Effect of TiO₂ anatase layer on the microstructure and dielectric properties of (Ba_0.6Sr_0.4) TiO₃ films prepared by pulsed laser deposition

The effect of TiO₂ buffer layers on the microstructure and dielectric properties of Ba_0.6Sr_0.4TiO₃（BST） films produced by pulsed-laser deposition technique on both Si（100） and Pt（111）/Ti/SiO₂/Si（100） substrates was studied.It was found that the microstructure of the films changed from a random orientation to（l11） preferred orientation and the grain size was smaller,after inserting the buffer layers.The dielectric properties of BST films deposited on Pt（111） substrates was found to be dependent on the thickness of the buffer layer.Compared with pure BST films,the dielectric properties of buffered BST films was significantly improved,that the dielectric constant and tunability of BST films were increased while its dielectric loss and dispersion were decreased.At 10 kHz,the dielectric constant,tunability,and the dielectric loss of the BST thin films having about 5 nm TiO₂ buffer layer were 513,0.053,and 36.7%,respectively.