Dielectric Enhancement Effect in (Ba_(0.7)Sr_(0.3)TiO_3/Ba_(0.5)Sr_(0.5)TiO_3)_n (n = 1,2,3,4) Multilayered Thin Films Deposited by Chemical Solution Deposition Method

摘要

Multilayered Ba_(0.7)Sr_(0.3)TiO_3/Ba_(0.5)Sr_(0.5)TiO_3 (BST0.7/0.5)_n (n = 1, 2, 3 and 4, respectively) thin films with different layered periods are prepared on Pt/TiO_2/SiO_2/Si substrates by chemical solution deposition method. The microstructure and dielectric properties of the films are investigated systematically. Obvious dielectric enhancement occurs in (BSTO.7/0.5),, multilayer comparing with Ba_(0.5)Sr_(0.5)TiO_3 and Ba_(0.7)Sr_(0.3)TiO_3 monolay-ered thin films due to Maxwell-Wagner effect. On the other hand, strain and grain sizes of the multilayered thin films can also affect the dielectric properties. Specially, the (BST0.7/0.5)2 shows the best dielectric properties with dielectric constant of 557, loss tangent of 0.025 and tunability of 46% at 200 KHz, which is beneficial in applications.