Progress in computer simulation for ion-solid interaction

The theoretical investigation of interactions of ions with solids becomes increasingly popular, using computer simulation. There are two different kinds of computer simulation codes: binary collision approximation (BCA) codes and molecular dynamics (MD) codes. MD codes handle the multiple interactions of a colliding atom with the surrounding target atoms and the interactions between the target atoms. The BCA method saves computing time by introducing physical models properly by describing the ion-solid interaction of interest. BCA codes do not include the many body interaction. The deflection angle, the energy loss, and the time integral are calculated assuming free target atoms. They are successfully applied to ion implantation, channeling, sputtering, ion range and surface scattering. When high-fluence ion beams are bombarded on multicomponent material, near-surface compositional alteration is an unavoidable phenomenon which results from a combination of several kinetic processes and thermal processes. Using the ACAT-DIFFUSE code, we show some simulated results of sputtering and reflection from a ternary alloy, high-temperature sputtering from a Ni-Cu alloy, and depth profiles due to low-energy B ion implantation into an amorphized Si target