A MEMS multi-sensor chip for gas flow sensing

This paper reports the development of a MEMS multi-sensor chip that enables the simultaneous measurements of shear stress, pressure, and temperature inside microchannels. On the multi-sensor chip, five sensor clusters, which consist of shear-stress, pressure, and temperature sensors, are arranged in a one-dimensional array. The multi-sensor chip has been characterized in a rectangular microchannel using both incompressible and compressible gas flows. A simple normalization method has proven to be effective in the reduction of the sensitivity variation of the shear-stress sensors. It has also been found out that the classical theory for conventional hot-film sensors needs to be modified for the MEMS thermal shear-stress sensors. Furthermore, flow rate measurements based on both differential pressure and thermal anemometry principles have been demonstrated using the multi-sensor chip.