Piezoelectric MEMS for vibrating sensing

Vibration sensors, also known as vibrometers, are essential components for maintaining the safety and reliability of various machines, such as aircraft engines. Vibrometers are capable of detecting very small vibrations, which can be caused by acceleration or pressure variations in the environment. However, the strict requirements for safety, resolution, endurance, and lifetime in the aerospace industry have caused the technology to evolve slowly. Indeed in this sector sensors have to work in harsh environments and at the same time high performances are required. MEMS-technologies based accelerometers were introduce to fulfill these requirements by substituting the old bulk technology: they are smaller, more responsive, more robust. In particular the current piezoelectric devices implemented for aerospace applications consist in boxes that contain a proof mass positioned on top of the piezoelectric material. This last one will be deformed due to the motion of the mass when the sensor is subjected to an acceleration. Therefore, the objective of this research project is to investigate the potential of piezoelectric MEMS based accelerometers as the next generation vibrometers. This work begins with a characterization of previous vibrometers to identify their strengths and limitations. Subsequently, the research focuses on the simulation, design, and fabrication of new devices that could potentially offer improved performance and greater reliability.