Molecular dynamics simulations using improved Tersoff–Brenner potential parameters were performed to investigate Cl ⁺ etching of a {2×1} reconstructed Si(100) surface. Steady-state Si etching accompanying the Cl coverage of the surface is observed. Furthermore, a steady-state chlorinated reaction layer is formed. The thickness of this reaction layer is found to increase with increasing energy. The stoichiometry of SiCl _x species in the reaction layer is found to be SiCl : SiCl ₂: SiCl ₃=1.0:0.14:0.008 at 50 eV. These results are in excellent agreement with available experimental data. While elemental Si products are created by physical sputtering, most SiCl _x (0< x <4) etch products are produced by chemical-enhanced physical sputtering.