Atomistic Simulation of Damage Accumulation during Shallow B and As Implant into Si

We have used atomistic simulations to analyze differences experimentally observed in damage distributions of low-energy B and As implant at room temperature. The proximity to the surface, which favors damage accumulation, and the variations in the damage topology due to the different ion mass of B and As are the key factors to understand their damage profiles. Damage distribution after a B implant presents two peaks: a shallow one corresponding to an amorphous layer extending from the surface, and a deep one due to the excess Si interstitials close to the mean projected range of the implant. On the contrary, the compact damage generated by the heavy As ions accumulates both from the surface and from the mean projected range, leading to a continuous amorphous layer that extends from the surface to beyond the mean projected range.