A Microcantilever-based Gas Flow Sensor for Flow Rate and Direction Detection

TL;DR

This paper presents a MEMS-based microcantilever gas flow sensor capable of detecting both flow rate and direction by measuring resistance changes in silicon nitride cantilevers affected by residual stress and airflow-induced deformation.

Contribution

It introduces a novel microfabricated sensor design using residual stress-induced bending and resistance measurement for simultaneous flow rate and direction detection.

Findings

Successfully fabricated a four-cantilever sensor with perpendicular orientation.

Demonstrated flow rate measurement through resistance variation analysis.

Enabled flow direction detection by comparing resistance changes across cantilevers.

Abstract

The purpose of this paper is to apply characteristics of residual stress that causes cantilever beams to bend for manufacturing a micro-structured gas flow sensor. This study uses a silicon wafer deposited silicon nitride layers, reassembled the gas flow sensor with four cantilever beams that perpendicular to each other and manufactured piezoresistive structure on each micro-cantilever by MEMS technologies, respectively. When the cantilever beams are formed after etching the silicon wafer, it bends up a little due to the released residual stress induced in the previous fabrication process. As air flows through the sensor upstream and downstream beam deformation was made, thus the airflow direction can be determined through comparing the resistance variation between different cantilever beams. The flow rate can also be measured by calculating the total resistance variations on the four cantilevers.