Reflection high energy electron diffraction study of CoSi₂/Si multilayer structures

The epitaxial perfection and microstructure of Si/CoSi₂/Si heterostructures have been examined by various techniques, such as transmission electron microscopy and Rutherford backscattering spectroscopy. In this paper, an in situ reflection high energy electron diffraction (RHEED) pattern investigation of Si/CoSi₂/Si double heterostructures grown on Si(111) by solid phase epitaxy is presented. During the thermal annealing of a Co/Si film deposited in the stoichiometric ratio of CoSi₂ at room temperature, RHEED patterns show directly the formation stages of CoSi₂ as well as the crystallinity of the films. A very sharp (1 × 1) RHEED pattern of a CoSi₂ single layer grown on Si(111) has been obtained in our experiment. Ultrathin silicon layers grown on top of CoSi₂ showed a combination of the Si(7 × 7) pattern and the CoSi₂(1 × 1) pattern. From this study, additional information on the process of formation of the Si/CoSi₂/Si multilayer structure is obtained.