Molybdenum oxide target material and preparation method and application thereof

Abstract

The invention discloses a molybdenum oxide target material and a preparation method and application thereof. Relates to the field of target preparation. The microstructure of the molybdenum oxide target material comprises a Mo phase, a MoO2 phase, a Nb2O5 phase, a calcium-based compound derivative phase and a magnesium-based compound derivative phase, the M4 phase is distributed at the grain boundary of Nb2O5 and MoO2, and the calcium-based compound derivative phase is distributed inside MoO2 grains. According to the microstructure of the molybdenum oxide target material, through the synergistic effect of the Mo phase (M1), the MoO2 phase (M2), the Nb2O5 phase (M3) and the calcium-based and magnesium-based derivative phases (M4 / M5), the comprehensive performance that the target material is high in density (the relative density is larger than or equal to 98.5%) and low in resistivity (smaller than or equal to 3.53 * 10 <-3 > omega.cm) and the sputtering film is high in transmittance (larger than or equal to 87%) and low in reflectivity (smaller than or equal to 45%) is achieved.

Description

Technical Field

[0001] This invention relates to the field of target preparation technology, and in particular to a molybdenum oxide target, its preparation method and application. Background Technology

[0002] In the field of electronic display devices, thin-film transistor liquid crystal displays (TFT-LCDs) have become the most widely used and industrialized display technology due to their advantages such as fast response speed, wide viewing angle, and high integration. The core structure of a TFT-LCD device includes components such as thin-film transistors (TFTs), gate electrodes, diffusion barrier layers, glass substrates, and polarizers. Among them, the diffusion barrier layer, as a key functional layer for optimizing photoelectric performance, not only corrects the uniformity of light in the backlight module, but also improves the visual presentation effect by preventing the reflection of external incident light and allowing internal light to pass through. This solves the problems of severe reflection in strong light environments and the suppression of displayed content by ambient light caused by the inability of LCDs to emit light themselves. As the requirements for high contrast and low reflectivity in display technology continue to increase, the development of diffusion barrier layer materials with excellent optical control performance has become crucial. Molybdenum oxide targets, as the core raw material for preparing this type of functional thin film, directly determine the optical, electrical, and mechanical properties of the film. Molybdenum oxide (MoO3) is a metal oxide with a layered orthorhombic crystal structure. It consists of (MoO6) octahedrons stacked in layers by sharing corners and edges, with the layers bonded by van der Waals forces. This structure endows it with excellent ion intercalation capabilities and optical modulation properties, making it promising for applications in photochromism, electrochromism, gas sensing, and display devices. In TFT-LCD devices, after preparing thin films from molybdenum oxide targets using techniques such as magnetron sputtering, its high refractive index and wide bandgap characteristics can be utilized to regulate light transmission and reflection, reducing ambient light interference. Simultaneously, optimizing the film's microstructure improves transmittance and mechanical stability, thereby enhancing the display panel's adaptability to strong light and visual comfort.

[0003] In existing technologies, the preparation methods for molybdenum oxide targets mainly include powder metallurgy, hot pressing and sintering, hot isostatic pressing, and reactive magnetron sputtering. Among these, powder metallurgy is currently the mainstream process for industrial production. The specific process involves using molybdenum concentrate as raw material, preparing ammonium molybdate via ammonia leaching, then calcining it to obtain molybdenum trioxide powder (purity up to 99.95%). The powder is then ball-milled, shaped, and sintered to obtain the target blank. In addition, reactive magnetron sputtering uses a high-purity metallic molybdenum target as the sputtering source. In an oxygen atmosphere, by controlling parameters such as vacuum and gas flow rate, molybdenum atoms react with oxygen atoms to generate a molybdenum oxide film. This method is widely used in laboratory and small-scale preparations. In terms of applications, thin films prepared from molybdenum oxide targets have been attempted for use as diffusion barrier layers and anti-reflective coatings in TFT-LCDs. Optical performance is optimized by adjusting the film thickness and crystal phase structure (such as orthorhombic or hexagonal phases). For example, MoO3 thin films prepared by DC magnetron sputtering can achieve visible light transmittance of over 80% and have an adjustable refractive index within the range of 2.0-2.5, effectively suppressing ambient light reflection and improving screen contrast. Meanwhile, molybdenum oxide targets are also used to prepare highly active electrode materials in fields such as thin-film solar cells and supercapacitors, exhibiting excellent electrochemical performance.

[0004] However, existing technologies for preparing and applying molybdenum oxide targets still have significant shortcomings, making it difficult to meet the stringent performance requirements of high-end TFT-LCDs. Firstly, regarding target preparation processes, traditional powder metallurgy methods suffer from the following problems: Firstly, insufficient powder purity; during the calcination of ammonium molybdate, alkali metal impurities such as sodium and potassium (typically >50 ppm) are easily introduced, leading to pinholes and defects in the sputtered film. Secondly, poor sintering density; hot pressing at temperatures above 600℃ easily causes MoO3 volatilization, and while hot isostatic pressing can improve density, incomplete vacuuming of the cladding can cause internal porosity, affecting the uniformity of the sputtering rate. Existing oxygen supplementation processes are carried out in an air atmosphere; however, because the target is already sintered and dense, oxygen is difficult to diffuse into the interior, leading to differences in oxygen content inside and outside the target, and consequently causing fluctuations in film composition. Secondly, in the preparation of molybdenum oxide films using reactive magnetron sputtering, the use of metallic molybdenum targets as raw materials is prone to "target poisoning"—oxygen reacts with the surface of the molybdenum target to form an insulating oxide layer, leading to abnormal discharge and a decrease in deposition rate during sputtering. Furthermore, the film composition is significantly affected by oxygen flow rate, making it difficult to accurately control the stoichiometry (when the Mo / O atomic ratio deviates from the theoretical value of 1:3, the film transmittance decreases by up to 15%). In addition, existing molybdenum oxide targets suffer from insufficient microstructural uniformity, easily generating hard agglomerates during powder ball milling, resulting in uneven target grain size distribution and film thickness deviations exceeding ±5% during sputtering, failing to meet the uniformity requirements of large-size LCD panels. At the application level, existing molybdenum oxide films have poor mechanical properties and low adhesion to glass substrates, easily peeling off under high temperature and humidity environments. Moreover, long-term use leads to transmittance decay due to photochromic effects, severely impacting the lifespan of LCD devices. Simultaneously, the high-end molybdenum oxide target market has long been monopolized by foreign companies, causing domestic LCD panel manufacturers to rely on imports, resulting in persistently high costs.

[0005] In summary, existing methods for preparing molybdenum oxide targets have significant shortcomings in terms of purity control, density improvement, microstructure uniformity, and stability in large-scale production. The thin films prepared by these methods are insufficient to meet the requirements of high-end TFT-LCDs for low reflectivity, high transmittance, and aging resistance in terms of optical performance, mechanical stability, and long-term reliability.

[0006] Therefore, there is an urgent need to develop a high-purity, high-density, and uniformly microstructured molybdenum oxide target and its low-cost preparation method, which is of great significance for breaking through foreign technological monopolies and improving the strong light adaptability and market competitiveness of LCD display devices. Summary of the Invention

[0007] The purpose of this invention is to develop a high-purity, high-density, and uniformly microstructured molybdenum oxide target and its low-cost preparation method.

[0008] The first aspect of the present invention is: A molybdenum oxide target material is provided.

[0009] The second aspect of the present invention is: A method for preparing molybdenum oxide target material is provided.

[0010] The third aspect of the present invention is: Application of the molybdenum oxide target.

[0011] Specifically, the technical solution adopted according to the first aspect of the present invention is as follows: A molybdenum oxide target material, wherein the microstructure of the molybdenum oxide target material includes a Mo phase, a MoO2 phase, a Nb2O5 phase, as well as a calcium-based compound-derived phase and a magnesium-based compound-derived phase; The magnesium-based compound-derived phase is distributed at the grain boundaries of Nb2O5 and MoO2, while the calcium-based compound-derived phase is distributed inside the MoO2 grains.

[0012] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects: The microstructure of the molybdenum oxide target material of this invention achieves high density (relative density ≥ 98.5%) and low resistivity (≤ 3.53 × 10⁻⁶) through the synergistic effect of the Mo phase (named M1), MoO₂ phase (named M2), Nb₂O₅ phase (named M3), and calcium-based and magnesium-based compound-derived phases (named M4 and M5, respectively). -3 It possesses the combined properties of high transmittance (≥87%) and low reflectance (≤45%) of sputtered thin films (Ω·cm).

[0013] In this process, the Mo phase (M1) serves as a supporting framework, enhancing the bending strength of the target material. Simultaneously, it reacts with O2 in the sputtering chamber to generate molybdenum oxide, replenishing the active components in the film. The MoO2 phase (M2), as the core functional phase, ensures the low reflectivity of the film through its inherent optical properties, forming optical complementarity with the Nb2O5 phase (M3). The wide bandgap of Nb2O5 ensures high transmittance in the visible light region. The calcium-based compound-derived phase (M5), generated by the reaction of calcium-based compounds and MoO2, fills the interior of the MoO2 grains, suppressing its high-temperature volatilization. The magnesium-based compound-derived phase (M4), generated by the reaction of Nb2O5 and magnesium-based compounds, is distributed at the grain boundaries between Nb2O5 and MoO2. Together, they reduce porosity, increasing the density of the target material. The low resistivity characteristic stems from the conductive network and dense structure of the Mo phase promoting electron transport.

[0014] This multi-phase synergistic microstructure enables the molybdenum oxide thin film formed by target sputtering to act as a diffusion barrier layer in LCD devices. Through multiple reflections at the upper and lower interfaces of the film, it can offset the intensity of ambient light. At the same time, the high transmittance ensures a low internal light loss rate, ultimately solving the technical problem of the displayed content being suppressed by ambient light under strong light.

[0015] According to one embodiment of the present invention, the molybdenum oxide target material comprises, by mass percentage: Mo content ranges from 4.0% to 9.5%; MoO2 content is 66.58%-70.95%; Nb2O5 content is 21.5%-23.6%.

[0016] Increasing the Mo content appropriately can improve the strength of the target material (the bending strength of the target material of this invention is ≥28.8MPa), and optimizing the ratio of MoO2 to Nb2O5 can control the optical properties of the thin film.

[0017] According to one embodiment of the present invention, the target material further comprises CaCO3 and MgO, wherein the content of CaCO3 is 0.5%-1.0% and the content of MgO is 1.1%-2.5% by mass percentage.

[0018] According to one embodiment of the present invention, the calcium-based compound-derived phase is generated by reacting CaCO3 with MoO2; the magnesium-based compound-derived phase is generated by reacting Nb2O5 with MgO.

[0019] According to one embodiment of the present invention, the relative density of the target material is ≥98.5%.

[0020] According to one embodiment of the present invention, the resistivity of the target material is ≤3.53×10⁻⁶. -3 Ω·cm.

[0021] Specifically, the technical solution adopted according to the second aspect of the present invention is as follows: A method for preparing the molybdenum oxide target includes the following steps: S1: Mo, MoO2, Nb2O5, calcium-based compounds and magnesium-based compounds are mixed and then ball-milled with water to obtain a mixed slurry; S2: Spray granulation of the mixed slurry to obtain composite powder; S3: The composite powder is isostatically pressed to obtain a green blank; S4: Sinter the green blank to obtain the target material.

[0022] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects: This invention achieves high density and uniform microstructure of target material through a process of "ball milling-granulation-isostatic pressing-sintering". Ball milling ensures uniform mixing of components, spray granulation controls powder particle size, and isostatic pressing improves the density of green body.

[0023] According to one embodiment of the present invention, in step S1, the ball milling time is 10-14 hours. Preferably, the ball milling time is 10-12 hours.

[0024] According to one embodiment of the present invention, in step S1, the ball-to-material ratio during ball milling is 5-10:1. The present invention optimizes ball milling parameters to ensure uniform powder mixing and fine powder refinement.

[0025] According to one embodiment of the present invention, in step S2, the inlet air temperature of the spray granulation is 180-200°C.

[0026] According to one embodiment of the present invention, in step S2, the inlet air temperature of the spray granulation is 190-200°C.

[0027] According to one embodiment of the present invention, in step S2, the outlet air temperature of the spray granulation is 100-200°C.

[0028] According to one embodiment of the present invention, in step S2, the outlet air temperature of the spray granulation is 110-200℃.

[0029] According to one embodiment of the present invention, in step S2, the rotational speed of the atomizer used for spray granulation is 18000-22000 r / min. Preferably, in step S2, the rotational speed of the atomizer used for spray granulation is 20000-22000 r / min.

[0030] According to one embodiment of the present invention, in step S3, the isostatic pressing is wet cold isostatic pressing.

[0031] According to one embodiment of the present invention, in step S3, the molding pressure of the isostatic pressing is 200-250 MPa.

[0032] According to one embodiment of the present invention, in step S3, the holding time of the isostatic pressing is 5-15 minutes.

[0033] According to one embodiment of the present invention, in step S4, the sintering temperature is 1400-1550℃.

[0034] According to one embodiment of the present invention, in step S4, the sintering temperature is 1450-1550℃.

[0035] According to one embodiment of the present invention, in step S4, the heating rate of the sintering is 2-4°C / min. Preferably, the heating rate of the sintering is 2-3°C / min.

[0036] According to one embodiment of the present invention, in step S4, the holding time for sintering is 8-12 hours.

[0037] According to one embodiment of the present invention, in step S4, when the ambient temperature reaches the sintering temperature during sintering, nitrogen gas is introduced. Nitrogen gas acts as a protective gas to prevent molybdenum dioxide from contacting oxygen to form molybdenum trioxide. Molybdenum trioxide has a low melting point and boiling point (melting point 795°C, boiling point 1155°C), and it boils at high temperatures, making sintering impossible.

[0038] According to one embodiment of the present invention, in step S4, the nitrogen flow rate is 20-40 L / min. Preferably, the nitrogen flow rate is 25-40 L / min.

[0039] In another aspect, the present invention provides an LCD display device comprising a molybdenum oxide target as described in the first aspect embodiment. Since this application employs all the technical solutions of the aforementioned molybdenum oxide target, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0040] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the discovery. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 The flowchart shows the process of further preparing the target material prepared in Examples 1-5 into a TFT-LCD thin film structure, and the low-reflection mechanism diagram of the thin film structure.

[0042] Figure 2 The images show the microstructure and morphology of the targets prepared in Examples 1-5. Detailed Implementation

[0043] The terms "preferred," "more preferred," etc., used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0044] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present invention.

[0046] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0047] The following examples and comparative examples all used molybdenum oxide targets prepared by the following methods: each component was weighed according to the mass ratio in Table 1, and sintering was performed according to the parameters in Table 1; the specific steps are as follows: S1, Mo, MoO2, Nb2O5, CaCO3 and MgO are mixed to obtain a mixed powder, and deionized water of the same mass as the mixed powder is added and ball-milled for 12 hours to obtain a mixed slurry; S2, the mixed slurry is spray-granulated to obtain composite powder. During the spray granulation process, the atomizer speed is 20000 r / min, the inlet air temperature of the spray drying tower is 190℃, and the outlet air temperature is 110℃. S3, the composite powder is placed into a rigid mold and subjected to wet isostatic pressing at a pressure of 220 MPa to obtain a green blank; S4. The green blank is placed in a sintering furnace for sintering. Nitrogen gas is introduced during the sintering process. The heating rate of sintering is 2 ℃ / min, the sintering temperature is 1430-1480 ℃, the sintering holding time is 10 h, and the nitrogen gas flow rate is 0-40 L / min to obtain the target material semi-finished product.

[0048] S5. The sintered and cooled target material semi-finished product is machined and surface polished to obtain the target material finished product. The polishing wheel has a mesh size of 800.

[0049] Table 1

[0050] *In the preparation of molybdenum oxide target material in Comparative Example 1, oxygen was introduced instead of nitrogen during the sintering process in step S4.

[0051] Both the examples and comparative examples were prepared using the following method to prepare molybdenum oxide thin films (TFT-LCD thin films), as shown in the flowchart below. Figure 1 As shown: Molybdenum oxide targets prepared in the examples and comparative examples were ground and cleaned to remove impurities and oxide layers. The targets were then installed into the magnetron sputtering cavity. Simultaneously, glass was used as the deposition substrate, and it was ultrasonically cleaned for 15 minutes each with acetone and ethanol to remove surface oil and contaminants. After cleaning, the substrates were dried in an oven for later use. Subsequently, the sputtering cavity was closed and the vacuum pump was started to evacuate the vacuum chamber to a base vacuum of 5 × 10⁻⁶. -4 Pa; then, a mixture of Ar and O2 gas (volume ratio 4:1, total flow rate 20 sccm) was introduced into the cavity, the working gas pressure was adjusted to 0.5 Pa, and the RF power supply was set to 150 W to heat the substrate to 200°C. After all parameters stabilized, the sputtering program was started and sputtered continuously for 30 minutes, finally depositing a molybdenum oxide thin film on the surface of the glass substrate.

[0052] The TFT-LCD device was fabricated using the following method, and the fabrication flowchart is shown below. Figure 1 As shown: Using the molybdenum oxide thin film prepared above as a diffusion barrier layer, a gate electrode and a thin film transistor are sequentially assembled on one side of the diffusion barrier layer, and a glass and a polarizer are sequentially assembled on the other side of the diffusion barrier layer to obtain a TFT-LCD device.

[0053] Performance testing: The density, grain size, resistivity, transmittance, and reflectance of the molybdenum oxide target material of the examples and comparative examples were tested, and the test results are shown in Table 2.

[0054] The density test adopts Archimedes' displacement method. Specifically, the actual density of the target material is determined by displacement method, and the relative density is the ratio of the measured actual density to the theoretical density. Grain size observation requires a sample preparation and microscopic observation process: First, the sample is cut using wire cutting, and then polished step by step using wet sandpaper ranging from 500 grit to 7000 grit. To avoid residual abrasive particles affecting the surface gloss, wet polishing is required when polishing with 3000 grit and higher grit sandpaper. During each adjacent grit polishing process, the sample must be rotated 90° to ensure that the new scratches generated by each polishing completely cover the previous scratches. After wet polishing with 7000 grit sandpaper until there are no obvious scratches on the surface, mechanical polishing is performed using a diamond polishing spray with a particle size of 0.5μm until the sample surface reaches a mirror finish. Since the target sample does not require corrosion treatment, it can be directly observed using an optical microscope to analyze its microstructure and determine the grain size.

[0055] Table 2

[0056] From Table 2, we can see that: (1) Analysis of Examples 1-5 shows that as the Mo content increases, the resistivity and flexural strength of the target material increase simultaneously. This is mainly because the resistivity of the other oxides in the composition is higher than that of Mo. The increase of low resistivity components will inevitably improve the overall conductivity of the target material. During the sintering process, Mo does not react with other components and still exists in the form of metal, which can play a supporting role. Therefore, the composition and strength are positively correlated.

[0057] (2) Analysis of Comparative Example 1 shows that during sintering, nitrogen was not introduced (the addition of nitrogen can inhibit the volatilization of MoO2), but oxygen was introduced instead (molybdenum dioxide will generate molybdenum trioxide when it comes into contact with oxygen, and molybdenum trioxide has a low melting point and boiling point (melting point 795℃, boiling point 1155℃), and it cannot be sintered at high temperature), resulting in insufficient density of the sintered product.

[0058] (3) Analysis of Example 2 and Comparative Example 4 shows that the addition of CaCO3 significantly increases the density of the target material, indicating that CaCO3 plays a significant role in densifying the target material. This is mainly because MoO2 and CaCO3 in the composition react to form CaMoO4, and the reaction formula is CaCO3 + MoO2 = CaMoO4 + CO2↑. The formed CaMoO4 can fill the grain boundaries and play a densifying role.

[0059] (4) Analysis of Example 3 and Comparative Example 2 shows that the addition of MgO significantly increases the density of the target material, indicating that MgO also plays a significant role in the densification of the target material. This is mainly because Nb2O5 reacts with MgO to form MgNb2O6, which fills the grain boundaries to ensure a high density of the material. The reaction formula is Nb2O5 + MgO = MgNb2O6.

[0060] (5) Analysis of Example 3 and Comparative Example 3 shows that the introduction of nitrogen can increase the density, mainly because the addition of nitrogen can suppress the volatilization of MoO2.

[0061] Figure 1 Flowcharts and diagrams illustrating the low-reflection mechanism of TFT-LCD thin film structures prepared using the targets in Examples 1-5 are provided. Figure 1 (a) is a schematic diagram of a TFT-LCD structure. Figure 1 (b) is a magnified view of the position of the thin film in Figure (a). Figure 1 (c) is a diagram of the low reflection mechanism.

[0062] from Figure 1As can be seen from (a), the TFT-LCD device is composed of a thin film structure. From right to left, the film structure consists of a thin film transistor (TFT), a gate electrode, a diffusion barrier layer, glass, and a polarizing film. The molybdenum oxide film serves as a diffusion barrier layer to achieve a low-reflection effect of the device.

[0063] from Figure 1 As shown in Figure (b), in a TFT-LCD device, external light enters from the right side, passes through the polarizer and glass, and is reflected when it passes through the diffusion barrier layer. This is also the reason why the displayed content is suppressed by ambient light.

[0064] from Figure 1 As shown in Figure (c), compared to traditional barrier layer materials (left figure), when using molybdenum oxide (MoOx) film as a diffusion barrier layer (right figure), after external light enters, the light will undergo multiple reflections at the film interface on the left and right sides of the molybdenum oxide (MoOx) film. The intensity of the light reflected from the screen is much lower than that of the incident light, thus achieving a low reflection effect.

[0065] Figure 2 The images show the microstructure of the targets prepared in Examples 1-5.

[0066] from Figure 2 Analysis reveals five types of target microstructures, M1-M5. M1 is Mo, primarily used to enhance target strength and react with O2 in the sputtering chamber during sputtering to form molybdenum oxide, ensuring low reflectivity. M2 is MoO2, ensuring low reflectivity of the thin film. M3 is Nb2O5, ensuring high transmittance. M4 is an intermediate phase formed during the sintering of Nb2O5 and MgO, located between Nb2O5 and MoO2, filling the grain boundaries and increasing the density of the sintered body. M5 is an intermediate phase formed during the reaction of MoO2 and CaCO3, located inside MoO2, used to reduce the high-temperature volatilization of MoO2.

[0067] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A molybdenum oxide target material, characterized in that: The microstructure of molybdenum oxide targets includes Mo phase, MoO2 phase, Nb2O5 phase, as well as calcium-based compound-derived phase and magnesium-based compound-derived phase; The magnesium-based compound-derived phase is distributed at the grain boundaries of Nb2O5 and MoO2, while the calcium-based compound-derived phase is distributed inside the MoO2 grains.

2. The molybdenum oxide target material according to claim 1, characterized in that: The components of the molybdenum oxide target, by mass percentage, include: Mo content ranges from 4.0% to 9.5%; MoO2 content is 66.58%-70.95%; Nb2O5 content is 21.5%-23.6%.

3. The molybdenum oxide target material according to claim 2, characterized in that: The target material also contains CaCO3 and MgO, with CaCO3 content of 0.5%-1.0% and MgO content of 1.1%-2.5% by mass percentage.

4. The molybdenum oxide target material according to claim 3, characterized in that: The calcium-based compound-derived phase is generated by the reaction of CaCO3 and MoO2; the magnesium-based compound-derived phase is generated by the reaction of Nb2O5 and MgO.

5. A method for preparing a molybdenum oxide target as described in any one of claims 1 to 3, characterized in that: Includes the following steps: S1: Mo, MoO2, Nb2O5, calcium-based compounds and magnesium-based compounds are mixed and then ball-milled with water to obtain a mixed slurry; S2: Spray granulation of the mixed slurry to obtain composite powder; S3: The composite powder is isostatically pressed to obtain a green blank; S4: Sinter the green blank to obtain the target material.

6. The method according to claim 5, characterized in that: In step S1, the ball milling time is 10-14 hours.

7. The method according to claim 5, characterized in that: In step S4, the sintering temperature is 1400-1550℃.

8. The method according to claim 5, characterized in that: In step S4, when the ambient temperature reaches the sintering temperature during sintering, nitrogen gas is introduced.

9. The method according to claim 5, characterized in that: In step S4, the nitrogen flow rate is 20-40 L / min.

10. An LCD display device, characterized in that: Including a molybdenum oxide target as described in any one of claims 1 to 3.

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