Design and fabrication of thin-film aluminum microheater and nickel temperature sensor

This paper presents development of a thin film aluminum microheater and a nickel temperature sensor for low temperature applications by using Micro-Electro-Mechanical Systems. Both of them are fabricated onto a glass substrate and protected by thin PDMS membrane. The microheater is energized to find sensor characteristic. As linearity and accuracy of nickel sensor give a wide temperature range, its electrical resistance variations are calibrated directly by temperatures of energized microheater. Variations of resistance signal are transformed and fed back to control temperature of microheater in PI closed-loop feedback control. Kp and Ki values are adjusted to obtain the optimal time response. Experimental testing of controlled temperature ranges from 40°C to 140°C is presented for their integration in stability system.