Micro mechanical differential capacitive pressure gauge

Abstract

The invention discloses a micro mechanical differential capacitive pressure gauge. Two capacitors of the pressure gauge are formed by three capacitive polar plates: an upper polar plate formed through depositing a metal on a glass sheet or a silicon wafer; a lower polar plate formed by heavily doped silicon and an intermediate movable polar plate which is partly connected with a pressure-sensitive membrane and formed by monocrystal silicon or polycrystalline silicon. The pressure gauge is based on a basic silicon cup structure in a pressure gauge structure, when a pressure is applied to the sensitive membrane, the membrane is deformed and the intermediate polar plate connected with the sensitive membrane is also deformed so that the capacitances of the upper and lower capacitors are changed and thus differential signal output is formed. The preparation process of the pressure gauge is simple and advantages of a differential structure can be used to realize differential detection of pressure.

Description

technical field [0001] The invention relates to the technical field of MEMS (micro-electro-mechanical systems) differential capacitive pressure gauges. Background technique [0002] Capacitive structures are widely used in the field of microsensors. Compared with piezoresistive structures, capacitive structures have lower temperature coefficients. Capacitive structures have the advantages of low power consumption, high sensitivity, simple structure, and good dynamic characteristics. , so the capacitive sensor is considered to be a promising sensor. However, due to the nonlinearity of the capacitive sensor itself, the detection of tiny capacitance is susceptible to the influence of parasitic capacitance and the interference of the environmental electromagnetic field. The capacitive sensor did not make great progress until the 1980s. The first silicon capacitive pressure sensor was reported by Ford Motor in 1979. Since then, many companies, universities and scientific researc...

AI Technical Summary

Problems solved by technology

[0018] In 2003, Dae-Sung Lee of South Korea published a patent US6,651,506 B2, which introduced two possible structures of a differential capacitive pressure gauge. The capacitive pressure sensor can realize differential detection of pressure, but realizes There are still some difficulties in the process

[0020] At present, there are few research results on differential capacitance manometers, mainly the combination of variable capacitance and reference capacitance to detect differential pressure, or some achievements only in structural design, simple process, strict differential capacitance manometer There are very few reports

Images