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Structural and electronic properties of thin fluorite‐structure NiSi 2 , CoSi 2 and FeSi 2 interfaces and precipitates in Si
Author(s) -
Wardle M. G.,
Goss J. P.,
Briddon P. R.,
Jones R.
Publication year - 2005
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200460508
Subject(s) - materials science , fluorite , silicide , crystallography , electronic structure , condensed matter physics , planar , dislocation , dipole , band gap , silicon , schottky barrier , optoelectronics , chemistry , metallurgy , composite material , physics , computer graphics (images) , organic chemistry , diode , computer science
Interface geometry and electronic properties of fluorite‐structure NiSi 2 , CoSi 2 and FeSi 2 layers in {111} oriented silicon are studied using density functional methods. Of the atomically flat geometries studied, NiSi 2 is found to preferentially form an interface where the transition‐metal atoms are 7‐fold coordinated, whereas CoSi 2 and γ‐FeSi 2 both adopt 8‐fold coordinations. Schottky‐barrier heights are detailed for the low energy interface structures of the three disilicides. The localisation of states introduced below the Si valence band and in the band‐gap are detailed for infinite systems, with preliminary results for finite layers simulated by dislocation dipoles also being discussed. Our calculations support the view that gap‐states for silicide precipitates are associated with bounding dislocations rather than the planar interfaces. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)