MEMS cylinder-type high-temperature and superhigh-pressure resistant sensor

Abstract

An MEMS (Micro-electromechanical System) cylinder-type high-temperature and superhigh-pressure resistant sensor comprises a base; a silicon beam sensation element is encapsulated on a side plane surface of a pressure-bearing cylinder at the upper part of the base, and a measuring island of the element is in contact with a side surface of the pressure-bearing cylinder; the pressure-bearing cylinder is provided with a high-temperature switching terminal; a Wheatstone bridge of the silicon beam sensation element is connected with the high-temperature switching terminal; a high-temperature cable conductor connected with the high-temperature switching terminal is connected with an external circuit; to-be-measured pressure acts on the pressure-bearing cylinder to cause expansion deformation to the circumference of the pressure-bearing cylinder, and the maximum deformation eccentricity in the radial direction is transmitted to the measuring island, so that the silicon beam is caused to deform, and the resistance values of four varistors of the Wheatstone bridge change; constant current or constant voltage is loaded into the input terminal of the bridge through a high-temperature cable wire, the high-temperature switching terminal and a gold wire lead; and the bridge outputs electrical signals in direct proportion to the to-be-measured pressure and transmits the signals to the external circuit, so that the to-be-measured pressure can be measured. The invention has the advantages of large measurement range, wide range of application, good sensitivity, high signal-to-noise ratio, and good temperature stability.

Description

Technical field: [0001] The invention relates to a pressure sensor, in particular to a MEMS cylinder-type high-temperature resistant ultra-high pressure sensor. Background technique: [0002] Today's petrochemical, aerospace, military, smelting and other fields generally have measurement problems under high temperature, instantaneous high temperature shock, ultra-high range and other conditions. The high temperature resistant pressure sensor designed for this measurement problem has been extensively researched and applied. Such as SOI silicon piezoresistive pressure sensor, SOS pressure sensor, sputtering film pressure sensor, and high temperature resistant pressure sensor made of silicon strain gauge or high temperature foil strain gauge, etc. From the perspective of measurement mechanism, these sensors are based on the resistance effect; from the perspective of structure, the elastic elements and sensitive elements of these sensors can be divided into two types: integrated...

AI Technical Summary

Problems solved by technology

[0003] The SOI piezoresistive pressure sensor with the integrated structure of the elastic sensitive element has the following disadvantages: 1) the maximum range does not exceed 150MPa; 2) the measured medium must not only be compatible with the shell material, but must also be compatible with silicon, glass and packaging materials, so The scope of application is relatively narrow

[0004] The high-temperature-resistant pressure sensor with a combined structure of the elastic element and the sensitive element has the following disadvantages: 1) The sensitive element is packaged on the metal elastic element through various processes, and the sensitive element senses the strain of the metal elastic element to achieve the purpose of detecting pressure

However, the differences in thermal expansion coefficients of sensitive components, metal elastic components and packaging materials will produce packaging residual stress, especially when applied in high temperature environments, it will show problems such as poor stability; 2) If the sensitive component is based on the metal resistance effect , such as sputtered films or pressure sensors using high-temperature foil metal strain gauges, due to the small resistivity of the metal, the piezoresistive coefficient is very low, and the sensitivity of the sensor is very small (only a few mV / V), so the signal-to-noise ratio is poor. Subsequent signal processing circuits have higher requirements

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