KR20150081705A - Gas Sensor - Google Patents

Gas Sensor Download PDF

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Publication number
KR20150081705A
KR20150081705A KR1020140001453A KR20140001453A KR20150081705A KR 20150081705 A KR20150081705 A KR 20150081705A KR 1020140001453 A KR1020140001453 A KR 1020140001453A KR 20140001453 A KR20140001453 A KR 20140001453A KR 20150081705 A KR20150081705 A KR 20150081705A
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KR
South Korea
Prior art keywords
gas
barrier layer
layer
compensation
electrode
Prior art date
Application number
KR1020140001453A
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Korean (ko)
Inventor
이상훈
박기용
황하룡
강현규
Original Assignee
(주)와이즈산전
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Priority to KR1020140001453A priority Critical patent/KR20150081705A/en
Publication of KR20150081705A publication Critical patent/KR20150081705A/en

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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

Abstract

A gas sensor is disclosed. The gas sensor comprises: an insulation substrate; a heater having a heating unit disposed on the insulation substrate; a sensing electrode spaced from the heating unit; a compensation electrode spaced from the heating unit; a sensing resistance unit formed between the heating unit and the sensing electrode; a compensation resistance unit formed between the heating unit and the compensation electrode; a gas reaction layer covering the sensing resistance unit and the compensation resistance unit; and a gas blocking layer formed on the gas reaction layer and covering the compensation resistance unit.

Description

[0001]

The present invention relates to a semiconductor gas sensor.

The gas sensor is a sensor for detecting the concentration of various gases such as methane or propane, combustible gas such as methane or propane, carbon dioxide, hydrogen, and the like. In accordance with the gas sensing method, a gas sensor, an electrochemical gas sensor, .

The semiconductor type gas sensor utilizes a property that the resistance changes when a ceramic material such as tin oxide (SnO 2 ) is exposed to a specific gas at a temperature of 300 degrees Celsius or more. The semiconductor gas sensor includes a gas reaction layer that reacts with the gas, a heater that heats the gas reaction layer, and a sensing resistor portion that senses a resistance value of the gas reaction layer.

However, in the conventional gas sensor, there is a problem that the resistance value of the gas-reactive layer varies depending on the change in the ambient temperature, and the concentration of the gas can not be accurately detected.

Further, two pairs of electrodes constituting the sensing circuit and the heater circuit are formed in different layers, resulting in a problem that the manufacturing cost increases.

The present invention provides a gas sensor in which the ratio of the resistance value of the gas reaction layer to the resistance value of the compensation resistance is kept constant according to temperature increase or decrease.

Also provided is a semiconductor gas sensor in which the sensing circuit is subjected to a power supply circuit to form an electrode pattern on the same layer, and the manufacturing cost is reduced by reducing the number of patterns.

A gas sensor according to one aspect of the present invention includes: an insulating substrate; A heater including a heat generating portion disposed on the insulating substrate; A sensing electrode spaced apart from the heating unit; A compensation electrode spaced apart from the heating unit; A sensing resistor formed between the heating unit and the sensing electrode; A compensation resistor formed between the heating unit and the compensation electrode; A gas reaction layer covering the sensing resistor section and the compensation resistor section; And a gas barrier layer formed on the gas reactive layer and covering the compensation resistor portion.

In the gas sensor according to one aspect of the present invention, the resistance ratio of the sensing resistor portion and the compensation resistor portion may have the same resistance ratio according to the temperature change.

 In the gas sensor according to one aspect of the present invention, the heating portion, the sense resistor portion, and the compensation resistor portion are disposed on the same plane.

In the gas sensor according to one aspect of the present invention, the heater includes a first power electrode connected to one end of the heat generating part, and a second power electrode connected to the other end of the heat generating part, And the compensation electrode is disposed apart from the other end of the heat generating unit.

In the gas sensor according to one feature of the present invention, the gas reaction layer is WO 3, SnO 2, TiO 2 , ZnO, In 2 O 3, Nb 2 O 5, Fe 2 O 3, CuO, NiO, Co 2 O 3 And Ga 2 O 3 .

In a gas sensor according to an aspect of the present invention, the gas barrier layer includes at least one selected from Al 2 O 3 , SiO 2 , Pb, Au, Ag, sodium silicate, and mixtures thereof.

In the gas sensor according to one aspect of the present invention, the density of the gas barrier monolayer may be 2.5 mg / cm < 3 > or higher.

In a gas sensor according to an aspect of the present invention, the thickness of the gas barrier layer may be 10 nm to 1000 nm.

A gas sensor according to one aspect of the present invention includes a barrier layer disposed between the gas responsive layer and the gas barrier layer.

In the gas sensor according to one aspect of the present invention, The barrier layer includes at least one selected from oxides, nitrides, and nonconductors.

In a gas sensor according to an aspect of the present invention, the thickness of the barrier layer may be 10 nm to 1000 nm.

In the gas sensor according to one aspect of the present invention, the gas-reactive layer includes a first gas-reactive layer disposed on the sensing resistor portion, and a second gas-responsive layer disposed on the compensating resistor portion, A single layer may be disposed on the second gas reactive layer.

A gas sensor according to one aspect of the present invention includes a barrier layer disposed between the second gas responsive layer and the gas barrier layer.

According to the present invention, the ratio of the resistance value of the gas-reactive layer to the resistance value of the compensation resistor is kept constant according to the increase or decrease of the temperature, and accurate gas detection becomes possible.

In addition, the sensing circuit is subject to the heater circuit to reduce the number of electrode patterns, and the sensing electrode and the heater electrode are formed in the same layer, thereby reducing manufacturing cost.

1 is a plan view of a gas sensor according to an embodiment of the present invention,
Fig. 2 is a sectional view in the AA direction in Fig. 1,
3 is an equivalent circuit diagram of a gas sensor according to an embodiment of the present invention,
Fig. 4 is a modification of Fig. 1,
5 is a cross-sectional view of a gas sensor according to another embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and a duplicate description thereof will be omitted.

FIG. 1 is a plan view of a gas sensor according to an embodiment of the present invention, FIG. 2 is a sectional view in the direction of arrow AA in FIG. 1, FIG. 3 is an equivalent circuit diagram of a gas sensor according to an embodiment of the present invention, 1 < / RTI >

1 and 2, a gas sensor according to the present invention includes a heater 20 including an insulating substrate 10, a heating unit 21 disposed on the insulating substrate 10, a heating unit 21 A sensing electrode 31 spaced apart from the sensing electrode 31, a compensating electrode 41 spaced apart from the heating unit 21, a sensing resistor A formed between the heating unit 21 and the sensing electrode 31, A compensating resistance portion B formed between the heating portion 21 and the compensating electrode 41, a gas reactive layer 50 and a gas barrier layer 60.

The insulating substrate 10 may be made of a material having low thermal conductivity while being insulating like a silicon nitride (Si 3 N 4 ) substrate or a silicon substrate having an oxide film. A heater 20, a sensing electrode 31, a compensating electrode 41, and a gas sensing layer 50 are formed on one surface of the insulating substrate 10. Therefore, the heater 20, the sensing electrode 31, the compensation electrode 41, and the gas sensing layer 50 are disposed on the same plane. A groove (not shown) corresponding to the area of the gas sensing layer 50 may be formed on the rear surface of the insulating substrate 10.

The heater 20 includes a first power supply electrode 22 and a second power supply electrode 23 disposed on one side of the insulating substrate 10 and one end 21a connected to the first power supply electrode 22, And the end 21d includes a heating unit 21 connected to the second power source electrode 23. The heat generating portion 21 is bent so as to have a circular shape and is heated by application of external power.

The sensing electrode 31 extends from the first electrode pad 30 disposed at the edge of the insulating substrate 10 and is spaced apart from the one end 21a of the heat generating portion 21. [ Therefore, the sensing resistor portion A is formed between the sensing electrode 31 and one end 21a of the heat generating portion 21. The resistance value of the sensing resistor section A changes in accordance with the concentration of the gas reacted by the gas reaction layer 50 and the temperature change of the gas reaction layer 50.

The compensation electrode 41 extends from the second electrode pad 40 disposed at the edge of the insulating substrate 10 and is spaced apart from the other end 21d of the heat generating portion 21. [ Therefore, the compensating resistance portion B is formed between the compensating electrode 41 and the other end 21d of the heat generating portion 21. The resistance of the compensating resistance portion B changes only by the temperature change of the gas-reactive layer 50. That is, the resistance value of the compensation resistance portion B does not change when the gas-reactive layer 50 reacts with the gas. The gas reaction layer 50 electrically connects the heating unit 21 with the sensing electrode 31 and the compensating electrode 41 to form a sensing resistor unit A and a compensation resistor unit B therein. The gas-responsive layer 50 may be fabricated and attached in the form of a pad or a film.

The gas reaction layer 50 may be configured to react with a reducing gas such as hydrogen (H 2 ), ammonia (NH 3 ), toluene (C 7 H 8 ), and carbon monoxide (CO) NO 2 ), sulfur dioxide (SO 2 ), sulfur trioxide (SO 3 ), or the like. Alternatively, the resistance value may be uniformly set or lowered when reacting with the gas.

The gas-reactive layer 50 may be formed of any one selected from WO 3 , SnO 2 , TiO 2 , ZnO, In 2 O 3 , Nb 2 O 5 , Fe 2 O 3 , CuO, NiO, Co 2 O 3 and Ga 2 O 3 Or more of the metal oxide or carbon nanotube. At this time, a catalyst such as platinum (Pt), palladium (Pd), vanadium (V), rhenium (Re), ferrous oxide (FeO)

The gas barrier layer 60 is formed on the gas-reactive layer 50 and covers the compensation resistor portion B. Specifically, the gas barrier layer 60 functions to shield the gas-reactive layer 50 formed on the compensation resistor portion B from reacting with the gas. Therefore, the resistance value of the compensating resistance portion B does not change due to the reaction of the gas reactive layer 50 and the gas, and the resistance value changes only by the temperature.

According to such a configuration, the resistance values of the sensing resistor section A and the compensation resistor section B change substantially when the temperature of the gas-reactive layer 50 is increased or decreased by the heat generating section 21. Therefore, even when the temperature changes, the resistance ratio between the sensing resistor portion A and the compensation resistor portion B becomes the same, so that the resistance value changed by the gas reaction can be accurately detected.

The gas barrier layer 60 may be selected from Al 2 O 3 , Pb, Au, Ag, sodium silicate, and mixtures thereof. That is, it can be used without restriction if it is a metal material which does not react with gas. The gas barrier layer 60 may be formed on the gas-reactive layer 50 by a method such as deposition, E-beam, PeCVD, atomic layer deposition (ALD) or the like, but is not limited thereto. For example, the gas barrier layer 60 may be made of a pad or film and attached to the gas-reactive layer 50.

The density of the gas barrier layer 60 is preferably 2.5 mg / cm 3 or more. When the density of the gas barrier layer 60 is less than 2.5 mg / cm 3, a gas having excellent permeability (for example, hydrogen gas, H 2 ) may pass through the gas barrier layer 60. In this case, since the permeated gas reacts with the gas-responsive layer 50 to change the resistance of the compensation resistance portion B, the accuracy of the sensor is degraded.

The thickness of the gas barrier layer 60 is preferably 5 nm to 1000 nm. When the thickness is less than 5 nm, deposition of a uniform thickness is difficult, and the gas barrier layer 60 is not partially deposited, resulting in gas penetration. When the thickness is 1000 nm, the thickness of the sensor becomes thick, Thereby providing a path through which the heat is transferred out. Therefore, power consumption can be increased,

Referring to FIG. 3, the sensor according to the present invention can calculate the gas concentration by detecting the output voltage Vout using the resistance ratio of the sensing resistor portion A and the compensation resistor portion B. Specifically, since the compensation resistance section B maintains a constant resistance value, the resistance value of the detection resistance section A can be calculated using the output voltage Vout of the compensation resistance section B. At this time, even when the temperature increases or decreases, the ratio of the resistance value of the compensation resistance portion B and the resistance value of the sensing resistor portion A is kept constant, and thus the error according to the ambient temperature decreases, .

In addition, the power source for sensing the resistance value of the sensing resistor section A can be simplified by using the power source Vin input to the heating section 21 of the heater 20. That is, the power source Vin flowing to the heat generating unit 21 is used as the input power source of the sensing circuit, so that the electrode pattern for inputting a separate power source to the sensing circuit can be omitted.

In addition, according to the present invention, there is an advantage that a thin film sensor can be manufactured because the manufacturing cost is reduced because an insulating layer or the like for insulating the heater is not required.

Referring to FIG. 4, a barrier layer 70 may be formed between the gas-reactive layer 50 and the gas barrier layer 60. The gas barrier layer 60 can change the physical properties (e.g., conductivity) of the gas reactive layer 50 in the process of being deposited on the gas reactive layer 50. Accordingly, in the present invention, the barrier layer 70 is formed as a thin film on the gas-reactive layer 50, thereby solving the problem that the gas barrier layer 60 changes the physical properties of the gas-reactive layer 50.

The barrier layer 70 can be applied to any type of insulating material. For example, the barrier layer 70 may include at least one selected from oxides, nitrides, and noble metals that can insulate the gas-reactive layer 50 from the gas-reactive layer 50.

The barrier layer 70 is preferably formed to a thickness of 5 nm to 1000 nm. When the thickness is less than 5 nm, deposition of a uniform thickness is difficult, and the barrier layer 70 is not partially deposited, causing a problem that the gas reaction layer 50 and the gas barrier layer 60 are in contact with each other. There is a problem that when a gas barrier layer is deposited due to a step difference, gaps are formed where gas can penetrate.

5 is a cross-sectional view of a gas sensor according to another embodiment of the present invention.

5, the gas reactive layer includes a first gas reactive layer 51 disposed on the sensing resistor portion A and a second gas reactive layer 52 disposed on the compensation resistor portion B do. Further, the gas barrier layer 60 is disposed on the second gas-reactive layer 52. At this time, a barrier layer may be further formed between the second gas reactive layer 52 and the gas barrier layer 60 as necessary.

According to the present invention, when the first gas-reactive layer 51 and the second gas-reactive layer 52 are separated and the first gas-reactive layer 51 reacts with the gas, the resistance value of the compensation resistance portion B It can fundamentally solve the changing problem.

Since the first gas reaction layer 51 and the second gas reaction layer 52 have the same physical properties, the resistance ratio between the sensing resistor portion A and the compensation resistor portion B is kept constant with temperature change . The configuration is the same as described above.

10: Insulated substrate
20: Heater
21:
30: sensing electrode
40: compensation electrode
50: gas reaction layer
60: Gas car fault
70: barrier layer
A:
B:

Claims (13)

An insulating substrate;
A heater including a heat generating portion disposed on the insulating substrate;
A sensing electrode spaced apart from the heating unit;
A compensation electrode spaced apart from the heating unit;
A sensing resistor formed between the heating unit and the sensing electrode;
A compensation resistor formed between the heating unit and the compensation electrode;
A gas reaction layer covering the sensing resistor section and the compensation resistor section; And
And a gas barrier layer formed on the gas reactive layer and covering the compensation resistor portion.
The method according to claim 1,
Wherein the resistance ratio of the sensing resistor portion and the compensation resistor portion has the same resistance ratio according to the temperature change.
The method according to claim 1,
Wherein the heat generating portion, the sense resistor portion, and the compensation resistor portion are disposed on the same plane.
The method according to claim 1,
The heater includes a first power electrode connected to one end of the heat generating unit and a second power electrode connected to the other end of the heat generating unit,
Wherein the sensing electrode is spaced apart from one end of the heat generating unit, and the compensating electrode is spaced apart from the other end of the heat generating unit.
The method according to claim 1,
The gas-reactive layer may contain at least one selected from WO 3 , SnO 2 , TiO 2 , ZnO, In 2 O 3 , Nb 2 O 5 , Fe 2 O 3 , CuO, NiO, Co 2 O 3 and Ga 2 O 3 Including a gas sensor.
The method according to claim 1,
The gas barrier layer may be an oxide and a nitride such as Al 2 O 3 , SiO 2 , Si 3 N 4 and sodium silicate, and may include at least one selected from metals such as Pb, Au, Al, Ag, Gas sensor.
The method according to claim 6,
Wherein the density of the gas barrier layer is 2.5 mg / cm < 3 >
The method according to claim 6,
Wherein the thickness of the gas barrier layer is 10 nm to 1000 nm.
The method according to claim 1,
And a barrier layer disposed between the gas responsive layer and the gas barrier layer.
10. The method of claim 9,
Wherein the barrier layer comprises at least one selected from oxides, nitrides, and nonconductors.
10. The method of claim 9,
Wherein the barrier layer has a thickness of 10 nm to 1000 nm.
An insulating substrate;
A heater including a heat generating portion disposed on the insulating substrate;
A sensing electrode spaced apart from the heating unit;
A compensation electrode spaced apart from the heating unit;
A sensing resistor formed between the heating unit and the sensing electrode;
A compensation resistor formed between the heating unit and the compensation electrode;
A gas reaction layer including a first gas reaction layer disposed on the sensing resistor unit and a second gas sensor layer disposed on the compensation resistor unit; And
And a gas barrier layer disposed on the second gas reactive layer.
13. The method of claim 12,
And a barrier layer disposed between the second gas responsive layer and the gas barrier layer.
KR1020140001453A 2014-01-06 2014-01-06 Gas Sensor KR20150081705A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110608980A (en) * 2018-06-15 2019-12-24 世钟工业株式会社 Exhaust gas particulate matter sensor
KR102625936B1 (en) * 2023-03-16 2024-01-17 주식회사 이너센서 Gas sensing device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110608980A (en) * 2018-06-15 2019-12-24 世钟工业株式会社 Exhaust gas particulate matter sensor
KR20190141995A (en) * 2018-06-15 2019-12-26 세종공업 주식회사 Particulater matter detection sensor
KR102625936B1 (en) * 2023-03-16 2024-01-17 주식회사 이너센서 Gas sensing device

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