Study of the Interface Structure of Epitaxial Ultra-Thin Film by an X-Ray Holographic Imaging Method

Abstract

An X-ray holographic method that reconstructs a single layer of atoms at the interface between ultra-thin film and substrate crystal is studied. We applied the method to the analysis of the interface structure of iron-silicide grown on the Si(111) surface, the structure of which is considered to be the CsCl-type FeSi. First we confirmed by simulations that the method is useful to discriminate whether an additional layer at the interface exists or not, using calculated X-ray intensities. Next we applied the method to the analysis of experimental data obtained for Si(111)-2×2-Fe. The result indicated the existence of the interface atoms, corresponding to the B8 model for CsCl-type FeSi.

High‐Resolution Crystal Truncation Rod Scattering: Application to Ultrathin Layers and Buried Interfaces

“…Since this work, a number of interfacial structures of metallic and semiconducting films on Si have been studied using similar methods. Some of the relevant systems include Cu, [ 128 ] Ag, [ 129,130 ] CaF 2 , [ 131,132 ] Ge, [ 133 ] AlN, [ 134 ] FeSi [ 135 ] on Si (111); GaAs, [ 136 ] amorphous‐Si/Ge layers, [ 137 ] and Ge quantum dots on Si (100) [ 94,138 ] ; and, quantum wires of Au on Si (557). [ 139 ] It is worth mentioning that, among these, the studies by Walker et al [ 128 ] and Tweet et al [ 140 ] were among the first to use anomalous CTR scattering to identify the energy‐dependent scattering from specific surface species as a means to extract atomic positions in an interfacial system.…”