Nickel membrane temperature sensor in micro-flow measurement

According to the principle of the thermal distribution pattern, a microfluidic sensor based on silicon was fabricated with the microelectronic technique and the micro electro-mechanical systems (MEMS) process, including a micro-heater and two temperature sensors. NiCr and Ni thin films were chosen as the materials of the micro-heater and the temperature sensors, respectively. The Ni membranes were deposited on different substrates, and the adhesion between Ni thin film and different substrates was investigated by electron probe micro analyzer (EPMA). The thermal characteristics of the nickel thin film fabricated on different substrates were measured. The results indicate that Si3N4 and SiO2 are more suitable than Si to be used as the substrate for fabricating the temperature sensor. The temperature sensors satisfied the requisition of fast response and high sensitivity, and the microfluidic sensor fabricated in this paper will have much hope of using in biochemical analytical system. (c) 2006 Elsevier B.V. All rights reserved.