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Fabrication of micro gas sensor having micro gap electrode and its sensing properties to dilute gases

微间隙电极微型气体传感器的制作及其稀释气体传感性能

基本信息

批准号：
16550130
负责人：
TAMAKI Jun
金额：
$ 2.43万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16550130/
关键词：
Semiconductor gas sensor Micro gap electrode Tungsten oxide Nitrogen dioxide Indium oxide Chlorine gas Tin oxide Hydrogen sulfide

项目摘要

The micro-gap electrodes with various gap sizes (0.1-1.5 μm) were fabricated on SiO_2/Si substrate by means of MEMS techniques (photolithography and FIB). Then the oxide semiconductor thin films were deposited on the micro-gap electrode by using micromanipurator to be micro gas sensors. The effect of gap size on the gas sensitivity of semiconductor gas sensor was evaluated in the NO_2 sensing using WO_3 thin film microsensor, the Cl_2 sensing using In_2O_3 microsensor and the H_2S sensing using SnO_2 microsensor. The micro-gap effect was observed in all cases, i.e., the gas sensitivity was increased with decreasing gap size less than 1 μm. The micro gap effect was interpreted with the simple model and the gas sensitivity was divided into the sensitivity at oxide-electrode interface (S_i) and at grain boundary (S_<gb>). S_i was larger than S_<gb> in all cases. The contribution of oxide-electrode interface is increased when the gap size is decreased, and thus the sensitivity is increased … More with decreasing gap size. These results indicate the importance of oxide-electrode interface in semiconductor gas sensor and the nano-design of electrode structure for high sensitivity gas sensor. On the other hand, the extent of micro gap effect was different from each other in three sensing systems. The marked effects were observed for the NO_2-WO_3 and the Cl_2-In_2O_3 systems, while the H_2S-SnO_2 system showed small effect. The NO_2-WO_3 and the Cl_2-In_2O_3 systems showed the large S_i/S_<gb> ratio (32-43), while the small ratio (9.7) was obtained in the H_2S-SnO_2 system. It was found that the clearer micro-gap effect was obtained for the system having the larger S_i/S_<gb> ratio. NO_2 or Cl_2 molecules are negatively adsorbed on the oxide surface and the electrode surface to increase the sensor resistance, while H_2S molecule was oxidized on the oxide surface to consume adsorbed oxygen and to decrease the resistance. These differences in chemical process is considered to result in the different S_i/S_<gb> ratio. Less

采用微电子机械系统技术(光刻和离子轰击)在SiO_2/Si衬底上制备了不同间隙尺寸(0.1~1.5μm)的微间隙电极。然后在微隙电极上沉积氧化物半导体薄膜作为微气敏元件。在WO_3薄膜气敏元件、In_2O_3气敏元件和SnO_2气敏元件三种气敏元件中，研究了气隙尺寸对气敏特性的影响。在所有情况下都观察到了微间隙效应，即气体灵敏度随着间隙尺寸小于1μm而增加，用SIMPLE模型解释了微间隙效应，并将气体灵敏度分为氧化物-电极界面灵敏度(S_I)和晶界灵敏度(S_lt；GB&gt；)。S在所有情况下都比S大。随着间隙尺寸的减小，氧化物-电极界面的贡献增加，从而提高了…的灵敏度随着间隙大小的减小，变化更大。这些结果表明氧化物-电极界面在半导体气敏传感器中的重要性，以及高灵敏度气敏传感器电极结构的纳米设计。另一方面，在三种传感系统中，微间隙效应的程度也不同。NO_2-WO_3和Cl_2-In_2O_3体系的影响显著，而H_2S-SnO_2体系的影响较小。在NO_2-WO_3和Cl_2-In_2O_3体系中，S与S的比值较大(32-43)，而在H_2S-SnO_2体系中的比值较小(9.7)。结果表明，S/S比值越大，微隙效应越明显。NO2或Cl2分子被负吸附在氧化物表面和电极表面以增加传感器的电阻，而H_2S分子被氧化在氧化物表面以消耗吸附的氧气而降低电阻。这些化学过程的差异被认为是导致S/S的国标比率不同的原因。较少