Preparation method for fluorine-doped tin oxide target material

Abstract

The present application relates to the field of materials, and in particular to a preparation method for a fluorine-doped tin oxide target material. A powder mixture of raw materials is press-formed and is then sintered. The powder mixture comprises 70 wt.%-99.8 wt.% of SnO2, 0.1wt.%-10 wt.% of metal fluoride, 0 wt.%-10 wt.% of metal oxide, and 0 wt.%-10 wt.% of sintering aid. The melting point of the metal fluoride is greater than 800°C. According to the preparation method for the fluorine-doped tin oxide target material provided by the present application, the metal fluoride having a high melting point (greater than 800°C) is used for replacing stannous fluoride to serve as a fluorine source of a fluorine-doped tin oxide target material, thereby fundamentally solving the problem of metal fluoride decomposition in the high-temperature sintering process of the target material, improving the control accuracy of components of the target material, and effectively improving the photoelectric performance of a fluorine-doped tin oxide film.

Description

Preparation method of fluorine-doped tin oxide target Technical Field

[0001] The present application relates to the field of materials, and in particular to a method for preparing a fluorine-doped tin oxide target. Background Art

[0002] In2O3-based transparent conductive materials are currently the most commonly used transparent conductive oxides (TCOs) in the industry. However, due to the rarity of indium metal and the instability of In2O3 in reducing atmospheres and relatively high humidity air environments, tin oxide-based TCO films have been developed and utilized in recent years as alternatives to indium oxide-based TCO films. Among them, the most popular fluorine-doped tin oxide (FTO) film is widely used in technical fields such as solar cells, touch screen liquid crystal displays, thin film transistors, organic and inorganic semiconductor lasers, and thermal insulation and energy-saving glass.

[0003] Currently, the main methods for preparing FTO films include sol-gel hydrothermal method, spray pyrolysis method, chemical vapor deposition method (CVD) and physical vapor deposition method (PVD). Among them, physical vapor deposition method (PVD), such as magnetron sputtering method (MS), reactive plasma deposition method (RPD), ion beam sputtering method (IS), etc., have been widely used due to their low cost, simple process, compatibility with low-temperature process, and easy operation, making them suitable for large-scale industrial production. The preparation of tin oxide-based transparent conductive oxide films using physical vapor deposition (PVD) has become a hot topic in industry research.

[0004] The target material commonly used in the physical vapor deposition (PVD) process for producing fluorine-doped tin oxide (FTO) thin films is a non-metallic target made by mixing tin oxide powder and stannous fluoride powder, pressing them, and then sintering them at high temperatures. However, further improving the optoelectronic properties of FTO films produced using this method is difficult.

[0005] Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a method for preparing a fluorine-doped tin oxide target.

[0007] The present application provides a method for preparing a fluorine-doped tin oxide target, comprising:

[0008] The powder mixture of the raw materials is pressed into shape and then sintered;

[0009] The powder mixture comprises: 70 wt.% to 99.9 wt.% SnO2, 0.1 wt.% to 10 wt.% metal fluoride; 0 wt.% to 10 wt.% metal oxide; 0 wt.% to 10 wt.% sintering aid;

[0010] The melting point of metal fluorides is greater than 800°C.

[0011] A method for preparing a fluorine-doped tin oxide target by high-temperature sintering of tin oxide powder and stannous fluoride powder, wherein the sintering temperature of the target is generally above 1200°C. However, the melting point of stannous fluoride is 215°C and the boiling point is 850°C, which is much lower than the sintering temperature. Therefore, during the long sintering process, stannous fluoride will decompose in large quantities, resulting in extremely low fluorine content in the target and it is difficult to accurately control it. This makes it difficult to further improve the photoelectric properties of the fluorine-doped tin oxide film. The preparation method of the fluorine-doped tin oxide target provided in the present application uses a metal fluoride with a high melting point (>800°C) instead of stannous fluoride as the fluorine source of the fluorine-doped tin oxide target, which fundamentally solves the problem of metal fluoride decomposition during the high-temperature sintering of the target, thereby improving the control accuracy of the target composition, and thus can effectively improve the photoelectric properties of the fluorine-doped tin oxide film.

[0012] In other embodiments of the present application, the metal ion radius of the metal fluoride is less than 120 pm.

[0013] In other embodiments of the present application, the metal fluoride includes at least one of alkali metal fluoride, alkaline earth metal fluoride, lanthanide metal fluoride, YF3, TiF3, MnF2, FeF3, CoF2, NiF2, CuF, ZnF2 or CdF2.

[0014] In other embodiments of the present application, the metal fluoride is preferably at least one of LiF, MgF2, ScF3, TiF3, CrF3, MnF2, FeF3, CoF2, NiF2, CuF2, ZnF2, InF3, YF3, LaF3 or NdF3.

[0015] In other embodiments of the present application, the metal oxide includes at least one of Ta2O5, Nb2O5, Nb2O4, Sb2O5, Sb2O3, MoO3, WO3, WO2, V2O5 or V2O3.

[0016] In other embodiments of the present application, the sum of the fluorine content in the metal fluoride and the metal ion content in the metal oxide is less than 10 mol%.

[0017] In other embodiments of the present application, the sintering aid includes at least one of ZnO, MnO, TiO2, Nb2O5, Co2O3, Sb2O5, Sb2O3, Li2O, CuO, Ca2O3, Fe2O3 or FeO.

[0018] In other embodiments of the present application, the particle size of the powder mixture is 20 nm-20 μm.

[0019] In other embodiments of the present application, sintering includes:

[0020] Heat the raw material powder mixture at 1000℃~1600℃ for 120min~3000min;

[0021] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0022] In other embodiments of the present application, the compression molding includes:

[0023] The powder mixture of the raw materials is placed in a mold and pressed at a pressure of 50 MPa to 800 MPa for 5 to 30 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0025] FIG1 is a schematic diagram of an embodiment of the present application providing an embodiment of the incorporation of metal cations less than 120 pm into a tin oxide lattice;

[0026] FIG2 shows a SEM image of the target material prepared in Example 1 of the present application;

[0027] FIG3 shows an SEM image of the target material prepared in Comparative Example 1;

[0028] FIG4 shows a SEM image of the target material prepared in Example 2 of the present application;

[0029] FIG5 shows a SEM image of the target material prepared in Example 3 of the present application;

[0030] FIG6 shows a SEM image of the target material prepared in Example 4 of the present application;

[0031] FIG7 shows a SEM image of the target material prepared in Example 6 of the present application;

[0032] FIG8 shows a SEM image of the target material prepared in Example 7 of the present application;

[0033] FIG9 shows a SEM image of the target material prepared in Example 8 of the present application;

[0034] FIG10 shows a SEM image of the target material prepared in Example 9 of the present application;

[0035] FIG11 shows a SEM image of the target material prepared in Example 10;

[0036] FIG12 shows an SEM image of the target material prepared in Example 11;

[0037] FIG13 shows a SEM image of the target material prepared in Example 12 of the present application;

[0038] FIG14 shows a comparison of transmittance spectra of the films of Example 4 and Comparative Example 1;

[0039] FIG15 shows a comparison of the absorptivity spectra of the films of Example 4 and Comparative Example 1;

[0040] FIG16 shows a comparison of transmittance spectra of the films of Example 8 and Comparative Example 1;

[0041] FIG17 shows a comparison of the absorptivity spectra of the films of Example 8 and Comparative Example 1;

[0042] FIG18 shows a comparison of transmittance spectra of the films of Example 12 and Comparative Example 1;

[0043] FIG19 shows a comparison of the absorbance spectra of the films of Example 12 and Comparative Example 1. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0047] In the description of the embodiments of the present application, it should be understood that the indicated orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of the application is conventionally placed when in use, or the orientation or position relationship conventionally understood by those skilled in the art. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0048] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0049] The method for preparing fluorine-doped tin oxide targets by high-temperature sintering of tin oxide powder and stannous fluoride powder generally requires sintering at temperatures above 1200°C. However, stannous fluoride has a melting point of 215°C and a boiling point of 850°C, far below the sintering temperature. Therefore, during the long sintering process, stannous fluoride decomposes significantly, resulting in extremely low fluorine content in the target, which is difficult to precisely control. Consequently, further improvements in the optoelectronic properties of fluorine-doped tin oxide films are difficult.

[0050] The present application provides a method for preparing a fluorine-doped tin oxide target, comprising:

[0051] sintering the powder mixture of raw materials;

[0052] The powder mixture comprises: 70 wt.% to 99.9 wt.% SnO2, 0.1 wt.% to 10 wt.% metal fluoride; 0 wt.% to 10 wt.% metal oxide; 0 wt.% to 10 wt.% sintering aid;

[0053] The melting point of metal fluorides is greater than 800°C.

[0054] The preparation method of the fluorine-doped tin oxide target provided in the present application uses a metal fluoride with a high melting point (>800°C) instead of stannous fluoride as the fluorine source of the fluorine-doped tin oxide target, which fundamentally solves the problem of metal fluoride decomposition during the high-temperature sintering process of the target, thereby improving the control accuracy of the target composition, and further effectively improving the photoelectric performance of the fluorine-doped tin oxide film.

[0055] Furthermore, current methods for preparing fluorine-doped tin oxide targets by high-temperature sintering of tin oxide powder and stannous fluoride powder typically employ hot isostatic pressing (HIP) with mechanical excitation or spark plasma sintering (SPS) with both mechanical and plasma excitation to accelerate the sintering process and reduce sintering time, in order to mitigate the problem of extensive decomposition of stannous fluoride. However, the equipment used in these HIP and SPS methods is very expensive, significantly increasing the difficulty of commercializing fluorine-doped tin oxide targets (FTO targets).

[0056] This application uses high melting point (>800℃) metal fluoride instead of stannous fluoride as the fluorine source of fluorine-doped tin oxide target, and for the first time realizes the preparation of dense anion and cation co-doped fluorine tin oxide target using normal pressure high temperature sintering method, which is beneficial to reduce the dependence on expensive hot isostatic pressing equipment or discharge plasma equipment, greatly reduces the cost of dense anion and cation co-doped fluorine tin oxide target, and is beneficial to the industrial application of fluorine-doped tin oxide target (FTO target).

[0057] Furthermore, the present invention uses a high-melting-point (>800°C) metal fluoride as the fluorine source for the fluorine-doped tin oxide target. This can simultaneously introduce metal ions into the target, inducing a refinement of the target's grain size and shape, and improving the target's density. Applying this to the physical vapor deposition (PVD) method for preparing fluorine-doped tin oxide (FTO) thin films can eliminate defect structures in the film, thereby improving the film's photoelectric properties, increasing the film's transmittance, reducing the film's absorption, increasing the film's carrier concentration, increasing the film's mobility, and reducing the film's resistivity.

[0058] Furthermore, in some embodiments of the present application, a method for preparing a fluorine-doped tin oxide target comprises:

[0059] Step S1: preparing a powder mixture of raw materials.

[0060] The raw material powder mixture is ground to a particle size of 20 nm to 20 μm.

[0061] Further optionally, the powder mixture of the raw materials is ground until the particle size of the powder mixture is 50 nm-10 μm.

[0062] Illustratively, the powder mixture of the raw materials is ground until the particle size of the powder mixture is 60 nm, 100 nm, 200 nm, 300 nm, 500 nm, 1 μm or 5 μm.

[0063] Further, in some embodiments of the present application, grinding includes:

[0064] After mixing all the raw materials, place them in a ball mill and add grinding balls;

[0065] Start the ball mill, set the speed to 100 rpm-800 rpm, grind for 3-20 minutes, then stop for 5-20 minutes;

[0066] Repeat the above steps 5-30 times.

[0067] Illustratively, in some embodiments of the present application, grinding includes: mixing the raw materials, placing them in a ball mill, and adding grinding balls; starting the ball mill, setting the speed to 500 rpm, grinding for 10 minutes and then stopping for 10 minutes; repeating the above steps 10 times.

[0068] Furthermore, in some embodiments of the present application, the ground powder mixture is dried.

[0069] Further, in some embodiments of the present application, drying comprises:

[0070] The ground powder mixture is dried at a drying temperature of 70° C. to 120° C. and a drying time of 50 min to 100 min.

[0071] Exemplarily, drying includes: drying the ground powder mixture at a drying temperature of 100° C. and a drying time of 60 minutes.

[0072] In other optional embodiments of the present application, the particle size of each raw material may be ground to 20 nm-20 μm before the raw materials are mixed.

[0073] Step S2: pressing the powder mixture of the raw materials obtained in step S1 into a mold.

[0074] In some embodiments of the present application, the above-mentioned pressing molding includes: placing the powder mixture of the raw materials in a mold, and pressing at a pressure of 50 MPa to 800 MPa for 5 minutes to 30 minutes.

[0075] Further optionally, in some embodiments of the present application, the above-mentioned pressing molding includes: placing the powder mixture of the raw materials in a mold, and pressing at a pressure of 51 MPa to 795 MPa for 6 minutes to 29 minutes.

[0076] Illustratively, in some embodiments of the present application, the compression molding includes:

[0077] The powder mixture of the raw materials is placed in a mold and pressed at 55 MPa, 60 MPa, 80 MPa, 100 MPa, 200 MPa, 500 MPa or 700 MPa for 8 min, 10 min, 15 min, 20 min or 25 min.

[0078] Step S3: sintering the powder mixture of the pressed raw materials obtained in step S2.

[0079] In some embodiments of the present application, the powder mixture includes: 70 wt.% to 99.9 wt.% SnO2, 0.1 wt.% to 10 wt.% metal fluoride; 0 wt.% to 10 wt.% metal oxide; and 0 wt.% to 10 wt.% sintering aid.

[0080] Further optionally, in some embodiments of the present application, the above-mentioned powder mixture includes: 71wt.% to 99.8wt.% SnO2, 0.1wt.% to 10wt.% metal fluoride; 0.1wt.% to 10wt.% metal oxide; and 0.1wt.% to 10wt.% sintering aid.

[0081] For example, in some embodiments of the present application, the powder mixture comprises: 99.9 wt.% SnO2, 0.1 wt.% metal fluoride; or, the powder mixture comprises: 99 wt.% SnO2, 0.5 wt.% metal fluoride, and 0.5 wt.% metal oxide. Alternatively, the powder mixture comprises: 99 wt.% SnO2, 0.5 wt.% metal fluoride, 0.25 wt.% metal oxide, and 0.25 wt.% sintering aid.

[0082] Furthermore, in some embodiments of the present application, the melting point of the above-mentioned metal fluoride is greater than 800°C.

[0083] The melting point of metal fluoride is greater than 800° C., which can effectively solve the problem of metal fluoride decomposition and promote the densification of the fluorine-doped tin oxide target, thereby obtaining a fluorine-doped tin oxide target with a denser structure.

[0084] Furthermore, in some embodiments of the present application, the metal ion radius of the metal fluoride is less than 120 pm.

[0085] Since the formation energy of interstitial tin (Sni) in SnO2 is very low, a large amount of Snni will be formed in the film under an oxygen-deficient environment. Further, these tetravalent interstitial atoms will be reduced to divalent atoms, causing lattice relaxation and forming Sn 2+ iV o Compound defects cause a sharp deterioration in the optical and electrical properties of the film.

[0086] 1 , in the embodiment of the present application, the use of metal cations less than 120 pm doped into the tin oxide target can reduce Sn i The amount of SnO2 can be eliminated by lattice relaxation and the defect structure can be reduced. 2+ i -V o Composite defects are beneficial to improving the optical and electrical properties of tin oxide-based films.

[0087] Furthermore, in some embodiments of the present application, when the amount of metal oxide added to the above-mentioned powder mixture is greater than 0 wt.%, the metal fluoride and metal oxide are co-doped with tin oxide, and the anions and cations (metal cations and fluoride ions) are co-doped, which can reduce the impurity ion doping concentration, reduce the fluorine doping amount, increase the optical transmittance of the film, reduce the optical absorption of the film, increase the carrier concentration of the fluorine-doped tin oxide film, increase the mobility of the film and reduce the resistivity of the film.

[0088] Furthermore, in some embodiments of the present application, when the amount of the sintering aid added to the above-mentioned powder mixture is greater than 0 wt.%, the sintering aid can synergize with the high melting point (>800°C) metal fluoride to further promote the densification of the fluorine-doped tin oxide target.

[0089] Furthermore, by adding more than 0 wt.% of sintering aid to the above powder mixture, the additional use of organic binder is avoided. Compared with conventional targets using binders, the fluorine-doped tin oxide target prepared by the method of the present application has higher purity and better density.

[0090] Furthermore, in some embodiments of the present application, the metal fluoride includes at least one of alkali metal fluoride, alkaline earth metal fluoride, lanthanide metal fluoride, YF3, TiF3, MnF2, FeF3, CoF2, NiF2, CuF, ZnF2 or CdF2.

[0091] Furthermore, in some embodiments of the present application, the above-mentioned alkali metal fluoride includes: lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride and cesium fluoride.

[0092] Furthermore, in some embodiments of the present application, the alkaline earth metal fluoride includes: calcium fluoride, magnesium fluoride, barium fluoride and strontium fluoride.

[0093] Furthermore, in some embodiments of the present application, the metal fluoride is preferably at least one of LiF, MgF2, ScF3, TiF3, CrF3, MnF2, FeF3, CoF2, NiF2, CuF2, ZnF2, InF3, YF3, LaF3 or NdF3.

[0094] Illustratively, in some embodiments of the present application, the metal fluoride in the aforementioned powder mixture is selected from any one of LiF, MgF2, ScF3, TiF3, CrF3, MnF2, FeF3, CoF2, NiF2, CuF2, ZnF2, InF3, YF3, LaF3 or NdF3; or the metal fluoride in the aforementioned powder mixture is selected from a mixture of LiF and MgF2; or the metal fluoride in the aforementioned powder mixture is selected from a mixture of ScF3, TiF3, CrF3, and MnF2; or the metal fluoride in the aforementioned powder mixture is selected from a mixture of YF3, LaF3, and NdF3.

[0095] The various raw materials in the above mixture can be mixed in any proportion.

[0096] Furthermore, in some embodiments of the present application, the metal oxide includes at least one of Ta2O5, Nb2O5, Nb2O4, Sb2O5, Sb2O3, MoO3, WO3, WO2, V2O5 or V2O3.

[0097] Illustratively, in some embodiments of the present application, the metal oxide in the aforementioned powder mixture is selected from any one of Ta2O5, Nb2O5, Nb2O4, Sb2O5, Sb2O3, MoO3, WO3, WO2, V2O5 or V2O3; or the metal oxide in the aforementioned powder mixture is selected from a mixture of Ta2O5 and Nb2O5; or the metal oxide in the aforementioned powder mixture is selected from a mixture of Nb2O4, Sb2O5, and Sb2O3; or the metal oxide in the aforementioned powder mixture is selected from a mixture of MoO3, WO3, WO2, V2O5 and V2O3.

[0098] The various raw materials in the above mixture can be mixed in any proportion.

[0099] Furthermore, in some embodiments of the present application, the sum of the fluorine content in the metal fluoride and the metal ion content in the metal oxide is less than 10 mol%.

[0100] Due to the limited solid solubility of fluorine in tin oxide, it is difficult to further increase the carrier concentration of fluorine-doped tin oxide (FTO) films. In addition, fluorine enters the tin oxide lattice to form a large number of impurity scattering centers, resulting in a decrease in carrier mobility. On the other hand, fluorine doping also causes strong impurity absorption, seriously affecting the light transmittance of tin oxide.

[0101] By limiting the sum of the fluorine content in the metal fluoride and the metal ion content in the metal oxide to less than 10 mol.%, when the metal oxide is co-doped with fluorine, an excellent solid solution phase can be formed, thereby reducing the impurity ion doping concentration, reducing the fluorine doping amount, increasing the optical transmittance of the film, reducing the optical absorption of the film, increasing the carrier concentration of the fluorine-doped tin oxide film, improving the mobility of the film and reducing the resistivity of the film.

[0102] Furthermore, in some embodiments of the present application, the sintering aid includes at least one of: ZnO, MnO, TiO2, Nb2O5, Co2O3, Sb2O5, Sb2O3, Li2O, CuO, Ca2O3, Fe2O3 or FeO.

[0103] Illustratively, in some embodiments of the present application, the sintering aid in the above-mentioned powder mixture is selected from: any one of ZnO, MnO, Sb2O3, Li2O, CuO, Ca2O3, Fe2O3 or FeO; or the sintering aid in the above-mentioned powder mixture is selected from a mixture of ZnO and MnO; or the sintering aid in the above-mentioned powder mixture is selected from a mixture of TiO2, Nb2O5, Co2O3, Sb2O5; or the sintering aid in the above-mentioned powder mixture is selected from a mixture of Sb2O3, Li2O, CuO, Ca2O3, Fe2O3 and FeO.

[0104] The various raw materials in the above mixture can be mixed in any proportion.

[0105] It should be noted that, in some embodiments of the present application, Nb2O5 can be used as a sintering aid for the sintering of fluorine-doped tin oxide targets, and can also be used as a doped metal oxide for the targets.

[0106] During high-temperature sintering, tin oxide uses non-densifying mass transfer mechanisms such as surface diffusion and evaporation-condensation to control material transport. These processes only promote pore coarsening and grain growth, but are difficult to densify. In the embodiment of the present application, a sintering aid is added to densify the tin oxide target.

[0107] Furthermore, in some embodiments of the present application, sintering includes:

[0108] Heat the raw material powder mixture at 1000℃~1600℃ for 120min~3000min;

[0109] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0110] Further optionally, in some embodiments of the present application, sintering includes:

[0111] Heat the raw material powder mixture at 1010℃~1590℃ for 125min~2900min;

[0112] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0113] Illustratively, in some embodiments of the present application, sintering includes:

[0114] The powder mixture of the raw materials is kept at 1100°C, 1200°C, 1300°C, 1400°C or 1500°C for 130min, 150min, 200min, 250min, 300min, 500min or 1000min; and then cooled to room temperature at a cooling rate of 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min.

[0115] The features and performance of the present invention are further described in detail below with reference to the embodiments:

[0116]

Preparation of fluorine-doped tin oxide target

[0117] A method for preparing a fluorine-doped tin oxide target is provided, which is prepared according to the following steps:

[0118] (1) Weigh SnO2, metal fluoride, metal oxide, and sintering aid according to a set ratio and mix to obtain a mixture.

[0119] (2) The mixture in step (1) is placed in a ball mill and grinding balls are added; the ball mill is started and the speed is set to 500 rpm, and the mixture is ground for 10 minutes and then stopped for 10 minutes; the above steps are repeated 10 times to obtain a powder mixture.

[0120] (3) drying the powder mixture obtained in step (2) at 100° C. for 2 h;

[0121] (4) The powder mixture dried in step (3) is placed in a mold, and the mold is pressed; the mold is pressed at 500 MPa for 20 minutes to obtain a target material embryo.

[0122] (5) The target material blank obtained in step (4) is placed in a box furnace and sintered at 1300°C for 10 hours; then cooled to room temperature at a cooling rate of 2°C / min.

[0123] Example

[0124] A fluorine-doped tin oxide target is provided, which is prepared using the above-mentioned method for preparing a fluorine-doped tin oxide target; the raw materials, proportions and preparation parameters of each embodiment are shown in Tables 1 to 3.

[0125] Comparative Example 1

[0126] A fluorine-doped tin oxide target is provided, prepared using the aforementioned method for preparing a fluorine-doped tin oxide target. The primary difference from the embodiment is that the raw metal fluoride material uses low-melting-point SnF2 powder. Specific ratios and preparation parameters are shown in Table 1.

[0127] Comparative Example 2

[0128] A fluorine-doped tin oxide target is provided, prepared using the aforementioned method for preparing a fluorine-doped tin oxide target. The primary difference from the embodiment is that the raw metal fluoride material uses BaF2 powder with a large metal cation radius. Specific ratios and preparation parameters are shown in Table 1.

[0129]

Preparation of fluorine-doped tin oxide (FTO) thin films

[0130] A radio frequency magnetron sputtering device was used to coat the fluorine-doped tin oxide target provided in each embodiment and comparative example. The coating conditions were 30 W, 0.4 Pa, 27 min, and 180° C.

[0131] Table 1

[0132] Table 2

[0133] Table 3

[0134] Experimental example

[0135] The properties of the fluorine-doped tin oxide targets and films prepared in the examples and comparative examples were tested.

[0136] 1. Target material density: Use Archimedes drainage method to test target material density;

[0137] 2. Carrier concentration, mobility and resistivity of the film: Use Hall tester to test the carrier concentration, mobility and resistivity of the film;

[0138] 3. Film thickness: Use SEM to determine the thickness of the film;

[0139] 4. Transmittance of the film: Use a spectrophotometer to test the transmittance of the film;

[0140] The test results are shown in Tables 4 to 6.

[0141] Table 4

[0142] From the results in Table 4 we can see that:

[0143] In Example 1 and Example 3, the density of the target material is significantly improved due to the use of sintering aids;

[0144] Compared with Comparative Example 1 and Comparative Example 2, Example 1 to Example 5 have significantly improved carrier concentration, mobility, resistivity and transmittance.

[0145] This shows that the solution of the present application can effectively improve the density of the fluorine-doped tin oxide target and the photoelectric performance of the fluorine-doped tin oxide film.

[0146] Furthermore, compared with Comparative Example 1 and Comparative Example 2, Examples 1 to 5 have lower thickness.

[0147] Further, please refer to the drawings in the specification. Figure 2 shows the SEM image of the target material prepared in Example 1; Figure 3 shows the SEM image of the target material prepared in Comparative Example 1; and Figure 4 shows the SEM image of the target material prepared in Example 2.

[0148] From the comparison of Figures 2 and 3 , it can be seen that the target material prepared in Example 1 has smaller grain size, more uniform grain shape, and a denser target material. From the comparison of Figures 2 and 4 , it can be seen that the target material prepared in Example 1 has a higher density.

[0149] FIG5 and FIG6 respectively show the SEM images of the target materials prepared in Example 3 and Example 4; the target material in Example 3 has a higher density.

[0150] Furthermore, from the comparison between Example 1 and Example 2, it can be seen that when no sintering aid is added, the density, thin film carrier concentration, mobility, resistivity and transmittance of the target material decrease.

[0151] Furthermore, from the comparison between Example 1 and Example 3, it can be seen that when no metal oxide is added, the density, thin film carrier concentration, mobility, resistivity and transmittance of the target material decrease.

[0152] Furthermore, from the comparison between Example 1 and Example 4, it can be seen that when no sintering aid and no metal oxide are added, the density, thin film carrier concentration, mobility, resistivity and transmittance of the target material decrease.

[0153] Furthermore, compared with Example 4, Example 5 can be seen that the raw material particle size is smaller and the composition of the sample is more uniform.

[0154] Further, referring to the drawings in the specification, FIG14 shows a comparison of transmittance spectra of the films of Example 1 and Comparative Example 1.

[0155] It can be seen from FIG. 14 that the film transmittance of Example 1 is better.

[0156] Further, referring to the drawings in the specification, FIG15 shows a comparison of the absorption rate spectra of the films of Example 1 and Comparative Example 1.

[0157] It can be seen from FIG. 15 that the film of Example 1 has a better absorption rate.

[0158] Table 5

[0159] From the results in Table 5 we can see that:

[0160] The target material density, carrier concentration, mobility, resistivity and transmittance of Examples 6 to 9 are significantly improved.

[0161] This shows that the solution of the present application can effectively improve the photoelectric performance of the fluorine-doped tin oxide target.

[0162] Further, please refer to the accompanying drawings of the specification; Figure 7 shows a SEM image of the target material prepared in Example 6. Figure 8 shows a SEM image of the target material prepared in Example 7. Figure 9 shows a SEM image of the target material prepared in Example 8 of the present application.

[0163] From the comparison of FIG7 , FIG8 , and FIG9 , it can be seen that the target material prepared in Example 6 has a smaller grain size, a more uniform grain shape, and a denser target material.

[0164] FIG10 shows an SEM image of the target material prepared in Example 9 of the present application; the target material prepared in Example 9 has excellent density.

[0165] Further, referring to the drawings in the specification, FIG16 shows a comparison of the transmittance spectra of the target materials of Example 8 and Comparative Example 1.

[0166] It can be seen from FIG. 16 that the target material of Example 8 has better transmittance.

[0167] Further, referring to the drawings in the specification, FIG17 shows a comparison of the absorption rate spectra of the target materials of Example 8 and Comparative Example 1.

[0168] It can be seen from FIG. 17 that the target material of Example 8 has a better absorption rate.

[0169] Table 6

[0170] From the results in Table 6 we can see that:

[0171] The target material density, thin film carrier concentration, mobility, resistivity, and transmittance of Examples 10 to 13 are all significantly improved.

[0172] This shows that the solution of the present application can effectively improve the density of the fluorine-doped tin oxide target and the photoelectric performance of the fluorine-doped tin oxide film.

[0173] Further, please refer to the accompanying drawings of the specification; Figure 11 shows a SEM image of the target material prepared in Example 10. Figure 12 shows a SEM image of the target material prepared in Example 11. Figure 13 shows a SEM image of the target material prepared in Example 12 of the present application.

[0174] From the comparison of FIG11 , FIG12 , and FIG13 , it can be seen that the target material prepared in Example 10 has a smaller grain size, a more uniform grain shape, and a denser target material.

[0175] Further, referring to the drawings in the specification, FIG18 shows a comparison of transmittance spectra of the films of Example 12 and Comparative Example 1.

[0176] As can be seen from FIG. 18 , the film transmittance of Example 11 is better.

[0177] Further, referring to the drawings in the specification, FIG19 shows a comparison of the absorption rate spectra of the films of Example 12 and Comparative Example 1.

[0178] As can be seen from FIG. 19 , the film of Example 12 has a better absorption rate.

[0179] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a fluorine-doped tin oxide target, characterized in that: include: The powder mixture of the raw materials is pressed into a shape and then sintered; The powder mixture comprises: 70wt.% to 99.9wt.% SnO2, 0.1wt.% to 10wt.% metal fluoride; 0wt.%~10wt.% metal oxide; 0wt.%~10wt.% sintering aid; The melting point of the metal fluoride is greater than 800°C.

2. The method for preparing a fluorine-doped tin oxide target according to claim 1, characterized in that: The metal ion radius of the metal fluoride is less than 120 pm.

3. The method for preparing a fluorine-doped tin oxide target according to claim 1 or 2, characterized in that: The metal fluoride includes at least one of alkali metal fluoride, alkaline earth metal fluoride, lanthanide metal fluoride, YF3, TiF3, MnF2, FeF3, CoF2, NiF2, CuF, ZnF2 or CdF2.

4. The method for preparing a fluorine-doped tin oxide target according to claim 1 or 2, characterized in that: The metal fluoride is preferably at least one of LiF, MgF2, ScF3, TiF3, CrF3, MnF2, FeF3, CoF2, NiF2, CuF2, ZnF2, InF3, YF3, LaF3 or NdF3.

5. The method for preparing a fluorine-doped tin oxide target according to claim 1, characterized in that: The metal oxide includes at least one of Ta2O5, Nb2O5, Nb2O4, Sb2O5, Sb2O3, MoO3, WO3, WO2, V2O5 or V2O3.

6. The method for preparing a fluorine-doped tin oxide target according to claim 5, characterized in that: The sum of the fluorine content in the metal fluoride and the metal ion content in the metal oxide is less than 10 mol%.

7. The method for preparing a fluorine-doped tin oxide target according to claim 1, characterized in that: The sintering aid includes at least one of ZnO, MnO, TiO2, Nb2O5, Co2O3, Sb2O5, Sb2O3, Li2O, CuO, Ca2O3, Fe2O3 or FeO.

8. The method for preparing a fluorine-doped tin oxide target according to claim 1, characterized in that: The particle size of the powder mixture is 20nm-20μm.

9. The method for preparing a fluorine-doped tin oxide target according to claim 1, characterized in that: The sintering comprises: Heat the raw material powder mixture at 1000℃~1600℃ for 120min~3000min; Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

10. The method for preparing a fluorine-doped tin oxide target according to claim 1 or 9, characterized in that: The compression molding comprises: The powder mixture of the raw materials is placed in a mold and pressed at a pressure of 50 MPa to 800 MPa for 5 min to 30 min.

Images