| AVS 58th Annual International Symposium and Exhibition | |
| Thin Film Division | Thursday Sessions |
| Session TF1-ThM |
| Session: | Post-Deposition Processing and Characterization of Thin Films |
| Presenter: | Alejandro González González, Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Spain |
| Authors: | A. González González, Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Spain G.M. Alonzo Medina, Centro de Investigaciones y de Estudios Avanzados del IPN, CINVESTAV Unidad de Mérida, Mexico A.I. Oliva, Centro de Investigaciones y de Estudios Avanzados del IPN, CINVESTAV Unidad de Mérida, Mexico C. Polop, Universidad Autónoma de Madrid, Facultad de Ciencias, Spain E. Rodríguez Cañas, Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Spain J.L. Sacedón, Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Spain E. Vasco, Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Spain |
| Correspondent: | Click to Email |
The processes controlling shape transformations during post-deposition treatments attract great interest due to their technological implications. As an example, residual stress relaxation during thermal annealing could influence component lifetime and performance in applications ranging microelectronics to mechanical coatings, affecting their functional properties [1]. In this work, we investigate the morphology evolution during thermal annealing at 0.2 Tmelting in polycrystalline Au(111) films using atomic force [scanning electron] (AFM [SEM]) microscopies and x-ray diffraction in order to follow both shape and structural transformations of surface features for different annealing times. Before annealing, a high density of round-like surface grains ―which are surface components of an underlying competitive columnar microstructure―, is observed. During annealing, surface grains merge together into “multigrain” structures that expand laterally up to a saturation size, suggesting a size-dependent phenomenon controlling surface recrystallization. By comparison with Au polycrystalline growth fronts for the same temperature range [2] (T zone of the zone models [1]), we can relate the annealing–generated multigrain structures to the incipient formation of extended sub-micrometric-sized plates that are observed for thinner films. They contain many small surface grains with low-angle or no inner grain boundaries [2]. The small amount of material to be recrystallized for each component favors the multi-component extension of recrystallized zone. Interestingly, results here reported concerning the recrystallization phenomenon are discussed on the basis of local interactions between surface grains triggering plausible elastic/plastic mechanisms of stress accommodation (grain zipping and shear strain) and relaxation by surface diffusion processes [1,3], which in principle seems not be very different from those expected in the coalescence stage at the T zone.
[1] L. B. Freund and S. Suresh, Thin Film Materials: Stress, Defect Formation and Surface Evolution (Cambridge University Press, Cambridge, England, 2003) and references therein.
[2] C. Munuera et al., J. Vac. Sci. Technol. A 22, 1767 (2004)
[3] A. González-González et al., “Morphology evolution of thermally annealed polycrystalline thin films” (submitted)