快速热处理对(Ba,Sr)TiO_3薄膜晶化行为的影响

Effect of Rapid Thermal Annealing on the Crystallization of (Ba,Sr)TiO_3 Thin Films

采用射频溅射法在Si(111)基片上制备了(Ba,Sr)TiO3(BST)薄膜,并对制备的薄膜进行了快速退火热处理。采用X射线衍射和原子力显微镜分析了退火温度、退火时间和加热速度对BST薄膜晶化行为的影响。研究结果表明,BST薄膜的晶化行为强烈依赖于退火温度、退火时间和加热速度。BST薄膜的结晶度随退火温度的升高而提高。适当的热处理可降低BST薄膜的表面粗糙度,BST薄膜的表面粗糙度随退火温度的升高经历了一个先降低后增大的过程,但退火后BST薄膜的表面粗糙度都小于制备态薄膜的表面粗糙度。BST薄膜的晶粒尺寸随退火温度的升高经历了一个先增大后减小的过程。随退火时间的延长,BST薄膜的特征衍射峰越来越强,薄膜的晶化程度越来越高。随退火时间的延长,BST薄膜的晶粒尺寸和表面粗糙度也经历了一个先增大后减小的过程。BST薄膜的晶粒大小主要由退火温度决定。高的升温速率可获得较小的晶粒。

The rapid thermal annealing（RTA）process is adopted to anneal the （Ba, Sr）TiO3 （BST）thin films prepared on Si（111）substrats by RF magnetic sputtering deposition. The effects of annealing temperatrue, annealing time and heating rate on crystallization behaviors are systematically studied. The microstructures of the BST thin films are explored by XRD and AFM. The results show that crystallization behaviors of the BST thin film are strongly dependent on the annealing temperature, the annealing time and the heating rare. The crystallization degree of the BST thin films is improved with the increase of annealing temperature. The proper annealing can decrease the root mean square （RMS）roughness of the BST thin film. The RMS roughness of the BST thin films decreases at first, and then increases with the annaling temperature increase. But,the RMS roughness of the BST thin films is less than that of the as-deposited film. However, the grain size of the BST thin films increaese at first, and then decreases with the annealing temperatrre increase. With the increase of the annealing time, the XRD peak intensity increase, which implies that the crystallization degree increawses. And the grain size and the RMS roughness increase at first, and then decrease with the annealing time increasing. Compared to annealing time, the grain size of the BST thin films is mainly dependent on the annealing temperature. Higher heating rate results in smaller grain size.