JPH0864216A - Oxygen ion conductor thin film and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a solid electrolyte for a solid electrolyte fuel cell (SOFC) by forming an oxygen ion conductor thin film with a substrate different from a film forming material and having uniformly distributed small holes and a required single crystal thin film stuck to the substrate. CONSTITUTION: A stabilized zirconia single crystal thin film 2 of a film forming material is stuck to a substrate 1 different from the film forming material by the CVD method or the like. Uniformly distributed multiple small holes 3 are bored on the substrate 1 to form an oxygen ion conductor thin film. Since the sintering method is not used, this thin film has large strength, low electric resistance, and high gas transmission efficiency, the deterioration of the material can be reduced, and the oxygen ion conductor thin film suitable for the solid electrolyte for the SOFC is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel oxygen ion conductor thin film which can be used in a solid oxide fuel cell, a high temperature gas phase water electrolyte material, an oxygen sensor and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Stabilized zirconia mixed with calcia and yttria is known as an oxygen ion conductor having high oxygen ion conductivity and excellent strength at high temperature,
Application research to a solid electrolyte for a solid oxide fuel cell (hereinafter referred to as SOFC) and the like has been widely promoted.

Taking a solid electrolyte for SOFC, which is important as an application of the stabilized zirconia oxygen ion conductor, as an example, in the manufacturing process, first, a stabilized ceramic zirconia polycrystalline thin plate is used by utilizing a general ceramics process. It is common to manufacture and then form electrodes such as nickel oxide or Sr-containing lanthanum-manganese composite oxide, which will become the fuel electrode and the air electrode, on both sides.

The ceramic process at that time is usually
Prepare a zirconia fine powder containing an appropriate amount of calcia or yttria, use it to make an unfired green sheet by the doctor blade method or powder pressing method, and then fire it in an electric furnace at a high temperature of 1000 ° C or higher. However, the stabilized zirconia polycrystalline thin plate obtained by such a sintering method is required to be self-supporting and have sufficient mechanical strength to withstand the battery manufacturing process. Therefore, the thickness is at least about 0.1 mm. It was necessary to

The biggest problem with this ceramic process is that only low conductivity stabilized zirconia can be obtained. SO using such stabilized zirconia as an electrolyte
For FC, the operating temperature must be increased to improve the conductivity and reduce the series resistance component of the fuel cell. Therefore, it is necessary to operate at a high temperature of about 1000 ° C. in the vicinity of the limit region where the constituent members of the fuel cell can withstand, and the series resistance component of the electrolyte portion still most deteriorates the fuel cell efficiency. In other words, in SOFC that uses a stabilized zirconia polycrystalline thin plate, the operating temperature must be raised to near the limit in order to increase the operating efficiency. However, if this is the case, the battery life is unavoidably shortened, and if the life is emphasized, it will operate. There is a problem that efficiency is reduced.

On the other hand, in order to avoid the problems in the case of using the polycrystalline thin plate obtained by the ceramics process as described above, a stabilized zirconia thin film is formed by the thin film process to reduce the conductivity and reduce the film thickness. There is also an attempt to compensate for this and reduce the series resistance component of the fuel cell. For example, a stabilized zirconia thin film is deposited on a porous alumina substrate using a plasma spraying method, a CVD method or the like, and a fuel electrode thin film and an air electrode thin film are similarly laminated to form a SOFC.
Is intended to be used for.

However, this one also has some problems as follows. First of all, in order to keep the electrode thin film and solid electrolyte thin film grown on the substrate homogeneous without causing pinholes, it is necessary that the porous alumina substrate be relatively dense and have a small pore size. However, if this is done, gas permeation through the porous alumina substrate will be hindered and high fuel cell operating efficiency will not be obtained, and if a porous alumina substrate with a sufficiently large pore size that does not cause gas permeation is used, it will be uniform with no pinholes. In order to form a thin film, it is necessary to make the film thickness sufficiently large, which also lowers the fuel cell operating efficiency.

The second problem is that the stabilized zirconia thin film formed on the porous alumina substrate is polycrystalline. Oxygen ions move in the stabilized zirconia thin film during the operation of the fuel cell, and such a mass transfer phenomenon belongs to the category of a phenomenon called atomic migration, which inevitably causes deformation and destruction of the material.
In the example of the destruction phenomenon of the IC aluminum wiring (this belongs to the category of the phenomenon called electromigration because it is due to the movement of conduction electrons), it is known that the material destruction progresses from the grain boundary, but it is stable during the operation of the fuel cell. It can be fully expected that material deformation and destruction will proceed from grain boundaries due to atomic migration even in the case of thin film zirconia thin film. Such material destruction of stabilized zirconia thin film becomes more serious as the film thickness becomes smaller, and thin film type SOFC can be realized. Was a major limiting factor.

[0009]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the conventional oxygen ion conductor thin film, reduces electrical resistance, enhances gas permeation efficiency, and can reduce material deterioration. It was made for the purpose of providing an ionic conductor thin film.

[0010]

Means for Solving the Problems As a result of intensive studies to develop an oxygen ion conductor thin film having the above-mentioned preferable characteristics, the present inventors have used stabilized zirconia as a film-forming material and used it as a substrate. Using a heterogeneous substrate made of a material different from this film-forming material, stabilized zirconia of the film-forming material is vapor-deposited on the substrate to form a single crystal thin film. It was found that the object can be achieved by opening the opening, and the present invention has been completed based on this finding.

That is, the present invention provides an oxygen ion conductor thin film comprising a heterogeneous substrate having a large number of uniformly distributed small openings and a stabilized zirconia single crystal thin film deposited thereon.
Alternatively, a heterogeneous substrate having a large number of uniformly distributed small openings, and a stabilized zirconia single crystal thin film deposited thereon,
Oxygen ion conductor thin film consisting of one electrode film deposited on the stabilized zirconia single crystal thin film and the other electrode film deposited on the surface opposite to the electrode film surface, or uniformly distributed Oxygen consisting of a heterogeneous substrate having a large number of small openings, a stabilized zirconia single crystal thin film deposited on one of the electrode films via one electrode film, and the other electrode film deposited on the stabilized zirconia single crystal film. An ionic conductor thin film is provided.

In the oxygen ion conductor thin film of the present invention, a single crystal thin film is formed by performing vapor phase growth of stabilized zirconia on a heterogeneous substrate, and then a large number of openings are uniformly distributed on the heterogeneous substrate. Opening or vapor-depositing stabilized zirconia on a heterogeneous substrate to form a single-crystal thin film, and then forming a large number of openings uniformly on the heterogeneous substrate. After performing the step of forming the electrode of (1) and (2) in an arbitrary order, the other electrode is formed on the side of the different substrate, or the vapor phase growth and the stabilized zirconia of one electrode forming substance are formed on the different substrate. The step of forming a single crystal thin film by sequentially performing the vapor phase growth of each of the above, and then the step of uniformly distributing a large number of openings in the different substrate and the step of forming the other electrode on the single crystal thin film are optional. In order It can be produced by the.

In the present invention, the stabilized zirconia single crystal thin film can be formed by growing stabilized zirconia from the vapor phase on a different substrate or on an electrode film formed as described below in some cases, One of the electrode films, which is interposed between it and the heterogeneous substrate in some cases, can be formed on the heterogeneous substrate by growing the electrode-forming substance from the vapor phase.

As the vapor phase growth method, a conventionally known thin film forming method, for example, an evaporation method such as an electron beam evaporation method, a sputtering method, a CVD method such as a plasma CVD method, or a laser ablation method can be applied. .

In the present invention, a heterogeneous substrate made of a material different from that of the stabilized zirconia is used as the heterogeneous substrate.
Silicon can be used as a material for the different type of substrate.

In the present invention, the case where a silicon substrate is used as a different substrate and a stabilized zirconia single crystal thin film is formed on the substrate will be described in more detail. That is,
As a recent attempt to combine semiconductor electronics and superconducting electronics, it is known to produce high-temperature superconducting thin films on silicon substrates, and single-crystal-stabilized zirconia thin films have been investigated as buffer films in such cases. As a single crystal thin film obtained by heteroepitaxially growing a stabilized zirconia thin film on a substrate at a substrate temperature of about 600 ° C. or higher, a wide composition range (for example, in the case of yttria-stabilized zirconia (Y ₂ O ₃ ) _{X / 2} ) In the composition formula (ZrO ₂ ) _1-X , it has been revealed that the stabilized zirconia having a tetragonal structure is obtained when 0.05 <x <0.3,
This can also be applied to the present invention.

Further, the production of the epitaxially stabilized zirconia thin film on the silicon substrate is carried out by the laser ablation method [[1] D. K. Fork, D.D. B. Fenne
r, G. A. N. Connel, J.M. M. Phil
ips, and T.S. H. Geballe, App
l. Phys. Lett. , Vol. 57, p. 113
7 (1990); [2] P. Tiwari, S .; M.
Kanetkar, S .; Sharan, and J.M.
Narayan, Appl. Phys. Lett. , V
ol. 57, p. 1578 (1990)], plasma C
VD method [H. Holzschuh, and H.M. Suh
r, Appl. Phys. Lett. , Vol. 59,
p. 470 (1991)], electron beam evaporation method [A. B
ardal, M .; Zwerger, O .; Eibl, J .;
Wecker, and Th. Matthee, App
l. Phys. Lett. , Vol. 61, p. 124
3 (1992)] and the like.

The surface of the silicon substrate is usually covered with a natural oxide film (SiO ₂ ) having an amorphous structure, and it is necessary to remove the natural oxide film in order to realize heteroepitaxial growth of a stabilized zirconia thin film. Generally, the natural oxide film is removed by immersing it in a 5 to 10% aqueous solution of hydrofluoric acid or by annealing in a vacuum apparatus at high temperature and high vacuum immediately before thin film growth. A single crystal film cannot be obtained unless the natural oxide film is removed sufficiently or the thin film forming conditions are not optimized, resulting in a randomly oriented polycrystalline film, or even if a preferential orientation is observed, a complete single crystal film is obtained. It doesn't. Under sufficiently optimized conditions, a stabilized zirconia (100) oriented film is grown on a silicon (100) oriented substrate, and a stabilized zirconia (111) oriented film is grown on a silicon (111) oriented substrate. Can be made.

Next, in the present invention, it is necessary to form a large number of small openings so as to be uniformly distributed in the different type substrate on which the stabilized zirconia single crystal thin film is deposited. There are no particular restrictions on how to form an opening in the different type substrate, but a wet etching method or the like is used, for example. First of all, regarding the wet etching method, since 1970, the anisotropic etching technology of silicon has progressed, opening the way to use silicon as a structural material capable of microfabrication as well as electronic materials, and various sensors and sensors have been used so far. Nozzles for inkjet printers have been developed [[1] E. Bassou
s, IEEE Trans. Electron Dev
ices, ED-25, 1178 (1978); [2]
K. E. Petersen, Proceedings
of the IEEE, vol. 70, p. 420
(1982)].

Various silicon etching solutions used in the etching method are an isotropic etching solution whose etching rate is constant regardless of the silicon plane orientation and an anisotropic etching solution whose etching rate largely depends on the silicon plane orientation. It can be roughly divided. As an anisotropic etching solution, a system in which isopropyl alcohol is added to a potassium hydroxide or sodium hydroxide aqueous solution as needed, or a system consisting of pyrocatechol, ethylenediamine and water is typical. These anisotropic etchants are silicon (100)
The etching rate with respect to the plane is extremely anisotropic such as several tens to several hundred times higher than the etching rate with respect to the (111) plane, and the silicon substrate is melted so that the (111) plane with the slowest etching rate remains on the surface. Occur. Also,
A film can be easily formed on silicon by a method such as thermal oxidation or CVD, and the etching rate for a silicon oxide film or a silicon nitride film that easily forms a pattern by photolithography technology is several orders of magnitude lower, and these films are used as masks. By doing so, the silicon substrate can be etched in a desired pattern.

The stabilized zirconia formed on a silicon substrate in the present invention is very stable against any of the above anisotropic etching solutions (potassium hydroxide / isopropanol type or ethylenediamine-pyrocatechol type). Therefore, a free-standing film of a stabilized zirconia thin film is left at the site where the silicon substrate is removed by etching.

To prepare a single cell for a solid oxide fuel cell using the stabilized zirconia self-supporting thin film having the silicon substrate, which is partially dissolved and removed by etching, as a support, the thin film of the thin film is prepared. It is efficient to make the anode on one side and the cathode on the other side. The production of these electrodes is performed by laminating the materials acting as these electrodes on the respective surfaces of the thin film in a thin film shape. Generally, the anode has La _1-x Sr _x MnO ₃ (x = 0.
_{05~0.4), La 1-y Sr} y CoO 3 (y = 0~0.
4) and other perovskite materials such as Ni for the cathode,
Materials such as Ni / ZrO ₂ cermet, CeO ₂ and Pt are used.

FIG. 1 shows a schematic view of the manufacturing process of one example of the oxygen ion conductor thin film of the present invention and one example of SOFC using it.

That is, first, on one surface of the single crystal silicon substrate 1, a CeO ₂ fuel electrode, a yttria-stabilized zirconia (hereinafter referred to as YSZ) solid electrolyte, an Sr-containing lanthanum-manganese composite oxide ( Hereinafter, air electrodes (abbreviated as LaMnO ₃ : Sr) are sequentially laminated in the form of thin films to form an anode / stabilized zirconia single crystal thin film / cathode laminated film 2 [(a) and (b) of FIG. 1]. Then, both surfaces of the silicon substrate are coated with an oxide film (for example, 5000 Å in thickness) by atmospheric pressure CVD, and then a pattern as shown in FIG. 2 is formed on the back surface of the silicon substrate by photolithography. Then
The back surface of the substrate was dipped in a hydrofluoric acid solution to dissolve and remove only the oxide film at the portion corresponding to the white background portion in FIG. 2, and the photoresist was removed by ashing. Then, the silicon substrate was cleaned with an ethylenediamine-pyrocatechol-water system. By immersing the silicon substrate in an anisotropic etching solution for about 10 hours, as shown in FIG. 1 (c), the opening 3 is opened by partially removing the silicon substrate by etching at a portion corresponding to the white background portion. Further, it is immersed in hydrofluoric acid to remove the protective oxide film. In this way, a free-standing oxygen ion conductor thin film can be produced corresponding to the small openings uniformly distributed on the substrate.

Next, the oxygen ion conductor thin film is subjected to SOF.
A stack type fuel cell is manufactured by using as a C single cell. The separator 4 used at that time is manufactured by processing a silicon substrate as shown in FIG. Then, a phosphosilicate glass (phosphos) glass is formed on the upper peripheral portion of the silicon substrate of the unit cell shown in FIG.
ilicate glass) (hereinafter referred to as PSG)
A plurality of unit cells provided with the adhesive peripheral part shown in FIG. 1D and a plurality of separators 4 shown in FIG. ) As shown in FIG. 3), and the terminal separators are used also for both end separators.

Conductive adhesion between the lower portion of the unit cell and the upper portion of the separator shown in FIGS. 1D and 1E is carried out by immersing the silicon surface of the connecting surface in dilute hydrofluoric acid to perform hydrophobic treatment. ,
This is performed by crimping and allowing electrical conduction [K. Ljungberg, A .; Soderbor
g, S. Bengtsson, and A.M. Jauhi
ainen, J .; Electrochem. Soc. ，
vol. 141, p. 562 (1994)]. Insulating adhesion between the adhesive peripheral part of the upper part of the unit cell and the lower part of the separator is performed by pressure bonding at high temperature [IEEE
Trans. Electron Devices, ED
-25 (1978)]. Further, the central portion of the upper part of the unit cell and the lower part of the separator are stacked so that the uppermost surface of the unit cell, the anode thin film and the lower part of the separator are electrically connected. This can be automatically achieved by physical contact by performing insulating adhesion between the adhesive peripheral part of the upper part of the cell and the lower part of the separator, but to obtain more reliable electrical conduction, the anode of the lower part of the separator can be obtained. It is preferable to apply a conductive paste such as a silver paste in advance to the contact portion with.

In this manner, the lower portion of the unit cell and the upper portion of the separator are laminated and electrically connected with each other with low interface resistance, and the lower portion of the separator and the silicon portion around the upper portion of the unit cell are electrically insulated, and A desired stack type solid oxide fuel cell can be manufactured in which a lower portion of the separator in the central portion and an uppermost anode of the unit cell are electrically connected at a low electric resistance value.

[0028]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 Resistivity in which phosphorus is mixed 0.001 to 0.002 Ωcm
As the (100) -oriented single crystal silicon substrate (4 inch diameter, thickness 0.35 mm), one whose both surfaces were mirror-polished was used, and each side was made to be the (110) direction with a dicing saw. It was cut into a 5 cm square. This square was RCA washed [W. Out of Kern 1, RCA Re
view, p. 187 (1970)], that is, 90 ° C.
Water kept at: hydrogen peroxide: ammonium hydroxide = 5:
After soaking in a mixed solution of 1: 0.05 for 10 minutes, soak in 5% hydrofluoric acid solution for 1 minute and pure water for 1 minute, and then take it out, then dry with nitrogen gas injection and immediately after ultrahigh vacuum specifications , Was loaded into a multi-target sputtering system. The film formation surface of the square silicon substrate housed in the substrate holder of the device was covered with an Inconel mask so that the peripheral portion was not film-formed. The film forming area was set to be a 4 cm square portion in the central portion of the square substrate.

With the substrate temperature kept at room temperature, the substrate was evacuated to the 10 ⁻⁷ torr level, and then the substrate temperature was raised to 850 ° C. using a radiation heater at a heating rate of 5 ° C./min. 850 ° C
The vacuum degree at the time of arrival was 1.5 × 10 ⁻⁶ Torr. The substrate holder was moved onto a CeO ₂ sintering target with a diameter of 10 cm, the shutter was closed to prevent film formation on the substrate at the beginning of discharge, pure argon gas was introduced up to 10 mTorr, and 100 W of 13.56 MHz high frequency power was introduced. Then, the discharge was started. After pre-discharge for 5 minutes, the shutter was opened to form a film for 30 seconds, the shutter was closed, and then the discharge was stopped. Then, the argon gas partial pressure 270
Argon gas and oxygen gas were introduced so as to have a millitorr, a partial pressure of oxygen gas of 30 millitorr, and a total reaction gas pressure of 300 millitorr, and high-frequency power of 300 W was introduced to start discharge. After preliminary discharge for 5 minutes, the shutter was opened, and after film formation for 20 minutes, the shutter was closed to terminate the discharge. In this way, the (110) plane orientation C with a film thickness of about 3000Å
An eO ₂ film was grown.

Next, argon gas partial pressure 270 mTorr, oxygen gas partial pressure 30 mTorr, total reaction gas pressure 30
The reaction gas pressure of 0 mTorr was not changed, the substrate temperature was lowered to 800 ° C., and the substrate holder of 10 cm diameter was used.
Stabilized zirconia with 10 mol% yttria added (hereinafter 1
After moving to a sintered body target (referred to as 0YSZ) and applying high-frequency power of 300 W to the target to start discharge,
After preliminary discharge for 5 minutes, the shutter was opened, and after film formation for 3 hours and 30 minutes, the shutter was closed to terminate the discharge. Thus, the (110) -oriented 10YS on the CeO ₂ film is obtained.
The Z thin film was grown to about 2 μm.

Next, the argon gas partial pressure is 270 mTorr, the oxygen gas partial pressure is 30 mTorr, and the total reaction gas pressure is 30.
0 millitorr is not changed, the substrate temperature is lowered to 500 ° C., the substrate holder is set to a diameter of La _0.8 Sr _{0.2 of} 10 cm.
The MnO ₃ sintered body is moved onto a target, high frequency power of 300 W is applied to the target to start discharge, and after 5 minutes of preliminary discharge, the shutter is opened and after 30 minutes of film formation,
By closing the shutter and ending the discharge, a polycrystalline La _0.8 Sr _0.2 MnO ₃ film having a film thickness of about 5000Å was grown. Then, the reaction gas atmosphere was cooled to room temperature at a rate of 10 ° C./min, and then taken out from the sputtering device.
In this way, single crystal C is sequentially formed on one surface of the silicon substrate.
eO ₂ film, single crystal YSZ film, polycrystalline La _0.8 Sr _0.2 Mn
The O ₃ film was laminated.

Next, a normal pressure C is applied to both surfaces of the silicon substrate.
The PSG film of about 5000 Å thickness by VD method (P ₂ O ₅ concentration of about 10
%), And then the back surface of the silicon substrate (10YS
The pattern showing the uniform distribution state shown in FIG. 2 is transferred to the back surface of the surface on which the Z film and the like are laminated) by the photolithography method, and only the transfer part corresponding to the white part in FIG. It was removed by the immersion treatment of. After the photoresist is removed by ashing, the silicon substrate is kept at about 60 ° C. in an anisotropic etchant of ethylenediamine-pyrocatechol-water (weight ratio 8: 1: 1).
After soaking for 0 hour, as shown in FIG. 1 (c), the silicon substrate is etched and removed in accordance with the above pattern, and uniformly distributed small openings are formed so that the laminated thin film becomes partially free-standing. . Then, the silicon substrate was immersed in a hydrofluoric acid-based etching solution to remove the protective PSG film. Through the above steps, the oxygen ion conductor thin film was produced.

In order to use this oxygen ion conductor thin film as a single cell for SOFC and stack it as a fuel cell stack, a separator shown in FIG. 3 is prepared separately. As the material, as in the fuel cell electrode substrate, a phosphorus-doped double-sided mirror-polished (100) oriented single crystal silicon substrate (4 inch diameter, thickness about 5 mm) having a resistivity of 0.001 to 0.002 Ωcm was used. With a wire saw,
It was cut into a square shape of 5 cm square so as to be oriented in the 10) direction, and then a gas passage portion was cut to a depth of 2 mm on both surfaces of the separator using a dicing saw. One fuel cell electrode substrate and two separators (hereinafter referred to as separator A and separator B) were prepared, and a unit cell was prepared as described below, and its performance was evaluated.

First, a PSG film having a thickness of about 4 μm was formed by an atmospheric pressure CVD method only on the outer edge portion of the surface of the fuel cell electrode substrate having a width of about 5 mm. Next, the lower part of the fuel cell electrode substrate and the upper part of the separator A were immersed in dilute hydrofluoric acid for about 1 minute to remove the oxide film to make the surface hydrophobic, and immediately both surfaces were brought into contact at room temperature for adhesion. Next, the separator B is placed on the fuel cell electrode substrate, and with the weight of about 2 kg made of quartz placed thereon, annealing is performed in an electric furnace at 1000 ° C. for about 30 minutes in an argon atmosphere to obtain two contact surfaces. Was completely bonded. Through the above processing, the fuel cell electrode substrate and the separator A were bonded while maintaining electrical continuity, and the fuel cell electrode substrate and the separator B were bonded in an electrically insulated state. However, the anode film on the outermost surface of the fuel cell electrode substrate and the separator B are in physical contact with each other and electrically connected.

In this way, a cross-flow type SOFC cell having separator A as the anode and separator B as the cathode was obtained. The SOFC unit cell was installed in an electric furnace and subjected to a power generation test at 700 ° C. using pure oxygen and pure hydrogen as raw material gases. As a result, open electromotive force 1.
A maximum output of 05 V and a maximum output of 0.4 W / cm ² was obtained.

Example 2 The same silicon substrate as in Example 1 was used, processed and treated in the same manner as in Example 1, and loaded into a multiple target sputtering apparatus. The film formation surface of the square silicon substrate housed in the substrate holder of the device was covered with an Inconel mask so that the peripheral portion was not film-formed. The film forming area was set to be a 4 cm square portion in the central portion of the square substrate.

With the substrate temperature kept at room temperature, the substrate was evacuated to the 10 ⁻⁷ torr range, and then the substrate temperature was raised to 800 ° C. using a radiant heater at a heating rate of 5 ° C./min. 800 ° C
The vacuum degree at the time of arrival was 1.2 × 10 ⁻⁶ Torr.

The substrate holder is moved onto a 10YSZ sintered compact target having a diameter of 10 cm, a shutter for not forming a film on the substrate is closed, pure argon gas is introduced up to 10 mTorr, and a high frequency power of 13.56 MHz 100 W.
Was charged to start the discharge. After preliminary discharge for 5 minutes, the shutter was opened, film formation was performed for 30 seconds, and the shutter was closed to stop the discharge. Then, the argon gas partial pressure 270
Argon gas and oxygen gas were introduced so as to have a millitorr, a partial pressure of oxygen gas of 30 millitorr, and a total reaction gas pressure of 300 millitorr, and high-frequency power of 300 W was introduced to start discharge. After preliminary discharge for 5 minutes, the shutter was opened, and after film formation for 3 hours and 30 minutes, the shutter was closed to terminate the discharge. Thus, a (100) -oriented 10YSZ thin film having a thickness of about 2 μm was formed on the silicon substrate.

Next, the argon gas partial pressure is 270 mTorr, the oxygen gas partial pressure is 30 mTorr, and the total reaction gas pressure is 30.
The reaction gas pressure of 0 mTorr was not changed, the substrate temperature was lowered to 500 ° C., and the substrate holder of 10 cm diameter was used.
La _0.8 Sr _0.2 MnO ₃ sintered body is moved onto a target, high-frequency power of 300 W is applied to the target to start discharge, and after 5 minutes of preliminary discharge, the shutter is opened.
After the film formation for 0 minutes, the shutter was closed to terminate the discharge. Polycrystalline La _{0. 8} of this way, the film thickness of about 5000Å
A Sr _0.2 MnO ₃ film was grown. Then, the reaction gas atmosphere was cooled to room temperature at a rate of 10 ° C./min, and then taken out from the sputtering device. In this manner, sequentially monocrystalline YSZ film on one side of the silicon substrate, polycrystalline La _{0. 8} Sr _0.2
The MnO ₃ film was laminated.

Next, as in Example 1, a state similar to that of FIG. 1C was realized by photolithography, anisotropic silicon etching, and the like. Then, on the back surface of the substrate, a deposition source metal Ni, an oxygen partial pressure of 1 mTorr as a deposition atmosphere, and a substrate temperature of about 5 at room temperature by electron beam evaporation.
A nickel oxide film having a thickness of 000Å was formed. In that case,
Similar to the case of depositing a YSZ film or the like, the peripheral portion of the substrate was covered with a metal mask so that only a square surface of about 4 cm × 4 cm in the central portion was deposited.

Next, the same separator as in Example 1 was prepared and laminated to prepare a cross-flow type SOFC cell consisting of two separator plates and one fuel cell electrode substrate, and in the same manner as in Example 1. The performance was evaluated by a power generation test. As a result, an open electromotive force of 1.08 V and a maximum output of 0.6 W / cm ² were obtained.

[0043]

EFFECTS OF THE INVENTION The oxygen ion conductor thin film of the present invention can be made extremely thin by about 3 digits from 1 mm to 2 μm, which was conventionally about 0.1 mm, so that the electric resistance is reduced,
The gas permeation efficiency is increased, the mass transfer of the constituent components is reduced, and the material deterioration can be suppressed. Therefore, the oxygen ion conductor thin film of the present invention is suitably used as an oxygen sensor, a vapor-phase water electrolytic material, particularly a material for a solid oxide fuel cell.

[Brief description of drawings]

FIG. 1 is an example of an oxygen ion conductor thin film of the present invention and an SOFC using the thin film solid electrolyte with an electrode.
The manufacturing process schematic of an example.

FIG. 2 is a patterning diagram of a silicon substrate.

FIG. 3 is a schematic view of a separator.

[Explanation of symbols]

1 Silicon Substrate 2 Anode / Stabilized Zirconia Single Crystal Thin Film / Cathode Laminated Film 3 Opening 4 Separator 5 PSG (phosphosilicate glass) Film

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01B 1/06 A H01M 8/12 9444-4K // C09K 3/00 C

Claims (6)

[Claims] 1. An oxygen ion conductor thin film comprising a heterogeneous substrate having a large number of uniformly distributed small openings, and a stabilized zirconia single crystal thin film deposited thereon. 2. A heterogeneous substrate having a large number of uniformly distributed small openings, a stabilized zirconia single crystal thin film deposited thereon, and one electrode film deposited on the stabilized zirconia single crystal thin film. An oxygen ion conductor thin film comprising the other electrode film deposited on the surface opposite to the electrode film surface. 3. A heterogeneous substrate having a large number of uniformly distributed small openings, a stabilized zirconia single crystal thin film deposited via one electrode film thereof, and a stabilized zirconia single crystal thin film deposited thereon. Oxygen ion conductor thin film composed of the other electrode film formed. 4. A single crystal thin film is formed on a heterogeneous substrate by vapor phase growth of stabilized zirconia, and then a large number of openings are formed in the heterogeneous substrate so as to be uniformly distributed. 1. The method for producing an oxygen ion conductor thin film according to 1. 5. A step of vapor-depositing stabilized zirconia on a heterogeneous substrate to form a single crystal thin film, and then forming a large number of openings uniformly on the heterogeneous substrate, and a step of forming the single crystal thin film on the single crystal thin film. The method for producing an oxygen ion conductor thin film according to claim 2, wherein the step of forming one electrode is performed in an arbitrary order, and then the other electrode is formed on the different substrate side. 6. A single crystal thin film is formed on a heterogeneous substrate by sequentially performing vapor phase growth of one electrode-forming substance and vapor phase growth of stabilized zirconia, respectively, and then forming a large number of openings on the heterogeneous substrate uniformly. 4. The method for producing an oxygen ion conductor thin film according to claim 3, wherein the step of distributing the oxygen ion conductor thin film and the step of forming the other electrode on the single crystal thin film are performed in an arbitrary order.