Metastable YAlN and ScAlN thin films: growth and characterization
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
ScxAl1-xN and YxAl1-xN thin films were deposited in a ultra high vacuum system using reactive magnetron co-sputtering from elemental Al, Sc and Y targets in Ar/N2. Their mechanical, electrical, optical, and piezoelectrical properties were investigated with the help of transmission electron microscopy, xray diffraction, ellipsometry, I-V and C-V measurements, and two different techniques for piezoelectric characterization: piezoresponse force microscopy and double beam interferometry. Compared to AlN, improved electromechanical coupling and increase in piezoelectric response was found in ScxAl1-xN/TiN/Al2O3 structures with Sc content up to x=0.2. Microstructure of the films had a stronger influence on piezoelectric properties than the crystalline quality, which affected the leakage currents. YxAl1-xN thin films show a formation of solid solution up to x=0.22. Lattice constants obtained experimentally are in good agreement with theoretical predictions obtained through first principle (ab initio) calculations using density-functional formalism. The mixing enthalpy for wurtzite, cubic, and layered hexagonal phases of the YxAl1-xN system was also calculated.
Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. , 46 p.
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1524
IdentifiersURN: urn:nbn:se:liu:diva-76474DOI: 10.3384/lic.diva-76474Local ID: LIU-TEK-LIC-2012:9ISBN: 978-91-7519-934-4OAI: oai:DiVA.org:liu-76474DiVA: diva2:514730
Hultman, Lars, ProfessorBirch, Jens, ProfessorLloyd Spetz, Anita, Professor
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