JP2001189114A - Manufacturing method of transparent electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to simply manufacture a zinc-oxide-based transparent electrode comprising zinc oxide with the addition of group III elements of the periodic table like aluminum and gallium, in which the amounts of the added elements are controlled, or the concentration and kinds of the added elements are controlled in the film-thickness direction. SOLUTION: On the upper layer or the lower layer of a zinc-oxide layer, a thin-film layer containing at least one kind of element selected from group III elements of the periodic table like aluminum or gallium is formed. The group III elements in the periodic table contained in the thin film are diffused into the zinc-oxide layer. For example, after a thin-film layer containing at least one kind of element selected from the group III elements of the periodic table is formed on a substrate like a glass substrate, a zinc-oxide layer is formed on the thin-film layer. In this case, in the process of the formation of the zinc-oxide layer or after the formation of the zinc-oxide layer, the group III elements of the periodic table contained in the above-mentioned thin-film layer are diffused into the zinc-oxide layer formed by a method like heating, and a zinc-oxide-based transparent electrode is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a transparent electrode used for a photovoltaic element, a thin film transistor and the like.

[0002]

2. Description of the Related Art Conventionally, tin oxide-based materials have been widely used as transparent electrodes used as electrodes for electronic devices such as photovoltaic elements and thin film transistors. Such an electrode for an electronic device has a function of transmitting light,
And it is desired that the electric resistance is small. The tin oxide-based material is preferably used because it is excellent in transparency and electric resistance characteristics.

As an attempt to further reduce the electrical resistance of a transparent electrode material, an indium tin oxide (hereinafter, also referred to as ITO) -based material obtained by adding tin to indium oxide has been widely used. I have.

[0004] However, although the tin oxide-based transparent electrode and the indium tin oxide-based transparent electrode certainly show excellent characteristics in terms of transparency and electric resistance, they are exposed to hydrogen plasma in a manufacturing process for manufacturing a device. At this time, tin and indium have been reduced and deposited, causing a problem of deteriorating device performance. In addition, indium was said to be scarce in resources and had a problem in production cost. Therefore, in recent years, zinc oxide-based materials have been proposed and manufactured as inexpensive materials having high plasma resistance.

A transparent electrode using each of the above-mentioned materials is generally formed on a base material or a base layer, and the manufacturing method thereof is a vacuum evaporation method, a sputtering method, and a chemical vapor deposition method (hereinafter, referred to as a chemical vapor deposition method). A vapor deposition method such as a CVD method); a spray method; and a method of applying a solution containing a compound to be a precursor of each of the above-described materials to a substrate, and then converting the precursor by a method such as heating in an oxidizing atmosphere. A solution coating method or the like for forming a layer made of each material is used. Among these, the vacuum evaporation method and the sputtering method are particularly preferably used from the viewpoint of producing a high-performance transparent electrode.

A typical example of the production of a zinc oxide-based transparent electrode by such a method is described in JP-A-7-249316.
An embodiment described in Japanese Patent Application Laid-Open Publication No. H10-209,043 is known. This Example describes that a transparent electrode was manufactured in an argon atmosphere by a DC magnetron sputtering method using various targets in which gallium oxide was added to zinc oxide. More specifically, when a film containing zinc oxide having a crystal structure oriented in a specific direction and containing gallium in an amount of 0.1 to 15 atomic% with respect to zinc and having a thickness of 10 nm to 5 μm, High stability and specific resistance of 10 ^-2
It is described that a zinc oxide film having a low resistance of Ωcm or less can be manufactured.

As described above, the zinc oxide-based transparent electrode is generally manufactured by a sputtering method. At this time, in order to control the resistance of the zinc oxide film, the second electrode of the periodic table II is controlled.
A small amount of Group I element is added. Usually, as described in JP-A-7-249316, the addition of such an element is used as a sputtering target, for example, in the form of an oxide such as aluminum oxide or gallium oxide. Is performed by using zinc oxide which is uniformly dissolved so as to have a constant concentration.

However, when such a target is used to add a Group III element of the periodic table, the sputtering rates of zinc oxide, which is a main raw material, and an oxide of a Group III element of the periodic table are different. As a result, there has been a problem that the composition of the target changes with the use time of the target, and a zinc oxide electrode having a desired composition cannot be manufactured.

In some applications, it is necessary to control the concentration and type of the additive element in the thickness direction of the zinc oxide film serving as a transparent electrode. It is necessary to prepare a plurality of different targets and to perform sputtering while sequentially changing the targets, and there is a problem that the operation is complicated. In order to improve the operability by eliminating the trouble of replacing the target, a substrate rotating multi-source sputtering apparatus capable of mounting a plurality of targets having different compositions has been developed, but when such an apparatus is used, Because the substrate rotates at a constant speed,
There is a problem that the speed of obtaining the film is significantly reduced. Furthermore, it is difficult to continuously produce a transparent electrode using such an apparatus, and there is a problem that it is not suitable for production on an industrial scale.

[0010]

As described above, a zinc oxide-based transparent electrode made of zinc oxide to which a Group III element of the periodic table is added, wherein the zinc oxide-based transparent electrode in which the amount of the added element is controlled. There has been no known method for easily producing an electrode or a zinc oxide-based transparent electrode in which the concentration and type of an additive element are controlled in the film thickness direction. An object of the present invention is to provide a method for easily producing such a zinc oxide-based transparent electrode.

[0011]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems. As a result, once formed on the substrate a thin film layer containing a Group III element of the periodic table,
When a zinc oxide layer is formed on the thin film layer by a sputtering method, the base thin film layer constituting the base thin film layer in the zinc oxide layer obtained by heating the substrate at the time of sputtering is described in II.
It was found that the I-elements spread.

Further, as a result of further study based on the findings, it is possible to control the amount of the group III element of the periodic table contained in the zinc oxide layer by controlling the diffusion conditions such as the substrate heating conditions. That, the use of such a diffusion phenomenon is applicable not only to the sputtering method but also to the case where a zinc oxide layer is formed by another vapor deposition method or a solution coating method.
It has been found that a similar effect can be obtained even if a zinc oxide layer is formed first and then the thin film layer is formed and then diffusion treatment is performed, and the present invention has been completed.

That is, a first aspect of the present invention is to form a thin film layer containing at least one element selected from Group III of the periodic table on a substrate and then form a zinc oxide layer on the thin film layer. A method for producing a zinc oxide-based transparent electrode, comprising: forming the zinc oxide layer or after forming the zinc oxide layer; and forming the zinc oxide layer in the formed zinc oxide layer.
A method for producing a zinc oxide-based transparent electrode, characterized by diffusing a group III element.

Specific examples of the method for producing the zinc oxide-based transparent electrode according to the first aspect of the present invention include the following production methods.

After forming a thin film layer containing at least one element selected from Group III of the periodic table on the substrate, forming a layer substantially composed of a zinc oxide precursor on the thin film layer; A method for producing a zinc oxide-based transparent electrode in which the zinc oxide precursor is converted to zinc oxide by heating to form a zinc oxide layer, the process comprising forming the zinc oxide layer or forming the zinc oxide layer. And oxidizing the group III element contained in the thin film layer into a layer of the zinc oxide precursor or a zinc oxide layer formed by converting the zinc oxide precursor. A method for producing a zinc-based transparent electrode.

After forming a thin film layer containing at least one element selected from Group III of the periodic table on a substrate, zinc oxide is deposited on the thin film layer by heating while heating the thin film layer. A method for producing a zinc oxide-based transparent electrode for forming a zinc layer, comprising: a step of forming the zinc oxide layer or a period included in the thin film layer in the deposited zinc oxide layer after the formation of the zinc oxide layer. A method for producing a zinc oxide-based transparent electrode, characterized by diffusing a Group III element of the Table.

According to a second aspect of the present invention, after a zinc oxide layer is formed on a substrate, a thin film layer containing at least one element selected from Group III of the periodic table is formed on the zinc oxide layer. Forming a zinc oxide-based transparent electrode, and then performing a treatment of diffusing a group III element of the periodic table contained in the thin film layer into the zinc oxide layer.

According to the first and second production methods of the present invention, the diffusion conditions of the Group III element (also simply referred to as Group III element) of the periodic table during the formation of the zinc oxide layer, or the zinc oxide layer By controlling the diffusion conditions performed after the formation, the amount of the Group III element added to the zinc oxide layer can be easily controlled, and the concentration distribution of the added Group III element in the film thickness direction can be controlled. It is also possible. For example,
According to the first aspect of the present invention, the transparent electrode composed of the zinc oxide layer in which the concentration of the group III element in the zinc oxide layer decreases as going upward of the film, and the group III element is uniform in all layers. A transparent electrode composed of a zinc oxide layer that is dispersed in a layer can be easily manufactured. As a result of controlling the addition amount and the concentration distribution of the group III element, it is possible to manufacture a transparent electrode in which the resistance value, the light transmittance, the reflection and scattering state of incident light, the heat resistance, and the like are controlled. it can. Therefore, the transparent electrode manufactured by such a method is expected to also function as a coating film for light control.

A third aspect of the present invention is directed to a zinc oxide in which a Group III element of the periodic table may be diffused from a thin film layer formed thereunder formed in the manufacturing method of the first aspect of the present invention. A thin film layer comprising at least one element selected from Group III of the periodic table is further formed on the layer, and then the thin film layer, or a thin film located below the thin film layer and the zinc oxide layer A method for producing a zinc oxide-based transparent electrode, characterized by diffusing a Group III element of the periodic table contained in the layer into the zinc oxide layer.

According to the manufacturing method, since the Group III element diffuses from the upper part of the zinc oxide layer formed by the first manufacturing method of the present invention, it is possible to control the concentration distribution of the Group III element with more diversity. Can be done. For example, a Group III element diffused from above (also referred to as a secondary additive element) is made to be the same as a Group III element diffused from below (diffused in the present invention) (also referred to as a primary additive element). Thereby, a transparent electrode composed of a zinc oxide layer having a high concentration of group III elements near the lower surface and the upper surface of the zinc oxide layer and having a low concentration of group III elements in the center can be manufactured.

Further, by changing the types of the primary additive element and the secondary additive element, the concentration of the primary additive element gradually decreases from below to above, and the concentration of the secondary additive element decreases from above to below. It is also possible to manufacture a transparent electrode comprising a zinc oxide layer that has been gradually reduced. In particular, when the primary additive element is aluminum and the secondary additive element is gallium, a zinc oxide layer having characteristics of low resistance on the substrate side (lower side) and resistance to thermal oxidation on the upper side can be obtained. The transparent electrode composed of the zinc oxide layer exhibits an excellent effect in the application of processing by heating in air.

In the first to third production methods of the present invention, when the zinc oxide layer is formed by a chemical vapor deposition method such as a sputtering method, the thin film layer is formed by using the same apparatus. What is necessary is just to prepare zinc oxide and the number of kinds of group III elements to be added as target materials, and the apparatus is simplified when a plurality of elements are added.

According to a fourth aspect of the present invention, a silicon-based thin film layer that is an n-type impurity semiconductor and a silicon-based thin film layer that is a p-type impurity semiconductor are joined directly or via a silicon-based thin film layer that is an intrinsic semiconductor. In a method for manufacturing a photovoltaic element including a structure in which a zinc oxide-based transparent electrode is directly or via another layer on at least one surface of the laminated body,
A method for manufacturing a photovoltaic element, wherein a zinc oxide-based transparent electrode is manufactured by any one of the first to third manufacturing methods of the present invention.

In the manufacturing method of the present invention, since the manufacturing method of the present invention is employed as the step of forming the zinc oxide-based transparent electrode, the features of the manufacturing method of the present invention are exhibited in this step.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a manufacturing method according to the present invention, first, a specific thin film layer is formed on a substrate. Here, the substrate is not particularly limited as long as it is a material on which a thin film layer and a zinc oxide film can be formed. As a substrate that can be suitably used, quartz glass, various transparent substrates such as blue plate glass,
Single-crystal silicon, polycrystalline silicon, amorphous silicon, various metals, heat-resistant polymers, and other transparent conductors, and a laminated base material on which these materials are laminated (for example, a silicon-based thin film layer which is an n-type impurity semiconductor; A laminate in which a silicon-based thin film layer that is a p-type impurity semiconductor is bonded directly or through a silicon-based thin film layer that is an intrinsic semiconductor, or a laminate in which another thin film layer such as a metal thin film is further laminated on the laminate. Etc.).

The thin film layer formed on the substrate by the first manufacturing method of the present invention comprises a group III element (group 3 element) of the periodic table,
That is, boron, aluminum, gallium, indium,
Or at least one element selected from thallium. When these elements are incorporated into the zinc oxide layer, they become donors and lower the resistance. The thin film layer may be a thin film layer containing only one of the above Group 3 elements or a thin film layer containing two or more different elements. The thin film layer may contain an element other than the Group 3 element as long as the performance (characteristics) of the finally obtained transparent electrode is not adversely affected. Such elements include oxygen, zinc, nitrogen, carbon, and the like. However, from the viewpoint of particularly improving the characteristics of the finally obtained transparent electrode, it is preferable that the transparent electrode does not contain impurities other than Group 3 elements and oxygen.

Although the thickness of the thin film layer is not particularly limited,
From the viewpoint of light transmittance, 2 to 300 nm, particularly 5 to 100 n
m is preferred.

The method for forming the thin film layer is not particularly limited, and a known method such as a vapor deposition method, a printing method, a spraying method and the like can be employed. Among these methods, it is preferable to use an evaporation method from the viewpoint of obtaining a high-purity thin film having a controlled thickness.

In the first manufacturing method of the present invention, a zinc oxide layer is formed on the thin film layer formed as described above. The method for forming the zinc oxide layer is not particularly limited, and a vacuum evaporation method, a sputtering method, and a chemical vapor deposition method (hereinafter, referred to as
Known methods such as a vapor deposition method such as a CVD method), a spray method, and a solution coating method can be applied. In the vacuum evaporation method and the sputtering method, a zinc oxide sintered body may be used as a target, and evaporation may be performed in the same manner as in a normal method.
The method may be performed by an ordinary plasma CVD method using a source gas containing dimethyl zinc (DME) or the like. In the case of performing the solution coating method, a solution containing a zinc oxide precursor such as zinc alkoxide, or a suspension of zinc oxide fine particles is applied, and the precursor is converted into zinc oxide by baking. This can be suitably performed by incineration of a hydrocarbon component or sintering of zinc oxide fine particles. As such a suspension, there is a commercially available suspension, and it is preferable to use such a commercially available product.

Among these methods, the vacuum deposition method and the sputtering method are particularly preferably employed because a zinc oxide film having a small electric resistance can be produced.

In the first manufacturing method of the present invention, during or after the formation of the zinc oxide layer, the group III element constituting the thin film layer is diffused from the thin film layer in contact with the zinc oxide layer. When the zinc oxide layer is formed by a solution coating method,
Group 3 elements can diffuse into the precursor before conversion to zinc oxide.

The method of diffusing the Group 3 element constituting the thin film layer into the zinc oxide layer is not particularly limited, but it is preferable to perform heat treatment. That is, when the above diffusion is performed during the formation of the zinc oxide layer, the diffusion may be performed by heating the substrate and the thin film layer during the formation of the zinc oxide. The heat treatment may be performed on the stacked body.

Vacuum deposition, sputtering or CVD
When the zinc oxide layer is formed by a vapor deposition method such as the method, the substrate is heated to 50 to 600C, preferably 100 to 450C.
In general, the deposition is performed by heating to a temperature of about 50 ° C. to about 600 ° C. in the solution coating method. When a sufficient amount of a Group 3 element is not introduced only by diffusion in the process, it is preferable to perform a heat treatment after the formation of the zinc oxide layer.

The heat treatment conditions may be determined as appropriate according to the type of the constituent elements of the thin film layer, the thickness of the thin film layer, the method of forming the zinc oxide layer, the thickness of the zinc oxide layer, and the amount of the group III element to be introduced. The heating temperature is usually 50 to 600 ° C., and the heating time is about 10 to 600 minutes. As a heating method, a known method such as a method of heating with a heater embedded in a holder for installing a transparent electrode in a manufacturing process or a method of heating with an infrared lamp is used without particular limitation.

The amount of the group III element introduced by diffusion into the zinc oxide layer is not particularly limited, but the introduction amount (addition amount) of the total group III element relative to the number of zinc atoms is about 0.5 to 0.5.
Preferably, it is about 12 atomic%. If the addition amount is less than 0.5 atomic%, the resistance becomes large, so that it is difficult to use it as a conductive material. On the other hand, when the content is more than 12 atomic%, the transparency is deteriorated and the resistance is increased, so that it is difficult to achieve the purpose of use.

It should be noted that the temperature of the heat treatment may be restricted in some cases. For example, when a transparent electrode is formed on the surface of the uppermost layer of a substrate on which an element has already been formed, the heat treatment temperature is preferably set to less than 400 ° C. so as not to adversely affect the performance of the element.

The types of constituent elements of the thin film layer, the thickness of the thin film layer,
By fixing the conditions such as the method of forming the zinc oxide layer and the thickness of the zinc oxide layer, the heat treatment conditions at the time of forming the zinc oxide layer or the heat treatment conditions after the formation of the zinc oxide layer and the zinc oxide layer finally obtained. By examining the relationship between the concentration of the group 3 element and the concentration distribution in advance, by controlling the heat treatment conditions,
It is possible to control the amount of addition of the group element and its concentration distribution.

In the manufacturing method of the present invention, a zinc oxide layer is first formed on a substrate, a thin film layer made of a group III element is formed thereon, and the group III element is diffused into the underlying zinc oxide layer. You may. In addition, another thin film layer made of a Group 3 element is further formed on the zinc oxide layer in which the Group 3 element is diffused from the underlying thin film layer formed by the first manufacturing method of the present invention,
The group III element constituting the another thin film layer may be diffused into the zinc oxide layer. Furthermore, a plurality of thin film layer-zinc oxide layer units may be stacked, and the group III element constituting each thin film layer may be diffused into the zinc oxide layer above or below the thin film layer. In this case, the method of forming the thin film layer and the zinc oxide layer, and the method of diffusing the Group III element constituting the thin film layer may be performed in the same manner as in the first manufacturing method of the present invention.

Hereinafter, a method for producing a zinc oxide-based transparent electrode by a sputtering method will be described in more detail with reference to the drawings.

FIG. 1 is a schematic diagram of a typical sputtering apparatus B that can be used in the present invention. The apparatus is shown as an example and is not particularly limited. The sputtering apparatus B shown in FIG. 1 mainly includes reaction vessels 1a to 1c, vacuum pumps 9a to 9c, plasma sources 7a to 7c, and a gas supply device 5 communicating with each reaction vessel.
a to 5c. By sputtering using different targets in each reactor, for example, a thin film layer and a zinc oxide layer such as an aluminum thin film in 1a, a zinc oxide thin film in 1b, and a gallium (or gallium oxide) thin film in 1c can be formed. It has become.

In each of the reaction vessels 1a to 1c, there are provided a substrate mounting portion 2a to 2c to which substrate heaters 11a to 11c are mounted, and high-frequency application electrodes 3a to 3c to which various targets 10a to 10c can be mounted. The high-frequency applying electrodes 3a to 3c are matched with matching circuits 6a to 6c.
Are connected to the plasma generation sources 7a to 7c via the.
Further, in each of the reaction vessels 1a to 1c, argon as a sputtering gas can be supplied from gas supply ports 4a to 4c through a gas supply device (5a to 5c) having a gas flow controller or the like. Pressure regulator 8a
-8c and vacuum pumps 9a-9c can be maintained at a constant pressure lower than the atmospheric pressure. Further, gate devices 12a to 12c are provided between the respective reaction vessels, and the base material A (the substrate or the transparent conductive film in the manufacturing process) can be used without opening the reaction vessels to the atmosphere using the sample moving jig 13. Can be moved.

In order to manufacture a transparent electrode, first, a glass substrate is set on the base material installation portion 2a of the reaction vessel 1a, and the vacuum is evacuated to about 1 × 10 ^-6 Torr by a vacuum pump.
The substrate temperature is raised to a predetermined temperature of room temperature to 600 ° C., preferably 100 ° C. to 450 ° C. by energizing the heater 11a embedded in the substrate mounting portion 2a, and argon as a sputter gas is supplied to the flow controller 5a. Through the gas supply port 4a into the reaction vessel. Then, a high-frequency plasma is generated by applying a high frequency to the high-frequency application electrode 3a from the high-frequency application power supply 7a, and a thin metal layer made of aluminum is formed on the substrate by, for example, sputtering an aluminum target 10a.
The reaction pressure is appropriately set depending on the sputtering conditions, but a general reaction pressure is 0.1 mTorr.
r to 5 Torr. Especially 1mTorr-10
0 mTorr is preferred. The power output of the power supply for plasma generation is also set as appropriate according to the sputtering conditions. A general output range is about 10 W to 3 KW, and particularly preferably 50 W to 2 KW.

Thereafter, the substrate A is moved to the reaction vessel 1b, and the substrate is heated to 50 to 600 ° C., preferably 100 to 45 ° C.
Zinc oxide target 1 while heating to a predetermined temperature of 0 ° C.
Ob is sputtered to form a zinc oxide layer and to diffuse aluminum into the zinc oxide layer.

Further, after the zinc oxide layer is formed, the substrate A is moved to the reaction vessel 1c, and, for example, the gallium oxide target 10c
Is used to perform sputtering in the same manner as in the case of the reactor 1a to form a gallium thin film layer. In addition,
At this time, when the substrate is heated, gallium may diffuse into the zinc oxide layer during the formation of the thin film layer.

After the gallium thin film layer is formed in this manner, the gallium may be further diffused by heating to 100 to 600 ° C.
To form a zinc oxide layer.

The method for producing a zinc oxide-based transparent electrode of the present invention can be suitably employed as a transparent electrode forming step in the production of a photovoltaic element such as a solar cell. That is, a photovoltaic element generally used at present has a silicon-based thin film layer which is an n-type impurity semiconductor and a p-type layer (also referred to as an n-type layer).
Oxidation occurs on at least one surface of a stacked body in which a silicon-based thin film layer (also referred to as a p-layer) as a type impurity semiconductor is bonded directly or via a silicon-based thin film layer (also referred to as an i-layer) as an intrinsic semiconductor. Although the zinc-based transparent electrode includes a structure in which the transparent electrode is bonded directly or via another layer, the laminate or a laminate in which another layer such as a metal thin film layer is further laminated on the laminate, according to the present invention. By using it as a substrate in the method for manufacturing a zinc oxide-based transparent electrode, a photovoltaic element having the above structure can be manufactured.

In the method of manufacturing a photovoltaic element, the steps other than the step of forming the transparent electrode are not particularly limited, and the plasma CV used in the conventional method of manufacturing a photovoltaic element can be used.
Known methods such as a method of forming a silicon-based thin film by Method D and a method of forming a metal thin film by vapor deposition can be used without limitation.

For example, a transparent electrode is formed on a substrate such as glass or resin by the method for producing a zinc oxide-based transparent electrode of the present invention, and plasma CVD using a silane-based gas or a dopant gas is performed on the formed transparent electrode. A p-layer, an i-layer, and an n-layer are sequentially formed by a method, and then a transparent electrode is formed on the n-layer again by the method for producing a zinc oxide-based transparent electrode according to the present invention. An electromotive element can be manufactured. In addition, on a substrate such as glass, silicon, heat-resistant polymer or a metal substrate such as stainless steel,
After forming a metal electrode made of a metal such as aluminum or silver by a vapor deposition method, a transparent electrode is formed on the metal electrode by the method for producing a zinc oxide-based transparent electrode of the present invention, and then a silane-based gas or a dopant gas is formed thereon. Plasma C using
By forming a n-layer, an i-layer and a p-layer sequentially by the VD method, and finally forming a transparent electrode on the p-layer again by the method for producing a zinc oxide-based transparent electrode of the present invention, a so-called nip-type structure is obtained. A photovoltaic element having the same can also be manufactured.

The silicon-based thin film forming the n-layer, the i-layer, and the p-layer may be any of single crystal, polycrystal, and amorphous, or a mixture of polycrystal and amorphous. There may be. Further, these layers may be formed by a method other than the plasma CVD method.

[0050]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In this embodiment, the transparent electrode is shown in FIG.
Was produced using the sputtering apparatus shown in FIG.

The evaluation of the zinc oxide films obtained in the following examples and comparative examples was performed by the following methods (1) to (3).

(1) Transmittance of zinc oxide layer Visible region (400 nm to 800 nm) using a spectrophotometer
Was determined. The unit is shown in%.

(2) Resistivity of zinc oxide layer The resistivity was measured using a four-terminal resistance meter. The unit was expressed in Ω · cm.

(3) Group 3 element concentration and concentration distribution in the zinc oxide layer The concentration of the additive element in the film was measured using a secondary ion detection mass spectrometer. The additive concentration and the concentration distribution with respect to zinc were represented by atomic standard (atomic%).

It was evacuated to ⁶ Torr ^- [0055] Example 1 25mm × 25mm × 0.5mm (t ) in the glass substrate was set to a substrate holder of the sputtering device 1 of the apparatus 1 × 10. At this time, the glass substrate was heated to 300 ° C. by energizing a substrate heating heater embedded in the substrate holder. In this state, 10 sccm of argon gas was introduced into the sputtering apparatus, and the pressure in the apparatus was adjusted to 5 mTorr by a pressure regulator. After holding for about one hour so that heat was sufficiently transmitted to the surface of the glass substrate, 30 W of power was supplied to a high-frequency power application electrode provided with an aluminum target to generate argon gas plasma. Aluminum having a thickness of 300 Å was deposited on the substrate by sputtering for about 5 minutes. Thereafter, the substrate on which the aluminum was deposited was moved to the next reaction vessel equipped with the zinc oxide target using a sample moving jig without opening to the atmosphere. The substrate temperature was set to 300 ° C. by heating the substrate holder. In this state, 10 sccm of argon gas was introduced into the sputtering apparatus, and the pressure in the apparatus was adjusted to 50 mTorr by a pressure regulator. After holding for about 1 hour so that heat is sufficiently transmitted to the glass substrate surface,
A power of 50 W was supplied to a high-frequency power application electrode provided with a zinc oxide target to generate argon gas plasma. 10,000 Angstrom thick zinc oxide was deposited on the substrate by sputtering for about 30 minutes. After confirming that the sample temperature reached 100 ° C., the sample was taken out of the apparatus.

As a result of measuring the resistivity of the zinc oxide film with a resistance meter, 7 × 10 ⁻⁴ Ω · cm was obtained. Further, as a result of measuring the aluminum concentration in the zinc oxide, the concentration near the glass substrate and the vicinity thereof was about 2.5%, and the concentration near the surface layer was about 1.8%. The transmittance was 85% or more in the visible region.

Example 2 In Example 1, the temperature for heating the glass substrate was set to 450.
A zinc oxide film was formed in the same manner except that the temperature was changed to ° C. As a result, a specific resistance of 4 × 10 ⁻⁴ Ω · cm was obtained. Further, as a result of measuring the aluminum concentration in the zinc oxide, the concentration in the vicinity of contacting the glass substrate was about 2.7%, and the concentration in the vicinity of the surface layer was about 2.2%. The transmittance was 85% or more in the visible region.

Example 3 An aluminum and zinc oxide film was formed on a glass substrate in the same manner as in Example 1. Thereafter, the sample was moved to a reaction vessel in which a gallium oxide target was set by a sample moving jig without opening the sample to the atmosphere. The substrate temperature was set to 300 ° C. by heating the substrate holder. In this state, 1 argon gas was introduced into the sputtering apparatus.
0 sccm was introduced and the pressure inside the device was adjusted to 5 by a pressure regulator.
mTorr. After holding for about one hour so that heat was sufficiently transmitted to the surface of the glass substrate, 30 W of power was supplied to a high-frequency power application electrode provided with a gallium oxide target to generate argon gas plasma. Gallium oxide having a thickness of 300 Å was deposited on the substrate by sputtering for about 6 minutes. This state was maintained for about 1 hour, and then the heating of the sample was stopped. After confirming that the sample temperature had reached 100 ° C., the sample was taken out of the apparatus.

As a result of measuring the resistance of the obtained sample, 8 × 1
0 ^-4 Ω · cm was obtained. In addition, as a result of measuring the aluminum concentration and the gallium concentration in the zinc oxide, the aluminum concentration near the glass substrate was about 2.5%, and the gallium concentration near the surface layer was about 2.8%. The aluminum concentration and gallium concentration near the center of the zinc oxide film were 2% and 1.5%, respectively. The transmittance is 8 in the visible range.
It was 5% or more.

[0060]

According to the production method of the present invention, a zinc oxide-based transparent electrode made of zinc oxide to which an element of Group 3 of the periodic table is added can be produced easily and in a short time. In addition, it is possible to control the amount of the element added at that time and the concentration distribution of the added element in the film thickness direction, and it is possible to arbitrarily produce transparent electrodes in various modes depending on the application.

As described above, the availability of the raw materials to be used, the simplicity of the operation, and the variety of the transparent electrodes obtained (the concentration of the added element and the concentration distribution can be controlled).
In view of this, it can be said that this is a method for manufacturing a transparent electrode which is industrially excellent.

[Brief description of the drawings]

FIG. 1 is a schematic view of a typical sputtering apparatus that can be used when producing a transparent electrode film by the production method of the present invention.

[Explanation of symbols]

 1a to 1c: Reaction vessel 2a to 2c: Substrate installation part 3a to 3c: High frequency application electrode 4a to 4c: Gas supply port 5a to 5c: Flow rate controller 6a to 6c: Matching circuit 7a to 7c High-frequency power supply 8a to 8c Pressure regulator 9a to 9c Vacuum pump 10a to 10c Target 11a to 11c Substrate heater 12a to 12c Gate device 13: jig for moving sample A: base material B: sputtering device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/04 C23C 14/34 K // C23C 14/34 H01L 31/04 MH

Claims (4)

[Claims] 1. A zinc oxide-based transparent electrode comprising: forming a thin film layer containing at least one element selected from Group III of the periodic table on a substrate; and forming a zinc oxide layer on the thin film layer. In the manufacturing method, a step of forming the zinc oxide layer or after the formation of the zinc oxide layer, diffusing a Group III element of the periodic table contained in the thin film layer into the formed zinc oxide layer. A method for producing a zinc oxide-based transparent electrode. 2. After forming a zinc oxide layer on a substrate, a thin film layer containing at least one element selected from Group III of the periodic table is formed on the zinc oxide layer, and then the thin film layer is formed. A method for producing a zinc oxide-based transparent electrode, characterized by diffusing a Group III element of the periodic table contained in the zinc oxide layer into the zinc oxide layer. 3. A zinc oxide layer formed in the method for producing a zinc oxide-based transparent electrode according to claim 1, wherein a group III element of the periodic table may be diffused from a thin film layer located therebelow. Further forming a thin film layer containing at least one element selected from Group III of the periodic table, and then including the thin film layer, or the thin film layer and the thin film layer located below the zinc oxide layer A method for producing a zinc oxide-based transparent electrode, comprising diffusing a Group III element of the periodic table into the zinc oxide layer. 4. A laminated body in which a silicon-based thin film layer as an n-type impurity semiconductor and a silicon-based thin film layer as a p-type impurity semiconductor are joined directly or via a silicon-based thin film layer as an intrinsic semiconductor. 4. A method for manufacturing a photovoltaic device including a structure in which a zinc oxide-based transparent electrode is bonded to a surface directly or via another layer, wherein the zinc oxide-based transparent electrode is any one of claims 1 to 3. A method for manufacturing a photovoltaic element, characterized by manufacturing by the method of (1).