Observation of flexoelectric effect in PECVD silicon nitride

Flexoelectricity, a universal electromechanical coupling effect present in all dielectric materials, has garnered significant theoretical and experimental interest in recent years, particularly in ferroelectric perovskite oxides. However, nitride-based materials have received considerably less attention. In this Letter, we report the observation of direct flexoelectric effect in plasma-enhanced chemical vapor deposition silicon nitride thin film with a thickness of 200 nm. From three-point bending tests, we determined the effective flexoelectric coefficient of Si3N4 to be 1.64±0.22 nC/m. Additionally, the measured flexoelectric-induced voltages are consistent with finite element computational models. This observation of the flexoelectric coupling effect could contribute to the development of silicon nitride-based micro-scale devices.