JP6036367B2 - Conductive oxide and semiconductor oxide film - Google Patents

Description

  The present invention relates to a conductive oxide and a semiconductor oxide film. More specifically, the present invention relates to a conductive oxide having a lower rare metal content and capable of suppressing a decrease in the formation rate of a semiconductor oxide film. The present invention relates to a conductive oxide and a semiconductor oxide film formed using the conductive oxide.

  Conventionally, an amorphous silicon film has been used for a channel layer of a thin film transistor (TFT) in a liquid crystal display device, a thin film EL (Electro Luminescence) display device, an organic EL display device, or the like. However, in recent years, a semiconductor oxide film containing a conductive oxide such as indium (In) -gallium (Ga) -zinc (Zn) -based composite oxide (IGZO) as a main component has been replaced with an amorphous silicon film. It attracts attention as a channel layer of TFT. IGZO has the advantage of higher carrier mobility than amorphous silicon.

  For example, in Japanese Patent Application Laid-Open No. 2008-199005 (hereinafter referred to as Patent Document 1), a technique for forming a semiconductor oxide film containing IGZO as a main component by sputtering using a sintered body of conductive oxide powder as a target. Is disclosed. Hereinafter, formation of the semiconductor oxide disclosed in Patent Document 1 will be described. First, the target and the substrate are arranged to face each other in the sputtering apparatus. Then, a voltage is applied to the target, and the target surface is sputtered with rare gas ions. Thereby, constituent atoms jump out from the target surface and are deposited on the substrate. In this manner, a semiconductor oxide film containing IGZO as a main component is formed on the substrate.

JP 2008-199005 A

  The conductive oxide made of IGZO disclosed in Patent Document 1 contains a rare metal such as indium, gallium, or zinc. Since the supply amount of such a rare metal is unstable, it is necessary to further reduce the content of the rare metal in order to obtain a conductive oxide stably. On the other hand, a conductive oxide containing aluminum instead of gallium has also been proposed. However, this conductive oxide has a problem that the rate of forming a semiconductor oxide film by sputtering or the like is lower than that of a conductive oxide made of IGZO. Therefore, from the viewpoint of stable supply of conductive oxides and improvement of productivity of liquid crystal display devices, the conductive oxide has a lower rare metal content and can suppress a decrease in the formation rate of the semiconductor oxide film. Things are needed.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a conductive oxide that has a lower rare metal content and can suppress a decrease in the formation rate of a semiconductor oxide film, and It is to provide a semiconductor oxide film formed using a conductive oxide.

The conductive oxide according to one aspect of the present invention is a conductive oxide having a crystal phase having a basic structure which is the same crystal structure as InAlZnO ₄ . The conductive oxide is composed of a composite oxide of indium, aluminum, and a divalent metal. The atomic concentration ratio of aluminum to indium in the crystal phase is greater than 1 and 1.2 or less. The atomic concentration ratio of the divalent metal to indium in the crystal phase is greater than 1 and 1.2 or less.

  The present inventor has conducted detailed studies on measures for reducing the amount of rare metal contained in a conductive oxide and suppressing a decrease in speed when a semiconductor oxide film is formed using the conductive oxide. went. As a result, even when aluminum is included instead of gallium in a conventional conductive oxide made of a composite oxide of indium, gallium, and zinc, the concentration of metal atoms in the crystal phase is set within a specific range. The present inventors have found that it is possible to suppress a decrease in the formation rate of a semiconductor oxide film and have arrived at the present invention.

Since the conductive oxide according to one aspect of the present invention is composed of a complex oxide of indium, aluminum, and a divalent metal, the conventional conductivity composed of a complex oxide of indium, gallium, and zinc. The rare metal content is lower than that of oxide. The conductive oxide has a crystal phase having a basic structure that is the same crystal structure as InAlZnO ₄ , and an atomic concentration ratio of aluminum and the divalent metal to indium in the crystal phase is greater than 1. It is 1.2 or less. Therefore, compared with the conventional conductive oxide which has a crystal phase in which indium, aluminum, and zinc exist in the same ratio, the formation rate of a semiconductor oxide film can be improved more.

  This will be explained in more detail. First, since each of the atomic concentration ratios is larger than 1, indium is insufficient with respect to aluminum and the divalent metal, or aluminum and the divalent metal. Is present in excess relative to indium. As described above, when the indium content is relatively small with respect to aluminum and the divalent metal, a decrease in speed when forming the semiconductor oxide film is suppressed. On the other hand, since each of the atomic concentration ratios is 1.2 or less, the proportion of the crystalline phase in the conductive oxide is suppressed from decreasing. The crystal phase has a structure in which indium, aluminum, and the divalent metal are arranged in layers, and has a crystal structure that can further improve the formation rate of the semiconductor oxide film. Therefore, a reduction in the formation rate of the semiconductor oxide film can be suppressed by suppressing a reduction in the proportion of the crystal phase. For these reasons, in the conductive oxide, the formation rate of the semiconductor oxide film is higher than that of the conventional conductive oxide having a crystal phase in which indium, aluminum, and the divalent metal exist in the same ratio. Can be further improved. Therefore, according to the conductive oxide according to one aspect of the present invention, there is provided a conductive oxide that has less rare metal content and can suppress a decrease in the formation rate of the semiconductor oxide film. can do. In the conductive oxide, each of the atomic concentration ratios is more preferably 1.1 or more and 1.2 or less.

  In the conductive oxide, the divalent metal may be zinc. The divalent metal may be magnesium. Thus, in the conductive oxide, various metals can be employed as the divalent metal.

The conductive oxide according to another aspect of the present invention is a conductive oxide having a crystal phase having a basic structure which is the same crystal structure as InAlZnO ₄ . The conductive oxide is composed of a composite oxide of indium, aluminum, a trivalent metal, and one or more divalent metals. The total atomic concentration ratio of aluminum and trivalent metal to indium in the crystal phase is greater than 1 and 1.2 or less. The total atomic concentration ratio of the divalent metal to indium in the crystal phase is greater than 1 and 1.2 or less.

The conductive oxide according to another aspect of the present invention is composed of a composite oxide of indium, aluminum and a trivalent metal, and one or more kinds of divalent metals. Compared to conventional conductive oxides composed of complex oxides with zinc, the rare metal content is lower. The conductive oxide has a crystal phase having a basic structure that is the same crystal structure as InAlZnO ₄ , and the total atomic concentration of aluminum and the trivalent metal with respect to indium in the crystal phase, and the above 2 The total atomic concentration of the valent metals is greater than 1 and 1.2 or less. Therefore, the conductive oxide has a conventional crystal phase in which indium, aluminum, and a divalent metal exist in the same ratio for the same reason as the conductive oxide according to one aspect of the present invention. Compared to the conductive oxide, the formation rate of the semiconductor oxide film can be further improved. Therefore, according to the conductive oxide according to another aspect of the present invention, there is provided a conductive oxide that has a lower rare metal content and can suppress a decrease in the formation rate of the semiconductor oxide film. can do.

  In the conductive oxide, the trivalent metal may be gallium, and the divalent metal may be zinc and magnesium. Thus, in the conductive oxide, various metals can be used as the trivalent metal and the divalent metal.

In the conductive oxide, the area ratio of the crystal phase may be 95% or more and 100% or less. Thereby, the formation rate of the semiconductor oxide can be further improved. Here, the ratio of the area of the crystal phase means the ratio of the area occupied by the crystal phase in the cut surface when the conductive oxide is cut in an arbitrary plane. Semiconductor oxide according to the present invention The film is formed using the conductive oxide according to the present invention, which can suppress a decrease in the formation rate of the semiconductor oxide film. Therefore, according to the semiconductor oxide film according to the present invention, it is possible to provide a semiconductor oxide film in which a decrease in formation rate is suppressed.

  As is apparent from the above description, according to the conductive oxide according to the present invention, the conductive oxide has a lower rare metal content and can suppress a decrease in the formation rate of the semiconductor oxide film. Things can be provided. Moreover, according to the semiconductor oxide film according to the present invention, it is possible to provide a semiconductor oxide film in which a decrease in the formation rate is suppressed.

It is a flowchart which shows the manufacturing method of an electroconductive oxide roughly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
First, a conductive oxide and a semiconductor oxide film according to Embodiment 1 which is one embodiment of the present invention will be described. The conductive oxide according to this embodiment has a crystal phase having a basic structure which is the same crystal structure as that of crystalline InAlZnO ₄ . The conductive oxide is composed of a composite oxide (InAlZnO ₄ ) of indium (In), aluminum (Al), and zinc (Zn) which is a divalent metal. Thus, the conductive oxide contains Al instead of Ga, which is a conventional conductive oxide made of In, gallium (Ga), and Zn composite oxide (IGZO). Therefore, in the conductive oxide, the total concentration of rare metals In, Ga and Zn is smaller than that of the conventional conductive oxide.

  The basic structure is a rhombohedral structure, which is an In site that should be occupied by In atoms, an Al site that should be occupied by trivalent metals such as Al atoms, and a Zn that should be occupied by divalent metals such as Zn atoms. And an O site to be occupied by oxygen (O) atoms. In the conductive oxide, In sites, Al sites, Zn sites, and O sites are occupied by In atoms, Al atoms, Zn atoms, and O atoms, respectively. The basic structure is the PDF (Powder Diffraction File) No. It is the structure clarified by 40-0258.

  In the crystal phase, the atomic concentration ratio of Al to In is greater than 1 and 1.2 or less, and the atomic concentration ratio of Zn to In is greater than 1 and 1.2 or less. That is, in the crystal phase, In is insufficient with respect to Al and Zn, or Al and Zn are excessive with respect to In. When In is insufficient with respect to Al and Zn, In atoms are lost at the In site of the basic structure. On the other hand, in the state where Al and Zn exist excessively with respect to In, atoms other than Al atoms and Zn atoms that occupy Al sites and Zn sites enter between crystal lattices, or In atoms that occupy In sites. It has been replaced.

  The concentration (unit: atom%) of metal atoms such as In, Al, and Zn in the conductive oxide can be quantified by ICP (Inductively Coupled Plasma) emission analysis. The atomic concentration ratios of Al and Zn to In can be calculated by normalizing the quantified atomic concentrations of Al and Zn with the atomic concentration of In. The concentration of metal atoms is quantified by, for example, three significant digits, and the atomic concentration ratio is evaluated by two significant digits by rounding off the third digit.

  The conductive oxide can be preferably used for a sputtering target, for example. Here, the target is a general term for a material obtained by processing a film by sputtering into a plate shape, or a material obtained by processing the plate shape on a backing plate (back plate for attaching the target). . The backing plate can be produced using a material such as oxygen-free copper, steel, stainless steel, aluminum, aluminum alloy, molybdenum or titanium. The shape of the target is not particularly limited, and may be, for example, a disk shape (flat plate shape) having a diameter of 1 cm, or a diameter exceeding 2 m as in a sputtering target for a large liquid crystal display device. It may be a rectangular shape (flat plate) or a cylindrical shape having a length of 30 cm and a diameter of 8 cm. The semiconductor oxide film according to this embodiment is formed by sputtering using the conductive oxide as a target.

Next, a method for producing a conductive oxide according to this embodiment will be described. In the method for producing a conductive oxide according to the present embodiment, the conductive oxide according to the present embodiment is produced as described below. Referring to FIG. 1, first, a raw material powder preparation step is performed as a step (S10). In this step (S10), for example, a predetermined amount of In ₂ O ₃ powder, Al ₂ O ₃ powder and ZnO powder is prepared as the raw material powder. _{Then, In 2 O 3 -Al 2 O} 3 -ZnO mixture is obtained by mixing a raw material powder was prepared. At this time, the atomic concentration ratio of Al to In in the In ₂ O ₃ —Al ₂ O ₃ —ZnO mixture is greater than 1 and 1.2 or less, and the atomic concentration ratio of Zn to In is greater than 1 and 1.2 or less. Each raw material powder is prepared and mixed so that it becomes.

  Next, a molding process is performed as a process (S20). In this step (S20), a molding process such as press molding is performed on the mixture obtained in the above step (S10). Thereby, the molded object by which the said mixture was shape | molded by the desired shape is obtained.

  Next, a sintering step is performed as a step (S30). In this step (S30), the molded body obtained in the above step (S20) is heated at a predetermined temperature in the air atmosphere. Thereby, the conductive oxide which is the sintered compact of the said raw material powder is formed. By performing steps (S10) to (S30) as described above, the conductive oxide according to the present embodiment is manufactured, and the method for manufacturing the conductive oxide according to the present embodiment is completed. .

As described above, since the conductive oxide according to this embodiment is composed of a composite oxide of In, Al, and Zn (InAlO ₄ ), a composite oxide of In, Ga, and Zn (IGZO). Compared with the conventional conductive oxide consisting of, the content of rare metals is lower. The conductive oxide has a crystal phase having a basic structure that is the same crystal structure as InAlZnO ₄ , and an atomic concentration ratio of Al and Zn to In in the crystal phase is greater than 1 and less than or equal to 1.2 It has become. Therefore, compared with a conventional conductive oxide having a crystal phase in which In, Al, and Zn are present in the same ratio, when used as a sputtering target, the formation rate of the semiconductor oxide film by the sputtering is further improved. be able to.

This will be explained in more detail. First, since each of the atomic concentration ratios is larger than 1, In is insufficient with respect to Al and Zn, or Al and Zn are present excessively with respect to In. It has become a state. In this manner, by making the In content relatively small with respect to Al and Zn, it is possible to suppress a decrease in the formation rate of the semiconductor oxide film due to sputtering. On the other hand, since each of the atomic concentration ratios is 1.2 or less, the proportion of the crystalline phase in the conductive oxide is suppressed from decreasing. Since the crystal phase has a structure in which In, Al, and Zn are arranged in layers, a crystal phase composed of an oxide of In, Al, Zn, or a composite oxide thereof (for example, In ₂ O ₃ , Compared to Al ₂ O ₃ , ZnAl ₂ O _4, etc., the crystal structure has a higher sputtering rate due to rare gas ions (that is, easier to be sputtered). Therefore, a decrease in the sputtering rate can be suppressed by suppressing a decrease in the proportion of the crystal phase. For these reasons, the conductive oxide has a higher rate of formation of a semiconductor oxide film by sputtering compared to a conventional conductive oxide having a crystal phase in which In, Al, and Zn are present in the same ratio. Can be improved. Therefore, according to the conductive oxide according to the present embodiment, it is possible to reduce the rare metal content and suppress the decrease in the formation rate of the semiconductor oxide film when used as a sputtering target. Further, the semiconductor oxide film according to this embodiment is formed by sputtering using the conductive oxide according to this embodiment as a target. Therefore, the semiconductor oxide film according to this embodiment is a semiconductor oxide film in which a decrease in formation rate due to sputtering is suppressed.

The conductive oxide is not limited to a composite oxide of In, Al, and Zn (InAlZnO ₄ ). For example, a composite of In, Al, and Mg that is a divalent metal. It may be made of an oxide (InAlMgO ₄ ). In this case, the Zn site of the basic structure is occupied by Mg atoms, and the atomic concentration ratio of Mg to In in the crystal phase is greater than 1 and less than or equal to 1.2, similar to Zn.

(Embodiment 2)
Next, a conductive oxide and a semiconductor oxide film according to Embodiment 2, which is another embodiment of the present invention, will be described. The conductive oxide according to the present embodiment has a crystal phase having a basic structure which is the same crystal structure as that of crystalline InAlZnO ₄ as in the first embodiment. The conductive oxide according to this embodiment includes a composite oxidation of In, Al and trivalent metal gallium (Ga), and plural kinds of divalent metals Zn and magnesium (Mg). It consists of things.

  The basic structure has an In site, an Al site, a Zn site, and an O site as in the first embodiment. In the present embodiment, the Al site is occupied by Al and Ga that are trivalent metals, and the Zn site is occupied by Zn and Mg that are divalent metals. As the trivalent metal occupying the Al site, for example, thallium (Tl) can be adopted in addition to Ga. In addition to Zn and Mg, for example, calcium (Ca), strontium (Sr), barium (Ba), cadmium (Cd), or mercury (Hg) is adopted as the divalent metal occupying the Zn site. Can do. Moreover, although the divalent metal which comprises the said electroconductive oxide may be multiple types, 1 type may be sufficient as it.

  In the crystal phase, the total atomic concentration ratio of Al and Ga to In is greater than 1 and 1.2 or less, and the total atomic concentration ratio of Zn and Mg to In is greater than 1 and 1.2 or less. Yes. That is, in the crystal phase, as in the first embodiment, the In is insufficient with respect to the trivalent metal (Al, Ga) and the divalent metal (Zn, Mg), or the trivalent metal. In this state, (Al, Ga) and divalent metal (Zn, Mg) exist excessively with respect to In. Further, the conductive oxide can be preferably used for a sputtering target as in the first embodiment. The semiconductor oxide film according to this embodiment is formed by sputtering using the conductive oxide as a target.

As described above, since the conductive oxide according to this embodiment is composed of a composite oxide of In, Al, Ga, Zn, and Mg, the composite oxide of In, Ga, and Zn is used. Compared to the conventional conductive oxide, the rare metal content is lower. Further, the conductive oxide has a crystal phase having a basic structure that is the same crystal structure as InAlZnO ₄ , and the total atomic concentration of Al and Ga with respect to In and the total of Zn and Mg in the crystal phase. The atomic concentration is greater than 1 and 1.2 or less. Therefore, for the same reason as in the case of the first embodiment, the conductive oxide has a semiconductor oxidation compared to a conventional conductive oxide having a crystal phase in which In, Al, and Zn exist in the same ratio. The formation rate of the material film can be further improved. Therefore, according to the conductive oxide according to the present embodiment, as in the case of the first embodiment, the content of the rare metal is reduced and the semiconductor oxide film is used when used as a sputtering target. A decrease in the formation rate can be suppressed.

  In the conductive oxides according to Embodiments 1 and 2, the ratio of the crystal phase is preferably 90% or more and 100% or less. Thereby, the formation rate at the time of forming a semiconductor oxide film using the said conductive oxide can be improved more. Further, the ratio of the crystal phase is more preferably 95% or more and 100% or less. In general, conductive oxides that are sintered bodies inevitably have different crystal phases and amorphous phases at grain boundaries. Therefore, when the semiconductor oxide film is formed, there is a problem in that the composition of the semiconductor oxide film changes due to the presence of different crystal phases in the conductive oxide. On the other hand, in the conductive oxide, change in the composition of the semiconductor oxide film can be suppressed by increasing the ratio of the crystalline phase to 95% to 100%.

The ratio of the crystalline phase in the conductive oxide is measured using, for example, a transmission electron microscope (TEM) and an energy dispersive X-ray spectroscopy (EDX) attached thereto. can do. Specifically, first, it has a composition (In ₂ O ₃ , Al ₂ O ₃ , ZnO, etc.) different from the main component (InAlZnO ₄ ) of the conductive oxide based on a transmission image by TEM and an element distribution image by EDX. Extract the particles. Next, transmission electron diffraction is performed on the particles having different compositions, and the crystal structure is identified. If the identified crystal structure is different from the basic structure, which is the main component crystal structure of the conductive oxide, particles having different compositions are extracted and the ratio is calculated. A ratio obtained by subtracting the ratio of the particles having the different composition from the whole conductive oxide is defined as the ratio of the crystal phase. In addition, since these ratios are calculated from a TEM image, they mean ratios based on occupied areas.

Thus, when the conductive oxide includes a crystal phase having a different composition other than the crystal phase consisting of the main component (InAlZnO ₄ ), the total atomic concentration ratio of Al and Ga to In, and Zn A method for confirming the total atomic concentration ratio of Mg and Mg will be described.

  First, as described above, the ratio of the crystal phase composed of the main component and the crystal phase composed of a composition different from the main component is calculated using TEM and EDX attached thereto. Next, in order to be able to accurately quantify In, Al, and Zn using EDX, the ratio of the crystal phase is corrected using a quantitative value obtained by ICP emission analysis. Next, In, Al, and Zn in the crystal phase composed of the main components are quantified by SEM (Scanning Electron Microscope) -EDX or TEM-EDX. Then, by normalizing the quantified atomic concentration of Al and Zn by the atomic concentration of In, the atomic concentration ratio of Al and Zn to In can be calculated. The concentration of each metal atom is quantified with, for example, three significant digits, and the atomic concentration ratio is evaluated with two significant digits by rounding off the third digit. Thus, by calculating the atomic concentration ratio, it can be confirmed that these values are greater than 1 and 1.2 or less.

(Examples 1-4)
First, In ₂ O ₃ powder (purity: 99.99%, average particle size: 1 μm), Al ₂ O ₃ powder (purity: 99.99%, average particle size: 1 μm), and ZnO powder (purity: 99) .99%, average particle size: 1 μm). Then, the prepared powder was put into a ball mill apparatus, and pulverized and mixed for 6 hours using water as a dispersion solvent. Then, to obtain a _{In 2 O 3 -Al 2 O 3} -ZnO mixture by evaporating the water using a spray dryer. At this time, the atomic concentration ratio of Al to In in the In ₂ O ₃ —Al ₂ O ₃ —ZnO mixture is greater than 1 and 1.2 or less, and the atomic concentration ratio of Zn to In is greater than 1 and 1.2 or less. Raw material powders were prepared so as to be mixed.

Next, the above mixture was pressed and molded, and then further pressure-molded by a cold isostatic press (CIP: Cold Isostatic Press). Thereby, a disk-shaped molded body having a diameter of 100 mm and a thickness of about 9 mm was produced. Next, the produced compact was sintered at a temperature of 1500 ° C. or higher and 1600 ° C. or lower in an air atmosphere to produce a conductive oxide.
(Examples 5 to 8)
An In ₂ O ₃ —Al ₂ O ₃ —MgO mixture was obtained by preparing MgO powder instead of the ZnO powders of Examples 1 to 4 and mixing the raw material powder. Other conditions were the same as in Examples 1 to 4 above.
Example 9
In Examples 1-4, in addition to In ₂ O ₃ powder, Al ₂ O ₃ powder and ZnO powder, Ga ₂ O ₃ powder and MgO powder were further prepared. And the prepared powder was mixed similarly to the said Examples 1-4. At this time, in the mixture, the total atomic concentration ratio of Al and Ga to In is greater than 1 and 1.2 or less, and the total atomic concentration ratio of Zn and Mg to In is greater than 1 and 1.2 or less. Raw material powders were prepared and mixed.
(Comparative Example 1)
Raw material powders were prepared so that the atomic concentration ratio of Al and Zn to In in the In ₂ O ₃ —Al ₂ O ₃ —ZnO mixture of Examples 1 to 4 was 1, and these were mixed. Other conditions were the same as in Examples 1 to 4 above.
(Comparative Example 2)
Raw material powders were prepared so that the atomic concentration ratio of Al and Mg to In in the In ₂ O ₃ —Al ₂ O ₃ —MgO mixture of Examples 5 to 8 was 1, and these were mixed. Other conditions were the same as those in Examples 5-8.
<ICP emission analysis>
The atomic concentrations (atoms%) of In, Al, Ga, Zn and Mg in the conductive oxides of the examples and comparative examples were measured by ICP emission analysis. Then, the atomic concentration ratios of Al, Ga, Zn, and Mg to In were calculated based on the measured atomic concentrations.
<Energy dispersive X-ray analysis>
The conductive oxide of each Example and Comparative Example was cut at an arbitrary surface, and the cut surface was subjected to energy dispersive X-ray analysis using an analytical scanning electron microscope. Thereby, in the cross section of the conductive oxide, the ratio of the area occupied by the crystal phase composed of the basic structure having the same crystal structure as that of the crystalline InAlZnO ₄ was calculated.
<Evaluation of formation rate of semiconductor oxide film>
Using the conductive oxides of the examples and comparative examples as targets, a semiconductor oxide film was formed by direct current (DC) magnetron sputtering as described below. And the speed at the time of forming a semiconductor oxide film was evaluated.

First, the conductive oxides of the examples and comparative examples were processed into a target having a diameter of 3 inches (76.2 mm) and a thickness of 5 mm. Next, the target was placed in the sputtering apparatus so that the surface having a diameter of 3 inches was a sputtering surface. Next, a resin was bonded to the center of a quartz glass substrate (50 mm × 50 mm × 0.5 mm) which is a film formation substrate, and the film formation substrate was placed on a water-cooled substrate holder in a sputtering apparatus. At this time, the distance between the target and the film formation substrate was 40 mm. Next, the inside of the sputtering apparatus was evacuated to about 1 × 10 ⁻⁴ Pa. Next, argon gas was introduced into the deposition chamber with the shutter placed between the deposition substrate and the target, and the pressure in the deposition chamber was set to 0.5 Pa. Next, the surface of the target was cleaned for 10 minutes by applying 120 W DC power to the target and performing sputtering discharge. Next, argon gas was introduced into the deposition chamber, and the pressure in the deposition chamber was set to 0.1 Pa. Next, direct current power of 120 W was applied to the target, the shutter between the film formation substrate and the target was removed, and film formation was performed for 30 minutes. The substrate holder was only cooled with water, no voltage was applied, and the substrate holder was not rotated. Next, the film formation substrate was taken out of the film formation chamber, and the resin adhered to the center portion was peeled off. As a result, the region where the semiconductor oxide film is not formed is exposed, and a step (the thickness of the semiconductor oxide film) between the region where the semiconductor oxide film is formed and the region where the semiconductor oxide film is not formed is exposed. It was measured with a palpation type surface roughness meter. Then, the formation rate of the semiconductor oxide film was calculated by dividing the value (nm) of the film thickness of the semiconductor oxide film by the film formation time (s). Table 1 shows the composition of the conductive oxide, the type of crystal phase and the ratio of the crystal phase, and the formation rate of the semiconductor oxide film in each Example and Comparative Example.

  As is clear from Table 1, in the conductive oxides of Examples 1 to 9, the formation rate of the semiconductor oxide film was higher than those of Comparative Examples 1 and 2. Thereby, the total atomic concentration ratio of trivalent metals (Al, Ga) to In in the crystal phase is set to be larger than 1 and 1.2 or less, and the total atoms of divalent metals (Zn, Mg) with respect to In It was revealed that the formation rate of the semiconductor oxide film is improved by setting the concentration ratio to be greater than 1 and 1.2 or less. Further, as in Examples 1 to 4 and Examples 5 to 8, it became clear that the rate of formation of the semiconductor oxide film increases as the proportion of the crystal phase increases.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The conductive oxide and the semiconductor oxide film of the present invention are required to further reduce the content of rare metal and suppress the decrease in the formation rate of the semiconductor oxide film, The present invention can be particularly advantageously applied to a semiconductor oxide film that is required to suppress the decrease.

Claims (7)

A conductive oxide having a crystal phase having a basic structure which is the same crystal structure as InAlZnO ₄ ,
It consists of a complex oxide of indium, aluminum, and a divalent metal,
The atomic concentration ratio of the aluminum to the indium in the crystalline phase is greater than 1 and less than or equal to 1.2;
The conductive oxide, wherein an atomic concentration ratio of the divalent metal to the indium in the crystal phase is greater than 1 and 1.2 or less.   The conductive oxide according to claim 1, wherein the divalent metal is zinc.   The conductive oxide according to claim 1, wherein the divalent metal is magnesium. A conductive oxide having a crystal phase having a basic structure which is the same crystal structure as InAlZnO ₄ ,
A composite oxide of indium, aluminum and a trivalent metal, and one or more divalent metals,
The total atomic concentration ratio of the aluminum and the trivalent metal to the indium in the crystalline phase is greater than 1 and less than or equal to 1.2;
The conductive oxide, wherein a total atomic concentration ratio of the divalent metal to the indium in the crystal phase is greater than 1 and 1.2 or less. The trivalent metal is gallium,
The conductive oxide according to claim 4, wherein the divalent metal is zinc and magnesium.   The conductive oxide according to any one of claims 1 to 5, wherein a ratio of an area of the crystal phase is 95% or more and 100% or less.   The semiconductor oxide film formed using the conductive oxide of any one of Claims 1-6.

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