Thermal analysis of a planar-type micro gas-sensor by using a finite element method

A new planar-type micro gas-sensor in which a gas-sensing layer is surrounded by a platinum heater horizontally on the plane of the diaphragm is proposed. The proposed structure simplifies the fabrication process, is suitable for forming a gas-sensing layer when using wet processes like spin coating, and provides temperature uniformity over the sensing layer. Thermal analyses of the proposed planar structure, including the temperature distribution over the sensing layer and the power consumption of the heater, were carried out by using a finite element method, and the results compared well with those for a typical stack-type micro gas-sensor. The thermal properties of the microsensor, which were obtained from a thermal simulation, were verified by fabricating and analyzing an actual device.