the area of a surface peak of backscattering yields of 2-MeV He ions. The number of displaced Si atoms by single-C-ion bombardment, , has been derived from the fluence dependence of the areal density of displaced Si atoms. Comparing with that by monatomic-C-ion bombardment calculated with SRIM2008, , large nonlinear effect on the displacement of Si atoms has been found. The nonlinear effect is the maximum around 100 keV, where the number ratio of displaced Si atoms per C atom, /(60) is more than 50.