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Prediction of orientation relationships and interface structures between α‐, β‐, γ‐FeSi 2 and Si phases
Author(s) -
Visotin Maxim A.,
Tarasov I. A.,
Fedorov A. S.,
Varnakov S. N.,
Ovchinnikov S. G.
Publication year - 2020
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520620005727
Subject(s) - epitaxy , silicide , materials science , silicon , crystallography , thin film , lattice (music) , condensed matter physics , thermal expansion , optoelectronics , layer (electronics) , nanotechnology , composite material , chemistry , physics , acoustics
A pure crystallogeometrical approach is proposed for predicting orientation relationships, habit planes and atomic structures of the interfaces between phases, which is applicable to systems of low‐symmetry phases and epitaxial thin film growth. The suggested models are verified with the example of epitaxial growth of α‐, γ‐ and β‐FeSi 2 silicide thin films on silicon substrates. The density of near‐coincidence sites is shown to have a decisive role in the determination of epitaxial thin film orientation and explains the superior quality of β‐FeSi 2 thin grown on Si(111) over Si(001) substrates despite larger lattice misfits. Ideal conjunctions for interfaces between the silicide phases are predicted and this allows for utilization of a thin buffer α‐FeSi 2 layer for oriented growth of β‐FeSi 2 nanostructures on Si(001). The thermal expansion coefficients are obtained within quasi‐harmonic approximation from the DFT calculations to study the influence of temperature on the lattice strains in the derived interfaces. Faster decrease of misfits at the α‐FeSi 2 (001)||Si(001) interface compared to γ‐FeSi 2 (001)||Si(001) elucidates the origins of temperature‐driven change of the phase growing on silicon substrates. The proposed approach guides from bulk phase unit cells to the construction of the interface atomic structures and appears to be a powerful tool for the prediction of interfaces between arbitrary phases for subsequent theoretical investigation and epitaxial film synthesis.