Search

In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on or inside SiC is discussed. Optimization of PIXE acquisition parameters was performed using as reference, a thin Al film (2.5 nm) thermally evaporated onto silicon carbide substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.02 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 µm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9x1020 at/cm3 in good agreement with SIMS measurements, and the LOD was estimated to be 6x1018 at/cm3.

An absorber-emitter system was fabricated using a multi-layer structure of amorphous silicon and silicon oxide thin films. The layers were deposited using RF magnetron sputtering system. The thin films were alternated in a periodic structure to form a one-dimensional photonic crystal. Each period in the crystal consisted of one layer of 57 nm thick silicon and a 100 nm thick silicon oxide layer. Several samples were prepared consisted on different periods (N= 1, 2, 3, 4, 5 and 10). Rutherford Backscattering Spectrometry technique (RBS) was used to verify the number of layers and their alternation, checking the thicknesses and determine the real stoichiometry in each layer of Si and SiOx.

International audience; In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a rapid, nondestructive and quantification of Boron in ultra-thin films of BxGa1-xAs deposited on GaAs substrate using MOCVD is discussed. In order to improve the sensitivity for B detection, a systematic study was undertaken using proton induced beam at three different energies (from 1.7, 2.4 and 3 MeV) with different tilting angles (0, 60° and 80°). Best conditions were found to be at 1.7 MeV and at 80° for proton energy and tilting angle within ten minutes of acquisition time.

International audience; Bonding of high purity polished copper was investigated using the Spark Plasma Sintering technique (SPS) showing the effect of SPS parameters (surface roughness, time, temperature and pressure) on the bonding strength behaviour. Mechanical characterization of the bonded samples was performed at room temperature using tensile test. Two surfaces roughnesses were studied (un-polished and polished samples). It was found that the bonding strength varied from 50 MPa to 233 MPa for un-polished and polished surfaces respectively The tensile strength of the used bulk copper-rod was found to be 365 MPa, while most results are over 122 MPa (a third of the bulk value).

1st Mediterranean Conference on Innovative Materials and Applications (CIMA 2011), Beirut, LEBANON, MAR 15-17, 2011; International audience; We report magnetotransport measurements in single epitaxial graphene layers grown on the C-face of an 8 degrees off-axis 4H-SiC substrate using high temperature annealing conditions with a graphite cap covering the sample. The graphene sheets were found p-type doped, with mobilities varying between 1000 and 11000 cm(2/)V.s from device to device at 1.6 K. We examine the signature of weak localization and universal conductance fluctuations at weak magnetic field and we show that the phase coherence lengths extracted from the two phenomena are in satisfactory agreement.