Effect of Interlayer Thickness on Stress and Dielectric Properties of MgTiO3 Modified (Ba,Sr)TiO3 Multilayer Thin Films
Ba0.6Sr0.4TiO3 (BST)/MgTiO3 (MT)/ Ba0.6Sr0.4TiO3 multilayer thin films were deposited on LaNiO3 (100)/Pt/Ti/SiO2/Si (100) substrates by pulsed laser deposition. It was found that the film orientation and dielectric properties of BST/MT/BST multilayer thin films are strongly dependent on MT interlayer thickness. Pure BST thin film exhibits a (100) preferred orientation, while BST thin films with a MT interlayer exhibit a random orientation. Residual stress is relaxed dramatically due to a closer match of thermal expansion coefficients between the BST and MT interlayers. The largest figure of merit of 18.7 is achieved in the multilayer thin film with a 50-nm-thick MT interlayer, which exhibits a tunability of 30% and a lost tangent of 0.016. Dielectric constant and loss tangent decrease with increasing MT interlayer thickness due to a series dielectric dilution effect.
Jian-Feng Nie and Allan Morton
S. B. Lu and Z. K. Xu, "Effect of Interlayer Thickness on Stress and Dielectric Properties of MgTiO3 Modified (Ba,Sr)TiO3 Multilayer Thin Films", Materials Science Forum, Vols. 654-656, pp. 1796-1799, 2010