Preparation method of fluorine-doped tin oxide target material

Abstract

The invention relates to the field of materials, in particular to a preparation method of a fluorine-doped tin oxide target material. Carrying out compression molding on the powder mixture of the raw materials and sintering; the powder mixture comprises the following components in percentage by weight: 70 to 99.9 percent of SnO2 and 0.1 to 10 percent of metal fluoride; 0 wt.% to 10 wt.% of a metal oxide; 0 wt.% to 10 wt.% of a sintering aid; the melting point of the metal fluoride is greater than 800 DEG C. According to the preparation method of the fluorine-doped tin oxide target material provided by the invention, a high-melting-point (gt; compared with the prior art, the metal fluoride with high temperature (800 DEG C) is used as a fluorine source of the fluorine-doped tin oxide target instead of stannous fluoride, so that the problem of decomposition of the metal fluoride in the high-temperature sintering process of the target is fundamentally solved, the control precision of the components of the target is improved, and the photoelectric property of the fluorine-doped tin oxide film can be effectively improved.

Description

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] In 2 O 3 The most commonly used transparent conductive oxide (TCO) in the industry is the indium-based transparent conductive material. 2 O 3 Due to its instability in reducing atmospheres and relatively high humidity air environments, tin oxide-based TCO films have been developed and utilized in recent years as a substitute for 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] At present, the main methods for preparing FTO films include sol hydrothermal method, spray pyrolysis method, chemical vapor deposition (CVD) and physical vapor deposition (PVD). Among them, physical vapor deposition methods (PVD), such as magnetron sputtering (MS), reactive plasma deposition (RPD), ion beam sputtering (IS), etc., have been widely used due to their low cost, simple process, compatibility with low-temperature processes, 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 industry for preparing fluorine-doped tin oxide (FTO) thin films by physical vapor deposition (PVD) is a non-metallic target, which is made by mixing tin oxide powder and stannous fluoride powder and pressing them at high temperature. However, the photoelectric performance of fluorine-doped tin oxide thin films prepared by this method is difficult to be further improved. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method for preparing a fluorine-doped tin oxide target.

[0006] The present application provides a method for preparing a fluorine-doped tin oxide target, comprising:

[0007] The powder mixture of the raw materials is pressed into a shape and then sintered;

[0008] The powder mixture includes: 70wt.%~99.9wt.%SnO 2 , 0.1wt.%~10wt.% metal fluoride; 0wt.%~10wt.% metal oxide; 0wt.%~10wt.% sintering aid;

[0009] The melting point of metal fluorides is greater than 800°C.

[0010] 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 very little fluorine content in the target and it is difficult to accurately control. As a result, it is 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.

[0011] In other embodiments of the present application, the metal ion radius of the metal fluoride is less than 120 pm.

[0012] In other embodiments of the present application, the metal fluoride includes alkali metal fluoride, alkaline earth metal fluoride, lanthanide metal fluoride, YF 3 、TiF 3 、MnF 2 , FeF 3 , CoF 2 、NiF 2 , CuF, ZnF 2 or CdF 2 At least one of .

[0013] In other embodiments of the present application, the metal fluoride is preferably LiF, MgF 2 ScF 3 、TiF 3 ,CrF 3 、MnF 2 , FeF 3 , CoF 2 、NiF 2 ,CuF 2 、ZnF 2 、InF 3 , YF 3 、LaF 3 or NdF 3 At least one of .

[0014] In other embodiments of the present application, the metal oxide includes Ta 2 O 5 , Nb 2 O 5 , Nb 2 O4 , Sb 2 O 5 , Sb 2 O 3 、MoO 3 , WO 3 , WO 2 、V 2 O 5 or V 2 O 3 At least one of .

[0015] 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%.

[0016] In other embodiments of the present application, the sintering aid includes: ZnO, MnO, TiO 2 , Nb 2 O 5 、Co 2 O 3 , Sb 2 O 5 , Sb 2 O 3 , Li 2 O, CuO, Ca 2 O 3 , Fe 2 O 3 Or at least one of FeO.

[0017] In other embodiments of the present application, the particle size of the powder mixture is 20 nm-20 μm.

[0018] In other embodiments of the present application, sintering includes:

[0019] Heat the raw material powder mixture at 1000℃~1600℃ for 120min~3000min;

[0020] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0021] In other embodiments of the present application, the compression molding includes:

[0022] 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

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the use of metal cations less than 120 pm incorporated into the tin oxide lattice provided in an embodiment of the present application;

[0025] Figure 2 The SEM image of the target material prepared in Example 1 of the present application is shown;

[0026] Figure 3 The SEM image of the target material prepared in Comparative Example 1 is shown;

[0027] Figure 4 The SEM image of the target material prepared in Example 2 of the present application is shown;

[0028] Figure 5 The SEM image of the target material prepared in Example 3 of the present application is shown;

[0029] Figure 6 The SEM image of the target material prepared in Example 4 of the present application is shown;

[0030] Figure 7 The SEM image of the target material prepared in Example 6 of the present application is shown;

[0031] Figure 8 The SEM image of the target material prepared in Example 7 of the present application is shown;

[0032] Fig. 9 The SEM image of the target material prepared in Example 8 of the present application is shown;

[0033] Fig.10 The SEM image of the target material prepared in Example 9 of the present application is shown;

[0034] Fig.11 shows a SEM image of the target material prepared in Example 10;

[0035] Fig.12 shows a SEM image of the target material prepared in Example 11;

[0036] Fig.13 The SEM image of the target material prepared in Example 12 of the present application is shown;

[0037] Fig.14 The transmittance spectra of the films of Example 4 and Comparative Example 1 are compared;

[0038] Fig.15 The absorption rate spectrum comparison of the film of Example 4 and Comparative Example 1 is shown;

[0039] Fig.16 The transmittance spectra of the films of Example 8 and Comparative Example 1 are compared;

[0040] Fig.17 The absorption rate spectrum comparison of the film of Example 8 and Comparative Example 1 is shown;

[0041] Fig.18 The transmittance spectra of the films of Example 12 and Comparative Example 1 are compared;

[0042] Fig.19 A comparison of the absorbance spectra of the films of Example 12 and Comparative Example 1 is shown. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] 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 which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0045] 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, further definition and explanation thereof is not required in subsequent drawings.

[0046] 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 is the orientation or position relationship in which the product of the application is usually placed when in use, or is the orientation or position relationship commonly understood by technical personnel in this field. 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.

[0047] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a connection between the two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0048] The method of preparing fluorine-doped tin oxide target by high-temperature sintering of tin oxide powder and stannous fluoride powder, 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 very little fluorine content in the target and it is difficult to accurately control. As a result, it is difficult to further improve the photoelectric performance of the fluorine-doped tin oxide film.

[0049] The present application provides a method for preparing a fluorine-doped tin oxide target, comprising:

[0050] sintering the powder mixture of raw materials;

[0051] The powder mixture includes: 70wt.%~99.9wt.%SnO 2 , 0.1wt.%~10wt.% metal fluoride; 0wt.%~10wt.% metal oxide; 0wt.%~10wt.% sintering aid;

[0052] The melting point of metal fluorides is greater than 800°C.

[0053] The preparation method of the fluorine-doped tin oxide target provided in the present application uses metal fluorides 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 further effectively improving the photoelectric properties of the fluorine-doped tin oxide film.

[0054] Furthermore, in the current method of preparing fluorine-doped tin oxide targets by high-temperature sintering of tin oxide powder and stannous fluoride powder, in order to alleviate the problem of large-scale decomposition of stannous fluoride, hot isostatic pressing is usually used to apply mechanical excitation or spark plasma sintering is used to apply mechanical and plasma excitation to promote the sintering process and reduce the sintering time. However, the equipment used in such hot isostatic pressing and spark plasma sintering methods is very expensive, which greatly increases the difficulty of industrial application of fluorine-doped tin oxide targets (FTO targets).

[0055] The present application uses high melting point (>800°C) metal fluoride instead of stannous fluoride as the fluorine source of fluorine-doped tin oxide target, and for the first time realizes the use of normal pressure high temperature sintering method to prepare dense anion and cation co-doped fluorine tin oxide target, 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).

[0056] Furthermore, the present application scheme uses high melting point (>800°C) metal fluoride as the fluorine source of the fluorine-doped tin oxide target, which can simultaneously introduce metal ions into the target, induce the target grain size and shape refinement, and improve the target density. Applying it to prepare fluorine-doped tin oxide (FTO) thin film by physical vapor deposition (PVD) can eliminate the defect structure in the film, thereby improving the photoelectric performance of the film, improving the transmittance of the film, reducing the absorption of the film, increasing the carrier concentration of the film, increasing the mobility of the film, and reducing the resistivity of the film.

[0057] Furthermore, in some embodiments of the present application, a method for preparing a fluorine-doped tin oxide target comprises:

[0058] Step S1, preparing a powder mixture of raw materials.

[0059] The raw material powder mixture is ground to a particle size of 20 nm to 20 μm.

[0060] Further optionally, the powder mixture of the raw materials is ground to a particle size of 50 nm-10 μm.

[0061] Exemplarily, the powder mixture of the raw materials is ground to a particle size of 60 nm, 100 nm, 200 nm, 300 nm, 500 nm, 1 μm or 5 μm.

[0062] Further, in some embodiments of the present application, grinding includes:

[0063] After mixing all the raw materials, place them in a ball mill and add grinding balls;

[0064] Start the ball mill, set the speed to 100-800 rpm, grind for 3-20 minutes and then stop for 5-20 minutes;

[0065] Repeat the above steps 5-30 times.

[0066] 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.

[0067] Furthermore, in some embodiments of the present application, the ground powder mixture is also dried.

[0068] Further, in some embodiments of the present application, drying comprises:

[0069] The ground powder mixture is dried at a drying temperature of 70°C-120°C and a drying time of 50min-100min.

[0070] Exemplarily, drying includes: drying the ground powder mixture at a drying temperature of 100° C. and a drying time of 60 minutes.

[0071] In other optional embodiments of the present application, the particle size of each raw material may be ground to 20 nm-20 μm first, and then the raw materials may be mixed.

[0072] Step S2, pressing the powder mixture of the raw materials obtained in step S1 into a mold.

[0073] In some embodiments of the present application, the above-mentioned pressing molding includes: placing a powder mixture of raw materials in a mold, and pressing at 50MPa to 800MPa for 5min to 30min.

[0074] Further optionally, in some embodiments of the present application, the above-mentioned pressing molding includes: placing a powder mixture of raw materials in a mold, using 51MPa to 795MPa, and pressing for 6min to 29min.

[0075] Exemplarily, in some embodiments of the present application, the above-mentioned compression molding includes:

[0076] 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.

[0077] Step S3, sintering the powder mixture of the pressed raw materials obtained in step S2.

[0078] In some embodiments of the present application, the powder mixture includes: 70wt.% to 99.9wt.% SnO 2 , 0.1wt.% ~ 10wt.% metal fluoride; 0wt.% ~ 10wt.% metal oxide; 0wt.% ~ 10wt.% sintering aid.

[0079] Further optionally, in some embodiments of the present application, the powder mixture comprises: 71wt.% to 99.8wt.% SnO2 , 0.1wt.% ~ 10wt.% metal fluoride; 0.1wt.% ~ 10wt.% metal oxide; 0.1wt.% ~ 10wt.% sintering aid.

[0080] For example, in some embodiments of the present application, the powder mixture comprises: 99.9wt.% SnO 2 , 0.1wt.% metal fluoride; or, the above powder mixture includes: 99wt.% SnO 2 、0.5wt.%metal fluoride;0.5wt.%metal oxide。 Alternatively, the powder mixture includes: 99wt.%SnO 2 , 0.5wt.% metal fluoride; 0.25wt.% metal oxide, 0.25wt.% sintering aid.

[0081] Furthermore, in some embodiments of the present application, the melting point of the above-mentioned metal fluoride is greater than 800°C.

[0082] 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.

[0083] Furthermore, in some embodiments of the present application, the metal ion radius of the above-mentioned metal fluoride is less than 120 pm.

[0084] Since SnO 2 The formation energy of interstitial tin (Sni) is very low. A large amount of Sni 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 the optical and electrical properties of the film to deteriorate sharply.

[0085] Reference Figure 1 In the embodiment of the present application, the metal cations less than 120 pm are doped into the tin oxide target to reduce Sn i The amount of SnO 2 Defective structures generated by lattice relaxation and reduction of Sn 2+ i -V o Composite defects are beneficial to improve the optical and electrical properties of tin oxide-based films.

[0086] Furthermore, in some embodiments of the present application, when the amount of metal oxide added to the above-mentioned powder mixture is greater than 0wt.%, the metal fluoride and the 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 doping concentration of impurity ions, 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.

[0087] 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 0wt.%, 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.

[0088] Furthermore, by adding a sintering aid greater than 0 wt.% to the above-mentioned powder mixture, the additional use of an organic binder is avoided. Compared with conventional targets using a binder, the fluorine-doped tin oxide target prepared by the method of the present application has higher purity and better density.

[0089] Furthermore, in some embodiments of the present application, the metal fluoride includes alkali metal fluoride, alkaline earth metal fluoride, lanthanide metal fluoride, YF 3 、TiF 3 、MnF 2 , FeF 3 , CoF 2 、NiF 2 , CuF, ZnF 2 or CdF 2 At least one of .

[0090] 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.

[0091] Furthermore, in some embodiments of the present application, the above-mentioned alkaline earth metal fluorides include: calcium fluoride, magnesium fluoride, barium fluoride and strontium fluoride.

[0092] Furthermore, in some embodiments of the present application, the metal fluoride is preferably LiF, MgF 2 ScF 3 、TiF 3 ,CrF 3 、MnF 2 , FeF 3 , CoF 2 、NiF 2 ,CuF 2 、ZnF 2 、InF 3 , YF3 、LaF 3 or NdF 3 At least one of .

[0093] For example, in some embodiments of the present application, the metal fluoride in the aforementioned powder mixture is selected from LiF, MgF 2 ScF 3 、TiF 3 ,CrF 3 , MnF 2 , FeF 3 , CoF 2 、NiF 2 ,CuF 2 、ZnF 2 、InF 3 , YF 3 、LaF 3 or NdF 3 Any one of; or the metal fluoride in the aforementioned powder mixture is selected from LiF, MgF 2 or the metal fluoride in the aforementioned powder mixture is selected from ScF 3 、TiF 3 ,CrF 3 , MnF 2 or the metal fluoride in the aforementioned powder mixture is selected from YF 3 、LaF 3 、NdF 3 mixture.

[0094] The various raw materials in the above mixture can be mixed in any proportion.

[0095] Further, in some embodiments of the present application, the metal oxide includes Ta 2 O 5 , Nb 2 O 5 , Nb 2 O 4 , Sb 2 O 5 , Sb 2 O 3 、MoO 3 , WO 3 , WO 2 、V 2 O 5 or V 2 O 3 At least one of .

[0096] For example, in some embodiments of the present application, the metal oxide in the aforementioned powder mixture is selected from Ta 2O 5 , Nb 2 O 5 , Nb 2 O 4 , Sb 2 O 5 , Sb 2 O 3 、MoO 3 , WO 3 , WO 2 、V 2 O 5 or V 2 O 3 Any one of; or the metal oxide in the aforementioned powder mixture is Ta 2 O 5 , Nb 2 O 5 or the metal oxide in the aforementioned powder mixture is selected from Nb 2 O 4 , Sb 2 O 5 , Sb 2 O 3 or the metal oxide in the aforementioned powder mixture is selected from MoO 3 , WO 3 , WO 2 、V 2 O 5 and V 2 O 3 mixture.

[0097] The various raw materials in the above mixture can be mixed in any proportion.

[0098] 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%.

[0099] 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) film. 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 will also cause strong impurity absorption, seriously affecting the light transmittance of tin oxide.

[0100] 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, increasing the mobility of the film and reducing the resistivity of the film.

[0101] Furthermore, in some embodiments of the present application, the sintering aid includes: ZnO, MnO, TiO 2 , Nb 2 O 5 、Co 2 O 3 , Sb 2 O 5 , Sb 2 O 3 , Li 2 O, CuO, Ca 2 O 3 , Fe 2 O 3 Or at least one of FeO.

[0102] For example, in some embodiments of the present application, the sintering aid in the above powder mixture is selected from: ZnO, MnO, Sb 2 O 3 , Li 2 O, CuO, Ca 2 O 3 , Fe 2 O 3 or any one of FeO; or the sintering aid in the above powder mixture is a mixture of ZnO and MnO; or the sintering aid in the above powder mixture is TiO 2 , Nb 2 O 5 、Co 2 O 3 , Sb 2 O 5 or the sintering aid in the above powder mixture is Sb 2 O 3 , Li 2 O, CuO, Ca 2 O 3 , Fe 2 O 3 and a mixture of FeO.

[0103] The various raw materials in the above mixture can be mixed in any proportion.

[0104] It should be noted that, in some embodiments of the present application, Nb 2 O 5 It 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.

[0105] Since tin oxide controls the material transfer process during high-temperature sintering by non-densification mass transfer mechanisms such as surface diffusion and evaporation-condensation, these processes only promote pore coarsening and grain growth but are difficult to densify. The embodiment of the present application densifies the tin oxide target by adding a sintering aid.

[0106] Further, in some embodiments of the present application, sintering includes:

[0107] Heat the raw material powder mixture at 1000℃~1600℃ for 120min~3000min;

[0108] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0109] Further optionally, in some embodiments of the present application, sintering includes:

[0110] Heat the raw material powder mixture at 1010℃~1590℃ for 125min~2900min;

[0111] Then the temperature was lowered to room temperature at a cooling rate of 1°C / min to 5°C / min.

[0112] Illustratively, in some embodiments of the present application, sintering includes:

[0113] 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; 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.

[0114] The features and performance of the present application are further described in detail below in conjunction with the embodiments:

[0115]

Preparation of fluorine-doped tin oxide target

[0116] A method for preparing a fluorine-doped tin oxide target is provided, and the preparation is carried out according to the following steps:

[0117] (1) Weigh SnO according to the set ratio 2 , metal fluoride, metal oxide and sintering aid are mixed to obtain a mixture.

[0118] (2) placing the mixture in step (1) into 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 to obtain a powder mixture.

[0119] (3) drying the powder mixture obtained in step (2) at 100° C. for 2 h;

[0120] (4) placing the powder mixture dried in step (3) into a mold, and applying pressure to the mold for pressing; pressing at 500 MPa for 20 minutes to obtain a target material embryo.

[0121] (5) The target material blank obtained in step (4) is placed in a box furnace and sintered at 1300° C. for 10 h; then cooled to room temperature at a cooling rate of 2° C. / min.

[0122] Example

[0123] Provided is a fluorine-doped tin oxide target material, which is prepared by the above-mentioned method for preparing a fluorine-doped tin oxide target material; the raw materials, proportions and preparation parameters of each embodiment are shown in Tables 1 to 3.

[0124] Comparative Example 1

[0125] Provided is a fluorine-doped tin oxide target material, which is prepared by the above-mentioned method for preparing a fluorine-doped tin oxide target material; the main difference from the embodiment is that the raw material metal fluoride uses low melting point SnF 2 Powder. The specific ratio and preparation parameters are shown in Table 1.

[0126] Comparative Example 2

[0127] Provided is a fluorine-doped tin oxide target material, which is prepared by the above-mentioned method for preparing a fluorine-doped tin oxide target material; the main difference from the embodiment is that the raw material metal fluoride uses a large metal cation radius BaF 2 Powder. The specific ratio and preparation parameters are shown in Table 1.

[0128]

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

[0129] 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.

[0130] Table 1

[0131]

[0132] Table 2

[0133]

[0134] Table 3

[0135]

[0136] Experimental example

[0137] The properties of the fluorine-doped tin oxide targets and films prepared in the examples and comparative examples were tested.

[0138] 1. Target material density: Use Archimedes drainage method to test target material density;

[0139] 2. Carrier concentration, mobility and resistivity of the film: Use Hall tester to test the carrier concentration, mobility and resistivity of the film;

[0140] 3. Film thickness: Use SEM to determine the film thickness;

[0141] 4. Film transmittance: Use a spectrophotometer to test the film transmittance;

[0142] The test results are shown in Table 4 to Table 6.

[0143] Table 4

[0144]

[0145] From the results in Table 4, we can see that:

[0146] In Example 1 and Example 3, the density of the target material is significantly improved due to the use of sintering aids;

[0147] Compared with Comparative Example 1 and Comparative Example 2, the carrier concentration, mobility, resistivity and transmittance of Example 1 to Example 5 are significantly improved.

[0148] 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.

[0149] Furthermore, compared with Comparative Example 1 and Comparative Example 2, Examples 1 to 5 have lower thickness.

[0150] Further, please refer to the attached drawings of the specification. Figure 2 shows a SEM image of the target material prepared in Example 1; Figure 3 The SEM image of the target material prepared in Comparative Example 1 is shown; Figure 4 The SEM image of the target material prepared in Example 2 is shown.

[0151] Depend on Figure 2 and Figure 3 It can be seen from the comparison that the target material prepared in Example 1 has smaller grain size, more uniform grain shape, and the entire target material is denser. Figure 2 and Figure 4 It can be seen from the comparison that the target material prepared in Example 1 has a higher density.

[0152] Figure 5 and Figure 6The SEM images of the target materials prepared in Example 3 and Example 4 are shown respectively; the target material in Example 3 has a higher density.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] Furthermore, compared with Example 4, it can be seen that the raw material particle size is smaller and the composition of the sample is more uniform.

[0157] Further, please refer to the attached drawings of the specification. Fig.14 A comparison of transmittance spectra of the films of Example 1 and Comparative Example 1 is shown.

[0158] From the attached Fig.14 It can be seen that the film transmittance of Example 1 is better.

[0159] Further, please refer to the attached drawings of the specification. Fig.15 A comparison of the absorbance spectra of the films of Example 1 and Comparative Example 1 is shown.

[0160] From the attached Fig.15 It can be seen that the film absorption rate of Example 1 is better.

[0161] Table 5

[0162]

[0163]

[0164] From the results in Table 5, we can see that:

[0165] The target material density, carrier concentration, mobility, resistivity and transmittance of Examples 6 to 9 are significantly improved.

[0166] This shows that the solution of the present application can effectively improve the photoelectric performance of the fluorine-doped tin oxide target.

[0167] Further, please refer to the attached drawings of the specification; Figure 7 The SEM image of the target material prepared in Example 6 is shown. Figure 8The SEM image of the target material prepared in Example 7 is shown. Fig. 9 The SEM image of the target material prepared in Example 8 of the present application is shown.

[0168] Depend on Figure 7 , Figure 8 , Fig. 9 It can be seen from the comparison that the target material prepared in Example 6 has smaller grain size, more uniform grain shape, and the entire target material is denser.

[0169] Fig.10 The SEM image of the target material prepared in Example 9 of the present application is shown; the target material prepared in Example 9 has better compactness.

[0170] Further, please refer to the attached drawings of the specification. Fig.16 A comparison of the transmittance spectra of the target materials of Example 8 and Comparative Example 1 is shown.

[0171] From the attached Fig.16 It can be seen that the target material of Example 8 has better transmittance.

[0172] Further, please refer to the attached drawings of the specification. Fig.17 A comparison of the absorption rate spectra of the target materials of Example 8 and Comparative Example 1 is shown.

[0173] From the attached Fig.17 It can be seen that the target material in Example 8 has a better absorption rate.

[0174] Table 6

[0175]

[0176]

[0177] From the results in Table 6, we can see that:

[0178] The target material density, thin film carrier concentration, mobility, resistivity and transmittance of Examples 10 to 13 are significantly improved.

[0179] 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.

[0180] Further, please refer to the attached drawings of the specification; Fig.11 The SEM image of the target material prepared in Example 10 is shown. Fig.12 The SEM image of the target material prepared in Example 11 is shown. Fig.13 The SEM image of the target material prepared in Example 12 of the present application is shown.

[0181] Depend on Fig.11 , Fig.12 , Fig.13It can be seen from the comparison that the target material prepared in Example 10 has a smaller grain size, a more uniform grain shape, and a denser target material.

[0182] Further, please refer to the attached drawings of the specification. Fig.18 A comparison of the transmittance spectra of the films of Example 12 and Comparative Example 1 is shown.

[0183] From the attached Fig.18 It can be seen that the film transmittance of Example 11 is better.

[0184] Further, please refer to the attached drawings of the specification. Fig.19 A comparison of the absorbance spectra of the films of Example 12 and Comparative Example 1 is shown.

[0185] From the attached Fig.19 It can be seen that the film absorption rate of Example 12 is better.

[0186] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope 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°C to 1600°C for 120min to 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.

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