Gas flow sensing with a piezoresistive silicon nanowire-based MEMS force sensor

Abstract

This paper introduces a novel flow sensor involving suspended piezoresistive silicon nanowires embedded in a MEMS platform. A highly linear response with a sensitivity of 6.26×10-4 (m/s)-1 is achieved within the velocity range of about 20 - 40 m/s. This translates to a very high sensitivity per effective sensing area, 7.37 ppm (m/s)-1 μm-2, and 1 nW power consumption, while operating over a velocity range similar to conventional bulky cantilever and diaphragm-based sensors. Further characterization performed at varying distances above the sensor surface demonstrates a spatial sensitivity of 4.90×10-3 mm-1. Sensor design enables high-density array operation where each MEMS unit acts as a force measurement pixel to analyze velocity gradients in various microfluidic flows with minimized power consumption and footprint. © 2025 IEEE.