射频磁控溅射参数对 Ba0.7Sr0.3TiO3薄膜结构和性能的影响

摘要

采用射频磁控溅射法在 Pt/TiO2/SiO2/Si(100) 衬底上制备了Ba0.7Sr0.3TiO3薄膜,研究了工作气压、衬底温度等溅射参数对Ba0.7Sr0.3TiO3薄膜结构和电学性质的影响.使用 XRD 分析了工作气压为 2Pa、衬底温度分别为 200 ℃、400 ℃、600℃(组a),以及衬底温度为600℃、工作气压分别为 1.5Pa、2.0Pa、2.5Pa、3.0Pa 和 5.0Pa (组b)两组薄膜的微结构,结果表明工作气压在 2.5Pa 以下、衬底温度为 600℃时沉积的薄膜具有较好的钙钛矿结构.在 1.5Pa 条件下溅射的薄膜具有明显的(111)择优取向.在2.5Pa时,Pt/Ba0.7Sr0.3TiO3/Pt电容有最优铁电性能,在外加4 V电压(电场为 80 kV/cm)下,剩余极化 (Pr) 和矫顽场(Ec)分别为 2.32 μC/cm2、21.1 kV/cm.%The Ba0.7Sr0.3TiO3 thin films were prepared on a stabilized Pt/TiO2/SiO2/Si(100) substrate by RF-sputtering. The effect of working gas pressure and substrate temperature on structure and electrical properties of the Ba0.7Sr0.3TiO3 thin films were studied. The structure of the thin films deposited at the substrate temperature of 200 ℃ ,400 ℃ and 600 ℃ with a fixed working pressure of 2.0Pa (group a), and at the working pressure of 1.5Pa, 2.0Pa, 2.5Pa, 3.0Pa and 5.0Pa with a fixed substrate temperature of 600 ℃ (group b) were characterized by XRD analysis. The results showed that the thin films could develop a perovskite structure when the pressure was lower than 2. Spa and at a substrate temperature of 600 ℃. And at the pressure of 1. 5Pa, the thin film grew with a (111)-preferred orientation. The best electrical values had been measured for the capacitor sample Pt/Ba0.7 Sr0.3TiO3/Pt fabricated at the working pressure of 2. 5 Pa. And at an applied electric voltage of 4 V (the electric field was about 80 kV/cm), the remnant polarization (Pr) and coercive field (Ec) from the P-V loop measure-ments were about 2. 32 μC/cm2 and 21.1 kV/cm.