Implantation and growth of large β-FeSi2 precipitates and α-FeSi2 network structures in silicon

Abstract

Iron implanted and subsequently annealed n-type Si(111) was studied by conversion electron Mössbauer spectroscopy and Auger electron spectroscopy. Results of Mössbauer spectroscopy indicate the formation of a mixture of β- and α-FeSi2 due to the implantation and a complete transition of the mixture to the β and the α phase after annealing at 900 °C for 18 h and 1150 °C for 1 h, respectively. The iron concentration profiles determined with Auger electron sputter depth profiling are Gaussian shaped for the as-implanted and broadened with depth depending fluctuations for the annealed samples. Investigations of the annealed samples with scanning Auger electron spectroscopy show the formation of large precipitates with, depending on the annealing procedure, different structures.