Electrical properties of the TiSi2-Si transition region in contacts: The influence of an interposed layer of Nb

Citation
J. Aberg et al., Electrical properties of the TiSi2-Si transition region in contacts: The influence of an interposed layer of Nb, J APPL PHYS, 90(5), 2001, pp. 2380-2388
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF APPLIED PHYSICS
ISSN journal
0021-8979 → ACNP
Volume
90
Issue
5
Year of publication
2001
Pages
2380 - 2388
Database
ISI
SICI code
0021-8979(20010901)90:5<2380:EPOTTT>2.0.ZU;2-4
Abstract
The influence of an interposed ultrathin Nb layer between Ti and Si on the silicide formation and the electrical contact between the silicide formed a nd the Si substrate is investigated. The presence of the Nb interlayer resu lts in the formation of ternary alloy (Nb,Ti)Si-2 in the C40 crystallograph ic structure adjacent to the Si substrate. Depending on the nature of the S i substrates and/or the amount of the initial Nb, the interfacial C40 (Nb,T i)Si-2 leads, in turn, to either epitaxial growth of a highly faulted metas table C40 TiSi2 or formation of the desired C54 TiSi2 at a lower temperatur e than needed for it to form in reference samples with Ti deposited directl y on Si. On p-type substrates doped to various concentrations, the Nb also leads to a considerably lower specific contact resistivity than that obtain ed in the reference samples: a twofold to fourfold reduction in the contact resistivity is found using cross-bridge Kelvin structures in combination w ith two-dimensional numerical simulation. As C40 (Nb,Ti)Si-2 forms at the i nterface when an interfacial Nb is present, the interface characterized is likely to represent the one between (Nb,Ti)Si-2 and Si. For the reference s amples, the interface studied is between TiSi2 and Si. (C) 2001 American In stitute of Physics.