• search hit 1 of 1
Back to Result List

Unveiling the complex electronic structure of amorphous metal oxides

  • Amorphous materials represent a large and important emerging area of material's science. Amorphous oxides are key technological oxides in applications such as a gate dielectric in Complementary metal-oxide semiconductor devices and in Silicon-Oxide-Nitride-Oxide-Silicon and TANOS (TaN-Al2O3-Si3N4-SiO2-Silicon) flash memories. These technologies are required for the high packing density of today's integrated circuits. Therefore the investigation of defect states in these structures is crucial. In this work we present X-ray synchrotron measurements, with an energy resolution which is about 5-10 times higher than is attainable with standard spectrometers, of amorphous alumina. We demonstrate that our experimental results are in agreement with calculated spectra of amorphous alumina which we have generated by stochastic quenching. This first principles method, which we have recently developed, is found to be superior to molecular dynamics in simulating the rapid gas to solid transition that takes place as this material is deposited forAmorphous materials represent a large and important emerging area of material's science. Amorphous oxides are key technological oxides in applications such as a gate dielectric in Complementary metal-oxide semiconductor devices and in Silicon-Oxide-Nitride-Oxide-Silicon and TANOS (TaN-Al2O3-Si3N4-SiO2-Silicon) flash memories. These technologies are required for the high packing density of today's integrated circuits. Therefore the investigation of defect states in these structures is crucial. In this work we present X-ray synchrotron measurements, with an energy resolution which is about 5-10 times higher than is attainable with standard spectrometers, of amorphous alumina. We demonstrate that our experimental results are in agreement with calculated spectra of amorphous alumina which we have generated by stochastic quenching. This first principles method, which we have recently developed, is found to be superior to molecular dynamics in simulating the rapid gas to solid transition that takes place as this material is deposited for thin film applications. We detect and analyze in detail states in the band gap that originate from oxygen pairs. Similar states were previously found in amorphous alumina by other spectroscopic methods and were assigned to oxygen vacancies claimed to act mutually as electron and hole traps. The oxygen pairs which we probe in this work act as hole traps only and will influence the information retention in electronic devices. In amorphous silica oxygen pairs have already been found, thus they may be a feature which is characteristic also of other amorphous metal oxides.show moreshow less

Export metadata

Additional Services

Share in Twitter Search Google Scholar Statistics
Metadaten
Author:C. Arhammar, Annette Pietzsch, Nicolas Bock, Erik Holmstroem, C. Moyses Araujo, Johan Grasjo, Shuxi Zhao, Sara Green, T. Peery, Franz Hennies, Shahrad Amerioun, Alexander Foehlisch, Justine Schlappa, Thorsten Schmitt, Vladimir N. Strocov, Gunnar A. Niklasson, Duane C. Wallace, Jan-Erik Rubensson, Borje Johansson, Rajeev Ahuja
DOI:https://doi.org/10.1073/pnas.1019698108
ISSN:0027-8424 (print)
Parent Title (English):Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Acad. of Sciences
Place of publication:Washington
Document Type:Article
Language:English
Year of first Publication:2011
Year of Completion:2011
Release Date:2017/03/26
Tag:X-ray absorption spectroscopy; ab initio; coating; stochastic quench
Volume:108
Issue:16
Pagenumber:6
First Page:6355
Last Page:6360
Funder:Swedish Research Council; Sandvik Tooling; Fondo Nacional de Desarrollo Cientifico y Tecnologico (FONDECYT) [1110602]; Europeean Community [FP7/2007-2013, 226716]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
Peer Review:Referiert