Capacitive silicon carbide high-temperature pressure sensor and preparation method thereof

Abstract

The invention relates to a capacitive silicon carbide high-temperature pressure sensor and a preparation method thereof, the sensor comprises a plurality of capacitive silicon carbide high-temperaturepressure sensing units arranged in an array, each capacitive silicon carbide high-temperature pressure sensing unit comprises a substrate, two sides of the substrate are connected with support columns, and the middle part of the substrate is connected with a plurality of lower electrodes arranged in an array. The lower electrode is matched with a plurality of arrayed upper electrodes connected tothe silicon carbide film to form a plurality of sub-capacitors, the two sides of the silicon carbide film are connected to the tops of the supporting columns, the tops of the upper electrodes are connected with upper electrode leads, and a glass cover plate is arranged above the upper electrode leads; cavities are formed among the adjacent supporting columns, the silicon carbide film and the substrate; the upper electrode and the lower electrode are vertically arranged, and the pressure change is reflected by changing the area between the upper electrode and the lower electrode; according tothe preparation method, etching, sputtering, corrosion, bonding and other processes are adopted, the output signal is increased, the signal-to-noise ratio is increased, the linearity is improved, andthe working temperature of the pressure sensor is increased.

Description

technical field [0001] The invention belongs to the technical field of pressure sensors, and in particular relates to a capacitive silicon carbide high-temperature pressure sensor and a preparation method thereof. Background technique [0002] The pressure sensor is a device or device that can sense the pressure signal and convert the pressure signal into an available electrical signal output according to certain rules. It is widely used in airborne air data test systems, aviation air data calibrators, cabin pressure tests, Fields such as aerospace ground test systems and high-performance wind tunnels. At the same time, in modern advanced fighters, it is often used to realize liquid high pressure control of wing surface and landing gear, hydraulic control of automatic system, air pressure test of cooling gas of avionics equipment, blowing pressure measurement of deicing system, oil and gas inlet of backup power engine Terminal pressure test, cockpit pressure measurement and...

AI Technical Summary

Problems solved by technology

The preparation of a single capacitive pressure sensor is relatively simple, but its pressure detection range is limited. When the pressure changes, because it changes the distance between the upper and lower electrodes, it can be seen from the parallel plate capacitance formula that its nonlinearity is relatively large. Obviously, it is difficult to apply to large-scale pressure detection

The pressure diaphragm electrode of the differential capacitive pressure sensor is located between two fixed electrodes, forming two capacitors; under the action of pressure, the capacity of one capacitor increases and the capacity of the other decreases accordingly, and the measurement result is determined by the differential pressure sensor. The circuit output has the advantages of high measurement sensitivity and good linearity, but because the symmetry is difficult to guarantee, it is difficult to process

At the same time, both pressure sensors use silicon as their thin-film structure, so it is difficult to use under high temperature conditions

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