Periodic regrowth phenomena produced by laser annealing of ion-implanted silicon

We have discovered that interference effects extant during pulsed laser irradiation annealing of ion-implanted silicon produce periodic property variations in the annealed material that mimic the interference pattern. These are manifest at near-annealing threshold power densities as surface ripple and at higher power densities may be revealed by etching. The surface ripple observed at low power densities is correlated with the occurrence of polycrystalline silicon regions in the annealed material. Our observations suggest that surface melting and epitaxial regrowth are responsible for the annealing effect.