为了制备出压电性能良好、c轴择优生长的氮化铝钪压电薄膜, 本文利用脉冲直流反应磁控溅射法制备了几组氮化铝钪薄膜, 通过控制变量, 并利用X射线衍射仪、扫描电子显微镜和压电系数测试仪等测试设备, 研究了气体流量、功率、衬底温度、缓冲层结构以及掺钪对薄膜结晶质量及性能的影响, 优化了工艺参数。结果表明, 相比于钛铂缓冲层, 使用氮化铝/钛/铂缓冲层制备薄膜, 可以使摇摆曲线半高宽由2.62°降至2.38°。然后, 对钪掺杂机理进行了简单分析, 本文所制备氮化铝钪薄膜的纵向压电系数d33高达-10.5 pC/N, 是纯氮化铝压电系数的1.9倍, XRD图谱及SEM图像表明, 在该掺杂浓度下, 压电系数的提高主要是通过钪掺杂产生的晶格畸变引起, 而非改变了晶体结构。

Stress controllable silicon nitride (SiNx) films deposited by plasma enhanced chemical vapor deposition (PECVD) are reported. Low stress SiNx films were deposited in both high frequency (HF) mode and dual frequency (HF/LF) mode. By optimizing process parameters, stress free (-0.27 MPa) SiNx films were obtained with the deposition rate of 45.5 nm/min and the refractive index of 2.06. Furthermore, at HF/LF mode, the stress is significantly influenced by LF ratio and LF power, and can be controlled to be 10 MPa with the LF ratio of 17% and LF power of 150 W. However, LF power has a little effect on the deposition rate due to the interaction between HF power and LF power. The deposited SiNx films have good mechanical and optical properties, low deposition temperature and controllable stress, and can be widely used in integrated circuit (IC), micro-electro-mechanical systems (MEMS) and bio-MEMS.

Thick SU8 microstructures with high aspect ratio and good side wall quality were fabricated by ultraviolet (UV) lithography, and the processing parameters were comprehensively studied. It proves that the adhesion of SU8 on silicon (Si) substrates is influenced by Si-OH on the surface, and can be improved by the HF treatment. Cracks and delamination are caused by large internal stress during fabrication process, and are significantly influenced by soft bake and post-exposure bake processes. The internal stress is reduced by a low post-exposure bake exposure temperature of 85 °C for 40 min. A three-step soft bake enhances the reflowing of SU8 photoresist, and results in uniform surface and less air bubbles. The vertical side wall is obtained with the optimized exposure dose of 800 mJ/cm2 for the thickness of 160 μm. Using the optimized fabrication process combined with a proper structure design, dense SU8 micro pillars are achieved with the aspect ratio of 10 and the taper angle of 89.86°. Finally, some possible applications of SU8 in micro-electromechanical system (MEMS) device are developed and demonstrated.

研究了基于氮化铝(AlN)薄膜的压电式风致振动微机电系统(MEMS)能量采集单元的制备工艺。采用脉冲直流磁控溅射的方法制备了具有(002)择优取向的AlN压电薄膜,并通过X射线衍射仪(XRD)及扫描电镜(SEM)表征了AlN薄膜的性能。测试结果表明：种子层材料、气体流量比和衬底温度等对AlN薄膜晶体取向及薄膜性能有重要影响。制备的具有(002)择优取向的AlN薄膜的衍射强度达到105count, 半高宽为2.7°。对硅基AlN风致振动MEMS能量采集单元加工工艺流程进行优化，制备出了风致振动能量采集系统原理样机。风洞实验表明，在15.9 m/s的风载荷作用下，MEMS能量采集单元的最大输出功率为1.6 μW。该工艺亦可用于其他硅基AlN薄膜MEMS器件的制备。

力平衡式真空微电子加速度传感器的惯性敏感元件不仅受弹性力的作用,同时还受静电力的作用,其总刚度为机械刚度和由静电力引入的电学刚度之和.本文利用平行板电容器模型计算发射电极间的静电力,并引入一个修正系数描述发射锥尖阵列的影响,对传感器性能进行了理论分析.分析表明,提高偏置电压可以改善传感器的线性度和灵敏度,通过调节偏置电压来调整系统的刚度和阻尼比可使其具有更好的动态特性.由于静电吸合效应的影响,质量块的位移必须小于偏置电极间初始间距的1/3 ,系统才能稳定.为了获得较好的动态特性,需要确定一个由偏置电压决定的优化工作点.实验结果表明,当设置发射电压和反馈偏置电压分别为1.953 V和5.478V时,该真空加速度传感器的灵敏度达到557mV/g,非线性度为0.95%,传感器系统具有良好的性能.

非亚采样Contourlet变换是在非亚采样塔型滤波器及非亚采样方向滤波器组的基础上建立起来的,它是一种移不变多方向多尺度图像表示方法。介绍了该变换的结构特点与系数分布特性,并研究了基于非亚采样Contourlet变换的图像融合算法。该算法利用非亚采样Contourlet的平移不变性以及NSCT系数特点,有效准确地提取图像边缘与细节区域,并分别在高、低频域针对不同区域采用不同的融合方法,有效挖掘了待融合图像中的有效信息。这种具有多分辨率分析和多方向滤波特点的处理方法,提高了融合后遥感图像中的信息量和清晰度,对不同分辨率不同方向上的信息进行挖掘及融合,解决了传统小波融合算法中方向数目受限的不足。通过仿真实验与传统融合方法进行比较,验证了该方法的有效性和优越性。