Piezoresistive micro-cantilever beam sensor based on suture stress concentration and manufacture method

Abstract

The invention discloses a piezoresistive micro-cantilever beam sensor based on hole slot stress concentration and a method for preparing the same. A sensing unit consists of two micro-cantilever beams and four identical piezoresistors which form a Wheatstone bridge; middle oxidation layers of SOI silicon slices are used as the main bodies of the cantilever beams; one of the cantilever beam is used as a detection cantilever beam which is etched with three rectangular hole slots as stress concentration regions; the other cantilever beam is used as a reference cantilever beam which is not processed with a hole slot structure; two of the piezoresistors are arranged on the two cantilever beams; and the other two piezoresistors are positioned on the silicon slices. The invention can greatly improve the sensitivity for the stress detection of the micro-cantilever beam sensor, and maintain a higher measuring bandwidth. The invention can be applied to various piezoresistive type MEMS structures such as force sensor, micro-gyroscope, resonator and the like, and can be applied to the fields of environmental detection, food safety, aerospace and military and the like.

Description

technical field [0001] The invention relates to a sensor and a preparation method thereof, in particular to a piezoresistive micro-cantilever beam sensor and a preparation method based on the stress concentration of a slit structure. technical background [0002] In recent years, sensors based on micro-cantilever structures have become a research hotspot in the field of micro-electromechanical systems. This type of sensor has the characteristics of high sensitivity, high resolution, fast response and miniaturization, and is widely used in the fields of biochemical sensing and detection. There are optical and electrical methods for measuring the bending of a microcantilever. The optical method has high sensitivity, but the system is complicated, and the optical system requires precise calibration, which limits its wide application. The electrical method includes piezoresistive, piezoelectric, capacitive, etc., and its sensitivity is lower than that of the optical method, but...

AI Technical Summary

Problems solved by technology

For the piezoresistive micro-cantilever sensor, a cantilever made of a material with a smaller Young's modulus (the middle silicon dioxide layer of the SOI silicon wafer has a smaller Young's modulus than single crystal silicon, etc.) under the same conditions Large bending stress will be generated, and usually the piezoresistive micro-cantilever adopts single crystal silicon or silicon nitride material with relatively large Young's modulus, which is not conducive to large bending deformation

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