X-ray Bragg-Surface Diffraction: A Tool to Study In-Plane Strain Anisotropy Due to Ion-Beam-Induced Epitaxial Crystallization in Fe+-Implanted Si(001)

Abstract

In-plane strain anisotropy was clearly observed by the X-ray Bragg-surface diffraction technique in the silicon lattice surrounded by nanoparticles that were synthesized by an ion-beam-induced epitaxial recrystallization process of Fe-implanted amorphous Si layer. High resolution transmission electron microscopy images have shown the occurrence of metallic spherical and plate-like γ-FeSi 2 nanoparticles in the implanted/recrystallized region. These were found in different orientations within the sample, being responsible for the strain anisotropy detected. The striking anisotropy effect, due to mainly the plate-like nanoparticles in the recrystallized region, appears when comparing two (-6.04° and 83.96°) (002) rocking curves at Bragg-surface diffraction exact condition. Furthermore, the mappings of the (111) Bragg-surface diffraction reflections show an evident anisotropy between φ -6.04° and 83.96° mappings and also a marked broadening of the implanted sample profile as compared to that of the Si (matrix). Reciprocal space maps obtained for both perpendicular directions clearly exhibit this anisotropic effect in the q x direction, thus confirming the Bragg-surface diffraction results.