Indium gallium zinc oxide target material and preparation method and application thereof

Abstract

The invention discloses an indium gallium zinc oxide target material as well as a preparation method and application thereof. The indium gallium zinc oxide target material comprises the following components in parts by weight: 15-55 parts of indium oxide; 29 to 32 parts of gallium oxide; 25-54 parts of zinc oxide; and 0.01 to 5 parts of aluminum powder. The novel IGZO target material is prepared by reasonably adjusting the proportion of indium, gallium and zinc and the doping amount of the metal aluminum powder, so that the sintering temperature during preparation of the indium gallium zinc oxide target material can be reduced, and the prepared indium gallium zinc oxide film has high mobility and also has good stability when being used for a TFT (Thin Film Transistor) device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and in particular to an indium gallium zinc oxide target, its preparation method, and its application. Background Technology

[0002] In recent years, thin-film transistors (TFTs) have been extensively and deeply studied due to their widespread applications in smart cards, e-books, and panel display systems. Among the materials used in TFT manufacturing, amorphous silicon (a-Si) and low-temperature polycrystalline silicon (LTPS) are widely used. However, with the increasing demand for larger frame sizes and higher pixel resolution, transparent conductive oxide (TCO) materials have attracted increasing attention due to their inherent advantages such as larger energy band gaps, high transmittance, and carrier mobility. Since the concept of overlapping electron transport in unoccupied isotropic s orbitals in TCO materials was reported, transparent oxide semiconductors, including indium (In), gallium (Ga), and zinc (Zn), have been extensively studied due to their respective unoccupied 5s, 4s, and 4s orbitals. Among all known transparent oxide semiconductors, zinc oxide materials have the largest 3d... 10 4s 0 Gallium oxide (IGZO) is widely used in optoelectronic devices, electronic devices, and sensors. However, due to the unwanted zinc interstitial spaces and oxygen vacancies, it is difficult to control the carrier concentration of zinc oxide materials. To alleviate the inherent drawbacks of zinc oxide materials, gallium is doped into them to reduce oxygen vacancies and increase crystal structure. Therefore, IGZO thin films and IGZO targets have become core materials in the fabrication of display devices.

[0003] However, commercially available IGZO devices have a diameter close to 10 cm⁻¹. 2 ·V -1 ·S -1 While the mobility of IGZO films is high, the performance of these films still suffers from oxygen instability.

[0004] Therefore, it is necessary to develop a new indium gallium zinc oxide target material so that the prepared IGZO thin film has the characteristics of high mobility and good stability. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes an indium gallium zinc oxide target material, which enables the prepared IGZO thin film to have the characteristics of high mobility and good stability.

[0006] A second aspect of the present invention provides a method for preparing an indium gallium zinc oxide target.

[0007] A third aspect of the present invention provides an indium gallium zinc oxide thin film.

[0008] The fourth aspect of this invention provides an application of an indium gallium zinc oxide target.

[0009] According to a first aspect of the present invention, an indium gallium zinc oxide target material is provided, comprising the following components in parts by weight: Indium oxide 15-55 parts; Gallium oxide 29-32 parts; 25-54 parts of zinc oxide; 0.01 to 5 parts of aluminum powder.

[0010] According to a preferred embodiment of the present invention, the indium gallium zinc oxide target material comprises the following components in parts by weight: Indium oxide 35-55 parts; Gallium oxide 29-32 parts; 25-30 parts zinc oxide; 1-5 parts aluminum powder.

[0011] The indium gallium zinc oxide target material according to embodiments of the present invention has at least the following beneficial effects: This invention prepares a novel IGZO target by rationally adjusting the ratio of indium gallium zinc and the doping amount of aluminum powder. This not only reduces the sintering temperature when preparing the indium gallium zinc target, but also makes the prepared indium gallium zinc thin film have high mobility and good stability when used in TFT devices.

[0012] According to a second aspect of the present invention, a method for preparing an indium gallium zinc oxide target as described in the first aspect of the present invention is provided, comprising the following steps: S1. Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder and dispersant are mixed and ball-milled to obtain a mixed slurry; the mixed slurry is mixed with a binder and spray-granulated to obtain a mixed powder; S2. The mixed powder is cold isostatically pressed in a mold to obtain a preform; S3. The indium gallium zinc oxide target is obtained by sintering the preform.

[0013] According to a preferred embodiment of the present invention, in step S2, the pressure of the cold isostatic pressing is 200~250 MPa.

[0014] According to a preferred embodiment of the present invention, in step S2, the holding time of the cold isostatic pressing is 10~40 min.

[0015] According to a preferred embodiment of the present invention, in step S3, the sintering step includes: First, raise the temperature to 650℃~750℃ and hold for one stage, then raise the temperature to 1080℃~1410℃ and hold for another stage.

[0016] According to a preferred embodiment of the present invention, the heat preservation time of heat preservation I is 1 to 5 hours.

[0017] According to a preferred embodiment of the present invention, the heat preservation time of heat preservation II is 7~15h.

[0018] According to a preferred embodiment of the present invention, the ball milling parameters include: the ball milling media being water and zirconium beads, the zirconium beads having a particle size of 1~1.5 mm, and the zirconium bead to water ratio being 6:1~5:1. The ball milling time is 1~1.5 hours. According to a preferred embodiment of the present invention, the dispersant includes at least one of polyacrylamide, ammonium polymethacrylate, or ammonium citrate.

[0019] According to a preferred embodiment of the present invention, the adhesive comprises at least one of polyvinyl alcohol, polyvinyl butyral, or polyethylene oxide.

[0020] According to a preferred embodiment of the present invention, the amount of dispersant added is 0.3% to 0.5% based on the total mass of indium oxide powder, gallium oxide powder, zinc oxide powder and aluminum powder.

[0021] According to a preferred embodiment of the present invention, the amount of the binder added accounts for 1% to 2% of the total mass of the mixed slurry.

[0022] A third aspect of the present invention provides an indium gallium zinc oxide thin film, which is prepared from the indium gallium zinc oxide target material described in the first aspect of the present invention.

[0023] The fourth aspect of the present invention provides an application of the indium gallium zinc oxide target described in the first aspect of the present invention in the preparation of semiconductor materials.

[0024] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0025] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0026] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0027] In some embodiments, the present invention provides an indium gallium zinc oxide target material comprising the following components in parts by weight: Indium oxide 15-55 parts; Gallium oxide 29-32 parts; 25-54 parts of zinc oxide; 0.01 to 5 parts of aluminum powder.

[0028] In this invention, a novel IGZO target material is prepared by rationally adjusting the ratio of indium gallium zinc and the doping amount of aluminum powder. This not only reduces the sintering temperature when preparing the indium gallium zinc target material, but also makes the prepared indium gallium zinc thin film have high mobility and good stability when used in TFT devices.

[0029] In some embodiments, the indium gallium zinc oxide target comprises the following components in parts by weight: Indium oxide 35-55 parts; Gallium oxide 29-32 parts; 25-30 parts zinc oxide; 1-5 parts aluminum powder.

[0030] In this invention, when the composition of the indium gallium zinc oxide target is within the above-mentioned range, the TFT device prepared using the IGZO thin film prepared with the indium gallium zinc oxide target has higher mobility and stability.

[0031] In some embodiments, a method for preparing an indium gallium zinc oxide target as described in the first aspect of the present invention is provided, comprising the following steps: S1. Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder and dispersant are mixed and ball-milled to obtain a mixed slurry; the mixed slurry is mixed with a binder and spray-granulated to obtain a mixed powder; S2. The mixed powder is cold isostatically pressed in a mold to obtain a preform; S3. The indium gallium zinc oxide target is obtained by sintering the preform.

[0032] In some embodiments, in step S2, the pressure of cold isostatic pressing is 200~250 MPa. For example, the pressure of cold isostatic pressing is 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa, or any sub-range of any two of the above values.

[0033] In some embodiments, in step S2, the holding time for cold isostatic pressing is 10 to 40 minutes. For example, it includes 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, 30 minutes, 32 minutes, 35 minutes, 38 minutes, 40 minutes, or any sub-range composed of any two of the above values.

[0034] In some embodiments, step S3, the sintering step includes: First, raise the temperature to 650℃~750℃ and hold for one stage, then raise the temperature to 1080℃~1410℃ and hold for another stage.

[0035] In some embodiments, the heat preservation time of the heat preservation I is 1 to 5 hours. For example, the heat preservation time is 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or any sub-range of any two of the above values.

[0036] In some embodiments, the heat preservation time of heat preservation II is 7 to 15 hours. For example, the heat preservation time is 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, or any sub-range composed of any two of the above values.

[0037] In some embodiments, the ball milling parameters include: the ball milling media being water and zirconium beads, the zirconium beads having a particle size of 1~1.5 mm, and the zirconium bead to water ratio being 6:1~5:1. The ball milling time is 1~1.5 hours.

[0038] In some embodiments, the dispersant includes at least one of polyacrylamide, ammonium polymethacrylate, or ammonium citrate.

[0039] In some embodiments, the adhesive comprises at least one of polyvinyl alcohol, polyvinyl butyral, or polyethylene oxide.

[0040] In some embodiments, the amount of dispersant added is 0.3% to 0.5% based on the total mass of indium oxide powder, gallium oxide powder, zinc oxide powder, and aluminum powder. For example, it includes 0.3%, 0.4%, and 0.5%.

[0041] In some embodiments, the amount of binder added accounts for 1% to 2% of the total mass of the mixed slurry. For example, it includes 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, or any two of the above values.

[0042] In some embodiments, an indium gallium zinc oxide thin film is provided, which is prepared from the indium gallium zinc oxide target material described in the first aspect of the present invention.

[0043] In some embodiments, an application of the indium gallium zinc oxide target described in the first aspect of the present invention is provided in the preparation of semiconductor materials.

[0044] In the embodiments and comparative examples of the present invention, some of the raw materials of the present invention are as follows: Indium oxide powder, gallium oxide powder, and zinc oxide powder must have a purity of ≥99.99%.

[0045] Preparation of indium oxide powder: Indium oxide powder was prepared by chemical precipitation. The specific surface area of ​​the powder was measured, and the measured specific surface area value was within 12 m². 2 / g to 20m2 Between / g.

[0046] Gallium oxide powder, zinc oxide, and aluminum powder were all purchased from Shanghai McLean Biochemical Technology Co., Ltd., with product numbers G810511, 768612, and A742105, respectively.

[0047] Example 1 This example provides an indium gallium zinc oxide (IGZO) target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts indium oxide powder, 30 parts gallium oxide powder, 27 parts zinc oxide powder, and 0.01 parts aluminum powder.

[0048] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220 MPa.

[0049] 3) Sintering: The preform is placed flat in a sintering furnace under normal pressure. The temperature is increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature is increased to 1400℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace is cooled to room temperature to obtain the IGZO sputtering target.

[0050] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0051] Example 2 This example provides an IGZO target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts indium oxide powder, 30 parts gallium oxide powder, 27 parts zinc oxide powder, and 1 part aluminum powder.

[0052] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220MPa.

[0053] 3) Sintering: The preform is placed flat in a sintering furnace under normal pressure. The temperature is increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature is increased to 1300℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace is cooled to room temperature to obtain the IGZO sputtering target.

[0054] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0055] Example 3 This example provides an IGZO target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts indium oxide powder, 30 parts gallium oxide powder, 27 parts zinc oxide powder, and 3 parts aluminum powder.

[0056] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220 MPa.

[0057] 3) Sintering: The preform is placed flat in a sintering furnace under normal pressure. The temperature is increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature is increased to 1190℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace is cooled to room temperature to obtain the IGZO sputtering target.

[0058] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0059] Example 4 This example provides an IGZO target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts indium oxide powder, 30 parts gallium oxide powder, 27 parts zinc oxide powder, and 5 parts aluminum powder.

[0060] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220 MPa.

[0061] 3) Sintering: The preform is placed flat in a sintering furnace under normal pressure. The temperature is increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature is increased to 1080℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace is cooled to room temperature to obtain the IGZO sputtering target.

[0062] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0063] Comparative Example 1 This example provides an IGZO target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts of indium oxide powder, 30 parts of gallium oxide powder, 27 parts of zinc oxide powder, and 18.89 parts of aluminum oxide powder.

[0064] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220 MPa.

[0065] 3) Sintering: The preform was placed flat in a sintering furnace under normal pressure. The temperature was increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature was increased to 1510℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace was cooled to room temperature to obtain the IGZO sputtering target.

[0066] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0067] Comparative Example 2 This example provides an IGZO target material, the raw materials for which the IGZO target material is prepared are composed of the following components in parts by weight: 51 parts of indium oxide powder, 30 parts of gallium oxide powder, 27 parts of zinc oxide powder, and 1 part of aluminum oxide powder.

[0068] The preparation steps for the IGZO target are as follows: 1) Mixing: Indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder, and 0.4% dispersant polyacrylamide were mixed and poured into a grinding mill to obtain a slurry. The amount of pure water added was the same as the weight of the powder, and the zirconium beads used had a particle size of 1 mm. 1.5% binder polyvinyl alcohol was added to the slurry, and after stirring for 1.5 hours, it could be spray-granulated to obtain mixed oxide powder. 2) Molding: The above-mentioned mixed powder was filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a molding pressure of 220 MPa.

[0069] 3) Sintering: The preform is placed flat in a sintering furnace under normal pressure. The temperature is increased to 750℃ at a rate of 1.5℃ / min and held for 3 hours to complete the degreasing process. Then, the temperature is increased to 1425℃ at a rate of 0.5℃ / min and held for 7 hours to complete the sintering process. Finally, the furnace is cooled to room temperature to obtain the IGZO sputtering target.

[0070] 4) Processing: The sintered target material is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively. The resulting smooth target material is then fixed to a copper backing plate using an indium layer to complete the bonding process.

[0071] Performance testing The IGZO targets of Examples 1-4 and Comparative Examples 1-2 were used for the preparation of active layer thin film materials; the steps are as follows: In 10 -4 In a high-vacuum chamber at pressure Pa, a mixture of argon and oxygen (oxygen partial pressure 20%) was introduced for DC sputtering at a power of 2.9 W / cm². 2 The deposited film thickness was 50 nm, and it was annealed at 380 °C for 1 hour in air.

[0072] Finally, the electrical characteristics of the TFT device (a bottom-gate coplanar TFT device was fabricated by sequentially depositing films on a cleaned glass substrate using ITO as the electrode and silicon oxide as the insulating layer, using the IGZO target materials of Examples 1-4 and Comparative Examples 1-2) were tested using a Keythley 2636 semiconductor tester. The results are shown in Table 1.

[0073] Table 1

[0074] As shown in Table 1, TFT devices fabricated using the indium gallium zinc oxide target materials from Examples 1-4 of this invention exhibit high mobility and high stability when used as the active layer material. Furthermore, the addition of aluminum powder can lower the sintering temperature of the target material.

[0075] As seen in Comparative Example 1, in order to achieve the same level of migration rate as in the example, after replacing aluminum powder with alumina, the amount of alumina powder needs to be increased to 18.89 parts, and the sintering temperature needs to be higher.

[0076] Comparative Example 2 shows that, with the same weight of alumina and aluminum powder, its performance is worse than that of the embodiments of the present invention. It also cannot reduce the sintering temperature.

[0077] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An indium gallium zinc oxide target material, characterized by, The indium gallium zinc oxide target comprises the following components by weight: Indium oxide 15-55 parts; Gallium oxide 29-32 parts; Zinc oxide 25-54 parts; Aluminum powder 0.01-5 parts.

2. The indium gallium zinc oxide target of claim 1, wherein The indium gallium zinc oxide target comprises the following components by weight: Indium oxide 35-55 parts; Gallium oxide 29-32 parts; Zinc oxide 25-30 parts; Aluminum powder 1-5 parts.

3. A method of producing the indium gallium zinc oxide target according to claim 1 or 2, characterized by, The method comprises the following steps: S1. mixing indium oxide powder, gallium oxide powder, zinc oxide powder, aluminum powder and a dispersant to obtain a mixed slurry by ball milling; and mixing the mixed slurry and a binder to obtain a mixed powder by spray granulation; S2. cold isostatic pressing the mixed powder in a mold to obtain a green body; S3. sintering the green body to obtain the indium gallium zinc oxide target.

4. The production method according to claim 3, characterized by, In step S2, the pressure of the cold isostatic pressing is 200-250 MPa.

5. The preparation method according to claim 3, characterized in that, In step S2, the pressure holding time of the cold isostatic pressing is 10-40 min.

6. The preparation method according to claim 3, characterized in that, In step S3, the sintering comprises the following steps: firstly, heating to 650-750 °C for I, and then heating to 1080-1410 °C for II.

7. The preparation method according to claim 3, characterized in that, The dispersant comprises at least one of polyacrylamide, polyammonium methacrylate or ammonium citrate.

8. The preparation method according to claim 3, characterized in that, The binder comprises at least one of polyvinyl alcohol, polyvinyl butyral or polyethylene oxide.

9. An indium gallium zinc oxide thin film, characterized by, The indium gallium zinc oxide target is prepared by the method of claim 1 or 2.

10. Use of the indium gallium zinc oxide target of claim 1 or 2 in the preparation of a semiconductor material.

Images