Fu Xiaorui, Xu Lizhong
Mechanical Engineering Institute, Yanshan University, Qinhuangdao 066004, China.
Sensors (Basel). 2018 Jan 26;18(2):362. doi: 10.3390/s18020362.
In micro-resonant gas sensors, the capacitive detection is widely used because of its simple structure. However, its shortcoming is a weak signal output caused by a small capacitance change. Here, we reduced the initial clearance between the pole plates to the nanometer level, and increased the capacitance between the pole plates and its change during resonator vibration. We propose a fabricating process of the micro-resonant gas sensor by which the initial clearance between the pole plates is reduced to the nanometer level and a micro-resonant gas sensor with 200 nm initial clearance is fabricated. With this sensor, the resonant frequency shifts were measured when they were exposed to several different vapors, and high detection accuracies were obtained. The detection accuracy with respect to ethanol vapor was 0.4 ppm per Hz shift, and the detection accuracy with respect to hydrogen and ammonias vapors was 3 ppm and 0.5 ppm per Hz shift, respectively.
在微谐振气体传感器中，电容式检测因其结构简单而被广泛应用。然而，其缺点是电容变化小导致信号输出微弱。在此，我们将极板间的初始间隙减小到纳米级别，并增加了极板间的电容及其在谐振器振动时的变化。我们提出了一种微谐振气体传感器的制造工艺，通过该工艺可将极板间的初始间隙减小到纳米级别，并制造出初始间隙为200纳米的微谐振气体传感器。使用该传感器，在其暴露于几种不同蒸汽时测量了谐振频率的偏移，并获得了高检测精度。相对于乙醇蒸汽的检测精度为每赫兹偏移0.4 ppm，相对于氢气和氨气蒸汽的检测精度分别为每赫兹偏移3 ppm和0.5 ppm。
