Structural features and microwave properties of Ba0.5Sr 0.5TiO3 films grown on sapphire substrates

Kwang Hwan Cho, Jong Yoon Ha, Chong Yun Kang, Ji Won Choi, Young Pak Lee, Seok Jin Yoon

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The change in dielectric constant of ferroelectric materials as a function of electric field is the key to wide range of microwave application such as tunable filter, impedance matching network, and phase shifter, In this study, ferroelectric Ba0.5Sr0.5TiO3 (BST) films were grown on r-cut sapphire and polycrystalline sapphire (poly-sapphire) substrates by RF sputtering. The results of comprehensive structural diagnostics of the films are correlated with the dielectric constant and dielectric loss of a co-planar BST varactor, measured at a frequency range of 1-3 GHz. Textured BST films approximately 500 nm thick, grown on r-cut sapphire substrates, are characterized by high dielectric constant ≥ 650. However, polycrystalline BST films, grown on poly-sapphire substrates, are less strained, having dielectric constant range of 430-640.

Original languageEnglish
Title of host publicationAdvances in Nanomaterials and Processing - IUMRS - ICA - 2006 International Conference in Asia
PublisherTrans Tech Publications Ltd
Number of pages4
EditionPART 2
ISBN (Print)3908451310, 9783908451310
Publication statusPublished - 2007
EventIUMRS International Conference in Asia 2006, IUMRS-ICA 2006 - Jeju, Korea, Republic of
Duration: 2006 Sept 102006 Sept 14

Publication series

NameSolid State Phenomena
NumberPART 2
ISSN (Print)1012-0394


OtherIUMRS International Conference in Asia 2006, IUMRS-ICA 2006
Country/TerritoryKorea, Republic of


  • Ferroelectric thin film
  • Tunable microwave device

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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