Measurement of reaction heats using a polysilicon-based microcalorimetric sensor

作者：Vereshchagina E^*; Wolters R A M; Gardeniers J G E

来源：Sensors and Actuators A: Physical , 2011, 169(2): 308-316.

DOI：10.1016/j.sna.2011.02.010

• Microcalorimeter
• Hot-plate
• Gas sensor
• Oxidation of alkanes
• Catalyst

In this work we present a low-cost, low-power, small sample volume microcalorimetric sensor for the measurement of reaction heats. The polysilicon-based microcalorimetric sensor combines several advantages: (i) complementary metal oxide semiconductor technology (CMOS) for future integration; (ii) elements of silicon micromachining (MEMS) to control thermal performance: (iii) heterogeneous catalysts for selective detection and analysis of individual gas compounds: and (iv) microfluidics for optimized control over the reaction conditions.
A comprehensive study on the electrical properties of polysilicon thin films as a potential material for temperature monitoring of highly exothermic reactions is presented. Resistive measurements were performed up to 800 degrees C and a temperature coefficient of resistance (TCR) of 3.24 x 10(-4)/degrees C was derived in the quasi-linear resistive range between 300 and 500 degrees C. The polysilicon thin film temperature sensors show a good stability. Due to its excellent compatibility with silicon technology and chemical inertness, doped polysilicon thin films can be successfully applied in catalytic microreactors and sensor microsystems at high operating temperatures.
We demonstrate the performance of polysilicon sensors by the detection of reaction heats for a model reaction - the catalytic oxidation of propane in air at concentrations in the range of 0.01-0.8 vol.% which is below the low explosion level (LEL) of propane of 2.1% [1]. The sensor exhibits immediate and reversible response upon exposure to propane in air. By choosing a selective catalyst the specificity of the sensor can be tuned to different gases.

• 出版日期2011-10