Indium oxide-based evaporation target material as well as preparation method and application thereof

Abstract

The invention discloses an indium oxide-based evaporation target material as well as a preparation method and application thereof. The relative density of the indium oxide-based evaporation target material is 58%-66%; comprising the following components in percentage by weight: 3-5% of zinc oxide; 1%-2% of indium hydroxide; and the balance of indium oxide. The evaporation target material prepared by doping zinc oxide and indium oxide with specific content into indium oxide has stable relative density; the surface of the target material is smooth, and the conditions of cracks and powder falling can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of target materials, and in particular to an indium oxide-based evaporation target and a preparation method and application thereof. Background Art

[0002] At present, chemical vapor deposition method, spraying method, sol-gel method, vacuum evaporation method and magnetron sputtering method are all common preparation methods for transparent conductive oxide thin films. Among them, the vacuum coating method is a process in which, in a vacuum environment, a solid material is evaporated by heat energy, and the evaporated atoms or molecules condense on a substrate to form a thin film. The evaporation process involves three basic stages: evaporation, migration and condensation of the material. Under high vacuum conditions, the collision with gas molecules is reduced, and the evaporated atoms can freely migrate to the substrate surface and condense into a film.

[0003] The TCO thin film prepared by the vacuum evaporation method not only causes less damage to the substrate, can coat the film at a low temperature, has high film crystallinity, high deposition rate, but also the composition of the target material is easier to adjust. In the field of photovoltaic solar cells, the TCO thin film prepared by the RPD method can not only improve the photoelectric conversion efficiency of the solar cell, but also reduce the production cost, which is of great significance for realizing high-performance-price-ratio solar cell products.

[0004] However, the relative density of the existing indium zinc oxide evaporation target is unstable, resulting in problems such as powder falling, particle sputtering, and cracking during the coating process, which affect the final coating quality of the target material. Therefore, it is necessary to develop an evaporation target with stable relative density and smooth and crack-free surface to make the target material perform better in subsequent use. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, in the first aspect of the present invention, an indium oxide-based evaporation target is proposed, and the evaporation target has the characteristics of stable relative density and smooth and crack-free surface.

[0006] In the second aspect of the present invention, a preparation method of an indium oxide-based evaporation target is also provided.

[0007] In the third aspect of the present invention, an application of an indium oxide-based evaporation target is also provided.

[0008] An indium oxide-based evaporation target provided according to the first aspect embodiment of the present invention, the relative density of the indium oxide-based evaporation target is 58% to 66%; it includes the following components calculated by weight percentage:

[0009] Zinc oxide 3% to 5%; indium hydroxide 1% to 2%; the balance is indium oxide.

[0010] The indium oxide-based evaporation target provided according to the embodiment of the present invention has at least the following beneficial effects:

[0011] The evaporation target prepared by doping indium oxide with zinc oxide and indium hydroxide in specific contents according to the present invention has a stable relative density; the surface of the target is smooth, which can improve the situations of cracks and powder shedding.

[0012] According to a second aspect of the present invention, a method for preparing an indium oxide-based evaporation target is provided, including the following steps:

[0013] S1. Mix indium oxide powder and zinc oxide powder and carry out ball milling I; then add water and a dispersant and mix to carry out ball milling II to obtain a slurry, and spray-dry and granulate the slurry to obtain powder A;

[0014] S2. Sinter powder A for sintering I; carry out ball milling III on the sintered powder A and indium hydroxide powder to obtain powder B;

[0015] S3. Press the powder B to obtain a target blank; sinter the blank for sintering II to obtain the target.

[0016] The method for preparing an indium oxide-based evaporation target provided according to the embodiment of the present invention has at least the following beneficial effects:

[0017] In the present invention, indium oxide powder and zinc oxide powder are first mixed, ball milled and then sintered to obtain powder A, and then the evaporation target obtained by mixing powder A and indium hydroxide powder, pressing and then sintering II. By the method of secondary sintering, while keeping the surface of the target smooth, it can improve cracks and powder shedding, and keep the relative density of the target within the range of 58% - 66%.

[0018] According to a preferred embodiment of the present invention, the steps of the sintering I are as follows:

[0019] First, raise the temperature to temperature I for heat preservation I; then raise the temperature to temperature II for heat preservation II; then lower the temperature to temperature III for heat preservation III;

[0020] The temperature of temperature I is 500°C - 600°C; the temperature of temperature II is 1000°C - 1250°C; the temperature of temperature III is 800°C - 950°C.

[0021] According to a preferred embodiment of the present invention, the time of heat preservation I is 1h - 2h.

[0022] According to a preferred embodiment of the present invention, the time of heat preservation II is 0.5h - 1h.

[0023] According to a preferred embodiment of the present invention, the time of heat preservation III is 2h - 2.5h.

[0024] According to a preferred embodiment of the present invention, the heating rate for heating to temperature I is 2 to 5 °C / min.

[0025] According to a preferred embodiment of the present invention, the heating rate for heating to temperature II is 1 to 2 °C / min.

[0026] According to a preferred embodiment of the present invention, the heating rate for cooling to temperature III is 0.5 to 1 °C / min.

[0027] According to a preferred embodiment of the present invention, the steps of sintering II are as follows:

[0028] First, heat to temperature IV and hold for IV; then heat to temperature V and hold for V; then cool to temperature VI and hold for VI;

[0029] The temperature of temperature IV is 550 °C to 650 °C; the temperature of temperature V is 900 °C to 1100 °C; the temperature of temperature VI is 750 °C to 850 °C.

[0030] According to a preferred embodiment of the present invention, the holding time for holding IV is 0.5 h - 1 h.

[0031] According to a preferred embodiment of the present invention, the holding time for holding V is 3 h - 4 h.

[0032] According to a preferred embodiment of the present invention, the holding time for holding VI is 1.5 h - 2 h.

[0033] According to a preferred embodiment of the present invention, the heating rate for heating to temperature IV is 2 to 5 °C / min.

[0034] According to a preferred embodiment of the present invention, the heating rate for heating to temperature V is 1 to 2 °C / min.

[0035] According to a preferred embodiment of the present invention, the heating rate for cooling to temperature VI is 0.5 to 1 °C / min.

[0036] According to a preferred embodiment of the present invention, the conditions for ball milling II include a ball milling time of 30 to 50 h; a ball milling rotation speed of 1000 to 2000 r / min.

[0037] The conditions for ball milling I include a ball milling time of 0.5 to 2 h; a ball milling rotation speed of 1000 to 1800 r / min.

[0038] According to a preferred embodiment of the present invention, the conditions for ball milling III include a ball milling time of 5 to 10 h; a rotation speed of 1000 to 1500 r / min.

[0039] According to a preferred embodiment of the present invention, the pressure of pressing is 15 - 30 MPa.

[0040] According to a preferred embodiment of the present invention, the dispersant includes ammonium acrylate copolymer or polyvinylpyrrolidone.

[0041] The third aspect of the present invention provides an application of the indium oxide-based evaporation target described in the first aspect of the present invention in the preparation of a TCO film.

[0042] Other features and advantages of the present invention will be described in the subsequent description, and in part, will be obvious from the description, or will be understood by implementing the present invention. Detailed Embodiments

[0043] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in combination with the embodiments, but the present invention is not limited to these embodiments.

[0044] The reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in the technical field, unless otherwise specified.

[0045] Some raw materials in the examples and comparative examples of the present invention are as follows:

[0046] Zinc oxide powder: purity ≥ 99.99%, D50 is 10 - 100 μm.

[0047] Indium hydroxide powder, indium oxide powder: both are produced by Zhongshan Zhilong New Material Technology Co., Ltd., with a purity ≥ 99.99%.

[0048] Example 1

[0049] This example provides an indium oxide-based evaporation target, the component dosage of which is shown in Table 1, and its preparation method is as follows:

[0050] S1. Mix indium oxide powder and zinc oxide powder in proportion, first perform the first ball milling for 1 h to make the powder evenly mixed; then add deionized water and 3% dispersant (ammonium acrylate copolymer or polyvinylpyrrolidone) for the second ball milling for 40 h to obtain a mixed slurry. The ball milling speed is 1500 r / min for both; after the ball milling is completed, the slurry is spray-dried to granulate and obtain powder A;

[0051] S2. Sinter the powder A. In the first step of sintering, first raise the temperature to 550 °C at a heating rate of 3 °C / min and hold for 1 h; in the second step of sintering, raise the temperature to 800 °C at a heating rate of 1.5 °C / min and hold for 0.5 h; in the third step of sintering, introduce oxygen and raise the temperature to 1180 °C at a heating rate of 1 °C / min and hold for 4 h. After the holding is completed, cool down to 900 °C at a rate of 1 °C / min and hold for 2 h. After the holding is completed, stop the gas supply; finally, cool down to room temperature at a rate of 1 °C / min; Mix and ball-mill the sintered powder A with indium hydroxide powder for 8 h at a ball-milling speed of 1200 r / min to obtain powder B;

[0052] S3. Pour the powder B into a φ30 mm * 40 mm mold and press it to obtain a target blank under a pressure of 15 MPa. Perform secondary sintering on the blank. In the first step of sintering, first raise the temperature to 600 °C at a heating rate of 2 °C / min and hold for 1 h; in the second step, introduce oxygen and raise the temperature to 1000 °C at a heating rate of 1 °C / min and hold for 3 h. After the holding is completed, cool down to 800 °C at a rate of 1 °C / min, hold for 2 h, and stop the gas supply; finally, cool down to room temperature at a rate of 1 °C / min. After sintering and cooling, obtain an evaporation target.

[0053] Examples 2 - 5

[0054] Examples 2 - 5 provide a series of indium oxide-based evaporation targets, the component contents (mass percentages) of which are shown in Table 1, and their preparation methods are the same as those in Example 1.

[0055] Table 1

[0056] Example 1 Example 2 Example 3 Example 4 Example 5 Indium oxide 96％ 95％ 95％ 94％ 94％ Zinc oxide 3％ 3％ 4％ 4％ 5％ Indium hydroxide 1％ 2％ 1％ 2％ 1％

[0057] Comparative Example 1

[0058] This example provides an indium oxide-based evaporation target with component dosages of 97% indium oxide and 3% zinc oxide. The preparation method is the same as that in Example 1.

[0059] Comparative Example 2

[0060] This example provides an indium oxide-based evaporation target with the same component dosages as in Example 1, and the difference is that only the first step of sintering is carried out.

[0061] Comparative Example 3

[0062] This example provides an indium oxide-based evaporation target with component dosages of 98% indium oxide and 2% indium hydroxide. The preparation method is the same as that in Example 1.

[0063] Performance Test

[0064] The indium oxide-based evaporation targets prepared in Examples 1-5 and Comparative Examples 1-3 of the present invention were tested as follows; the results are shown in Table 2.

[0065] Relative density: The density was measured and calculated by the volume method using a vernier caliper, where the relative density is the ratio of the actual density of the target to the theoretical density.

[0066] Whether there are cracks or powder shedding: The cracks and powder shedding were observed visually. If the crack is less than 5 mm, it belongs to fine cracks; if it is between 5-10 mm, it belongs to medium cracks; if it is greater than 10 mm, it belongs to large cracks.

[0067] Powder shedding situation touch test:

[0068] Gently wipe the surface of the target with a lint-free cloth and check if there is any powder shedding. Record the degree of powder shedding (none, slight, severe).

[0069] No powder shedding: Touch the surface of the target with a lint-free cloth, and no powder falls off. There are no obvious particles or loose substances on the surface of the target.

[0070] Slight powder shedding: Gently touch the surface of the target with your hand, and a small amount of powder falls off. There is a slight granular feeling on the surface of the target, but it does not affect normal use.

[0071] Severe powder shedding: Touch the surface of the target with your hand, and a large amount of powder falls off. The granular feeling on the surface of the target is obvious, which will affect the quality of thin film deposition.

[0072] Shrinkage rate %: (Size of the target before sintering / Size of the target after sintering) * 100%. Since the relative density of the evaporation target is smaller than that of traditional targets such as sputtering targets, and the density is lower, it is difficult to process the target after sintering and it is easy to break. The smaller the shrinkage rate of the target, the smaller the influence on the size.

[0073] Table 2

[0074] Shrinkage rate % Relative density % Target appearance Crack and powder loss situation Example 1 0.03 60.06 Smooth No cracks and no powder loss Example 2 1.17 65.48 Relatively smooth No cracks and no powder loss Example 3 0.55 59.24 Relatively smooth No cracks and slight powder loss Example 4 1.07 64.95 Relatively rough No cracks and no powder loss Example 5 0.36 58.96 Relatively smooth No cracks and slight powder loss Comparative example 1 2.09 68.96 Relatively rough Medium cracks and slight powder loss Comparative example 2 2.89 67.23 Relatively rough Medium cracks and slight powder loss Comparative example 3 / / Rough Through crack of the target

[0075] It can be seen from the data in Table 2 that by comparing Examples 1, 3, 5 with 2, 4, it can be seen that the doping ratio of zinc oxide cannot be too high. If the doping ratio is too high, the doping elements and the indium oxide substrate cannot be evenly mixed and sintered, which will lead to a decrease in the final performance of the target and affect the use effect of the target. By comparing Examples 1-2, 3-4, it can be seen that the doping of indium hydroxide powder can increase the relative density of the target and will also have an impact on the shrinkage rate. Since indium hydroxide powder will gradually dehydrate during the sintering process and completely dehydrate at about 600 °C, the evaporation of water will hinder the densification process during the sintering of the target, thereby controlling the relative density of the target to be within the required range. Therefore, controlling zinc oxide and indium hydroxide in the present invention within the scope of the present invention can obtain a low-density evaporation target with better comprehensive effects.

[0076] The above has been described in detail in connection with the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. An indium oxide-based evaporation target, characterized in that, The relative density of the indium oxide-based evaporation target is 58% to 66%; it includes the following components calculated by weight percentage: Zinc oxide 3% to 5%; Indium hydroxide 1% to 2%; The balance is indium oxide.

2. A method for preparing an indium oxide-based evaporation target as described in claim 1, characterized in that, It includes the following steps: S1. Mix indium oxide powder and zinc oxide powder and carry out ball milling I; then add water and a dispersant and mix to carry out ball milling II to obtain a slurry, and spray-dry and granulate the slurry to obtain powder A; S2. Sinter powder A in sintering I; carry out ball milling III on the sintered powder A and indium hydroxide powder to obtain powder B; S3. Press the powder B to obtain a target blank; sinter the blank in sintering II to obtain the product.

3. The preparation method according to claim 2, characterized in that, The steps of the sintering I are as follows: First, heat up to temperature I and hold for insulation I; then heat up to temperature II and hold for insulation II; then cool down to temperature III and hold for insulation III; The temperature of the temperature I is 500°C to 600°C; the temperature of the temperature II is 1000°C to 1250°C; the temperature of the temperature III is 800°C to 950°C.

4. The preparation method according to claim 2 or 3, characterized in that, The time of the insulation I is 1h - 2h; and / or the time of the insulation II is 0.5h - 1h; and / or the time of the insulation III is 2h - 2.5h.

5. The preparation method according to claim 2 or 3, characterized in that, The steps of the sintering II are as follows: First, heat up to temperature IV and hold for insulation IV; then heat up to temperature V and hold for insulation V; then cool down to temperature VI and hold for insulation VI; The temperature of the temperature IV is 550°C to 650°C; the temperature of the temperature V is 900°C to 1100°C; the temperature of the temperature VI is 750°C to 850°C.

6. The preparation method according to claim 5, characterized in that, The time of the insulation IV is 0.5h - 1h; and / or the time of the insulation V is 3h - 4h; and / or the time of the insulation VI is 1.5h - 2h.

7. The preparation method according to claim 2, characterized in that, The conditions of the ball milling II include a ball milling time of 30 to 50h; a ball milling rotation speed of 1000 to 2000r / min.

8. The preparation method according to claim 2, characterized in that, The conditions of the ball milling III include a ball milling time of 5 to 10h; a rotation speed of 1000 to 1500r / min.

9. The preparation method according to claim 2, characterized in that, The pressure of the pressing is 15 - 30MPa.

10. The application of the indium oxide-based evaporation target according to claim 1 in the preparation of a TCO film.