A low-power embedded poly-Si micro-heater for gas sensor platform based on a FET transducer and its application for NO2 sensing

•A FET-type gas sensor platform with low power consumption is proposed.•The platform offers the best power efficiency (e.g. 300 ℃ at 1.63 mW) among the reported gas sensors with external heaters.•Electrode metals with low thermal conductivity and an efficient heat insulating air gap design improve power efficiency.•The platform is sensitive and advantageous for low-concentration gas detection. Gas sensors are commercialized and widely applied in various fields. Existing commercial sensors, however, have limitations in terms of power consumption. In this work, we propose a new design guideline of the FET-type gas sensor platform to significantly improve the power efficiency of the embedded poly-Si micro-heater. The fabricated sensors are capable of low power operation while maintaining high response and stability. To our knowledge, the embedded micro-heater of the proposed platform provides the best power efficiency (e.g. 300 ℃ at 1.63 mW) among reported gas sensors with external heaters. By adopting electrode metals with low thermal conductivity (Ti/TiN instead of Cr) in contact with the heater and an efficient heat insulating air gap design (increasing air gap length under the electrode from 0 μm to 28 μm), we can increase the heater temperature by 63 % at the same power consumption. Also, the proposed platform is more sensitive and advantageous for low-concentration gas detection compared to the reported FET-type platform using hot chuck that increases the temperature of the entire sensor.