Development and application of microthermal sensors with a mesh-membrane supporting structure

Abstract

The design, fabrication, and application of microthermal sensors are presented in this work. The working principle of the microthermal sensor is thermistor, using platinum as the sensing material. A new mesh-membrane structure is presented. This design can reduce the etching time and still provide stiff-enough suspension. The fabrication of the mesh-membrane is timesaving and wastes less material because the back-side etching processes are avoided. The fabricated thermal sensor has flat surface, a sensitivity of 3.263°C/mW, and a response time of less than 5 ms. In addition, one-wire type thermal flow sensors based on this kind of microthermal sensor are designed and fabricated. For the flow velocity higher than 1.5 m/s, the sensitivity of the flow sensor operating in the constant-voltage mode is above 0.01433 mA (m/s)- 1/2, with power consumption of 14.56 mW, and is above 7.98 mV (m/s)- 1/2 in the constant-current mode, with power consumption of 45.10 mW.