Optical-field-induced surface nanobumps in near-infrared laser direct cleaning of nanoparticles on silicon.

The evolution of surface damage in laser direct cleaning (LDC) of nanoparticulate contamination on silicon (Si) was theoretically and experimentally investigated. Nanobumps with a volcano-like shape were found in near-infrared laser cleaning of polystyrene latex nanoparticles on Si wafers. According to the finite-difference time-domain simulation and the high-resolution surface characterization, unusual particle-induced optical field enhancement in the vicinity of the interface between Si and nanoparticles is mainly responsible for the generation of volcano-like nanobumps.