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A Pereira - One of the best experts on this subject based on the ideXlab platform.

  • rare earth doped micro emitters made by lift off processing in pulsed laser deposited layers on si substrate
    Optics Express, 2021
    Co-Authors: Alban Gassenq, Etienne Cleyetmerle, Hoshang Sahib, Bruno Baguenard, Ali Belarouci, Regis Orobtchouk, Frederic Lerouge, S Guy, A Pereira
    Abstract:

    Rare earth emitters are promising in integrated optics but require complex integration on silicon. In this work, we have fabricated an Y2O3:Eu3+ micro-emitter on SiO2 on Si substrate without etching. Since pulsed laser deposition produces a high Quality layer at room temperature, material can be locally deposited on top of substrates by lift-off processing. After annealing, microstructures exhibit good Crystallographic Quality with controlled dimensions for light confinement and narrow emission. This works allows envisioning rare-earth doped micro-photonic structures directly integrated on silicon without etching, which opens the way to integration of new functional materials on silicon platform.

Hideo Miura - One of the best experts on this subject based on the ideXlab platform.

  • effect of Crystallographic Quality of grain boundaries on both mechanical and electrical properties of electroplated copper thin film interconnections
    Journal of Electronic Packaging, 2015
    Co-Authors: Naokazu Murata, Ken Suzuki, Naoki Saito, Kinji Tamakawa, Hideo Miura
    Abstract:

    Effects of Crystallographic Quality of grain boundaries on mechanical and electrical properties were investigated experimentally. A novel method using two parameters of image Quality (IQ) and confidence index (CI) values based on electron back-scattering diffraction (EBSD) analysis was proposed in order to evaluate Crystallographic Quality of grain boundaries. IQ value was defined as an index to evaluate crystallinity in region irradiated with electron beam. CI value determined existence of grain boundaries in the region. It was found that brittle intergranular fatigue fracture occurred in the film without annealing and the film annealed at 200 °C because network of grain boundaries with low crystallinity remained in these films. On the other hand, the film annealed at 400 °C caused only ductile transgranular fatigue fracture because grain boundaries with low crystallinity almost disappeared. From results of measurement of electrical properties, electrical resistivity of copper interconnection annealed at 400 °C with high crystallinity (2.09 × 10−8 Ωm) was low and electron migration (EM) resistance was high compared with an copper interconnection without annealing with low crystallinity (3.33 × 10−8 Ωm). It was clarified that the interconnection with high crystallinity had superior electrical properties. Thus, it was clarified that the Crystallographic Quality of grain boundaries has a strong correlation of mechanical and electrical reliability.

  • Evaluation of the Crystallographic Quality of Electroplated Copper Thin-Film Interconnection Embedded in a Si Substrate
    Volume 1: Advanced Packaging; Emerging Technologies; Modeling and Simulation; Multi-Physics Based Reliability; MEMS and NEMS; Materials and Processes, 2013
    Co-Authors: Ryosuke Furuya, Ken Suzuki, Osamu Asai, Chuanhong Fan, Hideo Miura
    Abstract:

    Electroplated copper thin films have started to be applied to the interconnection material in TSV structures because of its low electric resistivity and high thermal conductivity. However, the electrical resistivity of the electroplated copper thin films surrounded by SiO2 was found to vary drastically comparing with those of the conventional bulk material. This was because that the electroplated copper thin films consisted of grains with low crystallinity and grain boundaries with high defect density. Thus, in this study, both the crystallinity and electrical properties of the electroplated copper thin films embedded in the TSV structure was evaluated quantitatively by changing the electroplating conditions and thermal history after the electroplating. It was observed that many voids and hillocks appeared in the TSV structures after the high temperature annealing which was introduced for improving the crystallinity of the electroplated films. Therefore, it is very important to evaluate the Crystallographic Quality of the electroplated copper thin films after electroplating to assure both the mechanical and electrical properties of the films.Copyright © 2013 by ASME

  • Improvement of Crystallographic Quality of Electroplated Copper Thin-Film Interconnections for Through-Silicon Vias
    Japanese Journal of Applied Physics, 2013
    Co-Authors: Ken Suzuki, Ryosuke Furuya, Naokazu Murata, Naoki Saito, Osamu Asai, Hideo Miura
    Abstract:

    The relationship between the electrical properties and Crystallographic Quality (crystallinity) of electroplated copper thin-film interconnections was investigated. The crystallinity of the grains and grain boundaries of the interconnections was evaluated on the basis of the image Quality (IQ) value obtained by electron back-scatter diffraction (EBSD) analysis. The electrical properties of the interconnections vary markedly depending on their crystallinity. The crystallinity also changed markedly as functions of electroplating conditions and the annealing temperature after electroplating. Although the electro migration (EM) resistance of the annealed interconnection was improved, stress-induced migration (SM) was activated by a high residual stress after annealing. To improve electrical reliability without heat treatment after electroplating, the effects of the seed layer under the interconnections on the crystallinity were investigated. As a result, the crystallinity was improved by changing the seed layer from Cu to Ru. In addition, the decrease in current density during electroplating also improved the crystallinity. Therefore, both introducing the Ru seed layer and decreasing the current density during electroplating are effective for developing highly reliable copper interconnections.

  • Evaluation of the Crystallographic Quality of electroplated copper thin-film interconnections embedded in TSV structures
    2012 14th International Conference on Electronic Materials and Packaging (EMAP), 2012
    Co-Authors: Ryosuke Furuya, Ken Suzuki, Hideo Miura
    Abstract:

    Electroplated copper thin films have started to be applied to the Through Silicon Via (TSV) interconnections. Unfortunately, however, the electrical resistivity of the electroplated copper thin films was found to vary drastically comparing with those of the conventional bulk copper. This was because that the films consisted of grains with low Crystallographic Quality and a lot of porous grain boundaries. In this study, the electroplated copper thin film interconnections were embedded in a silicon substrate to model the TSV structure. It was observed that many voids and hillocks appeared on the surface of the films after annealed at 400°C. In addition, it was also found that the electrical resistivity of the films without annealing was much higher than that of bulk copper. As a result, it is very important to evaluate the Crystallographic Quality of the electroplated copper thin films after electroplated to assure the long-term reliability.

  • effect of Crystallographic Quality of grain boundaries on both mechanical and electrical properties of electroplated copper thin film interconnections
    ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems MEMS and NEMS: Volume 2, 2011
    Co-Authors: Naokazu Murata, Ken Suzuki, Naoki Saito, Kinji Tamakawa, Hideo Miura
    Abstract:

    Both mechanical and electronic properties of electroplated copper films used for interconnections were investigated experimentally considering the change of their micro texture caused by heat treatment. The fracture strain of the film annealed at 400°C increased from about 3% to 15% and their yield stress decreased from about 270 MPa to 90 MPa. In addition, it was found that two different fatigue fracture modes appeared in the film. One was a typical ductile fracture mode and the other was brittle one. When the brittle fracture occurred, a crack propagated along weak or porous grain boundaries which were formed during electroplating. The brittle fracture mode disappeared after the annealing at 300°C. These results clearly indicated that the mechanical properties of electroplated copper thin films vary drastically depending on their micro texture. The electrical reliability of the electroplated copper yjin film interconnections was also investigated. The interconnections used for electromigration tests were made using by a damascene process. An abrupt fracture mode due to local fusion appeared in the as-electroplated interconnections. Since the fracture rate increased almost linearly with the square of the applied current density, this fracture mode was dominated by local Joule heating. It seemed that the local current concentration occurred around the porous grain boundaries. The life of the interconnections was improved drastically after the annealing at 400°C. This was because of the increase of the average grain size and the improvement of the Quality of grain boundaries in the annealed interconnections. However, the stress-induced migration occurred in the interconnections annealed at 400°C. This was because of the high tensile residual stress caused by the constraint of the densification of the films during annealing by the surrounding oxide film. Therefore, it is very important to control the Crystallographic Quality of electroplated copper films for improving the reliability of thin film interconnections. The Quality of the grain boundaries can be evaluated by applying an EBSD (Electron Back Scatter Diffraction) analysis. New two experimentally determined parameters are proposed for evaluating the Quality of grain boundaries quantitatively. It was confirmed that the Crystallographic Quality of grain boundaries can be evaluated quantitatively by using the two parameters, and it is possible to estimate both the strength and reliability of the interconnections.Copyright © 2011 by ASME

James S Speck - One of the best experts on this subject based on the ideXlab platform.

  • strain compensated superlattices on m plane gallium nitride by ammonia molecular beam epitaxy
    Journal of Applied Physics, 2017
    Co-Authors: Micha N Fireman, Bastien Bonef, Erin C Young, Nishant Nookala, Mikhail A Belkin, James S Speck
    Abstract:

    The results of tensile strained AlN/GaN, AlGaN/GaN, and compressive strained InGaN/GaN superlattices (SLs) grown by Ammonia MBE (NH3-MBE) are presented. A combination of atom probe tomography and high-resolution X-ray diffraction confirms that periodic heterostructures of high Crystallographic Quality are achieved. Strain induced misfit dislocations (MDs), however, are revealed by cathodoluminescence (CL) of the strained AlN/GaN, AlGaN/GaN, and InGaN/GaN structures. MDs in the active region of a device are a severe problem as they act as non-radiative charge recombination centers, affecting the reliability and efficiency of the device. Strain compensated SL structures are subsequently developed, composed of alternating layers of tensile strained AlGaN and compressively strained InGaN. CL reveals the absence of MDs in such structures, demonstrating that strain compensation offers a viable route towards MD free active regions in III-Nitride SL based devices.The results of tensile strained AlN/GaN, AlGaN/GaN, and compressive strained InGaN/GaN superlattices (SLs) grown by Ammonia MBE (NH3-MBE) are presented. A combination of atom probe tomography and high-resolution X-ray diffraction confirms that periodic heterostructures of high Crystallographic Quality are achieved. Strain induced misfit dislocations (MDs), however, are revealed by cathodoluminescence (CL) of the strained AlN/GaN, AlGaN/GaN, and InGaN/GaN structures. MDs in the active region of a device are a severe problem as they act as non-radiative charge recombination centers, affecting the reliability and efficiency of the device. Strain compensated SL structures are subsequently developed, composed of alternating layers of tensile strained AlGaN and compressively strained InGaN. CL reveals the absence of MDs in such structures, demonstrating that strain compensation offers a viable route towards MD free active regions in III-Nitride SL based devices.

  • strain compensated superlattices on m plane gallium nitride by ammonia molecular beam epitaxy
    Journal of Applied Physics, 2017
    Co-Authors: Micha N Fireman, Bastien Bonef, Erin C Young, Nishant Nookala, Mikhail A Belkin, James S Speck
    Abstract:

    The results of tensile strained AlN/GaN, AlGaN/GaN, and compressive strained InGaN/GaN superlattices (SLs) grown by Ammonia MBE (NH3-MBE) are presented. A combination of atom probe tomography and high-resolution X-ray diffraction confirms that periodic heterostructures of high Crystallographic Quality are achieved. Strain induced misfit dislocations (MDs), however, are revealed by cathodoluminescence (CL) of the strained AlN/GaN, AlGaN/GaN, and InGaN/GaN structures. MDs in the active region of a device are a severe problem as they act as non-radiative charge recombination centers, affecting the reliability and efficiency of the device. Strain compensated SL structures are subsequently developed, composed of alternating layers of tensile strained AlGaN and compressively strained InGaN. CL reveals the absence of MDs in such structures, demonstrating that strain compensation offers a viable route towards MD free active regions in III-Nitride SL based devices.

Alban Gassenq - One of the best experts on this subject based on the ideXlab platform.

  • rare earth doped micro emitters made by lift off processing in pulsed laser deposited layers on si substrate
    Optics Express, 2021
    Co-Authors: Alban Gassenq, Etienne Cleyetmerle, Hoshang Sahib, Bruno Baguenard, Ali Belarouci, Regis Orobtchouk, Frederic Lerouge, S Guy, A Pereira
    Abstract:

    Rare earth emitters are promising in integrated optics but require complex integration on silicon. In this work, we have fabricated an Y2O3:Eu3+ micro-emitter on SiO2 on Si substrate without etching. Since pulsed laser deposition produces a high Quality layer at room temperature, material can be locally deposited on top of substrates by lift-off processing. After annealing, microstructures exhibit good Crystallographic Quality with controlled dimensions for light confinement and narrow emission. This works allows envisioning rare-earth doped micro-photonic structures directly integrated on silicon without etching, which opens the way to integration of new functional materials on silicon platform.

X Maeder - One of the best experts on this subject based on the ideXlab platform.

  • thin silicon films synthesis by aic on ono coated metal foils
    Energy Procedia, 2010
    Co-Authors: P Prathap, A Slaoui, X Maeder
    Abstract:

    Abstract Thin film crystalline silicon solar cells on flexible metallic substrates are being considered to be potential for low cost production. In the present investigation, metallic substrates (MS) coated with dielectric diffusion barrier layer (BL) of ONO (SiO 2 /SiN/SiO 2 ) have been used for the fabrication of polycrystalline silicon ( pc -Si) thin films using aluminium induced crystallisation (AIC) for the first time. The Crystallographic Quality of pc -Si layers synthesised by AIC has been studied using Raman and UV reflection spectroscopy. Similarly, grain size and defect distribution were characterised using electron backscattered diffraction (EBSD) analysis. The AIC grown films showed a symmetric peak around 519–520 cm −1 with an average grain size of 8.1 μm. The thermal stability of the diffusion barrier has been evaluated by annealing the structure, MS/BL/ pc -Si, at higher temperatures with subsequent chemical analysis of AIC grown pc -Si template. The potential impurities are identified to be Fe and Ni on a limited area. These results open the potential of fabrication of large grain silicon seed layer on flexible substrates for thin film solar cells technology.

  • thin silicon films synthesis by aic on ono coated metal foils
    European Material Research Society (E-MRS) Spring Conference Symposium on Inorganic and Nanostructured Photovoltaics, 2009
    Co-Authors: P Prathap, A Slaoui, X Maeder
    Abstract:

    Thin film crystalline silicon solar cells on flexible metallic substrates are being considered to be potential for low cost production. In the present investigation, metallic substrates (MS) coated with dielectric diffusion barrier layer (BL) of ONO (SiO2/SiN/SiO2) have been used for the fabrication of polycrystalline silicon (pc-Si) thin films using aluminium induced crystallisation (AIC) for the first time. The Crystallographic Quality of pc-Si layers synthesised by AIC has been studied using Raman and UV reflection spectroscopy. Similarly, grain size and defect distribution were characterised using electron backscattered diffraction (EBSD) analysis. The AIC grown films showed a symmetric peak around 519-520 cm with an average grain size of 8.1 μm. The thermal stability of the diffusion barrier has been evaluated by annealing the structure, MS/BL/pc-Si, at higher temperatures with subsequent chemical analysis of AIC grown pc-Si template. The potential impurities are identified to be Fe and Ni on a limited area. These results open the potential of fabrication of large grain silicon seed layer on flexible substrates for thin film solar cells technology. © 2010 Elsevier B.V. All rights reserved