Mössbauer study of the Fe-Si phases produced by Fe implantation followed by ion-beam-induced epitaxial crystallization

Iron silicides were produced by 100-keV {sup 57}Fe implantation at room temperature into Si(100), followed by 500-keV Si beam irradiation at 593 K to induce epitaxial crystallization. The iron concentration was varied between 4 and 28 at.{percent}. The M{umlt o}ssbauer spectra associated with {sup 57}Fe probes can be described by means of a broad quadrupole interaction distribution. After thermal treatments at temperatures up to 793 K the spectra become narrower and quadrupole distribution gets closer to that of {beta}-FeSi{sub 2}. The fitted interactions are discussed in terms of those of {gamma}-FeSi{sub 2}, {beta}-FeSi{sub 2}, and {alpha}-FeSi{sub 2} phases which have been observed by high-resolution transmission electron microscopy. Low-temperature measurements of {gamma}-FeSi{sub 2} precipitates prepared by the ion-beam-induced epitaxial crystallization route do not confirm the reported occurrence of magnetic ordering in this system, above 4.2 K. {copyright} {ital 1996 The American Physical Society.}