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.