When a film of CoSi2 on a SiO2 substrate is thermally annealed in an oxidizing ambient in the temperature range, 750 - 1000°C, a SiO₂ layer grows on the surface by depleting the film of its Si. As a result, the chemical composition of the film passes through a sequence of silicides with increasing metal content. The film also breaks up into islands. This morphological instability is observed also for pure Co film on SiO₂ when annealed in vacuum. We show that less than 10 atomic percent of Si, or higher, in Co suppresses this instability under vacuum annealing. The oxidation of a CoSi₂ film on a Si <111> substrate establishes that the displacement of Si atoms against Co atoms in the silicide does not create a morphological instability. The irradiation of a film on SiO₂ prior to oxidation by Kr ions whose range is commensurate with the thickness of the film can partly suppress this instability during oxidation under certain circumstances.

Date Published: 9 April 1985
PDF: 7 pages
Proc. SPIE 0530, Advanced Applications of Ion Implantation, (9 April 1985); doi: 10.1117/12.946481

Published in SPIE Proceedings Vol. 0530:
Advanced Applications of Ion Implantation
Michael I. Current; Devindra K. Sadana, Editor(s)