【作者】 尹伊；

【导师】 叶辉； 吴兰；

【作者基本信息】 浙江大学 ， 光学工程， 2011， 博士

【摘要】 本文探讨了钛酸锶钡(BST)、铌酸锶钡(SBN)和锆钛酸铅(PZT)三种重要铁电材料的薄膜生长和器件制备工作。对于钛酸锶钡(BST)材料,我们研究了成份为Ba0.7Sr0.3Ti03(BST30)的薄膜溶胶-凝胶(Sol-Gel)生长工艺及其原理。通过对其晶相,截面微结构和表面形貌的测试,重点研究了MgO缓冲层取向和厚度对BST30薄膜结构的影响,同时结合薄膜光学性能(拟合薄膜折射率和厚度)和电学性能测试(Ⅰ-Ⅴ曲线测量),分析了MgO缓冲层对BST30薄膜性能的影响；对于铌酸锶钡(SBN)材料,我们研究了成份为Sr0.75Ba0.25Ti03(SBN75)的薄膜在TiN和MgO缓冲层上的磁控溅射制备工艺。通过引入低温自缓冲层,在MgO(001)缓冲层上得到了高择优c轴取向生长的SBN75薄膜,并结合X射线衍射,扫描电子显微镜,原子力显微镜等方法研究了其生长机理。实验中还通过组分分析,研究了SBN75溅射靶材和膜层之间的成分差异以及TiN(001)缓冲层在制备SBN75薄膜过程中产生的氧化现象及其影响。SBN/MgO/Si膜系构成波导结构的应用条件则通过计算各层薄膜折射率和MgO层肌肤深度来加以确定；对于锆钛酸铅(PZT)材料,我们研究了成份为Pb(Zr52Ti48)O3(PZT52)的薄膜Sol-Gel生长工艺及其原理,并在此基础上,利用其良好的d31和d33压电特性,设计并制备了具有平行平板(d31模式)和环形叉值(IDT模式)两种电极结构的单压电片型鼓膜驱动器阵列。通过动态和静态性能分析表明,两种模式的压电鼓膜在低电压下(0～15V)具有良好的驱动能力(最大形变量>2gm)。文中还利用有限元方法(FEM)拟合了压电鼓膜的表面面形并分析了形变成因,同时在夹持状态下,分析了热效应对无鼓膜结构阵列单元形变量的影响。通过上述研究工作,我们初步掌握了制备高质量铁电薄膜及其MEMS器件的工艺方法,为后期开展铁电-硅微电子集成系统(FSMIS)的研究奠定了良好的基础。更多还原

【Abstract】 In this paper, growth of the important ferroelectric films, including strontium barium titanate (BST), strontium barium niobate (SBN) and lead zirconate titanate (PZT), and fabrication of the relevant devices were reviewed. For BST material, the Sol-Gel growth mechanism of Ba0.7Sr0.3TiO3 (BST30) thin film was studied. The crystal phase, cross-sectional micro structure and surface morphology results indicated that the orientation and thickness of MgO buffer layer can mainly affect the microstructure of BST30 film. By measuring the optical (the refractive index and thickness fitting process) and electrical properties (measurement ofⅠ-Ⅴcurve), the action of MgO buffer layer on the character of BST30 film was also estimated. For SBN material, the Sr0.75Ba0.25Nb2O6 (SBN75) thin films were deposited on silicon substrate with MgO (100) and TiN (100) buffer layer by radio-frequency magnetron sputtering technique. By introducing a 900℃annealed SBN self-buffer layer before SBN75 deposition, the highly c-axis orientation of SBN75 thin film can be obtained on MgO buffer layer. The mechanism was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The composition analysis showed that the SBN75 films had target-film composition transfer and the TiN buffer layer was partially oxidized during SBN growth. Moreover, the conditions for SBN/MgO/Si treated as waveguide structure were also determined by calculating the refractive index of each layer and penetration depth of MgO buffer layer. For PZT material, two types of unimorph actuator arrays were fabricated based on the excellent d31 and d33 piezoelectric properties of Sol-Gel derived Pb(Zr0.52Ti0.48)O3 (PZT52) thin film. The actuator arrays utilized diaphragm structures, in which the PZT52 layers were driven by interdigitated electrodes (IDT-mode) and parallel plate electrodes (d31-mode), respectively. Test results showed that both piezoelectric diaphragms had good dynamic and static performance, which can generate considerable deflections (>2μm) at low voltage (0～15V). Moreover, the intrinsic strain conditions shaping the deflection profiles for the diaphragm actuators were evaluated with finite element method (FEM). The clamped parallel plate configuration without a diaphragm was also characterized to estimate the thermal effects in actuators under DC applied voltage.Through the above studies, we have mastered the process of fabricating high-quality ferroelectric thin films and MEMS devices, which lays a good foundation of further research in the filed of Ferroelectric-Silicon Microelectronics Integrated Systems (FSMIS).更多还原