bindti3o12薄膜溶胶凝胶法制备及晶粒取向性研究word格式论文.docxVIP

AbstractThe property of ferroelectric thin films has been identified as the essential factor to deter mine the performance of the ferroelectric nonvolatile random access memory (FeRAM). As the furthered investigation of FeRAM, varieties of ferroelectric material has attracted much attention, among which Bi4Ti3O12 ferroelectric thin film is considered as the most promising candidate due to its fatigue-free and lead free nature. A series of investigations about the grain morphology and orientation have been set on the Nd doped Bi4Ti3O12 for its enhanced property in the following work.The ferroelectric Bi3.15Nd0.85Ti3O12(BNT) thin films were fabricated on thePt/Ti/SiO2/Si(100) substrate by the sol-gel process in this thesis. In the annealing stage of thin films fabricating process, the influence of the annealing temperature and the heat treatment approach on the grain morphology and orientation of the films was investigated detailedly. It is shown that the high annealing temperature benefits not only the nucleation of c-axis-oriented grain but also the growth of a-axis-oriented grain. The mechanism of nucleation and growth of thin films was discussed in terms of the relevant phenomena acquired in the experiment, and the competition between nucleation and growth of grain which deter mine the orientation of grain was reasoned out. According to the experimental results, a conclusion was drawn that the grain growth plays a decisive role at low temperatures, while the effect of nucleation is predo minant at high temperatures. Furthermore, the TiO2 seeding layer was introduced to fabricate BNT films on Pt/Ti/SiO2/Si(100) substrate. Related investigation was explored on the effect of annealing temperature and heat treatment approach on the grain morphology and orientation of the films. As the TiO2 seeding layer benefits nucleation of a-axis-oriented grain, it is preferred to fabricate a-axis preferred BNT films. But the mismatch of TiO2 and BNT films is higher