Evidence for a Self-Propagating Melt in Amorphous Silicon upon Pulsed-Laser Irradiation

Abstract

A double-peak structure is observed in the Cu concentration profile after low-energy pulsed-laser irradiation of Cu-implanted Si. From the Cu surface segregation a primary melt depth is inferred. In addition, Cu segregation at the depth of the amorphous-crystal interface gives evidence for a secondary melt propagating through the amorphous layer towards the crystalline substrate. The results imply a large difference in melting temperature, heat of melting, and heat conductivity between amorphous Si and crystalline Si.