Journal of the American Ceramic Society, Vol.88, No.9, 2652-2654, 2005
Preparation of sputtered (Ba-x,Sr1-x)TiO3 thin films directly on copper
(Ba-0.6,Sr-0.4)TiO3 (BST) films were deposited on copper foils by radio frequency magnetron sputtering. By the use of controlled pO(2) high-temperature anneals, the films were completely crystallized in the absence of substrate oxidation. X-ray diffraction and transmission electron microscopy (TEM) revealed an abrupt Cu/BST interface. The deposited BST films exhibit a zero bias permittivity and loss tangent values of 600 and 0.018, respectively. An electrical tunability ratio of 3.5:1 is observed on these metal-insulator-metal devices. Devices show leakage currents of 10(-8) A/cm(2) at +/- 10 V/mu m, and loss tangents as low as 0.003 in fields approaching 40 V/mu m.