Fabrication and control of thin-film aluminum microheater and nickel temperature sensor

A thin film aluminum microheater and nickel temperature sensor are designed and fabricated by Micro Electro-Mechanical Systems (MEMS) for low temperature sensor and actuator applications. They are both constructed onto a glass substrate and covered with 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. K_p and K_i values are adjusted to obtain the optimal time response. Experimental testing of controlled temperature ranges from 40°C to 140°C are presented for their integration in stability system.