abstract
The perovskite phase nucleation and growth of Ba0.8Sr0.2TiO3 [BST(80/20)] films was restricted to the bottom interface by the use of a Ba0.8Sr0.2TiO3 [BST(80/20)] sol-gel seed layer of optimized thickness. As a result (h00) preferred orientation, BST thin films on Pt/Ti/SiO2/Si with enhanced electric properties were prepared by sol-gel at considerably low temperatures (700 degrees C). The effect of sol-gel seed layers and their thickness on the structure/ microstructure and electric properties of BST sol-gel derived films was evaluated in this study. 400-nm-thick BST films with a 30-nm-thick seed layer showed a maximized (h00) preferred orientation growth with a grain size of 120 nm. The dielectric constant varied from 300 to 830 at 1 kHz and from 230 to 580 at 1 MHz for films without a seed layer and with a 30-nm-thick seed layer, respectively. In addition the tunability of the dielectric constant was improved to similar to 37% at 150 kV/cm, compared with that without seed layer. The remanant polarization and leakage current of BST films with an optimal seed layer were 1.6 mu C/cm(2) with a coercive field of 30 kV/cm and 8.0 x 10(-7) A/cm(2) up to an applied electric field of 167.5 kV/cm, respectively. The electrical performance of these BST films is discussed in relation to the effect of the seed layer thickness on the texture and microstructure of the films.
keywords
TUNABLE MICROWAVE APPLICATIONS; SOLUTION-DEPOSITED BATIO3; DIELECTRIC-PROPERTIES; MICROSTRUCTURE; TUNABILITY; SRTIO3; ORIENTATION; CAPACITORS
subject category
Chemistry; Materials Science
authors
Fu, Z; Wu, AY; Vilarinho, PM
our authors
