Growth of patterned thin epitaxial CoSi2-films by a titanium oxide mediated epitaxy process

A new method for fabricating thin patterned CoSi2 layers has been studied. The silicide layers were generated by a solid phase epitaxy process, in whi ch Co and Ti were deposited on a thin chemical oxide on Si(100) substrates. Rapid thermal annealing (RTA) of this structure leads to the formation of epitaxial CoSi2 with a capping layer on top. Two-step annealing in a formin g ambient gas produces high quality epitaxial layers with a capping layer w hich can be easily removed by wet chemicals. A layer structure consisting o f 30 nm SiO2 and 300 nm Si3N4, which is patterned using conventional optica l lithography and dry etching, induces a stress field into the underlying l ayers near the patterning edges. This leads to a formation of separated CoS i2 layers during the silicide formation caused by the anisotropic diffusion of the atoms in the stress field. Such layers show nearly uniform gaps of approximately 100 nm in width. (C) 2000 Elsevier Science B.V. All rights re served.