Depth analysis of buried iron disilicide formation by Fe ion implantation into Si.

The depth distribution of the iron disilicide phases (α-FeSi[sub 2] and β-FeSi[sub 2]) was investigated nondestructively by depth-selective conversion-electron Mo¨ssbauer spectroscopy after Fe[sup +] implantation (200 keV, 3x10[sup 17] cm-2) and after subsequent rapid thermal annealing (RTA) at 900 °C for 30 s. The depth profiles of the two phases were found to be correlated with the Fe concentration profiles as determined by Auger electron sputter depth profiling. For the as-implanted state a broad distribution of a phase mixture of α- and β-FeSi[sub 2] is observed. Subsequent RTA induces a layered structure including a buried β-FeSi[sub 2] layer with a high phase content of 90% near 220 nm. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]