TW201404909A - Zinc oxide-based sputtering target, method of manufacturing the same, thin-film transistor having barrier layer deposited using the same, and method of manufacturing the thin-film transistor - Google Patents

Abstract

The present invention disclose a zinc oxide (ZnO)-based sputtering target, a method of manufacturing the same, a thin-film transistor (TFT) having a barrier layer deposited using the same, and a method of manufacturing the thin-film transistor. The zinc oxide-based sputtering target includes a sinter containing zinc oxide doped with gallium oxide, the content of the gallium oxide ranging, by weight, from 10 to 50 percent of the sinter, and a backing plate bonded to the rear surface of the sinter to support the sinter. The zinc oxide-based sputtering target can be subjected to direct current (DC) sputtering, and improve the contact and etching characteristics of a barrier layer that is deposited using the same.

Description

Zinc oxide sputtering target, method for producing the same, thin film transistor having a barrier layer deposited thereon, and method for manufacturing thin film transistor

Cross-references to related applications

 The priority of Korean Patent Application No. 10-2012-0068354 and 10-2012-0155995 filed on June 26, 2012, and December 28, 2012, the entire contents of which is incorporated herein by reference. As a reference.

 The present invention relates to a zinc oxide (ZnO)-based sputtering target, a method of manufacturing the same, a thin film transistor having a barrier layer deposited thereon, and a method of manufacturing the thin film transistor, and more specifically, a A zinc oxide-based sputtering target that is subjected to direct current (DC) sputtering and improves the contact and etching characteristics of the barrier layer deposited thereon, a method of manufacturing the same, a thin film transistor having a barrier layer using the deposition thereof, and a thin film transistor The method.

 A liquid crystal display (LCD) or an electroluminescent display (EL) has superior display performance and consumes less power. Therefore, liquid crystal displays or electroluminescent displays are widely used in display devices for mobile phones, personal computers (PCs), word processors, televisions, and the like. Such displays operate using a transistor, that is, a thin film transistor (TFT) formed of a fine pattern. The fine pattern of the thin film transistor is obtained by forming a film from different materials by successive etching using various deposition methods. These fine patterns are separated into a gate electrode, a source electrode, and a drain electrode. When Al, Mo, or the like is used as an electrode material, a material having high electrical conductivity is required as a display having a higher resolution to achieve higher image quality. As a means, Cu which has high electrical conductivity in a metal material and is inexpensive as an electrode material has been attracting attention. The use of Cu as an electrode material was performed by research organizations and companies.

 Since the Cu electrode has excellent electrical conductivity, it can achieve uniform characteristics when it is thinner than other electrodes. Therefore, it can reduce the tact time of processing, thereby reducing manufacturing costs. In addition, the Cu electrode is suitable for high-profile products that require high electrical conductivity.

 However, Cu of the Cu electrode may diffuse into the upper layer or the lower layer made of other materials, or may react with such other materials due to its good reactivity. At this time, the performance of the thin film transistor is often deteriorated and is problematic. In particular, during the deposition of a protective layer which is considered to be a passivation on the source electrode and the drain electrode, Cu may oxidize, thereby deteriorating the contact between the Cu and the protective layer. Therefore, the protective layer may be peeled off or the performance of the thin film transistor may be deteriorated and is problematic.

 Therefore, it is more important to introduce a barrier layer which can be etched and reduce the diffusion of Cu into or react with other layers in an etching process for patterning Cu to form a Cu electrode.

 The information disclosed in the Background section of the present invention is provided only for a better understanding of the background of the present invention and should not be construed as an acknowledgment or any form of suggestion that such information is formed prior to those of ordinary skill in the art. technology.

Related field documentation

 Patent Document 1: Korean Patent Application No. 2010-0107571 (October 6, 2010)

 Various aspects of the present invention provide a zinc oxide (ZnO)-based sputtering target that can be subjected to direct current (DC) sputtering and improve contact and etching characteristics of a barrier layer deposited using the same, a method of manufacturing the same, and a deposition method using the same A thin film transistor of a barrier layer, and a method of manufacturing a thin film transistor.

 In one aspect of the present invention, a zinc oxide-based sputtering target includes: a sintered body comprising zinc oxide doped with gallium oxide, the content of gallium oxide being 10 to 50% by weight of the sintered body; and bonding to The back surface of the sinter is supported to support the backing of the sinter.

 According to an embodiment of the present invention, the resistance of the zinc oxide-based sputtering target may be 100 Ω·cm or less than 100 Ω·cm.

 The zinc oxide-based sputtering target can be a target that can be subjected to direct current (DC) sputtering.

The power applied during DC sputtering can be between 0.1 and 8 W/cm ² .

The zinc oxide-based sputtering target may have a density of 5.3 g/cm ³ or more than 5.3 g/cm ³ .

 The aggregate of gallium oxide may be distributed in the sintered body in a size of 1 μm or less.

 The sinter may comprise at least one selected from the group consisting of a Group III element and a Group IV element.

 In another aspect of the invention, a method of fabricating a thin film transistor comprising an electrode and an oxidized semiconductor layer is provided. The method includes the step of depositing a barrier layer between the electrode and the oxidized semiconductor layer using the above zinc oxide-based sputtering target.

 According to an embodiment of the invention, the barrier layer may have a crystal size between 10 and 5000 Å.

 The barrier layer can be deposited to a thickness of between 30 and 50 nm.

The resistance of the barrier layer can range from 100 to 1 x 10 ^-4 Ω·cm.

 The electrode can be made of Cu.

 In a further aspect of the invention, a method of making a zinc oxide based sputtering target is presented. The method comprises the steps of: preparing a slurry by adding gallium oxide to zinc oxide, the content of gallium oxide being between 10 and 50% by weight of the slurry; forming a granular powder by drying the slurry; molding the granular powder Formed as agglomerates; and the sintered agglomerates are sintered.

 According to an embodiment of the present invention, the step of preparing a slurry may include a first dispersion step of mixing a mixed solution of gallium oxide with distilled water and a first dispersant followed by wet grinding; and mixing the suspension generated by the first dispersion step A second dispersion step of forming a slurry with the second dispersant and zinc oxide followed by wet milling.

 The first dispersion step may be performed by wet milling such that the average particle size of the gallium oxide is between 0.2 and 0.6 μm.

 The first dispersion step may be added to the first dispersant in an amount of from 0.1 to 2 weight percent of the gallium oxide.

 The second dispersion step may be added to the second dispersant in an amount of from 0.3 to 2.5 weight percent of the zinc oxide.

 The second dispersion step can be controlled such that the average particle size of the slurry is between 0.1 and 0.5 μm.

 The step of preparing the slurry may further comprise adding a binder to the slurry.

 The step of sintering the agglomerates may comprise sintering the agglomerates in an air or oxygen environment at a temperature between 1400 and 1600 °C.

 In still another aspect of the present invention, a thin film transistor including an electrode, a barrier layer, and an oxidized semiconductor layer is proposed. The barrier layer is disposed between the electrode and the oxidized semiconductor layer, and comprises zinc oxide doped with gallium oxide, and the content of gallium oxide is 5 to 40% by weight of the barrier layer.

 According to an embodiment of the present invention, a high-density zinc oxide-based sputtering target that can be stably DC-sputtered can be fabricated by doping zinc oxide with gallium oxide.

In addition, during the fabrication of the thin film transistor, when the SiO _x -based oxide protective layer is deposited on the gate electrode, the source electrode and the drain electrode which can be made of Cu using a sputtering target, it can be formed by blocking The layer avoids CuO _x formation, thereby improving the contact characteristics between the Cu electrode and the protective layer. A barrier layer applied to the display but having a high transmittance can be deposited on the Cu electrode, that is, between the Cu electrode and the oxidized protective layer.

 Further, it is possible to deposit a barrier layer using a zinc oxide-based sputtering target. The barrier layer can be etched in synchronization with the Cu electrode, and the etching speed can be easily adjusted so that neither undercut nor off angle is formed. The barrier layer does not cause problems caused by etching the Cu electrode or the like. Therefore, the barrier layer can contribute to the convenience and simplicity of the thin film transistor manufacturing process. In other words, the barrier layer deposited using the zinc oxide-based sputtering target according to the present invention requires an additional patterning process and can be patterned with the Cu electrode in the process of patterning the Cu electrode.

 Other features and advantages of the invention will be set forth in the <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt;

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 1 is an electron probe micro-analyzer (EPMA) image showing a sintered body produced by a method for manufacturing a zinc oxide-based sputtering target according to an embodiment of the present invention;

 2A and 2B are diagrams showing the presence or absence of a barrier layer deposited on a zinc oxide-based sputtering target according to an embodiment of the present invention in a secondary ion mass spectrometer (SIMS). a schematic diagram of the results of the analysis;

 3A and 3B are transmission electron microscopy (TEM) images taken to compare etching characteristics according to the composition of the barrier layer;

 4A and 4B are views of an image taken by using an electron microscope for observing the influence of a barrier layer deposited by a zinc oxide-based sputtering target according to an embodiment of the present invention on Cu oxidation;

 Figs. 5A and 5B are views for observing an image taken by an electron microscope using a resist layer deposited by a sputtering target made of a comparative example, that is, a sputtering target made of a Cu-Mn alloy, for the influence of Cu oxidation.

 A more detailed reference will now be made to a zinc oxide (ZnO)-based sputtering target according to the present invention, a method for producing the same, a thin film transistor (TFT) having a barrier layer using the deposition thereof, and a method of manufacturing a thin film transistor. The embodiments are illustrated in the drawings and described hereinafter to enable those skilled in the art to practice the invention.

 Throughout the drawings, the same reference numerals and signs are used throughout the drawings to refer to the In the following description of the present invention, the detailed description of the known functions and the components of the present invention will be omitted when the subject matter of the present invention is unclear.

 The zinc oxide-based sputtering target according to an embodiment of the present invention is a target in which a zinc oxide-based barrier layer is deposited in a process for fabricating a thin film transistor, and the thin film transistor forms a member of a flat panel display using a Cu electrode. For example, the zinc oxide-based barrier layer prevents Cu diffusion for the gate electrode, the source electrode and the gate electrode, and the metal line from acting as an oxide layer on the protective layer or reacting with the oxide layer. At the same time, the zinc oxide-based barrier layer can be etched in synchronization with Cu under the existing etching conditions due to high penetrability. In addition, it is easy to adjust the etching speed so that undercuts or tips are not formed.

 The zinc oxide-based target contains a sintered body and a back sheet.

 The sinter comprises zinc oxide doped with gallium oxide, and the content of gallium oxide is between 5 and 40% by weight of the zinc oxide. When less than 5 weight percent of gallium oxide is added, the zinc oxide-based barrier layer deposited using the zinc oxide-based sputtering target has low electrical resistance and is thus suitable for use in a transparent conductive film. However, the etching speed is too fast during the manufacture of the thin film transistor, and the etching causes corrosion and declination due to undercutting. In contrast, when more than 40 weight percent of gallium oxide is added, it can achieve a target that can be subjected to direct current sputtering (DC). More preferably, gallium oxide is added in an amount of from 15 to 30% by weight.

 According to an embodiment of the present invention, gallium oxide is uniformly distributed in zinc oxide, and the gallium oxide aggregate is distributed in a size of 1 μm or less in the sintered body. Therefore, since the sintered body has a local resistance uniformity of 10% or less and the composition uniformity is from -10% to +10%, the same feature can be achieved by using a barrier layer deposited by the target. Further, according to an embodiment of the present invention, the sinter may include at least one selected from the group consisting of Group III elements such as In and Al, and a plurality of Group IV elements such as Zr, Si, and Sn.

 The back sheet is a member that functions to support the sintered body, and can be made of Cu, preferably, oxygen-free Cu, Ti, or stainless steel having superior electrical conductivity and thermal conductivity. The back sheet is bonded to the back surface of the sintered body using a bonding material made of, for example, In to form a zinc oxide-based sputtering target.

The zinc oxide-based sputtering target including the sintered body and the back sheet has a resistance of 100 Ω·cm or less. Further, the zinc oxide-based sputtering target according to the embodiment of the present invention has a high density of 5.3 g/cm ³ . Therefore, the zinc oxide-based sputtering target is characterized in that discharge can be stably performed without abnormal discharge during DC sputtering when high power intensity is applied, for example, when an applied power intensity is between 0.1 and 8 W/cm ² . In addition, since the zinc oxide-based sputtering target according to the embodiment of the present invention has less blackening which is common to the common sputtering target, the particles generate minimal defects in the sputtering deposition process. A zinc oxide-based sputtering target having such features can be achieved by controlling the manufacturing process, which will be described in more detail below with respect to the method of fabricating a zinc oxide-based sputtering target.

As described above, the zinc oxide-based sputtering target according to the embodiment of the present invention is used for depositing a zinc oxide-based barrier layer of a thin film transistor. The thin film transistor includes a Cu layer forming a gate electrode, a source electrode and a drain electrode, and a wiring, and an oxide layer or a protective layer deposited on the Cu layer. When an oxide layer made of, for example, SiO _x is deposited on the Cu layer, Cu in the Cu layer reacts with oxygen to form CuO _x . When the CuO _x is formed in the reaction Cu, a Cu layer discoloration (discolors) and the ability of the Cu layer in contact with the oxide layer deteriorates, so that the oxide layer peeled off or deteriorated characteristics of thin film transistors. Therefore, during the production of the thin film transistor, when the zinc oxide-based barrier layer is deposited on the Cu layer using the zinc oxide-based sputtering target according to the embodiment of the present invention, it can reduce the reaction between the Cu layer and the oxide layer. At this time, the barrier layer deposited using the zinc oxide-based sputtering target according to the embodiment of the present invention has a crystal size of 10 to 5000 Å. Further, the barrier layer may be deposited to a thickness of between 30 and 50 nm. In this case, the resistance of the barrier layer is between 100 and 1 x 10 ^-4 Ω·cm. In order to achieve the characteristics of such barrier layers, it is preferred that the barrier layer be deposited using a zinc oxide-based sputtering target according to an embodiment of the present invention, and Ar gas and oxygen are mixed at a predetermined ratio during sputtering.

 Although the zinc oxide-based sputtering target according to the embodiment of the present invention can form a single-phase barrier layer or a multi-phase barrier layer depending on manufacturing conditions, a barrier layer composed of a hexagonal layered compound can be formed substantially. The barrier layer deposited using the zinc oxide-based sputtering target is easily etched using a weak acid because the crystal is oriented along the c-axis in the zinc oxide-based crystal structure. Therefore, it is easy to control the etching rate by adjusting the etching solvent concentration and/or adjusting the composition of the target. Therefore, in a batch process using an existing etching solution for etching a solution of Cu, the barrier layer can be etched together with the Cu layer without additional processing. This can facilitate the convenience and simplicity of the thin film transistor manufacturing process. Here, in order to improve the etching characteristics of the barrier layer, the deposition barrier layer may be heat-treated at a temperature of 200 to 400 ° C for 10 to 120 minutes.

 A method of manufacturing a zinc oxide-based sputtering target according to an embodiment of the present invention will be described hereinafter.

 In order to realize all the characteristics of the barrier layer formed by depositing the above-described zinc oxide-based sputtering target according to the embodiment of the present invention, the manufacturing conditions for the zinc oxide-based sputtering target must be highly controlled. To this end, a method of manufacturing a zinc oxide-based sputtering target according to an embodiment of the present invention includes a slurry preparation step, a drying step, a molding step, and a sintering step (sintering) Step).

 The slurry preparation step is a step of producing a slurry by adding gallium oxide to zinc oxide, and the weight percentage of gallium oxide is between 10 and 50% by weight of the slurry. The slurry preparation step can be divided into a first dispersion step and a second dispersion step.

 First, in the first dispersion step, gallium oxide is mixed in a mixed solution in which distilled water and a dispersant are mixed, and wet milling is performed so that the average size (size) of the dispersed particles is from 0.1 to 0.8 μm. The amount of the dispersant added may range from 0.1 to 2 weight percent of the gallium oxide. At this time, the dispersing agent in the suspension formed by the wet grinding must have a structure which can be easily adsorbed on the surface of the gallium oxide and the surface of the zinc oxide to be added in the subsequent process. For this purpose, organic acids such as citric acid, polycarboxylic acid and the like can be used as a dispersing agent. The dispersant needs to maintain the pH of the suspension to achieve high dispersion characteristics of the zinc oxide particles and the gallium oxide particles. For this purpose, the dispersing agent is, for example, a polycarboxylate. For example, a polyacrylic acid ammonium salt, a polycarboxylic acid amine salt or the like can be used. In this manner, the first dispersion step disperses gallium oxide.

 Thereafter, in the second dispersion step, zinc oxide is added to the suspension in which gallium oxide is dispersed, so that the weight percentage of gallium oxide is from 5 to 40% by weight, preferably from 15 to 30% by weight, and the dispersant is added. In the mixture, the dispersant is present in an amount of from 0.3 to 2.5 weight percent of the zinc oxide to form a slurry. This slurry is wet milled so that the average size of the particles is between 0.1 and 0.5 μm. The amount of dispersant to be added is closely related to the average particle size of the slurry. In particular, when the dispersion conditions and the particle size ratio are not satisfied, zinc oxide and gallium oxide which have no electrical properties tend to adhere to the sintered body formed by the subsequent process, thereby remarkably increasing the local resistance of the sintered body. The result may interfere with reliable DC sputtering or end products of the zinc oxide-based sputtering target and have serious side effects on the uniformity of the composition of the deposited thin film transistor. Further, in this embodiment of the invention, the size of the dispersed particles of the gallium oxide and the slurry system are closely related to the sintering temperature. When the dispersed particle size is not controlled within the above range, zinc oxide may cause abnormal volatilization during thermal sintering.

 When the second dispersion step is completed, a binder is added to the resulting slurry. A binder is added to the treatment of the shaped slurry after the dry slurry is a powder to maintain the strength of the compact. The binder can be carried out by using polyvinyl alcohol (polyvinyl glycol) or the like. The binder may be added in an amount of from 0.01 to 5 weight percent, and is preferably from 0.5 to 3% by weight of each gallium oxide and zinc oxide powder in the slurry. The amount of the binder added has a large influence on the sintered density of the sintered body. When the content of the binder added exceeds this range, the molding density is lowered in the process of shaping the granular powder, resulting in a decrease in the sintered density. The reduced sintered density indicates that pores which cause local high electrical resistance are formed in the sintered body. This also acts as a bonding factor for the manufacture of DC-sputterable zinc oxide-based sputtering targets.

 The reason why the wet grinding is performed in a progressive manner in the embodiment of the present invention is as follows. Since the dried raw powders have different average particle sizes and different levels of hardness and cohesion, it is difficult to control the raw material materials when the materials of the dried raw material powder are mixed together and coarsely wet-ground. The powder has the expected particle size. Next, during the manufacture of the sinter, gallium oxide is not uniformly distributed in the zinc oxide matrix and locally localized clustering occurs, thereby deteriorating the electrical and mechanical properties of the target. Therefore, in order to overcome this problem, the slurry preparation step is performed in a progressive manner by introducing impurities into the water system in order to uniformly distribute the particles according to the desired particle size, and then finally adding zinc oxide to the resulting mixture. The zinc oxide is distributed and the gallium oxide is uniformly mixed with the zinc oxide. That is, the slurry preparation step is divided into a first dispersion step and a second dispersion step.

 The subsequent drying step is a step of forming a granular powder by drying the slurry. In this step, it is possible to produce a granulated powder by drying the slurry by a spray drying method.

 Next, the shaping step is a step of molding the granulated powder into agglomerates. This step uses a cold press (hydraulic press) and a cold isostatic pressing (CIP) to make the granulated powder agglomerate.

The subsequent sintering step is a step in which the agglomerates are sintered. The sintering step sinters the agglomerates in an air or oxygen atmosphere at a temperature of 1400 to 1600 °C. The sintering temperature as described above indicates that the resistance of the target is controlled to a temperature of between 1×10 ^-3 and 50 Ω, wherein DC sputtering can be used in the process of manufacturing a gallium oxide doped zinc oxide-based sputtering target. A sintering step or the like can be performed to produce high density and low electrical resistance.

Finally, when the sintered body formed by this method is bonded to the back sheet, the zinc oxide-based sputtering target according to the embodiment of the present invention is completed. The zinc oxide-based sputtering target manufactured according to the embodiment of the present invention has an electric resistance of 100 Ω·cm or less and 100 Ω·cm, so that the barrier layer can be reliably formed on the Cu layer when a thin film transistor is fabricated by DC sputtering. on. The power intensity of the DC sputtering introduced at the time of forming the barrier layer can be freely adjusted between 0.1 and 8 W/cm ² . Although the glow discharge may be outside this range, there is a high probability that defects such as abnormal power generation may occur and very high probability that cracks may form in the target. Therefore, beyond this range does not apply to this industry.

 Hereinafter, a thin film transistor having a barrier layer deposited using a zinc oxide-based sputtering target according to an embodiment of the present invention and a method of manufacturing a thin film transistor will be described in detail.

The present invention discloses a thin film transistor comprising an electrode, a barrier layer and an oxidized semiconductor layer. The barrier layer is disposed between the electrode and the oxidized semiconductor layer. When the film, that is, the barrier layer is deposited by DC sputtering using a zinc oxide-based sputtering target manufactured according to an embodiment of the present invention, the resistance of the barrier layer may be between 100 and 1×10 depending on the thickness of the composition at 30 nm. ^-4 Ω·cm. When the barrier layer is deposited using a zinc oxide-based sputtering target, the basic vacuum of the chamber must be controlled between 1×10 ^-7 and 1×10 ^-5 torrs. Although high quality films can be produced at a high degree of vacuum, maintaining an ultra-high vacuum level in industrial facilities results in increased costs. Therefore, when the degree of vacuum is maintained at the above level, a zinc oxide-based sputtering target manufactured according to an embodiment of the present invention can be used to form a high-quality barrier layer. In addition, a reactive gas such as oxygen can be supplied with the Ar gas to control the crystallinity and electrical resistance of the barrier layer during deposition. After deposition as described above, the barrier layer may be heat treated at a temperature between 200 and 400 °C.

 In the barrier layer deposited or heat-treated using the zinc oxide-based sputtering target manufactured according to the embodiment of the present invention as described above, during etching of the thin film transistor, when etching is performed using a chemical etchant for etching the Cu layer The undercut or the off-angle are not formed on the lower layer and the upper film layer. When the etching rate is too slow, the mass yield is lowered. In contrast, when the etching speed is too fast, it is difficult to control the process. When the barrier layer is formed by etching using a zinc oxide-based sputtering target according to an embodiment of the present invention, the etching can be controlled at an appropriate speed. This can thus prevent problems caused by non-uniform etching.

 The method of manufacturing a thin film transistor according to the embodiment, and the comparison between the thin film transistors according to the examples and the comparative examples are explained in the following examples.

Example 1

 Gallium oxide having an average particle size of 4 μm was added to distilled water in an amount of 20% by weight of the zinc oxide-based sputtering target, wherein the dispersing agent was added in an amount of 1.0% by weight of gallium oxide. The resulting mixture was ground/dispersed by wet grinding so that the average size of the dispersed particles became 0.3 μm. Thereafter, a zinc oxide having an average particle size of 0.5 μm and a dispersant having a content of 0.5% by weight of zinc oxide were added, and the resulting mixture was wet-milled so that the final size of the dispersed particles became 0.2 μm. The dispersing agent used herein is a polyacrylic acid amine salt. After the formation of the final zinc oxide-based slurry mixture, 1.0% by weight of polyvinyl acetate (PVA) and 0.5% by weight of polyethylene glycol (PEG) were added as a binder. Milling is performed again to produce a uniform slurry. Thereafter, the slurry was granulated as a powder by a spray drying method, and the granulated powder was compressed using an axial press followed by cold isostatic pressing.

In sequence, the resulting agglomerates were sintered at 1550 ° C for 15 hours in an air or oxygen atmosphere. After the end of the sintering, the electric resistance of the sintered product was 5.0×10 ^-3 Ω∙cm, and the sintered density was 5.67 g/cm ³ . The gallium oxide assembly system dispersed in the zinc oxide of the produced sintered body was detected by an electron probe micro-analyzer (EPMA) analysis, and the results are shown in Fig. 1. Referring to Fig. 1, it can be understood that all of the gallium oxide particles dispersed in the zinc oxide matrix are uniformly distributed in a range of 1 μm or less.

Example 2

The sinter made according to Example 1 was bonded to a backing plate made of Cu, and sputtering was performed using the resulting structure. The sputtering conditions are controlled such that the basic pressure of the chamber is 1 x 10 ^-6 torr and the working pressure is 0.5 Pa. The deposition was initiated by generating a plasma discharge at 100 ° C in a pure Ar environment. Here, the target size is 565 mm X 690 mm and the induced power is DC 10 kW. The gallium-doped zinc oxide film formed was deposited to a thickness of 30 nm on the substrate. The substrate on which the thin film is deposited is a glass substrate which previously contains a piece of non-alkaline glass and an indium gallium zinc oxide (IGZO) layer formed on the glass. The sample (a) was prepared by depositing Cu or an electrode material on a gallium-doped zinc oxide (GZO) film deposited on the IGZO layer to a thickness of 30 nm, wherein the sample (b) was not deposited with GZO. The film was prepared by depositing Cu on the IGZO layer. A secondary ion mass spectrometer (SIMS) was performed to analyze whether Cu diffused into the IGZO layer, and the results were presented in Figures 2A and 2B. Referring to Fig. 2A, it can be found that Cu diffusion is suppressed by a gallium-doped zinc oxide (GZO) film. In contrast, referring to FIG. 2B, it can be found that the Cu component diffuses into the IGZO layer when Cu is deposited on the pure IGZO layer.

Further, regarding the thin film transistor structure, in order to detect whether the barrier layer deposited using the zinc oxide-based sputtering target according to the present invention acts as a protective coating for Cu when the SiO _x layer is deposited on the source electrode and the gate electrode For the layer, the sample (c) and the sample (d) are prepared using a substrate comprising a piece of non-alkaline glass and a Cu layer deposited on the glass. A sample (c) is prepared by depositing a gallium oxide-doped zinc oxide (GZO) film on a substrate using a zinc oxide-based sputtering target according to the present invention, and then by chemical vapor deposition (CVD). A SiO _x film is deposited, and the sample (d) is prepared by depositing an indium oxide-doped zinc oxide (IZO) film on a substrate and then depositing a SiO _x film by CVD. The sample (c) and the sample (d) were etched using a Cu etching solution. A transmission electron microscopy (TEM) was performed to analyze whether or not there was residual residue, and the results were shown in FIGS. 3A and 3B. Referring to Figs. 3A and 3B, it was found that the residual system remained only in the comparative example of Fig. 3B.

4A, 4B, 5A, and 5B are diagrams showing the results of observing whether or not CuO _{x is} formed when the material of the barrier layer on the Cu electrode is changed, wherein FIG. 4A and FIG. 4B are drawn. The state in which the SiO _x film is deposited on the barrier layer after depositing the barrier layer on the Cu electrode using the zinc oxide-based sputtering target according to the present invention, and FIGS. 5A and 5B illustrate the use of the Cu-Mn standard. After the target deposition barrier layer is deposited on the Cu electrode, the SiO _x film is deposited on the barrier layer. Compared with the 4A and 4B, there is no change before and after the deposition of the SiO _x film. In contrast, compared to Figures 5A and 5B, it can be seen that the device varies before and after deposition of the SiO _x film. In other words, when the gallium oxide doped zinc oxide-based barrier layer is formed on the Cu electrode using the zinc oxide-based sputtering target according to the present invention, even if a SiO _x film is formed, between the Cu electrode and the SiO _x film The reaction is reduced by blocking the layer. In contrast, when the Cu-Mn barrier layer is formed on the Cu electrode, the barrier layer does not contribute to reducing the reaction between the Cu electrode and the SiO _x film, so that CuO _x is due to the relationship between Cu and SiO _x Formed by reaction. This in turn deteriorates the contact characteristics between the Cu electrode and the SiO _x film, and thus also degrades the film transistor characteristics.

 The above description of certain exemplary embodiments of the invention has been presented with respect to the drawings. It is not intended to be exhaustive or to limit the scope of the invention.

 Therefore, it is intended that the scope of the invention is not to be

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Claims (21)

A zinc oxide-based sputtering target comprising:
A sinter comprising zinc oxide doped with gallium oxide having a content of 10 to 50 weight percent of the sinter; and a backing plate bonded to a back surface of the sinter to support the sinter. The zinc oxide-based sputtering target according to claim 1, wherein the zinc oxide-based sputtering target has a resistance of 100 · cm or less.  The zinc oxide-based sputtering target according to claim 2, wherein the zinc oxide-based sputtering target is suitable for continuous-current sputtering. A zinc oxide-based sputtering target according to claim 3, wherein the power intensity applied during the DC sputtering is between 0.1 and 8 W/cm ² . The zinc oxide-based sputtering target according to claim 1, wherein the zinc oxide-based sputtering target has a density of 5.3 g/cm ³ or more.  A zinc oxide-based sputtering target according to claim 1, wherein one of the aggregates of gallium oxide is distributed in the sintered body in a size of 1 μm or less.  The zinc oxide-based sputtering target according to claim 1, wherein the sintered body comprises at least one selected from the group consisting of a Group III element and a Group IV element.  A method of manufacturing a thin film transistor comprising an electrode and an oxidized semiconductor layer, the method comprising depositing a barrier layer between the electrode and the oxidized semiconductor layer using a zinc oxide-based sputtering target as described in claim 1 .  The method of claim 8, wherein the barrier layer has a crystal size of from 10 to 5000 Å.  The method of claim 8, wherein the barrier layer is deposited to a thickness of between 30 and 50 nm. The method of claim 10, wherein the resistance of the barrier layer is between 100 and 1×10 ⁻⁴ Ω·cm.  The method of claim 8, wherein the electrode comprises Cu. A method of making a zinc oxide-based sputtering target, comprising:
Preparing a slurry by adding gallium oxide to zinc oxide, the content of gallium oxide being between 10 and 50 weight percent of the slurry;
Drying the slurry to form a granular powder;
The granulated powder is shaped into a mass; and the agglomerate is sintered as a sinter. The method of claim 13, wherein preparing the slurry comprises:
a first dispersing step of mixing a solution of gallium oxide with one of distilled water and a first dispersing agent, followed by wet grinding; and a second dispersing step by mixing a suspension formed by the first dispersing step with a The second dispersant and zinc oxide are then wet milled to form the slurry.  The method of claim 14, wherein the first dispersing step comprises performing wet milling such that the gallium oxide has an average particle size of from 0.2 to 0.6 μm.  The method of claim 14, wherein the first dispersing step comprises adding the first dispersing agent in an amount of from 0.1 to 2% by weight of the gallium oxide.  The method of claim 14, wherein the second dispersing step comprises adding the second dispersing agent in an amount of from 0.3 to 2.5 weight percent of the zinc oxide.  The method of claim 14, wherein the second dispersing step is controlled such that the slurry has an average particle size of from 0.1 to 0.5 μm.  The method of claim 14, wherein preparing the slurry further comprises adding a binder to the slurry.  The method of claim 13, wherein sintering the agglomerate comprises sintering the agglomerate in an air or oxygen atmosphere at a temperature between 1400 and 1600 °C.  A thin film transistor comprising an electrode, a barrier layer and an oxidized semiconductor layer, wherein the barrier layer is disposed between the electrode and the oxidized semiconductor layer, and comprises zinc oxide doped with gallium oxide, and the content of gallium oxide is between the blocking 5 to 40 weight percent of the layer.