A mems magnetic field sensor based on an in-plane stretchable mode resonator and its preparation method

Abstract

The invention discloses an MEMS (microelectromechanical system) magnetic field sensor based on contour-mode resonator and a preparation method thereof; a rectangular vibrator of a resonator is made with laminated magneto-electric composite and is supported by fixing beams at two ends over a hollow area of a silicon substrate; the rectangular vibrator comprises a bottom electrode layer, a piezoelectric layer, an adhesive layer, a low-resistance metal layer and a soft ferromagnetic alloy layer that are stacked in sequence from bottom to top; the bottom electrode is of comb tooth structure, extensions of the bottom electrode are extended to the outside silicon substrate along the fixing beams to connect an external circuit; at external extension ends of the bottom electrode, the piezoelectric layer is provided with via holes to expose a lower palladium electrode baseplate; a fixing beam portion of the vibrator is composed of the piezoelectric layer and the extensions of the bottom electrode; resonant frequency of the resonator is determined jointly by the vibrator material, film thickness and electrode size of the resonator; the magnetic sensor using the resonator can measure the amplitude of a magnetic field, is simple in structure, high in sensitivity and low in energy consumption, and is compatible with semiconductor manufacturing techniques.

Description

technical field [0001] The invention relates to the field of sensor technology and the field of micro-nano processing, in particular to a MEMS magnetic field sensor based on an in-plane stretchable mode resonator and a preparation method thereof. Background technique [0002] The application of magnetic field sensors not only has a long history, but also has a very wide range of application fields. From Sinan in the Spring and Autumn and Warring States Period to modern navigation, compass, position sensing, ferromagnetic material detection, current sensing, medical biological detection imaging, etc. Today, with the rapid development of electronic information technology, its application fields are still expanding. [0003] Many common sensors for measuring static magnetic fields utilize magnetic effects including: Hall effect, magnetoresitivity, fluxgate, induction, and static magnetic force. Various magnetic field measurement technologies have their own advantages and limi...

AI Technical Summary

Problems solved by technology

Therefore, the sensitivity of directly using the first-order effect of the magnetostrictive effect to induce the magnetic field in the low frequency band is limited to a certain extent.

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