JP2015058399A - Hydrogen permeation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen permeation structure having high hydrogen permeation performance and proton conductivity and suppressing the peeling of a proton conductor film.SOLUTION: A hydrogen permeation structure comprises: an Si substrate 101 having a surface formed to be porous; a lower proton permeable membrane 104; an electrolyte membrane 105 and an upper proton permeable membrane 106. The upper and lower proton permeable membranes 104, 106 have a perovskite crystal structure represented by A1(DRu)Oand satisfy 0<x1≤0.5, 0.3≤y≤0.8 and z1<3. The electrolyte membrane 105 has a perovskite crystal structure represented by A2(EG)Oand satisfies 0<x2≤0.5, 0.2≤w≤0.6 and z2<3.

Description

  The present invention relates to a hydrogen permeable structure that can be used in a hydrogen addition device, a fuel cell, a steam electrolysis device, and the like.

  Patent Document 1 discloses that hydrogen is stored and transported by adding hydrogen to an aromatic hydrocarbon such as benzene as a technique for storing or transporting hydrogen safely and easily (see, for example, Patent Document 1). ).

To store hydrogen, 6 hydrogen atoms are added to toluene (C ₇ H ₈ ) to give methylcyclohexane (C ₇ H ₁₄ ). Hydrogen is obtained by returning methylcyclohexane to toluene to supply hydrogen.

  Toluene and methylcyclohexane are easy to handle because they are liquid at room temperature. Therefore, it can be stored and transported in the same manner as gasoline or kerosene.

  Further, in a fuel cell using hydrogen, when a proton conductor that conducts hydrogen ions (protons) is used as an electrolyte, water is not generated at the electrode on the hydrogen supply side, and hydrogen is not easily diluted.

  Examples of the proton conductor include a Nafion membrane manufactured by DuPont, or Ba-Zr-YO of perovskite oxide (see, for example, Patent Document 2). When a proton conductor of a perovskite oxide is used as a hydrogen permeable structure such as a fuel cell, it is usually used at a high temperature of several hundred degrees Celsius or higher in order to ensure sufficient proton conductivity.

  In order to improve proton conductivity, the proton conductor film having proton conductivity having anisotropy is obtained by orienting the thin film in a specific crystal orientation so that a grain boundary that inhibits proton conduction is not generated as much as possible. It is disclosed (see, for example, Patent Document 3).

  Note that a proton conductor film having no grain boundary is disclosed by epitaxially growing a proton conductor film on a single crystal substrate (see, for example, Non-Patent Document 1).

Japanese Patent No. 3812880 Japanese Examined Patent Publication No. 7-21481 JP 2003-147514 A

NATURE MATERIALS, 844-852 (2010)

  It has high hydrogen permeation performance and proton conduction, and it is difficult to suppress peeling of the proton conductor membrane.

In order to solve the conventional problem, a hydrogen permeable structure as an example of the present disclosure includes a proton permeable membrane including a perovskite oxide having proton electron mixed conductivity on a Si substrate having a porous portion; An electrolyte membrane containing a perovskite oxide having proton conductivity is sequentially laminated, and the proton permeable membrane and the electrolyte membrane are epitaxially grown with the crystal orientation of the Si substrate aligned, and the proton permeable membrane has a composition formula A1 _{1. -x1} (D _{1 -y} Ru _y ) O _z1 (where A1 is at least one element selected from Ba, Sr and Ca, D is Zr, Hf, Y, La, Ce, Gd, In, Ga) And at least one element selected from Al), the electrolyte membrane is represented by a composition formula A2 _1-x2 (E _1-w G _w ) O _z2 (where A2 is at least one selected from Ba, Sr and Ca). Element, E is at least one element selected from Zr, Hf, In, Ga and Al, G is at least one element selected from Y, La, Ce and Gd), 0 <x1 ≦ 0.5, 0 <x2 ≦ 0.5, 0.3 ≦ y ≦ 0.8, 0.2 ≦ w ≦ 0.6, z1 <3, and z2 <3 are satisfied. With this configuration, it is possible to suppress separation of the membrane and improve proton conductivity. In addition, since both the proton permeable membrane and the electrolyte membrane are perovskite oxides, the electrolyte membrane is easily epitaxially grown on the proton permeable membrane, and the adhesion strength of the membrane is increased. Furthermore, since the proton permeable membrane and the electrolyte membrane are epitaxially grown, there is an effect that the atomic arrangement at the membrane interface is less disturbed and proton conduction is facilitated in the vertical direction of the membrane. Further, since the proton permeable membrane has proton conductivity and electron conductivity, it can be used as an electrode membrane, and it is not necessary to arrange a metal membrane or the like as an electrode membrane between the substrate and the proton permeable membrane.

  According to the hydrogen permeable structure as an example of the present disclosure, the hydrogen permeable structure has high hydrogen permeability and proton conduction, and suppresses peeling of the proton conductor membrane.

The principal part expanded sectional view which shows an example of a hydrogen permeable structure. The principal part expanded sectional view which shows an example of a hydrogen permeable structure. The principal part expanded sectional view which shows an example of a hydrogen permeable structure. The principal part expanded sectional view which shows an example at the time of evaluation of a hydrogen permeable structure.

A hydrogen permeable structure according to one embodiment of the present disclosure includes a Si substrate having a surface on which a porous portion is formed, a proton permeable membrane that is a single crystal formed on the surface, and an upper portion of the proton permeable membrane. The Si substrate, the proton permeable membrane, and the electrolyte membrane are aligned in crystal orientation, and the proton permeable membrane has a composition formula A1 _1-x1 (D _{1- y} Ru _y ) O _z1 and a perovskite crystal structure, A1 is at least one element selected from Ba, Sr and Ca, and D is Zr, Hf, Y, La, Ce, Gd, In , Ga and Al, satisfying 0 <x1 ≦ 0.5, 0.3 ≦ y ≦ 0.8, and z1 <3, and the electrolyte membrane has a composition formula A2 _1-x2 ( E _1-w G _w ) Perovskite crystal structure represented by O _z2 , A2 is at least one element selected from Ba, Sr and Ca, E is at least one element selected from Zr, Hf, In, Ga and Al, and G is selected from Y, La, Ce and Gd At least one element satisfying 0 <x2 ≦ 0.5, 0.2 ≦ w ≦ 0.6, and z2 <3.

(Knowledge that became the basis of this disclosure)
In a structure having a porous Si substrate, an electrode film which is a hydrogen-permeable Pd or Pd alloy thin film formed on the surface of the Si substrate, and a proton conductor film formed on the electrode film, the proton conductivity and It has been found that it has hydrogen permeability and it is difficult to suppress peeling of the proton conductor membrane.

  This is because it has been difficult to epitaxially grow a thin film of Pd or Pd alloy on the Si substrate. Also, when a thin film of Pd or Pd alloy is formed after the formation of the epitaxially grown proton conductor film, it is difficult to remove the substrate on which the proton conductor film is formed and expose the proton conductor film. This is because.

  The present inventors have found a hydrogen permeable structure having proton conductivity and hydrogen permeability according to the composition of the proton permeable membrane and the electrolyte and suppressing the peeling of the proton conductor membrane.

  Hereinafter, embodiments will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a configuration example of the hydrogen permeable structure 100 according to the present embodiment. A hydrogen permeable structure 100 shown in FIG. 1 includes a Si substrate 101 having a surface on which a porous portion 102 is formed, a buffer film 103, a lower proton permeable film 104, an electrolyte membrane 105, and an upper proton permeable film 106. It has. The buffer membrane 103, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are sequentially formed on the porous portion 102 of the Si substrate 101 from bottom to top. The Si substrate 101, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 have the same crystal orientation.
2 has a plurality of holes penetrating the Si substrate 101 and the buffer film 103. The hydrogen permeable structure 100 shown in FIG. As a result, the surface of the lower proton permeable membrane 104 of the hydrogen permeable structure 100 is exposed to the outside.

  In order to manufacture the hydrogen permeable structure 100 shown in FIG. 2, for example, after forming the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106, a technique such as wet etching or dry etching is used. The substrate 101 and the buffer film 103 are processed into desired shapes.

<Si substrate 101>
The Si substrate 101 has a surface on which the porous portion 102 is formed. A buffer membrane 103, a lower proton permeable membrane 104, an electrolyte membrane 105, and an upper proton permeable membrane 106, which will be described later, are formed in this order from the bottom to the top on the surface where the porous portion 102 is formed. Hereinafter, the surface on which the porous portion 102 is formed is also referred to as a first surface, and the surface facing the first surface is also referred to as a second surface.

  Desirably, the surface on which the porous portion 102 is formed has a desired crystal plane exposed and high flatness. In addition, the Si substrate 101 including the surface on which the porous portion 102 is formed is preferably a single crystal.

  Here, the desired crystal plane means a plane in which the crystal orientation is aligned with the buffer film 103, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 formed on the upper portion. Thereby, the buffer film 103, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are formed epitaxially on the surface where the porous portion 102 is formed.

  Examples of desired crystal planes are (100) plane, (110) plane, or (111) plane.

  The porous part 102 is formed on the surface of the Si substrate 101. The porous part 102 means a plurality of holes formed on the surface of the Si substrate 101. The average pore diameter of the porous portion 102 is desirably in the range of 10 nm to 500 nm.

  The opening ratio, which is the ratio of the area of the opening portion (hole portion) to the surface area of the Si substrate 101, is preferably 30% or more and 70% or less. Thereby, the stress remaining in the lower proton permeable membrane 104 and the electrolyte membrane 105 can be relaxed, and peeling at the membrane interface can be suppressed.

  The depth of the porous portion 102 is desirably 1 μm or more and 100 μm or less.

  The Si substrate 101 having a surface on which the porous portion 102 is formed is formed by anodic oxidation by applying a positive potential to the Si substrate immersed in hydrofluoric acid or the like, and applying and patterning a photoresist on the Si substrate and immersing it in a solvent. It is produced by etching or the like that dissolves the Si substrate.

  As shown in FIG. 2, the Si substrate 101 may have a plurality of holes penetrating from the first surface to the second surface.

<Buffer film 103>
The buffer film 103 is formed on the upper surface of the porous part 102. The crystal orientation of the buffer film 103 is aligned with the crystal orientation of the surface on which the porous portion 102 is formed.

The material of the buffer film 103 is preferably an oxide. Examples of the material of the buffer film 103 are MgO and SrRuO ₃ . Note that, between the buffer film 103 and the Si substrate 101, stabilized zirconia (a material obtained by substituting 4 to 10 mol% of ZrO ₂ with Y ₂ O ₃ ), CeO ₂ , (La, Sr) MnO _3, etc. An oxide film may be disposed. Thereby, the buffer film 103 is easily epitaxially grown on the Si substrate 101. That is, the crystal orientation of the surface of the Si substrate 101 and the crystal orientation of the buffer film 103 are easily aligned. An example of the thickness of the buffer film 103 is in the range of 5 nm to 150 nm.

<Lower proton permeable membrane 104>
The lower proton permeable membrane 104 is formed on the buffer membrane 103. The crystal orientation of the lower proton permeable membrane 104 is aligned with the crystal orientation of the surface on which the buffer film 103 and the porous portion 102 are formed.

  When the hydrogen permeable structure does not have the buffer membrane 103, the lower proton permeable membrane 104 is formed on the upper surface on which the porous portion 102 is formed. The crystal orientation of the lower proton permeable membrane 104 is aligned with the crystal orientation of the surface on which the porous portion 102 is formed.

The lower proton permeable membrane 104 is made of a material having a perovskite crystal structure. The perovskite oxide is generally represented by a chemical formula of ABO _{3 and} has a cubic unit cell. Alkaline earth metals such as Ba, Sr, and Ca at the apex site of the cubic crystal, Zr, Hf, Y, La, Ce, Gd, In, Ga, Al, Ru, etc. at the B site of the cubic crystal center O (oxygen) is arranged in the face center of the metal, cubic crystal. When the B site is occupied only by a tetravalent metal, the crystal structure has no oxygen deficiency, but when a trivalent metal is included, the same oxygen deficiency as the number of atoms of the metal is included. Due to this oxygen deficiency, the perovskite oxide has proton conductivity. Further, since RuO ₂ is a conductive oxide and exhibits metallic conductivity, the perovskite oxide has electronic conductivity when it contains Ru.

A specific material example of the lower proton permeable membrane 104 is an oxide having a perovskite crystal structure represented by a composition formula A1 _1-x1 (D _1-y Ru _y ) O _z1 . A1 is at least one element selected from Ba, Sr and Ca, and D is at least one element selected from Zr, Hf, Y, La, Ce, Gd, In, Ga and Al. The relations 0 <x1 ≦ 0.5, 0.3 ≦ y ≦ 0.8, and z1 <3 are satisfied.

Further, the element A1 contains at least Ba, and may contain at least one element selected from Sr, Ca, and Mg. For example, the element of A1 is BaαA1 ′ _1- α (α> 0). An example of A1 ′ is at least one kind of Sr, Ca, and Mg.

The element of D contains at least Zr, and may contain at least one element selected from Hf, Y, La, Ce, Gd, In, Ga, and Al. For example, the element of D is ZrβD ′ _1- β (β> 0). An example of D ′ is at least one of Hf, Y, La, Ce, Gd, In, Ga, and Al.

  When x1 is in the range of 0 <x1 ≦ 0.5, the A site of the perovskite oxide is lost. As a result, the degree of freedom of the crystal structure of the lower proton permeable membrane 104 is increased, and the difference between the lattice constant of the lower proton permeable membrane and the lattice constant of the buffer membrane 103 is easily relaxed. This is desirable because it facilitates epitaxial growth on the film 103 and improves proton conductivity.

  Furthermore, since the A site is deficient, protons are easily taken into the lower proton permeable membrane 104, so that the lower proton permeable membrane 104 is filled with protons and proton conduction is facilitated.

  In addition, when y is in the range of 0.3 ≦ y ≦ 0.8, both high electron conductivity and high proton conductivity of the lower proton permeable membrane 104 can be achieved.

  In addition, it is shown that oxygen deficiency occurs when a part of the tetravalent metal at the B site is substituted with a trivalent metal, and the amount of oxygen deficiency is about 0.4 at the maximum. It is desirable that the range is 6 ≦ z1 <3.

  The lower proton permeable membrane 104 desirably has a thickness in the range of 50 nm to 500 nm.

<Electrolyte membrane 105>
The electrolyte membrane 105 is formed on the lower proton permeable membrane 104. The electrolyte membrane 105 is made of a material having a perovskite crystal structure having proton conductivity.
A specific material example of the electrolyte membrane 105 has a perovskite crystal structure represented by a composition formula A2 _1-x2 (E _1-w G _w ) O _z2 . A2 is at least one element selected from Ba, Sr and Ca, E is at least one element selected from Zr, Hf, In, Ga and Al, and G is selected from Y, La, Ce and Gd At least one element. 0 <x2 ≦ 0.5, 0.2 ≦ w ≦ 0.6, and z2 <3 are satisfied.

Further, the element A2 contains at least Ba, and may contain at least one element selected from Sr, Ca, and Mg. For example, the element of A2 is BaγA2 ′ _1- γ (γ> 0). An example of A2 ′ is at least one kind of Sr, Ca, and Mg.

Further, the element of E contains at least Zr, and may contain at least one element selected from Hf, Y, La, Ce, Gd, In, Ga, and Al. For example, the element of D is ZrδD ′ ₁₋ δ (δ> 0). An example of D ′ is at least one of Hf, Y, La, Ce, Gd, In, Ga, and Al.

The element of G contains at least Y and may contain at least one element selected from La, Ce and Gd. For example, the element of G is YεD ′ ₁₋ ε (ε> 0).

  When x2 is in the range of 0 <x2 ≦ 0.5, the A site of the perovskite oxide is lost as described above. As a result, the degree of freedom of the crystal structure of the electrolyte membrane 105 increases, and the difference between the lattice constant of the electrolyte membrane 105 and the lattice constant of the lower proton permeable membrane 104 is easily relaxed, so that the electrolyte membrane 105 becomes lower proton permeable membrane. It is preferable because epitaxial growth is easily performed on the layer 104 and proton conductivity is greatly improved.

  Furthermore, since the A site is in a deficient state, protons are easily taken into the electrolyte membrane 105, so that the electrolyte membrane 105 is filled with protons and proton conduction is facilitated.

  Moreover, by satisfying 0.2 ≦ w ≦ 0.6, the oxygen deficiency amount of the electrolyte membrane 105 becomes a desirable amount, and proton conductivity is improved.

  Note that the relationship of z2 <3 is as described for the lower proton permeable membrane 104 described above. Since the oxygen deficiency is about 0.4 at the maximum, it is desirable that the oxygen deficiency be in the range of 2.6 ≦ z2 <3. The electrolyte membrane 105 preferably has a thickness in the range of 100 nm to 5000 nm.

  Note that the buffer membrane 103, the lower proton permeable membrane 104, and the electrolyte membrane 105 desirably have large lattice constants from the bottom to the top. Further, the difference between the lattice constant of the buffer membrane 103 and the lattice constant of the lower proton permeable membrane 104, and the difference between the lattice constant 4 of the lower proton permeable membrane 104 and the lattice constant of the electrolyte membrane 105 are 0.03 nm or less. More desirable.

For example, the lattice constant of SrRuO ₃ which is an example of the buffer film 103 is 0.394 nm, and the lattice constant of (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 which is an example of the lower proton permeable film 104 is The lattice constant of Ba _0.8 Zr _0.7 Y _0.3 O _2.85 which is 0.415 nm and is an example of the electrolyte membrane 105 is 0.425 nm, which satisfies the above relationship.

<Upper proton permeable membrane 106>
The upper proton permeable membrane 106 is formed on the electrolyte membrane 105. An example of the material of the upper proton permeable membrane 106 is an oxide having a perovskite crystal structure represented by a composition formula A1 _1-x1 (D _1-y Ru _y ) O _z1 , similarly to the lower proton permeable membrane 104. A1 is at least one element selected from Ba, Sr and Ca, and D is at least one element selected from Zr, Hf, Y, La, Ce, Gd, In, Ga and Al. The relations 0 <x1 ≦ 0.5, 0.3 ≦ y ≦ 0.8, and z1 <3 are satisfied.

  An example of the thickness of the upper proton permeable membrane 106 is desirably in the range of 50 nm to 500 nm.

<Modification>
As shown in FIG. 3, a hydrogen permeable structure 100 without the upper proton permeable membrane 106 may be produced. A hydrogen permeable structure 100 shown in FIG. 3 includes a Si substrate 101, a buffer film 103, a lower proton permeable film 104, and an electrolyte film 105.

  By bringing the mesh into contact with the electrolyte membrane 105 as an electrode, the hydrogen permeable structure 100 has a function of flowing electrons and hydrogen at the same time as the upper proton permeable membrane 106. Examples of the mesh material are Pt, Au, Pd, Ag, and the like.

  A buffer film (not shown) may be further disposed between the porous portion 102 of the Si substrate 101 and the buffer film 103. By arranging the buffer film, it is possible to reduce the cracking of the buffer film 103 due to the difference in the linear expansion coefficient between the Si substrate 101 and the buffer film 103.

The buffer film is preferably made of a material having a linear expansion coefficient between the linear expansion coefficient of the Si substrate 101 and the linear expansion coefficient of the buffer film 103. For example, when an MgO film is used as the buffer film 103, the linear expansion coefficient of the Si substrate 101 (linear expansion coefficient: 2.6E ⁻⁶ K ⁻¹ ) and the linear expansion coefficient of the MgO film (linear expansion coefficient: 13.5E). ⁻⁶ K ⁻¹ ), and a material having a gland expansion coefficient in the range of 4E ^{−6 to} 10E ⁻⁶ K ⁻¹ is preferably used as the buffer film material. For example, it is more desirable to use a material having a linear expansion coefficient of about 7E- ^{6K- 1} as the buffer film.

In particular, when an MgO film is used as the buffer film 103, a spinel material (MgAl ₂ O ₄ ) mainly containing Mg, Al, and O (oxygen) has a linear expansion coefficient of about 7.5E ⁻⁶ K ^−1. In addition, since it contains the same element as the MgO film, the adhesion strength between the buffer film 103 and the buffer film is increased, which is desirable.

<Manufacturing method>
The hydrogen permeable structure 100 according to the present embodiment can be manufactured by the method described below.

<S1>
A Si substrate 101 having a surface on which the porous portion 102 is formed is prepared. For example, the porous portion 102 is formed by anodizing the surface of the Si substrate 101.

  An example of the Si substrate 101 is a single crystal Si substrate. For example, an example of a single crystal Si substrate has a thickness of 0.5 mm, a diameter (Φ) of 2 inches, an N type, a plane orientation (100), and a specific resistance of 1 Ω · cm. In the example of the porous portion 101, the average pore diameter is 50 nm, the aperture ratio is 50%, and the depth is 10 μm.

<S2>
A buffer film 103 is formed on the surface of the Si substrate 101 where the porous portion 102 is formed. For example, the buffer film 103 is formed on the Si substrate 101 by sputtering.

The Si substrate 101 is disposed in a rare gas (for example, Ar gas) atmosphere or a mixed gas atmosphere of a rare gas and a reactive gas (for example, O ₂ gas). A metal or a compound is used for the target. A buffer film 103 is formed on the Si substrate 101 by sputtering using a direct current (DC) power supply, a pulsed DC power supply, or a radio frequency (RF) power supply.

For example, when the buffer film 103 is composed of an MgO film, the target is used for Mg. An MgO film is formed by performing reactive sputtering using a DC power source, a pulsed DC power source, or an RF power source in an atmosphere of a mixed gas of Ar gas and O ₂ gas. Further, when using MgO as a target, an MgO film can be formed by sputtering using an RF power source in an atmosphere of Ar gas or a mixed gas of Ar gas and O ₂ gas.

  In order to epitaxially grow the buffer film 103 on the Si substrate 101, it is desirable to form the film by heating the Si substrate 101 to 700 ° C. or higher in order to promote the migration of particles attached to the Si substrate 101. Further, by irradiating the Si substrate 101 with an ion beam to give energy to the particles attached on the Si substrate 101, the migration of the particles can be promoted.

<S3>
A lower proton permeable membrane 104 is formed on the buffer membrane 103. For example, the lower proton permeable film 104 is formed on the buffer film 103 by using a sputtering method.

In a rare gas (for example, Ar gas) atmosphere or a mixed gas atmosphere of a rare gas and a reactive gas (for example, at least one gas selected from O ₂ gas, N ₂ gas, and H ₂ gas), a buffer is provided on the upper part. A Si substrate 101 on which a film 103 is formed is disposed. An example of the target is (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 ). A lower proton permeable film 104 is formed on the buffer film 103 by sputtering using an RF power source.

  Note that since the oxide constituting the lower proton permeable membrane 104 has conductivity, sputtering may be performed using a DC power source or a pulsed DC power source in order to increase the deposition rate.

  Further, when using a metal constituting the lower proton permeable membrane 104 as a target, by performing reactive sputtering using a DC power source, a pulsed DC power source, or an RF power source in a mixed gas atmosphere of a rare gas and a reactive gas, The lower proton permeable membrane 104 can be formed.

  Alternatively, the lower proton permeable membrane 104 can be formed by simultaneously sputtering each target of a single oxide using a plurality of power supplies.

The lower proton permeable membrane 104 uses a binary target or a ternary target combining two or more oxides (for example, Ba _0.9 Zr _0.8 Y _0.2 O _2.9 and SrRuO ₃ ) using a plurality of power supplies. It can also be formed by sputtering at the same time. Even when these targets are used, in a rare gas atmosphere or a mixed gas atmosphere of a rare gas and a reactive gas (for example, at least one gas selected from O ₂ gas, N ₂ gas, and H ₂ gas) The buffer film 103 can be formed by sputtering.

  As in the case where the buffer film 103 is epitaxially grown on the Si substrate 101, the Si substrate 101 is heated to 700 ° C. or higher or the ion beam is buffered in order to promote the migration of particles attached on the buffer film 103. It is desirable to irradiate the surface of the film 103 to give energy to the particles on the buffer film 103.

<S4>
An electrolyte membrane 105 is formed on the lower proton permeable membrane 104. For example, the electrolyte membrane 105 is formed on the lower proton permeable membrane 104 by sputtering.

In a rare gas (for example, Ar gas) atmosphere or a mixed gas atmosphere of a rare gas and a reactive gas (for example, at least one gas selected from O ₂ gas, N ₂ gas, and H ₂ gas), a buffer is provided on the upper part. A Si substrate 101 on which a membrane 103 and a lower proton permeable membrane 104 are formed is disposed. An example of the target is Ba _0.8 Zr _0.7 Y _0.3 O _2.85 . An electrolyte membrane 105 is formed on the lower proton permeable membrane 104 by sputtering using an RF power source.

  In order to increase the deposition rate of the electrolyte membrane 105, conductivity is added to the target by adding a predetermined amount or less of a conductive material to the material constituting the electrolyte membrane 105. A target with conductivity can be sputtered using a DC power source or a pulsed DC power source.

  Further, when the metal constituting the electrolyte film 105 is used as a target, the electrolyte film is formed by reactive sputtering using a DC power source, a pulsed DC power source, or an RF power source in a mixed gas atmosphere of a rare gas and a reactive gas. 105 can be formed.

Alternatively, the electrolyte membrane 105 can be formed by sputtering each target of a single oxide (for example, Ba _0.8 O, ZrO ₂ and Y ₂ O ₃ ) simultaneously using a plurality of power supplies.

In the case of using a binary target or a ternary target in which two or more kinds of oxides are combined, the electrolyte film 105 can be formed by sputtering simultaneously using a plurality of power supplies. Even when these targets are used, sputtering is performed in a rare gas atmosphere or a mixed gas atmosphere of a rare gas and a reactive gas (for example, at least one gas selected from O ₂ gas, N ₂ gas, and H ₂ gas). In particular, the electrolyte membrane 105 can be formed by sputtering.

  As in the case of epitaxially growing the lower proton permeable film 104 on the buffer film 103, the Si substrate 101 is heated to 700 ° C. or higher in order to promote the migration of particles attached on the lower proton permeable film 104, or It is desirable to irradiate the lower proton permeable membrane 104 with an ion beam to give energy to particles on the lower proton permeable membrane 104.

<S5>
An upper proton permeable membrane 106 is formed on the electrolyte membrane 105. For example, the upper proton permeable membrane 106 is formed on the electrolyte membrane 105 by using a sputtering method. The upper proton permeable membrane 106 is formed by the same method as the lower proton permeable membrane 104.

  Note that a buffer film (not shown) may be formed between the porous portion 102 of the Si substrate 101 and the buffer film 103. Note that the buffer film can be formed by a method similar to that for the electrolyte film 105.

  In this embodiment mode, a sputtering method is used as a method for forming each layer. However, the present invention is not limited to this, but a PLD (Pulsed Laser Deposition) method, a vacuum deposition method, an ion plating method, a CVD (Chemical Vapor Deposition) method. It is also possible to use the method or the MBE (Molecular Beam Epitaxy) method.

<Others>
A method for manufacturing the hydrogen permeable structure 100 shown in FIG. 2 will be described. After any of the steps S3, S4, and S5, the Si substrate 101 and the buffer film 103 are processed into desired shapes.

  For example, a photoresist is applied to the second surface of the Si substrate 101 (the surface facing the surface on which the porous portion 102 is formed) using a spin coating method.

  Next, the shape of the photomask is transferred to the photoresist by exposing the photomask on which a desired shape is drawn close to the resist. An example of the desired shape is a cross-sectional pattern having a plurality of holes.

  Next, a mask having a desired pattern is formed on the photoresist by developing the photoresist and removing the exposed portion (positive type) or removing the unexposed portion (negative type).

  As the photoresist, a resist made of a general organic material for photolithography can be used. Note that the photoresist material is preferably selected in consideration of the etching rate ratio between the Si substrate 101 and the buffer film 103.

  In addition, after forming a pattern reversed to a desired shape on the photoresist, a film of an inorganic material such as a metal or an oxide used as a mask is formed, and then the photoresist is dissolved to remove the film on the photoresist by a lift-off method. , An inorganic mask having a desired shape can be formed.

Thereafter, the Si substrate 101 and the buffer film 103 can be processed into desired shapes by performing wet etching or dry etching on the Si substrate 101 and the buffer film 103. For wet etching, hydrofluoric acid, nitric acid, hydrochloric acid, phosphoric acid, acetic acid, aqua regia, etc. can be used. For dry etching, fluorine-based gas (CF ₄ , SF ₆ , CHF ₃ etc.) or Ar gas is used. , And O ₂ gas can be used.

  FIG. 4 shows a configuration example when evaluating the hydrogen permeation performance of the hydrogen permeable structure 100. The configuration shown in FIG. 4 includes a hydrogen permeable structure 100, a DC power supply 301, a first alumina tube 201, and a second alumina tube 202.

  A direct current power supply 301 is connected between the lower proton permeable membrane 104 and the upper proton permeable membrane 106 of the hydrogen permeable structure 100 via an electrode wiring, and the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane. An electric field is applied during 106.

  The first alumina tube 201 is connected to the upper proton permeable membrane 106, and the second alumina tube 202 is connected to the Si substrate 101. The first alumina tube 201 and the second alumina tube 202 can be arranged in different gases. For example, the lower proton permeable membrane 104 is divided into a first space in which the first alumina tube 201 is disposed and a second space in which the second alumina tube 202 is disposed. A film or the like that does not transmit the target gas is disposed between the first space and the second space.

  The first alumina tube 201 and the second alumina tube 202 are made of an upper proton permeable membrane 106 and an Si substrate 101 using a heat-resistant ceramic adhesive (for example, Alemco Ceramer Bond) or sealing glass, respectively. Connect to.

<Conductivity of hydrogen ion (proton) of electrolyte membrane 105>
In the structure shown in FIG. 4, the same type of gas is supplied (for example, Ar: H ₂ = 95: 5) to the first space (upper proton permeable membrane 106 side) and the Si substrate 101 side (second space). The lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are arranged in a desired gas atmosphere (Ar: H ₂ = 95: 5).

  The electrical conductivity of the electrolyte membrane 105 is measured using the impedance analyzer 302. The electrical conductivity of the electrolyte membrane 105 corresponds to the conductivity of hydrogen ions (protons) in the electrolyte membrane 105.

<Hydrogen permeation performance of hydrogen permeable structure 100>
In the structure shown in FIG. 4, water vapor is supplied to the first space (upper proton permeable membrane 106 side), and about 2 V is applied between the upper proton permeable membrane 106 and the lower proton permeable membrane 104 using a DC power supply 301. By applying a voltage (the upper proton permeable membrane 106 side is positive and the lower proton permeable membrane 104 side is negative), water vapor is electrolyzed to hydrogen ions (protons), and hydrogen is supplied from the Si substrate 101 side. It can be taken out.

  At this time, for example, toluene is supplied from the Si substrate 101 side, and the hydrogen permeable structure 100 is heated to about 200 ° C. by an external heater or the like, whereby hydrogen is added to the supplied toluene to obtain methylcyclohexane. it can.

  The hydrogen permeation performance of the hydrogen permeable structure 100 is determined by using a gas chromatograph or the like to determine the amount of hydrogen obtained from the Si substrate 101 side through the hydrogen permeable structure 100 or the amount of methylcyclohexane produced on the Si substrate 101 side. It is evaluated by measuring.

  Further, the voltage applied between the upper proton permeable membrane 106 and the lower proton permeable membrane 104 is reversed (the lower proton permeable membrane 104 side is positive and the upper proton permeable membrane 106 side is negative), and hydrogen permeation is performed. By heating the structure 100 to about 300 ° C. with an external heater or the like, hydrogen can be extracted from methylcyclohexane and returned to toluene. In this case, the hydrogen permeation performance of the hydrogen permeable structure 100 is determined by measuring the amount of hydrogen permeated through the hydrogen permeable structure 100 and obtained from the upper proton permeable membrane 106 side or the amount of toluene produced on the Si substrate 101 side by gas chromatography. It evaluates by measuring using etc.

  In the structure shown in FIG. 4, an external circuit is connected between the lower proton permeable membrane 104 and the upper proton permeable membrane 106. For example, hydrogen is supplied to the upper proton permeable membrane 106 side and oxygen is supplied to the Si substrate 101 side. By raising the temperature of the permeable structure 100 with an external heater or the like, a potential difference is generated between the upper proton permeable membrane 106 and the lower proton permeable membrane 104, and the fuel cell can be operated. Note that oxygen may be supplied to the upper proton permeable membrane 106 side and hydrogen to the Si substrate 101 side. The hydrogen permeation performance of the hydrogen permeable structure 100 in this case is evaluated by measuring the power supplied to the external circuit.

  It should be noted that the specific embodiments or examples made in the section for carrying out the invention are intended to clarify the technical contents of the present invention, and are limited to such specific examples. The present invention should not be interpreted in a narrow sense, and various modifications can be made within the spirit and scope of the present invention.

  The present disclosure is described in detail by way of examples.

Example 1
In Example 1, the hydrogen permeable structure 100 was produced using the manufacturing method described in the embodiment. As the Si substrate 101, a single crystal Si substrate (manufactured by Quantum) was prepared. The Si substrate 101 had a thickness of 0.5 mm, a diameter of 2 inches, an N-type semiconductor, a plane orientation (100), and a specific resistance of 1 Ω · cm. The Si substrate 101 had a surface having a porous portion 102 formed by anodic oxidation. The porous portion 102 had an average pore diameter of 50 nm, an aperture ratio of 50%, and a depth of 10 μm.

<Buffer film 103>
The Si substrate 101 was disposed in the chamber of the sputtering apparatus, and the temperature was raised to 750 ° C. The inside of the chamber was an Ar gas atmosphere, and the pressure was 1 Pa.

  An MgO film was formed as the buffer film 103 on the surface of the Si substrate 101 on which the porous portion 102 was formed by using the sputtering method. MgO was used as a sputtering target. A high frequency (RF) power supply was used and the input power was 50W. The formed buffer film 103 had a thickness of 100 nm.

<Lower proton permeable membrane 104, electrolyte membrane 105, upper proton permeable membrane 106>
Next, the temperature in the chamber of the sputtering apparatus was set to 700 ° C. The inside of the chamber was a mixed gas atmosphere of Ar gas and O ₂ gas (Ar: O ₂ = 8: 2), and the pressure was 1 Pa. And using a high frequency (RF) power source at an input power of 150 W.

Using a sputtering method, a (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 film was formed as the lower proton permeable film 104 on the buffer film 103. As a sputtering target, (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 was used. The formed lower proton permeable membrane 104 had a thickness of 100 nm.

A Ba _0.8 Zr _0.7 Y _0.3 O _2.85 film was formed as the electrolyte film 105 on the lower proton permeable film 104 by sputtering. Ba _0.8 Zr _0.7 Y _0.3 O _2.85 was used as a sputtering target. The formed electrolyte membrane 105 had a thickness of 1000 nm.

A (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 film was formed as the upper proton permeable film 106 on the electrolyte film 105 by sputtering. The upper proton permeable membrane 106 had a thickness of 100 nm.

  Next, the structure shown in FIG. 4 was produced.

First, a plurality of openings having Φ0.5 mm were formed in the Si substrate 101 and the buffer film 103. The length (pitch) between the openings was 1 mm. In particular,
A photoresist pattern having a pitch of 1 mm and having a diameter of 0.5 mm was formed on the surface (second surface) of the Si substrate 101 opposite to the surface on which the buffer film 103 was formed by photolithography.

  An Au film having a thickness of 100 nm was formed on the second surface by sputtering. The photoresist formed on the second surface was removed with a remover using a lift-off method. As a result, an opening having a diameter of 0.5 mm and a pattern of an Au film having a pitch of 1 mm were formed on the second surface of the buffer film 103 and the Si substrate 101.

  The Si substrate 101 was wet etched with hydrofluoric acid, and the MgO film of the buffer film 103 was wet etched with phosphoric acid. The Au film formed on the second surface of the Si substrate 101 was removed by dry etching with Ar gas.

  Next, a first alumina tube 201 was formed on the surface of the upper proton permeable membrane 106, and a second alumina tube 202 was formed on the surface of the Si substrate 101. The first alumina tube 201 and the second alumina tube 202 were bonded with sealing glass.

  Finally, a DC power supply 301 and an impedance analyzer 302 were electrically connected between the lower proton permeable membrane 104 and the upper proton permeable membrane 106 using Ag paste and Au wire.

<X-ray diffraction results>
X-ray diffraction of the produced hydrogen permeable structure 100 was measured. In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lattice constants of the buffer film 103, the lower proton permeable membrane 104 (upper proton permeable membrane 106), and the electrolyte membrane 105 in the direction parallel to the first surface of the Si substrate 101 are 0.421 nm and 0.415 nm, respectively. It was 0.425 nm. The electrolyte membrane 105 had a larger lattice constant than the lower proton permeable membrane 104.

  The difference in lattice constant between the buffer membrane 103 and the lower proton permeable membrane 104 and the difference between the lattice constant between the lower proton permeable membrane 104 and the electrolyte membrane 105 were both 0.03 nm or less.

Further, compared to the Si substrate 101, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 have a large linear expansion coefficient (about 7E ^-6 K ^-1 ). Therefore, after producing the hydrogen permeable structure 100, the expansion coefficient between the Si substrate 101 having a small linear expansion coefficient and the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 having a large linear expansion coefficient. There is a difference. Due to this difference, tensile stress is applied to the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106. The lattice constants in the direction perpendicular to the first surface of the Si substrate 101 in the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are each in the direction parallel to the first surface of the Si substrate 101. It was found to be smaller and distorted to tetragonal crystals.

<Proton conductivity>
The electrical conductivity of the electrolyte membrane 105 was measured using the impedance analyzer 302. The electrical conductivity of the electrolyte membrane 105 corresponds to the proton conductivity of the electrolyte membrane 105.

The hydrogen permeable structure 100 was heated to 200 ° C. by an external heater. Thereafter, a mixed gas of Ar gas and hydrogen gas (Ar: H ₂ = 95: 5) is supplied to the upper proton permeable membrane 106 side and the Si substrate 101 side so that Ar: H ₂ = 95: 5. In the atmosphere, the electric conductivity of the electrolyte membrane 105 was measured. Table 1 shows the results.

<Hydrogen permeation performance of hydrogen permeable structure 100>
The amount of hydrogen obtained from the Si substrate 101 side was measured using a gas chromatograph. This amount of hydrogen corresponds to the hydrogen permeation performance of the hydrogen permeable structure 100.

  The hydrogen permeable structure 100 was heated to 200 ° C. using an external heater. Thereafter, hydrogen gas of 10 ml / min is supplied from the upper proton permeable membrane 106 side, and the lower proton permeable membrane 104 and the upper proton permeable membrane 106 are connected by the DC power source 301 with the lower proton permeable membrane 104 side grounded. A voltage of 2 V was applied between them (the lower proton permeable membrane 104 side was grounded). At this time, the amount of hydrogen obtained from the Si substrate 101 side was measured using a gas chromatograph. Table 1 shows the results.

<Peeling at the interface of each film>
It was confirmed whether the surface of the Si substrate 101 on which the porous portion 102 is formed, the interface between the buffer film 103, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are separated. Specifically, after measuring the amount of hydrogen obtained from the Si substrate 101, the presence or absence of cracks and the presence or absence of light interference fringes due to gaps generated at the film interface were observed using an optical microscope. When it was observed that there was a crack and when it was observed that there was a light interference fringe, it was determined that it was peeled off. When no cracks were observed and when no light interference fringes were observed, it was determined that no peeling occurred. In Example 1, it was determined that peeling was not performed. Table 1 shows the results.

(Example 2)
In Example 2, the buffer film 103 is a (ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 film having a thickness of 10 nm, a CeO ₂ film having a thickness of 30 nm, and a La _0.5 Sr _0.5 MnO ₃ film having a thickness of 10 nm. And a SrRuO ₃ film having a thickness of 50 nm was used, and the experiment was performed in the same manner as in Example 1.

<X-ray diffraction results>
In the measurement result of the X-ray diffraction, all of the SrRuO ₃ film, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 included in the buffer film 103 are very strong derived from the plane orientation of the Si substrate 101. A diffraction peak was present. That is, it was confirmed that each of the SrRuO ₃ film, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 included in the buffer film 103 is epitaxially grown (the crystal orientation is aligned).

The lattice constant of the SrRuO ₃ film in the direction parallel to the first surface of the Si substrate 101 was 0.394 nm. The lattice constants of the lower proton permeable membrane 104 (upper proton permeable membrane 106) and the electrolyte membrane 105 in the direction parallel to the first surface of the Si substrate 101 were the same as in Example 1. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 3)
In Example 3, (Ba _0.2 Ca _0.2 Zr _0.7 Y _0.3 O _2.85 ) _0.4 (SrRuO ₃ ) _0.6 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.4 Ca _0.5 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that a Zr _0.8 Y _0.2 O _2.9 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.412 nm, and the electrolyte membrane 105 was 0.425 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

Example 4
In Example 4, as a lower proton permeable membrane 104 and an upper proton permeable membrane 106, as _{(Ba 0.5 Sr 0.4 Zr 0.3 Hf} 0.3 Y 0.4 O 2.8) 0.3 (SrRuO 3) 0.7 film is formed, the electrolyte membrane 105, Ba _0.4 The experiment was performed in the same manner as in Example 1 except that a Sr _0.4 Zr _0.3 Hf _0.3 Y _0.4 O _2.8 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.408 nm, and the electrolyte membrane 105 was 0.419 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 5)
In Example 5, a (Ba _0.3 Zr _0.5 Ce _0.2 Y _0.3 O _2.85 ) _0.7 (SrRuO ₃ ) _0.3 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.7 Zr _0.5 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that a Ce _0.2 Y _0.3 O _2.85 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.410 nm, and the electrolyte membrane 105 was 0.426 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 6)
In Example 6, a (Ba _0.7 Zr _0.4 In _0.2 Ce _0.4 O _2.9 ) _0.25 (SrRuO ₃ ) _0.75 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.6 Zr _0.4 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that an In _0.2 Ce _0.4 O _2.9 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.417 nm, and the electrolyte membrane 105 was 0.429 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 7)
In Example 7, (Ba _0.6 Zr _0.4 Ga _0.1 La _0.1 Y _0.4 O _2.7 ) _0.2 (SrRuO ₃ ) _0.8 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _{0.5 is used} as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that a Zr _0.4 Ga _0.1 La _0.1 Y _0.4 O _2.7 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.415 nm, and the electrolyte membrane 105 was 0.425 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 8)
In Example 8, the composition of the lower proton permeable membrane 104 and the upper proton permeable membrane 106 is (Ba _0.3 Zr _0.3 Al _0.1 Gd _0.1 Y _0.5 O _2.65 ) _0.5 (SrRuO ₃ ) _0.5 membrane, and as the electrolyte membrane 105, The experiment was performed in the same manner as in Example 1 except that a Ba _0.95 Zr _0.3 Al _0.1 Gd _0.1 Y _0.5 O _2.65 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.412 nm, and the electrolyte membrane 105 was 0.426 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

Example 9
In Example 9, the experiment was performed in the same manner as in Example 1 except that a buffer film was formed between the Si substrate 101 and the buffer film 103.

Using a sputtering method, an MgAl ₂ O ₄ film was formed as a buffer film on the surface of the Si substrate 101 on which the porous portion 102 was formed. The Si substrate 101 disposed in the chamber of the sputtering apparatus was 750 ° C. The inside of the chamber was an Ar gas atmosphere, and the pressure was 1 Pa.

MgAl ₂ O ₄ was used as a sputtering target. A high frequency (RF) power supply was used and the input power was 50W. The formed buffer film (MgAl ₂ O ₄ film) had a thickness of 100 nm. On the buffer membrane, similarly to Example 1, the buffer membrane 103, the lower proton permeable membrane 104, the upper proton permeable membrane 106, and the electrolyte membrane 105 were sequentially formed from the bottom to the top.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned). The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 1)
In Comparative Example 1, the experiment was performed in the same manner as in Example 1 except that the Si substrate 101 used to form the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 was 500 ° C.

<X-ray diffraction results>
In the measurement results of X-ray diffraction, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are not only diffraction peaks derived from the plane orientation of the Si substrate 101 but also the plane orientation of the Si substrate 101. It had diffraction peaks with different plane orientations. All of these peaks had the same intensity. That is, it was confirmed that the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are polycrystalline.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 2)
In Comparative Example 2, the experiment was performed in the same manner as in Example 1 except that a Pd film was formed as the buffer film 103.

  A sputtering method was used to form a Pd film as the buffer film 103 on the surface of the Si substrate 101 on which the porous portion 102 was formed. The Si substrate 101 disposed in the chamber of the sputtering apparatus was 250 ° C. The inside of the chamber was an Ar gas atmosphere, and the pressure was 1 Pa.

  Pd was used as a sputtering target. A high frequency (RF) power supply was used and the input power was 20W.

<X-ray diffraction results>
In the measurement results of X-ray diffraction, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are not only diffraction peaks derived from the plane orientation of the Si substrate 101 but also the plane orientation of the Si substrate 101. It had diffraction peaks with different plane orientations. All of these peaks had the same intensity. That is, it was confirmed that the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are polycrystalline.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 3)
In Comparative Example 3, (Ba _1.1 Zr _0.8 Y _0.2 O _2.9 ) _0.5 (SrRuO ₃ ) _0.5 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _1.0 Zr _0.7 Y _0.3 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that the O _2.85 film was formed.

<X-ray diffraction results>
In the measurement results of X-ray diffraction, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are not only diffraction peaks derived from the plane orientation of the Si substrate 101 but also the plane orientation of the Si substrate 101. It had diffraction peaks with different plane orientations. All of these peaks had the same intensity. That is, it was confirmed that the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are polycrystalline.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 4)
In Comparative Example 4, a (Ba _0.3 Zr _0.8 Y _0.2 O _2.9 ) _0.8 (SrRuO ₃ ) _0.2 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.4 Zr _0.7 Y _0.3 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that an O _2.85 film was formed.

<X-ray diffraction results>
In the measurement results of X-ray diffraction, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are not only diffraction peaks derived from the plane orientation of the Si substrate 101 but also the plane orientation of the Si substrate 101. It had diffraction peaks with different plane orientations. All of these peaks had the same intensity. That is, it was confirmed that the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are polycrystalline.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 5)
In Comparative Example 5, an experiment was performed in the same manner as in Example 1 except that a (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.8 (SrRuO ₃ ) _0.2 film was formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106. It was done.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.420 nm, and the electrolyte membrane 105 was 0.425 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 6)
In Comparative Example 6, the experiment was performed in the same manner as in Example 1 except that a (Ba _0.9 Zr _0.8 Y _0.2 O _2.9 ) _0.1 (SrRuO ₃ ) _0.9 film was formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106. It was.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.401 nm, and the electrolyte membrane 105 was 0.425 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 7)
In Comparative Example 7, (Ba _0.9 Zr _0.9 Y _0.1 O _2.95 ) _0.5 (SrRuO ₃ ) _0.5 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.8 Zr _0.9 Y _0.1 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that an O _2.95 film was formed.

<X-ray diffraction results>
In the measurement result of X-ray diffraction, the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 all have very strong diffraction peaks derived from the plane orientation of the Si substrate 101. It was. That is, it was confirmed that each of the buffer film 103, the lower proton permeable film 104, the upper proton permeable film 106, and the electrolyte film 105 was epitaxially grown (the crystal orientation was aligned).

  The lower proton permeable membrane 104 and the upper proton permeable membrane 106 were 0.413 nm, and the electrolyte membrane 105 was 0.423 nm. The other results were the same as in Example 1.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 8)
In Comparative Example 8, (Ba _0.9 Zr _0.3 Y _0.7 O _2.65 ) _0.5 (SrRuO ₃ ) _0.5 film is formed as the lower proton permeable membrane 104 and the upper proton permeable membrane 106, and Ba _0.8 Zr _0.3 Y _0.7 is formed as the electrolyte membrane 105. The experiment was performed in the same manner as in Example 1 except that an O _2.65 film was formed.

<X-ray diffraction results>
In the measurement results of X-ray diffraction, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are not only diffraction peaks derived from the plane orientation of the Si substrate 101 but also the plane orientation of the Si substrate 101. It had diffraction peaks with different plane orientations. All of these peaks had the same intensity. That is, it was confirmed that the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 are polycrystalline.

<Proton conductivity, hydrogen permeation performance of the hydrogen permeable structure 100, peeling at the interface of each membrane>
As described above, the experiment was performed in the same manner as in Example 1. Table 1 shows the results.
The hydrogen permeation performance is standardized with the amount of hydrogen detected on the Si substrate 101 side in Comparative Example 2 as 1.

  Tables 2 and 3 show the compositions of the electrolyte membrane 105, the lower proton permeable membrane 104, and the upper proton permeable membrane 106 in Examples 1 to 9 and Comparative Examples 1 to 8.

  It was found that the electrolyte membranes 105 in Examples 1 to 9 have higher hydrogen permeation performance than the electrolyte membranes 105 in Comparative Examples 1 to 8. Furthermore, it was found that Examples 1 to 9 also have proton conductivity equal to or higher than that of the electrolyte membrane 105 of Comparative Examples 1 to 8.

  Examples 1 to 9 have high hydrogen permeation performance and proton conduction, and each of the Si substrate 101, the buffer film 103, the lower proton permeable film 104, the electrolyte film 105, and the upper proton permeable film 106. It was found that no peeling occurred at the interface.

  In Examples 1 to 9, compared with Comparative Examples 1 to 4 and Comparative Example 8 in which the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 were polycrystalline membranes, 20 The water tank permeability was as high as about 100 to 100 times.

In Comparative Example 5, since the amount of SrRuO ₃ contained in the lower proton permeable membrane 104 and the upper proton permeable membrane 106 was too small, the electron conductivity of the lower proton permeable membrane 104 and the upper proton permeable membrane 106 was small. The conductivity of the electrolyte membrane 105 and the hydrogen permeation performance of the hydrogen permeable structure 100 could not be measured. In Comparative Example 6, since the amount of SrRuO ₃ contained in the lower proton permeable membrane 104 and the upper proton permeable membrane 106 was too large, the lower proton permeable membrane 104 and the upper proton permeable membrane 106 did not pass hydrogen, The hydrogen permeation performance of the hydrogen permeable structure 100 could not be measured. Furthermore, in Comparative Example 8, since the amount of Y contained in the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 was too small, the lower proton permeable membrane 104, the electrolyte membrane 105, and the upper proton permeable membrane 106 were used. The amount of oxygen deficiency was insufficient, and the proton conductivity of the electrolyte membrane 105 and the hydrogen permeation performance of the hydrogen permeable structure 100 were small.

  In Examples 1 to 9, the A sites of the lower proton permeable membrane 104 and the upper proton permeable membrane 106 contain Ba. Sr and Ca are alkaline earth metals, and it is presumed that the same effect is obtained even if they are used instead of Ba. In Example 1 to Example 9, the D sites of the lower proton permeable membrane 104 and the upper proton permeable membrane 106 contain Zr. Zr and Hf, Y, La, Ce, Gd, In, Ga, and Al are elements of the same family, and it is estimated that the same effect can be obtained even if they are used instead of Zr.

  In Example 1 to Example 9, the A site of the electrolyte membrane 105 contains Ba. Sr and Ca are alkaline earth metals, and it is presumed that the same effect is obtained even if they are used instead of Ba.

  Further, D may be selected from 4A group Zr, Hf, rare earth metal Y, La, Ce, Gd, and 3B group In, Ga, Al, and the same effect is estimated.

  When a laminate having a dense interface without voids is formed, the proton permeable membrane and the electrolyte membrane are epitaxially grown, so that the bond at the interface becomes strong, and peeling at the membrane interface can be suppressed. In addition, since the proton permeable membrane and the electrolyte membrane are epitaxially grown, the disorder of the atomic arrangement at the membrane interface is reduced and the resistance to proton conduction at the membrane interface is reduced, so that proton conduction is facilitated in the vertical direction of the membrane. is there. As a result, a structure having high reliability and good hydrogen permeability can be realized.

  It should be noted that the specific embodiments or examples made in the section of the examples only clarify the technical contents of the present invention, and should not be construed in a narrow sense by limiting only to such specific examples. Various changes can be made within the spirit and scope of the present invention.

  The hydrogen permeable structure according to an example of the present disclosure has high proton conductivity and high reliability that reduces separation of the electrolyte membrane and the proton permeable membrane, and is useful for hydrogenation devices, fuel cells, steam electrolysis, and the like. is there.

DESCRIPTION OF SYMBOLS 100 Hydrogen permeable structure 101 Si substrate 102 Porous part 103 Buffer film 104 Lower proton permeable film 105 Electrolyte film 106 Upper proton permeable film 201, 202 Alumina tube 301 DC power supply 302 Impedance analyzer

Claims (6)

A Si substrate having a surface on which a porous part is formed;
A lower proton permeable membrane formed on the upper surface of the Si substrate and being a single crystal;
An electrolyte membrane that is formed on the lower proton permeable membrane and is a single crystal;
The lower proton permeable membrane has a perovskite crystal structure represented by a composition formula A1 _1-x1 (D _1-y Ru _y ) O _z1 ,
A1 is at least one element selected from Ba, Sr and Ca;
D is at least one element selected from Zr, Hf, Y, La, Ce, Gd, In, Ga and Al;
0 <x1 ≦ 0.5, 0.3 ≦ y ≦ 0.8, and z1 <3 are satisfied,
The electrolyte membrane has a perovskite crystal structure represented by a composition formula A2 _1-x2 (E _1-w G _w ) O _z2
A2 is at least one element selected from Ba, Sr and Ca;
E is at least one element selected from Zr, Hf, In, Ga and Al,
G is at least one element selected from Y, La, Ce and Gd;
0 <x2 ≦ 0.5, 0.2 ≦ w ≦ 0.6, z2 <3,
Hydrogen permeable structure.   The hydrogen permeable structure according to claim 1, wherein the lower proton permeable membrane and the electrolyte membrane both have a tetragonal crystal structure. Furthermore, an upper proton permeable membrane that is formed on the electrolyte membrane and is a single crystal is provided,
The upper proton permeable membrane has a perovskite crystal structure represented by a composition formula A1 _1-x1 (D _1-y Ru _y ) O _z1 .
A1 is at least one element selected from Ba, Sr and Ca;
D is at least one element selected from Zr, Hf, Y, La, Ce, Gd, In, Ga and Al;
Satisfy 0 <x1 ≦ 0.5, 0.3 ≦ y ≦ 0.8, and z1 <3
The hydrogen-permeable structure according to claim 1.   The hydrogen permeable structure according to claim 1, further comprising a buffer film made of an oxide between the Si substrate and the lower proton permeable film.   The hydrogen permeable structure according to claim 3, wherein the buffer film contains Mg and O.   The hydrogen permeable structure according to claim 3, wherein the buffer film contains Sr, Ru, and O.

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