Dario Ferreira Sanchez

Aging effects on the nucleation of Pb nanoparticles in silica

The ion beam synthesis of Pb nanoparticles (NPs) in silica is studied in terms of a two step thermal annealing process consisting of a low temperature long time aging treatment followed by a high temperature short time one. The samples are investigated by Rutherford backscattering spectrometry and transmission electron microscopy. The results obtained show that highly stable Pb trapping structures are formed during the aging treatment. These structures only dissociate at high temperatures, inhibiting the nucleation of NPs in the metallic phase and causing an atomic redistribution that renders the exclusive formation of a two dimensional, uniform and dense array of Pb NPs at the silica–silicon interface. The results are discussed on the basis of classic thermodynamic concepts.

X-ray μ-Laue diffraction analysis of Cu through-silicon vias: A two-dimensional and three-dimensional study

Here, white X-ray μ-beam Laue diffraction is developed and applied to investigate elastic strain distributions in three-dimensional (3D) materials, more specifically, for the study of strain in Cu 10 μm diameter–80 μm deep through-silicon vias (TSVs). Two different approaches have been applied: (i) two-dimensional μ-Laue scanning and (ii) μ-beam Laue tomography. 2D μ-Laue scans provided the maps of the deviatoric strain tensor integrated along the via length over an array of TSVs in a 100 μm thick sample prepared by Focused Ion Beam. The μ-beam Laue tomography analysis enabled to obtain the 3D grain and elemental distribution of both Cu and Si. The position, size (about 3 μm), shape, and orientation of Cu grains were obtained. Radial profiles of the equivalent deviatoric strain around the TSVs have been derived through both approaches. The results from both methods are compared and discussed.

New approach for structural characterization of planar sets of nanoparticles embedded into a solid matrix

In this work we demonstrate that Medium Energy Ion Scattering (MEIS) measurements in combination with Transmission Electron Microscopy (TEM) or Grazing Incidence Small Angle X-Ray Scattering (GISAXS) can provide a complete characterization of nanoparticle (NP) systems embedded into dielectric films. This includes the determination of the nanoparticle characteristics (location, size distribution and number concentration) as well as the depth distribution and concentration of the NP atomic components dispersed in the matrix. Our studies are performed considering a model case system consisting of planar arrangements of Au NPs (size range from 1 to 10 nm) containing three distinct Au concentrations embedded in a SiO2 film.

Tailoring the blueviolet photoluminescence from Sn-implanted SiO 2 using a two-step annealing process

The blue?violet photoluminescence (PL) response of ion beam synthesized Sn nanoparticles (NPs) in silica is studied in samples submitted to a two-step thermal annealing process. This process consists of a low temperature and long time ageing treatment (523?K, 100?h) followed by a high temperature and short time one (T?>?773?K, 0.5?h). The comparison between aged and non-aged control samples by means of transmission electron microscopy observations and Rutherford backscattering spectrometry measurements demonstrates that the ageing treatment causes the formation of a more thermally stable and dense array of rather small Sn NPs. This phenomenon is correlated with the enhancement in the blue?violet PL intensity caused by the formation of luminescent defects at the NP/matrix interface region, persisting even at annealing temperatures as high as 1373?K.