硅基BaTi2O5铁电薄膜的脉冲激光沉积、结构调控及其介电性能

项目名称： 硅基BaTi2O5铁电薄膜的脉冲激光沉积、结构调控及其介电性能

项目编号： No.50802071

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 王传彬

作者单位： 武汉理工大学

项目金额： 22万元

中文摘要： 项目以硅基BaTi2O5薄膜的脉冲激光沉积、结构调控及其性能研究为目标，首先建立了高质量BaTi2O5靶材的制备技术，利用电弧熔炼结合放电等离子烧结技术获得了物相单一、大尺寸（直径20-50mm）、高致密度（97.7%）的BaTi2O5陶瓷；在此基础上，以BaTi2O5陶瓷为靶材，利用脉冲激光沉积技术在Si衬底上制备BaTi2O5薄膜，重点研究了沉积工艺（激光能量密度、氧分压、沉积温度）对薄膜物相、结晶取向、表面形貌和微观结构的影响；建立了BaTi2O5薄膜的脉冲激光沉积技术，解决了其可控生长的技术难题，通过优化沉积工艺、采用MgO缓冲层和采取适宜的结构调控方法，获得了物相单一、b轴择优取向、表面平整致密，而且具有优良介电（介电常数1985@100 kHz，居里温度748K）、铁电（剩余极化强度14.2uC/cm2）和光学性能（透过率>70%）的硅基BaTi2O5薄膜，为新一代铁电存储器的应用提供了一种无铅、环境友好的薄膜新材料。项目在国内外学术期刊上发表学术论文10篇（其中SCI收录3篇，EI收录4篇），申请国家发明专利3项，培养博士、硕士研究生4人。

中文关键词： BaTi2O5薄膜；硅基；脉冲激光沉积；MgO缓冲层

英文摘要： In the present project, the preparation, structural controlling and property of BaTi2O5 thin films, which were deposited on Si substrates by pulsed laser deposition (PLD), were conducted. At first, single-phased and large-scaled BaTi2O5 ceramics with a high densification of 97.7% were obtained by arc-melting followed by spark plasmas sintering. Then by using BaTi2O5 ceramics as the targets for film deposition, BaTi2O5 thin films were prepared by PLD and the effects of deposition parameters (laser energy density, oxygen partial pressure, substrate temperature) on the crystal phase, orientation, surface morphology and microstructure of the films were mainly investigated. The optical, dielectric and ferroelectric properties of BaTi2O5 thin films were also tested, and the relationship between the composition, structure and property was established. Finally, the optimized b-axis oriented BaTi2O5 thin films with large dielectric constant, high Curie temperature, high remanent polarization and transmittance were successfully prepared by employing the optimum deposition conditions and using MgO(100) films as the buffer layers. Under the financial support of this project, 10 papers were published, 3 patents were applied and 4 postgraduate and Ph. D students were cultivated. The achievements of the project could supply a new lead-free and environmentally-friendly ferroelectric material for the application of Ferroelectric Random Access Memory (FRAM) or Dynamic Random Access Memory (DRAM).

英文关键词： BaTi2O5 thin film；Si substrate；pulsed laser deposition；MgO buffer layer