WO2012033147A1 - 特定ガス濃度センサ - Google Patents
特定ガス濃度センサ Download PDFInfo
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- WO2012033147A1 WO2012033147A1 PCT/JP2011/070427 JP2011070427W WO2012033147A1 WO 2012033147 A1 WO2012033147 A1 WO 2012033147A1 JP 2011070427 W JP2011070427 W JP 2011070427W WO 2012033147 A1 WO2012033147 A1 WO 2012033147A1
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- thin film
- specific gas
- gas concentration
- temperature
- hydrogen
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- 239000007789 gas Substances 0.000 claims abstract description 491
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 358
- 239000010409 thin film Substances 0.000 claims abstract description 321
- 239000011358 absorbing material Substances 0.000 claims abstract description 142
- 238000010438 heat treatment Methods 0.000 claims abstract description 109
- 239000000758 substrate Substances 0.000 claims abstract description 101
- 238000006243 chemical reaction Methods 0.000 claims abstract description 56
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910001882 dioxygen Inorganic materials 0.000 claims abstract description 35
- 230000008859 change Effects 0.000 claims abstract description 33
- 238000005259 measurement Methods 0.000 claims abstract description 23
- 239000001257 hydrogen Substances 0.000 claims description 159
- 229910052739 hydrogen Inorganic materials 0.000 claims description 159
- 238000000034 method Methods 0.000 claims description 55
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 39
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 35
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 35
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- 238000002474 experimental method Methods 0.000 description 9
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- 238000005516 engineering process Methods 0.000 description 8
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- 230000002745 absorbent Effects 0.000 description 6
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- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
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- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
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- -1 metal hydride compound Chemical class 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
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- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- BWGNESOTFCXPMA-UHFFFAOYSA-N Dihydrogen disulfide Chemical compound SS BWGNESOTFCXPMA-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 229910017682 MgTi Inorganic materials 0.000 description 1
- 206010037660 Pyrexia Diseases 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
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- 239000002360 explosive Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
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- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
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- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 201000009240 nasopharyngitis Diseases 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
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- 229910052717 sulfur Inorganic materials 0.000 description 1
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- 230000002123 temporal effect Effects 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
- G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
- G01N25/4873—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation for a flowing, e.g. gas sample
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
- G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
- G01N25/4806—Details not adapted to a particular type of sample
- G01N25/4826—Details not adapted to a particular type of sample concerning the heating or cooling arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/005—H2
Definitions
- the present invention relates to a concentration sensor for a specific gas such as hydrogen gas or oxygen gas, and when the absorbing material of the specific gas absorbs hydrogen gas (H 2 ) or oxygen gas (O 2 ) (generally, it is absorbed in an atomic form). Performs an exothermic reaction, and an endothermic reaction when released, but the temperature rise based on the exothermic reaction at the time of absorption of a specific gas such as hydrogen (H 2 ) gas or oxygen gas (O 2 ) in the atmospheric gas
- the present invention relates to a specific gas concentration sensor that measures a specific gas concentration by measuring with a temperature sensor.
- gas sensors include a catalytic combustion type hydrogen gas detection sensor (see Patent Document 1) in which the temperature of a catalyst such as tin oxide and Pt is raised by a heater and combined with this catalytic action.
- some semiconductor gas sensors use a change in electrical resistance by utilizing a change in carrier density on the semiconductor surface due to reducing gas adsorption.
- a hydrogen storage alloy is fixed to one surface of a substrate and a strain gauge is attached to the other surface.
- a hydrogen detector (see Patent Document 2) is known that expands, detects strain of a substrate generated at that time with a strain gauge, and detects a hydrogen absorption amount based on the detected magnitude of the strain.
- oxygen (O) is absorbed (occluded) between layers of titanium disulfide (TiS 2 ), which is a layered crystal (intercalation), and the oxygen concentration can be measured from the resistance change at that time. ing.
- TiS 2 titanium disulfide
- a temperature sensor there are an absolute temperature sensor capable of measuring an absolute temperature and a temperature difference sensor capable of measuring only a temperature difference.
- an absolute temperature sensor capable of measuring absolute temperature a thermistor, a transistor thermistor using a transistor invented by the present applicant as a thermistor (Patent Document 4, Japanese Patent No. 3366590), and a diode thermistor using a diode as a thermistor (Patent Document 5) Patent No. 3583704), and there is an IC temperature sensor in which the temperature is linearly related to the forward voltage of the diode and the voltage between the emitter and base of the transistor.
- a temperature difference sensor that can measure only the temperature difference there are a thermocouple and a thermopile in which the output voltage is increased by connecting them in series.
- a microcapsule means for coating hydrogen storage alloy powder particles with a metal film, a temperature detection means by a thermocouple, a hydrogen storage alloy powder coated by a microcapsule means, and a thermocouple of a temperature detection means in a cap There has been proposed a hydrogen sensor that is mainly composed of a housed integrated means and an electronic control means using an electronic control unit including a power source (Patent Document 6).
- the inventor previously invented a “gas sensor element and a gas concentration measuring device using the same” (see Patent Document 7), and formed one or a plurality of temperature sensors on a thin film thermally separated from the substrate. And a gas-absorbing substance that absorbs the gas to be detected, and is intended to measure the concentration of hydrogen gas that is arranged and formed so that the temperature sensor can measure the temperature change associated with the absorption and heat generation during absorption and release of the gas to be detected
- a gas sensor element and gas concentration measuring device were proposed. Thereafter, the present invention is the result of finding the best mode suitable for various purposes through repeated experiments and improvements.
- JP 2006-201100 A Japanese Patent Laid-Open No. 10-73530 JP 2005-249405 A Japanese Patent No. 3366590 Japanese Patent No. 3583704 JP 2004-233097 A JP 2008-111182 A
- a catalytic reaction is used to burn at as low a temperature as possible.
- the surface state of the catalyst is important, and it is made porous to increase the surface area, or platinum (Pt In order to form a catalyst by dispersing fine particles of), repeated heating and cooling may cause changes in the catalyst characteristics, such as changes in the surface state of the catalyst over time or changes in the particle size of platinum (Pt).
- Pt platinum
- a sensor that uses the hydrogen storage alloy shown in Patent Document 2 and detects the hydrogen gas concentration from the magnitude of strain when absorbing hydrogen is suitable for detecting high concentration hydrogen.
- the senor disclosed in Patent Document 3 is a temperature control unit that controls a crystal resonator, which is a detection unit that detects a change in state (weight change) when hydrogen is absorbed, and a detection element at substantially the same temperature. It is necessary to incorporate a Peltier element, and there is a problem of high power consumption of the Peltier element and a problem that the sensor itself is inevitably enlarged.
- the microcapsule means of coating the hydrogen storage alloy powder particles with a metal film is necessary, and the hydrogen storage alloy is stored with hydrogen to undergo an initial grinding step. It is necessary to make the powder whose particle diameter is adjusted to about 20 ⁇ m, the joint of the two kinds of metal wire constituting the thermocouple, and the powder of the microcapsule of the hydrogen storage alloy are contained in the cap. , It is necessary to apply a pressure from the periphery of the cap made of a porous material that allows hydrogen gas to pass through, and it is necessary to integrate the hydrogen sensor into the caulking sensor mount, making it unsuitable for mass production and miniaturization.
- the heat capacity is large, and the time required for detecting the hydrogen gas concentration has been several minutes or more.
- the measurement time of the hydrogen gas concentration depends on the hydrogen gas concentration, For example, measurement within 1 second was impossible.
- the hydrogen storage alloys of LaNi-based and MgTi-based alloys of eutectic mixtures (eutectics) such as Cu, Ca, La, Mg, Ni, and Ti that are used are in a powder state. Uniform clothing is difficult, reacts with water vapor and oxidizes, loses hydrogen storage characteristics, and has a problem of rapid change over time.
- the reaction stops and depends on the heat capacity of the thin film 10 that is floating in the air to be the detection part, the temperature rise at the corner is completed within the thermal time constant ⁇ that is the thermal response time of the thin film of the detection part.
- Measurement of the hydrogen concentration is difficult as it is, and special measures are required. Even if the hydrogen gas concentration is increased in the air, the thermal conductivity of hydrogen will not increase even if the detection unit equipped with the hydrogen absorbing material is heated with the same power so that the hydrogen can start to burn. Because it is the largest in the gas, the heat radiation at the detection part also becomes intense. Rather, the temperature of this detection part begins to decrease, and the temperature due to heat generation based on the combustion of hydrogen during heater heating at a certain hydrogen gas concentration 3.
- the hydrogen concentration at which the temperature rises due to the temperature rise due to combustion during heating and the temperature rise due to exothermic reaction based on hydrogen absorption during the cooling process after stopping heating, compared to the hydrogen gas concentration in the air was found to exist. Accordingly, the hydrogen gas concentration cannot be determined only from the temperature rise due to heat generation, and it is necessary to measure the temperature rise using a different mechanism.
- FIG. 13 shows the output characteristics at the time of heating the heater in the region where the hydrogen gas concentration as the specific gas is high, using the specific gas concentration sensor element 100 having the initial structure of the present invention having the structure shown in FIG.
- the outline of the specific gas concentration sensor element 100 having the structure of FIG. 16 is as follows.
- a thin film 10a and a thin film 10b are formed by dividing a tip portion of a thin film 10 made of a cantilever-like n-type SOI layer formed by floating and floating in the air from the substrate 1 to form the thin film 10a.
- a heater 25 made of a nichrome thin film is formed in the common region 15 near the root where the thin film 10a and the thin film 10b are divided.
- the thin film 10a and the thin film 10b are each formed with a thermocouple 120 composed of an n-type SOI layer 12 and a nickel thin film formed thereon via a thermal oxide film 51, and the temperature difference between the thin film 10a and the thin film 10b is determined. This is a specific gas concentration sensor to be measured.
- Each thermocouple 120 uses the SOI layer 12 in common as a common ohmic electrode 60a and can be wired through the electrode pad 70.
- the common ohmic electrode 60a of the substrate 1 is a cold junction
- the thin film 10a and thin film 10b of each thermocouple 120 and the hot junction in the common region 15 are ohmic electrodes 60b, 61b, and 62b, respectively.
- the thin film 10a is formed with a hydrogen absorbing material 5 and serves as a detection sensor. Further, the thin film 10b is not formed with the hydrogen absorbing material 5, and serves as a reference sensor.
- FIG. 13 shows the result of an experiment using this prototype hydrogen gas specific gas concentration sensor.
- the thin film 2 is heated to the same power at about 150 ° C. (Of course, the thin film 10 a and the thin film 10 b at the tip are heated in the same manner). This is a case of an experiment of hydrogen gas concentration from 10% to 100% in the heating / cooling process at the time of heating and cooling, and shows characteristics when the hydrogen gas concentration is relatively high.
- the prototype thin film 10 (including the thin film 10a and the thin film 10b) has a cantilever shape, and the length from the substrate support portion to the tip of the thin film 10a or the thin film 10b is 5 millimeters (mm) long. Moreover, in order to prevent conduction of heat to the substrate, a slit 41 for thermal resistance is provided in the vicinity of the substrate support portion, and the thickness thereof is constant at about 10 micrometers ( ⁇ m). However, the thin film 10a and the thin film 10b are also formed in a wide shape and are enlarged. For this reason, since the thermal constant ⁇ in the pure air of the entire thin film 2 is as large as about 700 microseconds ( ⁇ Sec), the response is relatively slow. Of course, it is known that when the length is reduced, the thermal time constant ⁇ decreases in proportion to the square of the length.
- the experiment is performed by heating the heater by supplying a constant power so that the temperature is about 150 ° C.
- the hydrogen gas concentration is 10% or more. It can be seen that, although there is an exothermic reaction due to combustion, the effect of increasing the thermal conductivity of hydrogen increases and the temperature rise decreases as the value increases.
- the heater is equivalent. Although the temperature of the thin film 10a is higher in pure air even when heated, it is not shown in FIG.
- FIG. 14 shows the result of detecting a very low concentration of hydrogen gas in the vicinity of 0.1% (1000 ppm) using the prototyped specific gas concentration sensor identical to the data in FIG. It was found that the output of 0%, which is pure air containing no hydrogen gas, exceeded the concentration of 0.1% hydrogen gas and was reversed. This is considered to be an effect due to the large thermal conductivity of hydrogen, and indicates the limit of detection of low concentration hydrogen gas during heating. On the other hand, as shown in FIG.
- the present invention has been made in view of the above-mentioned problems, and in particular, has been improved as a specific gas such as hydrogen gas or oxygen gas as a gas to be detected of the gas sensor of Patent Document 7 which is the inventor's invention.
- a specific gas such as hydrogen gas or oxygen gas
- the specific gas concentration is measured.
- the hydrogen gas concentration measurement uses the absorption exothermic reaction of palladium (Pd), which absorbs only hydrogen
- the oxygen gas concentration measurement uses heat generation based on the intercalation of layered substances such as layered crystals.
- Another object of the present invention is to provide a specific gas concentration sensor with high accuracy and capable of widening the measurement concentration range of hydrogen gas and oxygen gas.
- a specific gas concentration sensor comprises a thin film 10 thermally separated from a substrate 1, a heater 25, a temperature sensor 20, and a specific gas absorbing material 5,
- the specific gas concentration sensor that allows the temperature sensor 20 to measure a temperature change accompanying heat generation during absorption of the specific gas in the atmospheric gas, the absorbed specific gas is removed from the absorbent 5 by heating the heater 25.
- the temperature sensor 20 is output at a time when a predetermined time more than the thermal time constant ⁇ of the thin film 10 when the specific gas of the heater 25 is not present is discharged after the heater is stopped. This is characterized in that the specific gas concentration in the atmospheric gas is obtained.
- the absorbing material 5 of a specific gas such as hydrogen or oxygen formed on a thin film (thin film suspended in the air) thermally separated from the substrate becomes minute as heat is generated when the specific gas is absorbed. Although the temperature rises, this is detected by a highly sensitive temperature sensor 20 formed in a thin film suspended in the air. As described above, when a specific gas is absorbed by the absorbent 5 and becomes in an equilibrium state, heat is generated.
- the reaction stops the temperature rise stops, and further, due to the specific gas concentration, the time until the temperature rise stops completely absorbed by the absorbing material, particularly,
- the specific gas is hydrogen
- the hydrogen gas concentration is about 5-10% (representing volume%) or more
- the temperature peak due to the exothermic reaction increases according to the hydrogen gas concentration.
- Hydrogen absorption in a short time Material will ceased completely absorbed by exothermic reaction, depending on the heat capacity of the detector, there is a problem that results in complete within the thermal time constant ⁇ is the thermal response time of the thin film detector.
- the specific gas is hydrogen, even if the hydrogen gas concentration is increased in the air, the same electric power that gives the temperature at which hydrogen combustion can be started because the thermal conductivity of hydrogen is the highest in the gas.
- the heating of the heater is stopped for a specific gas such as hydrogen or oxygen, instead of detecting the temperature rise due to the combustion heat due to the heating of the heater at 100 ° C. or higher.
- a specific gas such as hydrogen or oxygen
- the specific gas once released from the absorbing material 5 of the specific gas by heating begins to be absorbed, and the temperature rises based on the exothermic reaction at the time of absorption of the specific gas at that time
- the temperature slowly returns to the original atmospheric gas temperature (room temperature) as if the thermal time constant had increased.
- the specific gas is not absorbed even if the specific gas absorbing material 5 is mounted on the thin film 10 thermally separated from the substrate 1. Therefore, it is cooled with the original thermal time constant ⁇ without any reaction heat.
- the temperature increase ⁇ T from room temperature after the passage of the time about 4 times the thermal time constant ⁇ after the heating of the thin film 10 on which the specific gas absorbing material 5 is mounted is equal to that of the specific gas absorbing material 5. It can be considered that it depends only on the result of the exothermic reaction based on the specific gas absorption.
- the specific gas concentration sensor according to claim 2 of the present invention is a case where hydrogen gas is used as the specific gas.
- hydrogen gas When hydrogen gas is used as the specific gas, it has characteristics not found in other gases because hydrogen is the element with the smallest atomic radius. This is because when a specific gas concentration sensor is used as a hydrogen gas sensor, palladium (Pd) or the like can be used as a highly selective hydrogen gas sensor by utilizing the property that only hydrogen gas permeates. .
- the specific gas concentration sensor according to claim 3 of the present invention is a case where the hydrogen absorbing material 5 is a material containing platinum (Pt) or palladium (Pd) which is a chemically stable metal.
- hydrogen storage alloys which are single metals or alloys such as palladium (Pd), platinum (Pt), nickel (Ni), niobium (Nb), etc., as hydrogen absorption (including storage and adsorption) substances
- the reaction when hydrogen is absorbed is generally an exothermic reaction.
- the reaction heat of a hydrogen storage alloy of LaNi 5 is about 7 kcal per mole of hydrogen. It is a large value of about 0.048 kcal per gram of hydrogen.
- the metal hydride compound is heated to raise the temperature (at this time, an endothermic reaction occurs)
- hydrogen is released and the original hydrogen storage alloy is restored.
- the hydrogen absorbing material 5 absorbs and releases hydrogen reversibly, and a large amount of heat enters and leaves accordingly.
- the hydrogen absorbing material 5 When the hydrogen absorbing material 5 is formed into a thin film, it can be easily formed by sputtering, electron beam vapor deposition, etc., the surface area in contact with hydrogen gas is increased, the heat capacity is small and the high-speed response is achieved, and the thickness is controlled, This is advantageous because it can adjust the time until the absorption of hydrogen gas is completed, and therefore can adjust the temperature rise time due to an exothermic reaction after stopping heating, and can be a flat thin film without having to be porous or fine particles.
- the specific gas concentration sensor according to claim 4 of the present invention protects the absorbing material 5 so that a gas different from hydrogen that physically or chemically reacts with the absorbing material 5 of hydrogen is difficult to directly contact the absorbing material 5. This is the case when dressed with a film.
- the hydrogen absorbing material 5 When the hydrogen absorbing material 5 is palladium (Pa), for example, it may react with water vapor to cause a slight exothermic reaction. Thus, in order to prevent the hydrogen absorbing material 5 from reacting with a gas different from the physically or chemically reacting hydrogen, the hydrogen atom is thin because its radius is the smallest among all the atoms. It is preferable that the gas covers the absorbing material 5 with a protective film which is a film which can permeate the film, but cannot allow atoms and molecules of other gases to permeate.
- the protective film is preferably a hydrophobic substance. For example, a gold (Au) thin film is also suitable. It is desirable that the thickness and porosity of the protective film be adjusted so that the internal hydrogen absorbing material 5 does not come into direct contact with water vapor.
- the heater 25 is heated at a predetermined power, voltage, or current, stopped, and then cooled for a predetermined time greater than or equal to the thermal time constant ⁇ of the thin film 10. This is a case where the temperature of the temperature sensor 20 is measured at the elapse of time, and the hydrogen gas concentration is obtained in the hydrogen gas concentration range below the peak hydrogen gas concentration.
- the hydrogen gas has a certain hydrogen gas concentration even during heating at a temperature at which hydrogen combustion can start because of the large thermal conductivity of hydrogen. It has been found that the temperature due to heat generation due to the combustion of hydrogen has a maximum (peak), but heating is stopped, and even in the cooling process, hydrogen is generated by an exothermic reaction due to absorption of hydrogen into the absorbent 5 at a certain hydrogen gas concentration. It has been found that there is a hydrogen gas concentration at which the temperature of the temperature sensor 20 that measures the temperature of the absorbent 5 reaches the maximum (peak) (hereinafter, the peak hydrogen gas concentration is referred to as “peak hydrogen gas concentration”). I will call it).
- peak hydrogen gas concentration (peak hydrogen gas concentration)
- the ambient temperature, room temperature, and the temperature of the thin film 10 after a lapse of about four times the thermal time constant ⁇ after stopping heating.
- the temperature rise ⁇ T it is possible to measure the concentration of hydrogen gas in the air based on calibration data obtained in advance regarding the temperature rise ⁇ T and the hydrogen gas concentration.
- the output of the temperature sensor associated therewith is differentially amplified with the room temperature, using the zero method, The hydrogen gas concentration can be measured with high accuracy.
- the peak hydrogen gas concentration was about 5-10% according to the experiment, although it depends on the structure of the thin film 10 including the form of the hydrogen absorbing material 5 and the heating temperature.
- the thin film 10 itself floating in the air is formed in a cantilever shape or a bridge structure supporting both ends from the substrate 1, and a hydrogen absorbing material 5 is provided there.
- the thin film 10 floating in the air is divided so that it can be projected in a cantilever shape from the beam (beam) part connected to the substrate 1 for supporting the thin film 10, and further supported by a cross-linked structure across the cavity, It is better to place the hydrogen absorbing material 5 near the cantilever tip or near the center of the crosslinked structure.
- the cantilever or the bridge structure forming the hydrogen absorbing material 5 is not connected to the substrate or the beam (beam) portion so that the heat generated in the hydrogen absorbing material 5 does not easily escape to the substrate 1 through the beam (beam) portion.
- the heat generated by the hydrogen absorbing material 5 is difficult to escape to the substrate and the beam (beam) portion, and the temperature of the formed thin film portion is increased even with a small amount of generated heat.
- a heater 25 such as Joule heating is also formed on the thin film 10 so that hydrogen absorbed by the hydrogen absorbing material 5 can be released.
- a temperature sensor 20 is also formed so that the temperature of the thin film 10, particularly the minute temperature or temperature change during hydrogen absorption can be accurately measured by the hydrogen absorbing material 5. Therefore, the temperature sensor is a highly sensitive and highly accurate gas sensor by being provided in the thin film 10 where the hydrogen absorbing material 5 is formed.
- the thin film 10 on which the hydrogen absorbing material 5 is mounted measures the temperature rise ⁇ T from room temperature after about 4 times the thermal time constant ⁇ after stopping heating. Can be used to measure hydrogen gas concentration with high sensitivity and high accuracy.
- the thermal time constant ⁇ of the thin film 10 increases accordingly, and As a result, the response speed as a gas concentration sensor becomes slow.
- the thermal time constant ⁇ of the thin film 10 floating in the air is proportional to the square of the length of the same material and the same thickness.
- the thermal time constant ⁇ of a cantilever with a length of about 200 micrometers ( ⁇ m) made of an SOI layer is about 2 milliseconds in the air, although it depends on its thickness. Is measured in about 10 milliseconds, which can be said to be a high-speed response.
- a pn junction diode or transistor that can be made into an IC and can be made into a thin film can be used. Since these can be handled like a thermistor, the absolute temperature can be measured and the temperature of the thin film can be measured with extremely high sensitivity. However, when using a temperature difference sensor that is a thermocouple or a thermopile that forms a cold junction on the substrate 1 and forms a hot junction in a region of the thin film 10 where the hydrogen absorbing material 5 is provided or a region in the vicinity thereof.
- thermocouple structure Since the temperature difference between the room temperature and the hydrogen absorbing material 5 can be taken out as it is as an output, differential amplification is possible as it is, and the zero position method can be applied as it is, which is very convenient.
- These temperature sensors are small and inexpensive, because they are mass-productive.
- these temperature sensors can be used as micro heaters by applying Joule heating to the temperature sensors.
- the heater 25 may not necessarily be provided independently, and the temperature sensor 20 and the heater 25 may be used. Of course, for example, both the temperature sensor 20 and the heater 25 may be provided separately, and both may be formed in a thermocouple structure and used.
- the output of the temperature sensor is used in the atmospheric gas by using the output of the temperature sensor at the time when the time of the thermal time constant ⁇ or more of the thin film 10 when the hydrogen of the heater 25 is not present.
- the temperature at the time when the heating of the heater 25 is stopped is approximately 2.718 times (about 3 minutes).
- a reference thin film (reference sensor) that does not have the hydrogen absorbing material 5 is manufactured to have the same thermal time constant as the detection sensor of the thin film 10 that has the hydrogen absorbing material 5, and these are simultaneously manufactured.
- the atmospheric gas not necessarily air
- the specific gas concentration sensor according to claim 6 of the present invention includes a heater 26 and a temperature sensor 21 in the thin film 11 thermally separated from the substrate 1 when the specific gas is hydrogen. It is not provided or is inactive even if it is provided, and the heater 26 is heated under a predetermined power, voltage or current, and the temperature during heating of the heater 26 or a predetermined value immediately after the heating is stopped.
- the temperature measurement at the time of cooling during the passage of time, or the measurement of the elapsed time until reaching a predetermined temperature is performed using the temperature sensor 21, and the difference in thermal conductivity due to the hydrogen gas concentration in the atmospheric gas.
- the specific gas as a heat conduction type sensor capable of measuring the hydrogen gas concentration of at least 3% and up to 100% by using the output of the temperature sensor 21 or the change of the output based on A case having a degree sensor.
- the specific gas concentration sensor when hydrogen is used as the specific gas described above includes the heater 25, the temperature sensor 20, and the hydrogen absorbing material 5 in the thin film 10, and has a hydrogen gas concentration of approximately 10% or less.
- the hydrogen absorbing material 5 absorbed the hydrogen gas, and the temperature rise based on the heat generation was measured to measure the hydrogen gas concentration.
- the specific gas concentration sensor which is a different mechanism, that is, a specific gas concentration sensor as a so-called heat conduction type sensor that utilizes the difference in heat dissipation due to the hydrogen gas concentration of the heated thin film 11 can also be used together
- the gas concentration sensor can detect a hydrogen gas concentration widely from 0% to 100%.
- the hydrogen gas concentration by the temperature measurement alone shows a peak in the characteristics of the hydrogen gas concentration and the measured temperature in the vicinity of the hydrogen absorbing material 5 due to the large thermal conductivity of the hydrogen gas (existence of the peak hydrogen gas concentration)
- the hydrogen gas concentration is in the vicinity of 5-10%). Therefore, the same temperature increase exists in the hydrogen gas concentration on both sides of this peak, and it was impossible to identify the hydrogen gas concentration only by measuring the temperature increase once after the heating was stopped. For this reason, it is necessary to use a hydrogen gas concentration measurement method with a different mechanism such as a heat conduction type sensor.
- the heat radiation from the thin film 11 also increases in proportion to the hydrogen gas concentration, so that it cools quickly and the thermal time constant decreases.
- the thin film 11 there is no exothermic reaction based on the absorption of hydrogen gas in the hydrogen absorbing material 5, so the value of the saturation temperature during heating of the thin film 11 by the heater 26 according to the hydrogen gas concentration
- a hydrogen gas concentration of 1% or more can be accurately measured by measuring after the elapse of a predetermined time in the cooling process or the elapse of time to reach a predetermined temperature.
- the hydrogen gas concentration can be measured from the temperature measurement at the time of cooling when a predetermined time has elapsed from immediately after the heating is stopped. If it is possible to measure a hydrogen gas concentration of at least%, it is sufficient.
- the specific gas concentration sensor according to claim 7 of the present invention heats the heater 25 under a predetermined power, voltage, or current to estimate a rough range of the hydrogen gas concentration in the atmospheric gas. This is a case where the output information of the temperature sensor 20 based on the combustion of hydrogen during heating is also made available.
- the mechanism of the specific gas concentration sensor described in claims 1 and 2 is different in the specific gas concentration of this catalytic combustion type.
- the sensor is also used in combination to determine whether the hydrogen gas concentration is in a range larger than this peak hydrogen gas concentration or a hydrogen gas concentration in a smaller range. In this way, the large output of the temperature rise due to hydrogen combustion possessed by this catalytic combustion type specific gas concentration sensor can be used as confirmation of the presence of hydrogen gas and as information on the rough range of the hydrogen gas concentration. It is what I did.
- the specific gas concentration sensor according to claim 8 of the present invention is a case where oxygen gas is used as the specific gas.
- Oxygen gas unlike hydrogen gas, cannot use the special property that the atomic radius of oxygen is the smallest atomic radius like hydrogen. However, a reaction (intercalation reaction) that occludes (absorbs) highly active oxygen between layers such as layered crystals can be used.
- the specific gas concentration sensor according to claim 9 of the present invention includes a layered material as the oxygen absorbing material 5 and uses an exothermic reaction accompanying oxygen intercalation reaction in the layered material.
- volume expansion can be measured with a strain gauge, etc., but there are problems such as the strain gauge formation method, correction problems due to changes in ambient temperature, and hysteresis.
- electrical resistance there are problems with ohmic contacts, insulation
- a temperature difference sensor such as a thermocouple or a thermopile. That led to
- a layered material such as a layered crystal is suitable as the oxygen absorbing material 5, and among these, a titanium disulfide crystal is suitable for an oxygen intercalation reaction.
- the titanium disulfide crystal spontaneously takes in oxygen atoms between the layered layers even at room temperature (oxygen storage), and enters a thermal equilibrium state. Since an exothermic reaction occurs during this oxygen storage, the temperature rise at this time is measured with a temperature difference sensor, and the oxygen concentration in the ambient gas is calculated based on calibration data associated with the ambient temperature prepared in advance. It is. This method is the same as the temperature difference detection based on the exothermic reaction in the hydrogen absorbing material 5 as the hydrogen gas sensor described above.
- the thin film 10 is divided into at least two thin films 10a and 10b, and a thin film is formed in a common region near the root of the division of the thin films 10a and 10b.
- a heater 25 that can heat the thin film 10b and the thin film 10b equally is provided.
- the thin film 10a includes the temperature sensor 20 and the hydrogen absorbing material 5
- the thin film 10b includes the temperature sensor 21, but the hydrogen absorbing material. 5 is not provided or is inactive even if it is provided so that the thin film 10a can be used as a hydrogen detection sensor and the thin film 10b can be used as a reference sensor so that a temperature difference between the thin film 10a and the thin film 10b can be detected. This is the case where the output information of this temperature difference can be used.
- the thin film 10 is cantilevered and divided into two thin films 10a and 10b, and one cantilevered thin film 10a includes a specific gas absorbing substance 5 and a temperature sensor 20 as a specific gas detection sensor.
- the other cantilever-shaped thin film 10b is mainly used as a reference sensor for comparison with a detection sensor, and the thin film 10b is not provided with the absorbing substance 5 of a specific gas, but the detection sensor It is better to make it substantially equal to the mass in the thin film 10a.
- the specific gas absorbing material 5 on the thin film 10b is covered with a film that does not react with the specific gas so as not to come into contact with the specific gas. It is necessary to.
- the thin film 10a and the thin film 10b have substantially the same shape, and the thin film 10b is formed on the thin film 10a as necessary. This is a case where a material having a heat capacity equivalent to that of the gas absorbing material 5 is formed as the balance film 6 so that the thermal response in the atmospheric gas containing no specific gas is the same.
- the thin film 10b that does not have the specific gas absorbing material 5 or is deactivated even if it has the specific gas absorbing material 5 can be used as a reference sensor for the thin film 10a having the specific gas absorbing material 5.
- a specific gas absorbing substance (so as to have exactly the same thermal time constant ⁇ ).
- a material having a heat capacity equivalent to 5) is formed as the balance film 6.
- a specific gas does not exist in an atmospheric gas such as air or nitrogen gas.
- an atmospheric gas such as air or nitrogen gas.
- the temperature sensor 20 and the temperature sensor 21 respectively formed on the thin film 10a and the thin film 10b are heated by the heater 25 common to them, the temperature is simultaneously increased to the same output, and the difference between these outputs is It will be zero.
- the specific gas is present in the atmospheric gas, especially when the specific gas is a flammable gas such as hydrogen gas, the thin film 10a provided with the absorbing material 5 is heated to a certain temperature during the heater heating.
- the differential output and the specific gas concentration are obtained in advance by differential amplification of the output voltages of the temperature sensor 20 and the temperature sensor 21 formed on the thin film 10a and the thin film 10b, respectively.
- the specific gas concentration is obtained by using some calibration data.
- the thin film 10a and the thin film 10b have exactly the same heat capacity, it should be possible to easily obtain the specific gas concentration from the relationship between the differential amplification output and the specific gas concentration data at any point in the cooling process.
- the thermal time constant is often different due to the presence of some heat capacity and the difference in thermal conductivity in the thin film 10, and the differential after the elapse of the original thermal time constant ⁇ It has been found that the specific gas concentration can be measured stably and with good reproducibility by using the amplified output.
- the specific gas is hydrogen gas
- the concentration exceeds 5% the thermal conductivity of the hydrogen gas is large, so that the effect can be seen, and the temperature increases as the hydrogen gas concentration increases even with the same heater heating.
- the thin film 10 is divided into cantilever-like protrusions as the thin film 10a and the thin film 10b.
- the thin film 10a and the thin film 10b may be extended to form a cross-linked structure. it can.
- the temperature sensors 20 and 21 are equally formed in the vicinity of the central portion of the cross-linked structure where the temperature rise is greatest when heated as the cross-linked thin film 10, and the vicinity of the central portion of the thin film 10 of the cross-linked structure of one thin film 10a It is preferable to form the absorption material 5 of the specific gas and to form the temperature sensor 20 so that the temperature of the absorption material 5 of the specific gas can be measured.
- the mass of the specific gas absorbing material 5 is different. Furthermore, when the absorbing material 5 of the specific gas is made of a metal such as palladium Pd, the thermal conductivity of the thin film 10a itself is different, so that the heating / cooling can be performed even in an atmospheric gas in which no specific gas exists. The thermal response is different, making it difficult to handle the thin film 10b as a complete reference sensor.
- a material having a heat capacity equivalent to that of the absorbing material 5 of the specific gas is formed on the thin film 10b as the balance film 6, and the thermal response at the time of heating / cooling is substantially the same even in the atmospheric gas in which the specific gas does not exist. It is good to become. Also in this case, it is important to control the thickness and area of the balance film 6 so as to be equivalent to the specific gas absorbing material 5 formed on the thin film 10a including the thermal conductivity.
- differential amplification of the temperature outputs of the thin film 10a and the thin film 10b may be performed. This is because if the thermal time constant ⁇ of 4 times or more after the heating is stopped, the thin film 10b is completely cooled and returned to room temperature.
- the temperature sensor 21 of the thin film 10b is a thermocouple, its output voltage Is zero, and the differential amplification of the outputs of the thin film 10a and the thin film 10b is necessary for measuring the specific gas concentration even during the heating or in the cooling process immediately after stopping the heating. .
- the thin film 11 is formed by thermal separation from the substrate 1 separately from the thin film 10, and the thin film 10 does not have the specific gas absorbing material 5. This is a case where the shape is equivalent.
- the temperature sensor may be an absolute temperature sensor such as a platinum resistor, or a temperature difference sensor such as a thermocouple or a thermopile. These temperature sensors can also be used as heaters by Joule heating. Of course, the temperature difference sensor can be used only as a heater, not as a temperature difference sensor.
- the thin film 11 is not provided on the substrate 1 independently of the thin film 10, but the thin film 10 is divided into the thin film 10 a and the thin film 10 b that do not have or have the hydrogen absorbing material 5.
- the thin film 10b that is made inactive by coating with an inert film or the like that does not pass hydrogen and that is substantially equivalent to a state that does not have the hydrogen absorbing material 5 is used as the thin film 11. You may do it. In this case, it can be a hydrogen gas sensor as a specific gas concentration sensor that is more compact. However, since the thin film 10a is provided with the absorbing material 5 of the specific gas, the thin film 10 is heated due to the exothermic reaction based on the absorption of the specific gas into the absorbing material 5 of the specific gas.
- the temperature sensor 20 and the temperature sensor 21 provided in the thin film 10a and the thin film 10b, respectively, are temperature difference sensors such as thermocouples, and the common contact (the warm contact point) in the common region near the base of the division of the thin film 10a and the thin film 10b Or a cold junction), and the temperature and temperature difference between the thin film 10a and the thin film 10b may be measured with reference to this.
- the specific gas concentration sensor according to claim 13 of the present invention is a case where the temperature sensors 20 and 21 are temperature difference sensors.
- the temperature difference sensor includes a thermocouple and a thermopile.
- the temperature difference sensor is suitable, for example, for measuring a temperature difference from the temperature of an absolute temperature sensor formed on the substrate 1 as a reference.
- the temperature sensor 20 provided in the thin film 10 provided with the absorbing material 5 of the specific gas such as hydrogen or oxygen is only for the temperature rise from the atmospheric gas based on the exothermic reaction with the absorbing material 5 of the specific gas in the atmospheric gas such as air. It is better to configure so that it can be detected. This is because it is necessary to detect the temperature rise from the atmospheric gas temperature (room temperature) based on the exothermic reaction caused by the specific gas absorption between the temperature sensor for detecting the temperature of the atmospheric gas and the absorbing material 5 of the specific gas that is the detection target gas. If the temperature sensor is an absolute temperature sensor, there are two temperature sensors: a temperature sensor that measures the temperature of the atmosphere gas, and a temperature sensor 20 that measures the temperature rise from the atmosphere gas based on the exothermic reaction.
- this hot junction is connected to the specific gas.
- a temperature difference detection sensor such as a thermocouple or a thermopile that can detect only a temperature change based on the reaction of the specific gas that is the detection target gas with the absorbent 5, for example.
- the specific gas concentration sensor according to the fourteenth aspect of the present invention is a case where a current is supplied to the temperature sensors 20 and 21 to be used as the heaters 25 and 26.
- Joule heating is used here even if the temperature sensors 20 and 21 are absolute temperature sensors such as platinum, semiconductor resistors, diodes and transistors, or temperature difference sensors such as thermocouples. can do. In this case, it can be used as a temperature sensor / heater, or it can be manufactured in the same process as the required temperature sensor. A compact and inexpensive specific gas concentration sensor can be provided.
- the specific gas concentration sensor according to claim 15 of the present invention is a case where an absolute temperature sensor is provided on the substrate for measuring the temperature of the atmospheric gas.
- the amount of absorption of the specific gas into the absorbing material 5 and the amount of heat generated thereby depend on the ambient gas temperature. In general, the lower the ambient gas temperature, the greater the amount of absorption of the specific gas, and the more heat is generated. Further, for example, when the specific gas is hydrogen gas, heat generation based on catalytic combustion of hydrogen gas occurs at about 100 ° C., and it is necessary to know the atmospheric gas temperature. Therefore, a temperature sensor for measuring the temperature of the atmospheric gas is required, and the substrate 1 is exposed to the atmospheric gas temperature for a long time. When the temperature sensors 20 and 21 are temperature difference sensors, the cold junction is applied to the substrate. For example, it is preferable to provide the substrate 1 with an absolute temperature sensor for measuring the temperature of the atmospheric gas. As described above, the absolute temperature sensor includes platinum, a semiconductor resistor, a diode, a transistor, and the like.
- the substrate 1 is a semiconductor substrate, and the thin film 10 and the thin film 11 formed through a sacrificial layer formed above the substrate 1 are formed. This is a case where the layer is etched away to form a cavity, and an electronic circuit can be formed on the substrate 1 as necessary.
- various electronic circuits such as an OP amplifier, a memory circuit, an arithmetic circuit, a heater drive circuit, and a display circuit can be formed here by a mature semiconductor IC technology. If the substrate itself is three-dimensionally processed by MEMS technology using anisotropic etching technology etc., the space for forming these electronic IC circuits will be insufficient, and the substrate will tend to be large, Further, since the anisotropic etching or the like is performed after the formation of the IC electronic circuit in the process, the wiring of the IC electronic circuit or the like may not be able to withstand these anisotropic etching chemicals.
- the thin film 10 or the thin film 11 that is thermally separated from the substrate in the form of being stacked on the substrate and floating in the stacked shape. And forming a thin film of the temperature sensors 20 and 21 and the heater 25 and the absorbing material 5 of the specific gas, and forming an IC electronic circuit also on a substrate (for example, a single crystal silicon substrate) which is underneath this. Further, it is effective in terms of area, and a compact specific gas concentration sensor can be provided.
- the thin film 10 and the thin film 11 are formed of polysilicon, it is possible to easily insulate an oxide film or the like, it can be formed like a thermocouple as a temperature difference sensor, and the temperature sensor can be used as a heater.
- the gas absorbing material 5 palladium (Pd) and platinum (Pt) can also be easily formed by a dry process using a known MEMS technique, such as sputtering.
- the specific gas concentration sensor according to claim 17 of the present invention is a case where the specific gas concentration sensor element is covered with a cap having a mesh structure to block the air flow, and if necessary, an explosion-proof type.
- the specific gas concentration sensor is a heat conduction type sensor, if there is an air flow, the heat from the heater due to the air flow is taken away, so an accurate specific gas concentration cannot be measured. Therefore, even if there is a certain amount of air current, the specific gas concentration sensor element can be covered with a cap having a mesh structure to block the air current, thereby providing the same effect as when the air current is interrupted.
- the specific gas is a combustible gas such as hydrogen
- it is ignited by heating the heater, and there is a risk of explosion depending on its concentration.
- a metal mesh or the like explosion-proof type
- the specific gas concentration sensor of the present invention measures the temperature of the thin film floating in the air, so that the influence of the air flow is extremely disliked. Therefore, although the airflow is blocked, it is necessary for the hydrogen gas to reach the detection unit smoothly.
- the concentration of hydrogen gas in the air is explosive in a wide range of 4.0-75.0%.
- the heater 25 releases the hydrogen gas from the hydrogen absorbing material 5 or heats the heater as a heat conduction type sensor.
- a mesh-structured cap that is porous such as metal that blocks airflow is suitable.
- the cap having the mesh structure shares the airflow blocking effect and the achievement of the explosion-proof type.
- the specific gas concentration sensor according to claim 18 of the present invention is a case where at least an electronic circuit is provided and the specific gas concentration in the atmospheric gas is measured so that the heaters 25 and 26 can be heated in a predetermined cycle. is there.
- the specific gas concentration sensor of the present invention is provided with electronic circuits such as an amplifier circuit, an arithmetic circuit, and a memory circuit, and the heaters 25 and 26 are set in accordance with a predetermined program by clock pulse generation or transistors. It includes a modularized specific gas concentration sensor that can be heated in a cycle, and furthermore, it is equipped with a main body of this modularized specific gas concentration sensor so that the specific gas concentration can also be displayed. It refers to a specific gas concentration sensor equipped with a display circuit.
- the electronic circuit may be provided on the substrate by adopting a semiconductor substrate as the substrate, or may be provided close to the specific gas concentration sensor element and modularized.
- the predetermined cycle is not necessarily a constant cycle, and may be repeated.
- the absorbing material 5 of the specific gas is formed on the thin film 10 suspended in the air from the substrate.
- the high-speed operation is about several milliseconds. Therefore, since the absorbing substance (5) for the specific gas is also in the form of a thin film, the process of releasing the specific gas by heating the heater may be 10 milliseconds in this case. Also, in this case of the cooling process, 10 milliseconds is sufficient, and even if the heating / cooling process is included, about 30 milliseconds is sufficient. It can be provided.
- the thin film 10 may be heated to a predetermined steady temperature, and the thin film 10 or the thin film 11 may be heated by the heater periodically at a predetermined cycle up to a predetermined temperature based on this temperature.
- the specific gas absorbing material 5 formed in the specific gas concentration sensor is heated at room temperature, which is the temperature of the atmospheric gas, or at a predetermined power from a predetermined temperature, and the heating is stopped.
- the temperature changes based on the adsorption / desorption process of the specific gas in the absorbent 5 at that time, in particular, the temperature rise, the temporal change in temperature, and the equivalent thermal time constant associated therewith.
- a specific gas concentration is detected by measuring a change or the like.
- the present invention promotes the desorption of the specific gas from the absorbing material 5 of the specific gas by heating the thin film 10 with the heater 25 or additional heating, and returns the initial state to the initial state. Is what you expect. Moreover, since the room temperature which is the temperature of atmospheric gas changes for every measurement by the environment, it is necessary to measure this temperature. Absorption including absorption and adsorption of a specific gas is larger at a lower temperature, but in order to make the initial state or initial conditions constant, a predetermined temperature (e.g., slightly higher than the ambient temperature of the place where measurement is normally performed) , 30 ° C.), the thin film 10 may be heated by the heater 25.
- a predetermined temperature e.g., slightly higher than the ambient temperature of the place where measurement is normally performed
- the thin film 10 thermally separated from the substrate is provided with the temperature sensor 20 and the specific gas absorbing material 5 that absorbs the specific gas. Since the temperature change is increased and the temperature change can be measured with a highly sensitive and accurate temperature sensor, there is an advantage that a specific gas concentration sensor with high sensitivity and accuracy can be provided. .
- the absorbing material 5 of the specific gas can be formed in a thin film, so that the surface area in contact with the specific gas is increased, the heat capacity is small, and the high-speed response is provided. Since the specific gas absorbs and releases the specific gas at the absorption material 5 at a high speed, there is an advantage that a high-speed response is obtained. In addition, the specific gas absorbing material 5 does not necessarily need to be porous, and since it is flat, there is an advantage that a specific gas concentration sensor with little change with time can be provided.
- the temperature rise of the thin film 10 due to the exothermic reaction heat based on the absorption of the specific gas in the cooling process after the specific gas is released from the absorbing material 5 of the specific gas by heating with the heater is specified. Since it can be measured after the elapse of a predetermined time after the original thermal time constant ⁇ when gas is not present (preferably 4 times or more of ⁇ ), it can be applied to the zero position method which can be very highly accurate. It became possible to measure a very low concentration of a specific gas. In particular, when the specific gas is hydrogen gas, highly accurate concentration measurement can be performed below the “peak hydrogen gas concentration” (region of about 5-10%).
- the hydrogen gas as the specific gas has the highest thermal conductivity. Therefore, if the hydrogen concentration is about 10% or more under the influence, the hydrogen concentration is large even during heating and combustion. Rather, there is a phenomenon that the temperature rise is reduced. Further, even during the cooling process or at the end of cooling, the hydrogen absorbing material 5 has an increase in the temperature of the thin film 10 due to exothermic reaction heat when it absorbs hydrogen. And having a “peak hydrogen gas concentration” that has a peak in the temperature rise of the hydrogen absorbing material 5 at a certain hydrogen gas concentration, due to the effect of the difference in the absorption rate due to the hydrogen concentration, It is known from experiments.
- a heat conduction type specific gas concentration sensor for measuring a wide range of hydrogen gas concentrations including this "peak hydrogen gas concentration" can be used together, so a wide range of hydrogen gas concentrations from 0% to 100% can be obtained. There is an advantage that measurement can be performed with high accuracy.
- the temperature sensor when the heater 25, the specific gas absorbing material 5 and the temperature sensor 20 are formed in the cantilever-like thin film 10, the temperature sensor is formed at the tip of the thin film 10 where the temperature changes most drastically. Can do. Therefore, there is an advantage that a highly sensitive specific gas concentration sensor can be provided. In particular, when a sensor capable of detecting only a temperature difference such as a thermopile or a thermocouple is used as the temperature sensor 20, a reference sensor that does not form the specific gas absorbing material 5 is not necessarily required. There is an advantage that the specific gas concentration can be measured with only one cantilever-like thin film 10 forming a temperature sensor on the basis of the temperature when the specific gas is not present.
- the temperature sensor 20 can be used as a heater / temperature sensor by Joule heating.
- the temperature sensor 20 is used as a temperature difference sensor in the cooling process after being heated using the heater 25, so that the zero method can be applied as it is. It is.
- the specific gas concentration sensor when the heater 25, the specific gas absorbing material 5 and the temperature sensor 20 are formed on the thin film 10 having a cross-linked structure, wiring to the substrate 1 can be drawn from both ends of the cross-linked structure. There is an advantage that crowding and electrical separation are facilitated and the thermal time constant is small, so that high-speed response can be achieved and the strength of the thin film 10 can be easily increased.
- the thin film 10 can be divided into two thin films having the same shape, and one thin film 10a is provided with the absorbing substance 5 of the specific gas and the temperature sensor 20, and the detection sensor.
- the other thin film 10b is provided with a temperature sensor 21 and further formed with a balance film as necessary to serve as a reference sensor.
- a heater 25 mounted in a common area of these two thin films is used for the predetermined thin film 10b. Since the thin film 10 is heated to a temperature, the temperature increase associated with the endothermic absorption of the specific gas in the specific gas absorbing material 5 is differentially amplified, and the zero position method is used for high sensitivity, high accuracy, and easy identification There is an advantage that the gas concentration can be measured.
- the specific gas concentration sensor of the present invention uses the specific gas absorbing material 5 (for example, Pd for hydrogen gas, titanium disulfide for oxygen gas, etc. as the specific gas) that can absorb and occlude only the specific gas. Very selective for other gases.
- hydrogen gas When hydrogen gas is used as the specific gas with the specific gas concentration sensor of the present invention, it does not require the presence of a specific gas such as oxygen as in the catalytic combustion type gas sensor, and does not contain general oxygen, for example, nitrogen.
- the hydrogen gas concentration in atmospheric gas such as gas, argon gas, methane gas, etc. can be measured with high sensitivity and high accuracy, and it can be compact and portable. It can also be provided as a total.
- a noble metal hydrogen absorbing material 5 such as Pd or Pt, it is chemically stable, such as not oxidized, and therefore has an advantage that it can provide a highly reliable hydrogen gas concentration sensor with very little change over time. is there.
- the absolute temperature sensor is always exposed to the atmospheric gas, and is provided on a substrate having a temperature substantially equal to the room temperature that is the temperature of the atmospheric gas. It can be used as room temperature, which is a temperature.
- room temperature which is a temperature.
- the substrate can be used as the reference temperature of the cold junction, and only the temperature rise from this temperature can be accurately measured.
- the measurement value of the reference temperature is necessary for correction in the measurement of the specific gas concentration.
- a highly accurate specific gas concentration sensor can be provided.
- the substrate is formed of a semiconductor, there is an advantage that diodes and other semiconductor temperature sensors can be formed by mature IC technology.
- the thin film 10 floating in the air is heated by the thin film heater 25 mounted on the thin film 10, there is an advantage that it can be heated and cooled at high speed with low power consumption,
- the thin gas-like absorbing material 5 of the specific gas is used, there is an advantage that the specific gas can be easily completely discharged by heating and can be performed at a high speed.
- the substrate 1 can be a semiconductor substrate, and the thin film 10 and the thin film 11 formed through a sacrificial layer formed above the substrate 1 can be used. This sacrificial layer is removed by etching. Since a cavity is formed and an electronic circuit can be formed on the substrate 1 as necessary, there is an advantage that an electronic circuit can be effectively formed even on a small semiconductor substrate and a compact specific gas concentration sensor can be provided. .
- the specific gas concentration sensor element can be formed in a small size of, for example, about 1 mm square, and can be mass-produced by MEMS technology. Therefore, an extremely small cap having a porous mesh structure is attached. There is an advantage that an inexpensive explosion-proof specific gas concentration sensor can be provided.
- Example 1 is a schematic sectional view taken along line XX in FIG. 1.
- Example 1 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 portion which is a feature of the specific gas concentration sensor of the present invention.
- Example 2 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 portion which is a feature of the specific gas concentration sensor of the present invention.
- Example 2 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 portion which is a feature of the specific gas concentration sensor of the present invention.
- Example 3 is a schematic sectional view taken along line XX in FIG. 5.
- Example 3 is a schematic sectional view taken along line XX in FIG. 5.
- FIG. 6 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 portion which is a feature of the specific gas concentration sensor of the present invention.
- Example 4 It is the cross-sectional schematic which shows one Example of the specific gas concentration sensor element 100 part used as the characteristic of the specific gas concentration sensor of this invention.
- Example 5 FIG. 6 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 portion which is a feature of the specific gas concentration sensor of the present invention.
- Example 6 It is the cross-sectional schematic which shows one Example of the specific gas concentration sensor package which made the specific gas concentration sensor of this invention explosion-proof type, and is a case where it is set as hydrogen gas as specific gas.
- Example 7 It is the block diagram which showed one Example of the specific gas concentration sensor of this invention.
- Example 8) It is the block diagram which showed another Example of the specific gas concentration sensor of this invention.
- Example 9 It is the output characteristic of the experimental data at the time of heater heating in the area
- the specific gas concentration sensor element which is the basis of the specific gas concentration sensor of the present invention, can be formed on a silicon (Si) substrate on which an IC can also be formed using mature semiconductor integration technology and MEMS technology.
- Si silicon
- MEMS technology MEMS technology
- a case where the specific gas concentration sensor element is manufactured using a silicon (Si) substrate will be described in detail below based on an embodiment with reference to the drawings.
- a specific gas concentration sensor used as a specific gas concentration meter when the specific gas concentration sensor of the present invention is modularized will be described with reference to the block diagram.
- FIG. 1 shows a case where a specific gas concentration sensor according to the present invention detects a specific gas such as hydrogen gas or oxygen gas, and shows a chip-shaped specific gas concentration sensor element 100 manufactured using a silicon single crystal.
- FIG. 2 is a schematic plan view showing an embodiment, and FIG. 2 is a schematic cross-sectional view taken along the line XX.
- an SOI substrate is used as the substrate 1
- one thin film 10 having a structure floating in the air for thermal separation from the substrate 1 and a thin film 11 as the other thin film are:
- the substrate 1 has a cantilever shape and is formed in the same shape.
- One thin film 10 includes a heater 25, a temperature sensor 20, and a specific gas absorbing material 5, and acts as a detection sensor, and the other thin film 11 has a heater 26, a temperature sensor 21, and a specific gas.
- a balance film 6 is formed in place of the absorbing material 5 and is adjusted so as to have substantially the same thermal time constant ⁇ in an atmospheric gas without a specific gas, and is operated as a reference sensor.
- palladium (Pd) which is a hydrogen absorbing material 5 is formed.
- oxygen gas is detected, disulfide of the layered crystal thin film which is the oxygen gas absorbing material 5 is formed.
- a titanium thin film is formed.
- a thin film of the absorbing material 5 having good selectivity with respect to the specific gas is formed, for example, by using an intercalation effect.
- the heater 25 and the heater 26 are examples in which the temperature sensor 20 and the temperature sensor 21 are heater / temperature sensors, respectively. So that the temperature can be raised. Thereafter, in the cooling process after the heater heating is stopped, the original operation as a temperature sensor is used.
- the temperature sensors 20 and 21 may be absolute temperature sensors such as platinum resistors or pn junction diodes, but here, a temperature difference sensor is used as the thermocouple 120 that can use the zero-position method as it is. Hydrogen gas concentration can be measured.
- These thermocouples 120 are formed using the n-type SOI layer 12 as the thermocouple conductor 120a and a metal film such as nichrome formed via the silicon oxide film 51 thereon as the thermocouple conductor 120b. Yes.
- the electrode pads 70, 71, 72 is provided. Further, in this example, the absolute temperature sensor 23 is provided on the substrate in order to measure the temperature of the substrate 1 which is the reference temperature.
- the absolute temperature sensor 23 is a pn junction diode.
- the specific gas concentration sensor when hydrogen gas is used as the specific gas will be described as follows.
- the thermal time constant ⁇ of the cantilever-like thin film 10 and the thin film 11 is 5 milliseconds (mSec).
- the thermocouple 120 has a resistance value of about 30 ⁇ and is heated to about 200 ° C. with a heating power of about 100 milliwatts.
- the thin film 10 and the thin film 11 are simultaneously heated in an atmospheric gas containing hydrogen gas (H 2 gas), for example, in air.
- H 2 gas hydrogen gas
- a voltage is applied between the common electrode pad 72 and the electrode pads 70 and 71 of the respective SOI layers 12 for the terminals at this time, and the temperature sensors 20 and 21 are operated as heaters, so that the temperature is about 150 ° C.
- the hydrogen absorbed in the hydrogen absorbing material 5 is released.
- the heating application voltage is set to zero, the heater heating is stopped, and the voltage between the electrode pad 70 and the electrode pad 71 is measured, whereby the output voltage difference between the temperature sensor 20 and the temperature sensor 21 is differentially determined. Measure with an amplifier circuit. Originally, if the thin film 10 and the thin film 11 are completely equivalent both thermally and electrically, the voltage between the electrode pad 70 and the electrode pad 71 should always be zero when there is no hydrogen gas. Actually, there is a slight deviation and it is not completely zero. After the heating is stopped, the output voltage (voltage between the electrode pads 71 and 72) of the thin film 11 not having the hydrogen absorbing material 5 becomes zero at a time point of about 4 to 5 times the thermal time constant ⁇ . No.
- the 10 has a hydrogen absorbing material 5, and therefore, due to an exothermic reaction based on the absorption of hydrogen gas during cooling, a temperature increase due to the exothermic reaction is observed until the absorption is completely completed.
- the output voltage between the electrode pads 70 and 71 is observed. This value is observed as a monotonous function in the low hydrogen gas concentration range up to the above-mentioned peak hydrogen gas concentration, and the hydrogen gas in the atmospheric gas prepared at a specific time after the heating stop prepared in advance.
- the hydrogen gas concentration can be obtained using the relationship data (calibration data) between the concentration and the output voltage.
- the output voltage between the electrode pads 70 and 71 is essentially zero at a time point about 4 to 5 times the thermal time constant ⁇ after heating is stopped. Therefore, since the zero position method can be applied, it is particularly suitable for hydrogen gas concentration measurement in a low hydrogen gas concentration region.
- the thin film 10 and the thin film 11 are differentially operated.
- the thin film 11 as the reference sensor is not necessarily provided. Is unnecessary.
- the thin film 10 having the hydrogen absorbing material 5 is heated with a predetermined power, and after releasing hydrogen, it is several times (for example, 4 times) the thermal time constant ⁇ after the heating is stopped.
- the output voltage between the electrode pad 70 and the electrode pad 72 may be measured using the terminal voltage of the temperature sensor 20 which is a temperature difference sensor provided in the thin film 10.
- the output voltage is essentially zero, so the zero position method is applied as it is, and a highly accurate specific gas concentration sensor is obtained.
- the thin film 10 and the thin film 11 are heated at the same time, and the ultimate temperature immediately after the heating is stopped is measured by measuring the output voltage between the electrode pad 71 and the electrode pad 72.
- the relationship data between the hydrogen gas concentration at this time and the temperature reached when heated at a predetermined power is acquired in advance and treated as a heat conduction type hydrogen sensor. It is advisable to obtain a wide range of hydrogen gas concentrations in the gas.
- the heating time there is a rise in temperature due to the release of hydrogen gas from the absorbing material 5 and catalytic combustion.
- This heating period is also set as a predetermined time, and under that, the hydrogen gas concentration and the predetermined power are used. It is necessary to obtain in advance the relationship data (calibration data) with the temperature reached when heated. If the heating time is several times the thermal time constant ⁇ , for example, 4 to 5 times, stable and reproducible data can be obtained. Further, the output information of the temperature rise based on the combustion of the hydrogen gas when heated can also be used as confirmation information in the concentration region higher or lower than the peak hydrogen gas concentration of the hydrogen gas.
- thermocouple 120 is used as the temperature sensors 20 and 21 and the heater 25, the ohmic contact is obtained to obtain a good ohmic contact by a known semiconductor microfabrication technique.
- N-type thermal diffusion regions are preferably formed at the locations of the conductive electrodes 60a, 60b, 61a, 61b.
- a pn junction diode is formed as the absolute temperature sensor 23 provided on the substrate 1, it can be easily formed by a known diffusion technique.
- thermocouple conductor 120b of the thermocouple 120 since differential amplification is performed, it is necessary to use the same metal. Nichrome and nickel (Ni) based metals are suitable because they are resistant to strong alkaline etchants. When not exposed to a strong alkali-based etchant by dry etching or the like, an ohmic electrode or wiring 110 and an electrode pad are preferably formed by using an aluminum (Al) -based metal and forming the sputtering thin film and photolithography. There is a dedicated etchant for patterning the Pd hydrogen absorbing material 5, and dry etching is performed as necessary.
- the cavity 40 formed in the substrate 1 can be formed from the back surface by an etchant or DRIE, and the slit 41 from the front surface side is similarly formed and penetrated.
- the electrode pad 70 and the electrode pad 71 serving as terminals on the n-type SOI layer 12 side serving as cold junctions on the substrate side of the thermocouple 120 formed in the thin film 10 and the thin film 11 are the same n-type SOI layer 12.
- the islands are left by the grooves 130 reaching the BOX layer 13 and are electrically separated.
- the details of the first embodiment described above were when hydrogen gas was used as the specific gas.
- oxygen gas was used as the specific gas
- the titanium disulfide thin film which is a layered crystal, is formed to a thickness of about 1 ⁇ m.
- a titanium disulfide layered crystal thin film for example, in hydrogen sulfide for the purpose of suppressing the evaporation of sulfur (S) after forming a known CVD (chemical vapor deposition), sol-gel method or sputtering thin film.
- the oxygen gas concentration can be measured by measuring the temperature rise of the output voltage difference between the temperature sensor 20 and the temperature sensor 21 of the thermocouple 120, which is a temperature difference sensor.
- FIG. 3 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 characteristic of the specific gas concentration sensor of the present invention
- FIG. 4 is a schematic cross-sectional view taken along the line XX.
- the thin film 10 made into the structure floating in the air for the thermal separation from the board
- the thin film 10a as the thin film and the thin film 10b as the other thin film are divided into two, and the thin film 10a and the thin film 10b having the same shape protrude from the thin film 10 into a cantilever shape.
- the specific gas absorbing material 5 is formed on 10a, and the thin film 10b is formed with a balance film 6 that is inert to the specific gas instead of the specific gas absorbing material 5, and has an equivalent thermal time constant ⁇ .
- the temperature sensors 20 and 21 are thermocouples 120 which are temperature difference sensors.
- the heater 25 is formed of a nichrome thin film or the like in the common region 15 corresponding to the branching base in order to heat the thin film 10a and the thin film 10b equally. Therefore, the heater 25 and the temperature sensor are independent and electrically separated, so that heating and temperature measurement can always be performed.
- the heater 25 and the thermocouple 120 cannot be operated independently in time.
- the shape is somewhat larger, but it is suitable for purposes such as temperature measurement during heating.
- the thin film 10a is operated as a detection sensor and the thin film 10b is operated as a reference sensor as in the first embodiment.
- the temperature sensors 20 and 21 mounted on these thin films are thermocouples 120 that are temperature difference sensors.
- the feature here is that the common cold junction of the temperature sensors 20 and 21 is provided in the common region 15 where the heater 25 is arranged in the base region where the thin film 10 branches from the thin film 10a and the thin film 10b.
- the ohmic electrode 62b is provided on the n-type SOI layer 12 as the counter conductor 120a.
- the temperature difference between the thin film 10a and the thin film 10b generated according to the hydrogen gas concentration can be measured as the output difference between the temperature sensors 20 and 21, which is the same as that shown in the first embodiment.
- the differential output after a thermal time constant ⁇ several times after stopping the heating, it is possible to obtain a highly accurate specific gas concentration to which the zero method is applied.
- the heater 25 is formed independently of the temperature sensors 20 and 21, when the specific gas is hydrogen gas, there is an advantage that it is easy to obtain information such as a temperature rise based on the combustion of the hydrogen gas during heating. .
- the temperature sensor 21 mounted on the thin film 10b can be heated and used as a heater, and a wide range of hydrogen gas concentrations can be measured as a heat conduction type sensor. Even in this case, it is necessary to check whether the change in the heat conduction type sensor is caused by hydrogen or not as information on the temperature change caused by the hydrogen gas in the thin film 10a on which the hydrogen absorbing material 5 is mounted.
- the manufacturing process of the specific gas concentration sensor element 100 shown in FIGS. 1 and 2 is the same as the manufacturing process of the specific gas concentration sensor element 100 according to the first embodiment by a known MEMS technique, and thus the description thereof is omitted here.
- FIG. 5 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 characteristic of the specific gas concentration sensor of the present invention
- FIG. 6 is a schematic cross-sectional view along the line XX.
- the major difference from the specific gas concentration sensor element 100 shown in FIGS. 1 and 2 of the first embodiment is that the thin films 10 and 11 have a cantilever structure in FIGS. 1 and 2, whereas FIGS. Then, it is the point comprised by the bridge
- thermocouple temperature sensors 20 and 21 are used as the original temperature difference sensor, and the other one thermocouple 120 is used as the heaters 25 and 26.
- the specific gas is hydrogen gas
- the temperature rise is small even if the heat generation due to hydrogen absorption is the same, but the response speed increases.
- the thin films 10 and 11 become stronger in strength, and the cantilever also has an advantage that the complicated wiring 110 is supported at both ends by the bridging structure 3 and can be easily pulled out to the substrate 1 side.
- the heaters 25 and 26 and the temperature sensors 20 and 21 are formed on the thin films 10 and 11, respectively, it is easy to measure the temperature during heating, and when the specific gas is hydrogen gas, Temperature control such as raising the reference temperature of the information during combustion and the temperature of the thin films 10 and 11 slightly from room temperature becomes easier.
- the thin film 10 loaded with the absorbing substance 5 of the specific gas is operated as a sensor for detection, and the thin film 11 is operated as a sensor for reference, and the measurement method of the specific gas is the same as in the case of the first embodiment. The description is omitted here.
- FIG. 7 is a schematic plan view showing another embodiment of the specific gas concentration sensor element 100 characteristic of the specific gas concentration sensor of the present invention.
- the thin film 10 and the thin film 11 have the cross-linking structure 3, in order to obtain a large temperature rise even with a slight heat generation, it is preferable that the length of the beam 18 of the cross-linking structure 3 is long.
- the orientation of the crystal is important for performing three-dimensional processing such as forming a cavity 40 with an etchant in the substrate 1 using the MEMS technique.
- the crystal orientation is used to form a high-precision cavity 40, such as applying an etch stop, utilizing the fact that the etching rate of the (111) plane of the crystal is extremely slower than other orientations. It is.
- the crystalline silicon is etched in as short a time as possible in consideration of the angle and the width with respect to the crystal orientation of the beam 18 of the bridge structure 3. Thus, it is necessary to form the beam 18 having the long bridge structure 3.
- the beam 18 of the long bridge structure 3 has an angle of 45 degrees with respect to the length direction of the cavity 40 in the (110) direction with respect to the surface of the (100) crystal plane of the substrate 1. It can also be considered that the beam 18 of the bridging structure 3 is formed like a cantilever as a whole with respect to both end support portions.
- the hydrogen absorbing material 5 is provided in a region that is also the tip of the cantilever and the central portion of the beam 18 of the cross-linking structure 3. Is provided with a balance film 6 made of inert nichrome or chromium.
- the temperature sensors 20 and 21 also use the thermocouple 20 which is a temperature difference sensor in this case, and the heater 25 can also be used.
- thermocouples 120 are composed of the n-type SOI layer 12 as the thermocouple conductor 120a and nichrome as the thermocouple conductor 120b.
- the terminals of the n-type SOI layer 12 as the thermocouple conductor 120a are shared by the temperature sensors 20 and 21, and the electrode pads 70 and 71 through the ohmic electrodes 60a and 61a at the same location correspond to this.
- the voltage between the electrode pad 70 and the electrode pad 72a may be measured, and the reference sensor In order to measure the temperature rise of the thin film 11 that does not have the specific gas absorbing material 5, the voltage between the electrode pad 71 and the electrode pad 72 b may be measured. In order to measure the temperature difference between the thin film 10 and the thin film 11, the voltage between the electrode pad 72a and the electrode pad 72b may be measured.
- the specific gas concentration measurement is almost the same as in the above-described embodiment.
- the absolute temperature sensor 23 for knowing the absolute temperature of the substrate 1 is omitted.
- FIG. 8 is a schematic cross-sectional view showing another embodiment of the specific gas concentration sensor element 100 characteristic of the specific gas concentration sensor of the present invention.
- the thin film 10 and the thin film 11 provided in the specific gas concentration sensor element 100 are three-dimensionally processed from the substrate 1 such as silicon so as to have the cavity 40 in the lower portion, and from the substrate 1. It was thermally separated.
- a sacrificial layer etching technique known in the MEMS technology is used, and a sacrificial layer film (not shown here; embedded in the cavity 40 but etched away when the cavity is formed).
- a thin film to be a cantilever or a beam 18 of the cross-linking structure 3 is formed over the top, and then the sacrificial layer is removed by etching to create a cavity 40 on the substrate 1. These are formed in the shape of the cantilever 7 or the bridge structure 3 to achieve thermal separation from the substrate 1.
- various IC electronic circuits for operating as a specific gas concentration sensor on the substrate 1 corresponding to the lower portion thereof for example, OP
- An amplifier, various amplifier circuits, a drive circuit for the heaters 25 and 26, an arithmetic circuit, a memory circuit, a control circuit, a display circuit, and the like are created in advance, and then the thin film 10 and the thin film 11 are formed. If it does in this way, the shape of a specific gas concentration sensor element becomes compact, and the specific gas concentration sensor which integrated the electronic circuit can be provided.
- the main body of the thin film 10 or the thin film 11 is made of polysilicon, the heaters 25 and 26, the thermocouple 120, etc.
- the thin film 10 and the thin film 11 are formed of an n-type low-resistance polysilicon thin film.
- the cavity 40 is formed, and the anchor portion 360 forms the silicon single crystal substrate 1. It shows a state in which the structure is thermally separated from the self-supporting substrate 1.
- the specific gas absorbing material 5 may be formed of, for example, palladium Pd for hydrogen gas and titanium disulfide for oxygen gas, and may be formed in the same manner as in the above-described embodiments by sputtering or the like. The operation is also the same as in the above-described embodiment using the thin film 10 and the thin film 11 formed by processing the substrate 1 itself.
- the shape of the above-mentioned specific gas concentration sensor element has been mainly shown in the case of hydrogen gas as the specific gas.
- the hydrogen gas sensor is known to have a peak hydrogen gas concentration or less that utilizes the absorption (occlusion) heat generation effect of hydrogen, as described above, the thin film 11 serving as the reference sensor in FIG.
- the specific gas is, for example, oxygen gas
- the exothermic action based on the intercalation of titanium disulfide, which is an oxygen absorbing material 5 is monotonously increased for an oxygen concentration of 0 to 100%. Therefore, the thin film 11 which is the reference sensor in FIG. 1 is unnecessary.
- FIG. 9 shows a simple structure in which the thin film 11 of the reference sensor in FIG. 1 is removed.
- a layered crystal thin film of titanium disulfide is formed on the thin film 10 of the detection sensor 8 as the oxygen absorbing material 5, and oxygen is intercalated into the oxygen absorbing material 5.
- a temperature rise amount with respect to the substrate 1 based on the absorption heat generation effect when absorbed by the calation is measured.
- the absorption of oxygen depends on the temperature of the absorbing material 5, and if the temperature is high, the amount of absorption is small and the amount of heat generated is small, and if it is sufficiently absorbed and not absorbed any more, the heat generation stops and the ambient temperature is room temperature. Go back.
- substrate 1 at this time can be measured using the thermocouple 120 which is the temperature sensor 20 as a temperature difference sensor.
- the detection sensor 8 is heated by the heater 25 (in this case, the thermocouple 120 and the heater 25 are also used), and the oxygen gas absorbed so far During the cooling process after heating is stopped and the temperature rises from the substrate 1 at a specific time (several times the thermal time constant ⁇ of the cantilever 7 of the original detection sensor 8) or more The oxygen concentration is measured by measuring the minutes with the thermocouple 120.
- the oxygen concentration can be measured based on this equilibrium state. That is, in the air, nitrogen gas and oxygen gas are present in a ratio of 4: 1.
- the absorbing material 5 begins to absorb oxygen and generates heat, but eventually returns to room temperature, so that it becomes in a thermal equilibrium state with the oxygen concentration in the air and the heat generation stops. This calorific value is different from that when calibrated with a gas having no surrounding oxygen.
- calibrating the absolute oxygen gas concentration it is necessary to obtain and prepare calibration characteristic data in advance.For example, calibration data using a standard gas having an oxygen absolute concentration in pure nitrogen gas is required. It is good to have it ready.
- the specific gas concentration sensor element 100 that is characteristic of the specific gas concentration sensor of the present invention is covered with a cap having a mesh structure, thereby blocking the air flow and preventing explosion against flammable gases such as hydrogen gas.
- the specific gas concentration sensor element 100 is bonded to an element holder 500 made of an alumina substrate or a flame-retardant plastic substrate, and an electrically insulating lead holder 350 having leads 300 is bonded to electrically connect the lead
- the lead 300 and each electrode pad of the specific gas concentration sensor element 100 are joined via 310.
- power supply and input / output of electric signals are performed between the outside and the specific gas concentration sensor element 100 through the lead 300.
- the cap 200 having a mesh structure is joined so that the porous mesh structure 210 is located near the cavity 40 where the thin film 10 and the thin film 11 of the specific gas concentration sensor element 100 are provided.
- the element holder 500 is also provided with the mesh structure portion 210 as necessary.
- the element holder 500 is also provided with a mesh structure 210.
- FIG. 11 is a block diagram showing another embodiment of the specific gas concentration sensor of the present invention, in which a specific gas concentration sensor package incorporating a characteristic specific gas concentration sensor element 100 and an electronic circuit are integrated. This is a case where it is modularized. In this embodiment, a heater drive circuit, an amplifier circuit, and an arithmetic circuit are used as electronic circuits. Here, it is a case where a power source is obtained from the outside, and an output signal terminal that can take out a signal related to the specific gas concentration to the outside is also provided.
- FIG. 12 is a block diagram showing another embodiment of the specific gas concentration sensor of the present invention.
- the specific gas concentration sensor package and the electronic circuit shown in Embodiment 7 are integrated and modularized.
- the gas concentration sensor is a specific gas concentration sensor that can be provided as a specific gas concentration meter, and includes a power supply circuit, a control circuit, and a display circuit that can display a hydrogen gas concentration, etc. Furthermore, this is a case where an output signal terminal that can output a signal of a specific gas concentration is provided outside.
- the specific gas concentration meter becomes a hydrogen gas concentration meter if hydrogen gas is targeted as the specific gas, and becomes an oxygen gas concentration meter if oxygen gas is targeted as the specific gas.
- the specific gas concentration sensor element is obtained when the n-type SOI layer 12 is used.
- a similar sensor can be achieved even when the p-type SOI layer 12 is used.
- the specific gas concentration sensor of the present invention is not limited to the present embodiment, and various modifications can naturally be made while the gist, operation and effect of the present invention are the same.
- the specific gas concentration sensor of the present invention is for measuring the concentration of a specific gas in an atmospheric gas and the temperature rise in an exothermic reaction due to absorption of the specific gas by the absorbing material 5 with high sensitivity and high accuracy. It is a thermal sensor.
- the specific gas concentration sensor of the present invention when the specific gas concentration sensor of the present invention is applied to measure the concentration of a specific gas in the atmosphere, an ultra-compact thermoelectric device that detects only a temperature difference with high sensitivity and high accuracy in a thin film floating in the air. If a pair is used, the zero method can be applied.
- the specific gas is hydrogen gas
- the hydrogen gas concentration can be measured with extremely high accuracy at a hydrogen concentration of 4% or less of the explosion limit in air.
- the specific gas is oxygen gas
- the oxygen gas is almost close to the thermal conductivity of air, so the calorific value increases monotonously with respect to the oxygen concentration.
- An oxygen gas concentration of 0 to 100% can be measured.
- hydrogen gas since hydrogen gas is the gas with the highest thermal conductivity, the effect of high thermal conductivity of hydrogen gas above a specific hydrogen concentration (hydrogen concentration with temperature rise due to absorption heat generation) (Having a peak at about 5%) surface. Therefore, it is different from the detection mechanism based on the absorption heat of hydrogen, such as using a reference sensor that does not have the hydrogen absorbing material 5 or using a reference sensor in which the surface of the absorbing material 5 is deactivated. It is possible to measure a hydrogen gas concentration of 0 to 100% by using the operation as a thermal conductivity sensor that utilizes the fact that the thermal conductivity increases as the amount of hydrogen gas in the hydrogen gas atmosphere increases. it can.
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Abstract
Description
3 架橋構造
5 吸収物質
6 バランス膜
7 カンチレバ
8 検出用センサ
9 参照用センサ
10、10a、10b 薄膜
11 薄膜
12 SOI層
13 BOX層
15 共通領域
18 梁
20、21 温度センサ
23 絶対温度センサ
25、26 ヒータ
40 空洞
41 スリット
50 電気絶縁膜
51 シリコン酸化膜
60、60a、60b オーム性電極
61a、61b オーム性電極
62a、62b オーム性電極
70,71,71a、71b 電極パッド
72, 72a、72b 電極パッド
73a、73b 電極パッド
74、74a、74b 電極パッド
100 特定ガス濃度センサ素子
110 配線
120 熱電対
120a, 120b 熱電対導体
130 溝
200 キャップ
210 メッシュ構造部
300 リード
310 リード接合部
350 リードホルダ
360 アンカー部
400 空隙
500 素子ホルダ
600 IC化電子回路
Claims (18)
- 基板(1)から熱分離した薄膜(10)に、ヒータ(25)と温度センサ(20)および特定ガスの吸収物質(5)とを備え、雰囲気ガス中の該特定ガスの吸収時の発熱に伴う温度変化を前記温度センサ(20)により計測できるようにした特定ガス濃度センサにおいて、吸収されている特定ガスを前記ヒータ(25)の加熱により吸収物質(5)から放出させ、前記ヒータの加熱を停止させた後、前記ヒータ(25)の特定ガスが存在していないときの前記薄膜(10)の熱時定数τ以上の所定の時間経過時点での前記温度センサ(20)の出力を利用し、その雰囲気ガス中での前記特定ガス濃度を求めるようにしたことを特徴とする特定ガス濃度センサ。
- 前記特定ガスとして水素ガスとした請求項1に記載の特定ガス濃度センサ。
- 水素の吸収物質(5)として、化学的に安定な金属である白金(Pt)またはパラジウム(Pd)を含む物質とした請求項2に記載の特定ガス濃度センサ。
- 水素の吸収物質(5)と物理的もしくは化学的に反応する水素とは異なるガスが吸収物質(5)と直接接触し難いように、吸収物質(5)を保護膜で被服した請求項2もしくは3のいずれかに記載の特定ガス濃度センサ。
- 前記ヒータ(25)を所定の電力、電圧もしくは電流で加熱し、停止させた後、冷却過程での前記薄膜(10)の熱時定数τ以上の所定の時間経過時点で、前記温度センサ(20)の温度を計測するものであって、ピーク水素ガス濃度以下での水素ガス濃度範囲において、水素ガス濃度を求めるようにした請求項2から4のいずれかに記載の特定ガス濃度センサ。
- 基板(1)から熱分離した薄膜(11)に、ヒータ(26)と温度センサ(21)とを備えるが、水素の吸収物質(5)は備えないか、もしくは備えても不活性になるようにしてあり、前記ヒータ(26)を所定の電力、電圧もしくは電流の下で加熱し、前記ヒータ(26)の加熱中の温度、もしくは加熱中止直後からの所定の時間経過時における冷却時の温度計測、または、所定の温度になるまでの経過時間の計測を、前記温度センサ(21)を用いて行うようにし、雰囲気ガス中の水素ガス濃度による熱伝導率の違いに基づく前記温度センサ(21)の出力または出力の変化を利用して、少なくとも3%以上で100%までの水素ガスの濃度も計測できるようにした熱伝導型センサとしての水素ガスセンサを備えた請求項2から5のいずれかに記載の特定ガス濃度センサ。
- 雰囲気ガス中の水素ガス濃度の大まかな範囲を推定するのに、前記ヒータ(25)を所定の電力、電圧もしくは電流の下で加熱し、前記ヒータ(25)の加熱中の水素の燃焼に基づく前記温度センサ(20)の出力情報も利用できるようにした請求項2から6のいずれかに記載の特定ガス濃度センサ。
- 前記特定ガスとして酸素ガスとした請求項1に記載の特定ガス濃度センサ。
- 酸素の吸収物質(5)として、層状物質を含み、該層状物質での酸素のインターカレーション反応に伴う発熱反応を利用した請求項8に記載の特定ガス濃度センサ。
- 前記薄膜(10)を少なくとも二つの薄膜(10a)と薄膜(10b)に分割してあり、これらの薄膜(10a)と薄膜(10b)の分割の根元付近の共通領域に、薄膜(10a)と薄膜(10b)とを同等に加熱できるヒータ(25)を設けてあり、薄膜(10a)には、温度センサ(20)と特定ガスの吸収物質(5)を備え、薄膜(10b)には、温度センサ(21)を備えるが、特定ガスの吸収物質(5)は備えないか、備えても不活性になるようにしてあり、薄膜(10a)を特定ガスの検出用センサとし、薄膜(10b)を参照用センサとして取り扱い、薄膜(10a)と薄膜(10b)との温度差を検出できるようにしてあり、この温度差の出力情報を利用できるようにした請求項1から9のいずれかに記載の特定ガス濃度センサ。
- 前記薄膜(10a)と前記薄膜(10b)とは、略同一の形状となし、必要に応じて、前記薄膜(10b)には、薄膜(10a)に形成してある特定ガスの吸収物質(5)と同等の熱容量の物質をバランス膜(6)として形成した請求項10記載の特定ガス濃度センサ。
- 薄膜(11)を、前記薄膜(10)とは別に基板(1)から熱分離して形成し、前記薄膜(10)とは、特定ガスの吸収物質(5)を有しないが同等の形状とした請求項1から9のいずれかに記載の特定ガス濃度センサ。
- 前記温度センサ(20、21)として、温度差センサとした請求項1から12のいずれかに記載の特定ガス濃度センサ。
- 前記温度センサ(20、21)に電流を流して前記ヒータ(25、26)としても利用するようにした請求項1から13のいずれかに記載の特定ガス濃度センサ。
- 前記基板に、雰囲気ガスの温度計測用として絶対温度センサを設けた請求項1から14のいずれかに記載の特定ガス濃度センサ。
- 基板(1)を半導体基板とし、該基板(1)の上方に重ねて形成した犠牲層を介して形成した薄膜(10)や薄膜(11)を形成してあり、犠牲層をエッチング除去して空洞を形成してあり、必要に応じて、前記基板(1)に電子回路を形成できるようにした請求項1から15のいずれかに記載の特定ガス濃度センサ。
- 特定ガス濃度センサ素子を、メッシュ構造を有するキャップで覆うことにより、気流を遮り、必要に応じて防爆型とした請求項1から16のいずれかに記載の特定ガス濃度センサ。
- 前記ヒータ(25、26)を所定のサイクルで加熱できるように、少なくとも電子回路を備え、雰囲気ガス中の特定ガス濃度を計測し、その出力を外部に取り出せるようにした請求項1から17のいずれかに記載の特定ガス濃度センサ。
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---|---|---|---|---|
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0534307A (ja) * | 1991-08-02 | 1993-02-09 | Fujikura Ltd | 酸素センサ |
JP2008111822A (ja) * | 2006-10-04 | 2008-05-15 | Mitsuteru Kimura | ガスセンサ素子およびこれを用いたガス濃度測定装置 |
JP2009128254A (ja) * | 2007-11-26 | 2009-06-11 | Mitsuteru Kimura | 不純物濃度センサ、フローセンサおよびこれらを用いた計測・制御システム |
-
2011
- 2011-09-08 US US13/821,805 patent/US9261472B2/en not_active Expired - Fee Related
- 2011-09-08 WO PCT/JP2011/070427 patent/WO2012033147A1/ja active Application Filing
- 2011-09-08 JP JP2012533014A patent/JP5888747B2/ja not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0534307A (ja) * | 1991-08-02 | 1993-02-09 | Fujikura Ltd | 酸素センサ |
JP2008111822A (ja) * | 2006-10-04 | 2008-05-15 | Mitsuteru Kimura | ガスセンサ素子およびこれを用いたガス濃度測定装置 |
JP2009128254A (ja) * | 2007-11-26 | 2009-06-11 | Mitsuteru Kimura | 不純物濃度センサ、フローセンサおよびこれらを用いた計測・制御システム |
Non-Patent Citations (2)
Title |
---|
NORIAKI TAKASHIMA ET AL.: "Palladium no Suiso Kyuzo ni yoru Hatsunetsu o Riyo shita Suiso Gas Sensor no Teian", HEISEI 22 NEN NATIONAL CONVENTION RECORD I.E.E., 5 March 2010 (2010-03-05), JAPAN, pages 231 * |
YASUHIRO ABE ET AL.: "Development of a MEMS Gas Flow Sensor Unified with an Impurity-Gas Concentration Sensor", THE TRANSACTIONS OF THE INSTITUTE OF ELECTRICAL ENGINEERS OF JAPAN E, vol. 130, no. 8, 1 August 2010 (2010-08-01), pages 412 - 416 * |
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