Growth of (Sr,La)-(Ta,Ti)-O-N perovskite oxide and oxynitride films by radio frequency magnetron sputtering: Influence of the reactive atmosphere on the film structure

• Published in: Journal of crystal growth Vol. 413; pp. 5 - 11
• Main Authors: Le Paven, C., Le Gendre, L., Benzerga, R., Cheviré, F., Tessier, F., Jacq, S., Traoré-Mantion, S., Sharaiha, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2015; Elsevier
• Subjects: Chemical Sciences; Curie temperature; Dielectric materials; Epitaxial growth; Ferroelectric materials; Ferroelectricity; Magnetron sputtering; Material chemistry; Nitrides; Oxides; Oxynitrides; Perovskites; Physical vapor deposition processes; Searching; X-ray diffraction; X-ray diffraction; Nitrides; Oxides; Physical vapor deposition processes; Perovskites; Dielectric materials
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2014.12.001

In the search for new dielectric and ferroelectric compounds, we were interested in the perovskite (Sr1-xLax)2(Ta1-xTix)2O7 solid solution with ferroelectric end members Sr2Ta2O7 (TCurie=−107°C) and La2Ti2O7 (TCurie=1461°C). In order to achieve a Curie temperature close to room temperature, the formulation with x=0.01 was chosen and synthetized as thin films by reactive radio-frequency magnetron sputtering. In oxygen rich plasma, a (Sr0.99La0.01)2(Ta0.99Ti0.01)2O7 film is deposited, characterized by a band-gap Eg=4.75eV and an (110) epitaxial growth on (001)MgO substrate. The use of nitrogen rich plasma allows to synthesize (Sr0.99La0.01)(Ta0.99Ti0.01)O2N oxynitride films, with band gap Eg~2.10eV and a polycrystalline, textured or epitaxial growth on (001)MgO substrate. Nitrogen-substoichiometric oxynitride films with larger lattice cells are produced for low dinitrogen percentages in the sputtering plasma. •Oxide and oxynitride films were deposited by reactive RF magnetron sputtering.•(Sr0.99La0.01)2(Ta0.99Ti0.01)2O7 film is (110) epitaxially grown on MgO substrate.•(Sr0.99La0.01)(Ta0.99Ti0.01)O2N films are preferentially (001) oriented on MgO substrate.•Nitrogen-substoichiometric films are deposited with low dinitrogen content in plasma.