【作者】 冯斌；

【导师】 王德苗； 金浩；

【作者基本信息】 浙江大学 ， 物理电子学， 2013， 博士

【摘要】 薄膜体声波谐振器(FBAR)具有谐振频率和质量灵敏度高,尺寸小及与CMOS工艺兼容等特点,这些特点使FBAR技术成为制备生物化学传感器的理想技术。但是常规FBAR技术在应用于液态环境时尚存在一些如寄生波多及Q值低等缺陷。为了解决以上缺陷,我们提出了全新的嵌入式电极侧向场激励FBAR,该谐振器工作于纯剪切波模式,所以在液态环境下可以保持较高的Q值。本论文的主要研究内容如下：①对嵌入式电极侧向场激励FBAR进行数学建模；②利用ANSYS设计仿真嵌入式电极侧向场激励FBAR有限元模型；③系统地研究衬底温度对反应溅射沉积AlN薄膜的结构性能和沉积速率的影响,同时研究了室温下紫外线辅助射频反应磁控溅射沉积AlN薄膜的工艺技术；④利用MEMS技术制备了嵌入式电极侧向场激励FBAR。本论文的主要研究成果如下：1.成功地推导并得到了嵌入式电极侧向场激励FBAR的数学模型,证明了其工作于纯剪切波模式,并重新定义了相应的剪切波声速和机电耦合系数的计算公式。2.首次对嵌入式电极侧向场激励FBAR模型进行了ANSYS有限元仿真分析。在此基础上,创新性地分析了嵌入式电极的设计原理并提出了相应的设计遵循公式,申请并获得了“国家自然科学基金青年基金”支持。3.系统地研究了衬底温度对直流和射频反应磁控溅射制备的AlN薄膜的沉积速率和结构性能的影响。适当的衬底温度下直流和射频反应磁控溅射都可制备得到c轴择优取向较好的AlN压电薄膜,但在同等条件下直流反应磁控溅射获得的薄膜性能更好。适当地控制反应溅射参数,在常温下可以利用直流反应磁控溅射制备得到c轴择优取向较好的AlN压电薄膜。相关的成果发表于SCI收录的杂志《Journal of ELECTRONIC MATERIALS》上。4.创新性地研究了室温下紫外线辅助射频反应磁控溅射制备取向可控的AlN压电薄膜。在室温下紫外线辅助沉积薄膜时,只要功率足够高就可以制备得到高c轴择优取向的AlN薄膜；而在高功率下,将氮气和氩气流量比增加到80/40sccm时,可以制备得到(100)择优取向的AlN薄膜。相关的成果发表于SCI收录的杂志《Materials Letters》上。5.与清华大学合作将FBAR器件在低温(低于350℃)工艺下直接集成到了CMOSIC上。相关成果发表于"RF MEMS, Resonators, and Oscillators"的国际会议上。6.首次成功制备了布拉格型嵌入式电极侧向场激励FBAR,其谐振频率为1.61GHz。本论文所涉及的研究对FBAR传感器在生物化学传感领域的应用具有积极的推动作用。更多还原

【Abstract】 Film bulk acoustic resonators (FBARs) exhibit high resonant frequency, high mass sensitivity, small size and CMOS-compatibility, thus making this technology a promising candidate for chemical and biology sensors. But there are still some shortcomings, such as the existence of spurious modes and the reduction of Q value in liquid environment. We proposed a novel lateral field excited FBAR with embedded electrodes, which has the advantages of pure shear mode resonance and high Q value in liquid environment.The main research contents are:①conducted a mathematical analysis of the lateral field excited FBAR with embedded electrodes;②developed various finite-element models (FEMs) of the lateral field excited FBAR with embedded electrodes and implemented the analysis using ANSYS;③systematically studied the influence of substrate temperature on structural properties and deposition rate of AlN thin film deposited by reactive magnetron sputtering and investigate ultra-violet light assisted reactive RF magnetron sputtering technology for deposition of AlN thin films at room temperature;④prepared a lateral field excited FBAR with embedded electrodes with MEMS technology.The main results of this research are listed as follows:1. We had got a mathematical mode of the lateral field excited FBAR with embedded electrodes, proved that this FBAR worked in pure shear wave mode, refined the formula of the shear mode wave velocity and electromechanical coupling coefficient.2. We investigated the lateral field excited FBAR with embedded electrodes with finite-element models study using ANSYS for the first time. Based on this, we creatively analysis the principle and proposed a formula for of the design of embedded electrodes. This work had applied for and got supported by the "National Natural Science Foundation of China Youth Foud".3. Systematically invstigated the influence of substrate temperature on structural properties and deposition rate of AlN thin film deposition by direct current (DC) or radio frequency (RF) reactive magnetron sputtering. AIN thin film with good C-axis preferred orientation would be prepared under appropriate substrate temperature by both DC and RF reactive magnetron sputtering, but DC performed better at the same condition. AIN thin film with good C-axis preferred orientation can be prepared at room temperature by DC reactive magnetron sputtering with optimal condition. The research had been published in "Journal of ELECTRONIC MATERIALS", which was cited by SCI.4. Proposed and developed a UV-light assisted RF reactive magnetron sputtering method to deposite AIN thin film with controlled crystal orientation at room temperature.(002) oriented columnar AIN crystal can be deposited at high power; while (100) oriented crystal structure can be obtained when the N2/Ar flow ratio is increased to80/40sccm with UV-light assistance at room temperature by RF reactive magnetron sputtering. The research had been published in "Materials Letters", which was cited by SCI.5. We had fabricate a FBAR on a CMOS IC at quite low temperature below350℃cooperate with tsinghua university. The research had been presented on "RF MEMS, Resonators, and Oscillators".6. For the first time, we had successfully prepared a lateral field excited FBAR with electrodes and Bragg reflector, the resonant frequency is1.61GHz.The research of this doctoral dissertation will promote the development of FBAR technology in chemical and biology sensing applications.更多还原