A micromachined gas sensor based on a catalytic thick film/SnO₂ thin film bilayer and a thin film heater: Part 2: CO sensing

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• 作者：Soichi Tabata ; Katsuki Higaki ; Hisao Ohnishi ; Takuya Suzuki ; Kenji Kunihara and Mitsuo Kobayashi
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2005
• 期刊代码：161_09254005
• 类别：et
• 出版时间：2005
• 卷：109
• 期：2
• 页码：190-193
• 文件大小：202 K

摘要

A micromachined gas sensor based on a catalytic thick film/SnO₂ thin film bilayer and a thin film heater was investigated for CO sensing. The sensor demonstrated good sensitivity and high selectivity with low power consumption.

The thin film heater and the SnO₂ thin film sensing layer were deposited on an Si micromachined structure having a silicon oxide–silicon nitride membrane. On the SnO₂ sensing layer, a Pd-Al₂O₃ catalytic thick film was formed to promote CO detection with a catalyst.

The sensor realized low power consumption and fast thermal response owing to small heat capacity. This fast thermal response decreased the time required to detect CO and thus decreased the time to operate the sensor. The average power consumption was less than 0.03 mW when operated every 2 min. The sensor sensitively detected CO by high-and-low periodic operation of the heater, while the sensitivity to H₂, the interfering gas used, was relatively suppressed.