A Large-Range Graphene Pressure Sensor With Membrane-Beam Structure

A large-range graphene pressure sensor with a membrane-beam hybrid structure was designed and fabricated, and its measuring range could reach 200 MPa. The membrane made of high-strength alloy steel was used as the elastic element of the sensor. The graphene-based sensitive element was protected by Si3N4 and distributed at the root region of the silicon chip’s beam. The reliable connection between the steel membrane and the silicon chip was realized by solder bonding technology using Sn99Ag0.3Cu0.7. Scanning electron microscopy (SEM) microstructural analysis confirmed defect-free interconnection at the weld interface. Moreover, the results of SEM, Raman spectroscopy, and I–V tests showed that the graphene sensitive element has high quality and stable resistance. The pressure test indicated that the range of the sensor had achieved up to 200 MPa, the graphene gauge factor (GF) value is 1.27, and the sensitivity is 3.39 mV/MPa. According to comparation, this article has developed a large-range graphene pressure sensor, which will advancement facilitate the development and application of graphene in specialized fields, such as aerospace, industrial control, and the petrochemical industry.