Accurate temperature extraction of embedded polysilicon micro-heaters

초록

Accurate temperature estimation of the embedded micro-heater is critical for the reliable operation and data interpretation of FET-type gas sensors. In this work, the length-resolved temperature extraction method is proposed to improve heater temperature estimation by separating contact and sensing region related resistance contributions. Polysilicon micro-heaters with different sensing region lengths enable independent extraction of the absolute temperature sensitivities of the contact and sensing regions. Using these temperature sensitivities, the contact temperature (TC) and sensing region temperature (TS) are separately estimated. COMSOL simulations confirm the distribution of temperature and the physical basis of the proposed decomposition. Quantitative comparison with simulation results demonstrates that the proposed TS provides a more accurate estimation of the sensing region temperature than the conventional RTD (resistance temperature detector)-based temperature TRTD, maintaining a good agreement up to operating temperatures of 240 degrees C. Finally, NO2 sensing results verify that the proposed method enables consistent and accurate temperature extraction across devices with different heater structures. These results confirm that length-resolved resistance analysis provides an effective and practical approach for accurate temperature estimation.

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