Cho, K.-H. Kang, C.-Y. Yoon, S.-J. Kim, H.-J. 2024-01-21T01:00:16Z 2024-01-21T01:00:16Z 2021-09-02 2007-07 1225-0562 https://pubs.kist.re.kr/handle/201004/134288 The dielectric properties of (Ba0.5 Sr0.5)TiO3 ferroelectric thin films have been investigated according to the substrates in order to optimize the their properties. MgO, r-plane sapphire, and poly-crystalline sapphire (Alumina) substrates have been used to deposite (Ba0.5 Sr0.5)TiO3 ferroelectric thin films by RF magnetron sputtering. The BST thin films deposited on the single crystal (100)MgO substrates have high tunability and low dielectric loss. These results are caused by a low misfit between the lattice parameters of the BST films and the substrate. The BST films deposited on r-plane sapphire have relatively high misfit, and the tunability of 17% and dielectric loss of 0.0007. To improve the dielectric properties of the BST films, the post-annealing methods has been introduced. The BST films deposited on (100)MgO, (1102)r-plane sapphire, and poly-crystalline sapphire substrates have best properties in post-annealing conditions of 1050°C, 1100°C, and 1150°C, respectively. The different optimal post-annealing conditions have been found according to the different misfits between the films and substrates, and thermal expansion coefficients. Moreover, the films deposited on alumina substrate which is relatively cheap have a good tunability properties of 23% by the post-annealing. Korean Materials Research Society of Korea Microwave properties and microstructures of (Ba,Sr)TiO3 thin films on various substrates with annealing temperature Article 10.3740/MRSK.2007.17.7.386 1 Korean Journal of Materials Research, v.17, no.7, pp.386 - 389 Korean Journal of Materials Research 17 7 386 389 scopus kci ART001083099 2-s2.0-34548037253 Article BST Ferroelectric Microwave tunable devices Thin film