BST薄膜射频溅射沉积及性能的研究.pdf

华中科技大学硕士学位论文 BST薄膜的射频溅射沉积及性能研究姓名:王亚鹏申请学位级别:硕士专业:微电子学与固体电子学指导教师:胡作启 20090525 华中科技大学硕士学位论文 I 摘要 Ba x Sr 1-x TiO 3 (BST) 是一种性能优良的铁电材料, 在微波领域有非常广泛的应用。本文采用射频磁控溅射法在 Si 衬底上成功制备了 BST 薄膜,并研究了不同溅射工艺参数对薄膜结构及介电性能的影响,总结了最佳溅射工艺。射频磁控溅射溅射的 BST 薄膜,在( 111 )晶面择优取向生长。退火处理可以使 BST 薄膜结晶度更高,晶粒生长更加完整,能很好地释放薄膜生长过程中所造成的内应力。衬底温度越高,薄膜结晶越好。高氧氩比的溅射气氛有利于 Sr 、 Mg 、 O 原子的沉积,而在低氧氩比的溅射气氛中, Ba 、 Ti 原子的沉积速率较快。高氧氩比气氛溅射的薄膜表面有针孔出现,质量不如低氧氩比气氛中溅射的薄膜。薄膜内部晶粒的发育状况不如表面晶粒,其粒径很小,而且晶粒与晶粒之间还存在一定的非晶成分。衬底温度对薄膜的沉积速率影响较小,在功率 250W 、溅射气压 、氧氩比为 1/3 的溅射工艺下,估算薄膜的沉积速率大约为 16nm/min 。 BST 薄膜在微波频率下( 10GHz 左右)的介电常数大约在 500 ~ 800 之间,介电损耗在 ~ 之间。综合介电常数和介电损耗两方面,其中衬底温度为 600 ℃、氧氩比为 1/3 工艺条件下溅射的薄膜介电性能最佳。关键词: 钛酸锶钡;射频磁控溅射;薄膜;微波介电性能华中科技大学硕士学位论文 II Abstract Ba x Sr 1-xTiO 3(BST), with excellent proe rties, has been widely us ed in microwave field. We essfully prepared BST thin films on Si substrate by RF ron sputtering and investigated the structure and dielectric prope rties of BST films with different process parameters, and summarized the be st sputtering process condition. BST thin films by RF ron sputteri ng indicated a high pr eference for (111) orientation. Annealing enabled BST films a higher degree of crystallinity, a more completeness of grains growth and a good release of the internal stress. The higher substrate temperature was the be tter crystalline of BST films oxygen-argon-ratio sputtering atmosphere was helpful for the deposition of Sr, Mg, O. The accumulate rate of Ba, Ti was fast er in low oxygen-argon-ratio sputtering atmosphere. The film in high oxygen-argon-ratio sputtering atmosphere had pinholes on the surface, and the quality of film was worse than that of in low oxygen-argon-ratio sputtering atmosphere. Internal BST crystallin e grains grew not so well as on the surface, because they were small and grew on diff erent orientations, besides there were ponent among them. The substrate tempratrue has limited effect on the accumulate rate of film, the average accumulate ra