a Study of Ion Implantation Damage and Annealing of Silicon Utilizing Differential Reflectometry.

Differential reflectometry was utilized for the first time in a systematic study of implantation damage and post-implantation annealing behavior of silicon. Arsenic, silicon and boron ions of various energies and doses were utilized as implantation species. It has been demonstrated that differential reflectometry is fast and nondestructive. The technique allows an immediate assessment of the changes in the electronic structure caused by ion implantation or annealing and a direct identification of the damaged structures of the implanted layer. A new method for data reduction from differential reflectograms has been developed, which provides quantitative information on the thickness of implantation-induced amorphous layers in silicon. The effect of implantation energy, dose, species, annealing temperature, annealing time, and wafer orientation on damaged structures created during implantation has been studied. Comparisons of our findings with the results obtained by cross-sectional transmission electron microscopy are presented. It is shown that the results from this study utilizing differential reflectometry not only confirm the current understanding of ion implantation damage, but also provide additional detailed understanding and analysis. A detailed study on the isothermal annealing of implantation-induced amorphous silicon via solid phase epitaxial regrowth has been conducted. Four distinguished annealing stages (regimes) have been found which represent different migration rates of the amorphous/crystalline interface. Mechanisms for these four regimes are discussed. The activation energies for Regimes I, II, and III were found to be 0.27 eV, 2.3 eV, and 2.3 eV, respectively. It was further found that the concentration of the implanted species has a strong effect on the solid phase epitaxial regrowth.