Multi-operation-mode piezoelectric viscosity sensor chip and working method and preparation method thereof

Abstract

The invention discloses a multi-operation-mode piezoelectric viscosity sensor chip and a working method and a preparation method thereof. The multi-operation-mode piezoelectric viscosity sensor chip comprises a silicon substrate and a silicon micro-cantilever resonator. The silicon micro-resonance cantilever beam structure is covered with a low-stress aluminum nitride piezoelectric film through anMEMS process. The double piezoelectric electrodes can be used for introducing alternating voltages with a certain frequency and generating a piezoelectric driving force by utilizing an inverse piezoelectric effect; a vibration signal of the silicon micro-cantilever resonator can also be converted into a detectable voltage signal through a piezoelectric effect; four sensitive piezoresistive stripson four piezoresistive beams form a Wheatstone full bridge through metal leads on piezoresistive connecting beams so as to detect resonance stresses and convert the resonance stresses into voltage signals for output. An in-plane vibration mode of the cantilever beam resonator can be obtained through a piezoelectric excitation mode, a piezoelectric and piezoresistive double-detection mode is adopted for output of vibration electric signals. The viscosity sensor chip has high-quality factors in fluid, and the application range and the measurement precision of fluid viscosity can be remarkably improved.

Description

technical field [0001] The present invention relates to the field of MEMS (Micro Electromechanical Systems, micro-mechanical electronic systems) sensors, and more specifically, relates to a multi-operation mode piezoelectric viscosity sensor chip and its working method and preparation method. Background technique [0002] The resonant viscosity sensor chip based on MEMS technology detects the viscosity characteristics of the fluid, relying on the change of the resonant frequency and quality factor of the resonator caused by the change of the additional mass of the attached fluid molecules and the change of the viscous force. Compared with the traditional viscometer, it has a small volume , easy operation, high sensitivity and other superior measurement performance. However, the fluid viscosity has a non-negligible influence on the quality factor of the MEMS resonant viscosity sensor chip. The medium-high viscosity fluid produces significant fluid viscous damping on the visco...

AI Technical Summary

Problems solved by technology

However, the fluid viscosity has a non-negligible influence on the quality factor of the MEMS resonant viscosity sensor chip. The medium-high viscosity fluid produces significant fluid viscous damping on the viscous resonator immersed in it. It will significantly reduce the quality factor of the resonator, reduce the vibration stability of the resonator, and make the MEMS viscosity sensor chip face key problems such as narrow application range, low precision, and poor convenience.

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