Fracture Dynamics during the Silicon Layer Transfer of the Smart Cut Process

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(Invited) Defect Evolution during Silicon Smartcut

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Finding applications for materials

SIGLEAvailable from British Library Document Supply Centre-DSC:9106.170(CUED/C-MATS/TR 255) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Kinetics and coupled dynamics of dewetting and chemical reaction in Si/SiO2/Si system

International audienceWe report on the observation of a coupling between the dewetting of a Si layer on SiO 2 induced by surface/interface energy minimization and the etching between both materials due to the Si+SiO 2 →2 SiO ↑ g reaction. In the limit of a thin SiO 2 layer (≤ 10 nm) sandwiched between a Si layer and a Si handle wafer, the front of Si dewetting and the front of SiO 2 etching coexist in a narrow region. The interplay between both phenomena gives rise to specific morphologies. We show that extended Si fingers formed by dewetting are stabilized with respect to Rayleigh Plateau type instability over tenth of microns thanks to a localized etching of the SiO 2 layer. The break up of this structure occurs abruptly by an unzipping process combining dewetting and etching phenomena. We also put in evidence that Si rings are created with a thin SiO 2 layer in the center. These processes are thermally activated with an activation energy of 2.4±0.5 eV and 4.0±0.5 eV respectively for dewetting and the etching reaction. All these results highlight the respective roles of wetting and etching in Si/SiO 2 /Si system dynamics and could be a stepping stone for the development of advanced processes based on Silicon-On-Insulator technology

Optimum design of metal foam in sandwich structures using genetic algorithm

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Effect of H-implantation in the local elastic properties of silicon crystals

International audienceIn contrast to previous reports, where the modification of elastic constants of semiconductors irradiated with heavy ions was related to crystalline to amorphous transition, here we show that hydrogen implantation causes a dramatic modification of the shear modulus of Si at relatively low levels of crystalline damage. To study the system, we developed an alternative and rather general method to determine the shear modulus of the buried implanted layer. We use elasticity theory to link two simple measurements: (i) the wafer curvature to extract the in-plane stresses and (ii) x-ray diffraction to determine strains in the implanted layer

Crack Front Interaction with Self-Emitted Acoustic Waves

International audienceThe interaction of a propagating crack in implanted silicon with self-emitted acoustic waves is studied and reveals the generation of periodic patterns on wafers surfaces after separation. The measurement and identification of the acoustic waves have been experimentally achieved showing the emergence of dominant shear waves acoustic frequencies related to the crack velocity. The surface modifications are made of roughness modulations at large scale due to periodic deviations of the crack front. A physical mechanism explaining the pattern formation is proposed accounting for the observed wavelengths

Edge Water Penetration in Direct Bonding Interface

International audienceWe report here on measurements demonstrating that water is able to enter a hydrophilic wafer bonding assembly from the edge. The driving forces for water entry are capillary forces driven by the negative Laplace pressure. The characteristic time for water to penetrate the interface is consistent with standard values for water viscosity and gap width