Microstructure and electrical properties of sputtered Ba(Sr)TiO₃ films: Dopant and crystal structure effects

Ferroelectric oxide thin films with a perovskite structure, such as BaTiO₃ (BT), (Ba,Sr)TiO₃ (BST), have attracted considerable attention, because of their potential applications in memories, thin film capacitors, and electro-optics. Obtaining thin films with properties approaching bulk forms as well as understanding the formation mechanism of films would contribute general insight into thin film physics and accelerate its practical applications in many devices. This presentation will first show the crystallization behavior of BT film using XRD and thermal analyses techniques. MgO has been reported to add to BST to form a ceramic composite in order to dilute the sensitivity of dielectric constant to environmental stress and further suppress the dielectric loss at high frequencies. Further, the dopant (such as Ho₂O₃) has been shown to have beneficial effects on the property improvement of bulk BT. In this presentation, effects of the additives such as Ho₂O₃ and MgO on the crystal structures as well as electrical properties of BT and BST films are discussed.