Segregation and increased dopant solubility in Pt-implanted and laser-annealed Si layers

Abstract

Q‐switched laser irradiation has been used to melt and recrystallize amorphous Pt‐implanted layers formed on the surface of Si single crystals. While the Pt segregated to the surface by an effect related to zone refining, the final impurity depth distribution depended upon substrate temperature in the range 77–620 °K. This observation is correlated with calculations of changing melt dwell times and resolidification velocities. The nonuniform lateral distribution of the segregated Pt at the Si surface is believed to be controlled by constitutional supercooling occurring in the resolidifying melt. In addition, Pt exhibited considerable substitutionality in the Si lattice after laser annealing, corresponding to an effective solubility enhancement of 3 orders of magnitude. This phenomenon is correlated with solute trapping and melt viscosity effects occurring during resolidification.