Study by GISAXS and TEM of coherent CoSi2 nanoplates buried in Si(001)

P.C. DOS SANTOS CLARO; L. J. GIOVANETTI; F. G. REQUEJO; LIANG ZHANG; MONTORO L. A.; RAMIREZ A. J.; G. KELLERMANN; A. F. CRAIEVICH

Hamburg

Congreso; GISAXS2011; 2011

DESY

The development of new procedures for size reduction of components for modern silicon-based integrated circuit (IC) is nowdays an important technological issue. Many authors gave great attention to investigations of self-ordered materials at nanoscale level exhibiting low resistivity and high thermal stability.1-3 Particularly important, not only for fundamental sciences but also for modern silicon-based IC technologies, are the studies of silicon/metal interactions, nucleation processes, atomic diffusion and growth of silicide nanoparticles embedded in silicon matrices. In this work we describe a controlled and reproducible procedure for obtaining very thin hexagonal CoSi2  nanoplates within a Si(100) wafer. A thin silica film containing Co atoms was deposited on the surface of a Si(100) wafer and annealed at 750°C. This thermal treatment was responsible for the formation of spherical Co nanoparticles embedded in the silica film and a few atomic layer thick CoSi2 nanoplatelets within the Si(100) wafer. The morphology, structure and spatial orientation of the CoSi2 nanoplatelets incrusted in the Si crystal were characterized by synchrotron grazing-incidence small-angle x-ray scattering (GISAXS) and transmission electron microscopy (TEM). The experimental results show that the CoSi2  nanoplates have nearly regular hexagonal shape and a uniform thickness. It was also observed that the CoSi2 nanoplate lattice is coherent with the Si lattice and parallel to each one of the four planes of the {111} crystallographic form of the silicon lattice, indicating that the CoSi2 crystals grow with a Si{111} habit plane.  This work was supported by LNLS, CNPq and FAPESP, Brazil; PICT 2008‐00038 (ANPCYT) and PIP 112‐200801‐03079 (CONICET), Argentina; and CIAM collaborative project (CONICET/CNPq).   [1] Barth, J. V.; Costantini, G.; Kern, K.,. Nature 2005, 437 (7059), 671-679. [2] Chen, L. J., Metal Silicides: Journal of Operations Management 2005, 57 (9), 24-31. [3] Adams, D. P.; Yalisove, S. M.; Eaglesham, D. J., Journal of Applied Physics 1994, 76 (9), 5190-5194.