In situ study of the endotaxial growth of hexagonal CoSi{sub 2} nanoplatelets in Si(001)

• Published in: Applied physics letters Vol. 107; no. 22
• Main Authors: Silva Costa, Daniel da, Kellermann, Guinther, Huck-Iriart, Cristián, Giovanetti, Lisandro J., Requejo, Félix G., Craievich, Aldo F.
• Format: Journal Article
• Language: English
• Published: United States 30-11-2015
• Subjects: ANNEALING; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COBALT SILICIDES; DEPOSITS; DISSOLUTION; DISTRIBUTION; INTERFACES; NANOPARTICLES; NANOSTRUCTURES; SILICON OXIDES; SMALL ANGLE SCATTERING; THIN FILMS; X-RAY DIFFRACTION
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4936377

This investigation aims at studying–by in situ grazing-incidence small-angle x-ray scattering–the process of growth of hexagonal CoSi{sub 2} nanoplatelets endotaxially buried in a Si(001) wafer. The early formation of spherical Co nanoparticles with bimodal size distribution in the deposited silica thin film during a pretreatment at 500 °C and their subsequent growth at 700 °C were also characterized. Isothermal annealing at 700 °C promotes a drastic reduction in the number of the smallest Co nanoparticles and a continuous decrease in their volume fraction in the silica thin film. At the same time, Co atoms diffuse across the SiO{sub 2}/Si(001) interface into the silicon wafer, react with Si, and build up thin hexagonal CoSi{sub 2} nanoplatelets, all of them with their main surfaces parallel to Si(111) crystallographic planes. The observed progressive growths in thickness and lateral size of the hexagonal CoSi{sub 2} nanoplatelets occur at the expense of the dissolution of the small Co nanoparticles that are formed during the pretreatment at 500 °C and become unstable at the annealing temperature (700 °C). The kinetics of growth of the volume fraction of hexagonal platelets is well described by the classical Avrami equation.