陶瓷微热板气体传感器阵列快速响应机制及微观失稳特性研究

This project will aim at the instability characteristics of gas sensor array under the rapid detection technology of the poisonous and noxious gases like CO、SO2、NOx、O3 exsiting in the current atmospheric haze. Since the semiconductor gas sensor array has the disadvantages of slow response, poor stability and sensitive to environmental interference, the ceramic microhotplate gas sensor array with good thermal stability and self-thermal isolation, is designed and developed, exploring the AlN/Al2O3 materials as a substrate which have excellent mechanical and thermal properties. The microscopic scale effect and heat-transfer mechanism of microhotplate sensor array are studied, and the thermal interference characteristics among sensor array units are analyzed. In addition, the coupling instability characteristics of electric, thermal and force fields for multilayer dielectric films are investigated in micro-scale, and then the thermal transient response model with time scale is built. The effects of the electrothermal coupling efficiency, transport and scattering mechanism of electron and phonon on the response rate and instability characteristics are revealed. The temperaute modulation effect is studied in order to establish the optimum operating temperature and response rate for the pulse temperature modulation frequency and sampling frequency. Thus, the optimization and improvement of sensor array can be realized from the structure size design, preparation process and detection method, which will effectively solve the existing problems in the rapid response mechanism and instability for gas sensor array, and hence the detection rate and the capability of anti-environmental disturbance of gas sensor array can be enhanced greatly in atmospheric environment.

本项目是以大气污染下典型有毒有害气体CO、SO2、NOx、O3等快速检测技术中传感器的失稳特性为研究目标，针对目前半导体气体传感器及阵列检测技术存在响应慢、稳定性差、易受环境干扰等共性缺点，提出采用具有良好机械性能和热性能的AlN/Al2O3作介质膜和衬底，设计并制备陶瓷微热板传感器阵列为研究平台。研究微热板传感器阵列微观尺度效应、微传热机制及阵列单元之间的热干扰特性。研究微观尺度下多层异质膜电/热/力多场耦合失稳特性，建立热瞬态响应时间尺度依赖关系模型，揭示电子、声子的电热耦合效率、输运及散射机制对响应速率及失稳特性的影响机理。在检测上研究温度调制效应，确立脉冲温度调制频率与幅值对最佳工作温度及响应速率影响特性。从而实现传感器阵列结构尺度设计、工艺制备及检测方法优化与改进，有效解决气体传感器阵列的快速响应机制和失稳问题，提高复杂大气环境下传感器阵列气体检测速率及抗环境干扰能力。

大气污染对人类健康和工农业生产影响至关重要，本项目针对复杂大气污染中典型有毒有害气体传感器检测性能问题，开展了基于陶瓷微热板气体传感器阵列快速响应机制及微观失稳特性研究。首先从硅基和非硅基工艺角度讨论分析了微热膜型、微热桥型和微热岛型三种微热板气体传感器微尺度结构及热力学特性，优化设计并制备了基于AlN/Al2O3复合陶瓷衬底的微热板集成四阵列气体传感器，并对所设计的传感器阵列结构进行热梯度和热应力有限元仿真实验分析论证。其次突破MEMS工艺技术制备了陶瓷基微热板传感器及阵列芯片，研究了非硅基光刻剥离工艺的可移植性，提出了柔性机械光刻剥离工艺法，解决了陶瓷基普通正性光刻胶剥离难的问题。针对阵列单元间的热响应速率和热失稳问题，建立了热干扰和热失稳理论模型，并提出通过在衬底施加加高导热率介质膜结构，提高热响应速率，通过激光刻蚀热隔离设计，降低热干扰及热损耗影响，提高了热稳定性，并在工艺制备中得到可行性实施和验证，并为微热板气体传感器及阵列设计与制备提供了有效关键技术。最后针对复杂大气污染气体CO、NO2、SO2等有毒有害气体进行了稳态热性能测试和静态气敏测试，达到了良好的气敏检测性能，在分辨率和低浓度检测极限上有待进一步提高，验证了所制备陶瓷微热板设计的合理性和实施工艺的可行性。在研究传感器阵列静态气敏检测的同时，针对复杂环境下低浓度有毒有害气体的交叉敏感的检测难题，探索研究了一种动态低频温度调制检测方法，提高了CO和CH4气体的选择性，为下一步利用温度调制检测参量的多样性，构建特征信号的多样性，结合有效检测方法和智能算法为大气污染气体传感器阵列电子鼻识别开辟效解决途径。.在本项目资助下，共发表论文10篇，其中EI/SCI检索7篇，中文核心期刊3篇；授权专利5项，其中发明专利3项，参加学术及交流会议3次；指导学生科技竞赛获省级及以上奖励6次；并培养了三名研究生，其中1人获国家奖学金。