High-temperature and large-range silicon-sapphire pressure sensor structure

Abstract

The invention provides a high-temperature and large-range silicon-sapphire pressure sensor structure, which comprises a titanium alloy shell, two titanium alloy diaphragms, a connecting cylinder, a sapphire diaphragm, a monocrystalline silicon strain resistor and a metal wire. One titanium alloy diaphragm is combined with the sapphire diaphragm through vacuum sintering so as to form a sensitive element of a pressure sensor. A layer of monocrystalline silicon thin film with the thickness thereof to be 0.1-0.5 mum grows on the sapphire diaphragm in the heteroepitaxial manner. On an epitaxial film, the monocrystalline silicon strain resistor is prepared through the semiconductor plane process. The resistor forms a wheatstone bridge. The lower part of the other titanium alloy diaphragm is connected to a cylinder and the lower surface of the cylinder is provided with a spherical concave surface. The spherical concave surface completely fit the sapphire diaphragm during the deforming process. Meanwhile, the spherical concave surface is kept at a spacing of 5-10 mum from the sapphire diaphragm when there is no load. According to the technical scheme of the invention, upper and lower diaphragms form a separation type double-diaphragm structure. During the measurement process of a small-range pressure, the advantage of high sensitivity is realized. Meanwhile, the structure can be used for the measurement of large-range pressures.

Description

technical field [0001] The invention belongs to the technical field of sensor optimization design in advanced sensor technology research, and specifically relates to a high-temperature and large-range silicon-sapphire pressure sensor structure. Background technique [0002] The high-precision measurement technology of pressure under high temperature and high pressure environment has a very broad application prospect in the fields of industry, aviation, aerospace, weaponry and other fields. At the same time, due to the limitation of the temperature characteristics of sensitive materials, this technology has always been a difficult problem to be overcome in the field of pressure measurement. [0003] At present, high-temperature pressure sensors developed at home and abroad include alloy film pressure sensors, silicon-on-insulator (SOI) pressure sensors, SiC pressure sensors, silicon-sapphire pressure sensors, etc. Among them, the alloy thin-film pressure sensor uses thin-fil...

AI Technical Summary

Problems solved by technology

Among them, the alloy thin-film pressure sensor uses thin-film deposition to replace the bonding of traditional adhesive strain gauges, and realizes pressure measurement at high temperatures. Many inconveniences; SOI pressure sensors are limited by the process and structure, and the application range is limited; SiC pressure sensors are very difficult to prepare single crystal and thin film materials and device manufacturing, and there is still a big gap between the research level and the actual application requirements ; Silicon-sapphire pressure sensor has become a hot research technology due to its good mechanical properties and high temperature resistance

[0004] The structure of the piezoresistive pressure sensor is mainly divided into two types: single diaphragm and double diaphragm. The single diaphragm structure is used for small-range pressure measurement with high sensitivity, but the measurement range is small; the double-diaphragm structure is used for large-range pressure measurement. pressure measurement, the measurement range is large, but the sensitivity is low

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