A kind of capacitive pressure sensor and preparation method thereof

Abstract

The invention discloses a capacitive pressure sensor, including a SOI (Silicon-On-Insulator) silicon chip, a single crystalline silicon layer, a silicon dioxide layer and polysilicon layers. The SOI silicon chip is internally provided with a vacuum seal cavity. The silicon dioxide layer comprises with a first supporting layer, a second supporting layer and a third supporting layer which are identical in height and arranged in parallel. The first supporting layer is located in an upper area in the vacuum seal cavity. The second supporting layer and the third supporting layer are located outside of the upper area in the vacuum seal cavity. The second supporting layer is positioned between the first supporting layer and the third supporting layer. The polysilicon layers comprise a first polysilicon layer and a second polysilicon layer. The first polysilicon layer is fixedly connected on the first supporting layer and the second supporting layer. The second polysilicon layer is fixedly connected on the third supporting layer. One end surface of the first polysilicon layer is opposite to one end surface of the second polysilicon layer. The sensor has high efficiency and sensitivity in performance analysis. Meanwhile, the invention provides a preparation method of the sensor, and the preparation method is simple and easy to implement.

Description

technical field [0001] The invention relates to a pressure sensor, in particular to a capacitive pressure sensor and a preparation method thereof. Background technique [0002] Among the products realized by silicon micromachining technology, the pressure sensor is a relatively mature category. At present, pressure sensors have been widely used in various industrial and biomedical fields. Capacitive pressure sensors have gradually become a hot spot for pressure sensors due to their high sensitivity, better temperature performance, low power consumption, no temperature drift, firm structure, and little influence from external stress. Due to the small change in output capacitance of traditional capacitive pressure sensors, it is not conducive to pressure detection. It needs to amplify the change in output capacitance through subsequent processing circuits, which makes the processing circuits often more complicated. Therefore, the application of capacitive pressure sensors is ...

AI Technical Summary

Problems solved by technology

Due to the small change in output capacitance of traditional capacitive pressure sensors, it is not conducive to pressure detection. It is necessary to amplify the change in output capacitance through subsequent processing circuits, which makes the processing circuits often more complicated, so the application of capacitive pressure sensors is limited.

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