Research and fabrication of platinum thermal sensor based on intermittent etching method

For wet etching process of platinum, an intermittent etching method was put forward. Compared with etching along stirring method and static method, it was shown that the etched platinum had smooth curve and perfect effect by using intermittent etching method. Then, selecting silicon wafer as the substrate material and SiO₂ as the thermal insulating layer, platinum thermal sensors were fabricated by using the MEMS method mentioned above. Through thermal performance test, it was shown that the thermal sensor had TCR of 1571.2 × 10^-6/°C between 20 °C and 80 °C, uniformity of 0. 35%, non-linearity of 0. 57%, hot-time constant of 1. 1 μs, amplitude change of 0.005 Ω in the half-hour stability test, and the accuracy of 0.01%. The thermal sensor has high performance, and its fabrication process is simple. It can be used for temperature sensing,and gas sensing.