铁电薄膜微图形化及其电性能相关性研究

The development trend of the integrated ferroelectric devices is the high-density, miniaturized, high performance, which asked for higher requirements for the micro-graphics of ferroelectric thin films. Therefore, for the purpose of preparing the high-performance ferroelectric devices, in addition to the excellent preparation of ferroelectric thin films, the preparation of micro-graphics has also become one of the key technologies. The ferroelectric thin film micro-graphics preparation on the development of ferroelectric devices has important theoretical significance and practical value. PZT, BST ferroelectric thin film micro-graphical, however, there are still much difficulty to overcome. Even, there is almost no report about BZN thin films of ferroelectric phase micro graphical, not to mention the research of the correlation of micro-graphical and its electrical properties, which can not match the requirements of increasing development of ferroelectric devices integration. Our research in recent years show that the biggest challenge of ferroelectric thin film micro-graphical is to get no damage key technology, that is to obtain the optimized and matched etching techniques and post-stripping process parameters. The research topic on the basis of the lithography intend to use RIE technology with ICP plasma source, the film surface composition and chemical state will be analyzed to explore the mechanism of the etching process with different gases, and research the influence of the process parameters on micro-graphical and electrical performance-related, and solve the problem of low yield of the device.

集成铁电器件的发展趋势是高密度、微型化、高性能，这就对铁电薄膜的微细图形提出了更高的要求。因此制备高性能的铁电器件，除了制备优良的铁电薄膜以外，其微细图形制备也成为关键技术之一，铁电薄膜微图形制备对铁电器件的发展具有重要的理论意义和实用价值。然而PZT、BST等铁电薄膜微图形化还存在许多未克服的难点，铁电相的BZN薄膜的微图形化报道更是甚微，更不用说微图形化与其电性能相关性的研究，这与日益发展的铁电器件集成度不断要求提高很不匹配。本科研小组近年来预研结果表明当今铁电薄膜微图形化最大挑战是获得无损伤的关键技术即最优化的相互匹配刻蚀技术和后期去胶工艺参数；本课题在光刻的基础上，拟采用ICP等离子源的RIE技术，对薄膜表面成分和化学态分析，探讨各工艺气体对薄膜的刻蚀机理；研究工艺参数对其微图形化及性能相关的影响规律；从而解决器件制备过程中产生的成品率低的问题。

由于集成铁电器件的发展趋势是高密度、微型化、高性能，这就对铁电薄膜的微细图形提出了更高的要求。本课题在制备铁电介电BZN、BST薄膜的基础上，研究了薄膜的微图形制备的关键技术，研究了光刻微图形的关键参数，得到了最优化的可重复性的参数；研究了刻蚀的各工艺参数（包括刻蚀气体压强，刻蚀功率、刻蚀气体的比率，以及ICP的功率等参数）对薄膜的刻蚀规律如刻蚀速率的影响，表面成分的影响以及结构及介电常数及介电损耗的影响， 探讨各工艺对薄膜的刻蚀机理；研究表明，刻蚀RIE及ICP功率增大刻蚀速率增大，但是根据薄膜的性能的结果，我们通过交叉法选择更优化的工艺参数，即有利于薄膜结构及性能的保持，又利于后期无损伤的去胶。此外采用了理论的方法计算刻蚀残余物对薄膜性能的影响，结果表明，这种氟化物残余影响了薄膜能带结构及介电性能。这些结果为下一步制备期间提供了有利数据。