三明治双桥微结构催化燃烧式气体传感器的设计与实现

Design and realization of catalytic combustion-type gas sensor with sandwich dual bridge microstructure

针对传统的催化燃烧式气体传感器因手工制作,造成配对难、一致性差、功耗高、不能互换等问题,基于硅MEMS技术设计并制造了一种集成双桥催化燃烧式酒精气体传感器。通过ANSYS有限元分析方法对传感器的温度场进行分析,采用硅氧化-PECVD-氧化工艺制作三明治结构的SiO2-Si3N2-SiO2微双桥结构载体,湿法腐蚀掉硅形成梁膜结构,减少热功耗。采用薄膜工艺制作铂膜敏感电阻,涂敷纳米Al2O3-ZrO-ThO形成载体,在敏感单元上浸渍pt-pd催化剂溶液,形成催化敏感桥臂,未涂覆催化剂载体构成参比单元,实现在微双桥上的芯片集成,制成传感器。电镜观察了Pt薄膜电阻的线条,能谱分析了载体敏感材料和补偿材料成分。测试结果表明:传感器可实现体积分数0~4 500×10-6酒精检测,具有良好的线性输出特性,温度为-20^+40℃和湿度范围为30%RH^85%RH的传感器的最大零点输出小于±2.0%FS,功耗≤0.2 W,响应恢复时间均在30 s以内。

Aiming at the problems of traditional catalytic combustion-type gas sensor, such as matching difficulty, poor consistency, high power consumption and poor interchangeability due to manual manufacturing, in this paper a kind of integrated dual bridge catalytic combustion-type alcohol gas sensor is designed and manufactured based on silicon MEMS technology. With ANSYS finite element analysis method the temperature field of the sensor was analyzed ,the sil- icon oxidation-PECVD-oxidation technique was adopted to produce the SiO2-Si3 N2-SiO2 microstructure dual bridge car- tier with sandwich structure,wet etching method was used to etch the silicon and form a beam structure for reducing the heat consumption. The thin film technology was used to manufacture the platinum film sensitive resistor, and the nano Al2O3-ZrO-ThO. was coated to form the sensor carrier, the Pt-Pd catalyst solution was dipped on the sensitive unit to form the catalytic sensitive bridge arm, the catalyst carrier without coating was used as the reference unit, the chip inte- gration on the micro double bridge was realized, and the sensor was manufactured. The Pt film resistor lines were ob- served with the electron microscope, the compositions of the carrier sensitive material and compensation material were analyzed with energy spectrum method. The test results show that the sensor can realize the detection of alcohol with the volume fraction of 0-4 500 × 10-6, has good linear output characteristic ;within the temperature range of 20--40 ℃ and humidity range of 30% RH -85% RH,the maximum zero output of the sensor is less than ±2.0% FS,the power con- sumption is not larger than 0.2 W, both of the response and recovery time are less than 30 s.