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Application of AES micro‐analysis to interface characterization in TiSi diffusion couples: 2—Influence of oxygen
Author(s) -
Quenisset C.,
Naslain R.,
Demoncy P.
Publication year - 1988
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740130204
Subject(s) - titanium , oxygen , analytical chemistry (journal) , diffusion , materials science , silicon , metallurgy , chemistry , physics , organic chemistry , chromatography , thermodynamics
The diffusion of both silicon and oxygen in TiSi couples annealed at 600–700°C under low ( p O 2 = 10 −4 Torr) or high (i.e. in air) oxygen pressures has been studied by AES depth profiling. The AES quantitative analysis of titanium and oxygen was based on the computation of the peak height to background ratios vs. concentration curves for the Ti‐L 3 M 23 M 23 ; Ti‐Li 3 M 23 M 45 and O‐KL 2 L 3 peaks. The element analysis was correlated with the peak shape and EELS spectra. The diffusion of oxygen from the free surface of the sample within the titanium film slows down and eventually stops the extension of the titanium silicide layer formed by diffusion of silicon from the wafer. The former results in the formation of titanium oxides (i.e. TiO, Ti 2 O 3 , or TiO 2 ) and the latter in that of titanium silicides (mainly Ti 5 Si 3 , and TiSi 2 ). For long enough diffusion times, the main silicide in the diffusion zone is TiSi 2 and its growth rejects oxygen in the titanium‐rich part of the couple. Therefore, the TiSi 2 /Si interface is almost free of oxygen.