MEMS gas sensor and manufacturing method thereof

Abstract

The invention relates to the technical field of gas detection, and in particular relates to an MEMS gas sensor. The MEMS gas sensor comprises a monocrystalline silicon substrate, a porous silicon layer which is formed on the upper surface of the monocrystalline silicon substrate and has thickness downwards, a heat insulation trough formed on the lower surface of the monocrystalline silicon substrate in an inverse manner, a lower insulation layer, a heating layer, an upper insulation layer and a gas sensitive layer, wherein the bottom surface of the heat insulation trough is positioned just under the porous silicon layer; the heat insulation trough comprises one or multiple trench groups; the lower insulation layer covers the porous silicon layer and the upper surface of the monocrystalline silicon substrate and comprises a first silicon dioxide layer, a second silicon dioxide layer and a silicon nitride layer from bottom to top in sequence; the heating layer, the upper insulation layer and the gas sensitive layer are arranged above the lower insulation layer. The invention also correspondingly discloses a manufacturing method of the MEMS gas sensor. By virtue of the structures of porous silicon and the heat insulation trough, the heat insulation effect is enhanced; the lower insulation layer effectively prevents the heat insulation layer warping to break away from the heating layer at high temperature; meanwhile, under the supporting of the porous silicon layer, deformation and cracks, which are caused by non-uniform stress, of the lower insulation layer are prevented, and thus the service life of the gas sensor is prolonged.

Description

technical field [0001] The invention relates to the technical field of gas detection, in particular to a MEMS gas sensor and a manufacturing method thereof. Background technique [0002] The various environments of human production, living and living are filled with various gases. The detection of gases, especially the detection of toxic, harmful, flammable and explosive gases, is an important means to ensure people's safe production, healthy living and comfortable life. At present, there are traditional large-scale detection equipment for gas detection, such as gas detection instruments based on mass spectrometry, energy spectroscopy and chromatography, but these instruments are bulky and expensive, which limits their popularization and development. Therefore, some small gas sensors have been developed in recent years. Gas sensors are widely used in petroleum, petrochemical, gas, metallurgy, electric power, automobile industry, environmental sanitation, meteorological detec...

AI Technical Summary

Problems solved by technology

[0006] (1) The stability is poor, and the device is deformed and cracked due to uneven force, resulting in device failure;

[0007] (2) The heat insulation effect is poor, and the air gap between the heat insulation tanks is large, resulting in faster heat loss, which affects the heat insulation effect

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