Ferroelectric and dielectric study of strontium tantalum based perovskite oxynitride films deposited by reactive rf magnetron sputtering

• Published in: Materials research bulletin Vol. 96; no. Part 2; pp. 126 - 132
• Main Authors: Le Paven, C., Benzerga, R., Ferri, A., Fasquelle, D., Laur, V., Le Gendre, L., Marlec, F., Tessier, F., Cheviré, F., Desfeux, R., Saitzek, S., Castel, X., Sharaiha, A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.12.2017; Elsevier
• Series: The 9th international conference on the Microwave Materials and Their Applications
• Subjects: Chemical Sciences; Condensed Matter; DEPOSITION; DEPOSITS; EPITAXY; FERROELECTRIC MATERIALS; Ferroelectricity; KHZ RANGE; MAGNESIUM OXIDES; MAGNETRONS; Material chemistry; MATERIALS SCIENCE; NITRIDES; Oxynitride; PERMITTIVITY; PEROVSKITE; Physics; Reactive sputtering; SPUTTERING; STRONTIUM; SUBSTRATES; TANTALUM; THIN FILMS; Thin films; Perovskite; Ferroelectricity; Epitaxy; Reactive sputtering; Permittivity; Oxynitride
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2016.11.030

[Display omitted] •Oxynitride perovskite thin films were deposited by reactive sputtering.•Films are textured or epitaxially grown on MgO and Nb-SrTiO3 substrates.•Local piezoelectric and ferroelectric behavior was highlighted by PFM.•A 1600nm-thick film presents a permittivity of 175 at 10kHz and RT.•Permittivity is around 65 in high frequency range. Strontium and tantalum based oxynitride perovskite thin films were deposited by reactive magnetron sputtering. Epitaxial films deposited on Nb-SrTiO3 substrates show smooth surfaces with roughness values from 1.5 to 3.6nm for a thickness of films in the range 20–1600nm. The samples are yellow with band gap values around 2.35eV. Piezo-force microscopy characterization pointed out the local piezoelectric and ferroelectric behavior of the oxynitride perovskite films. In the low frequency range, the 1600nm-thick film exhibits a permittivity of 175 at 10kHz, with dielectric losses of 0.055. Permittivity is lowered in high frequencies with a value around 65 obtained on a 1520nm-thick film deposited on MgO substrate, which is textured with a preferential c-axis orientation. No accordability of the permittivity was highlighted at a macroscopic scale. The moderate crystallographic strain evidenced in the 20nm thin film does not induce a high permittivity.