Gas sensing chip and gas sensor

Abstract

The utility model provides a gas sensing chip and a gas sensor, the gas sensing chip comprises a first electrode layer, a first insulating layer, a heating layer, a second insulating layer and a second electrode layer which are arranged along a first direction, the first electrode layer is provided with a first gas sensitive layer, the first gas sensitive layer and the first electrode layer are mutually contacted, and the second electrode layer is provided with a second gas sensitive layer. A first gas sensitive layer is arranged on the first electrode layer, a second gas sensitive layer is arranged on the second electrode layer, the second gas sensitive layer is in contact with the second electrode layer, and the first gas sensitive layer is configured to interact with to-be-detected gas and change the electrical property of the to-be-detected gas. The electric signal generated by the second gas sensitive layer in the closed state can be used as a background signal, and the first gas sensitive layer can be used as a response signal during detection, so that background noise can be filtered, and the problems that the chip is long in response time and is easily influenced by external factors are solved. And the two gas sensitive layers can detect different gases respectively, so that the detection function of the gas sensing chip is expanded.

Description

TECHNICAL FIELD

[0001] The utility model belongs to chip technical field, more specifically, it relates to a kind of gas sensing chip and gas sensor. BACKGROUND

[0002] The semiconductor gas sensor is a kind of semiconductor device widely used in gas detection, which is based on semiconductor technology and uses the specific physical and chemical properties of semiconductor materials to respond to gas, and then detects the presence and concentration change of gas. The traditional semiconductor gas sensor is composed of a set of heating electrodes and a set of sensing electrodes. When detecting gas, the sensor needs to be heated to a stable temperature state for detection, otherwise the temperature will affect the continuous change of resistance, and the starting time of the sensor is long. The sensing material is easily affected by external conditions such as temperature, which can easily lead to misjudgment. Moreover, the types of gas that can be detected by a single sensor are limited, and the range of use is limited. SUMMARY

[0003] The purpose of the embodiment of the utility model is to provide a kind of gas sensing chip and gas sensor, to solve the technical problems of long starting time of sensor, easy to misjudge by external conditions and limited types of gas that can be detected in prior art.

[0004] To achieve the above purpose, the technical scheme adopted by the utility model is to provide a kind of gas sensing chip, including first electrode layer, first insulating layer, heating layer, second insulating layer and second electrode layer arranged along the first direction, the first gas sensitive layer is arranged on the first electrode layer, and the first gas sensitive layer and the first electrode layer are in contact with each other, the second gas sensitive layer is arranged on the second electrode layer, and the second gas sensitive layer and the second electrode layer are in contact with each other, the first gas sensitive layer is configured to interact with the gas to be measured and change its electrical properties.

[0005] In the above scheme, the two sides of the gas sensing chip are provided with gas sensitive layers, and the electrical signal generated by the second gas sensitive layer in the closed state can be used as the background signal. The first gas sensitive layer can be used as the response signal during detection. After removing the background signal from the response signal, the signal after filtering the background noise can be obtained. Whether the gas sensing chip is in a temperature stable state or not, the background noise can be filtered, and the problem of long response time of traditional gas sensing chip and easy to be affected by external factors is solved. Two gas sensitive layers can also detect different gases, which expands the detection function of the gas sensing chip.

[0006] Optionally, the gas sensing chip further comprises a substrate layer, the substrate layer is arranged on a side of the second electrode layer opposite to the second insulating layer, the second electrode layer is arranged on the substrate layer, the substrate layer has a first hollow hole opposite to the second gas sensitive layer, and the second gas sensitive layer is in contact with a space in the first hollow hole.

[0007] In the above scheme, by designing the substrate layer, the gas sensing chip can be processed and formed on the substrate layer, and a gas cavity corresponding to the second gas sensitive layer can be formed on the substrate layer, thereby enriching the functions of the gas sensing chip.

[0008] Optionally, the first gas sensitive layer and the second gas sensitive layer are made of the same material and have the same structure, and the opening of the first hollow hole is shielded.

[0009] In the above scheme, the first gas sensitive layer is in contact with the gas to be measured, and the second gas sensitive layer is arranged in a sealed manner, and the signal generated by the second gas sensitive layer is a background signal. By filtering out the background signal, the signal jitter before reaching the temperature steady state can be filtered out, the problem of long starting time of the traditional gas sensing chip is solved, and the signal-to-noise ratio can be improved and the misjudgment rate can be reduced.

[0010] Optionally, the first gas sensitive layer and the second gas sensitive layer are made of different materials, and the second gas sensitive layer is arranged exposed through the opening of the first hollow hole.

[0011] In the above scheme, the first gas sensitive layer and the second gas sensitive layer are made of different materials and can both be in contact with the gas to be measured, so that the gas sensing chip can detect at least two different gases, and the functions of the gas sensing chip can be enriched.

[0012] Optionally, the first gas sensitive layer partially covers the first electrode layer, the second gas sensitive layer partially covers the second electrode layer, and the electrical contact points of the first electrode layer, the heating layer and the second electrode layer are exposed in a direction opposite to the first direction.

[0013] In the above scheme, the electrical contact points of the first electrode layer, the heating layer and the second electrode layer are exposed in the same direction, which facilitates the electrical connection of the gas sensing chip and the circuit board by wire bonding.

[0014] Optionally, the first gas sensitive layer and the second gas sensitive layer are metal oxide semiconductor material layers.

[0015] Optionally, the first gas sensitive layer and the second gas sensitive layer are zinc oxide or titanium dioxide, which can detect carbon monoxide, hydrogen, oxygen and other gases.

[0016] The utility model also provides a kind of gas sensor, including above-mentioned gas sensing chip, still including the air-permeable layer being arranged along the first direction arrangement, packaging structure and circuit board, the gas sensing chip is arranged on the circuit board and is located in the packaging structure, the packaging structure is arranged on the circuit board, the air-permeable layer is arranged on the opening of the packaging structure and covers the gas sensing chip, the first gas sensitive layer is arranged towards the air-permeable layer, the second gas sensitive layer is arranged towards the circuit board, the gas sensing chip is electrically connected with the circuit board.

[0017] In the above scheme, the two sides of the gas sensing chip are provided with gas sensitive layers, the second gas sensitive layer generates an electrical signal in a closed state, which can be used as a background signal, and the first gas sensitive layer can be used as a response signal during detection. After removing the background signal from the response signal, a signal filtered from the background noise can be obtained. Whether the gas sensing chip is in a temperature stable state or not, the background noise can be filtered, solving the problems of long response time and easy influence by external factors of traditional gas sensing chips. The two gas sensitive layers can also detect different gases, expanding the detection function of the gas sensing chip.

[0018] Optionally, the first gas sensitive layer and the second gas sensitive layer are made of the same material and have the same structure, and the opening of the first hollow hole is shielded by the circuit board.

[0019] In the above scheme, the first gas sensitive layer is in contact with the gas to be detected, and the second gas sensitive layer is sealed. The signal generated by the second gas sensitive layer is a background signal. By filtering out the background signal, the signal jitter before reaching the temperature steady state can be filtered out, solving the problem of long start-up time of the gas sensing chip. In addition, the signal-to-noise ratio can be improved, and the misjudgment rate can be reduced.

[0020] Optionally, the first gas sensitive layer and the second gas sensitive layer are made of different materials, and the circuit board is provided with a second hollow hole in communication with the first hollow hole.

[0021] In the above scheme, the first gas sensitive layer and the second gas sensitive layer are made of different materials and can both be in contact with the gas to be detected, so that the gas sensing chip can detect at least two different gases, and the function of the gas sensing chip can be enriched. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the utility model, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0023] Figure 1 A structure schematic view of a gas sensing chip provided by the embodiment of the present application is provided.

[0024] Figure 2 A structure schematic view of a first gas sensing chip and a circuit board provided by the embodiment of the present application is provided.

[0025] Figure 3 A structure schematic view of a second gas sensing chip and a circuit board provided by the embodiment of the present application is provided.

[0026] Figure 4 A perspective structure view of a gas sensor provided by the embodiment of the present application is provided.

[0027] Figure 5 An exploded structure view of a gas sensor provided by the embodiment of the present application is provided.

[0028] In the figure, each reference sign:

[0029] 100-gas sensing chip; 11-first gas sensitive layer; 12-second gas sensitive layer; 21-first electrode layer; 22-second electrode layer; 31-first insulating layer; 32-second insulating layer; 40-heating layer; 50-substrate layer; 51-first hollow hole;

[0030] 200-circuit board; 201-second hollow hole; 300-encapsulation structure; 400-air permeable layer. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0034] In addition, the terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined as "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise explicitly specified.

[0035] The gas sensing chip provided by the embodiment of the utility model will be described.

[0036] Please refer to Figure 1 , the gas sensing chip 100 includes the first electrode layer 21, the first insulating layer 31, the heating layer 40, the second insulating layer 32 and the second electrode layer 22 arranged along the first direction, the first gas sensitive layer 11 is arranged on the first electrode layer 21, and the second gas sensitive layer 12 is arranged on the second electrode layer 22. In combination with Figure 1 , the first direction can be from top to bottom.

[0037] The first gas sensitive layer 11 is configured to interact with the gas to be measured, and the electrical property of the first gas sensitive layer 11 is changed. The second gas sensitive layer 12 is also configured to interact with the gas to be measured, and the electrical property of the second gas sensitive layer 12 is changed. Specifically, when the first gas sensitive layer 11 and the second gas sensitive layer 12 are in contact with the gas to be measured, the electrical property of the first gas sensitive layer 11 and the second gas sensitive layer 12 will change, and when the concentration of the gas to be measured changes after the first gas sensitive layer 11 and the second gas sensitive layer 12 are in contact with the gas to be measured, the electrical property of the first gas sensitive layer 11 and the second gas sensitive layer 12 will also change. The electrical property can be resistance, capacitance, inductance, etc. For example, when the gas sensitive layer of zinc oxide is exposed to oxygen, the resistance of the gas sensitive layer will change with the increase of the concentration of oxygen. By measuring the change of the electrical property of the gas sensitive layer, whether the gas to be measured exists and the concentration change of the gas to be measured can be indirectly inferred or calculated.

[0038] The first electrode layer 21 is made of conductive material, and the first electrode layer 21 is in contact with the first gas sensitive layer 11. Specifically, the first gas sensitive layer 11 contacts the first electrode layer 21 and the detection circuit, and when the electrical property of the first gas sensitive layer 11 changes, the detection circuit can measure the change of the electrical property of the first gas sensitive layer 11 through the first electrode layer 21.

[0039] The second electrode layer 22 is made of conductive material, and the second electrode layer 22 is in contact with the second gas sensitive layer 12. Specifically, the second gas sensitive layer 12 contacts the second electrode layer 22 and the detection circuit, and when the electrical property of the second gas sensitive layer 12 changes, the detection circuit can measure the change of the electrical property of the second gas sensitive layer 12 through the second electrode layer 22.

[0040] The heating layer 40 can generate heat when powered on, increase the temperature of the gas sensing chip 100, and in particular, can keep the temperature of the first gas sensitive layer 11 and the second gas sensitive layer 12 at a preset stable state, to improve the accuracy of gas detection.

[0041] The first insulating layer 31 is arranged between the first electrode layer 21 and the heating layer 40, and is made of insulating material, which can insulate the first electrode layer 21 and the heating layer 40 from each other, avoiding mutual conduction.

[0042] The second insulating layer 32 is arranged between the second electrode layer 22 and the heating layer 40, and is made of insulating material, which can insulate the second electrode layer 22 and the heating layer 40 from each other, avoiding mutual conduction.

[0043] The first gas sensitive layer 11 can contact the gas to be measured, and the second gas sensitive layer 12 can be closed and not in contact with the gas to be measured, only contacting the background gas. At this time, the materials, sizes, shapes, temperatures and other conditions of the first gas sensitive layer 11 and the second gas sensitive layer 12 are the same, so the signal generated by the first gas sensitive layer 11 can be understood as a response signal, and the signal generated by the second gas sensitive layer 12 can be understood as a background signal. The response signal and the background signal are subtracted to filter out the background noise signal. Whether the temperature of the gas sensitive layer reaches a stable state or not, the signal jump before the temperature reaches a stable state can be filtered out, solving the problem of long start-up time of traditional gas sensing chips, and improving the signal-to-noise ratio and reducing the misjudgment rate. Similarly, the first gas sensitive layer 11 can also be closed, and the second gas sensitive layer 12 can contact the gas to be measured.

[0044] The materials and other conditions of the first gas sensitive layer 11 and the second gas sensitive layer 12 are different, and different gases to be measured can be detected respectively. The signals generated by the first gas sensitive layer 11 and the second gas sensitive layer 12 are both response signals, and different gas sensitive layers can detect different gases.

[0045] The gas sensing chip 100 in the above embodiment comprises a first gas sensitive layer 11, a first electrode layer 21, a first insulating layer 31, a heating layer 40, a second insulating layer 32, a second electrode layer 22 and a second gas sensitive layer 12 arranged in sequence, the gas sensing chip 100 is provided with the gas sensitive layer on both sides, the second gas sensitive layer 12 generates an electrical signal in a closed state, which can be used as a background signal, the first gas sensitive layer 11 can be used as a response signal when detecting gas, and the signal after filtering the background noise can be obtained by removing the background signal, whether the gas sensing chip is in a temperature stable state or not, the background noise can be filtered, and the problems of long response time and being easily affected by external factors of the traditional gas sensing chip are solved. The two gas sensitive layers can also detect different gases respectively, and the detection function of the gas sensing chip 100 is expanded.

[0046] In some embodiments of the utility model, please refer to Figure 1 , the gas sensing chip 100 further comprises a substrate layer 50, the substrate layer 50 is arranged on the side of the second electrode layer 22 away from the second insulating layer 32, the substrate layer 50 has a first hollow hole 51 opposite to the second gas sensitive layer 12, and the second gas sensitive layer 12 is in contact with the space in the first hollow hole 51. The inner wall of the first hollow hole 51 surrounds a gas cavity, which can be in communication with the outside space, that is, the second gas sensitive layer 12 can contact the gas to be detected, or the gas cavity can be arranged in a closed mode and not in communication with the outside space, that is, the second gas sensitive layer 12 cannot contact the gas to be detected. The first hollow hole 51 and the second gas sensitive layer 12 are opposite to each other, that is, the first gas sensitive layer 11 and the first hollow hole 51 are partially or completely opposite.

[0047] By designing the substrate layer 50, the gas sensing chip 100 can be processed and formed on the substrate layer 50, and a gas cavity corresponding to the second gas sensitive layer 12 can be formed on the substrate layer 50, thereby enriching the function of the gas sensing chip 100.

[0048] In some embodiments, the second gas sensitive layer 12 is arranged at the center of the second electrode layer 22, the substrate layer 50 is arranged at the edge of the second electrode layer 22, and the first hollow hole 51 of the substrate layer 50 avoids the second gas sensitive layer 12, so that the substrate layer 50 is directly connected with the second electrode layer 22.

[0049] In some embodiments, the first hollow hole 51 is completely opposite to the second gas sensitive layer 12, and when the second gas sensitive layer 12 is needed to detect gas, the gas to be detected is more easily introduced into the gas cavity and contacted with the second gas sensitive layer 12. The second gas sensitive layer 12 is, for example, circular, and the first hollow hole 51 is also, for example, circular.

[0050] In some embodiments, the substrate layer 50 is any one of a silicon wafer, a glass wafer, a quartz wafer, an alumina ceramic wafer, an aluminum nitride ceramic wafer, a silicon nitride ceramic wafer, a silicon carbide ceramic wafer, a zirconia ceramic wafer, or a polyimide film.

[0051] In some embodiments, the thickness of the substrate layer 50 is 10 to 500 micrometers.

[0052] In some embodiments of the utility model, please refer to Figure 2 , the first gas sensitive layer 11 and the second gas sensitive layer 12 are of the same material and the same structure, for example, the shapes of the two gas sensitive layers are the same, the sizes in each direction are the same, and the opening of the first hollow hole 51 is shielded. Understandably, the first gas sensitive layer 11 and the second gas sensitive layer 12 are completely the same, and the signals generated by the first gas sensitive layer 11 and the second gas sensitive layer 12 at the same temperature when neither of them is in contact with the gas to be measured are the same. The opening of the first hollow hole 51 is sealed, so that when the gas sensing chip 100 is in the gas to be measured, the gas to be measured is only in contact with the first gas sensitive layer 11 and not in contact with the second gas sensitive layer 12, the signal generated by the first gas sensitive layer 11 can be understood as a response signal, and the signal generated by the second gas sensitive layer 12 can be understood as a background signal. Subtracting the response signal from the background signal can filter out the background noise signal, and whether the temperature of the gas sensitive layer reaches a steady state or not, the signal jitter before the temperature reaches a steady state can be filtered out, the problem of long start-up time of the traditional gas sensing chip is solved, the signal-to-noise ratio is improved, and the misjudgment rate is reduced.

[0053] In some embodiments of the utility model, please refer to Figure 3 , the materials of the first gas sensitive layer 11 and the second gas sensitive layer 12 are different, and the second gas sensitive layer 12 is exposed through the opening of the first hollow hole 51, so that the second gas sensitive layer 12 can communicate with the test environment through the opening of the first hollow hole 51, or a gas-permeable film is arranged at the opening of the first hollow hole 51, and only gas can pass through the gas-permeable film to the second gas sensitive layer 12. The first gas sensitive layer 11 and the second gas sensitive layer 12 are not the same, both the first gas sensitive layer 11 and the second gas sensitive layer 12 can be in contact with the gas to be measured, the first gas sensitive layer 11 and the second gas sensitive layer 12 are respectively used for detecting different gases and corresponding gas concentrations, so that the gas sensing chip 100 can detect at least two different gases, and the function of the gas sensing chip 100 can be enriched.

[0054] In some embodiments of the utility model, first gas sensitive layer 11 part covers first electrode layer 21, second gas sensitive layer 12 part covers second electrode layer 22, the electric contact of first electrode layer 21, the electric contact of heating layer 40 and the electric contact of second electrode layer 22 all are exposed to the direction opposite to the first direction, the electric contact of first electrode layer 21, the electric contact of heating layer 40 and the electric contact of second electrode layer 22 all are exposed to the same direction, which is convenient for gas sensing chip 100 to form electric connection with external circuit board by wire bonding. The electric contact is exposed to the opposite direction of the first direction, for example, the first direction is from top to bottom, and each electric contact is arranged upwards.

[0055] In some embodiments of the utility model, please refer to Figure 1 , first gas sensitive layer 11 completely covers or part covers first electrode layer 21. When first gas sensitive layer 11 completely covers first electrode layer 21, the area of first gas sensitive layer 11 is same with the area of first electrode layer 21, and first electrode layer 21 is completely shielded. When first gas sensitive layer 11 part covers first electrode layer 21, the area of first gas sensitive layer 11 is less than the area of first electrode layer 21, and part of first electrode layer 21 is exposed.

[0056] In some embodiments, first gas sensitive layer 11 can be formed by electroplating or the like.

[0057] In some embodiments of the utility model, please refer to Figure 1 , second gas sensitive layer 12 completely covers or part covers second electrode layer 22. When second gas sensitive layer 12 completely covers second electrode layer 22, the area of second gas sensitive layer 12 is same with the area of second electrode layer 22, and second electrode layer 22 is completely shielded. When second gas sensitive layer 12 part covers second electrode layer 22, the area of second gas sensitive layer 12 is less than the area of second electrode layer 22, and part of second electrode layer 22 is exposed, and the exposed second electrode layer 22 can be arranged on substrate layer 50.

[0058] In some embodiments, second gas sensitive layer 12 can be formed by electroplating or the like.

[0059] In some embodiments of the utility model, first gas sensitive layer 11 and second gas sensitive layer 12 are metal oxide semiconductor material layers, for example, N-type metal oxide semiconductor material, P-type metal oxide semiconductor material, PN dual metal oxide semiconductor material. N-type metal oxide semiconductor can be MgO, CaO, TiO2, ZrO2, V2O5, Nb2O5, Ta2O5, M O3, WO3, ZnO, Al2O3, Ga2O3, In2O3, SnO2;P-type metal oxide semiconductor can be Y2O3, La2O3, CeO2, Mn2O3, Co3O4, NiO, PdO, Ag2O, Bi2O3, Sb2O3, TeO2;PN dual metal oxide semiconductor can be H f O2, Cr2O3, Fe2O3, CuO.

[0060] Optionally, first gas sensitive layer 11 and second gas sensitive layer 12 are zinc oxide or titanium dioxide, which can detect carbon monoxide, hydrogen, oxygen and other gases.

[0061] In some embodiments of the utility model, first insulation layer 31 and second insulation layer 32 are made of insulating materials, such as mica, asbestos fiber, phenolic acid ester and the like.

[0062] In some embodiments of the utility model, heating layer 40 is a heating electrode or a heating coil, which can generate heat after being electrified.

[0063] Please refer to Figure 4 And Figure 5 The utility model also provides a kind of gas sensor, and gas sensor includes the gas sensing chip 100 in any embodiment described above, still include the air-permeable layer 400 arranged along the first direction, package structure 300 and circuit board 200, gas sensing chip 100 is arranged on circuit board 200 and is located in package structure 300, package structure 300 is arranged on circuit board 200, air-permeable layer 400 is arranged on the opening of package structure 300 and covers gas sensing chip 100, first gas sensitive layer 11 is arranged towards air-permeable layer 400, second gas sensitive layer 12 is arranged towards circuit board 200, gas sensing chip 100 and circuit board 200 are electrically connected.

[0064] Circuit board 200, package structure 300 and air-permeable layer 400 form package space, and gas sensing chip 100 is arranged in package space, and gas sensing chip 100 is fixed on circuit board 200, and is electrically connected with circuit board 200. Specifically, first electrode layer 21, second electrode layer 22 and heating layer 40 of gas sensing chip 100 are electrically connected with circuit board 200, realize the control to heating layer 40 and receive and calculate the signal of first electrode layer 21 and second electrode layer 22.

[0065] An opening is formed on the packaging structure 300, and the gas-permeable layer 400 is arranged at the opening, so that only gas can pass through the gas-permeable layer 400 and contact the first gas-sensitive layer 11, and other objects cannot pass through the gas-permeable layer 400. The gas-permeable layer 400 can protect the first gas-sensitive layer 11.

[0066] The gas sensor provided by the utility model, adopt above-mentioned gas sensing chip 100, both sides of gas sensing chip 100 are provided with gas-sensitive layer, the electric signal generated by second gas-sensitive layer 12 in closed state can be used as background signal, first gas-sensitive layer 11 can be used as response signal when detecting, after response signal removes background signal, signal after filtering background noise can be obtained, whether gas sensing chip is in temperature stable state or not, background noise can be filtered, solve the problem that traditional gas sensing chip response time is long and is easily influenced by external factors. Two gas-sensitive layers can also detect different gases respectively, and expand the detection function of the gas sensing chip 100.

[0067] In some embodiments of the utility model, please refer to Figure 2 , the materials and structures of the first gas-sensitive layer 11 and the second gas-sensitive layer 12 are same, and the opening of the first hollow hole 51 is shielded by the circuit board 200, that is, the first gas-sensitive layer 11 can contact the gas to be detected, the second gas-sensitive layer 12 cannot contact the gas to be detected and is shielded and sealed by the circuit board 200, at this time, when the gas sensor is located in the gas to be detected, the signal generated by the first gas-sensitive layer 11 can be understood as a response signal, and the signal generated by the second gas-sensitive layer 12 can be understood as a background signal.

[0068] In some embodiments of the utility model, please refer to Figure 3 and Figure 5 , the materials of the first gas-sensitive layer 11 and the second gas-sensitive layer 12 are different, and the circuit board 200 is provided with a second hollow hole 201 in communication with the first hollow hole 51. The inner wall of the first hollow hole 51, the side of the circuit board 200 facing the substrate layer 50 and the side of the substrate layer 50 facing the circuit board 200 form a detection gas cavity, the gas to be detected can enter the detection gas cavity through the second hollow hole 201 and contact the second gas-sensitive layer 12. At the same time, the gas to be detected can contact the first gas-sensitive layer 11 through the gas-permeable layer 400. The first gas-sensitive layer 11 and the second gas-sensitive layer 12 are respectively used for detecting different gases and corresponding gas concentrations.

[0069] In some embodiments of the utility model, the second hollow hole 201 can be a hole with the same shape as the first hollow hole 51 and directly opposite to the first hollow hole 51, and the number thereof is one. Alternatively, the number of the second hollow hole 201 is multiple, and the second hollow hole 201 is directly opposite to the first hollow hole 51.

[0070] In some embodiments of the present application, the air-permeable layer 400 can be an ePTFE (expanded polytetrafluoroethylene) film.

[0071] The above merely provides the preferred embodiments of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gas sensing chip, characterized in that: The device includes a first electrode layer, a first insulating layer, a heating layer, a second insulating layer, and a second electrode layer arranged along a first direction. A first gas-sensitive layer is disposed on the first electrode layer and is in contact with the first electrode layer. A second gas-sensitive layer is disposed on the second electrode layer and is in contact with the second electrode layer. The first gas-sensitive layer is configured to interact with the gas to be measured, thereby changing its electrical properties.

2. The gas sensing chip as described in claim 1, characterized in that: The gas sensing chip further includes a substrate layer disposed on the side of the second electrode layer opposite to the second insulating layer. The substrate layer has a first perforation hole directly opposite the second gas sensing layer, and the second gas sensing layer is in contact with the space inside the first perforation hole.

3. The gas sensing chip as described in claim 2, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are made of the same material and have the same structure, and the opening of the first perforated hole is blocked.

4. The gas sensing chip as described in claim 2, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are made of different materials, and the second gas-sensitive layer is exposed through the opening of the first perforated hole.

5. The gas sensing chip according to any one of claims 1-4, characterized in that: The first gas-sensitive layer partially covers the first electrode layer, and the second gas-sensitive layer partially covers the second electrode layer. The electrical contacts of the first electrode layer, the electrical contacts of the heating layer, and the electrical contacts of the second electrode layer are all exposed in a direction opposite to the first direction.

6. The gas sensing chip according to any one of claims 1-4, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are metal oxide semiconductor material layers.

7. The gas sensing chip as described in claim 6, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are zinc oxide or titanium dioxide.

8. A gas sensor, characterized in that: The gas sensing chip according to any one of claims 1-7 further includes a breathable layer, a packaging structure, and a circuit board arranged along the first direction. The gas sensing chip is disposed on the circuit board and located within the packaging structure. The packaging structure is disposed on the circuit board. The breathable layer is disposed on the opening of the packaging structure and covers the gas sensing chip. The first gas-sensitive layer is disposed facing the breathable layer, and the second gas-sensitive layer is disposed facing the circuit board. The gas sensing chip is electrically connected to the circuit board.

9. The gas sensor as described in claim 8, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are made of the same material and have the same structure, and the opening of the first perforated hole is blocked by the circuit board.

10. The gas sensor as described in claim 8, characterized in that: The first gas-sensitive layer and the second gas-sensitive layer are made of different materials, and the circuit board has a second hollow hole that communicates with the first hollow hole.

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