Effect of growth defects on microwave properties in epitaxial Ba0.5Sr0.5TiO3 thin films grown on (001) MgO by pulsed laser deposition

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Abstract

BaSrTiO (BSTO) films have been grown heteroepitaxially on (001) MgO substrates by pulsed laser deposition (PLD) to fabricate microwave phase shifters for the wide frequency range 45 MHz-50 GHz. Both as-grown and ex situ annealed films have a cube on cube epitaxial relationship with 〈100〉BSTO//〈100〉MgO. Threading dislocations are the dominant defects, mostly with Burgers vectors b = 〈101〉. Growth at 10 mbar oxygen pressure, compared to 10 mbar, resulted in significantly better properties. Ex situ annealing of the film grown at 0.1 mbar resulted in a reduction of 40% in threading dislocation density and a 40% increase in dielectric tunability.

Details

Original languageEnglish
Pages (from-to)2505-2518
Number of pages14
JournalPhilosophical Magazine
Volume88
Issue number16
Publication statusPublished - 1 Jun 2008