CN112268938B - NOx gas sensor - Google Patents
NOx gas sensor Download PDFInfo
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- CN112268938B CN112268938B CN202011132592.4A CN202011132592A CN112268938B CN 112268938 B CN112268938 B CN 112268938B CN 202011132592 A CN202011132592 A CN 202011132592A CN 112268938 B CN112268938 B CN 112268938B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The invention discloses a NOx gas sensor, which belongs to the field of gas sensors; wherein the method sequentially comprises the following steps from bottom to top: the device comprises a silicon substrate layer, a supporting layer, a heating electrode, an insulating layer and a test electrode layer; wherein a heat insulation cavity is arranged on one side of the testing end above the silicon substrate layer; the supporting layer completely covers the silicon substrate layer; the heating electrode is arranged between the supporting layer and the insulating layer, and the insulating layer is used for isolating the heating electrode from the test electrode layer; the test electrode layer includes: and the second electrode, the first electrode and the third electrode are arranged in parallel, wherein each of the first electrode, the second electrode and the third electrode extends from the electrode end to the testing end. In the invention, the first electrode is made of a material sensitive to NOx, and the second electrode and the third electrode are made of noble metal and form a three-electrode system. During testing, the third electrode is used as a reference electrode, and the polarization voltage of the second electrode can be regulated and controlled; after passing through the NOx gas, the NOx content can be determined by recording the current change between the first electrode and the second electrode.
Description
Technical Field
The invention belongs to the technical field of gas sensors, and particularly relates to a NOx gas sensor.
Background
Currently widely used NOx gas sensors include both semiconductor type and solid electrolyte type. The semiconductor type NOx gas sensor is poor in accuracy, and is difficult to meet increasingly severe use environments; solid electrolyte NOx gas sensor, it is necessary to completely decompose NOx into O 2 The sensor has complex structure, more electrodes and low operation cost. Therefore, adjusting the sensor structure and changing the sensor operation mode is a major technical difficulty of NOx gas sensors.
In consideration of the advantages of the electrochemical gas sensor in terms of detection precision, relevant structural design is developed, and the method has a certain significance in realizing quantitative analysis of sensor detection. In addition, along with research and development of MEMS technology, the operability of manufacturing planar structure devices is increased, so that the preparation of the sensor taking silicon base as a substrate has certain advantages in the aspects of cost reduction, integration increase and the like.
Aiming at the problem, we provide a gas sensor which is made of a material sensitive to NOx, has simple structure and is easy to operate.
Disclosure of Invention
Aiming at the problems in the background art, the invention provides a NOx gas sensor, which is characterized by comprising the following components in sequence from bottom to top: the device comprises a silicon substrate layer, a supporting layer, a heating electrode, an insulating layer and a test electrode layer; wherein a heat insulation cavity is arranged on one side of the testing end above the silicon substrate layer; the supporting layer completely covers the silicon substrate layer; the heating electrode is arranged between the supporting layer and the insulating layer, and the insulating layer is used for isolating the heating electrode from the test electrode layer;
the test electrode layer includes: and the second electrode, the first electrode and the third electrode are arranged in parallel, wherein each of the first electrode, the second electrode and the third electrode extends from the electrode end to the testing end.
The heat insulation cavity is a groove with a V-shaped or arc-shaped section.
The supporting layer consists of a supporting layer insulating region, a middle part and a supporting layer supporting region, and the supporting layer insulating region at the testing end is positioned right above the heat insulation cavity.
The heating electrode includes: the heating electrode heating zone, the power supply lead and the power supply electrode are arranged at the test end, the heating electrode heating zone is in a zigzag shape, and the heating electrode heating zone is positioned right above the support layer insulating zone of the support layer.
The supporting layer is SiO 2 /Si 3 N 4 And (3) a composite membrane.
The insulating region of the supporting layer is rectangular.
The heating electrode is Pt.
The insulating layer is SiO 2 /Si 3 N 4 And (3) a composite membrane.
The lengths of the first electrode, the second electrode and the third electrode are the same; the first electrode is equidistant from the second electrode and from the third electrode.
The material composition of the first electrode is WO 3 60-80% and 20-40% of Pt; first, theThe two and third electrode components were Pt.
The invention has the beneficial effects that:
1. compared with the traditional sheet type sensor, the gas sensor has the advantages of small volume, low power consumption, low cost and easy integration based on the MEMS technology.
2. The invention adopts the cavity prepared by the corrosion of the front body silicon, can reduce the heat consumption of the sensor, increases the heat utilization of the sensor, and has stable and easily controlled processing technology.
3. In the invention, the first electrode is made of a material sensitive to NOx, and the second electrode and the third electrode are made of noble metal and form a three-electrode system. In the test process, the third electrode is used as a reference electrode, and the polarization voltage of the second electrode can be regulated and controlled. After the NOx gas is introduced, the NOx content can be determined by recording the current change between the first electrode and the second electrode, so that the purpose of NOx detection is realized. The invention has simple structure and easy operation.
Drawings
FIG. 1 is a schematic diagram of an embodiment of a NOx gas sensor according to the present invention;
FIG. 2 is a top view of a support layer according to an embodiment of the invention;
FIG. 3 is a top view of a heater electrode and a support layer according to an embodiment of the present invention;
FIG. 4 is a top view of an insulating layer according to an embodiment of the present invention;
fig. 5 is a top view of an insulating layer and a test electrode layer in an embodiment of the invention.
Wherein:
the device comprises a 1-silicon substrate layer, a 2-supporting layer, a 3-heating electrode, a 4-insulating layer, a 5-test electrode layer, a 11-substrate layer cavity, a 21-supporting layer insulating region, a 22-supporting layer supporting region, a 31-heating electrode heating region, a 32-power supply lead, a 33-power supply electrode, a 41-insulating layer through hole, a 51-first electrode, a 52-second electrode and a 53-third electrode.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
In the embodiment of the present invention shown in fig. 1 to 5, the structure sequentially includes, from bottom to top: the device comprises a silicon substrate layer 1, a supporting layer 2, a heating electrode 3, an insulating layer 4 and a test electrode layer 5; wherein the silicon substrate 1 is a rectangular body, and a heat insulation cavity 11 is arranged on one side of a test end above the silicon substrate 1; the support layer 2 completely covers the silicon substrate layer 1; the heating electrode 3 is arranged between the supporting layer 2 and the insulating layer 4, and the insulating layer 4 is used for isolating the heating electrode 3 and the test electrode layer 5;
the test electrode layer 5 disposed above the insulating layer 4 includes: a second electrode 52, a first electrode 51, and a third electrode 53 arranged in parallel, wherein each of the first electrode 51, the second electrode 52, and the third electrode 53 extends from an electrode end to a test end; and the lengths of the first electrode 51, the second electrode 52 and the third electrode 53 are substantially the same, and the pitches of the first electrode 51 and the second electrode 52 and the pitches of the third electrode 53 are substantially the same.
In this embodiment, the supporting layer 2 is composed of a supporting layer insulation region 21, a middle portion and a supporting layer support region 22, the supporting layer insulation region 21 at the test end is located right above the heat insulation cavity 11, and the supporting layer insulation region 21 is rectangular in top view;
in the present embodiment, the supporting layer is SiO 2 /Si 3 N 4 A composite membrane;
in this embodiment, the test electrode layer 5 is deposited on the insulating layer 4;
in this embodiment, the material composition of the first electrode 51 is WO3 60-80%, pt 20-40%, the composition of the second electrode 52 and the third electrode 53 are both Pt 100%,
in the present embodiment, the widths of the non-electrode terminal portions (the test terminal and the middle portion) of the first electrode 51, the second electrode 52, and the third electrode 53 are smaller than the widths of the electrode terminals.
In the present embodiment, the insulating layer is SiO 2 /Si 3 N 4 A composite membrane;
the heat insulation cavity 11 shown in fig. 1 is a groove with a V-shaped or arc-shaped cross section; in this embodiment, the insulating chamber 11 is realized by a frontal bulk silicon etching preparation.
The heating electrode 3 as shown in fig. 3 includes: the heating electrode heating zone 31, the power supply lead 32 and the power supply electrode 33 are arranged at the test end, and the heating electrode heating zone 31 arranged at the test end is in a zigzag shape and is positioned right above the supporting layer insulating zone 21; the heating electrode heating zone 31 is connected with an external power supply through a power supply lead 32 and a power supply electrode 33, and after being heated by the heating electrode 3, the temperature of the testing zone can reach 200-700 ℃; the heating electrode 3 is distributed above the supporting layer 2, and the supporting layer 2 plays an insulating role besides a supporting role and is used for isolating the silicon substrate layer 1 and the heating electrode 3, and meanwhile, the stability and the utilization of the heat of a cavity below are further ensured;
in the present embodiment, the heating electrode 3 has a composition of Pt.
As shown in fig. 4 and 5, the insulating layer 4 has two through holes 41 at the electrode end of the insulating layer 4, which are matched with the shape and position of the power supply electrode 33, for leading out the power supply electrode 33 of the heating layer; the insulating layer 4 serves to isolate the lower heater electrode 3 from the upper test electrode layer 5 at the test end.
The testing process and principle of the invention:
and step 1, heating the test area to 200-500 ℃ by heating the electrode 2, so that the temperature of the test area where the first electrode 51, the second electrode 52 and the third electrode 53 are positioned is increased.
Step 2, electrifying the first electrode 51 in the middle, generating 5-15V voltage between the first electrode 51 and the second electrode 52 test loop and between the first electrode 51 and the second electrode 52 and between the first electrode 53 test loop and the third electrode 53 test loop, and recording current changes of the first electrode 51 and the third electrode 53 test loop and the second electrode 52 and the third electrode 53 test loop; wherein the first electrode 51 and the second electrode 52 test loops are used to measure the changes in electrode potential due to the changes in the detected gas for counteracting errors in electrode polarization.
And step 3, introducing NOx into the surrounding environment, wherein the NOx reacts with the first electrode sensitive material to a certain extent, active state gas molecules are adsorbed on the surface of the electrode, the resistance of the electrode is changed, the current of a working loop is changed, and a required gas signal can be screened out through a circuit control system, so that an electrical signal corresponding to a certain NOx concentration is determined.
If different NOx is required to be calibrated quantitatively, only the concentration of the gas to be measured is required to be changed, and the relation between the concentration of the NOx and the electric signal is determined according to the change of the current value of the working circuit.
Claims (8)
1. A NOx gas sensor comprising, in order from bottom to top: the device comprises a silicon substrate layer (1), a supporting layer (2), a heating electrode (3), an insulating layer (4) and a test electrode layer (5); wherein a heat insulation cavity (11) is arranged at one side of the testing end above the silicon substrate layer (1); the supporting layer (2) completely covers the silicon substrate layer (1); the heating electrode (3) is arranged between the supporting layer (2) and the insulating layer (4), and the insulating layer (4) is used for isolating the heating electrode (3) and the test electrode layer (5); the supporting layer (2) is SiO 2 /Si 3 N 4 A composite membrane;
the test electrode layer (5) comprises: a second electrode (52), a first electrode (51) and a third electrode (53) arranged in parallel, wherein each of the first electrode (51), the second electrode (52) and the third electrode (53) extends from an electrode end to a test end; -the first electrode (51) is equidistant from the second electrode (52) and from a third electrode (53); the material composition of the first electrode (51) is WO 3 60-80% and 20-40% of Pt; the second electrode (52) and the third electrode (53) are Pt;
the heating electrode (3) heats the test area to 200-500 ℃; the first electrode (51) and second electrode (52) test loops are used to measure changes in electrode potential due to changes in the detected gas to cancel errors in electrode polarization.
2. A NOx gas sensor according to claim 1, characterized in that the insulating chamber (11) is a groove having a V-shaped or arc-shaped cross section.
3. A NOx gas sensor according to claim 1, characterized in that the support layer (2) consists of a support layer insulation zone (21), a middle part and a support layer support zone (22), the support layer insulation zone (21) at the test end being located directly above the insulating chamber (11).
4. A NOx gas sensor according to claim 3, characterized in that the support layer insulation region (21) is rectangular.
5. A NOx gas sensor according to claim 3, characterized in that the heating electrode (3) comprises: the heating electrode heating zone (31), the power supply lead (32) and the power supply electrode (33) are arranged at the test end, the heating electrode heating zone (31) is in a zigzag shape, and the heating electrode heating zone is positioned right above the supporting layer insulating zone (21) of the supporting layer (2).
6. A NOx gas sensor according to one of claims 1 or 5, characterized in that the heating electrode (3) is of Pt composition.
7. A NOx gas sensor according to claim 1, characterized in that the insulating layer (4) is SiO 2 /Si 3 N 4 And (3) a composite membrane.
8. A NOx gas sensor according to claim 1, characterized in that the first electrode (51), the second electrode (52) and the third electrode (53) are of the same length.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011132592.4A CN112268938B (en) | 2020-10-21 | 2020-10-21 | NOx gas sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011132592.4A CN112268938B (en) | 2020-10-21 | 2020-10-21 | NOx gas sensor |
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| CN112268938A CN112268938A (en) | 2021-01-26 |
| CN112268938B true CN112268938B (en) | 2023-08-15 |
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| CN202011132592.4A Active CN112268938B (en) | 2020-10-21 | 2020-10-21 | NOx gas sensor |
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Citations (6)
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| CN101889201A (en) * | 2007-10-09 | 2010-11-17 | 佛罗里达大学研究基金公司 | Multifunctional potentiometric gas sensor array with an integrated temperature control and temperature sensors |
| CN103645242A (en) * | 2013-12-04 | 2014-03-19 | 上海交通大学 | Ionizing sensor based on discharge electric field with micro-gap polarization structure |
| CN107407652A (en) * | 2015-03-11 | 2017-11-28 | 罗伯特·博世有限公司 | Manufacture method and corresponding gas sensor for gas sensor |
| CN109709194A (en) * | 2019-03-13 | 2019-05-03 | 常州君堃电子有限公司 | Nitrogen oxides ammonia integral sensor |
| CN109709193A (en) * | 2019-03-13 | 2019-05-03 | 常州君堃电子有限公司 | Nitrogen oxides ammonia gas sensor |
| CN111665289A (en) * | 2020-05-24 | 2020-09-15 | 苏州铟菲半导体科技有限公司 | Test device and preparation method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107076694A (en) * | 2014-09-18 | 2017-08-18 | 卡斯西部储备大学 | The sensor detected for VOC |
| JP6730069B2 (en) * | 2016-04-14 | 2020-07-29 | ローム株式会社 | Nitrogen oxide gas sensor and oxygen pump |
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2020
- 2020-10-21 CN CN202011132592.4A patent/CN112268938B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101889201A (en) * | 2007-10-09 | 2010-11-17 | 佛罗里达大学研究基金公司 | Multifunctional potentiometric gas sensor array with an integrated temperature control and temperature sensors |
| CN103645242A (en) * | 2013-12-04 | 2014-03-19 | 上海交通大学 | Ionizing sensor based on discharge electric field with micro-gap polarization structure |
| CN107407652A (en) * | 2015-03-11 | 2017-11-28 | 罗伯特·博世有限公司 | Manufacture method and corresponding gas sensor for gas sensor |
| CN109709194A (en) * | 2019-03-13 | 2019-05-03 | 常州君堃电子有限公司 | Nitrogen oxides ammonia integral sensor |
| CN109709193A (en) * | 2019-03-13 | 2019-05-03 | 常州君堃电子有限公司 | Nitrogen oxides ammonia gas sensor |
| CN111665289A (en) * | 2020-05-24 | 2020-09-15 | 苏州铟菲半导体科技有限公司 | Test device and preparation method thereof |
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| A tripolar-electrode ionization gas sensor using a carbon nanotube cathode for NO detection;等;Journal of Micromechanics and Microengineering;第28卷(第6期);1-6 * |
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