基于叉指电极的气体传感器的特性及加工研究

发布时间：2018-05-13 06:43

本文选题：叉指电极MEMS + 气体传感器　；参考：《成都理工大学》2017年硕士论文

【摘要】：当下,环境污染情况愈演愈烈,特别是一些有毒、有害气体无时无刻不威胁着我们的健康。那么如何精准、快速、便利地检测到诸如此类的气体,就变成了一项十分艰巨而又极其重要的工作。当然,目前检测手段多样,但半导体气敏传感器凭借其体积小、恢复时间短以及重复使用性好等诸多优点,而受到广泛关注。不尽如人意的是,目前成品化的半导体气体传感器仍有些欠缺,如选择性差、响应度低、工作温度偏高等,这就使得半导体气体传感器的应用拓展举步维艰。基于此,本文将半导体气体传感技术与MEMS制造工艺进行有效联合,制备叉指电极传感器,并利用氨气、二氧化氮、甲醛以及丙酮检测了基于叉指电极的气体传感器的气敏特性。实验结果表明,本文中制备的基于叉指电极的气体传感器,气体响应灵敏度较高、响应恢复时间较快、工作温度也较低。具体内容如下:首先,本文阐述了叉指电极气体传感器的基本原理,并且建立了叉指电极极间电阻的计算模型,分别用精确的计算方法以及忽略尖端电场,计算了其极间电阻。通过分析得到:用叉指电极制成的传感器,当叉指的宽长比越小,叉指的密度越大,所制备的叉指电极的极间电阻就会越小,用它制成的传感器的灵敏度和响应速度就会越高。基于此,结合实验室现有条件,设置了叉指电极的各个参数,其中:a为50μm,b为50μm,c为150μm,d为20000μm。长宽比选择400,叉指电极对数一共50个周期。其次,选择硅作为叉指电极的衬底材料,通过硅片清洗、二氧化硅生长、紫外光刻等工艺,成功制备了叉指电极传感器,并将三氧化钨浆料与叉指电极进行完美整合,制备出了叉指电极气敏元件。最后,将该叉指电极传感器对4种常见污染物气体的气敏特性进行了检测。实验结果表明:在100ppm氨气中,工作温度为200℃时,叉指电极传感器拥有最高灵敏度,达43.1,响应恢复时间大约为5s;在100ppm二氧化氮气体中,最佳工作温度为250℃,此时灵敏度达94.9,响应恢复时间大约为4s。在100ppm的甲醛与丙酮环境中,工作温度为50℃的叉指电极传感器,灵敏度分别达到16.8与4.8。工作温度的升高,对甲醛的灵敏度影响较小,而对丙酮的影响很大。在响应-恢复时间方面,在50℃测量甲醛时,其响应和恢复时间各为5s、26s,在同等前提下,丙酮的响应和恢复时间则各为5s、24s。
[Abstract]:At the moment, the environmental pollution is becoming more and more intense, especially some poisonous, harmful gases that threaten our health all the time. Then how to accurately, quickly and conveniently detect such gases has become a very arduous and extremely important work. Because of its small size, short recovery time and good reusability, it has attracted wide attention. It is not satisfactory that the finished semiconductor gas sensors are still lacking, such as poor selectivity, low response and high working temperature, which makes the application of semi conductor gas sensors difficult. Based on this, In this paper, the semiconductor gas sensing technology is effectively combined with the MEMS manufacturing process to prepare the cross finger electrode sensor, and the gas sensing characteristics of the gas sensor based on the cross finger electrode are detected by the ammonia, nitrogen dioxide, formaldehyde and acetone. The experimental results show that the gas sensor based on the interdigital electrode and the gas response spirit in this paper have been prepared in this paper. The sensitivity is higher, the response time is faster and the working temperature is low. The main contents are as follows: firstly, the basic principle of the interdigital electrode gas sensor is expounded, and the calculation model of the interdigital resistance of the interdigital electrode is set up, and the interpolar resistance is calculated with the accurate calculation method and the neglecting the tip electric field. The sensor made with a cross finger electrode, when the width of the finger is smaller, the greater the density of the finger, the smaller the resistance of the interdigital electrode will be, the higher the sensitivity and response speed of the sensor made with it. Based on this, the parameters of the interdigital electrode are set up in the laboratory conditions, including a 50 m, B is 50 M, C is 150 mu m, D is 20000 M. long width ratio selection 400, and the cross finger electrode is 50 cycles. Secondly, silicon is selected as the substrate material of the cross finger electrode. Through silicon wafer cleaning, silicon dioxide growth and UV photolithography, the cross finger electrode sensor is successfully prepared, and the tungsten trioxide size and the cross finger electrode are perfectly integrated and prepared. At last, the cross finger electrode sensor was used to detect the gas sensitivity of 4 kinds of common pollutants. The experimental results showed that when the working temperature was 200, the cross finger electrode sensor had the highest sensitivity of 43.1, the response time was about 5S, and in the 100ppm nitrogen dioxide gas. The good working temperature is 250 C, at this time the sensitivity is 94.9, the response time is about 4S. in the 100ppm formaldehyde and acetone environment, the working temperature is 50 degrees centigrade, the sensitivity is up to 16.8 and 4.8., and the sensitivity of formaldehyde is little, but the effect on acetone is great. In response recovery time In terms of formaldehyde and reaction time at 50 C, the response time and recovery time were 5S, 26S. Under the same conditions, acetone response and recovery time were 5S, 24s. respectively.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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