Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Iron implanted and subsequently annealed n-type Si(111) was
studied by conversion electron Mössbauer spectroscopy for phase analysis
and Auger electron spectroscopy for sputter depth profiling and element mapping.
During implantation (200 keV, 3 x 1017 cm-2, 350 °C) a mixture of ß-
and a-FeSi2 and after the subsequent annealing (900 °C for 18 h and
1150 °C for 1 h) a complete transition to the ß- and a-phase can
be detected. The as-implanted profile has Gaussian shape which becomes broad
during annealing at 900 °C to a plateau-like profile and shows only
a slight broadening and depth depending fluctuations of the iron concentration
after the 1150 °C annealing. With scanning Auger electron spectroscopy
the lateral iron and silicon distribution were investigated show for the
sample annealed at 900 °C large separated ß-FeSi2 precipitates
which grow due to the process of Ostwald ripening. At 1150 °C additionally
coalescence of the precipitates occur and a wide extended penetration a-FeSi2
network structure is formed.