Raman scattering study of rapid thermal annealing of As+-implanted Si

Rapid thermal annealing of Si after implantation with 60-keV 75As+ ions was studied using Raman scattering. Spectra were measured at different stages of annealing. It was found that the as-implanted amorphous phase was first transformed into the higher-order amorphous phase before the transformation into the crystalline phase. Regrowth of the crystalline phase occurred only from the substrate side, and no polycrystalline regions could be detected at the intermediate stages of annealing. Electrical activation of the implanted As dopant proceeded simultaneously with crystal regrowth, and complete activation coincided with the disappearance of the amorphous phase. Changes in the Raman spectra of the implanted and annealed crystalline layer caused by the contribution of free electrons were found, allowing the concentration of activated free carriers to be determined.