【作者】 冯侨华；

【导师】 孙立宁；

【作者基本信息】 哈尔滨理工大学 ， 精密仪器及机械， 2014， 博士

【摘要】 人们逐渐认识到室内空气污染有时比室外更会危害人体健康，如何采取安全预警措施避免事故发生已成为当今国家和社会十分关注的安全问题。目前，室内污染气体的检测方法有很多，其中，传感器法具有使用简单，除维修校正外，无需操作可直接读数，无需专业人员操作，适用于在线检测等优点。但是，随着物联网技术的发展，传统的传感器因缺乏集成和嵌入功能，已无法满足系统匹配的需求，而MEMS传感器的高度集成化和兼容性为解决这一问题带来希望。MEMS传感器以硅基芯片为研究热点，目前的硅基MEMS传感器以压力、加速度、位移等物理量传感器为主。而对于化学量传感器而言，硅基上需要沉积敏感材料，由于硅基的表面光滑，使之与敏感材料的亲和性较差，造成敏感材料的附着结合性能较低，影响传感器的稳定性和可靠性，成功的案例还很少。因此，开展适用于毒气检测的化学量传感器的硅基芯片材料及微加工技术研究是很有必要的。本文针对硅基表面光滑，不易与气敏材料亲和，提出在硅基底上引入中间层纳米孔氧化铝膜形成新型硅基微结构传感器，通过ANSYS有限元仿真方法验证结构的合理性；开展基于铝膜的阳极氧化工艺，将纳米孔氧化铝膜移植到硅基表面；以聚苯胺与金属氧化物为源物质，采用原位化学聚合方法合成聚苯胺/无机物复合材料，通过理化分析手段进行表征；通过微加工工艺、薄膜工艺、电化学阳极氧化工艺、溶胶凝胶工艺、焊接工艺等制成MEMS气体传感器，分别以苯蒸汽、氨气和甲醛作为检测对象，进行了性能测试和分析，同时对其敏感机理进行探讨。研究的主要内容如下：1．设计新型硅基微结构芯片。在硅基微结构中引入一层纳米孔氧化铝膜中间层，利用其表面的多孔蜂窝状结构，增加基底与敏感材料之间的附着性。根据微加热器、信号电极和纳米孔氧化铝层的位置不同，设计四个方案。根据设计要求设计微热板的具体结构和尺寸，利用ANSYS有限元方法仿真计算各个方案中微结构的温度分布，根据仿真结果和结构的复杂程度选出最佳方案。2．进行聚苯胺/无机物复合敏感材料的合成及特性研究。聚合物/无机复合材料可在低温下使用，既可以发挥高分子聚合物气敏材料具有针对检测对象进行适当的改性、修饰、设计合成的特点，又可以综合无机材料的气敏响应特性，在一定程度上改善传感器的选择性、灵敏度、稳定性等各项指标。研究聚苯胺/无机物复合敏感材料合成及改性过程，通过扫描电镜、紫外可见光光谱、差热失重等理化分析手段对敏感材料进行表征分析，确定其工艺正确性及最终产物的基本特性。3．研究基于铝膜的阳极氧化工艺以及介孔内生长有机半导体的方法。在硅基底上通过磁控溅射和真空蒸发法制备铝膜，并通过电化学阳极氧化的方法制备成纳米孔氧化铝膜；研究铝膜成膜技术，电化学抛光、电解液种类和浓度、铝膜形成的方法等对纳米孔氧化铝膜的影响，以及纳米孔氧化铝膜的形成机理；通过溶胶凝胶法在纳米孔氧化铝膜表面形成敏感材料薄膜，并探讨形成机理。4．硅基微结构传感器的制备及测试。采用Fe/Cr/Al-Ni/Cr合金取代Pt电阻作为新的加热器材料，研究其制备工艺及加热特性。以半导体微加工工艺、薄膜工艺和电化学阳极氧化工艺为依托，制备新型硅基叠层微结构芯片。研究传感器对苯蒸汽、氨气和甲醛的检测方法，并分析传感器的气敏特性，探讨气敏机理。实验结果表明：基于铝膜的阳极氧化工艺可以成功将纳米孔氧化铝膜移植到硅基上，硅基微结构传感器中引入纳米孔氧化铝膜中间层，增加了敏感材料的附着性，合成的聚苯胺/无机物敏感材料对苯蒸汽、氨气和甲醛具有很好的气敏特性。更多还原

【Abstract】 People recognize gradually that indoor air pollution is sometimes morehazardous to human health than outdoor, how to take safety precautionary measuresto avoid the accident has become the safety issues of great concern to the state andsociety. Currently, there are some indoor air pollution detection methods, amongwhich sensor dectection method has the advantages of easy to use, direct readingwithout operation in addition to maintenance and correction, without professionaloperation, suitable for online testing. However, with the development of internet ofthings technology, traditional sensors can not meet the needs of the system becauseof lack of integration and embedding function, the height integration andcompatibility of the MEMS sensor bring hope to solve this problem.Si-based chip becomes a research hotspot of MEMS sensors, now the most ofSi-based MEMS sensors are pressure sensor, acceleration sensor, displacementsensor and other physical quantity sensors. And the successful chemical quantitysensors are few, because the smooth surface of the silicon and the poor affinitybetween silicon and sensitive material cause low adhesion binding property ofsensitive material, which affects the stability and reliability of the sensor. Therefore,it is necessary to research the silicon-based chip and micromachining technologysuitable for the chemical quantity sensor to detect toxic gas.In this paper, aiming at the problems of the smooth surface of the silicon and thepoor affinity between silicon and sensitive material, new silicon-based micro-structure sensor with nanoporous alumina membranes as the middle layer ispresented, and is verified the rationality of the structure by ANSYS finite elementsimulation method; the anodizing process of aluminum-based is carried out, and the nanoporous alumina membranes is migrated to the silicon surface; polyaniline andmetal oxides as the source material, polyaniline/inorganic composite materials aresynthesized through in-situ chemical polymerization method and characterized byphysicochemical analytical tools; MEMS gas sensor is made through micro-processing technology, thin film technology, electrochemical anodic oxidationprocess, sol-gel technology and welding technology, and the performance is testedand analyzed for benzene vapor, ammonia gas and formaldehyde gas respectively,and its sensitive mechanism is discussed. The main content was as follows:1. A new silicon-based micro-structure chip is designed. Nanoporous aluminumoxide layer is introduced in the silicon-based microstructure, and the poroushoneycomb structure of the surface increases the adhesion between the substrate andthe sensitive material. According to the different positions of micro-heater, signalelectrode and nanoporous alumina layer, four programs are designed, the concretestructure and sizes of the micro hot plate is designed based on the designrequirements, and the temperature distribution of the four micro-structures issimulated through ANSYS finite element method, and the best solution is electedaccording to the complexity of the structure and the simulation results.2. Polyaniline/inorganic composite sensitive materials are synthesized and theproperties are studied. Polymer/inorganic composite materials can work at lowtemperature, and both can play the features of polymer sensing materials withappropriate modification, modification, design and synthesis for detecting objects,and can integrate gas-sensitive response characteristics of inorganic materials, whichcan improve the selectivity, the sensitivity and stability of the sensor. The synthesisand modification process of PANI/inorganic composite sensitive materials arestudied, and composite sensitive materials are characterized by scanning electronmicroscopy, UV-visible spectroscopy and differential thermal analysis methods todetermine the validity of its process and the basic characteristics and the finalproduct.3. The aluminum-based anodizing process and a growth method of organicsemiconductor in mesopores are studied. The aluminum film is prepared on thesilicon substrate by magnetron sputtering and vacuum evaporation method, and madeinto nanoporous alumina membranes by electrochemical anodic oxidation method;the aluminum film preparative techniques, the effect of electrochemical polishing, the type and concentration of electrolyte and formation methods of aluminum on thenanoporous alumina membranes, and the formation mechanism of nanoporousalumina membranes are studied; the sensitive material film are formed on the surfaceof nanoporous alumina membranes through sol-gel method, and the formationmechanism is explored.4. The silicon-based micro-structure sensor is prepared and tested. Micro heateris made of Fe/Cr/Al-Ni/Cr alloy replacing Pt resistance, and its preparation processand heating characteristics are researched. A new Si-based stack micro-structure chipis prepared through semiconductor microfabrication technology, thin film technologyand electrochemical anodic oxidation technology. The sensor is detected for benzenevapor, ammonia gas and formaldehyde gas, its gas sensing characteristics is analyzed,and the gas sensing mechanism is discussed.The results of experiments show that: nanoporous alumina film has beensuccessfully transplanted on silicon substrate through anodic oxidation process of thealuminum film-based, the introduction of nanoporous alumina membranes into thesilicon-based micro-structure sensor increases the adhesion of the sensitive material,and polyaniline/inorganic sensitive materials synthesized have good sensitivity tobenzene vapor, ammonia gas and formaldehyde gas.更多还原