JP4340639B2 - Hydrogen sensor and hydrogen detection method - Google Patents

Description

  The present invention relates to a hydrogen sensor and a hydrogen detection method, and more particularly to a material of a hydrogen absorber attached on a semiconductor.

  Conventionally, various hydrogen gas detections have been made in which a layer made of palladium is formed as a hydrogen absorber or as a catalyst layer that catalyzes the hydrogen absorption reaction to the sensitive body on a semiconductor made of a semiconductor and chemically reacts with hydrogen. Elements have been proposed (see, for example, Patent Document 1 and Patent Document 2).

That is, Patent Document 1 discloses an insulating substrate, a gas sensitive body made of a metal oxide semiconductor such as SnO ₂ or In ₂ O ₃ provided on the insulating substrate, and 1 provided on the gas sensitive body. A hydrogen gas detection element is described that includes a catalyst layer made of a pair of electrodes and palladium, and a heating element disposed on the back side of the insulating substrate. This hydrogen gas detection element is intended to improve sensitivity to hydrogen gas and decrease sensitivity to gases other than hydrogen gas by performing heat treatment in the final step of element formation.

Further, Patent Document 1 discloses a combustion-inactive thin film that suppresses the passage of molecules other than hydrogen gas to the surface of a gas sensitive body and easily allows hydrogen gas molecules to pass therethrough, such as Al ₂ O ₃ , SiO ₂ , Si _3. A hydrogen gas sensing element in which a thin film such as N ₄ is formed is also described. Since this hydrogen gas detection element can selectively permeate hydrogen gas to the surface of the gas sensing element by the thin film, interference by gases other than hydrogen gas can be reduced, and the sensitivity of the hydrogen gas detection element can be reduced. Can be increased.

On the other hand, Patent Document 2 includes an insulating substrate, a thin-film gas sensitive body made of In ₂ O ₃ provided on the insulating substrate, and a pair of electrodes and palladium provided on the gas sensitive material. There is described a hydrogen gas detection element including a catalyst layer, a partial poisoning agent made of Si oxide applied to the surface of the catalyst layer, and a heating element arranged on the back side of the insulating substrate. In this hydrogen gas detection element, a partial poisoning made of Si oxide is applied to the surface of the catalyst layer, and hydrogen gas is selectively absorbed by the catalyst layer, so that interference by gases other than hydrogen gas is reduced. And the sensitivity of the hydrogen gas sensing element can be increased.
Japanese Patent Laid-Open No. 3-259736 JP-A-6-148112

  However, since the hydrogen absorption capacity of palladium reaches a nearly saturated state at a low hydrogen concentration of about 0.3%, a hydrogen gas detection element equipped with palladium as a hydrogen absorber or catalyst layer has a hydrogen absorption capacity of 0.3% or more. The concentration cannot be measured accurately. For this reason, the conventional hydrogen gas detection element is effective as a sensor for detecting the presence or absence of low-concentration hydrogen gas, but can detect hydrogen up to a higher concentration range stepwise or continuously. It was difficult.

  The present invention has been made to solve such deficiencies in the prior art, and its purpose is to increase the hydrogen concentration at which the hydrogen absorption capacity of the hydrogen absorber is saturated, thereby reducing the hydrogen gas concentration in the atmosphere. An object of the present invention is to provide a hydrogen sensor capable of detecting stepwise or continuously up to a higher concentration range than in the past.

  In order to solve the above-mentioned problems, the present invention relates to a hydrogen sensor, a semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium containing gold as a main component, and the hydrogen absorption. A configuration is provided in which at least one pair of electrodes arranged at a position not conducting with the hydrogen absorber on the semiconductor is provided across the attachment position of the body.

  According to experiments, gold also has a hydrogen absorption capacity, and the hydrogen absorption capacity of gold does not reach saturation until a concentration of about 2.0%. Therefore, the hydrogen sensor provided with the hydrogen absorber made of gold can expand the detection range of the hydrogen gas concentration as compared with the case where the hydrogen absorber made of palladium is used, and the level of the hydrogen gas concentration in the atmosphere. Or continuous detection is possible. An alloy of gold and palladium also has a hydrogen absorption capability, and when the palladium composition ratio in the alloy is suppressed to about 10%, the hydrogen absorption capability does not reach a saturation state to a concentration of about 2.0%. . Therefore, in the same manner as a hydrogen sensor having a hydrogen absorber made of gold, a hydrogen sensor having a hydrogen absorber made of an alloy of gold and palladium can be compared with a case where a hydrogen absorber made of palladium is used. The detection range of the gas concentration can be expanded, and stepwise or continuous detection of the hydrogen gas concentration in the atmosphere becomes possible. In addition, since an electrode is generally formed with gold | metal | money, when a hydrogen absorber is formed with gold | metal | money, the manufacturing process of a hydrogen sensor can be simplified and the cost reduction of a hydrogen sensor can be achieved.

  According to the present invention, in the hydrogen sensor having the above configuration, a semiconductor formed in a layered manner on an insulating substrate is used as the semiconductor.

  A layered semiconductor can be easily formed with a required film thickness over an insulating substrate by applying a vacuum film formation method such as vacuum evaporation or sputtering. Therefore, if the semiconductor is a layered semiconductor provided over an insulating substrate, the manufacture of the hydrogen sensor can be facilitated, the cost of the hydrogen sensor can be reduced, and the size of the hydrogen sensor can be reduced.

Further, according to the present invention, in the hydrogen sensor having the above configuration, a non-oxide semiconductor is used as the semiconductor. The semiconductor non-oxide, silicon, silicon carbide, germanium, silicon germanium, gallium arsenide, gallium nitride, can be used as a main component one of the carbon-containing.

  Hydrogen sensors using oxide-based semiconductors, when reducing gas (combustible gas) acts on the semiconductor material, the reducing gas exerts the action of stripping oxygen from the oxide semiconductor material and traps in oxygen The basic principle is that the electron depletion layer is thinned by the remaining electrons in the semiconductor, the region where charge carriers are present increases, and the resistance value changes. Therefore, in principle, hydrogen sensors using oxide-based semiconductors always react with reducing gases such as methane gas, propane gas, and ethyl alcohol other than hydrogen gas, which improves the selectivity of hydrogen gas. Even if various means are applied, only hydrogen gas cannot actually be detected. In addition, since the hydrogen sensor of this structure uses a reduction reaction between an oxide semiconductor material and a reducing gas, the sensitivity tends to be good at a high temperature of 200 to 300 ° C., and the hydrogen sensor has a heating element such as a heater. It is necessary to have. In contrast, a hydrogen sensor using a non-oxide semiconductor has resistance due to the influence of electron mobility inside the semiconductor by another resistance value fluctuation mechanism that is not caused by oxidation or reduction reaction. Since the value is changed, only hydrogen gas can be detected without reacting with reducing gas other than hydrogen gas. In addition, hydrogen gas can be detected at room temperature and there is no need to provide a heating element such as a heater, so the hydrogen sensor can be downsized, power consumption can be reduced, output stability can be improved, and sensor durability can be improved. Etc.

  According to the present invention, in the hydrogen sensor having the above-described configuration, the hydrogen absorber is formed directly on the semiconductor.

  When the hydrogen absorber is formed in direct contact with the surface of the semiconductor in this way, the influence of the hydrogen absorbed by the hydrogen absorber can be directly exerted on the semiconductor, so that the output change corresponding to the hydrogen concentration can be reliably detected. be able to.

  According to the present invention, in the hydrogen sensor having the above-described configuration, a thin film insulating layer is interposed between the semiconductor and the hydrogen absorber.

  When the hydrogen absorber is formed on the semiconductor through the thin film insulating layer in this way, the surface of the semiconductor is protected by the thin film insulating layer, so that the durability and reliability of the hydrogen sensor can be improved. Even when a hydrogen absorber is formed on a semiconductor through a thin film insulating layer, the hydrogen absorber that has absorbed hydrogen affects the semiconductor through the thin film insulating layer and changes the resistance value of the semiconductor.

  According to the present invention, in the hydrogen sensor having the above-described configuration, the exposed surface of the hydrogen absorber is covered with a hydrogen-permeable protective film.

  If the exposed surface of the hydrogen absorber is covered with a hydrogen-permeable protective film in this manner, hydrogen in the atmosphere can selectively reach the hydrogen absorber, and thus the sensitivity of the hydrogen sensor can be increased. Moreover, since the exposed surface of the hydrogen absorber is protected by being covered with a hydrogen-permeable protective film, the durability and reliability of the hydrogen sensor can be improved.

  In the hydrogen sensor having the above-described configuration, the hydrogen-permeable protective film is made of porous silicon nitride, silicon oxide, or polyimide.

  Porous silicon nitride, silicon oxide, and polyimide are all excellent in hydrogen selective permeability, so if the exposed surface of the hydrogen absorber is covered with a protective film made of each of these materials, the effects of other combustible gases are affected. High efficiency can be eliminated, and the sensitivity of the hydrogen sensor can be increased. In addition, since each of these materials can be easily formed by a vacuum film forming method, the productivity of the hydrogen sensor can be improved.

  On the other hand, the present invention relates to a method for detecting hydrogen, in which the present invention relates to a semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium attached on the semiconductor, and an attachment position of the hydrogen absorber on the semiconductor. Using a hydrogen sensor comprising at least one pair of electrodes arranged at a position not conducting with the hydrogen absorber, the change in resistance value of the semiconductor measured between the at least one pair of electrodes to the hydrogen absorber The configuration is such that the presence or absence of hydrogen absorption and the amount of hydrogen absorption are detected.

  Thus, when the presence / absence of hydrogen absorption into the hydrogen absorber and the hydrogen absorption amount are detected from the change in the resistance value of the semiconductor measured between at least one pair of electrodes, when applied to a hydrogen gas utilization device, for example, a low concentration It can be applied to the control of detecting hydrogen gas leakage from the cylinder at the stage of detecting hydrogen gas and forcibly stopping the hydrogen gas utilization device at the stage of detecting high concentration hydrogen gas. The scope of application can be expanded.

  The hydrogen sensor according to the present invention includes a semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium attached on the semiconductor, and the hydrogen absorber on the semiconductor across the attachment position of the hydrogen absorber. And at least one pair of electrodes arranged at a position not conducting, the hydrogen absorbing capacity of the hydrogen absorber does not reach a saturation state up to a concentration of about 2.0%, and a hydrogen absorber made of palladium was used. Compared to the case, the detection range of the hydrogen gas concentration can be expanded, and stepwise or continuous detection of the hydrogen gas concentration in the atmosphere becomes possible.

  The method for detecting hydrogen according to the present invention includes a semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium attached on the semiconductor, and the hydrogen on the semiconductor across the attachment position of the hydrogen absorber. Since a hydrogen sensor having at least one pair of electrodes arranged at a position not conducting with the absorber is used, the detection range of the hydrogen gas concentration can be expanded as compared with a case where a hydrogen absorber made of palladium is used. Thus, stepwise or continuous detection of the hydrogen gas concentration in the atmosphere becomes possible. And since it detects not only the presence or absence of hydrogen absorption into the hydrogen absorber from the resistance change of the semiconductor measured between at least one pair of electrodes, but also detects the amount of hydrogen absorption into the hydrogen absorber, When applied to a hydrogen gas utilization device, for example, when a low concentration hydrogen gas is detected, leakage of hydrogen gas from the cylinder is detected, and when a high concentration hydrogen gas is detected, the hydrogen gas utilization device is forcibly detected. This can be applied to the control of stopping, and the application range of the hydrogen sensor can be expanded.

<First Embodiment>
Hereinafter, a first example of a hydrogen sensor according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a hydrogen sensor according to the first embodiment, and FIG. 2 is a plan view of the hydrogen sensor according to the first embodiment.

  As is clear from these drawings, the hydrogen sensor A according to the first embodiment includes an insulating substrate 1, a layered semiconductor 2 formed on substantially the entire upper surface of the insulating substrate 1, and a central portion of the upper surface of the semiconductor 2. The formed hydrogen absorber 3, the inner electrodes 5 and 5 formed on the left and right sides of the hydrogen absorber 3 on the surface of the semiconductor 2, and the outer surfaces of the inner electrodes 5 and 5 on the surface of the semiconductor 2 The outer electrodes 6 and 6 are formed. The inner electrodes 5, 5 and the outer electrodes 6, 6 are formed so as not to be electrically connected to the hydrogen absorber 3.

The insulating substrate 1 can be formed of glass such as SiO ₂ , quartz, ceramic such as Al ₂ O _3, silicon not doped with ions, or the like. Since the insulating substrate 1 only needs to have insulating properties on the surfaces on which the semiconductor 2 and the electrodes 5 and 6 are formed, a substrate in which an insulating layer is coated on the surface of a conductive substrate can also be used.

  The semiconductor 2 is formed by laminating ITO (indium tin oxide), GaN, or n-type Si doped with P as a semiconductor. This semiconductor is preferably an insulator, but it is particularly desirable to use a semiconductor doped with ions. As this type of semiconductor, an n-type semiconductor in which silicon is ion-doped with an element such as P, As or Sb, which is a group V element, or a p-type semiconductor in which silicon is group-doped with a group III element such as B, etc. Can be used. Furthermore, n-type or p-type SiC, Ge, SiGe, GaAs, GaN, or the like can be used as a semiconductor material constituting the semiconductor 2.

  The hydrogen absorber 3 absorbs hydrogen when hydrogen exists in the atmosphere, and releases the absorbed hydrogen when hydrogen disappears from the atmosphere, and is formed of gold or an alloy of gold and palladium. In the case where the hydrogen absorber 3 is formed of an alloy of gold and palladium, it is desirable to suppress the composition ratio of palladium to about 10% in order to make the hydrogen absorption capacity the same as that of gold alone. The hydrogen absorber 3 needs to be formed in a pattern that does not conduct between the electrodes 5 and 5 and between the electrodes 6 and 6. In the pattern formation of the hydrogen absorber 3, a photolithography method is preferably used.

  The hydrogen absorber 3 can be formed in a continuous film shape as shown in FIGS. 1 and 2, but in order to prevent conduction between the electrodes 5 and 5 and between the electrodes 6 and 6, It is particularly desirable that the absorber material is dispersed and arranged in an island-like state and functions as an insulator as a whole.

  The hydrogen absorber 3 in which the granular hydrogen absorber material is dispersed and arranged in an island-like state is formed when the hydrogen absorber 3 is formed by a vacuum film formation method such as a vacuum evaporation method or a sputtering method. The film can be formed by stopping the film formation at a stage before being performed. Specifically, an insulator having a resistance value of about 1 MΩ can be obtained by suppressing the layer thickness of the hydrogen absorber material deposited on the semiconductor 2 to about 0.5 nm to 5 nm.

  Further, the vertical width of the hydrogen absorber 3 is slightly shorter than the vertical width of the insulating substrate 1, and the horizontal width is formed to be a fraction of the horizontal width of the insulating substrate 1. Thereby, as shown in FIGS. 1 and 2, the semiconductor 2 is exposed on both the left and right sides of the hydrogen absorber 3.

  The inner electrodes 5 and 5 and the outer electrodes 6 and 6 can be made of any good conductive material such as Au or Al. However, in order to simplify the manufacturing process of the hydrogen sensor and reduce its cost, hydrogen absorption When the body 3 is made of Au, the electrodes 5 and 6 are also preferably made of Au. Each of these electrodes 5 and 6 can be formed by a vacuum deposition method, a sputtering method, a screen printing method, or the like.

  The hydrogen sensor A according to the first embodiment configured as described above is installed in a measurement environment, and measures the voltage between the inner electrodes 5 and 5 while applying a predetermined current between the outer electrodes 6 and 6. Hydrogen can be detected. That is, when hydrogen gas exists in the installation environment of the hydrogen sensor A, hydrogen is taken into the hydrogen absorber 3 of the hydrogen sensor A, and the portion of the semiconductor 2 that is in contact with the hydrogen absorber 3 is the hydrogen to the hydrogen absorber 3. Since the state of the charge carrier changes due to absorption, the resistance value of the semiconductor 2 changes accordingly. Further, when the hydrogen gas is exhausted from the installation environment of the hydrogen sensor A, hydrogen is released from the hydrogen absorber 3, so that the resistance value of the semiconductor 2 returns to the origin and becomes usable again. In this case, unlike the conventional hydrogen sensor, the hydrogen sensor A according to the first embodiment does not detect hydrogen based on the oxidation-reduction reaction. Therefore, unlike the conventional hydrogen sensor, the hydrogen sensor A is detected after the detection of hydrogen. It is not necessary to re-oxidize by heating at a high temperature of 200 ° C. to 300 ° C., and it can be reused by simply leaving it in a room temperature environment without hydrogen after detection.

  The hydrogen sensor A according to the first embodiment has a great feature in that hydrogen can be detected at room temperature unlike a conventional hydrogen sensor, but hydrogen can be detected even in a high-temperature atmosphere. Of course.

<Second Embodiment>
Hereinafter, a second example of the hydrogen sensor according to the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view of the hydrogen sensor according to the second embodiment, and FIG. 4 is a plan view of the hydrogen sensor according to the second embodiment.

  As is clear from these drawings, the hydrogen sensor B according to the second embodiment covers the exposed surface of the hydrogen absorber with a hydrogen-permeable protective film 17 and a thin film between the semiconductor 2 and the hydrogen absorber 3. The insulating layer 14 is interposed, and the exposed surfaces of the electrodes 5 and 6 and the upper surface of the semiconductor 2 are covered with the thin film insulating layer 14. Others are the same as the hydrogen sensor A according to the first embodiment.

  The hydrogen permeable protective film 17 can be formed of porous silicon nitride, silicon oxide, polyimide, or the like. Since each of these materials is excellent in selective hydrogen permeability, when the exposed surface of the hydrogen absorber 3 is covered with the protective film 17 made of these materials, the hydrogen in the atmosphere is selectively absorbed. Therefore, the influence of other combustible gases can be eliminated efficiently, and the sensitivity of the hydrogen sensor can be further increased. In addition, since each of these materials can be easily formed by a vacuum film forming method, the productivity of the hydrogen sensor can be improved. Furthermore, since the exposed surface of the hydrogen absorber 3 can be protected by covering with the protective film 17, the durability and reliability of the hydrogen sensor can be improved.

  The thin film insulating layer 14 can also be formed of porous silicon nitride, silicon oxide, polyimide, or the like. When the thin film insulating layer 14 is formed on the predetermined surface in this manner, the surface of the semiconductor 2 is protected by the thin film insulating layer 14, so that the durability and reliability of the hydrogen sensor can be improved.

  In each of the above embodiments, the film-like semiconductor 2 is formed on the insulating substrate 1, but the configuration of the semiconductor 2 is not limited to this, and a bulk semiconductor or semiconductor particles are consolidated. It is also possible to use a molded body molded into a desired shape.

<Experimental example>
Various hydrogen sensors having different materials for the hydrogen absorber 3 were produced, and hydrogen gas detection experiments were performed. The effects of the hydrogen sensor according to the present invention will be clarified with the configuration and experimental results of various hydrogen sensors as samples.

  A hydrogen sensor as a sample is formed by forming a GaN film doped with Si having a thickness of 0.1 μm as a semiconductor 2 on a sapphire substrate 16 mm long and 9 mm wide, and absorbing hydrogen 5 mm long and 7 mm wide in the center of the GaN film Body 3 was formed. In addition, the inner electrode 5 and the outer electrode 6 having a two-layer structure in which the base is made of Ti and the upper layer is made of Au are formed at a position not in contact with the hydrogen absorber 3 on the GaN film with a length of 7.5 mm and a width of 1.2 mm. The external configuration of the hydrogen sensor A according to the first embodiment is assumed.

  The composition of the hydrogen absorber 3 in each sample is shown in FIG. Sample B0 is Pd 100%, Sample B1 is Pd 95% and Au 5%, Sample B2 is Pd 80% and Au 20%, Sample B3 is Pd 77% and Au 23%, Sample B4 is Pd 64.5% and Au 35.5%, Sample B5 is Pd44 Sample B6 is Pd27% and Au73%, Sample B7 is Pd11.5% and Au is 88.5%, Sample B8 is Pd5% and Au is 95%, Sample B9 is Pd3% and Au is 97%, Sample BA is Au100% It is. Here, the ratio is an atomic ratio.

  The hydrogen absorber 3 was formed using a sputtering apparatus SC-701HMC manufactured by Sanyu Electronics Co., Ltd. under film forming conditions in which the current value was 15 mA, the sputtering gas was Ar, the degree of vacuum was 15 Pa, and the sputtering time was 15 minutes. The configuration of the target is as shown in FIG. Sample B0 was formed using a Pd target. Sample BA was formed using an Au target. For Samples B1 to B9, a target in which an Au chip having a side of 10 mm and a thickness of 0.7 mm was attached to the surface of the Pd target in the required arrangement shown in FIG. 6 was used. In FIG. 6, the part on the donut is a place where a large amount of sputtering is performed on the target.

  Each of these materials was simultaneously housed in a hydrogen sensor measurement chamber, and the sensor output was measured at 130 ° C. in an air atmosphere and a hydrogen gas-containing air atmosphere. The results are shown in FIGS. FIG. 7 shows that for samples B0, B7, and BA, after confirming that the sensor output in the atmosphere is 2.5 V, the hydrogen gas concentration in the atmosphere is 3%, 2%, 1%, 0.5%, It is a figure which shows the change of the sensor output when it reduces with 0.3% and 0%, and FIG. 8 plots the sensor output when it will be in an equilibrium state with each hydrogen gas concentration. Each hydrogen gas concentration was switched after the sensor output was in a sufficiently balanced state.

  As is clear from FIGS. 7 and 8, the sample B0 with 100% Pd is saturated with hydrogen gas absorption capacity at a hydrogen gas concentration of about 0.3%, and the hydrogen gas concentration is changed within the range of 0.3% to 3%. Therefore, it is difficult to detect a hydrogen gas concentration of 0.3% or more. In contrast, the sample B7 of Pd 11.5% and Au 88.5% and the sample BA of Au 100% do not saturate the hydrogen gas absorption capacity up to a hydrogen gas concentration of about 2%, and range from 0.3% to 2%. The hydrogen gas concentration can be detected. Therefore, stepwise or continuous detection of the hydrogen gas concentration in this range is possible, and the application range of the hydrogen sensor can be expanded.

  Samples B8 and B9 are substantially equivalent to sample B7, and samples B1 to B6 have values close to sample B0. Moreover, when the same experiment was conducted about the hydrogen sensor which concerns on 2nd Embodiment, the result similar to the said experimental example was obtained.

It is sectional drawing of the hydrogen sensor which concerns on 1st Embodiment. It is a top view of the hydrogen sensor concerning a 1st embodiment. It is sectional drawing of the hydrogen sensor which concerns on 2nd Embodiment. It is a top view of the hydrogen sensor concerning a 2nd embodiment. It is a table | surface figure which shows the composition of the hydrogen absorber of each sample. It is a block diagram of the target used for manufacturing the hydrogen absorber of each sample. It is a graph which shows the effect of the hydrogen sensor which concerns on this invention compared with the hydrogen sensor which concerns on a comparative example. It is a graph which shows the effect of the hydrogen sensor which concerns on this invention compared with the hydrogen sensor which concerns on a comparative example.

Explanation of symbols

A, B Hydrogen sensor 1 Insulating substrate 2 Semiconductor 3 Hydrogen absorber 5 Inner electrode 6 Outer electrode 14 Thin film insulating layer 17 Hydrogen permeable protective film

Claims (9)

  A semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium containing gold as a main component, and the hydrogen absorber on the semiconductor across the attachment position of the hydrogen absorber; A hydrogen sensor comprising: at least one pair of electrodes disposed at a position where electrical connection is not established.   The hydrogen sensor according to claim 1, wherein a semiconductor formed in a layered manner on an insulating substrate is used as the semiconductor.   The hydrogen sensor according to claim 1, wherein a non-oxide semiconductor is used as the semiconductor. Claims wherein the non-oxide semiconductor, silicon, and wherein the silicon carbide, germanium, silicon germanium, gallium arsenide, gallium nitride, that one of the carbon-containing with non-oxide semiconductor whose main component Item 4. The hydrogen sensor according to Item 3.   The hydrogen sensor according to claim 1, wherein the hydrogen absorber is formed directly on the semiconductor.   The hydrogen sensor according to any one of claims 1 to 4, wherein a thin film insulating layer is interposed between the semiconductor and the hydrogen absorber.   The hydrogen sensor according to claim 1, wherein an exposed surface of the hydrogen absorber is covered with a hydrogen-permeable protective film.   The hydrogen sensor according to claim 7, wherein the hydrogen-permeable protective film is made of silicon nitride, silicon oxide, or polyimide.   A semiconductor, a hydrogen absorber made of gold or an alloy of gold and palladium attached to the semiconductor, and a position where the hydrogen absorber on the semiconductor is not electrically conductive with the hydrogen absorber attached. Using a hydrogen sensor provided with at least one pair of electrodes, the presence or absence of hydrogen absorption into the hydrogen absorber and the amount of hydrogen absorption are detected from the change in resistance of the semiconductor measured between the at least one pair of electrodes. A method for detecting hydrogen.

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