Joint study on high performance resonant sensors

在本研究中，研究了新型微加工工艺的发展和谐振传感器的制造。总结如下。为了制造高灵敏度微谐振器，建立了用于SPM应用的具有极窄间隙对极的薄悬臂梁的制造工艺。硅悬臂梁的厚度和悬臂梁与玻璃基板之间的间隙小于1微米。为了避免液体表面张力造成的粘连，提出了一种新的干燥方法。为实现高Q因子，研究了微谐振腔的真空封装。气体分子的阻尼降低了微谐振器的Q因子。提出了采用玻璃硅阳极键合和不可蒸发吸气剂的真空封装方法，并将其应用于传感器的制造中。研制了一种采用静电激励和电容检测的硅谐振角速率传感器。该装置实现了静电伺服驱动检测电路、自振荡电路和检测谐振稳频电路。研制了一种采用电磁激励和电容检测的硅谐振角速率传感器。封装式传感器工作效率高，Q因子高。为制作该传感器，研制了一种新型的反应离子刻蚀系统。提出了一种制造薄型窄硅梁谐振器的新工艺。采用XeF_2干刻蚀和SiO_2热刻蚀的方法，实现了60平方截面的硅光束。研究了大振幅振动的压电激励方法。压电薄膜的沉积方式对其压电性能有很大影响。沉积方法有待进一步研究。

In this study, the developement of novel micromachining processes and the fabrication of resonant sensors were done. Summary is as follows.1. For making high sensitive micro resonator, the process for fabricating thin cantilever having an opposed electrode with a very narrow gap for SPM application was established. Thickness of the silicon cantilever and the gap between the cantilever and a glass substrate were less than 1mum. The novel drying method was developed for avoiding stiction by the surface tension force of liquid.2. Vacuum packaging of micro resonator was studied for realizing high Q factor. Damping by gas molecules degrade the Q factor of the micro resonator. Vacuum packaging method using glass-silicon anodic bonding and non-evaporable getter was developed and applied to the sensor fabrication.3. A silicon resonant angular rate sensor using electrostatic excitation and capacitive detection was developed. For this device, driving and detection circuit, self oscillation circuit, and detective resonant frequency stabilizing circuit for electrostatic servo were realized.4. A silicon resonant angular rate sensor using electromagnetic excitation and capacitive detection was developed. Packaged sensor was work and had high Q factor. For the fabrication this sensor, a new type reactive ion etching system was developed.5. Novel process for making thin and narrow silicon beam of resonators was developed. By this process using XeF_2 dry etching and thermal SiO_2, a silicon beam having 60mum square cross-section beam was realized.6. Piezoelectric excitation method for large amplitude vibration was studied. Deposition method of piezoelectric thin film largely affected the piezoelectric properties. Deposition method should be investigated in future.