Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Porous thin films considered for applications like separation, sensing and microelectronic have to sustain mechanical stresses during their integration process or in working conditions. Thanks to recent progress in processing methods, it is now possible to precisely control the porosity and combine ordered mesopores with randomly-distributed macropores to achieve hierarchically porous materials. The mechanical properties of thin films containing different types of porosity (ordered meso, random macro and hierarchical) have been investigated by means of nanoindentation. In particular a method recently proposed by Li and Vlassak (H. Li, J.J. Vlassak, Journal of Materials Research 24 (2009) 1114-1126) is applied to account for the substrate effect. Residual indent impressions were imaged by Atomic Force Microscopy (AFM) to provide some insights in the mechanical behavior of the films. In addition, experimental indentation moduli are compared to theoretical predictions obtained via Finite Element (FE) analysis. The different porous structures have been modeled by FE to obtain the effective elastic properties from which the indentation modulus can be inferred. Finally, the experimental-model differences are discussed. © 2010 Elsevier Inc. All rights reserved.
ISSN: 1387-1811

hal-01683194
https://hal.univ-antilles.fr/hal-01683194
DOI : 10.1016/j.micromeso.2010.09.004

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
XFILM is a computer program for determining the thickness and composition of thin films on Substrates and multilayers by electron probe microanalysis. In this study, we describe the X-ray emission model implemented in the latest version of XFILM and assess its reliability by comparing measured and calculated k-ratios from thin-film samples available in the literature. We present and discuss examples of applications of XFILM that illustrate the capabilities of the program.
ISSN: 1431-9276

hal-00475542
https://hal.archives-ouvertes.fr/hal-00475542
DOI : 10.1017/S1431927609991218

Éditeur(s) : HAL CCSD Institute of Electrical and Electronics Engineers (IEEE) Institute of Electrical and Electronics Engineers
Résumé : International audience
Conventional quantitative electron probe microanalysis of actinides requires the use of reference standard samples. However, for such elements, standards are generally not available. To overcome this difficulty, standardless methods of analysis are used, in which the x-ray intensity emitted by the standard is calculated. To be reliable, such calculations require accurate knowledge of physical data such as the x-ray production cross section. However, experimental data of this quantity are not always available for actinide elements. In the present work, experimental L and M x-ray production cross sections were measured for elements uranium and lead. Measurements were performed with two electron microprobes using wavelength-dispersive spectrometers using thin self-supporting targets. Experimental results are compared with calculated cross sections obtained from different analytical formulae, and, whenever possible, with experimental data obtained from the literature.
ISSN: 0018-9499

hal-01122820
https://hal.archives-ouvertes.fr/hal-01122820
DOI : 10.1109/TNS.2014.2321016

Éditeur(s) : HAL CCSD American Institute of Physics
Résumé : International audience
Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10Hz, and 30mJ/cm2). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation.Atomic Force Microscopy (AFM) analyses have shown the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phaseduring the LIPSS formation in the picosecond regime. VC 2015 AIP Publishing LLC
ISSN: 0003-6951

hal-01226065
https://hal.archives-ouvertes.fr/hal-01226065
DOI : 10.1063/1.4935413