Miniaturized flow sensor with planar integrated sensor structures on semicircular surface channels

A calorimetric miniaturized flow sensor was realized with a linear sensor response measured for DI water flow from 40 nlmin^-1 up to 300 nlmin^-1. A versatile technological concept is used to realize a sensor with thermally-isolated freely-suspended silicon-nitride microchannels directly below the substrate surface. The microchannel concept allows for the planar integration of sensor structures in close proximity to the fluid. Chemical-resistant fluidic connections can be made directly on top of the microchannels, without introducing large dead-volumes. The realized flow sensor consists of a microchannel with low hydraulic resistance and small total fluid volume.