High-sensitivity piezoelectric MEMS sensor and preparation method thereof

Abstract

The invention discloses a high-sensitivity piezoelectric MEMS sensor and a preparation method thereof. The piezoelectric MEMS sensor comprises a substrate and a piezoelectric stacking structure; the substrate is composed of a substrate bottom layer, a substrate intermediate layer and a substrate top layer from bottom to top; the substrate bottom layer is provided with a back cavity, and the substrate top layer is provided with regularly distributed hollow grooves; and the piezoelectric stacking structure is provided with a plurality of release holes penetrating through the piezoelectric stacking structure and communicating with the hollow grooves. According to the piezoelectric MEMS sensor of the invention, when the piezoelectric stacking structure, the substrate top layer and the substrate intermediate layer generate deformation, the flexural deflection of a piezoelectric film is increased due to the existence of the hollow grooves, the deformation degree of the piezoelectric film isenhanced, and a stronger electrical signal is output, so that the sensitivity of the piezoelectric sensor is improved.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to a high-sensitivity piezoelectric MEMS sensor and a preparation method thereof. Background technique [0002] As a transducer that converts mechanical energy and electrical energy, the sensor has been widely used in consumer electronics products such as mobile phones, computers, cameras, industry, life and health monitoring and other fields. Traditional sensors mainly include capacitive and piezoelectric sensors. The capacitive sensor adopts a double-layer film structure, and uses the principle of charging and discharging capacitance between conductors to change the voltage between conductors, thereby realizing the conversion of mechanical energy to electrical energy. Although the capacitive sensor has the advantages of a very wide frequency response range and fast instantaneous response, but the capacitive sensor is fragile, afraid of the tide and falling, and requires DC voltage...

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Problems solved by technology

[0003] At present, piezoelectric sensors are mostly made as cantilever beams or diaphragm structures. Although piezoelectric sensors have great advantages over capacitive sensors in terms of stability, waterproof and moisture resistance, and structural preparation, most piezoelectric materials are turned from blocks to The piezoelectric performance of the thin film material will decrease, and the dielectric loss will increase. In order to further improve the electromechanical coupling efficiency of the sensor, it is necessary to improve the piezoelectric sensor structure by optimizing the structure of the piezoelectric sensor or modifying the piezoelectric material. Sensitivity, thereby improving the performance of the sensor

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