A Novel Crossbeam Structure with Graphene Sensing Element for N/MEMS Mechanical Sensors

A graphene membrane acts as a highly sensitive element in a nano/micro-electro-mechanical system (N/MEMS) due to its unique physical and chemical properties. Here, a novel crossbeam structure with a graphene varistor protected by Si₃N₄ is presented for N/MEMS mechanical sensors. It substantially overcomes the poor reliability of previous sensors with suspended graphene and exhibits excellent mechanoelectrical coupling performance, as graphene is placed on the root of the crossbeam. By performing basic mechanical electrical measurements, a preferable gauge factor of ~1.35 is obtained. The sensitivity of the graphene pressure sensor based on the crossbeam structure chip is 33.13 mV/V/MPa in a wide range of 0~20 MPa. Other static specifications, including hysteresis error, nonlinear error, and repeatability error, are 2.0119%, 3.3622%, and 4.0271%, respectively. We conclude that a crossbeam structure with a graphene sensing element can be an application for the N/MEMS mechanical sensor.