Molybdenum oxide-based sintered compact, thin film using sintered compact, thin film transistor comprising thin film, and display device

Abstract

The present invention provides: a molybdenum oxide-based sintered compact having excellent low reflection, low resistance, and heat resistance properties; a thin film using the sintered compact; a thin film transistor comprising the thin film; and a display device.

Description

Molybdenum oxide-based sintered body, thin film using the sintered body, thin film transistor and display device including the thin film

[0001] The present invention relates to a molybdenum oxide-based sintered body having excellent low reflection, low resistance, and heat resistance, a thin film using the sintered body, a thin film transistor including the thin film, and a display device.

[0002]

[0003] Low-reflectivity conductive thin films are commonly used in flat panel displays (FPDs), touch screen panels, solar cells, light emitting diodes (LEDs), and organic light emitting diodes (OLEDs).

[0004] Indium oxide-tin oxide (In2O3-SnO2) ("ITO") is a representative material for this purpose, and ITO compositions are used to form conductive thin films with high visible light transmittance and electrical conductivity. While these ITO compositions exhibit excellent low-reflectivity performance, they are not cost-effective, and research into materials that can completely or partially replace indium oxide is ongoing.

[0005] However, the area of ​​interest in these studies is the low reflectivity of the thin film formed through the target material, and it is necessary to consider the chemical resistance and heat resistance characteristics that can increase the reliability of the thin film for long-term use.

[0006] [Prior Art Literature]

[0007] [Patent Document]

[0008] (Patent Document 1) Republic of Korea Publication No. 10-2008-0058390

[0009]

[0010] Meanwhile, the inventors of the present invention have noticed that existing molybdenum oxide targets using molybdenum oxide (M1) in an excess of 60 wt% or more mainly exhibit only low-reflection characteristics, while heat resistance and low-resistance characteristics are relatively poor.

[0011] Accordingly, the present invention has as its technical object the provision of a sintered body for a sputtering target having excellent low-reflection characteristics, low-resistance characteristics, and heat resistance simultaneously by controlling the content of molybdenum oxide, which is the main raw material, to a low level and at the same time controlling at least two specific metal oxides (M2, M3) and a metal (M4) to a predetermined content range, a metal oxide thin film formed therefrom, and a thin film transistor and a display device formed with the metal oxide thin film.

[0012] Other objects and advantages of the present invention can be more clearly explained by the detailed description of the invention and the claims below.

[0013]

[0014] In order to achieve the above technical problem, the present invention provides an oxide sintered body including molybdenum oxide (M1); a first metal oxide (M2) including at least one first element selected from the group consisting of Nb, Ta, Zr, Ti, Sn, and W; a second metal oxide (M3) including at least one second element selected from the group consisting of Y, Hf, Ge, V, Al, Si, Mn, and Co; and at least one metal (M4) selected from the group consisting of Mo, Ti, Cr, W, and Cu, and containing less than 50 wt% of the molybdenum oxide (M1) based on the total weight of the sintered body.

[0015] In one embodiment of the present invention, the molybdenum oxide (M1) may include at least one of MoO2 and MoO3.

[0016] In one embodiment of the present invention, the oxide sintered body is Mo4O 11 , Mo 17 O 47, Mo5O 14 , Mo8O 23 , Mo9O 26 , and Mo 18 O 52 It may be substantially free of at least one substoichiometric molybdenum oxide selected from the group consisting of:

[0017] In one embodiment of the present invention, the molybdenum oxide (M1) may be included in an amount of 40 wt% or more and less than 50 wt% based on 100 wt% of the oxide sintered body.

[0018] In one embodiment of the present invention, the first metal oxide (M2) may be included in an amount of 20 to 25 wt% based on 100 wt% of the oxide sintered body.

[0019] In one embodiment of the present invention, the second metal oxide (M3) may be included in an amount of 1 to 10 wt% based on 100 wt% of the oxide sintered body.

[0020] In one embodiment of the present invention, the metal (M4) may be included in an amount of 20 to 40 wt% based on 100 wt% of the oxide sintered body.

[0021] In one embodiment of the present invention, the oxide sintered body may have (i) a weight % ratio of (M1+M2) / (M2) of 1.4 to 1.7%, and (ii) a weight % ratio of (M1+M2+M3+M4) / (M1+M2) of 1.2 to 1.6%.

[0022] In one embodiment of the present invention, the oxide sintered body has a resistivity of 1×10 -2 Ωcm or less, and the relative density may be 95% or more.

[0023] The present invention also provides a sputtering target including the above-described oxide sintered body.

[0024] The present invention also provides an oxide thin film formed from the aforementioned sputtering target.

[0025] In one embodiment of the present invention, the light reflectance (R1) for a wavelength of 550 nm before heat treatment may be 11.0% or less, and the light reflectance (R2) for a wavelength of 550 nm after heat treatment at a temperature of 350°C for 30 minutes or more may be 11.0% or less.

[0026] In one embodiment of the present invention, the difference (R2-R1) between the light reflectance (R2) after heat treatment at a temperature of 350°C and for 30 minutes or more and the light reflectance (R1) before heat treatment may be 1.0% or less.

[0027] In one embodiment of the present invention, the oxide thin film may be included as any one of a gate layer, a source layer, and a drain layer.

[0028] In addition, the present invention provides a display device including the above-described oxide thin film.

[0029]

[0030] According to an embodiment of the present invention, by reducing the content of molybdenum oxide (M1) that is conventionally used in excess of 60 wt% or more and optimizing the composition by adjusting two types of metal oxide dopants (M2, M3) and a metal dopant (M4) to a predetermined content, the sinterability of a molybdenum oxide-based sintered body is improved and high density is secured, thereby simultaneously having low reflection characteristics, low resistance characteristics, and excellent heat resistance.

[0031] Accordingly, the molybdenum oxide-based sintered body and sputtering target according to the present invention can be usefully applied to the formation of electrodes or wiring used in the TFT structure of LCDs and OLEDs, and the operational reliability of a thin film transistor or display device including an oxide thin film formed from the oxide sintered body can be secured.

[0032] Other effects of the present invention will be clearly understood and appreciated by experts or researchers in this technical field through the specific contents described below or during the process of implementing the present invention.

[0033]

[0034] Figure 1 is a graph showing the reflectivity evaluation of a molybdenum oxide thin film according to Example 1.

[0035] Figure 2 is a graph showing the change in reflectance of the molybdenum oxide thin film of Example 1 before and after heat treatment.

[0036]

[0037] Hereinafter, the present invention will be described in detail.

[0038] All terms (including technical and scientific terms) used in this specification may be used with meanings commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries should not be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0039] Furthermore, throughout the specification, when a part is said to "include" a component, unless otherwise specifically stated, this does not exclude other components but rather means that other components may be included. Furthermore, throughout the specification, the terms "above" or "on" include not only cases where the target part is located above or below it, but also cases where there is another part in between, and do not necessarily mean that the target part is located above it in the direction of gravity. In addition, terms such as "first" and "second" in the specification do not indicate any arbitrary order or importance, but are used to distinguish between components.

[0040] Sintered body and sputtering target

[0041] An example of the present invention is a metal oxide sintered body for manufacturing a sputtering target having molybdenum oxide as a main component.

[0042] For example, the sintered body includes (i) molybdenum oxide (M1); (ii) a first metal oxide (M2) including at least one first element selected from the group consisting of Nb, Ta, Zr, Ti, Sn, and W; (iii) a second metal oxide (M3) including at least one second element selected from the group consisting of Y, Hf, Ge, V, Al, Si, Mn, and Co; and (iv) at least one metal (M4) selected from the group consisting of Mo, Ti, Cr, W, and Cu; and has a composition containing less than 50 wt% of the molybdenum oxide (M1) relative to the total weight of the sintered body.

[0043] Conventional molybdenum oxide targets using molybdenum oxide (M1), the main component, in an excess of 60 wt% or more mainly exhibited only low-reflection characteristics, and had poor low-resistance characteristics and heat resistance.

[0044] In contrast, in the present invention, the content of molybdenum oxide (M1) is relatively reduced, and a first metal oxide (M2) dopant having excellent chemical resistance and heat resistance, a second metal oxide (M3) dopant improving low-reflection and low-resistance characteristics, and a metal (M4) dopant for improving electrical characteristics are adopted, and the contents (M2, M3, M4) of these are organically controlled to form an optimized composition, thereby simultaneously securing low-reflection characteristics, low-resistance characteristics, and excellent heat resistance.

[0045] Below, each component is described in detail.

[0046] Molybdenum oxide (M1) included in the oxide sintered body according to the present invention is a main component constituting the sintered body.

[0047] Molybdenum oxide (M1) is a component that has a form in which oxygen is bonded to molybdenum, such as MoO2, MoO3, and MoO4. In the present invention, at least one of MoO2 and MoO3 is included as the molybdenum oxide. At this time, if the amount of MoO3 is large, the sintered density is low, and the chemical stability is poor when deposited as a thin film, so it is preferable to include MoO2 as an essential component.

[0048] Meanwhile, the oxide sintered body according to the present invention may include stoichiometric molybdenum oxides such as MoO2 and MoO3 based on the final product. However, substoichiometric molybdenum oxides, such as Mo4O 11 , Mo 17 O 47 , Mo5O 14 , Mo8O 23 , Mo9O 26 , and Mo 18 O 52 At least one or more of the above are substantially non-containing. Here, "substantially non-containing" means that only an inevitable impurity content of 2.0 wt% or less, specifically 1.0 wt% or less, and more specifically 0.5 wt% or less, relative to 100 wt% of the oxide sintered body may be present.

[0049] The above molybdenum oxide (M1) may be included in an amount of less than 50 wt% based on 100 wt% of the oxide sintered body, and specifically, may be included in an amount of 40 wt% or more and less than 50 wt%.

[0050] One of the additive components included in the oxide sintered body according to the present invention is a first metal oxide (M2) including at least one first element selected from the group consisting of Nb, Ta, Zr, Ti, Sn, and W.

[0051] This first metal oxide (M2) is an oxide dopant that improves chemical resistance and heat resistance characteristics, and the chemical resistance and heat resistance characteristics of molybdenum oxide (M1) can be increased by adding the first metal oxide. The first metal oxide (M2) is not particularly limited as long as it is a component having oxygen bonded to at least one element (A1) among Nb, Ta, Zr, Ti, Sn, and W, and may include, for example, at least one selected from the group consisting of Nb2O5, Ta2O5, ZrO2, TiO2, SnO2, and WO3. Preferably, it may be Nb2O5, Ta2O5, or a mixture thereof. In the following description, the first metal oxide component is symbolized as M2.

[0052] The above first metal oxide (M2) may be included in an amount of 20 to 25 wt% based on 100 wt% of the oxide sintered body, and specifically, may be included in an amount of 20.5 to 24.5 wt%.

[0053] Another additive component included in the oxide sintered body according to the present invention is a second metal oxide (M3) including at least one second element selected from the group consisting of Y, Hf, Ge, V, Al, Si, Mn, and Co.

[0054] This second metal oxide (M3) is a dopant for improving low-reflection and low-resistance characteristics, and the low-reflection characteristics and low-resistance characteristics of molybdenum oxide (M1) can be simultaneously improved by adding the second metal oxide (M3). The second metal oxide (M3) is not particularly limited as long as it is a component in which oxygen is bonded to at least one element (A2) among Y, Hf, Ge, V, Al, Si, Mn, and Co, and may include, for example, at least one selected from the group consisting of Y2O3, HfO2, GeO2, V2O5, Al2O3, SiO2, MnO2, and Co3O4. Preferably, it may be Y2O3, HfO2, or a mixture thereof. In the following description, the second metal oxide component is symbolized as M3.

[0055] The above second metal oxide (M3) may be included in an amount of 1 to 10 wt% based on 100 wt% of the oxide sintered body, and specifically, may be included in an amount of 3 to 8 wt%.

[0056] Another additive component included in the oxide sintered body according to the present invention is at least one metal (M4) selected from the group consisting of Mo, Ti, Cr, W, and Cu.

[0057] This metal (M4) is a metal dopant that assists the sintering of molybdenum oxide, exhibits a density-increasing effect, and improves electrical properties. By adding the metal, the low-resistance, chemical resistance, and heat resistance properties of molybdenum oxide can be improved. In the following description, at least one component among Mo, Ti, Cr, W, and Cu is symbolized and represented as M4.

[0058] The above metal (M4) may be included in an amount of 20 to 40 wt% based on 100 wt% of the oxide sintered body, and specifically, may be included in an amount of 25 to 35 wt%.

[0059] The metal oxide sintered body including the aforementioned molybdenum oxide (M1), the first metal oxide (M2), the second metal oxide (M3), and the metal (M4) has a composition including 40 wt% or more and less than 50 wt% of the molybdenum oxide (M1); 20 to 25 wt% of the first metal oxide (M2); 1.0 to 10 wt% of the second metal oxide (M3); and 20 to 40 wt% of the metal (M4), based on 100 wt% of the sintered body.

[0060] For example, the oxide sintered body may have a weight % ratio of (i) (M1+M2) / (M2) of 1.4 to 1.7%, specifically 1.5 to 1.65%, and more specifically 1.5 to 1.625%.

[0061] As another specific example, the oxide sintered body may have a weight % ratio of (ii) (M1+M2+M3+M4) / (M1+M2) of 1.2 to 1.6%, specifically 1.25 to 1.58%, and more specifically 1.3 to 1.55%.

[0062] The oxide sintered body according to the present invention, which is configured as described above, has a relative density of 95% or more, and the upper limit thereof is not particularly limited. In addition, the resistivity of the oxide sintered body is 1×10 -2 Ωcm or less, and its lower limit is not particularly limited. And the size of the crystal grains included in the oxide sintered body is not particularly limited, and may be, for example, 1 to 20 ㎛, and specifically, 1 to 10 ㎛.

[0063] In addition, a sputtering target according to another embodiment of the present invention includes an oxide sintered body having the aforementioned molybdenum oxide as a main component; and a backing plate bonded to one surface of the sintered body to support the sintered body.

[0064] Here, the backing plate is a substrate that supports a sintered body for a sputtering target, and any conventional backing plate known in the art can be used without limitation. At this time, the material constituting the backing plate and its shape are not particularly limited.

[0065] <Method for manufacturing oxide sintered body and sputtering target>

[0066] Hereinafter, a method for manufacturing an oxide sintered body and a sputtering target according to one embodiment of the present invention will be described. However, the present invention is not limited to the manufacturing method described below, and each process step may be modified or selectively combined as needed.

[0067] A preferred embodiment of the above manufacturing method may include: (i) a first step of mixing molybdenum oxide (M1), a first metal oxide (M2), a second metal oxide (M3), and at least one metal (M4); (ii) a second step of sintering the mixed raw material powder; (iii) a third step of processing a sintered body obtained by sintering the material powder; and (iv) a fourth step of bonding the sintered body to a backing plate to complete the target.

[0068] Hereinafter, the above manufacturing method is explained in detail by each process step.

[0069] (i) Powder mixing step

[0070] First, in the first step, a molybdenum oxide powder (M1); a first metal oxide powder (M2) of at least one of Nb2O5, Ta2O5, ZrO2, TiO2, SnO2, and WO3; a second metal oxide powder (M3) of at least one of Y2O3, HfO2, GeO2, V2O5, Al2O3, SiO2, MnO2, and Co3O4; and at least one metal (M4) of Mo, Ti, Cr, W, and Cu are weighed and mixed to a desired chemical composition.

[0071] As a specific example of the first step, the main component, molybdenum oxide powder (M1), and the first metal oxide powder (M2) with excellent chemical resistance and heat resistance are added. At this time, the weight ratio (M1+M2) / (M2) is measured so that it is 1.4 to 1.7%, specifically 1.5 to 1.65%, and more specifically 1.5 to 1.625%.

[0072] Next, a second metal oxide (M3) powder for improving low-reflection and low-resistance characteristics and a metal (M4) powder for improving electrical characteristics are added to the mixed raw material powder. At this time, the (M1+M2+M3+M4) / (M1+M2) weight % ratio is weighed to be 1.2 to 1.6%, specifically 1.25 to 1.58%, more specifically 1.3 to 1.55%, and most specifically 1.33 to 1.54%.

[0073] After weighing, the mixed powder undergoes a dry ball milling process using zirconia balls.

[0074] Zirconia balls can be weighed at 1 to 3 times the amount of powder, and ball milling can be performed at a speed of 100 to 300 rpm for 7 to 9 hours, for example, 8 hours. After dry ball milling, sieving can be performed to complete powder mixing.

[0075] (ii) Sintering stage

[0076] In the second step, to sinter the mixed powder, a carbon sheet is wrapped around the inside of the carbon mold and the lower punch to a thickness of 0.1 to 0.5 mm, and 200 to 400 g of the mixed powder is loaded. After loading the powder, the carbon sheet is covered and the upper punch is installed.

[0077] Once the sintering mold is prepared through this process, the mold can be loaded into a hot press and the sintering process can be performed. The temperature rise rate during sintering is 2 to 10°C / min, and the maximum heat treatment temperature can be maintained at 1,200 to 1,400°C for 1 to 3 hours. The pressure at the temperature rise and maintenance temperature can be maintained at 17 to 30 MPa.

[0078] (iii) Processing stage

[0079] In the third step, the sintered body is removed and processed.

[0080] Specifically, after removing the sintered body, the carbon sheets on the upper and lower parts of the target are removed, and then the surface of the target is polished. To remove the carbon sheets, the upper and lower parts can be machined by at least 1 mm.

[0081] (iv) Bonding stage

[0082] In the fourth step, the processed sintered body is bonded to the backing plate.

[0083] Indium can be used as an adhesive, and it is desirable to have a bonding rate of 95% or higher.

[0084] A metal oxide target can be manufactured through the aforementioned process. The target density of the manufactured target is preferably 95% or higher, and more specifically, 98.0% or higher.

[0085] <Oxide thin film>

[0086] Another example of the present invention is a metal oxide thin film deposited using the aforementioned molybdenum oxide target. This metal oxide thin film can be formed by performing sputtering using the aforementioned sintered body as a target material.

[0087] Although the above oxide thin film may have slight differences in composition depending on the deposition atmosphere, it is manufactured by sputtering the above oxide target, so its composition is substantially the same as that of the target. Accordingly, it has high-density characteristics exceeding 95% relative density and 1×10 -2 An oxide film with excellent resistivity characteristics of less than Ωcm can be formed. In addition, by adding specific metal oxides and metals to the main raw material, molybdenum oxide, within a predetermined range, and optimizing the molybdenum oxide ratio and composition, low reflection, low resistance, and heat resistance characteristics can all be improved.

[0088] For example, the oxide thin film may have a light reflectance (R1) of 11.0% or less for a wavelength of 550 nm before heat treatment, and a light reflectance (R2) of 11.0% or less for a wavelength of 550 nm after heat treatment at a temperature of 350°C for 30 minutes or more. More specifically, the oxide thin film may have a light reflectance (R1) of 10.0% or less for a wavelength of 550 nm before heat treatment, and a light reflectance (R2) of 10.0% or less for a wavelength of 550 nm after heat treatment. In this case, the lower limit of the light reflectance is not particularly limited.

[0089] For another specific example, the difference (R2-R1) between the light reflectance (R2) after heat treatment at a temperature of 350°C and for 30 minutes or more and the light reflectance (R1) before heat treatment may be 1.0% or less, specifically 0.3% or less, and more specifically 0.1% or less.

[0090] The aforementioned optical reflectance (R 1, The lower limit of the change in light reflectance (ΔR = R2- R1) and the light reflectance according to the present invention is not particularly limited. In addition, the light reflectance according to the present invention means that it is measured based on an average wavelength of 360 to 740 nm and / or a wavelength of 550 nm, and is not particularly limited thereto.

[0091] The metal oxide thin film according to the present invention can be formed (deposited) by a conventional sputtering method known in the art. In this case, sputtering can be performed using DC sputtering.

[0092] The above metal oxide thin film can be used as at least one of the gate layer, source layer, and drain layer of a thin film transistor (TFT). In addition, such a thin film transistor can be used in display devices such as OLED TVs, mobile phones, and tablets.

[0093] As a specific example, the metal oxide thin film according to an embodiment of the present invention can be used as a low-reflection layer under a gate layer. A thin film for such a purpose reduces the reflectivity of the substrate and improves the adhesion of the gate electrode.

[0094] Here, the substrate can be any of a variety of substrates commonly used in display device manufacturing, such as glass, metal, plastic, or plastic film. Specifically, the substrate can be a transparent front panel for an OLED TV, mobile phone, or tablet. Meanwhile, the gate electrode can be formed from a common electrode material, such as copper or silver.

[0095] Thin film deposition is performed at a power density of 1.0 to 2.0 w / cm of DC sputtering. 2 The substrate can be deposited at room temperature under an argon gas (Ar Gas) atmosphere. At this time, the thickness of the metal oxide thin film may be 300 to 500 Å, specifically 350 to 450 Å, but is not particularly limited thereto. In addition, a copper (Cu) thin film can be deposited on the metal oxide thin film. At this time, the copper thin film can be deposited with a thickness of 3000 to 6000 Å. The thin film deposited in this way is measured for reflectance on a glass surface.

[0096] Meanwhile, the measurement of reflectivity can be performed according to a method known in the art. For example, the measurement can be performed on the surface of the substrate on which the metal oxide thin film is formed, and the light reflectivity for an average wavelength of 360 to 740 nm and / or a wavelength of 550 nm is measured. In this case, the light reflectivity is 11.0% or less, and specifically, 10.0% or less, and the lower limit thereof is not particularly limited.

[0097] The metal oxide thin film according to an embodiment of the present invention has excellent heat resistance. This heat resistance evaluation can be performed as follows, but is not particularly limited thereto.

[0098] In order to evaluate the heat resistance of a thin film, a method of heat treating the thin film deposited as described above in an atmosphere of 200 to 400°C for 30 minutes or more can be used. The heat treatment can be performed in a general vacuum heat treatment furnace and / or a hydrogen heat treatment furnace. For example, the heat resistance can be evaluated by observing the change in the characteristics of the thin film after heat treatment at a temperature of 200 to 400°C for 30 minutes or more in a hydrogen heat treatment furnace.

[0099] For example, the difference (R2-R1) between the reflectance after heat treatment (R2) and the reflectance before heat treatment (R1) is approximately 1.0% or less, specifically 0.3% or less, and more specifically 0.1% or less.

[0100] In addition, to evaluate chemical resistance, a method of forming a micro pattern on the formed thin film using a lithography method and observing the cross-section of the formed micro pattern can also be used.

[0101] The above-described oxide thin film can be used in various ways in the manufacture of semiconductor devices, and for example, can be applied for forming wiring or electrodes in the manufacture of semiconductors. In particular, the metal oxide thin film can be used as at least one of a gate layer, a source layer, and a drain layer of a thin film transistor (TFT). When the thin film of the present invention is used as a barrier layer of the source and drain electrodes included in a thin film transistor, the contact resistance can be reduced, and the physical properties of the thin film transistor can be improved by having excellent transparency and a low refractive index.

[0102] The molybdenum oxide sputtering target according to the present invention described above and the oxide thin film formed therefrom simultaneously have low reflection characteristics, low resistance characteristics, and excellent heat resistance characteristics, and thus can suppress the connection resistance with the TFT structure of LCD and OLED, or the electron injection layer of an organic electroluminescent device to a low level. Accordingly, the oxide thin film described above can be applied without limitation to various display devices such as liquid crystal displays or organic electroluminescent display devices, information transmission devices such as flat panel displays such as LCD, PDP, OLED, and LED; surface light source lighting device touch panels such as OLED and LED; mobile phones, tablets, and / or information transmission devices using the same.

[0103] Hereinafter, the present invention will be described in detail through examples. However, the following examples are only illustrative of the present invention, and the present invention is not limited to the following examples.

[0104]

[0105] [Example 1]

[0106] The powder was weighed so that the weight % (wt%) ratio of (MoO2+Nb2O5+Mo+V2O5) / (MoO2+Nb2O5) was 1.54. The weighed powder was put into a 1 L plastic container, and zirconia balls were added in an amount three times the powder amount. 3 to 10 mm zirconia balls were used. After the weighed powder and ball were added, dry mixing was performed in a ball mill machine at a speed of 170 to 230 rpm for 8 hours. The obtained dry powder was pressure-sintered using a hot press. At this time, the internal vacuum condition of the hot press was 10 -2 Sintering was performed at 3 torr, with a heating rate of 3 to 7°C, a maximum temperature of 1,200 to 1,400°C, and a holding time of 1 to 3 hours, and then furnace cooling was performed.

[0107] The metal oxide sintered body of Example 1 obtained as described above has a sintered density of 98.8% and a resistivity of 1.15 × 10 -3It was measured in Ωcm.

[0108]

[0109] [Comparative Example 1]

[0110] The powder was weighed so that the weight % (wt%) ratio of (MoO2+Nb2O5+Mo) / (MoO2+Nb2O5) was 1.42. The weighed powder was placed in a 1 L plastic container, and zirconia balls were added in an amount three times the powder amount. 3 to 10 mm zirconia balls were used. After the weighed powder and balls were added, dry mixing was performed in a ball mill machine at a speed of 170 to 230 rpm for 8 hours. The obtained dry powder was pressure-sintered using a hot press. At this time, the internal vacuum condition of the hot press was 10 -2 Sintering was performed at 3 torr, with a heating rate of 3 to 7°C, a maximum temperature of 1,200 to 1,400°C, and a holding time of 1 to 3 hours, and then furnace cooling was performed.

[0111] The metal oxide sintered body of Comparative Example 1 obtained as above has a sintered density of 98.5% and a resistivity of 4.58 × 10 -3 It was measured in Ωcm.

[0112]

[0113] [Experimental Example 2: Evaluation of Thin Film Properties]

[0114] After forming a thin film using the sintered body manufactured in Example 1 and Comparative Example 1 as a target material, the heat resistance of the thin film was evaluated as follows.

[0115] Specifically, a thin film was fabricated using each sintered body as a low-reflection layer under the gate layer. This thin film is intended to improve the adhesion of the low-reflection and gate electrodes on the substrate (glass).

[0116] The low-reflection thin film was formed by using a DC sputtering target containing the sintered body of Example 1 and Comparative Example 1 at a power density of 0.5 to 3.6 w / cm. 2A thin film was formed by depositing it on a transparent glass substrate under an argon gas atmosphere, and the thin film thickness was deposited to 350 to 450 Å.

[0117] Additionally, a gate electrode was formed on the aforementioned thin film. The gate electrode was formed using a copper (Cu) target using DC sputtering at a power density of 0.5 to 3.6 w / cm. 2 It was formed under an argon gas atmosphere, and the film thickness was deposited at 3,000 to 6,000 Å.

[0118] In this state, the initial reflectance of the thin film on the glass substrate surface was measured, and then the thin film was heat-treated in a vacuum heat treatment furnace at a temperature of 350°C for more than 30 minutes. The reflectance was measured again and the reflectance before and after the heat treatment was compared. The results are shown in Table 1 and Figures 1-2, respectively.

[0119] Target density (%) Sheet resistance (Ω / sq.) Reflectivity of low-reflection molybdenum oxide thin film / Cu thin film (average of 360–740 nm) Reflectivity change before and after heat treatment (R2-R1) Before heat treatment (R1) After heat treatment (R2) Example 198.82.57×10 3 9.9%9.98%0.08Comparative example 198.53.25×10 3 11.7%12.9%1.2

[0120] As shown in Table 1 above, in the case of Comparative Example 1, both the initial reflectance before heat treatment and the reflectance after heat treatment exceeded 10%, and in particular, it was found that the reflectance after heat treatment increased significantly. In contrast, in the case of Example 1, the average reflectance of the thin film before heat treatment was 9.9%, and it was confirmed that the reflectance after heat treatment in a hydrogen heat treatment furnace at 350°C for 30 minutes or more to secure the thermal stability of the thin film also had excellent thin film characteristics with almost no change from the initial reflectance.

[0121] Through the above-described results, it was found that the oxide sintered body of the present invention simultaneously secured low reflection, low resistance, and excellent heat resistance.

Claims

1. Molybdenum oxide (M1); A first metal oxide (M2) comprising at least one first element selected from the group consisting of Nb, Ta, Zr, Ti, Sn, and W; A second metal oxide (M3) comprising at least one second element selected from the group consisting of Y, Hf, Ge, V, Al, Si, Mn, and Co; and Containing at least one metal (M4) selected from the group consisting of Mo, Ti, Cr, W, and Cu; An oxide sintered body containing molybdenum oxide (M1) in an amount of less than 50 wt% relative to the total weight of the sintered body.

2. In paragraph 1, The above molybdenum oxide (M1) is an oxide sintered body including at least one of MoO2 and MoO3.

3. In paragraph 1, The above oxide sintered body is Mo4O 11 , Mo 17 O 47 , Mo5O 14 , Mo8O 23 , Mo9O 26 , and Mo 18 O 52 An oxide sintered body substantially free of at least one substoichiometric molybdenum oxide selected from the group consisting of:

4. In paragraph 1, An oxide sintered body in which the above molybdenum oxide (M1) is contained in an amount of 40 wt% or more and less than 50 wt% based on 100 wt% of the oxide sintered body.

5. In paragraph 1, An oxide sintered body in which the first metal oxide (M2) is included in an amount of 20 to 25 wt% based on 100 wt% of the oxide sintered body.

6. In paragraph 1, An oxide sintered body in which the second metal oxide (M3) is included in an amount of 1 to 10 wt% based on 100 wt% of the oxide sintered body.

7. In paragraph 1, An oxide sintered body, wherein the metal (M4) is contained in an amount of 20 to 40 wt% based on 100 wt% of the oxide sintered body.

8. In paragraph 1, The above oxide sintered body is, (i) the weight % ratio of (M1+M2) / (M2) is 1.4 to 1.7%, (ii) An oxide sintered body having a weight % ratio of (M1+M2+M3+M4) / (M1+M2) in the range of 1.2 to 1.6%.

9. In paragraph 1, The resistivity is 1×10 -2 Ωcm or less, Oxide sintered body having a relative density of 95% or more.

10. A sputtering target comprising an oxide sintered body according to any one of claims 1 to 9.

11. An oxide film formed from the sputtering target of clause 10.

12. In paragraph 11, The optical reflectance (R1) for a wavelength of 550 nm before heat treatment is 11.0% or less. An oxide thin film having a light reflectance (R2) of 11.0% or less for a wavelength of 550 nm after heat treatment at a temperature of 350°C for 30 minutes or longer.

13. In paragraph 12, An oxide thin film, wherein the difference (R2-R1) between the light reflectance (R2) after heat treatment at a temperature of 350℃ for 30 minutes or longer and the light reflectance (R1) before heat treatment is 1.0% or less.

14. A thin film transistor in which the thin film of clause 11 is used as any one of a gate layer, a source layer, and a drain layer.

15. A display device comprising the thin film of clause 11.

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