Structural properties of ion‐beam‐synthesized β‐FeSi2 in Si(111)

A continuous buried β‐FeSi2 layer was obtained by implantation of 200 keV Fe+ ions into Si(111) wafers at elevated temperature. During the subsequent rapid thermal annealing at 1150 °C for 10‐s, a continuous buried layer of the metallic α‐FeSi2 phase is formed. During the second annealing step at 800 °C, the α phase is completely transformed into the semiconducting β phase. The epitaxial relationship between the β‐FeSi2 and the silicon substrate was investigated by transmission electron microscopy. It was found that the β‐FeSi2(010) plane grows parallel to the Si(111) substrate. Two different azimuthal orientations were observed. For the first azimuthal orientation, the β‐FeSi2[001] direction is oriented almost parallel to one of the three Si〈110〉 directions lying in the interface. In the second azimuthal orientation, the β‐FeSi2[100] direction lies parallel to one of the Si〈110〉 directions in the interface. The lattice parameter mismatch and the growth mechanism must be considered to be the main reasons ...