JP5087605B2 - Indium oxide-zinc oxide-magnesium oxide sputtering target and transparent conductive film - Google Patents

Description

  The present invention relates to an electrode substrate for driving a liquid crystal and an electrode substrate for EL, and more particularly to a transparent conductive film constituting a transparent electrode used in these electrode substrates. Moreover, this invention relates to the sputtering target used in order to manufacture this transparent conductive film.

Conventionally, materials doped with Sn have been studied as sputtering targets for transparent conductive films. In particular, ITO (Indium Tin Oxide) is widely used.
However, in the case of ITO, it is necessary to crystallize in order to reduce its specific resistance. Therefore, it is necessary to form a film at a high temperature or to perform a predetermined heat treatment after the film formation.

  Also, when etching crystallized ITO film, aqua regia (mixed solution of nitric acid and hydrochloric acid), which is a strong acid, is used as an etchant, but the occurrence of problems due to the use of strong acid is a problem. There is. That is, in a liquid crystal display device using a TFT (Thin Film Transistor) or the like as a constituent element, a metal thin line may be used as a gate line or source / drain line (or electrode). In this case, there has been a problem that these wiring materials are disconnected or thinned by aqua regia during etching of the ITO film.

  Thus, a method has been proposed in which amorphous ITO is formed by allowing hydrogen or water to be present in the sputtering gas during film formation, and the formed amorphous ITO is etched with a weak acid. However, since ITO itself is crystalline, when etching is performed with a weak acid, there may be a problem that an etching residue is generated. In addition, if hydrogen or water is scattered in the sputtering gas during film formation, protrusions called nodules are generated on the ITO sputtering target, which may cause abnormal discharge.

On the other hand, the following patent documents are disclosed as an example of a patent relating to a sputtering target, a conductive material, and a transparent conductive film to which Zn is added as an additive metal other than Sn generally added to the transparent conductive film.
For example, Patent Document 1 below discloses a target containing a hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (m = 2 to 20), which contains In and Zn as main components. . According to this target, it is possible to obtain a transparent conductive film that is more excellent in moisture resistance than the ITO film and has the same conductivity and light transmittance as the ITO film.

  Further, in Patent Document 2 below, for driving a liquid crystal, the value of Zn / (Zn + In), which is an atomic ratio between zinc element and indium element in an amorphous oxide, is 0.2 to less than 0.9. A color filter for a liquid crystal display provided with a transparent electrode, wherein the color filter for a liquid crystal display is less likely to cause cracks or peeling on the transparent electrode for driving the liquid crystal.

  Patent Document 3 listed below is a conductive transparent substrate containing In and Zn and having a value of In / (In + Zn) of 0.8 to 0.9, which has thermal characteristics of etching characteristics and specific resistance. A conductive transparent substrate having excellent stability is disclosed.

  Furthermore, among these disclosed Patent Documents 1 to 3, a target free from nodules can be obtained, and a transparent conductive film having excellent etching properties and a specific resistance equivalent to that of ITO can be obtained. There is also a patent document in which is shown.

Japanese Patent Laid-Open No. 06-234565 Japanese Patent Laid-Open No. 07-120612 JP 07-235219 A Japanese Patent Laid-Open No. 08-264022

  However, in the amorphous transparent conductive film, the band gap does not appear clearly, that is, the band gap is not so large, and thus there may be a problem that the light transmittance is reduced in the short wavelength side, particularly in the 400 to 450 nm region. there were.

  On the other hand, in the said patent document 4, the refractive index can be controlled and the highly transparent transparent conductive film is manufactured by adjusting the composition of a pseudo ternary system oxide. However, there is a problem that the sputtering target used for forming the transparent conductive film has a low conductivity and it is difficult to perform sputtering, and the formed transparent conductive film is crystalline, so that the etching property is not so high. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a target that does not generate nodules during sputtering. Another object of the present invention is to provide an amorphous transparent conductive film having excellent etching properties and particularly excellent transparency in the 400 to 450 nm region (having high light transmittance in the 400 to 450 nm region). It is to be.

Invention of Sputtering Target (1) Therefore, in order to solve the above problems, the present invention is a sputtering target comprising indium oxide, zinc oxide, and magnesium oxide.
By further adding magnesium oxide to a sputtering target composed of indium oxide and zinc oxide, generation of nodules generated during sputtering can be more effectively suppressed, and a target with less abnormal discharge can be obtained.

(2) Further, in the present invention, when a crystal peak obtained by X-ray diffraction is observed in a sputtering target containing indium oxide, zinc oxide, and magnesium oxide, the crystal peak is indium oxide and oxidized. A sputtering target comprising a peak derived from a hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m composed of zinc and In ₂ MgO ₄ composed of indium oxide and magnesium oxide. is there. Here, m is an integer of 3-20.

As a result of measuring the surface of the sputtering target by X-ray diffraction, when the obtained crystal peak is observed, this crystal peak includes a peak derived from a predetermined hexagonal layered compound and In ₂ MgO _4. It is essential. Here, the predetermined hexagonal layered compound is a hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (where m is an integer of 3 to 20) composed of indium oxide and zinc oxide. It is a compound. The In ₂ MgO ₄ is composed of indium oxide and magnesium oxide.

Specific examples of the hexagonal layered compound composed of indium oxide and zinc oxide include In ₂ Zn ₃ O ₆ , In ₂ Zn ₄ O ₇ , In ₂ Zn ₅ O ₈ , and the general formula is , In ₂ O ₃ (ZnO) _m (where m is an integer of 3 to 20). The size of crystal grains of these composite oxides by mapping with EPMA (Electron Probe Microanalysis: X-ray microanalyzer) is preferably 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less.

When the sputtering target does not contain the hexagonal compound composed of indium oxide and zinc oxide, In ₂ MgO _4, or the like, the bulk resistance of the sputtering target may exceed 10 mΩcm. Thus, when the bulk resistance exceeds 10 mΩcm, abnormal discharge may occur during sputtering or the sputtering target may break.

(3) Further, the present invention is sputtering according to (1), which comprises a hexagonal layered compound made of indium oxide and zinc oxide, and an In ₂ MgO ₄ consisting of indium oxide and magnesium oxide, a Is the target.

  (4) Moreover, this invention is [In] / ([In] + [Zn] + [Mg]) = 0.74-0.94, [Zn] / ([In] + [Zn] + [Mg]) = 0.05 to 0.25, and [Mg] / ([In] + [Zn] + [Mg]) = 0.01 to 0.20. ) To (3). Here, [In] represents the number of indium atoms per unit volume, [Zn] represents the number of zinc atoms per unit volume, and [Mg] represents the number of magnesium atoms per unit volume. .

Composition of indium In the sputtering target of the present invention, [In] / ([In] + [Zn] + [Mg]) = 0.74 to 0.94. When the value of [In] / ([In] + [Zn] + [Mg]) is less than 0.74, the bulk resistance of the sputtering target becomes too high, or the transparent conductive film formed Specific resistance may increase. On the other hand, when the value of [In] / ([In] + [Zn] + [Mg]) is more than 0.94, the specific resistance of the formed transparent conductive film increases or the transparent conductive The film may crystallize and generate residues during etching.

Composition of zinc In the sputtering target of the present invention, [Zn] / ([In] + [Zn] + [Mg]) = 0.05 to 0.25. When the value of [Zn] / ([In] + [Zn] + [Mg]) is less than 0.05, the specific resistance of the formed transparent conductive film becomes too large or crystallizes. There is. On the other hand, when the value of [Zn] / ([In] + [Zn] + [Mg]) is more than 0.25, the specific resistance of the formed transparent conductive film may be too large.

Composition of magnesium Further, in the sputtering target of the present invention, [Mg] / ([In] + [Zn] + [Mg]) = 0.01 to 0.20. When the value of [Mg] / ([In] + [Zn] + [Mg]) is less than 0.01, the specific resistance of the formed transparent conductive film becomes too large or crystallizes. In addition, the transmittance of the transparent conductive film may not increase. On the other hand, when the value of [Mg] / ([In] + [Zn] + [Mg]) is more than 0.25, the specific resistance of the formed transparent conductive film may be too large.

  (5) Moreover, this invention is a sputtering target in any one of said (1)-(4) characterized by including a positive tetravalent metal oxide further.

  Positive tetravalent means that the valence of the metal atom in the metal oxide is +4. By including a positive tetravalent metal oxide, the bulk resistance of the sputtering target is lowered, and abnormal discharge can be prevented.

(6) Further, the present invention, the metal oxide of the positive quadrivalent _is a sputtering target according to (5), wherein the SnO _2, ZrO _2, and GeO 2, CeO _2.

Among positive tetravalent metal oxides, SnO ₂ , ZrO ₂ , GeO ₂ , and CeO ₂ can be preferably used.

(7) Further, the present invention _is characterized in that it comprises SnO _2, ZrO _2, GeO 2, CeO _2, and one or more metal oxides selected from the group M consisting of _Ga 2 _{O 3} It is a sputtering target as described in said (6).

  (8) Moreover, this invention WHEREIN: The addition amount of the 1 type (s) or 2 or more types of said metal oxide chosen from the said group M is [M] / [all metals] = 0.0001-0.15. The sputtering target according to (7) above, wherein Here, [M] is a metal in one or more metal oxides selected from the group M per unit volume, that is, any one of Sn, Zr, Ge, Ce, and Ga per unit volume. The number of atoms of one kind or two or more kinds is represented, and [all metals] means all metals per unit volume, that is, one or two kinds selected from the group M and In, Zn, Mg per unit volume. The total number of atoms of the metal in the above metal oxide is represented.

  In the sputtering target, the value of [M] / [all metals] is 0.0001 to 0.15, preferably 0.0003 to 0.12, and more preferably 0.0005 to 0.1. . When the value of [M] / [all metals] is less than 0.0001, the effect of addition may not be obtained, while when the value of [M] / [all metals] exceeds 0.15. May hardly improve the etching property of the formed transparent conductive film.

Invention of Amorphous Transparent Conductive Film (9) Further, the present invention is an amorphous transparent conductive film characterized by containing indium oxide, zinc oxide, and magnesium oxide.

  When the transparent conductive film contains indium oxide, zinc oxide, and magnesium oxide, a completely amorphous transparent conductive film can be obtained. By making the transparent conductive film amorphous in this way, almost no etching residue is generated during etching. Moreover, when a transparent conductive film contains magnesium oxide, the fall of the light transmittance in 400-450 nm range of a transparent conductive film can be prevented effectively.

  (10) In the present invention, [In] / ([In] + [Zn] + [Mg]) = 0.74 to 0.94, and [Zn] / ([In] + [Zn] + [Mg]) = 0.05 to 0.25, and [Mg] / ([In] + [Zn] + [Mg]) = 0.01 to 0.20. ). Here, [In] represents the number of indium atoms per unit volume, [Zn] represents the number of zinc atoms per unit volume, and [Mg] represents the number of magnesium atoms per unit volume. .

Composition of indium In the transparent conductive film of the present invention, the value of [In] / ([In] + [Zn] + [Mg]) is 0.74 to 0.94, preferably 0.7 to 0.92. More preferably, it is 0.75-0.9. When the value of [In] / ([In] + [Zn] + [Mg]) is less than 0.74, the specific resistance of the transparent conductive film may be too high, and [In] / ( When the value of [In] + [Zn] + [Mg]) exceeds 0.94, the transparent conductive film may be easily crystallized or the specific resistance may be increased.

Composition of zinc In the transparent conductive film of the present invention, the value of [Zn] / ([In] + [Zn] + [Mg]) is 0.05 to 0.25, preferably 0.07 to 0.00. 25, more preferably 0.08 to 0.22. When the value of [Zn] / ([In] + [Zn] + [Mg]) is less than 0.05, the transparent conductive film may be easily crystallized or the specific resistance may be increased. On the other hand, when the value of [Zn] / ([In] + [Zn] + [Mg]) is more than 0.25, the specific resistance of the transparent conductive film may be too large.

Composition of magnesium In the transparent conductive film of the present invention, the value of [Mg] / ([In] + [Zn] + [Mg]) is 0.01-0.2, preferably 0.01-0. 15, more preferably 0.02 to 0.1. When the value of [Mg] / ([In] + [Zn] + [Mg]) is less than 0.01, the transmittance of the transparent conductive film does not increase, it becomes easy to crystallize, Resistance may increase. When the value of [Mg] / ([In] + [Zn] + [Mg]) is more than 0.20, the specific resistance of the formed transparent conductive film may be too large.
When the content of In, Zn, and Mg in the transparent conductive film is not within the above range, the transparent conductive film may not obtain preferable transparency, specific resistance, etching properties, and the like.

  (11) Further, the present invention is the amorphous transparent conductive film according to the above (9) or (10), further comprising a positive tetravalent metal oxide.

  By including a positive tetravalent metal oxide in the transparent conductive film, the bulk resistance of the target is reduced, and the transparent conductive film can be formed in a stable discharge state. For this reason, a more stable transparent conductive film is obtained.

(12) Further, in the present invention, the positive tetravalent metal oxide is SnO ₂ , ZrO ₂ , GeO ₂ , or CeO ₂ , wherein the amorphous transparent conductive film according to the above (11) It is.

Among positive tetravalent metal oxides, SnO ₂ , ZrO ₂ , GeO ₂ , and CeO ₂ can be preferably used.

(13) Further, the present _invention provides a comprising a SnO 2, ZrO _2, and _GeO 2, CeO _2, and one or more metal oxides selected from the group M consisting of _Ga 2 _{O 3} The amorphous transparent conductive film according to (9) or (10).

  (14) Further, according to the present invention, the addition amount of the one or more metal oxides selected from the group M is [M] / [all metals] = 0.0001 to 0.15. The amorphous transparent conductive film as described in (13) above. Here, [M] is a metal in one or more metal oxides selected from the group M per unit volume, that is, any one of Sn, Zr, Ge, Ce, and Ga per unit volume. The number of atoms of one kind or two or more kinds is represented, and [all metals] means all metals per unit volume, that is, one or two kinds selected from the group M and In, Zn, Mg per unit volume. The total number of atoms of the metal in the above metal oxide is represented.

  In the transparent conductive film, the value of [M] / [all metals] is [M] / [all metals] = 0.0001 to 0.15, preferably 0.0003 to 0.12, and more preferably. Is 0.0005 to 0.1. When the value of [M] / [All metals] is less than 0.0001, the effect of addition may not be obtained. When the value of [M] / [All metals] exceeds 0.15, The etching property of the transparent conductive film may hardly improve.

As described above, the sputtering target of the present invention hardly generates nodules during sputtering.
In addition, the amorphous transparent conductive film of the present invention is almost free of residues and the like by etching with a weak acid (organic acid or the like), and is excellent in transparency (light transmittance) in the 400 to 450 nm region.

  Hereinafter, preferred embodiments of the present invention will be described.

Target 1
An In ₂ O ₃ powder having an average particle size of 1 μm or less, a ZnO powder having an average particle size of 1 μm or less, and an MgO powder having an average particle size of 1 μm or less are weighed in a predetermined ratio, mixed, and then placed in a resin pot. Further, water was added, and wet ball mill mixing using hard ZrO ₂ balls was performed. At this time, the mixing time was 20 hours. By this mixing, the obtained mixed slurry was taken out, filtered, dried and granulated. The obtained granulated product was put into a mold and molded by applying a pressure of 3 ton / cm ² with a cold isostatic press to obtain a molded product.

Next, the obtained molded body was sintered as follows. First, the compact was placed in a sintering furnace, and oxygen was introduced at a rate of 5 liters / minute per volume of 0.1 m ³ in the sintering furnace. In this atmosphere, the molded body was sintered at 1470 ° C. for 5 hours. At this time, the temperature in the sintering furnace was increased at a rate of 1 ° C./min up to 1000 ° C., and was increased at a rate of 3 ° C./min between 1000 ° C. and 1470 ° C.
Thereafter, the inflow of oxygen was stopped, and the temperature in the sintering furnace was lowered from 1470 ° C. to 1300 ° C. at 10 ° C./min. Then, Ar was introduced at a rate of 10 liters / minute per volume of 0.1 m ³ in the sintering furnace, and in this atmosphere, the molded body was held at 1300 ° C. for 3 hours, and then allowed to cool and fire. A ligature was obtained.

The relative density of the obtained sintered body was determined as follows. First, it was measured by the Archimedes method using water, and the relative density was calculated from the theoretical density. The value was 97%. This relative density is shown in FIG. The theoretical density at this time was calculated from the weight fraction of oxides of In ₂ O ₃ crystal (Bixbite type structure) free from oxygen defects, Zn, and Mg.

  Further, when the Zn and Mg contents in the sintered body are quantitatively analyzed by ICP (Inductively Coupled Plasma) emission analysis, the charged composition when mixing the raw material powder is maintained even in the sintered body. It was confirmed that At this time, the value of [In] / ([In] + [Zn] + [Mg]), which is a specific atomic composition ratio in the confirmed sintered body, and [Zn] / ([In] + [Zn] ] + [Mg]) and [Mg] / ([In] + [Zn] + [Mg]) are shown in FIG.

  In FIG. 1, [In] represents the number of indium atoms per unit volume in the sintered body, [Zn] represents the number of zinc atoms per unit volume in the sintered body, and [Mg ] Represents the number of magnesium atoms per unit volume in the sintered body.

  Next, the sputtering surface of the sintered body was polished with a cup grindstone, processed to a diameter of 100 mm and a thickness of 5 mm, and a backing plate was bonded using an In-based alloy to produce a sputtering target 1. First, the bulk resistance of the sputtering target 1 is measured by measuring the specific resistance of the target 1 by a four-probe method using a Loresta (Mitsubishi Yuka), and based on the measured specific resistance value, Obtained by calculation. The calculated value of the bulk resistance is shown in FIG.

The form in which zinc and magnesium are contained in the target 1 is a composite oxide of indium oxide-zinc oxide (for example, In ₂ Zn ₅ O) rather than being dispersed as zinc oxide (ZnO) or magnesium oxide (MgO). ₈ , In ₂ Zn ₇ O ₁₀ , In ₂ Zn ₃ O ₆ , In ₂ Zn ₄ O ₇ , etc.). FIG. 2 shows a diagram representing an X-ray chart of the target 1. In FIG. 2, the vertical axis represents the intensity of the diffracted X-ray, and the horizontal axis represents the angle of the diffracted X-ray. The hexagonal layered compound composed of indium oxide and zinc oxide has a general formula of In ₂ O ₃ (ZnO) such as In ₂ Zn ₃ O ₆ , In ₂ Zn ₄ O ₇ , and In ₂ Zn ₅ O _8. It is preferably represented by _m (where m is an integer of 3 to 20).

  When zinc atoms and magnesium atoms are substituted and dissolved in the indium sites of indium oxide and dispersed in the indium oxide sintered body at the atomic level, the bulk resistance of the target 1 becomes too large, and during sputtering, Discharge is not stable and may cause abnormal discharge.

Indium oxide, zinc oxide, and magnesium oxide in the target 1 are dispersed, for example, in the form of a hexagonal layered compound composed of indium oxide and zinc oxide and in the form of In ₂ MgO ₄ composed of indium oxide and magnesium oxide. It is preferable. By dispersing in such a form, the bulk resistance of the target 1 does not become too large, and the discharge is stabilized during sputtering.

It was confirmed by X-ray diffraction that indium oxide, zinc oxide, and magnesium oxide in the target 1 of Example 1 were dispersed in the form of the hexagonal layered compound and In ₂ MgO ₄ . In addition, the above forms in which indium oxide, zinc oxide, and magnesium oxide in the sputtering target 1 were dispersed were confirmed based on crystal peaks obtained by X-ray diffraction.

The hexagonal layered compound composed of indium oxide and zinc oxide has a general formula of In ₂ O ₃ (ZnO) such as In ₂ Zn ₃ O ₆ , In ₂ Zn ₄ O ₇ , and In ₂ Zn ₅ O _8. It is preferably represented by _m (where m is an integer of 3 to 20).

  By dispersing in such a form, the bulk resistance of the target 1 becomes less than 10 mΩcm, and stable sputtering becomes possible. Moreover, when this target 1 was used for sputtering, no nodules were generated (FIG. 1).

Transparent conductive film 1a
After mounting the obtained target 1 on a DC sputtering apparatus, a transparent conductive film 1a having a thickness of 130 nm was formed on a slide glass at 200 ° C. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 1a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring X-ray diffraction of the transparent conductive film 1a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 1a was etched using a weak acid, no residue was generated (FIG. 1).

  Thus, in Example 1, the transparent conductive film 1a having an improved light transmittance at 400 to 450 nm while being amorphous was obtained.

Target 2
Except that the mixing ratio of In ₂ O ₃ powder having an average particle size of 1 μm or less, ZnO powder having an average particle size of 1 μm or less, and MgO powder having an average particle size of 1 μm or less are different from those of Example 1 above In the same manner, the above powder was mixed, molded, and sintered to obtain a sintered body. The relative density of the obtained sintered body was determined by the same method as in Example 1. The relative density obtained is shown in FIG.

  In addition, as in Example 1 above, when the contents of Zn and Mg in the obtained sintered body were quantitatively analyzed by ICP emission analysis, the charged composition when mixing the raw material powder was the same even in the sintered body. It was confirmed that it was maintained. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

    Next, in the same manner as in Example 1 above, a backing plate was bonded to the sputtered surface of this sintered body to produce a sputtering target 2. Further, the bulk resistance of the target 2 was determined in the same manner as in Example 1 above. The obtained bulk resistance value is shown in FIG. Moreover, when this target 2 was used for sputtering, no nodules were generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 2 of Example 2 are present in the form of a hexagonal layered compound having the same form as in Example 1 and In ₂ MgO _4. It was confirmed by X-ray diffraction.

Transparent conductive film 2a
After mounting the obtained target 2 on a DC sputtering apparatus, a transparent conductive film 2a having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Example 1. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 2a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring the X-ray diffraction of this transparent conductive film 2a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 2a was etched using weak acid, no residue was generated (FIG. 1).
As described above, also in Example 2, the transparent conductive film 2a having an improved light transmittance at 400 to 450 nm was obtained while being amorphous, as in Example 1.

Target 3
Except that the mixing ratios of In ₂ O ₃ powder having an average particle size of 1 μm or less, ZnO powder having an average particle size of 1 μm or less, and MgO powder having an average particle size of 1 μm or less are different from those of Example 1 and In the same manner as in No. 2, the above powder was mixed, molded, and sintered to obtain a sintered body. The relative density of the obtained sintered body was determined by the same method as in Examples 1 and 2 above. The relative density obtained at this time is shown in FIG.

  In addition, as in Examples 1 and 2 above, when the contents of Zn and Mg in the obtained sintered body were quantitatively analyzed by ICP emission analysis, the charged composition when mixing the raw material powder was sintered. It was confirmed that it was maintained throughout the body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, in the same manner as in Examples 1 and 2, a backing plate was bonded to the sputtering surface of this sintered body to produce a sputtering target 3. Further, the bulk resistance of the target 3 was determined in the same manner as in Examples 1 and 2 above. The obtained bulk resistance value is shown in FIG. Moreover, nodule was not generated when sputtering was performed using this target 3 (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 3 of Example 3 are present in the form of a hexagonal layered compound having the same form as in Examples 1 and 2 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 3a
After mounting the obtained target 3 on a DC sputtering apparatus, a transparent conductive film 3a having a thickness of 130 nm was formed on a slide glass at 200 ° C. as in Examples 1 and 2. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 3a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring the X-ray diffraction of the transparent conductive film 3a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 3a was etched using weak acid, no residue was generated (FIG. 1).
As described above, in Example 3, as in Examples 1 and 2, a transparent conductive film 3a having an improved light transmittance at 400 to 450 nm was obtained while being amorphous.

Target 4
Except that the mixing ratios of In ₂ O ₃ powder with an average particle size of 1 μm or less, ZnO powder with an average particle size of 1 μm or less, and MgO powder with an average particle size of 1 μm or less are different from those in Examples 1 to In the same manner as in No. 3, the above powder was mixed, molded, and sintered to obtain a sintered body. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-3. The relative density obtained is shown in FIG.

  In addition, as in Examples 1 to 3, the content of Zn and Mg in the obtained sintered body was quantitatively analyzed by ICP emission analysis, and the charged composition when mixing the raw material powder was sintered. It was confirmed that it was maintained throughout the body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, in the same manner as in Examples 1 to 3, a backing plate was bonded to the sputtering surface of this sintered body to produce a sputtering target 4. Further, the bulk resistance of the target 4 was determined by the same method as in Examples 1 to 3 above. The obtained bulk resistance value is shown in FIG. Moreover, when this target 4 was used for sputtering, no nodules were generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 4 of Example 4 are present in the form of a hexagonal layered compound having the same form as in Examples 1 to 3 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 4a
After mounting the obtained target 2 on a DC sputtering apparatus, a transparent conductive film 4a having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Example 1. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 4a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring the X-ray diffraction of the transparent conductive film 4a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 4a was etched using a weak acid, no residue was generated (FIG. 1).
Thus, also in this Example 4, the transparent conductive film 4a in which the light transmittance in 400-450 nm was improved was obtained, although it was amorphous like the said Examples 1-3.

Target 5
Further, except for the point that SnO ₂ powder was mixed at a predetermined ratio, the powder was mixed, molded and sintered at the same composition ratio as in Example 1 to obtain a sintered body. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-4. The relative density obtained is shown in FIG.

  Moreover, when the content of Zn, Mg, and Sn in the obtained sintered body was quantitatively analyzed by ICP emission analysis in the same manner as in Examples 1 to 4, preparation for mixing raw material powders It was confirmed that the composition was maintained even in the sintered body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  In this patent, M means a group consisting of Sn, Zr, and Ge. In particular, in FIG. 1, M represents one of Sn, Zr, and Ge. [M] represents the number of Sn, Zr, and Ge atoms per unit volume in the sintered body.

  Next, in the same manner as in Examples 1 to 4, a backing plate was bonded to the sputter surface of the sintered body to produce a sputtering target 5. Further, the bulk resistance of the target 5 was determined by the same method as in Examples 1 to 4 above. The obtained bulk resistance value is shown in FIG. Moreover, when this target 5 was used for sputtering, no nodules were generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 5 of Example 5 are present in the form of a hexagonal layered compound having the same form as in Examples 1 to 4 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 5a
After mounting the obtained target 5 on a DC sputtering apparatus, a transparent conductive film 5a having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Examples 1 to 4. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 5a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring X-ray diffraction of this transparent conductive film 5a, no peak was observed and it was found to be amorphous. Moreover, when this transparent conductive film 5a was etched using a weak acid, no residue was generated (FIG. 1).
Thus, also in this Example 5, the transparent conductive film 5a with which the light transmittance in 400-450 nm was improved was obtained, although it was amorphous like the said Examples 1-4.

Target 6
Except that the mixing ratio of In ₂ O ₃ powder having an average particle size of 1 μm or less, ZnO powder having an average particle size of 1 μm or less, MgO powder having an average particle size of 1 μm or less, and SnO ₂ powder are different, In the same manner as in Example 5, the powder was mixed, molded, and sintered to obtain a sintered body. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-5. The relative density obtained is shown in FIG.

  In addition, as in Example 5 above, the contents of Zn, Mg, and Sn in the obtained sintered body were quantitatively analyzed by ICP emission spectrometry. It was confirmed that it was maintained even during ligation. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, in the same manner as in Examples 1 to 5, a backing plate was bonded to the sputtering surface of the sintered body to produce a sputtering target 6. Furthermore, the bulk resistance of this target 6 was calculated | required by the method similar to the said Examples 1-5. The obtained bulk resistance value is shown in FIG. Moreover, when this target 6 was used for sputtering, no nodules were generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 6 of Example 6 are present in the form of a hexagonal layered compound having the same form as in Examples 1 to 5 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 6a
After mounting the obtained target 6 on a DC sputtering apparatus, a transparent conductive film 6a having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Examples 1 to 5. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 6a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of X-ray diffraction measurement of this transparent conductive film 6a, no peak was observed and it was found to be amorphous. Moreover, when this transparent conductive film 6a was etched using weak acid, no residue was generated (FIG. 1).
Thus, also in the present Example 6, the transparent conductive film 6a with which the light transmittance in 400-450 nm was improved was obtained, although it was amorphous like the said Examples 1-5.

Target 7
Except that the mixing ratio of In ₂ O ₃ powder having an average particle size of 1 μm or less, ZnO powder having an average particle size of 1 μm or less, MgO powder having an average particle size of 1 μm or less, and SnO ₂ powder are different, In the same manner as in Examples 5 and 6, the powder was mixed, molded, and sintered to obtain a sintered body. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-6. The relative density obtained is shown in FIG.

  Similarly to Examples 5 and 6, the contents of Zn, Mg, and Sn in the obtained sintered body were quantitatively analyzed by ICP emission analysis. As a result, the charged composition when mixing the raw material powder was It was confirmed that it was maintained even in the sintered body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, in the same manner as in Examples 1 to 6, a backing plate was bonded to the sputter surface of the sintered body to produce a sputtering target 7. Further, the bulk resistance of the target 7 was obtained by the same method as in Examples 1 to 6. The obtained bulk resistance value is shown in FIG. Further, when sputtering was performed using this target 7, no nodules were generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 7 of Example 7 are present in the form of a hexagonal layered compound having the same form as in Examples 1 to 6 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 7a
After mounting the obtained target 7 on a DC sputtering apparatus, a transparent conductive film 7a having a thickness of 130 nm was formed on a slide glass at 200 ° C. as in Examples 1 to 6. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 7a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring the X-ray diffraction of this transparent conductive film 7a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 7a was etched using weak acid, no residue was generated (FIG. 1).
Thus, also in this Example 7, the transparent conductive film 7a in which the light transmittance in 400-450 nm was improved was obtained, although it was amorphous like the said Examples 1-6.

Target 8
Furthermore, except that a mixture of ZrO ₂ powder in a predetermined ratio, in the same composition ratio as in Example 4, the powder were mixed and molded and sintered to obtain a sintered body. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-7. The relative density obtained is shown in FIG.

  Further, when the contents of Zn, Mg, and Zr in the obtained sintered body were quantitatively analyzed by ICP emission analysis in the same manner as in Examples 1 to 7, preparation for mixing raw material powders was performed. It was confirmed that the composition was maintained even in the sintered body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, a sputtering target 8 was manufactured by attaching a backing plate to the sputter surface of the sintered body in the same manner as in Examples 1 to 7. Further, the bulk resistance of the target 8 was determined by the same method as in Examples 1-7. The obtained bulk resistance value is shown in FIG. Further, when sputtering was performed using this target 8, nodules were not generated (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 8 of Example 8 exist in the form of a hexagonal layered compound having the same form as in Examples 1 to 7 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 8a
After mounting the obtained target 8 on a DC sputtering apparatus, a transparent conductive film 8a having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Examples 1 to 7. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 8a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of X-ray diffraction measurement of this transparent conductive film 8a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 8a was etched using weak acid, no residue was generated (FIG. 1).
As described above, also in Example 8, a transparent conductive film 8a having an improved light transmittance at 400 to 450 nm was obtained while being amorphous, as in Examples 1 to 7.

Target 9
A sintered body was obtained by mixing, molding, and sintering the powder in the same composition ratio as in Example 8 except that GeO ₂ powder was mixed instead of ZrO ₂ powder. The relative density of the obtained sintered compact was calculated | required by the method similar to the said Examples 1-8. The relative density obtained is shown in FIG.

  Further, when the contents of Zn, Mg, and Ge in the obtained sintered body were quantitatively analyzed by ICP emission analysis in the same manner as in Examples 1 to 8, preparation for mixing raw material powders was performed. It was confirmed that the composition was maintained even in the sintered body. The specific composition ratio values in the sintered body confirmed at this time are shown in FIG.

  Next, a sputtering target 9 was manufactured by attaching a backing plate to the sputter surface of the sintered body in the same manner as in Examples 1 to 8 above. Further, the bulk resistance of the target 9 was determined by the same method as in Examples 1 to 8. The obtained bulk resistance value is shown in FIG. Moreover, nodule was not generated when sputtering was performed using this target 9 (FIG. 1).

Further, indium oxide, zinc oxide, and magnesium oxide in the sputtering target 9 of Example 9 exist in the form of a hexagonal layered compound having the same form as in Examples 1 to 8 and In ₂ MgO _4. This was confirmed by X-ray diffraction.

Transparent conductive film 9a
After mounting the obtained target 9 on a DC sputtering apparatus, a transparent conductive film 9a having a thickness of 130 nm was formed on a slide glass at 200 ° C. as in Examples 1 to 8. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film 9a were measured. The measured specific resistance and light transmittance values are shown in FIG. Further, as a result of measuring the X-ray diffraction of the transparent conductive film 9a, it was found that no peak was observed and the film was amorphous. Moreover, when this transparent conductive film 9a was etched using a weak acid, no residue was generated (FIG. 1).
As described above, in Example 9, similarly to Examples 1 to 8, a transparent conductive film 9a having an improved light transmittance at 400 to 450 nm was obtained while being amorphous.

  The sputtering target of the present invention is not particularly limited except that it contains three components of indium oxide, zinc oxide, and magnesium oxide at a predetermined ratio. Therefore, for example, it can be manufactured by mixing, molding and sintering the powder composed of the above three components using a known method.

In addition, if it is in the range which does not impair the effect of this invention, it is also preferable to contain components other than the said 3 component. For example, in Examples 5 to 9, the sputtering target contains SnO ₂ , ZrO ₂ , or GeO _{2 in} a predetermined ratio in addition to the above three components. It is also preferable to contain Ga ₂ O ₃ , CeO ₂ or the like. In addition to the above three components, it is also preferable to simultaneously contain two or more components selected from SnO ₂ , ZrO ₂ , GeO ₂ , Ga ₂ O ₃ , CeO _{2 and the} like.

When Ga ₂ O ₃ is added to the target, InGaMgO ₄ , InGaMg ₂ O ₅ , InGaMgZnO ₅ , InGaMgZn ₂ O ₆ , In ₂ Ga ₂ ZnO ₇ , InGaZnO ₄ , InGaZn ₂ O ₅ , InGaZn ₃ O ₆ , InGaZn ₄ O ₇ , InGaZn ₅ O ₈ , InGaZn ₆ O ₉ , InGaZn ₇ O ₁₀ , and the like are preferably dispersed in the form of a composite oxide.

The sputtering target of Example 10 contains components such as SnO ₂ , ZrO ₂ , GeO ₂ , Ga ₂ O ₃ , and CeO ₂ in addition to the three components of indium oxide, zinc oxide, and magnesium oxide. Even in this case, the sputtering target of Example 10 has the same effects as the sputtering targets of Examples 1 to 9. Moreover, the transparent conductive film formed using such a sputtering target also has the same effects as the transparent conductive films of Examples 1 to 9.

Comparative Example 1
ITO target The same treatment and operation as in Examples 1 to 9 were performed using a commercially available ITO target, that is, a sputtering target composed of indium oxide and tin oxide.
The relative density, composition ratio, and bulk resistance of the ITO target were determined in the same manner as in Examples 1-9. The obtained relative density, composition ratio, and bulk resistance are shown in FIG. In addition, [X] in FIG. 1 represents the number of Sn or Zn atoms per unit volume in the target. Further, when sputtering was performed using this ITO target, nodules were generated (FIG. 1).

Transparent conductive film After mounting this ITO target on a DC sputtering apparatus, a transparent conductive film having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Examples 1 to 9. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film were measured. The measured specific resistance and light transmittance values are shown in FIG. Moreover, when this transparent conductive film was etched using a weak acid, a residue was generated (FIG. 1).

  Thus, when the transparent conductive film of Comparative Example 1 was etched using a weak acid, an etching residue was generated.

"Comparative Example 2"
IZO target A commercially available IZO (indium-zinc oxide: “IZO” is a registered trademark) target, that is, a sputtering target composed of indium oxide and zinc oxide, was used for the same treatment and operation as in Examples 1 to 9 above. went.
The relative density, composition ratio, and bulk resistance of the IZO target were determined by the same method as in Examples 1-9. The obtained relative density, composition ratio, and bulk resistance are shown in FIG. Further, when sputtering was performed using this IZO target, nodules were generated (FIG. 1).

Transparent conductive film After mounting this IZO target on a DC sputtering apparatus, a transparent conductive film having a thickness of 130 nm was formed on a slide glass at 200 ° C. in the same manner as in Examples 1 to 9. The specific resistance and light transmittance (400 nm, 450 nm) of the formed transparent conductive film were measured. The measured specific resistance and light transmittance values are shown in FIG. Moreover, when this transparent conductive film was etched using a weak acid, no residue was generated (FIG. 1).
Thus, in the transparent conductive film of Comparative Example 2, the light transmittance at 400 nm to 450 nm was not so high.

It is a figure showing the physical property parameter of the target for sputtering in this Examples 1-9 and comparative examples 1 and 2 and a transparent conductive film. It is a figure showing the X-ray chart of the target 1 in the present Example 1. FIG.

Claims (5)

Indium oxide;
Zinc oxide,
Magnesium oxide,
Comprises, [In] / ([In ] + [Zn] + [Mg]) = a 0.74~0.94, [Zn] / ([ In] + [Zn] + [Mg]) = 0 0.05 to 0.25, and [Mg] / ([In] + [Zn] + [Mg]) = 0.01 to 0.20. Here, [In] represents the number of indium atoms per unit volume, [Zn] represents the number of zinc atoms per unit volume, and [Mg] represents the number of magnesium atoms per unit volume. . The amorphous transparent conductive film according to claim 1 , further comprising a positive tetravalent metal oxide. 3. The amorphous transparent conductive film according to claim ₂ , wherein the positive tetravalent metal oxide is SnO ₂ , ZrO ₂ , GeO ₂ , or CeO ₂ . _{2. The} amorphous material according to claim 1 , comprising one or more metal oxides selected from the group M consisting of SnO ₂ , ZrO ₂ , GeO ₂ , CeO ₂ , and Ga ₂ O _3. Transparent conductive film. The amount of the group one selected from M or two or more of metal oxides according to claim 4, characterized in that the [M] / [total metal] = 0.0001 to 0.15 Amorphous transparent conductive film. Here, [M] is a metal in one or more metal oxides selected from the group M per unit volume, that is, any one of Sn, Zr, Ge, Ce, and Ga per unit volume. The number of atoms of one kind or two or more kinds is represented, and [all metals] means all metals per unit volume, that is, one or two kinds selected from the group M and In, Zn, Mg per unit volume. The total number of atoms of the metal in the above metal oxide is represented.

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