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41 results on '"Bäcke, Olof"'

13. Measuring residual stresses in individual on-chip interconnects using synchrotron nanodiffraction.

Author

Zhang, Yaqian, Du, Leiming, Bäcke, Olof, Kalbfleisch, Sebastian, Zhang, Guoqi, Vollebregt, Sten, and Hörnqvist Colliander, Magnus

Subjects
RESIDUAL stresses, THERMAL expansion, ELECTRODIFFUSION, INTEGRATED circuits, COPPER, SYNCHROTRONS
Abstract

As the dimensions of interconnects in integrated circuits continue to shrink, an urgent need arises to understand the physical mechanism associated with electromigration. Using x-ray nanodiffraction, we analyzed the stresses in Blech-structured pure Cu lines subjected to different electromigration conditions. The results suggest that the measured residual stresses in the early stages of electromigration are related to relaxation of stresses caused by thermal expansion mismatch, while a developing current-induced stress leads to reductions in the residual stress after longer test times. These findings not only validate the feasibility of measuring stress in copper lines using nanodiffraction but also highlight the need for a further understanding, particularly through in situ electromigration experiments with x-ray nanodiffraction analysis. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Chemical vapor deposition of TiN on transition metal substrates

Author

von Fieandt, Linus, Larsson, Tommy, Lindahl, Erik, Bäcke, Olof, and Boman, Mats

Subjects
Thermodynamic calculations, TiN, Alternate binder phase, Materials Chemistry, Materialkemi, CVD
Abstract

The growth of chemical vapor deposited TiN from a reaction gas mixture of TiCl4, N-2 and H-2 was investigated on three different transition metal substrates: Fe, Co and Ni at deposition temperatures ranging from 850 degrees C to 950 degrees C. The interactions between the substrate metals and the gas phase were investigated using thermodynamic calculations. The TiN coatings were characterized by scanning electron microscopy, scanning transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and transmission Kikuchi diffraction. Chemical vapor deposition (CVD) of TiN on Co substrates resulted in dense, columnar coatings of single phase TiN. The activation energy for TiN deposition on Co was determined to be 90 kJ/mol. CVD of TiN on Fe substrates caused severe substrate corrosion by the formation of gaseous FeClx. Due to the substrate corrosion, the activation energy could not be determined. Furthermore, it was found that CVD of TiN on Ni substrates produced a phase mixture of TiN and Ni3Ti. Formation of Ni3Ti could be minimized by decreasing the H-2 partial pressure and increasing the N-2 partial pressure. Deposition on Ni yielded two different activation energies, 40 kJ/mol in the temperature interval 850 degrees C to 900 degrees C and 165 kJ/mol in the interval 900 degrees C to 950 degrees C. This is an indication of two different types of process control, which were identified as Ni diffusion into the growing film and a gas phase processes. The results of the present study showed that CVD of TiN on a cemented carbide using Fe and Ni in the binder phase, must be optimized in order to avoid corrosion or unwanted phases. Methods to achieve this are presented in this paper.

Published
2018

26. Correction to “A New Tetracyclic Lactam Building Block for Thick, Broad-Bandgap Photovoltaics”

Author

Kroon, Renee, primary, Diaz de Zerio Mendaza, Amaia, additional, Himmelberger, Scott, additional, Bergqvist, Jonas, additional, Bäcke, Olof, additional, Faria, Gregório Couto, additional, Gao, Feng, additional, Obaid, Abdulmalik, additional, Zhuang, Wenliu, additional, Gedefaw, Desta, additional, Olsson, Eva, additional, Inganäs, Olle, additional, Salleo, Alberto, additional, Müller, Christian, additional, and Andersson, Mats R., additional

Published
2015
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29. A New Tetracyclic Lactam Building Block for Thick, Broad-Bandgap Photovoltaics

Author

Kroon, Renee, primary, Diaz de Zerio Mendaza, Amaia, additional, Himmelberger, Scott, additional, Bergqvist, Jonas, additional, Bäcke, Olof, additional, Faria, Gregório Couto, additional, Gao, Feng, additional, Obaid, Abdulmalik, additional, Zhuang, Wenliu, additional, Gedefaw, Desta, additional, Olsson, Eva, additional, Inganäs, Olle, additional, Salleo, Alberto, additional, Müller, Christian, additional, and Andersson, Mats R., additional

Published
2014
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31. Nanostructures: Fullerene Nucleating Agents: A Route Towards Thermally Stable Photovoltaic Blends (Adv. Energy Mater. 9/2014)

Author

Lindqvist, Camilla, primary, Bergqvist, Jonas, additional, Feng, Ching‐Chiao, additional, Gustafsson, Stefan, additional, Bäcke, Olof, additional, Treat, Neil D., additional, Bounioux, Céline, additional, Henriksson, Patrik, additional, Kroon, Renee, additional, Wang, Ergang, additional, Sanz‐Velasco, Anke, additional, Kristiansen, Per Magnus, additional, Stingelin, Natalie, additional, Olsson, Eva, additional, Inganäs, Olle, additional, Andersson, Mats R., additional, and Müller, Christian, additional

Published
2014
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33. Fullerene Nucleating Agents: A Route Towards Thermally Stable Photovoltaic Blends

Author

Lindqvist, Camilla, primary, Bergqvist, Jonas, additional, Feng, Ching‐Chiao, additional, Gustafsson, Stefan, additional, Bäcke, Olof, additional, Treat, Neil D., additional, Bounioux, Céline, additional, Henriksson, Patrik, additional, Kroon, Renee, additional, Wang, Ergang, additional, Sanz‐Velasco, Anke, additional, Kristiansen, Per Magnus, additional, Stingelin, Natalie, additional, Olsson, Eva, additional, Inganäs, Olle, additional, Andersson, Mats R., additional, and Müller, Christian, additional

Published
2014
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35. Sub-glass transition annealing enhances polymer solar cell performance

Author

Bergqvist, Jonas, primary, Lindqvist, Camilla, additional, Bäcke, Olof, additional, Ma, Zaifei, additional, Tang, Zheng, additional, Tress, Wolfgang, additional, Gustafsson, Stefan, additional, Wang, Ergang, additional, Olsson, Eva, additional, Andersson, Mats R., additional, Inganäs, Olle, additional, and Müller, Christian, additional

Published
2014
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39. Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study

Author

Amaia Diaz de Zerio Mendaza, Mats Andersson, Olof Bäcke, Camilla Lindqvist, Eva Olsson, Stefan Gustafsson, Ergang Wang, Christian Müller, Bäcke, Olof, Lindqvist, Camilla, Diaz de Zerio Mendaza, Amaia, Gustafsson, Stefan, Wang, Ergang, Andersson, Mats R, Mülller, Christian, and Olsson, Eva

Subjects
Materials science, Fullerene, Annealing (metallurgy), electron tomography, Nucleation, bulk heterojunction, Nanotechnology, law.invention, Condensed Matter::Materials Science, fullerene crystallization, Electron tomography, Nanocrystal, Chemical engineering, law, Physics::Atomic and Molecular Clusters, General Materials Science, photovoltaic blend, Crystallization, Thin film, Glass transition
Abstract

The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals,ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components. Refereed/Peer-reviewed

Published
2015

40. Neat C60:C70 buckminsterfullerene mixtures enhance polymer solar cell performance

Author

Jonas Bergqvist, Camilla Lindqvist, Olof Bäcke, Amaia Diaz de Zerio Mendaza, Mats Andersson, Olle Inganäs, Feng Gao, Eva Olsson, Christian Müller, Renee Kroon, Diaz De Zerio, Mendaza A, Bergqvist, Jonas, Bäcke, Olof, Lindqvist, Camilla, Kroon, Renee, Gao, Feng, Andersson, Mats R, Olsson, Eva, Inganäs, Olle, and Muller, Christian

Subjects
Nanostructure, Materials science, Fullerene, Renewable Energy, Sustainability and the Environment, polymer, Energy conversion efficiency, solar power, General Chemistry, Acceptor, Polymer solar cell, chemistry.chemical_compound, Buckminsterfullerene, chemistry, Chemical engineering, Polymer chemistry, voltage, General Materials Science, Quantum efficiency, Thin film
Abstract

Electronic supplementary information (ESI) available. See DOI: 10.1039/c4ta02515f We demonstrate that bulk-heterojunction blends based on neat, unsubstituted buckminsterfullerenes (C60, C70) and a thiophene–quinoxaline copolymer (TQ1) can be readily processed from solution. Atomic force and transmission electron microscopy as well as photoluminescence spectroscopy reveal that thin filmswith a fine-grained nanostructure can be spin-coated, which display a good photovoltaic performance. Replacement of substituted fullerenes with C60 or C70 only results in a small drop in open-circuit voltage from 0.9 V to about 0.8 V. Thus, a power conversion efficiency of up to 2.9% can be maintained if C70 is used as the acceptor material. Further improvement in photovoltaic performance to 3.6% is achieved, accompanied by a high internal quantum efficiency of 75%, if a 1 : 1 C60:C70 mixture is used as the acceptormaterial, due to its improved solubility in orthodichlorobenzene. Refereed/Peer-reviewed

Published
2014

41. High-Entropy Mixtures of Pristine Fullerenes for Solution-Processed Transistors and Solar Cells.

Author

Mendaza AD, Melianas A, Rossbauer S, Bäcke O, Nordstierna L, Erhart P, Olsson E, Anthopoulos TD, Inganäs O, and Müller C

Abstract

The solubility of pristine fullerenes can be enhanced by mixing C60 and C70 due to the associated increase in configurational entropy. This "entropic dissolution" allows the preparation of field-effect transistors with an electron mobility of 1 cm(2) V(-1) s(-1) and polymer solar cells with a highly reproducible power-conversion efficiency of 6%, as well as a thermally stable active layer., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2015
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