Offset compensation of integrated thermal flow sensors by means of split heater microstructures

The effectiveness of a new offset compensation technique for integrated thermal flow meters is demonstrated. A sensor structure based on two heaters placed between two temperature probes is designed with a commercial CMOS process and fabricated by means of a post-processing technique. The power unbalance between the two heaters is used to compensate the intrinsic sensor offset. Experiments, performed in nitrogen at different temperatures, confirm the reduction of both offset and its temperature drift by nearly one order of magnitude.