Capacitive MEMS (micro-electromechanical system) pressure sensor

Abstract

A capacitive type MEMS pressure sensor, comprising a substrate (1), a detection thin film (2), an upper electrode plate (4) with a leading wire, and a lower electrode plate (3) with a leading wire. The detection thin film (2) is fixedly laid on an upper surface of the substrate (1). The upper electrode plate (4) is fixedly connected to the upper surface of the substrate (1) or the detection thin film (2). The upper electrode plate (4) is located above the detection thin film (2) and a gap (8) is formed between same and the detection thin film (2). The lower electrode plate (3) is fixedly arranged on the detection thin film (2). The lower electrode plate (3) is located in the gap (8) between the detection thin film (2) and the upper electrode plate (4). The lower electrode plate (3) and the upper electrode plate (4) constitute a capacitor. When a device is designed, the dimensions of the device can be more flexibly adjusted under specified device parameters so as to reduce costs. Moreover, the problem of changes in nonlinear and dynamic response ranges in the traditional pressure sensor is avoided in the structure of the device.

Description

technical field [0001] The invention relates to a pressure sensor, in particular to a capacitive MEMS pressure sensor. Background technique [0002] Capacitive pressure sensors are widely used due to their remarkable advantages such as low temperature drift, high sensitivity, low noise and large dynamic range. The contact capacitive pressure sensor is composed of a silicon diaphragm, a substrate, a substrate electrode and an insulating layer. A capacitive structure is formed between the silicon diaphragm and the substrate electrode; the silicon diaphragm is deformed after being subjected to pressure, and the electrode distance d changes accordingly. The MEMS capacitive pressure sensor includes two capacitors: one is the measurement capacitor C for measurement x , and the other is the reference capacitor C for temperature compensation o , when the diaphragm (upper electrode) is deformed when it is subjected to the pressure p, the distance between the diaphragm and the subs...

AI Technical Summary

Problems solved by technology

It can be seen that in order to improve the sensitivity of the traditional capacitive MEMS pressure sensor, it is realized by increasing the size of the detection film, reducing the thickness of the detection film and reducing the distance between the electrode plates, but this introduces nonlinearity and dynamic response of the device. Deterioration of range and other indicators; due to increased film size, further increase in device size and cost increase

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