Indirectly-heated silicon-based film catalytic hydrogen sensor and processing method thereof

Abstract

The invention provides an indirectly-heated silicon-based film catalytic hydrogen sensor, which is obtained by an MEMS processing technology and comprises a silicon substrate. The upper surface of thesilicon substrate is provided with a heat insulation layer, and the lower surface of the silicon substrate is provided with one or a pair of heat insulation grooves extending to the heat insulation layer. A pair of heating coils made of high-resistance temperature coefficient materials is arranged on the surface of the heat insulation layer, catalytic film layers are arranged on the inner sides,the outer sides or the upper portions of the heating coils, a high-temperature-resistant medium layer covers one surface of each catalytic film layer, a gap is reserved in the other surface of each catalytic film layer, and precious metal film resistors are arranged on the outer ring of the heat insulation layer. The hydrogen sensor provided by the invention can work in a catalytic combustion modeand a thermal conductivity mode at the same time, and is small in size, low in power consumption, quick in response and long in service life.

Description

technical field [0001] The invention belongs to the technical field of hydrogen sensors, and in particular relates to a side-heating silicon-based thin-film catalytic hydrogen sensor and a processing method thereof. Background technique [0002] The catalytic combustion gas sensor uses the thermal effect principle of catalytic combustion. The detection element and the compensation element are paired to form a measuring bridge. If it rises, the resistance of the platinum wire inside it will also increase accordingly, so that the balance bridge will be out of balance, and an electrical signal proportional to the concentration of combustible gas will be output. [0003] In order to improve the catalytic efficiency, the catalyst is usually made of a noble metal catalyst supported by porous alumina ceramics, usually olive-shaped or spherical, so it is called a bead element. The catalyst consists of very fine platinum filaments, usually only 25-50 microns. The diameter of the ca...

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Problems solved by technology

The diameter of the catalyst is about 0.5-1mm, and the platinum wire is easily broken under strong vibration; the noble metal catalyst supported by porous ceramics has a high response to all combustible gases, so it can only be used as a combustible gas sensor. Non-single hydrogen sensor

[0004] At the same time, the porous ceramics of the catalyst are very easy to absorb fine particles in the air, resulting in a significant decrease in the specific surface area of ​​the porous ceramics, and the catalytic activity is also greatly reduced. This means that the sensor needs to be calibrated regularly to correct errors, and the service life is also greatly improved. reduce

[0005] Our company's Chinese patent document "A Hydrogen Sensor and Its Processing Method" with the application number 201810220141.2 discloses a miniature hydrogen sensor that can measure any hydrogen concentration, making up for the shortcomings of the existing technology; making the hydrogen sensor selectivity, Issues such as security, stability, sensitivity, and weak output signals have been resolved to varying degrees

However, the stability and service life of the device still need to be further improved

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