CN-116930267-B - Sapphire-based gas sensor based on micro-electromechanical system and manufacturing method thereof

CN116930267BCN 116930267 BCN116930267 BCN 116930267BCN-116930267-B

Abstract

The invention relates to a sapphire-based gas sensor based on a micro-electromechanical system and a manufacturing method thereof, wherein the gas sensor comprises a substrate, a supporting layer, a heating component, a dielectric layer, a detection electrode and a sensing layer, wherein the substrate is provided with a heat insulation cavity, the supporting layer is arranged on the substrate and is provided with a heat collecting area suspended above the heat insulation cavity, the heating component is arranged on the supporting layer and is provided with a heating wire, the dielectric layer is arranged on the heating component and is provided with a heat collecting area suspended above the heat insulation cavity, the detection electrode is arranged on the dielectric layer, the sensing layer is arranged on the detection electrode, and a gas-sensitive material is deposited on the detection electrode, at least one heat collecting area of the supporting layer and the dielectric layer is provided with a plurality of through holes penetrating along the stacking direction, and the pore diameters of the through holes in the supporting layer and the dielectric layer are arranged in a mode of gradually changing from the heat collecting area to the peripheral side.

Inventors

LIANG JIANHAN
ZHOU QINGFENG
Wan Zhuan

Assignees

艾感科技(广东)有限公司

Dates

Publication Date: 20260508
Application Date: 20230703
Priority Date: 20230223

Claims (10)

1. A sapphire-based gas sensor based on microelectromechanical systems, comprising: A substrate (10) having an insulating cavity; A support layer (20) disposed on the substrate (10) and having a heat accumulating region suspended above the insulating cavity; A heating element (30) disposed on the support layer (20) and comprising a heating wire (302); a dielectric layer (40) disposed on the heating assembly (30) and having a heat accumulating region suspended above the insulating cavity; a detection electrode (50) disposed on the dielectric layer (40); a sensing layer (60) disposed on the detection electrode (50) and deposited with a gas sensitive material (70); Wherein, the The heat collecting region of at least one of the support layer (20) and the dielectric layer (40) has a plurality of through holes formed in the stacking direction, and the through hole apertures in the respective layers of the support layer (20) and the dielectric layer (40) are arranged in such a manner that the extending direction from the heat collecting region to the peripheral side gradually changes.
2. A gas sensor according to claim 1, wherein the heat accumulating region of the support layer (20) and/or the dielectric layer (40) is constituted by a plurality of suspension beams and a carrier layer, and wherein respective one ends of the plurality of suspension beams are connected to the carrier layer and respective other ends of the plurality of suspension beams are connected to the support layer (20) and/or the dielectric layer (40), wherein, The through holes distributed in the heat collecting region are configured in a manner of gradually decreasing along the extending direction of the cantilever beam from the bearing layer.
3. The gas sensor according to claim 2, wherein in a state where the through holes laid out in the heat collecting region are arranged in such a manner as to gradually decrease in a direction in which the cantilever beam extends from the carrier layer, the cantilever beam is arranged in such a manner that a width thereof gradually increases toward an end where the carrier layer is located.
4. A gas sensor according to claim 2 or 3, wherein the heating element (30) further comprises a heating electrode (301), and the heating electrode (301) is electrically connected to both ends of the heating wire (302), wherein, The heating wire (302) is arranged in a manner that it overlaps the carrier layer of the support layer (20) and/or the dielectric layer (40) as seen in the stacking direction.
5. A gas sensor according to claim 1, characterized in that the respective heat accumulating areas of the support layer (20) and the dielectric layer (40) are arranged in such a way that they coincide or are contained with each other as seen in the stacking direction.
6. A gas sensor according to claim 2, wherein the detection electrode (50) comprises an interdigital electrode (501), the respective electrical interdigital fingers (502) of a pair of the interdigital electrodes (501) meet each other to form a sensing region (503) for detection, and the sensing region (503) is arranged in such a manner as to overlap with the supporting layer (20) and/or the carrier layer of the dielectric layer (40) as viewed in the stacking direction.
7. The gas sensor according to claim 1, wherein the sensing layer (60) deposited with the gas sensitive material (70) comprises a first functional area and a second functional area, wherein, The first functional region is configured in such a way that it overlaps/is contained with the heat accumulating region of the support layer (20) and/or the dielectric layer (40) as seen in the stacking direction; the second functional region is connected to the first functional region in a manner that it does not overlap or contain the heat accumulating region of the support layer (20) and/or the dielectric layer (40) as seen in the stacking direction.
8. A gas sensor according to claim 4, characterized in that the dielectric layer (40) is configured with a receiving area adapted in shape to a heating electrode (301) of the heating assembly (30).
9. The gas sensor according to claim 1, wherein the support layer (20) and/or the dielectric layer (40) is a composite structure formed of at least one of silicon nitride and silicon oxide.
10. A method of manufacturing a mems-based sapphire-based gas sensor comprising: -configuring a substrate (10); Depositing a support layer (20) to the substrate (10); Depositing a heating element (30) comprising a heating wire (302) onto the support layer (20); Depositing a dielectric layer (40) to the heating assembly (30); depositing a detection electrode (50) to the dielectric layer (40); depositing a sensing layer (60) comprising a gas sensitive material (70) to the detection electrode (50); Etching the structure formed by the stack of layer structures to form the support layer (20) and the dielectric layer (40) into a heat accumulating region comprising a cantilever structure; Wherein, the The heat collecting region of at least one of the support layer (20) and the dielectric layer (40) has a plurality of through holes penetrating in the stacking direction, and the hole diameters of the through holes in the respective layers of the support layer (20) and the dielectric layer (40) are arranged in such a manner as to gradually change from the heat collecting region to the peripheral side extending direction.

Description

Sapphire-based gas sensor based on micro-electromechanical system and manufacturing method thereof Technical Field The invention relates to the technical field of gas sensors, in particular to a sapphire-based gas sensor based on a micro-electromechanical system and a manufacturing method thereof. Background A metal oxide semiconductor gas sensor is a sensor for sensing a gas from an object in a manner that measures a change in conductivity that occurs when a metal oxide semiconductor reacts with the gas. The metal oxide semiconductor gas sensor has the advantages of low manufacturing cost, small volume, high temperature stability, high sensitivity, high response speed and the like, and is widely used. Particularly in the case of using a metal oxide semiconductor having a nano structure, the reaction between the metal oxide semiconductor and the gas can be maximized due to the inherent characteristic that the specific surface area of the nano structure is large, and the above-described advantages of the metal oxide semiconductor gas sensor can be further enhanced due to the characteristic pores that the gas can rapidly diffuse into the metal oxide semiconductor having a larger nano structure. CN108318548a discloses a single cantilever beam gas sensor, which comprises a silicon substrate, a supporting film, a heating resistor, an isolating film and a detecting electrode which are sequentially laminated, wherein the gas sensor is in a 'T' -shape and has a base structure and a cantilever structure, and a gas sensitive material is arranged on the end part of the cantilever structure. The invention also provides a sensor array composed of the single cantilever beam gas sensor, and a preparation method of the gas sensor, which comprises the steps of (1) selecting a silicon substrate, (2) preparing a support film, (3) preparing a heating resistor, (4) preparing an isolating film, (5) preparing a detection electrode, (6) releasing a film, and (7) loading a gas sensitive material. CN102359981a discloses a resistive gas sensor with a six-layer structure of two support cantilever beams and a manufacturing method, and the structure of the sensor comprises a substrate frame, a heat insulation cavity, a heating film area, a transition area, a support cantilever beam, a heating resistance wire, a power supply lead, a power supply electrode, an isolation layer, an interdigital electrode, a detection lead, a detection electrode and a sensitive film. The heat insulation device is structurally characterized in that a heating film area above a heat insulation cavity is connected with a substrate frame through a transition area and a supporting cantilever beam, heating resistance wires are arranged on the heating film area in a fold line mode and connected with power supply electrodes on the substrate frame through power supply leads, an isolation layer covers the heating film area and the supporting cantilever beam and tightly wraps the heating resistance wires and the power supply leads, interdigital electrodes are arranged on the isolation layer and connected with detection electrodes through detection leads, and a sensitive film is located at the isolation layer on the heating film area and covers the whole interdigital electrodes and is well electrically connected with the whole interdigital electrodes. While conventional semiconductor resistive gas sensors can directly prepare gas-sensitive materials on micro-thermal platforms by using semiconductor processes such as sputtering and evaporation, the compact surface structure of the semiconductor resistive gas sensors greatly reduces the response and sensitivity of the gas-sensitive materials, and the substrate based on ceramic plates also greatly increases the power consumption of devices, in general, in order to maintain the low power consumption of the sensor, the substrate of the conventional MEMS semiconductor gas sensor is usually provided with a heat-insulating cavity formed by hollowed etching, and the hollowed-out opening will cause a certain degree of decline of mechanical strength, when the sensor device is subjected to unexpected sudden impact or vibration, the decline of mechanical strength can cause the mechanical stability and the working state of the sensor device to be influenced indefinitely, so that the prior art generally chooses to enhance the width of the cantilever beams, or reduces or even eliminates the cantilever beams to ensure the mechanical stability, but causes the multiple increase of heat, and in order to reduce the power consumption of the device, the cantilever beams are increased in number, or the cantilever beams width are reduced, and the measure faces a certain sacrifice of mechanical strength. Accordingly, there remains a need in the art for at least one or more of the technical problems. Furthermore, since the applicant has studied numerous documents and patents on the one hand, and since the applicant has made the present invention,