Polyatomic-Ion Implantation Damage in Silicon

We have investigated the number, Nd, of displaced lattice atoms in room-temperature implantation in Si of polyatomic-carbon-ion beams (Cₙ⁺ and C_n-xOₓ⁺) for several values of n, using the backscattering-channeling-effect technique. For each ion species the same energy (8.8 keV) per carbon and the same atomic fluence and flux were used. Nd increases rapidly with increasing n, indicating that the deposited-energy density within the collision cascade is a key factor in determining how much damage is created and retained.