WO2023063774A1 - Molybdenum oxide-based sintered body, and sputtering target and oxide thin film comprising same - Google Patents

Abstract

The present invention provides an oxide sintered body comprising a molybdenum oxide as a main component, a sputtering target comprising the sintered body, and an oxide thin film formed therefrom. The present invention can improve sinterability and secure high-density characteristics at the same time, even when pressureless sintering is performed, by adding a specific (metalloid or) metal oxide to a sinter-resistant molybdenum oxide and a niobium oxide in a predetermined range.

Description

Molybdenum oxide-based sintered body, sputtering target and oxide thin film including the same

The present invention relates to an oxide sintered body containing molybdenum oxide as a main component, a sputtering target including the sintered body, and an oxide thin film formed therefrom, and more particularly, to manufacturing a sputtering target used in TFT structures of LCD and OLED. It relates to a molybdenum oxide-based sintered body with improved sinterability and density characteristics by adding a specific (semi)metal oxide in a predetermined range, a sputtering target, and an oxide thin film formed therefrom.

In general, flat panel displays (“FPD”), touch screen panels, solar cells, light emitting diodes (“LEDs”), and organic light emitting diodes (“OLEDs”) have low reflectivity. A conductive thin film is used.

As a material for this, indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) (“ITO”) is representative, and the ITO composition is used to form a conductive thin film having high visible light transmittance and electrical conductivity. Although these ITO compositions have excellent low-reflectance performance, they are not economically viable, so research on materials that replace all or part of indium oxide continues.

However, the area of interest in these studies is the low reflectivity of thin films formed through target materials, and it is necessary to consider the characteristics of chemical resistance and heat resistance that can increase the reliability of thin films for long-term use.

On the other hand, molybdenum oxide is a difficult-to-sinter material that is difficult to sinter itself. In this way, when using a molybdenum oxide-based ceramic material that is difficult to sinter and has a low density, it is difficult to construct a high-density (eg, 90% or more relative density) target, and back depo. And foreign matter is generated due to the generation of nodules, which inevitably leads to deterioration of physical properties of the thin film.

[Prior art literature]

(Patent Document 1) Republic of Korea Patent Publication No. 10-2020-0069314

The present invention has been made to solve the above problems, and by adding a specific (semi)metal oxide in a predetermined range to difficult-to-sinterable molybdenum oxide, which is a main raw material, sinterability is improved and high density can be secured even when sintered in a non-pressurized state. It is a technical task to provide a novel molybdenum oxide-based sintered body that can be used, a sputtering target including the sintered body, and an oxide thin film formed therefrom.

Other objects and advantages of the present invention can be more clearly described by the following detailed description and claims.

In order to achieve the above technical problem, the present invention MoO ₂ And MoO ₃ Molybdenum oxide containing at least one of (M1); niobium oxide (M2); and a metal oxide (M3) containing at least one kind of alkaline earth metal, and provides an oxide sintered body containing at least 70% by weight of molybdenum oxide (M1) based on the total weight of the sintered body.

For example, the metal oxide M3 may include a first metal oxide M3-1 including at least one of Ca and Mg.

For one embodiment of the present invention, the first metal oxide (M3-1) may include at least one selected from the group consisting of CaCO ₃ and MgO.

For one embodiment of the present invention, the metal oxide (M3) may include a first metal oxide (M3-1); and a second metal oxide (M3-2) containing at least one metal selected from the group consisting of Co, Si, Y, and Ga.

For example, the second metal oxide (M3-2) may include at least one selected from the group consisting of Co ₃ O ₄ , SiO ₂ , Y ₂ O ₃ , and Ga ₂ O ₃ . there is.

For one embodiment of the present invention, the metal oxide (M3) may be included in an amount greater than 0 wt% and less than 10.0 wt% based on 100 wt% of the sintered body.

In one embodiment of the present invention, the molybdenum oxide (M1) and the niobium oxide (M2) are included in 90.0% by weight or more and less than 100% by weight based on 100% by weight of the oxide sintered body, and the molybdenum oxide (M1 ) and the niobium oxide (M2) may be in a weight ratio of 50:50 to 90:10.

For one embodiment of the present invention, the oxide sintered body, molybdenum oxide (M1); niobium oxide (M2); And the metal oxide (M3) may be mixed and molded, and then non-pressure sintered.

For one embodiment of the present invention, the oxide sintered body may have a specific resistance of 1×10 ^-2 Ωcm or less and a relative density of 80% or more.

In addition, the present invention provides a sputtering target comprising the above-mentioned pressure-free sintered body.

In addition, the present invention provides an oxide thin film formed from the sputtering target.

According to an embodiment of the present invention, by adding a (semi)metal oxide containing a specific element to a difficult-to-sinterable molybdenum oxide in a predetermined range, it is possible to improve the sinterability of the molybdenum oxide sintered body and secure high density even under no pressure. can

Accordingly, the molybdenum oxide-based sintered body and sputtering target according to the present invention can be usefully applied to forming electrodes or wires used in TFT structures of LCDs and OLEDs.

Effects according to the present invention are not limited by the contents exemplified above, and more diverse effects are included in the present specification.

1 is a photograph showing the structure change of a sintered body according to the heat treatment temperature using the molded body of Example 9 to which a metal oxide (M3) is added.

2 is a photograph showing the structure change of the sintered body according to the heat treatment temperature using the molded body of Comparative Example 1 to which no metal oxide (M3) is added.

3 is a SEM photograph showing the fractured surface of the powder structure of the mixed raw materials, the structure of the non-pressurized sintered body prepared in Example 9, and the structure of the pressed sintered body prepared in Comparative Example 5, respectively.

4 is a SEM photograph showing the polished surface of the structure of the non-pressurized sintered body prepared in Example 9 and the structure of the pressurized sintered body prepared in Comparative Example 5, respectively.

5 is a graph showing the relative density according to the sintering temperature of the non-pressurized sintered body prepared in Examples 1 to 6.

6 is a graph showing the relative density according to the sintering temperature of the non-pressurized sintered body prepared in Examples 7 to 12.

7 is a graph showing the relative density according to the sintering temperature of the non-pressurized sintered body prepared in Examples 13 to 17.

8 is a graph showing the relative density according to the sintering temperature of the sintered bodies prepared in Comparative Examples 1 to 4.

9 is a graph showing the change in shrinkage according to the sintering temperature of the non-pressurized sintered body prepared in Examples 1 to 6.

10 is a graph showing the change in shrinkage according to the sintering temperature of the non-pressurized sintered body prepared in Examples 7 to 12.

11 is a graph showing the change in shrinkage according to the sintering temperature of the non-pressurized sintered body prepared in Examples 13 to 18.

12 is a graph showing the change in shrinkage according to the sintering temperature of the oxide sintered body prepared in Comparative Examples 1 to 4.

13 is an XRD graph showing each crystal structure of the non-pressurized sintered body prepared in Example 9 and the pressed sintered body prepared in Comparative Examples 1 and 5.

14 is a graph showing sheet resistance characteristics of unit films prepared with compositions of Examples 1, 9, and Comparative Example 1;

15 is a graph of average reflectance results in the visible light region (wavelength 380 to 740 nm) of the double films prepared with the compositions of Examples 1, 9, and Comparative Example 1.

16 is an image of an etching evaluation result of a double film prepared with the compositions of Example 9 and Comparative Example 1.

Hereinafter, the present invention will be described in detail.

All terms (including technical and scientific terms) used in this specification may be used in a meaning that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

In addition, throughout the specification, when a certain component is said to "include", it means that it may further include other components, not excluding other components, unless otherwise stated. In addition, throughout the specification, "above" or "on" means not only the case of being located above or below the target part, but also the case of another part in the middle thereof, and must necessarily specify the direction of gravity It does not mean that it is located above the standard. Also, terms such as "first" and "second" in the present specification do not indicate any order or importance, but are used to distinguish components from each other.

MoO ₂ -Nb ₂ O ₅ material used as a conventional n-type semiconductor thin film is generally manufactured through a pressure sintering method. However, when the pressure sintering method is applied, it is not suitable in terms of mass productivity as the manufacturing process cost increases according to the equipment value. In addition, there was a limit to enlarging the size of the sintered body in the manufacturing process of applying high pressure.

In order to solve the above problems, it was difficult to apply the MoO ₂ -Nb ₂ O ₅ material to sintering without pressure because there is a limit to the increase in sintering density, and when the sintering temperature is increased, the amount of melting and volatilization increases, rather A decrease in density occurs. That is, heat is required as a driving force during sintering. In general, the higher the heat, the more advantageous it is in securing sinterability (densification), but in the case of some raw materials, problems such as volatilization occur, resulting in a lower density.

Therefore, the present invention is a molybdenum oxide-based sintered body that can simultaneously improve sinterability and secure high density by using a small amount of a specific dopant (M3) that assists sinterability in a difficult-to-sinter material having molybdenum oxide and niobium oxide as basic compositions. And it can provide a sputtering target using the same.

Specifically, the alkaline earth metal-based oxide dopant (M3) used in the present invention assists in securing the sintering driving force of MoO ₂ /MoO ₃ -Nb ₂ O ₅ , which is a sinter-resistant material, so that even if pressureless sintering is performed, the temperature drop effect is reduced. sintering density can be improved. For example, the molybdenum oxide sintered body of the present invention may have superior density and resistivity compared to a sintered body that does not contain a specific metal oxide (M3), and in particular, even if a pressureless sintered body is formed only by heat treatment without pressure, Density characteristics and resistivity characteristics equivalent to or higher than those of the oxide sintered body subjected to conventional pressure sintering (eg, HP, HIP, etc.) can be secured. In addition, compared to the pressure-sintered oxide sintered body, it is very excellent in terms of size and mass production of the sintered body, and has the advantage of low equipment cost.

In addition, since the particle size of the crystal grains constituting the oxide sintered body of the present invention is larger than the grain size of the molybdenum oxide sintered body pressure-sintered by simultaneously applying a predetermined pressure and heat treatment, it is more advantageous in terms of reaction. As an example, as can be seen in FIGS. 3 and 4, the pressurized sintered body is in the form of forcibly aggregating the initial raw materials by high pressure, so the size of the particles hardly increases, whereas the sintered body according to the present invention increases the size of the particles by the reaction It can be seen that has increased, and especially in the mutual reaction between different types of elements, it can be seen that it is advantageous in terms of reaction because the particles are combined in a complex form.

In addition, when there is no added element, the density of the molybdenum oxide target is very low and the specific resistance is high. In this way, when the resistance of the target is high, a problem in that plasma is not formed during DC sputtering is caused. In contrast, the molybdenum oxide target according to the present invention secures sinterability by adding a dopant, and can provide a high-density sintered target capable of sputtering even by non-pressure sintering.

<Oxide sintered body and sputtering target>

An example of the present invention is a metal oxide sintered body for producing a target for sputtering containing molybdenum oxide as a main component. This sintered body is distinguished from the conventional sintered body in that it contains a metal oxide (M3) containing at least one alkaline earth metal as an essential component.

For one specific example, the oxide sintered body MoO ₂ And MoO ₃ Molybdenum oxide containing at least one of (M1); niobium oxide (M2); and a metal oxide (M3) containing at least one kind of alkaline earth metal, and at least 70% by weight of molybdenum oxide (M1) based on the total weight of the sintered body.

When a thin film is formed using the metal oxide sintered body having the above composition as a target material, the formed thin film has low reflection characteristics and at the same time, heat resistance and chemical resistance are improved through optimization of the ratio and composition of molybdenum oxide. In addition, since the density is improved by adding a small amount of a specific dopant (M3), pressure sintering is not required, and a Mo-Nb-O-based sputtering target, which is a difficult-to-sinter material, can be manufactured.

Hereinafter, each component is explained in detail.

Molybdenum oxide contained in the oxide sintered body according to the present invention is a main component constituting the sintered body.

Molybdenum oxide (M1) is a component having a form in which oxygen is bonded to molybdenum, such as MoO ₂ , MoO ₃ , and MoO ₄ . In the present invention, as molybdenum oxide (M1), MoO _{2 ,} MoO ₃ , or MoO ₂ and Mixtures of MoO ₃ may be used. At this time, when using a mixture of MoO ₂ and MoO ₃ as molybdenum oxide, the mixing ratio between them is not particularly limited and can be properly adjusted within a conventional content range known in the art. Meanwhile, since MoO ₃ has a melting point of about 800°C, it volatilizes at a high temperature of 1000°C or higher. Accordingly, in the present invention, it is preferable to use MoO ₂ as the molybdenum oxide.

One of the additive components included in the oxide sintered body according to the present invention is niobium oxide (M2).

Niobium oxide (M2) is an oxide dopant that improves chemical resistance and heat resistance, and chemical resistance and heat resistance of molybdenum oxide can be improved by adding the metal oxide. The niobium oxide is not particularly limited as long as it has a form in which oxygen is bonded to niobium, and may be, for example, Nb ₂ O ₅ . In the following description, the niobium oxide component is symbolized and expressed as M2.

Another of the additive components included in the oxide sintered body according to the present invention is a metal oxide (M3) containing at least one kind of alkaline earth metal.

For example, the metal oxide M3 may include at least one of Ba, Ca, Mg, and Sr, and may specifically include the first metal oxide M3-1 including at least one of Ca and Mg. can

The first metal oxide (M3-1) serves as a dopant to show a density increasing effect by assisting the sinterability of the difficult-to-sinterable molybdenum oxide. Chemical resistance and heat resistance characteristics of molybdenum oxide may be improved by adding the first metal oxide. The first metal oxide (M3-1) is not particularly limited as long as it has a form in which oxygen is bonded to at least one element (A) of Ca and Mg, and is, for example, 1 selected from the group consisting of CaCO ₃ and MgO. May include more than one species.

For another example, the metal oxide (M3) may include a first metal oxide (M3-1); and a second metal oxide (M3-2) containing at least one metal selected from the group consisting of Co, Si, Y, and Ga.

The second metal oxide (M3-2) may serve to increase the sinterability of molybdenum oxide by assisting the above-described first metal oxide. The second metal oxide (M3-2) is not particularly limited as long as it has a form in which oxygen is bonded to at least one element of Co, Si, Y, and Ga. For example, Co ₃ O ₄ , SiO ₂ , Y ₂ It may include one or more selected from the group consisting of O ₃ , and Ga ₂ O ₃ . At this time, when the first metal oxide (M3-1) and the second metal oxide (M3-2) are mixed as the metal oxide (M3), the mixing ratio thereof is not particularly limited, and for example, the weight ratio is 1: 0.3 to 2.5. , More specifically, it may be 1: 0.5 to 2.0 weight ratio.

The metal oxide sintered body including the above-described molybdenum oxide (M1), niobium oxide (M2), and (semi)metal oxide (M3) contains molybdenum oxide (M1) and niobium oxide (M2) based on 100% by weight of the sintered body. 90% by weight or more and less than 100% by weight, and (semi)metal oxide (M3) may be included in more than 0% by weight and less than 10% by weight. More specifically, 95.0 to 99.5% by weight of molybdenum oxide (M1) and niobium oxide (M2); and 0.5 to 5.0 wt% of (semi)metal oxide (M3). Here, the content ratio of molybdenum oxide (M1) and niobium oxide (M2) is 50:50 to 90:10 weight ratio, specifically 70:30 to 90:10 weight ratio, more specifically 75:25 to 90:10 weight ratio can be configured. In the present invention, when the ratio of molybdenum oxide occupies 70% by weight or more in the entire metal oxide sintered body, it may have low reflection characteristics when deposited as a thin film.

The oxide sintered body according to the present invention configured as described above has a relative density of 80% or more, even when pressure-free sintering is performed, and specifically may be 90% or more. In this case, the upper limit is not particularly limited. In addition, the specific resistance of the oxide sintered body is 1×10 ^-2 Ωcm or less, and the lower limit thereof is not particularly limited.

And the size (D50) of crystal grains included in the oxide sintered body is not particularly limited, and may be, for example, 1 to 30 μm. Specifically, the crystal grain size of the sintered body prepared under pressurized conditions may be 1 to 3 μm, and the crystal grain size of the sintered body prepared under non-pressurized conditions may be 3 to 30 μm. Particularly, the particle size of the crystal grains constituting the oxide sintered body of the present invention is larger than the particles of the molybdenum oxide sintered body artificially pressurized by pressing the powder by HP or HIP. Accordingly, there is an advantage that it is more advantageous in terms of reaction.

For one specific example, the average grain diameter (D ₅₀ ) constituting the non-pressurized sintered body of the present invention may satisfy the condition of Equation 1 below.

[Equation 1]

G _N / G _P ≥ 3.0

In the above formula,

G _N is the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to non-pressure heat treatment at 1,400±200 ° C. for 2 hours,

G _P is the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to pressure heat treatment for 2 hours under conditions of 30 MPa and 830° C.

Specifically, the average grain diameter (D ₅₀ ) constituting the unpressurized sintered body according to Equation 1 may be 5.0 or more, more specifically 10.0 or more. For example, the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to non-pressure heat treatment may be 3 to 30 μm, and the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to pressure heat treatment may be 1 μm to 3 μm.

In addition, the sputtering target according to another embodiment of the present invention, an oxide sintered body containing the above-described molybdenum oxide as a main component; and a backing plate bonded to one surface of the sintered body to support the sintered body.

Here, the backing plate is a substrate for supporting the sintered body for the sputtering target, and a conventional backing plate known in the art may be used without limitation. At this time, the material constituting the backing plate and its shape are not particularly limited.

<Method for producing oxide sintered body and sputtering target>

Hereinafter, a method for manufacturing an oxide sintered body and a sputtering target according to an embodiment of the present invention will be described. However, it is not limited only by the following manufacturing method, and each process step may be modified or selectively used in combination as needed.

For one embodiment of the manufacturing method, (i) molybdenum oxide (M1); niobium oxide (M2); preparing a raw material powder comprising; a metal oxide (M3) containing at least one kind of alkaline earth metal (A); (ii) preparing a molded body using the raw material powder ('step S20'); (iii) preparing a sintered body by sintering the molded body at 1,200 to 1,600 ° C. for 1 to 20 hours without pressure ('S30 step'); may be configured to include.

Hereinafter, the manufacturing method will be described by dividing each process step.

(i) Raw material powder preparation ('S10 step')

In step S10, raw material powder including molybdenum oxide (M1), niobium oxide (M2), and (semi)metal oxide (M3) containing at least one kind of alkaline earth metal (A) is prepared. Specifically, at least one type of first metal oxide (M3-1) powder selected from the group consisting of molybdenum oxide (M1), niobium oxide (M2), CaCO ₃ and MgO, if necessary, second metal oxide (M3-2) After weighing the powder according to the target composition, each powder is put into a mixer and pulverized and mixed to prepare a mixture.

When mixing the above-described raw material powders, conventional additives known in the art, such as a binder, a dispersing agent, and an antifoaming agent, may be further included as needed. At this time, the amount of the additive can be properly adjusted within a conventional range known in the art, and for example, 0.01 to 10% by weight relative to the total weight of the powder in the slurry (eg, 100% by weight) may be used.

Mixing and grinding of the raw material powder is not particularly limited, and may be performed using a conventional ball mill, attrition mill, bead mill, or the like known in the art. For example, the mixed raw material powder may be subjected to a dry ball mill process using zirconia balls. Here, the zirconia balls can be weighed 1 to 3 times the amount of powder, and the ball mill can be performed at a speed of 100 to 300 rpm for 10 to 36 hours.

As a specific example of the step S10, in order to mix and pulverize the raw material powder through a wet ball mill, pre-measured elemental powder is introduced using a prepared PE cylinder, and about 2 to 4 times the amount of the raw material, preferably A zirconia ball of 3 times the weight is added. After that, distilled water or pure water is added at a level of about 1.5 times the raw material to proceed with the ball mill.

Thereafter, the wet pulverized mixture is dried in a dry oven, and ball milling is performed again to obtain a dried raw material powder. At this time, the drying conditions are not particularly limited, and for example, drying may be performed at about 90 to 110 ° C. for about 10 to 15 hours in a dry oven.

Subsequently, the dried mixture is subjected to a ball mill again to obtain dry raw material powder. If necessary, the zirconia balls and powder are separated by filtering through a mesh of about 90 to 110 mesh, specifically, 100 mesh.

(ii) Manufacture of molded body ('S20 step')

In the S0 step, a molded body is manufactured from the prepared raw material powder, and more specifically, a molded body having a predetermined standard is manufactured through a process of putting the raw material powder into a molding machine and molding it.

In order to increase the density of the molded body, the molding process may be carried out twice. For example, the primary molding process may use a uniaxial molding machine, and the secondary molding process may use an isostatic pressure molding machine.

Conditions in the primary molding and secondary molding processes are not particularly limited and may be appropriately adjusted within common conditions known in the art. For example, the pressure at the time of primary molding after inputting the raw material powder into the uniaxial molding machine is not particularly limited, and may specifically be 10 MPa or more per unit area. In addition, the pressure at the time of secondary molding after the primary molded body is put into the isostatic pressure molding machine is not particularly limited, and may be, for example, 200 MPa or more per unit area, and preferably 200 to 300 MPa.

For a specific example of the step S20, a primary molded body is manufactured using a 20Φ standard STS mold according to the weight of the determined powder. At this time, the pressure may proceed under the minimum pressure condition constituting the shape, for example, about 10 MPa, and the time may proceed at a level of holding for 1 minute. After that, the secondary molding was carried out for several hours under the condition of 200 MPa using hydrostatic pressure molding (CIP). At this time, since the second hydrostatic pressure proceeds with an organic solvent including water, it can proceed in a state in which it is put into an acrylic-based sealing material (eg, a bag).

(iii) Manufacturing a sintered body ('Step S30')

In step S30, a sintered body is prepared by sintering the manufactured molded body under predetermined conditions.

At this time, the sintering conditions are not particularly limited and may be appropriately adjusted within common conditions known in the art. For example, it may be pressure-free sintering at 1,200 to 1,600 ° C. for 1 to 20 hours, and specifically for 1 to 4 hours. The sintering may be performed under an oxygen atmosphere or under inert conditions.

For a specific example of the step S30, the prepared molded body is put into an alumina crucible of a certain standard and sintering is performed. In this experiment, in order to confirm the difference in characteristics between the molded body before heat treatment and the unpressurized sintered body after heat treatment, the weight, diameter, height, etc. of the molded body and the sintered body were measured and each physical property was compared (see Table 2 and FIGS. 9 to 12 below).

The pressure-free sintered body manufactured through this process may have a relative density of 80% or more, specifically 90% or more. In this case, the upper limit is not particularly limited.

(iv) Sputtering target manufacturing

Next, the sintered compact is taken out and processed. For example, in order to polish the surface of the target after taking out the sintered body, each upper and lower portion of the target may be processed by 1 mm or more.

After that, a productized sputtering target is manufactured through diffusion bonding and final processing commonly known in the art.

Specifically, the sintered body obtained in step S30 is bonded to a backing plate. At this time, indium can be used as an adhesive, and it is preferable to have a bonding rate of 95% or more. Subsequently, a final sputtering target may be obtained by processing to a final target thickness using processing equipment and performing bead and/or arc spray treatment on the surface of the backing plate.

A metal oxide target may be manufactured through the above process. The target density of the prepared target is 90% or more, and specifically, it is preferable to be 95% or more.

<Oxide thin film>

Another example of the present invention is a metal oxide thin film deposited using the molybdenum oxide-based target described above. Such a metal oxide thin film may be formed by performing sputtering using the above-described sintered body as a target material.

Although slight differences in components may occur depending on the deposition atmosphere, the oxide thin film is manufactured by sputtering the above-described oxide target, and thus has substantially the same composition as the target. Accordingly, an oxide thin film having a relative density of 90% or more and excellent resistivity of 1×10 ^-2 Ωcm or less can be formed. In addition, specific metal oxides and metals are added in a predetermined range to molybdenum oxide, which is the main raw material, but chemical resistance and heat resistance characteristics can be improved through optimization of the molybdenum oxide ratio and composition.

The metal oxide thin film according to the present invention may be formed (deposited) using a conventional sputtering method known in the art. For one embodiment of the manufacturing method, after mounting the above-mentioned molybdenum oxide pressure-free sintered sputtering target, it includes depositing at room temperature under an oxygen and / or argon atmosphere in a vacuum chamber. At this time, sputtering may be performed using DC sputter.

As the substrate and sputtering device used, conventional ones known in the art may be used without limitation. Specifically, it can be formed while supplying oxygen or oxygen and high-purity argon gas into a vacuum chamber at a rate of 80 to 110 sccm (standard cubic centimeters per minute), and specifically supplied at a rate of 95 to 105 sccm, forming a film It can be deposited at room temperature (RT) without applying temperature to the substrate. In addition, the power density of the DC sputter may be 1.0 to 2.0 W/cm ² , and the thickness of the metal oxide thin film may be 300 to 500 Å, but is not particularly limited thereto.

The oxide thin film obtained as described above can be used in various ways in the manufacture of semiconductor devices, and for example, it can be applied for forming wires or electrodes in the manufacture of semiconductors. In particular, the metal oxide thin film may be used as at least one of a gate layer, a source layer, and a drain layer of a thin film transistor (TFT). As described above, when the thin film of the present invention is used in the barrier layer of the source and drain electrodes included in the thin film transistor, the contact resistance can be reduced, and the thin film transistor has excellent transparency and a low refractive index, so that the physical properties of the thin film transistor can be improved.

Since the molybdenum oxide-based sputtering target and the oxide thin film formed therefrom according to the present invention described above have high density and excellent resistivity characteristics even under no pressure, they are connected to TFT structures of LCDs and OLEDs or electron injection layers of organic electroluminescent devices. resistance can be kept low. Accordingly, the oxide thin film described above may be used in various display devices such as liquid crystal display devices or organic light emitting display devices, information transmission devices such as flat panel displays such as LCD, PDP, OLED, and LED; surface light source lighting devices such as OLED and LED touch panels; It can also be applied without limitation to mobile phones, tablets and/or information delivery devices using the same.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are only to illustrate the present invention, and the present invention is not limited by the following examples.

[Examples 1 - 17: Preparation of MoO ₂ -Nb ₂ O ₅ -α sintered body]

After mixing molybdenum oxide (M1), niobium oxide (M2), and (semi)metal oxide (M3) in the composition ratio shown in Table 1 below, a molded body was manufactured.

When manufacturing the molded body, most samples were made with 20Φ discs, but some compositions were also made with 50Φ. Thereafter, the oxide sintered body of Examples 1 to 17 was produced by heat treatment without pressure at about 1,200 to 1,600 ° C. for 2 hours using a heat treatment facility.

division		entire wt %	MoO 2 (M1)	Nb 2 O 5 (M2)	Metal oxide (M3)
					M3-1		M3-2
					CaCO 3	MgO	GeO 2	CuO	TiO 2	Co 3 O 4	SiO 2	Y 2 O 3	Ga 2 O 3
α composition single adding	Comparative Example 1	100	75.0	25.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Comparative Example 2	100	73.5	24.5	0.0	0.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0
	Comparative Example 3	100	73.5	24.5	0.0	0.0	0.0	2.0	0.0	0.0	0.0	0.0	0.0
	Comparative Example 4	100	73.5	24.5	0.0	0.0	0.0	0.0	2.0	0.0	0.0	0.0	0.0
	Comparative Example 5	100	75.0	25.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 1	100	74.3	24.8	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 2	100	73.5	24.5	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 3	100	71.3	23.8	5.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 4	100	74.3	24.8	0.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 5	100	73.5	24.5	0.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 6	100	71.3	23.8	0.0	5.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
α composition complex adding	Example 7	100	74.3	24.8	0.5	0.5	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 8	100	73.5	24.5	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 9	100	72.8	24.3	1.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 10	100	72.0	24.0	1.0	3.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 11	100	72.8	24.3	2.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 12	100	71.3	23.8	2.5	2.5	0.0	0.0	0.0	0.0	0.0	0.0	0.0
	Example 13	100	72.8	24.3	0.0	2.0	0.0	0.0	0.0	1.0	0.0	0.0	0.0
	Example 14	100	72.8	24.3	1.0	0.0	0.0	0.0	0.0	2.0	0.0	0.0	0.0
	Example 15	100	72.8	24.3	1.0	0.0	0.0	0.0	0.0	0.0	2.0	0.0	0.0
	Example 16	100	72.8	24.3	1.0	0.0	0.0	0.0	0.0	0.0	0.0	2.0	0.0
	Example 17	100	72.8	24.3	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	2.0

[Comparative Examples 1-4: Preparation of MoO ₂ -Nb ₂ O ₅ and α-added sintered body]

Except for changing the composition of the input oxide as shown in Table 1, a molded body was manufactured in the same manner as in the above embodiment. Thereafter, heat treatment was performed at about 1200 to 1600 ° C. for 2 hours using a heat treatment facility to produce sintered bodies of Comparative Examples 1 to 4, respectively.

[Comparative Example 5: Preparation of sintered body]

Molybdenum oxide (M1) and niobium oxide (M2) were weighed in the ratio of the composition shown in Table 1 above. The weighed powder was put into a 1L plastic container, and alumina balls were added in an amount three times the amount of the powder. The alumina ball used was a 3-10 mm ball. Upon completion of the input of the measured powder and balls, dry mixing was performed for 8 hours at a speed of 170 to 230 rpm in a ball mill machine. The obtained dry powder was pressurized and sintered by a hot press. At this time, the internal vacuum condition of the hot press was performed at 30 Mpa, the heating rate was 3 to 7 ° C, the maximum temperature was 830 ° C, and the holding time was maintained for about 2 hours to perform sintering and then furnace cooling. The sintered body of Comparative Example 5 was prepared through the process as described above.

[Experimental Example 1: Evaluation of Tissue Change by Heat Treatment of Molded Body]

The structure change of the sintered body according to heat treatment was evaluated using the molded body to which metal oxide was added and not added.

1 is a photograph showing the structure change of a sintered body according to the heat treatment temperature using the molded body of Example 9 to which metal oxide (M3) is added, and FIG. 2 is a molded body of Comparative Example 1 to which metal oxide (M3) is not added. This is a photograph showing the change in the structure of the sintered body according to the heat treatment temperature.

As a result of the experiment, it was confirmed that the molded body to which the metal oxide was added had a relatively large change in structure, such as suppression of pores of the sintered body according to the heat treatment temperature, compared to the molded body to which no metal oxide was added (see FIGS. 1 and 2 below).

[Experimental Example 2: Average Particle Diameter Evaluation of Sintered Body]

Using the sintered bodies heat-treated under pressurized and non-pressurized process conditions, their structure change and average particle diameter were evaluated, respectively.

Specifically, as samples, the sintered body of Example 9 prepared under no pressure and Comparative Example 5 prepared under pressure were used. These two types of samples were cut in a size of 10X10X10mm using a metal blade, polished for several minutes using a polishing machine from SiC paper #100 to #2000, and finally prepared using a 1 μm paste slurry and a microfiber cloth. Thereafter, the sample was immersed at about 200 ° C. for 1 minute using hydrogen peroxide solution so that the surface of the tissue was exposed and heat treated.

In addition, the measurement of the average particle diameter of the sintered body was observed at the same magnification of 1,000 for each sample using FE-SEM (Hitachi, S-4800), and 5 lines were drawn randomly on the measured picture, and the following math for about 100 particles It was calculated using the linear intercept method according to Equation 2.

[Equation 2]

D = 1.56 × C/MN

In the above formula, D = average particle diameter, C = total length of the line, M = magnification, and N = number of particles on the line.

3 and 4 are SEM photographs showing fractured and polished surfaces of the powder structure of the mixed raw materials, the structure of the non-pressurized sintered body prepared in Example 9, and the structure of the pressed sintered body prepared in Comparative Example 5, respectively.

As can be seen in FIGS. 3 and 4, since the pressurized sintered body of Comparative Example 5 is in the form of forcibly aggregating the initial raw materials by high pressure, it can be seen that the size of the particles hardly increases. In contrast, it can be seen that the grain size of the sintered body of Example 9 is increased by the reaction, and it can be seen that it is advantageous in terms of reaction, especially since the particles are combined in the mutual reaction between different types of elements. there is.

[Experimental Example 3: Evaluation of physical properties of molded article]

The physical properties of each molded article prepared in Examples 1 to 17 and Comparative Examples 1 to 4 were evaluated as follows.

Specifically, the diameter (D) and height (T) of each molded body were measured using a vernier caliper, and the weight (Mass) was weighed using a scale. In addition, the relative density was converted into a percentage of the theoretical density by converting the input amount of each weight into volume%, and the results are shown in Table 2 below. The density of the measured sample was calculated by weight/volume, and was expressed as an average value when several identical samples were produced.

For reference, in Table 2 below, each sample had a low relative density because sintering was not applied, and the relative density of each sintered body after sintering (heat treatment) was approximately 96%.

division		Additive (M3)	D (mm)	T (mm)	Mass (g)	relative density (%)
α composition exclusive addition	Comparative Example 1	-	19.56	6.63	6.97	59.6
	Comparative Example 2	GeO2	19.60	6.13	7.16	66.5
	Comparative Example 3	CuO	19.60	5.87	6.99	67.1
	Comparative Example 4	TiO2	19.79	5.98	7.03	65.6
	Comparative Example 5	-	-	-	-	-
	Example 1	CaCO3	19.89	5.78	7.16	68.4
	Example 2	CaCO3	19.75	6.11	7.04	65.5
	Example 3	CaCO3	19.83	6.10	7.15	66.7
	Example 4	MgO	19.85	5.77	7.14	68.6
	Example 5	MgO	19.78	6.07	7.09	65.6
	Example 6	MgO	19.87	5.98	7.08	67.1
α composition complex addition	Example 7	CaCO3, MgO	19.93	5.71	7.11	68.5
	Example 8	CaCO3, MgO	48.12	8.46	60.26	67.4
	Example 9	CaCO3, MgO	47.89	8.61	60.17	67.2
	Example 10	CaCO3, MgO	19.91	5.89	7.18	68.3
	Example 11	CaCO3, MgO	19.91	6.01	7.29	67.7
	Example 12	CaCO3, MgO	47.69	9.01	60.37	65.6
	Example 13	MgO, Co3O4	19.90	5.84	7.17	68.1
	Example 14	CaCO3, Co3O4	19.89	5.91	7.30	68.0
	Example 15	CaCO3, SiO2	19.81	5.91	7.12	68.5
	Example 16	CaCO3, Y2O3	19.79	5.86	7.08	67.4
	Example 17	CaCO3, Ga2O3	19.88	5.85	7.15	67.4

[Experimental Example 4: Evaluation of Density and Shrinkage Rate of Sintered Body]

After heat treatment was performed on each sample prepared in Examples 1 to 17 and Comparative Examples 1 to 4, the change in physical properties of each sintered body was measured.

(1) Density evaluation after heat treatment

The density evaluation of the sintered body after heat treatment was measured in the same manner as in Experimental Example 3 described above. As an example, the results of the relative density calculated by measuring the diameter, height and weight of the heat-treated sintered body are shown in FIGS. 5 to 8, respectively.

As a result of the experiment, in Examples 1 to 17, it was found that the relative density also increased significantly as the sintering temperature was raised from 1200 ° C to 1600 ° C (see FIGS. 5 to 7). In contrast, in the case of Comparative Examples 1 to 4, it was found that the relative density of the molded body was lower than or similar to this depending on the sintering temperature. In addition, the slope according to the temperature rise was low, and in the case of Comparative Example 1, it was found that the relative density did not increase any more even if the temperature was further increased (see FIG. 8). In addition, in the case of Comparative Example 5, the sintered density was only about 95 to 97%.

(2) Evaluation of shrinkage before and after heat treatment

The shrinkage rate was calculated by measuring the diameter and height of the molded body before heat treatment and the sintered body after heat treatment, respectively. The calculated shrinkage results are shown in Figures 9 to 12, respectively.

As a result of the experiment, in the case of Comparative Examples 1 to 4, the shrinkage rate change due to heat treatment was not large (see FIG. 12). In contrast, in the case of Examples 1 to 17, it was found that the change rate of the shrinkage rate of the sintered body according to the heat treatment was relatively high (see FIGS. 9 to 11).

[Experimental Example 5: Evaluation of Resistivity of Sintered Body]

Resistivity characteristics were evaluated for each sintered body sample prepared in Examples 1 to 17 and Comparative Examples 1 to 5.

Specifically, as a sample of the sintered body, a sample of 1500 ° C, which is an intermediate temperature range, was used. After measuring the specific resistance of the sample using Loresta-GX MCP-T700 product (Mitsubishi chemical Co.), the results are shown in Table 3 below.

division		additive (M3)	content (wt%)	Resistivity (10^-3 Ω㎝)
				award	under	average
α composition exclusive addition	Comparative Example 1	-	0.0	9.256	8.264	8.760
	Comparative Example 2	GeO2	2.0	8.526	7.863	8.195
	Comparative Example 3	CuO	2.0	8.547	7.861	8.204
	Comparative Example 4	TiO2	2.0	6.258	6.754	6.506
	Comparative Example 5	-	0.0	2.189	1.985	2.087
	Example 1	CaCO3	1.0	5.213	5.023	5.118
	Example 2	CaCO3	2.0	4.787	4.968	4.878
	Example 3	CaCO3	5.0	3.698	3.562	3.630
	Example 4	MgO	1.0	3.245	3.021	3.133
	Example 5	MgO	2.0	1.995	2.204	2.100
	Example 6	MgO	5.0	2.904	3.230	3.067
α composition complex addition	Example 7	CaCO3 : MgO	0.5 : 0.5	5.223	5.129	5.176
	Example 8	CaCO3 : MgO	1.0 : 1.0	4.438	4.290	4.364
	Example 9	CaCO3 : MgO	1.0 : 2.0	2.199	2.209	2.204
	Example 10	CaCO3 : MgO	1.0 : 3.0	1.595	1.343	1.469
	Example 11	CaCO3 : MgO	2.0 : 1.0	2.535	2.445	2.490
	Example 12	CaCO3 : MgO	2.5:2.5	1.890	1.990	1.940
	Example 13	Co3O4 : MgO	1.0 : 2.0	2.484	2.094	2.289
	Example 14	Co3O4: CaCO3	2.0 : 1.0	3.393	2.048	2.721
	Example 15	CaCO3 : SiO2	1.0 : 2.0	5.356	5.125	5.241
	Example 16	CaCO3: Y2O3	1.0 : 2.0	5.126	5.857	5.492
	Example 17	CaCO3 : Ga2O3	1.0 : 2.0	4.226	4.671	4.449

As shown in Table 3, it can be confirmed that the sintered bodies of Examples 1 to 17 including a predetermined metal oxide as an additive have excellent resistivity characteristics compared to the sintered bodies of Comparative Examples 1 to 5 without the above additive. there was.

[Experimental Example 6: Analyzing and evaluating the crystal structure of the sintered body]

Crystal structure characteristics of each sintered sample prepared in Example 9 and Comparative Examples 1 and 5 were evaluated.

Specifically, Example 9 and Comparative Example 1 were measured by cutting samples sintered at 1500 ° C, which is an intermediate temperature range, into 10 X 10 X 3 mm (T). In Comparative Example 5, samples sintered at 830° C. were cut into the same size and measured. The X-ray diffraction equipment used in the measurement was a Pro MRD product (Malvern panalytical company), and the 2 theta range was measured at 20 to 60 degrees.

As shown in FIG. 13, it was found that the crystal structure of the sintered body of Comparative Example 5 prepared by pressure sintering was rather similar to that of the initial mixed powder, unlike the sintered bodies of Comparative Example 1 and Example 9.

[Experimental Example 7: Evaluation of Sheet Resistance and Reflectance Characteristics of Thin Film]

The properties of thin films prepared from each sintered body of Example 1, Example 9 and Comparative Example 1 were evaluated as follows.

Specifically, a unit film was formed by depositing a 4-inch target prepared with the composition of Examples and Comparative Examples at 300 to 500 Å through a DC sputter. In addition, a 4-inch Cu target was deposited on the unit film at 4000 to 6000 Å through a DC sputter to prepare a double film. The sheet resistance and reflectance characteristics of the prepared thin film are shown in FIGS. 14 and 15, respectively.

14 is a graph showing sheet resistance characteristics of unit films prepared with compositions of Examples 1, 9, and Comparative Example 1; In the case of the thin films of Examples 1 and 9, it was found that they had significantly lower sheet resistance characteristics compared to Comparative Example 1.

15 is a graph of average reflectance measurements in the visible light region (wavelength of 380 to 740 nm) using the double films prepared with the compositions of Examples 1, 9, and Comparative Example 1. Compared to the double film of Comparative Example 1 having an average reflectance exceeding approximately 10%, the double films of Examples 1 and 9 had average reflectance characteristics of 9% or less, indicating that better reflectance characteristics were secured. there was.

[Experimental Example 8: Evaluation of Chemical Stability of Thin Film]

A photoresist (PR) process was performed on the double films prepared with the compositions of Example 9 and Comparative Example 1. During the PR process, a sample for etching evaluation was prepared by exposure to light to form a line width of 50 to 100 nm. The results are shown in Table 4 and FIG. 16 below.

	Degree of damage to molybdenum oxide thin film (nm)	Angle after etching (°)
Comparative Example 1	1.75	51.5
Example 9	0	48.6

16 is an image of an etching evaluation result of a double film prepared with the composition of Example 9 and Comparative Example 1, FIG. 16(a) is an image of Example 9, and 16(b) is an image of Comparative Example 1.

As shown in Table 4 and FIG. 16 (a), the thin film of Example 9 exhibited a significantly lower degree of thin film damage and a lower angle after the etching process compared to Comparative Example 1. Accordingly, it was confirmed that the oxide sintered body according to the present invention had excellent chemical stability.

Claims (15)

1. Molybdenum oxide (M1) containing at least one of MoO ₂ and MoO ₃ ;

   niobium oxide (M2); and

   A metal oxide (M3) containing at least one kind of alkaline earth metal;

   An oxide sintered body containing at least 70% by weight or more of molybdenum oxide (M1) based on the total weight of the sintered body.
2. According to claim 1,

   The metal oxide (M3) is,

   An oxide sintered body comprising a first metal oxide (M3-1) containing at least one of Ca and Mg.
3. According to claim 2,

   Wherein the first metal oxide (M3-1) includes at least one selected from the group consisting of CaCO ₃ , and MgO.
4. According to claim 2,

   The metal oxide (M3) is,

   a first metal oxide (M3-1); and

   A second metal oxide (M3-2) containing at least one metal selected from the group consisting of Co, Si, Y, and Ga; containing an oxide sintered body.
5. According to claim 4,

   The second metal oxide (M3-2) includes at least one selected from the group consisting of Co ₃ O ₄ , SiO ₂ , Y ₂ O ₃ , and Ga ₂ O ₃ , oxide sintered body.
6. According to claim 1,

   The metal oxide (M3) is included in an amount greater than 0% by weight and less than or equal to 10.0% by weight based on 100% by weight of the sintered body.
7. According to claim 1,

   The molybdenum oxide (M1) and the niobium oxide (M2) are included in 90.0% by weight or more and less than 100% by weight based on 100% by weight of the oxide sintered body,

   The content ratio of the molybdenum oxide (M1) and the niobium oxide (M2) is 50: 50 to 90: 10 weight ratio, the oxide sintered body.
8. According to claim 1,

   The oxide sintered body,

   molybdenum oxide (M1); niobium oxide (M2); And a metal oxide (M3) that is mixed and molded and then non-pressure sintered, an oxide sintered body.
9. According to claim 8,

   The average grain diameter (D ₅₀ ) constituting the pressure-free sintered oxide sintered body satisfies the condition of Equation 1 below:

   [Equation 1]

   G _N / G _P ≥ 3.0

   In the above formula,

   G _N is the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to non-pressure heat treatment at 1,400±200 ° C. for 2 hours,

   G _P is the average grain diameter (D ₅₀ ) of the oxide sintered body subjected to pressure heat treatment at 30 MPa and 830° C. for 2 hours.
10. According to claim 1,

    The resistivity is less than 1×10 ^-2 Ωcm,

    An oxide sintered body having a relative density of 80% or more.
11. A sputtering target comprising the oxide sintered body according to any one of claims 1 to 10.
12. An oxide thin film formed from the sputtering target of claim 11.
13. A thin film transistor in which the thin film of claim 12 is used as one of a gate layer, a source layer, and a drain layer.
14. A display device comprising the oxide thin film of claim 12 .
15. (i) molybdenum oxide (M1); niobium oxide (M2); preparing a raw material powder containing; a metal oxide (M3) containing at least one kind of alkaline earth metal;

    (ii) preparing a molded body using the raw material powder; and

    (iii) preparing a sintered body by heat-treating the molded body at 1,200 to 1,600° C. for 1 to 20 hours without pressure;

    A method for producing an oxide sintered body of claim 1 comprising a.

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