A micromachined gas sensor based on a catalytic thick film/SnO₂ thin film bilayer and thin film heater: Part 1: CH₄ sensing

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• 作者：Takuya Suzuki ; Kenji Kunihara ; Mitsuo Kobayashi ; Soichi Tabata ; Katsuki Higaki and Hisao Ohnishi
• 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：185-189
• 文件大小：259 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 CH₄ 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 a Si micromachined structure having a silicon oxide–silicon nitride membrane. On the SnO₂ sensing layer, a Pd–Al₂O₃ catalytic thick film was formed to oxidize interfering gases selectively. The sensor realized low power consumption and fast thermal response due to the low thermal conductance and the small heat capacity of the membrane. The power consumption at an operating temperature of approximately 450 °C was 30 mW. The sensitivity (R_air/R_gas) to 2000 ppm CH₄ in air was greater than 5, while the sensitivity to H₂, an interfering gas, was relatively low.