Effect of Sputtering Processes on Dielectric Constants of BST Thin Films

Ba0.5Sr0.5TiO3(BST)thin films about 700 nm in thickness were prepared by rf magnetron sputtering on ITO-coated glass substrate. The influence of sputtering power, gas pressure, ψ[O2/(Ar+O2)] ratio,and substrate temperature on dielectric constant of the BST thin films was investigated. The dielectric constants under various deposition parameters are between 250~310. The base pressure of 10–3 Pa, substrate-target distance of 6.2 cm, sputtering power of 300 watts, gas pressure of 1.8 Pa, ψ[O2/(Ar+O2)] ratio of 30% and substrate temperature of 500℃ are identified to be a better sputtering process. The crystallinity, composition as well as morphology of the BST film deposited under the better condition was also studied.