A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection
A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection
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DOI：
10.1016/j.snb.2006.06.018
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发表时间：
2007-03-26
影响因子：
8.4
通讯作者：
Ma, Rong-Hua
中科院分区：
文献类型：
--
作者：
Lee, Chia-Yen;Chiang, Che-Ming;Ma, Rong-Hua
本研究开发了一种基于悬浮氮化硅微结构的MEMS甲醛气体传感器，该传感器集成了微型铂加热器、薄膜NiO敏感层和铂交叉指电极(IDES)，用于测量NiO层在甲醛存在下的电阻变化。在溅射过程中，随着衬底温度的升高，NiO层有特定的取向。衬底温度的升高有助于形成具有正确化学计量比(1：1)的NiO层。当大气中存在甲醛时，氧化发生在加热的NiO敏感层附近。这种氧化导致NiO膜的电导率发生变化，从而改变了交错电极之间的测量电阻。然后根据测量的电阻的变化来确定甲醛浓度。在铂加热器上施加电压会导致微热板的温度升高，进而提高传感器的灵敏度。目前的实验结果表明，所制备的亚微米级氧化物薄膜具有较高的灵敏度(0.33Omega ppm(-1))、低滞后(0.7ppm)、小于0.8ppm的检测能力、快速的响应时间(13.2Oppm)、快速的恢复时间(40.0S)以及在丙酮、乙醇和甲醇等干扰物种存在的情况下对多种甲醛浓度的高选择性。本研究开发的新型微型甲醛气体传感器非常适合用于预防和控制病态建筑综合症(SBS)的应用。(C)2006爱思唯尔B.V.保留所有权利。
This study develops a MEMS-based formaldehyde gas sensor based on a suspended silicon nitride microstructure with an integrated micro Pt heater, a thin-film NiO sensing layer and Pt interdigitated electrodes (IDEs) to measure the resistance changes of the NiO layer in the presence of formaldehyde. A specific orientation of the NiO layer is observed as the substrate temperature in the sputtering process is increased. The increase in substrate temperature assists in the formation of a NiO layer with the correct stoichiometric ratio (1:1). When formaldehyde is present in the atmosphere, oxidation occurs near the heated NiO sensing layer. This oxidization causes a change in the electrical conductivity of the NiO film, and hence changes the measured resistance between the interdigitated electrodes. The formaldehyde concentration is then determined from the change in the measured resistance. The application of a voltage to the Pt heaters causes the temperature of the micro-hotplate to increase, which in turn enhances the sensitivity of the sensor. The current experimental results show that the sub-micrometer grain sizes of the sputtered oxide thin film yield a high degree of sensitivity (0.33 Omega ppm(-1)), a low hysteresis value (0.7 ppm), a detection capability of less than 0.8 ppm, a quick response time (13.2 s), a quick recovery time (40.0 s) and a high selectivity over a wide range of formaldehyde concentrations in the presence of interfering species, such as acetone, ethanol and methanol. The novel micro formaldehyde gas sensor developed in this study is ideal for applications aimed at preventing and controlling sick building syndrome (SBS). (c) 2006 Elsevier B.V. All rights reserved.