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设计制作了一种基于氧化锌纳米线的谐振式硅加速度计,该加速度计的敏感单元为由氧化锌纳米线横跨金属微电极组成的谐振器。采用介电电泳的方法组装了氧化锌纳米线,并利用FIB沉积Pt将氧化锌纳米线固定在微结构上以确保结构的可靠性。在加速度的作用下,质量块引起的惯性力通过支撑梁对纳米线施加应力,因此,在谐振条件下,纳米线谐振频率的变化反映了加速度的大小。谐振式加速度计的准数字输出能解决多数MEMS器件输出微弱信号检测难的问题。实验结果表明,加速度计的灵敏度随着纳米线的厚度的减小而急剧增加,选择500nm厚度的纳米线作为理论分析,加速度计的灵敏度可达2.5kHz/g以上。
A resonant silicon accelerometer based on zinc oxide nanowires was designed and fabricated. The sensitive unit of the accelerometer is a resonator composed of zinc oxide nanowires across the metal microelectrode. Zinc oxide nanowires were assembled by dielectrophoresis method and Pt was used to immobilize ZnO nanowires on the microstructures with FIB to ensure the structural reliability. Under the action of acceleration, the mass-induced inertial force exerts stress on the nanowires through the support beam. Therefore, under resonant conditions, the change of the resonant frequency of the nanowire reflects the magnitude of the acceleration. The quasi-digital output of a resonant accelerometer solves the problem of the weak signal detection of most MEMS devices. The experimental results show that the sensitivity of the accelerometer increases sharply with the decrease of the thickness of the nanowire. The sensitivity of the accelerometer can reach above 2.5kHz / g with the nanowire of 500nm as the theoretical analysis.