Highly tunable and temperature insensitive multilayer barium strontium titanate films

Multilayered Ba1-xSrxTiO3 (BST) films were deposited on Pt coated Si substrates via metalorganic solution deposition. The multilayer heterostructures consisted of three distinct layers of similar to 220 nm nominal thickness with compositions corresponding to BST 63/37, BST 78/22, and BST 88/12. At room temperature, the heterostructure has a small-signal dielectric permittivity of 360 with a dissipation factor of 0.012 and a dielectric tunability of 65% at 444 kV/cm. These properties exhibited minimal dispersion as a function of temperature ranging from 90 to -10 degrees C. These results are explained via a thermodynamic model that incorporates electrical, mechanical, and electromechanical interactions between BST layers. (c) 2007 American Institute of Physics.