文档介绍：华中科技大学
硕士学位论文
LSCO/PZT/LSCO集成铁电薄膜生长与性能研究
姓名:赵远
申请学位级别:硕士
专业:微电子学与固体电子学
指导教师:于军
2011-01-17
华中科技大学硕士学位论文
摘要
与传统 E2PROM,FLASH 等非挥发性存储器相比,新型非挥发铁电存储器 FRAM
具有低操作电压、快速读写操作、低功耗、信息保持时间长等优异的特性,因而非常
适合于嵌入式开发应用。其中集成铁电薄膜是实现铁电存储器的关键。本论文主要研
究了集成铁电薄膜 LSCO/PZT/LSCO 下缓冲层 LSCO 的靶材制备,磁控溅射工艺参数
优化以及薄膜自发形核热力学分析。
按照热力学理论,重点研究分析了薄膜生长过程中的自发形核过程。通过分析临
界核心半径 r*,自由能变化ΔG * 两参量,来探讨衬底温度和沉积速率对整个形核过
程及组织结构的影响。结果表明,适当提高衬底温度 T,并降低沉积速率 U 可沉积得
到晶粒粗大甚至具有单晶结构的薄膜。
采用溶胶凝胶自燃烧法制备出的靶材优化阈值为:烧结温度 1200
℃,镧过量系数λ= 。在此条件下制备的靶材表面平整,晶粒均匀,结合致密,孔
洞缺陷极少,电阻率最低可达到 mΩ·cm。
改变制备 LSCO 薄膜的衬底温度和溅射功率两工艺参数,通过分析研究射频磁控
溅射制备得到的 LSCO/PZT/LSCO 集成铁电薄膜的各种性能,最终确定出制备 LSCO
下缓冲层的优化阈值:衬底温度 600 ℃,溅射功率 100 W。在此条件下集成铁电薄膜
物相单一,且沿着(110)晶向择优取向;核心层 PZT 薄膜结晶良好,晶粒均匀,晶界
清晰,表面平整,且没有孔洞,致密性很好;薄膜的剩余极化强度达到 80 μC/cm2,
矫顽电压为 V;经过 1010 次极化反转之后,剩余极化强度仍然维持在 96%以上。
关键词:LSCO/PZT/LSCO 铁电薄膜溶胶凝胶自燃烧射频磁控溅射
铁电性能疲劳特性
I
华中科技大学硕士学位论文
Abstract
Compared with the traditional E2PROM, FLASH and any other non-volatile memories,
the new kinds of non-volatile ferroelectric memories (FRAM), which are very suitable for
the requirements of embedded applications, have many more better advantages, such as
lower operating voltage, faster read-write operation, lower power consumption, more long
time retention and so on. As the core of integrated ferroelectric device, ferroelectric thin
film is the key to fulfill the FRAM. Therefore, in order to improve the fatigue properties of
the PZT ferroelectric thin films used currently in the ferroelectric memories, on the one
hand, this paper mainly focused on the preparation of the LSCO targets, which were used to
prepare the LSCO thin film layer for the LSCO/PZT/LSCO sandwiched ferroelectric thin
films by the RF-ron sputtering technology. On the other hand, two main parameters
during in the sputtering technology had been optimized by the experimental analysis and
research, substrate temperature and sputtering power, respectively. Thirdly, spontaneous
nuclea