KR101324830B1 - Sintered oxide and oxide semiconductor thin film - Google Patents

Abstract

[In^{3 +}]/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.8, 0.1

[X^{2 +}]/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5, 및 0.1

{[Y^{3 +}]＋[Z^{4 +}]}/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5 를 만족하는 산화물 소결체.An object of the present invention is to provide an oxide sintered body for producing an oxide semiconductor film containing no expensive gallium (Ga) and zinc (Zn) which has problems in film stability. Another object is to provide an oxide semiconductor thin film having the same composition as the oxide sintered body. Trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ) (where X represents at least one element selected from Mg, Ca, Co, and Mn), and trivalent metal ions (Y ³⁺⁾ (where, Y is one element selected from among B, Y, represents at least one element selected from Cr) or tetravalent metal ions (Z ^{+ 4)} (where, Z is Si, Ge, Ti, Zr The above elements), oxygen ions (O ^{2 −} ), trivalent indium ions (In ^{3 +} ), divalent metal ions (X ^{2 +} ), trivalent metal ions (Y ^{3 +} ), and 4 Atomic ratios of valence metal ions (Z ^{4 +} ) are respectively 0.2

[In ^{3 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.8, 0.1

[X ^{2 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.5, and 0.1

{[Y ^{3 +} ] + [Z ^{4 +} ]} / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

Oxide sintered compact which satisfy | fills 0.5.

Description

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

The present invention relates to an oxide sintered body and an oxide semiconductor thin film useful for manufacturing a thin film transistor in a display device.

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 a system in which tin (Sn) is added for intention of improving characteristics. There is also a report (see Patent Documents 1 and 2). However, gallium (Ga), which is an essential component of such a system, is a rare element, and there is a big limitation in using it in an industrial mass for reasons such as high price.

Examples of transparent oxide semiconductors that do not use Ga include In-Zn-O based materials (see Patent Document 3), In-Zn-Sn-O based materials (see Patent Document 4), and Zn- ).

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

 Nature 432, p488-492, October 2004

The oxide semiconductors described in Patent Documents 3 to 5 do not use Ga, which is an essential component of the IGZO system, and are advantageous in terms of manufacturing cost. However, problems such as poor environmental stability such as a change in resistivity over time remain. . In addition, zinc (Zn), which is another essential component of the IGZO system, is an element that tends to be volatilized, and the density of the sintered compact due to volatilization at the time of manufacture of the sintered compact, the deviation from the target composition due to volatilization at the time of sputter deposition, and the resistivity of the film It is becoming a deterrent to membrane stability, such as changes over time.

Then, an object of this invention is to provide the oxide sinter for oxide semiconductor film manufacture which is a scarce resource, does not contain expensive gallium (Ga) and zinc (Zn) which is easy to volatilize and has a problem of film stability. Another object of the present invention is to provide an oxide semiconductor thin film having the same composition as that of the oxide-sintered body.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventor uses predetermined | prescribed divalent metal as a substitute of zinc (Zn) which is easy to volatilize, and predetermined trivalent as a replacement of gallium (Ga) which is a rare and expensive element. Or by using a tetravalent metal and adjusting these atomic ratios, the conditions for producing the sintered body and the film, and the like, to obtain an oxide sintered body for producing an oxide semiconductor film and an oxide semiconductor thin film containing no gallium (Ga) and zinc (Zn). Figured out.

[In³⁺]/{[In³⁺]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.8, 0.1

[X^{2 +}]/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5, 및 0.1

{[Y^{3 +}]＋[Z^{4 +}]}/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5 를 만족하는 산화물 소결체이다.The present invention completed based on the above findings, in one aspect, trivalent indium ions (In ^{3 +} ) and divalent metal ions (X ^{2 +} ) (where X is selected from Mg, Ca, Co and Mn) Trivalent metal ions (Y ³⁺ ) (where Y represents at least one element selected from B, Y and Cr) or tetravalent metal ions (Z ⁴⁺ ) ( However, Z represents at least one element selected from Si, Ge, Ti, and Zr, and oxygen ions (O ^2- ), trivalent indium ions (In ³⁺ ), and divalent metal ions (X ²⁺ ), trivalent metal ions (Y ^{3 +} ), and tetravalent metal ions (Z ^{4 +} ) have an atomic ratio of 0.2, respectively.

[In ³⁺ ] / {[In ³⁺ ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.8, 0.1

[X ^{2 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.5, and 0.1

{[Y ^{3 +} ] + [Z ^{4 +} ]} / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

It is an oxide sintered body which satisfies 0.5.

In one Embodiment, the oxide sintered compact which concerns on this invention is 98% or more in relative density.

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

[In^{3 +}]/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.8, 0.1

[X^{2 +}]/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5, 및 0.1

{[Y^{3 +}]＋[Z^{4 +}]}/{[In^{3 +}]＋[X^{2 +}]＋[Y^{3 +}]＋[Z^{4 +}]}

0.5 를 만족하는 산화물 반도체 박막이다.In another aspect of the present invention, trivalent indium ions (In ³⁺ ) and divalent metal ions (X ²⁺ ) (where X represents at least one element selected from Mg, Ca, Co, and Mn) ) And trivalent metal ions (Y ³⁺ ) (where Y represents at least one element selected from B, Y and Cr) or tetravalent metal ions (Z ⁴⁺ ) (where Z is Si and Ge , At least one element selected from Ti and Zr), oxygen ions (O ^2- ), trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ), and trivalent metals. The atomic ^{ratio of the} ions (Y ³⁺ ) and the tetravalent metal ions (Z ^{4 +} ) is 0.2, respectively.

[In ^{3 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.8, 0.1

[X ^{2 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

0.5, and 0.1

{[Y ^{3 +} ] + [Z ^{4 +} ]} / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]}

It is an oxide semiconductor thin film which satisfy | fills 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 one Embodiment with an oxide semiconductor thin film which concerns on this invention, mobility is 1 cm <2> / Vs or more.

According to another aspect of the present invention, there is provided a thin film transistor including the oxide semiconductor thin film as an active layer.

According to another aspect of the present invention, there is provided an active matrix driving display panel including the thin film transistor.

According to the present invention, it is possible to provide an oxide sintered body for producing an oxide semiconductor film which is a scarce resource, does not contain expensive gallium (Ga) and zinc (Zn), which is easily volatilized and has a problem in film stability. According to the present invention, an oxide semiconductor thin film having the same composition as that of the oxide-sintered body can be provided.

(Composition of oxide-sintered body)

Oxide sintered body which concerns on this invention is trivalent indium ion (In3 ⁺ ) and divalent metal ion (X2 ⁺ ) (where X represents 1 or more types of elements chosen from Mg, Ca, Co, and Mn) And trivalent metal ions (Y ³⁺ ) (where Y represents at least one element selected from B, Y and Cr) or tetravalent metal ions (Z ⁴⁺ ) (where Z is Si, Ge, At least one element selected from Ti and Zr), and oxygen ions (O ^2- ). However, the concentration degree which inevitably contains the element which is inevitably contained in the refinement | purification process of the raw material which can be obtained normally, and the impurity element inevitably mixed in the process of manufacturing an oxide sintered body, for example, to about 10 ppm of each element What contains is contained in the sintered compact which concerns on this invention.

Trivalent indium ion (In ^3+), 2-valent metal ion (X ^2+), metal trivalent ions (Y ^3+), and tetravalent metal ions, trivalent indium ion to the total number of atoms of (Z ^{+ 4)} The atomic ratio [In ^{3 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]} of (In ^{3 +} ) is 0.2 to 0.8. When [In ^{3 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]} is less than 0.2, the relative density at the time of target manufacture becomes small and bulk resistance becomes high. Abnormal discharge during sputtering is likely to occur. When [In ³⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]} exceeds 0.8, the carrier concentration of the film obtained by sputtering the target of the composition is excessive. It becomes high, and the on-off ratio becomes small for the channel layer of a transistor. [In ³⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}, More preferably, it is the range of 0.25-0.6, More preferably, it is 0.3- It is in the range of 0.5. Where [In ³⁺ ] is the number of atoms of indium, [X ²⁺ ] is the number of atoms of divalent metal ions (X ²⁺ ), and [Y ³⁺ ] is the number of atoms of trivalent metal ions (Y ³⁺ ) And [Z ⁴⁺ ] represent the number of atoms of the tetravalent metal ion (Z ⁴⁺ ), respectively.

Trivalent indium ion (In ^3+), a bivalent metal ion (X ^2+), trivalent metal ions (Y ^3+), and tetravalent metal ions, a divalent metal ion to the total number of atoms of (Z ^{+ 4)} (X ^{+ 2)} of the atomic ratio [X ^{+ 2]} / {[in ^{+ 3]} + [X ^{+ 2]} + [Y ^{+ 3]} + ^{[4 +} Z]} is from 0.1 to 0.5. When [X ^{2 +} ] / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]} is less than 0.1, the carrier concentration of the film obtained by sputtering a target having the composition becomes too high. As a result, the on-off ratio becomes small in the channel layer of the transistor. When [X ²⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]} exceeds 0.5, the relative density at the time of target fabrication becomes small and bulk resistance becomes It becomes high, and abnormal discharge at the time of sputtering becomes easy to generate | occur | produce. [X ²⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}, More preferably, it is the range of 0.15-0.4, More preferably, it is 0.2- 0.35.

Trivalent metal ions with respect to the total number of atoms of trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ), trivalent metal ions (Y ³⁺ ), and tetravalent metal ions (Z ⁴⁺ ) Total atomic ^{ratio of} (Y ³⁺ ) and tetravalent metal ions (Z ^{4 +} ) {[Y ^{3 +} ] + [Z ^{4 +} ]} / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]} is 0.1-0.5. If {[Y ^{3 +} ] + [Z ^{4 +} ]} / {[In ^{3 +} ] + [X ^{2 +} ] + [Y ^{3 +} ] + [Z ^{4 +} ]} is less than 0.1, the target of the composition is sputtered. The carrier concentration of the film thus obtained becomes too high, and the on-off ratio becomes small in the channel layer of the transistor. When {[Y ³⁺ ] + [Z ⁴⁺ ]} / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]} exceeds 0.5, the opponent at the time of target preparation Density becomes small, bulk resistance becomes high, and abnormal discharge at the time of sputtering becomes easy to generate | occur | produce. {[Y ³⁺ ] + [Z ⁴⁺ ]} / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]} is more preferably in the range of 0.15 to 0.4 More preferably, it is the range of 0.2-0.35.

(Relative density of oxide-sintered body)

The relative density of the oxide sintered body has a correlation with the generation of nodules on the surface during sputtering. When the oxide sintered body has a low density, when the oxide sintered body is processed into a target and sputtered into a film, a high-resistance part called a protrusion nodule, which is a lower oxide of indium, is formed on the surface as the sputter film is formed. Is likely to be the starting point of the abnormal discharge. In this invention, the relative density of an oxide sintered compact can be 98% or more according to the appropriate range of a composition and the optimization of a manufacturing condition, and if it is this high density, there is hardly an adverse influence by the nodule at the time of sputtering. The relative density is preferably 99% or more, and more preferably 99.5% or more.

The relative density of the oxide-sintered body can be obtained by dividing the density calculated from the weight and the external dimension after the oxide-sintered body has been processed into the predetermined shape by the theoretical density of the oxide-sintered body.

(Bulk resistance of oxide-sintered body)

The bulk resistance of the oxide sintered body has a correlation with the occurrence of abnormal discharge during sputtering. When the bulk resistance is high, abnormal discharge easily occurs during sputtering. In the present invention, the bulk resistance can be 3 mΩcm or less depending on the proper range of the composition and the optimization of the manufacturing conditions. If the low bulk resistance is about this level, there is little adverse effect on the occurrence of abnormal discharge during sputtering. 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)

Oxide sinters of various compositions according to the present invention are, for example, conditions such as compounding ratios of raw material powders such as indium oxide and magnesium oxide as raw materials, particle diameters of raw material powders, grinding time, sintering temperature, sintering time, types of sintering atmosphere gases, and the like. Can be obtained by adjusting

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, wet grinding and the like may be performed as the raw material powder alone or as a mixed powder, and the average particle diameter may be reduced to about 1 m. It is also effective to calcinate for the purpose of improving the sinterability before wet mixed grinding. On the other hand, raw materials of less than 1 µm are difficult to obtain, and when too small, aggregation between particles tends to occur, making it difficult to handle them. Here, the average particle diameter of raw material powder points out the value measured by the laser diffraction measuring method. It is preferable to shape | mold after granulating the raw material mixed powder after grinding | pulverization with a spray dryer etc., to improve fluidity | liquidity and moldability. The molding can be carried out by a conventional method such as press molding or cold isostatic pressing.

Thereafter, the molded product is sintered to obtain a sintered body. The sintering is preferably performed at 1400 to 1600 ° C for 2 to 20 hours. As a result, the relative density can be set to 98% or more. If the sintering temperature is less than 1400 ° C., the density is hardly improved, and if the sintering temperature is more than 1600 ° C., the composition of the sintered body may change due to volatilization of constituent elements, or may cause a decrease in density due to the generation of voids due to volatilization. do. Atmosphere can be used for the atmospheric gas at the time of sintering, and a high density sintered compact can be obtained by the effect of volatilization suppression from a sintered compact. 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 Deposition)

The oxide sintered body obtained as mentioned above can be used as a 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 a process, it is preferable to make surface roughness Ra into 5 micrometers or less by grinding a surface by methods, such as surface grinding. By reducing the surface roughness, the origin of nodule generation that causes abnormal discharge can be reduced.

The sputtering target is affixed to a backing plate made of copper or the like, provided in a 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 excessively high, there is a possibility that the mobility of the obtained film is lowered due to the influence of the impurities in the residual atmosphere gas.

A mixed gas of argon and oxygen may be used as the sputter gas. 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), and is also the same as dividing the flow rate of oxygen by the sum of the flow rates of oxygen and argon. What is necessary is just to change oxygen concentration suitably according to desired carrier density | concentration, Typically, it can be 1-3%, More typically, it can be 1-2%.

The total pressure of the sputter gas is about 0.3 to 0.8 kPa. If the total pressure is lower than this, plasma discharge is less likely to occur, and the plasma becomes unstable even if it occurs. Moreover, when the total pressure is higher than this, the film forming speed will be slow, which may adversely affect productivity.

Sputter | spatter power is formed into a film about 200-1200 W when target size is 6 inches. If the sputter power is too small, the deposition rate is small, the productivity is lowered. On the contrary, if the sputter power is too large, problems such as cracking of the target occur. 200-1200 W is 1.1 W / cm <2> -6.6 W / cm <2> in conversion with sputter power density, 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 from the sputtering target even when the same sputtering power actually differs according to the sputtering target size, and the film formation speed is different. It is an index for unifying expression.

As a method of obtaining a film from the oxide sintered body, a vacuum vapor deposition method, an ion plating method, a PLD (pulse laser deposition) method, or the like may be used. However, it is easy to use industrially to satisfy requirements such as large area, high speed film formation, and discharge stability. DC magnetron sputtering.

At the time of 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 the substrate is sputtered without heating, the resulting film becomes amorphous. However, by heating the substrate, it is expected that the same effect as annealing after the room temperature film formation can be obtained.

(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 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 becomes small. In the present invention, the carrier concentration of the oxide film can be 10 ¹⁶ to 10 ¹⁸ cm ^-3 depending on the appropriate range of the composition, etc., and a transistor having good characteristics can be produced in this range.

(Mobility of oxide film)

The 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, a competitive 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 the composition. May have degrees. Thereby, it becomes the characteristic superior to amorphous silicon, and the industrial application possibility becomes high.

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

Example

Although the Example of this invention is shown with a comparative example below, these Examples are provided in order to understand this invention and its advantage better, and it does not intend that invention is limited. 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, physical properties of the sintered body and the film were measured by the following methods.

(A) Composition of sintered body and membrane

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

(B) Relative density of sintered body

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

(C) Bulk resistance of the sintered body

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

(D) Thickness

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

(E) Carrier concentration and mobility of the film

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

(F) Crystals or amorphous structures of membranes

Crystallinity was determined using the Rigaku Corporation RINT-1100 X-ray diffraction apparatus. This X-ray diffraction judged it to be amorphous with no significant peak observed above the background level.

(G) Average particle size of powder

The average particle diameter of the powder was measured by SALD-3100 manufactured by Shimadzu Corporation.

&Lt; Example 1 &gt;

The indium oxide powder (average particle diameter 1.0 mu m), silicon oxide powder (average particle diameter 1.0 mu m), and magnesium oxide powder (average particle diameter 1.0 mu m) have an atomic ratio of the metal element (In: Si: Mg) of 0.4: 0.3: 0.3 Weighed as desired, and the wet mixed grinding was performed. The average particle diameter of the mixed powder after grinding | pulverization was 0.8 micrometers. After this mixed powder was granulated with a spray dryer, it filled into a metal mold | die and pressure-molded, and it sintered for 10 hours at 1450 degreeC high temperature in air | atmosphere. The obtained sintered compact was processed into the disk shape of diameter 6 inches and thickness 6mm, and it was set as the sputtering target. It was 99.5% when the relative density was computed from the measurement result and theoretical density of the weight and an external dimension with respect to the said target. Moreover, the bulk resistance of the sintered compact measured by the probe probe method was 2.2 m (ohm) cm.

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, The sputtering conditions, substrate temperature: 25 ℃, pressure reached: 1.2 × 10 ^-4 Pa, atmosphere 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. No abnormal discharge was observed during the film formation of the oxide semiconductor thin film.

Hole measurement of the obtained film was carried out to determine the carrier concentration and mobility. Moreover, as a result of the measurement by X-ray diffraction, the said 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 of the 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. No abnormal discharge was observed during the film formation of these oxide semiconductor thin films.

<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 of the 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 the raw material powder, respectively.

Examples of Examples 1 to 12, divalent metal ions (X ^{2 +)} Mg and Ca to, the B as an example of the trivalent metal ion (Y ^{3 +),} 4-valent metal ion (Z ^{4 +)} as an example of the An oxide sintered body containing Si was produced. However, bivalent a Co or Mn as the metal ion (X ^{2 +),} 3-valent metal ion to Y or Cr as (Y ^{3 +),} a tetravalent metal ion (Z ^{4 +)} containing Ge, Ti or Zr Even if an oxide sintered body is produced, since the valence uses the same ion, respectively, it is judged to have the same effect as Examples 1-12.

In Examples 1-12, carrier density | concentration was in the range of 10 <^16> -10 <^18> cm <^-3> , and mobility was 1 cm <2> / Vs or more.

On the other hand, in Comparative Examples 1, 4 and 6 to 10, the carrier concentration was less than 10 ¹⁶ cm ^-3 .

In Comparative Examples 1, 4, 6, 8, and 10, the mobility was less than 1 cm 2 / Vs.

In Comparative Examples 2, 3, and 5, the carrier concentration was more than 10 ¹⁸ cm ^-3 .

Claims (9)

Trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ) (where X represents at least one element selected from Mg, Ca, Co, and Mn), and trivalent metal ions (Y ³⁺ ) (wherein Y represents one or more elements selected from B, Y and Cr) or tetravalent metal ions (Z ⁴⁺ ) (where Z represents one species selected from Si, Ge, Ti, and Zr) Above elements), and oxygen ions (O ^2- ),
Atomic ratios of trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ), trivalent metal ions (Y ³⁺ ), and tetravalent metal ions (Z ⁴⁺ ), respectively,
0.2

[In ³⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.8,
0.1

[X ²⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.5, and
0.1

{[Y ³⁺ ] + [Z ⁴⁺ ]} / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.5,
Oxide sintered compact whose relative density is 98% or more. delete The method of claim 1,
And the bulk resistance is 3 m? Or less. Trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ) (where X represents at least one element selected from Mg, Ca, Co, and Mn), and trivalent metal ions (Y ³⁺ ) (wherein Y represents one or more elements selected from B, Y and Cr) or tetravalent metal ions (Z ⁴⁺ ) (where Z represents one species selected from Si, Ge, Ti, and Zr) Above elements), and oxygen ions (O ^2- ),
Atomic ratios of trivalent indium ions (In ³⁺ ), divalent metal ions (X ²⁺ ), trivalent metal ions (Y ³⁺ ), and tetravalent metal ions (Z ⁴⁺ ), respectively,
0.2

[In ³⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.8,
0.1

[X ²⁺ ] / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.5, and
0.1

{[Y ³⁺ ] + [Z ⁴⁺ ]} / {[In ³⁺ ] + [X ²⁺ ] + [Y ³⁺ ] + [Z ⁴⁺ ]}

0.5,
The carrier concentration is 10 ¹⁶ ~ 10 ¹⁸ ㎝ ^-3 of the oxide semiconductor thin film. 5. The method of claim 4,
Amorphous, oxide semiconductor thin film. delete The method according to claim 4 or 5,
An oxide semiconductor thin film having a mobility of 1 cm 2 / Vs or more. A thin film transistor comprising the oxide semiconductor thin film according to claim 4 or 5 as an active layer. An active matrix drive display panel comprising the thin film transistor according to claim 8.