Surface morphology and reaction at Cu/Si interface—Effect of native silicon suboxide

• Published in: Applied surface science Vol. 252; no. 20; pp. 7572 - 7577
• Main Authors: Benouattas, N., Mosser, A., Bouabellou, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2006; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Copper; Copper silicides; Diffusion; interface formation; Exact sciences and technology; Interface structure and roughness; Morphology; Physics; Silicon suboxide; Solid surfaces and solid-solid interfaces; Solid-state reaction; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Copper silicides; 68.37.Hk; Silicon suboxide; 85.40.Ls; Morphology; 66.30.Ny; Solid-state reaction; 68.55.Jk; Copper; 82.80.Yc; Backscattering; Alpha particles; XRD; Surface states; Surface structure; Thin films; Silicon; Interface reaction; Diffusion; Oxygen; RBS; Annealing; Scanning probe microscopy; Heat treatments; Transition elements; Solid state reaction
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2005.09.010

Copper thin films are deposited by thermal evaporation on unetched and etched monocrystalline silicon. The study by alpha particles backscattering (RBS) raises a strong diffusion of copper in silicon substrates with and without native suboxide layer. On the other hand, the X-rays diffraction shows the formation and the growth of Cu 3Si and Cu 4Si silicides. Whereas the scanning microscopy underlines large crystallites growth surrounded by black zones of silicon coming from the uncovered substrate, independently to the surface state of the substrate, after annealing at high temperature. The presence of native silicon suboxide at Cu/Si interface, influences in a drastic way the minimal temperature to which the interfacial reaction occurs. The oxygen impurities detected by microanalysis, after heat treatment under vacuum, are closely related to the growth of silicides crystallites.