KR20130046449A - Sintered oxide and oxide semiconductor thin film - Google Patents

Abstract

An object of the present invention is to provide an oxide sintered body for producing an oxide semiconductor film containing no expensive gallium (Ga). Another object is to provide an oxide semiconductor thin film having the same composition as the oxide sintered body.
Trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), divalent X ions (X ²⁺ ) (where X represents at least one element selected from Cu, Zn, and Fe), and As the oxide sintered body consisting of oxygen ions (O ^2- ), the atomic ratios of trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) are 0.2 ≦ ( In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.8, 0.1 ≤ (Fe ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.5, and ^{0.1 ≤ (X 2+) / {} (In 3 +) + (Fe 3 +) + (X 2 +)} ≤ 0.5 , and oxide-sintered body, which as an oxide semiconductor thin film having the same composition satisfying.

Description

Oxide sintered body and oxide semiconductor thin film {SINTERED OXIDE AND OXIDE SEMICONDUCTOR THIN FILM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oxide sinters and oxide semiconductor thin films useful for fabricating thin film transistors in display devices.

Oxide semiconductors are used as electrodes for solar cells and touch panels in addition to active layers of thin film transistors in display devices such as liquid crystal display devices, plasma display devices and organic EL display devices. Conventionally, as an oxide semiconductor, a transparent In-Ga-Zn-O system (hereinafter referred to as "IGZO system") is known (see Non-Patent Document 1), and tin (Sn) is added for intention of improving characteristics. There is also a report regarding the system (see Patent Documents 1 and 2). However, gallium (Ga), which is an essential component of these systems, is a rare element and, due to its high price and the like, has a large limitation in the industrial and large-scale use.

As a transparent oxide semiconductor not using Ga, In-Zn-O system (refer patent document 3), In-Zn-Sn-O system (refer patent document 4), and Zn-Sn-O system (patent document 5 See).

Japanese Laid-Open Patent Publication No. 2008-280216 Japanese Unexamined Patent Publication No. 2010-118407 Japanese Unexamined Patent Publication No. 2007-142195 Japanese Unexamined Patent Publication No. 2008-243928 Japanese Unexamined Patent Publication No. 2007-142196

 Nature 432, p 488-492, October 2004

Since the IGZO system substitute candidate materials described in the patent documents 3 to 5 are transparent semiconductors, the IGZO system has been narrowed only to a material system of transparent elements as oxides. However, an IGZO system is used as a channel layer of a transistor, and in most cases, transparency is not necessarily required. Therefore, the material system which is not transparent but can be used as the channel layer of the transistor has not been studied as an IGZO substitute material.

Therefore, an object of the present invention is to provide an oxide sintered body for producing an oxide semiconductor film which is a scarce resource and does not contain expensive gallium (Ga). Another object of the present invention is to provide an oxide semiconductor thin film having the same composition as the oxide sintered body.

In an aspect, the present invention provides trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) (wherein X is selected from Cu, Zn, and Fe). An oxide sintered body composed of one or more elements) and oxygen ions (O ^2- ), which include trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) Defense is 0.2 ≤ (In ^{3 +} ) / {(In ³ +) + (Fe ³ +) + (X ^{2 +} )} ≤ 0.8, 0.1 ≤ (Fe ^{3 +} ) / {(In ³ +) + (Fe ³ +) + (X ^{2 +} )}? 0.5, 0.1? (X ²⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )}?

In one embodiment, the oxide sintered body according to the present invention has a relative density of 98% or more.

In another embodiment, the oxide sintered body according to the present invention has a bulk resistance of 3 mΩ or less.

In another aspect, the present invention, trivalent indium ions (In 3 ⁺ ), trivalent iron ions (Fe ^{3 +} ), and divalent X ions (X ^{2 +} ) (where X is Cu, Zn, and Fe An oxide semiconductor thin film composed of one or more selected elements) and oxygen ions (O ^2- ), including trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X The atomic ^ratio of ²⁺ ) is 0.2 ≤ (In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.8, 0.1 ≤ (Fe ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≦ 0.5, and 0.1 ≦ (X ²⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≦ 0.5.

In one embodiment, the oxide semiconductor thin film according to the present invention is amorphous.

In another embodiment, the oxide semiconductor thin film according to the present invention has a carrier concentration of 10 ¹⁶ to 10 ¹⁸ cm ^-3 .

In yet another embodiment, the oxide semiconductor thin film according to the present invention has a mobility of 1 cm 2 / Vs or more.

In yet another aspect, the present invention is a thin film transistor including the oxide semiconductor thin film as an active layer.

In yet another aspect, the present invention is an active matrix driving display panel including the thin film transistor.

According to the present invention, an oxide sintered body for producing an oxide semiconductor film containing no gallium (Ga) can be provided. This oxide sintered compact is useful as a sputtering target. By sputter film-forming using this target, an oxide semiconductor film can be manufactured.

(Composition of Oxide Sintered Body)

Oxide sintered body which concerns on this invention is a trivalent indium ion (In3 ⁺ ), trivalent iron ion (Fe3 ⁺ ), and divalent X ion (X2 ⁺ ) (where X is chosen from Cu, Zn, and Fe). 1 or more types of elements), and oxygen ion ( ^O2- ). However, it is usually necessary to contain an element which is inevitably contained in the raw material refining process or an impurity element that is inevitably mixed in the oxide sintered manufacturing process, for example, up to about 10 ppm of each element. It is contained in the sintered compact which concerns on this invention.

Ratio of the number of atoms of trivalent indium ions (In ³⁺ ) to the total number of atoms of trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) (In ³⁺ ) It is preferable that / {(In3 ⁺ ) + (Fe3 ⁺ ) + (X2 ⁺ )} is 0.2-0.8. When (In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} is less than 0.2, the carrier concentration of the film becomes too small, the relative density at the time of target production becomes small, and the bulk resistance becomes high, Abnormal discharge during sputtering tends to occur. On the contrary, when (In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} exceeds 0.8, the carrier concentration of the film obtained by sputtering the target of the composition becomes too high, and is turned on as the channel layer of the transistor. Off ratio becomes small. ^{(In 3+) / {(In} 3+) + (Fe 3+) + (X 2 +)} is more preferably in the range of 0.25 to 0.6, more preferably in the range of 0.3 to 0.5.

Ratio of the number of atoms of trivalent iron ions (Fe ³⁺ ) to the total number of atoms of trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) (Fe ³⁺ ) It is preferable that / {(In3 ⁺ ) + (Fe3 ⁺ ) + (X2 ⁺ )} is 0.1-0.5. When (Fe ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} is less than 0.1, the carrier concentration of the film obtained by sputtering the target of the composition becomes too high, and the on-off ratio is small as the channel layer of the transistor. Lose. In ^{contrast, (Fe 3+) / {(} In 3+) + (Fe 3 +) + (X 2 +)} is when it exceeds 0.5, becomes too small, the film carrier density, relative density at the time of a target produced is reduced, the bulk The resistance is high, and abnormal discharge during sputtering is likely to occur. (Fe ^{+ 3)} / {(In ^{+ 3)} + (Fe ^{+ 3)} + (X ^{+ 2)},} is more preferably in the range of 0.15 to 0.4, more preferably in the range of 0.2 to 0.35.

The ratio of the total number of atoms of the metal element X to the total number of atoms of the trivalent indium ion (In ³⁺ ), the trivalent iron ion (Fe ³⁺ ), and the divalent X ion (X ²⁺ ) (X ²⁺ ) / {(In ³ +) + (Fe ³⁺ ) + (X ²⁺ )} is preferably 0.1 to 0.5. If (X ²⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} is less than 0.1, the carrier concentration of the film becomes too large. In ^{contrast, (X 2+) / {(} In 3+) + (Fe 3+) + (X 2 +)} is when it exceeds 0.5, the film becomes too small carrier concentration is, the smaller the relative density of the target during fabrication. (X ^{+ 2)} / {(In ^{+ 3)} + (Fe ^{+ 3)} + (X ^{+ 2)},} is more preferably in the range of 0.15 to 0.4, more preferably in the range of 0.2 to 0.35.

When iron ions (Fe ²⁺ ) are selected as the divalent X ions, only indium and iron are used as metal ions. However, there are divalent and trivalent kinds of iron ions, which are present in the oxide sintered body. Iron is a transition metal and can take a plurality of valences, and iron ions having different valences may exist in any compound. In a preferred embodiment of the present invention, the valence of iron ions is controlled in advance to form a compound. This makes it possible to obtain desired characteristics more easily.

Relative Density of Oxide Sintered Body

The relative density of the oxide sintered body has a correlation with the occurrence of joules on the surface during sputtering. When the oxide sintered body is low density, when the oxide sintered body is processed into a target and sputtered into a film, the lower oxide of indium is formed on the surface according to the progress of sputtering. The high-resistance part called a nodule of processus | protrusion generate | occur | produces, and it becomes easy to become a starting point of abnormal discharge in the subsequent sputter | spatter. In this invention, the relative density of an oxide sintered compact can be made into 98% or more by the titration of the appropriate range of a composition, and when it is this high density, there is little adverse effect by the nodule at the time of sputtering. The relative density is preferably 99% or more, and more preferably 99.5% or more.

In addition, the relative density of an oxide sintered compact can be calculated | required by dividing the density computed from the weight and external dimension after processing an oxide sintered compact in a predetermined shape by the theoretical density of the oxide sintered compact.

(Bulk Resistance of Oxide Sintered Body)

The bulk resistance of the oxide sintered body has a correlation with the extent to which abnormal discharge during sputtering is likely to occur. When the bulk resistance is high, abnormal discharge easily occurs during sputtering. In the present invention, the bulk resistance can be made 3 mΩcm or less by the appropriate range of the composition and the optimization of the manufacturing conditions, and there is little adverse effect on the occurrence of abnormal discharge during sputtering if the low bulk resistance is about this level. The bulk resistance is preferably 2.7 mΩcm or less, and more preferably 2.5 mΩcm or less.

In addition, a bulk resistance can be measured using a resistivity meter by the four probe method.

(Manufacturing Method of Oxide Sintered Body)

Examples of the oxide sintered body having various compositions according to the present invention include indium oxide (In ₂ O ₃ ), iron oxide (Fe ₂ O ₃ as a source of _trivalent iron, FeO as a source of divalent iron) and zinc oxide, for example. It can obtain by adjusting the compounding ratio of each raw material powder, such as (ZnO) and copper oxide (CuO), the conditions of particle size of a raw material powder, grinding time, sintering temperature, sintering time, and kind of sintering atmosphere gas.

It is preferable that raw material powder is an average particle diameter of 1-2 micrometers. When the average particle diameter exceeds 2 m, the density of the sintered compact becomes difficult to be improved. Therefore, the fine particle may be wetly pulverized or the like as the raw material powder alone or as a mixed powder, and the average particle size may be reduced to about 1 m. It is also effective to pre-fire for the purpose of improving the sinterability before wet mixed grinding. On the other hand, a raw material of less than 1 µm is difficult to obtain, and if too small, aggregation between particles easily occurs and difficult to handle, so the average particle diameter of the mixed powder before sintering is preferably 1 to 2 µm. Here, the average particle diameter of raw material powder points out the median diameter in the volume distribution measured by the laser diffraction type particle size distribution measuring apparatus. Moreover, in the range which can be interpreted as the equivalent of this invention, you may add other components which have an effect, such as improving a sinterability, without adversely affecting sintered compact characteristics other than predetermined raw material powder. It is preferable to shape | mold after mixing the raw material mixed powder after grinding | pulverization with a spray dryer, etc., to improve fluidity | liquidity and moldability. The shaping | molding can employ | adopt methods, such as normal pressurization and cold hydrostatic pressure pressurization.

Thereafter, the molded product is sintered to obtain a sintered body. It is preferable that sintering is sintered at 1400-1600 degreeC for 2 to 20 hours. Thereby, relative density can be made into 98% or more. If the sintering temperature is less than 1400 ° C., the density is hardly improved. On the contrary, if the sintering temperature is more than 1600 ° C., the composition of the sintered body may change due to volatilization of constituent elements or the like, causing a decrease in density due to void generation due to volatilization. Sometimes. Atmosphere can be used for the atmosphere gas at the time of sintering, the oxygen deficiency with respect to a sintered compact can be increased, and bulk resistance can be made small. However, depending on the composition of the sintered compact, even if the atmospheric gas is oxygen, a sufficiently high density sintered compact can be obtained.

(Sputter Tabernacle)

The oxide sintered body obtained as mentioned above can be made into the sputtering target by performing grinding | polishing, grinding | polishing, etc., and can form an oxide film which has the same composition as the said target by film-forming using this. At the time of processing, it is preferable to make surface roughness Ra into 5 micrometers or less by grinding a surface by methods, such as surface grinding. By making surface roughness small, the origin of nodule generation which causes abnormal discharge can be reduced.

The sputtering target is affixed to a backing plate made of copper or the like and installed in the sputtering device, and sputtered under suitable conditions such as an appropriate degree of vacuum, atmospheric gas, sputter power, and the like, thereby obtaining a film having substantially the same composition as the target.

In the case of the sputtering method, it is preferable that the attained vacuum degree in the chamber before film formation is 2 × 10 ^-4 Pa or less. If the pressure is too high, the mobility of the obtained film may decrease due to the influence of impurities in the residual atmosphere gas.

As the sputter gas, a mixed gas of argon and oxygen can be used. As a method of adjusting the oxygen concentration in the mixed gas, for example, using a gas cylinder of 100% argon and a gas cylinder of 2% oxygen in argon, the supply flow rate from each gas cylinder to the chamber is changed to the mass flow. It can implement by setting suitably. Here, the oxygen concentration in the mixed gas means oxygen partial pressure / (oxygen partial pressure + argon partial pressure), which is also the same as dividing the flow rate of oxygen by the sum of the flow rates of oxygen and argon. The oxygen concentration may be appropriately changed in accordance with the desired carrier concentration, but may typically be 1 to 3%, more typically 1 to 2%.

The total pressure of the sputter gas is about 0.3 to 0.8 Pa. If the total pressure is lower than this, plasma discharge becomes difficult to start, and plasma starts to become unstable even when started. In addition, when the total pressure is higher than this, problems such as slowing the film formation speed and adversely affecting productivity occur.

Sputter | spatter power forms into a film about 200-1200 W when target size is 6 inches. If the sputter power is too small, the film formation speed is small, the productivity is lowered. On the contrary, if the sputter power is too large, problems such as splitting of the target occur. 200-1200 W is 1.1 W / cm <2> -6.6 W / cm <2> in terms of sputter power density, and it is preferable to set it as 3.2-4.5 W / cm <2>. Here, the sputter power density is obtained by dividing the sputter power by the area of the sputtering target, and the power applied to the sputtering target is different because the power actually received by the sputtering target and the deposition rate are different depending on the sputtering target size even for the same sputtering power. It is an index for unifying expression.

As a method of obtaining a film from an oxide sintered body, a vacuum vapor deposition method, an ion plating method, a PLD (pulse laser deposition) method, etc. can also be used, but what is easy to use industrially is that it satisfies requirements such as large area, high speed film formation, and discharge stability. DC magnetron sputtering.

In sputter film formation, it is not necessary to heat the substrate. This is because relatively high mobility can be obtained without heating the substrate, and there is no need to add time or energy for raising the temperature. When sputter film-forming is performed without heating a board | substrate, the film obtained will become amorphous. However, since the same effect as the annealing after room temperature film-forming can be expected by heating a board | substrate, you may form into a film by board | substrate heating.

(Carrier concentration of oxide film)

The carrier concentration of the oxide film has a correlation with various characteristics of the transistor when the film is used for the channel layer of the transistor. If the carrier concentration is too high, a small leakage current is generated even when the transistor is turned off, and the on-off ratio is lowered. On the other hand, if the carrier concentration is too low, the current flowing through the transistor is small. In the present invention, the carrier concentration of the oxide film can be set to 10 ¹⁶ to 10 ¹⁸ cm ^-3 depending on the proper range of the composition, etc., and if it is this range, a transistor having good characteristics can be manufactured.

(Mobility of Oxide Film)

Mobility is one of the most important characteristics among the transistors, and it is preferable that the oxide semiconductor is 1 cm 2 / Vs or more, which is the mobility of amorphous silicon, which is a competition material used as the channel layer of the transistor. Basically, the higher the mobility, the better. The oxide film according to the present invention may have a mobility of 1 cm 2 / Vs or more, preferably 3 cm 2 / Vs or more, and more preferably 5 cm 2 / Vs or more, depending on an appropriate range of composition. It can have This results in superior characteristics than amorphous silicon, resulting in higher industrial applicability.

The oxide semiconductor thin film according to the present invention can be used, for example, as an active layer of a thin film transistor. In addition, the thin film transistor obtained by using the above manufacturing method can be used as an active element and used in an active matrix drive display panel.

Example

Examples of the present invention will now be described in conjunction with comparative examples, which are provided for a better understanding of the present invention and its advantages and are not intended to be limiting. Therefore, this invention includes all the aspects or modifications other than an Example within the scope of the technical idea of this invention.

In the following Examples and Comparative Examples, the physical properties of the sintered compact and the film were measured by the following method.

(A) Relative density of sintered body

It calculated | required from the measurement result of a weight and an external dimension, and the theoretical density from a structural element.

(B) Bulk resistance of sintered body

It was calculated | required by the four probe method (JIS K7194) using the model Σ-5 + apparatus manufactured by NPS (NPS).

(C) Composition of sintered body and film

It was calculated | required by ICP (High Frequency Inductively Coupled Plasma) analysis using the model SPS3000 by SII Nanotechnology.

(D) thickness

It calculated | required using the step | diometer (made by Veeco, model Dektak8 STYLUS PROFILER).

(E) Carrier Concentration and Mobility of Membrane

The glass substrate formed into a film was cut out to about 10 mm in width | variety, the indium electrode was attached to the four corners, it was set in the hall measuring apparatus (Toyo Technica make, model Resitest8200), and it measured.

(F) the crystalline or amorphous structure of the membrane;

Crystallinity was determined using the Rigaku Corporation RINT-1100 X-ray diffraction apparatus. If no significant peak above background level was recognized, it was determined to be amorphous.

(G) Average particle size of powder

The average particle diameter was measured by SALD-3100 by Shimadzu Corporation.

&Lt; Example 1 >

Indium oxide (In ₂ O ₃ ) powder (average particle diameter 1.0 µm), iron oxide (Fe ₂ O ₃ ) powder (average particle diameter 1.0 µm), and zinc oxide (ZnO) powder (average particle diameter 1.0 µm) It weighed so that (In: Fe: Zn) might be 0.4: 0.3: 0.3, and it wet-pulverized and grind | pulverized. The average particle diameter of the mixed powder after grinding was 0.8 µm. After this mixed powder was granulated with a spray dryer, the mixed powder was filled into a mold and pressure-molded, followed by sintering at a high temperature of 1450 ° C. for 10 hours in an air atmosphere. The obtained sintered compact was processed into the disk shape of diameter 6 inch and 6 mm in thickness, it was ground-grinded, and it was set as the sputtering target. About the said target, it was 99.6% when the relative density was computed from the measurement result and theoretical density of a weight and an external dimension. In addition, the bulk resistance of the sintered compact measured by the probe probe method was 2.0 m (ohm) cm. As a result of the sintered compact composition analysis by ICP (high frequency inductively coupled plasma) analysis method, it was In3 ⁺ : Fe3 ⁺ : Zn2 ⁺ = 0.4: 0.3: 0.3 (atomic ratio).

The sputtering target produced above was affixed on the copper backing plate using indium as a solder | pewter, and it installed in the DC magnetron sputtering apparatus (SPL-500 sputtering apparatus made by ANELVA). The glass substrate used Corning 1737, and sputter | spatter conditions were: substrate temperature: 25 degreeC, reaching pressure: 1.2 * 10 <^-4> Pa, atmospheric gas: Ar 99%, oxygen 1%, sputter pressure (total pressure): 0.5 Pa, A thin film having a film thickness of about 100 nm was produced with an input power of 500 W. At the time of film-forming of the oxide semiconductor thin film, abnormal discharge was not recognized.

As a result of performing the hole measurement of the obtained film | membrane, carrier density 5.2 * 10 <^17> cm <^-3> and mobility 5.0cm <2> / Vs were obtained. As a result of the film composition analysis by ICP (high frequency inductively coupled plasma) analysis, In ³⁺ : Fe ³⁺ : Zn ²⁺ = 0.4: 0.3: 0.3 (atomic ratio). As a result of the measurement by X-ray diffraction, the film was amorphous.

<Example 2-Example 12>

An oxide sintered body and an oxide semiconductor thin film were obtained in the same manner as in Example 1 except that the composition ratio of the raw material powders was set to the respective values shown in Table 1. Each relative density, bulk resistance, carrier concentration, and mobility were as listed in Table 1. In addition, the composition of the sintered compact and the film | membrane was the same as the composition ratio of raw material powder, respectively.

In addition, the indium oxide as a source of In ^{3 +} (In ₂ O ₃₎ powder (average particle size of 1.0 ㎛), iron oxide as a source of Fe ^{3 +} (Fe ₂ O ₃₎ powder (average particle size of 1.0 ㎛), Zn source of ²⁺ Zinc oxide (ZnO) powder (average particle diameter 1.0 mu m) was used as a source of Cu ²⁺ (CuO) powder (average particle diameter 1.0 mu m), and iron oxide (FeO) powder (average particle size 1.0 mu m) was used as a source of Fe ²⁺ .

<Comparative Example 1-Comparative Example 10>

 An oxide sintered body and an oxide semiconductor thin film were obtained in the same manner as in Example 1 except that the composition ratio of the raw material powders was set to the respective values shown in Table 1. Each relative density, bulk resistance, carrier concentration, and mobility were as shown in Table 1. In addition, the composition of the sintered compact and the film | membrane was the same as the composition ratio of raw material powder, respectively.

As can be seen from the results shown in Table 1, the oxide sintered body according to the embodiment of the present invention has a high relative density and a small bulk resistance. In addition, when the oxide sintered body according to the present invention is formed as a sputtering target, an oxide semiconductor thin film having an appropriate carrier concentration and high mobility is obtained.

Claims (9)

Trivalent indium ion (In ^{3 +)} and trivalent iron ions (Fe ^{3 +)} and divalent X ion (X ^{2 +)} (stage, X is at least one element selected from Cu, Zn, and Fe And an atomic ratio of trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ), respectively, as an oxide sintered body composed of oxygen ions (O ²⁻ ), 0.2 ≤ (In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.8, 0.1 ≤ (Fe ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.5, and ^{0.1 ≤ (X 2 +) /} {(In 3 +) + (Fe 3 +) + (X 2 +)} ≤ 0.5, the oxide-sintered body satisfying. The method of claim 1,
Oxide sintered compact whose relative density is 98% or more. 3. The method according to claim 1 or 2,
Oxide sintered compact whose bulk resistance is 3 m (ohm) or less. Trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), divalent X ions (X ²⁺ ) (where X represents at least one element selected from Cu, Zn, and Fe), and In the oxide semiconductor thin film composed of oxygen ions (O ^2- ), the atomic ratio of trivalent indium ions (In ³⁺ ), trivalent iron ions (Fe ³⁺ ), and divalent X ions (X ²⁺ ) is 0.2 ≦ (In ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.8, 0.1 ≤ (Fe ³⁺ ) / {(In ³⁺ ) + (Fe ³⁺ ) + (X ²⁺ )} ≤ 0.5, 0.1 ≤ An oxide semiconductor thin film satisfying (X ^{2 +} ) / {(In ^{3 +} ) + (Fe ^{3 +} ) + (X ^{2 +} )} ≤ 0.5. The method of claim 4, wherein
An amorphous, oxide semiconductor thin film. The method according to claim 4 or 5,
An oxide semiconductor thin film having a carrier concentration of 10 ¹⁶ to 10 ¹⁸ cm ^-3 . 7. The method according to any one of claims 4 to 6,
An oxide semiconductor thin film having a mobility of 1 cm 2 / Vs or more. The thin film transistor provided with the oxide semiconductor thin film as described in any one of Claims 4-7 as an active layer. An active matrix drive display panel comprising the thin film transistor according to claim 8.