An Al-ITZO target material, its preparation method and application

Abstract

This invention belongs to the field of semiconductor technology, specifically disclosing an Al-ITZO target material, its preparation method, and its applications. The raw materials for preparing the Al-ITZO target material of this invention include indium oxide, tin oxide, zinc oxide, and aluminum oxide, as well as binders and plasticizers. The Al-ITZO target material of this invention exhibits high ion mobility when used as a channel layer material in thin-film transistor (TFT) devices, with a maximum mobility reaching 38 cm⁻¹. 2 ·V ‑1 ·S ‑1 Compared to IGZO, the Al-ITZO target exhibits significant improvements, with an extremely low subthreshold swing (SS) value, demonstrating high stability. Furthermore, the Al-ITZO target of this invention has lower cost and a wider range of raw material sources. This invention also provides a method for preparing the Al-ITZO target and its applications.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an Al-ITZO target material, its preparation method, and its application. Background Technology

[0002] Flat panel displays have become indispensable electronic products in people's daily lives. New flat panel display technologies have been widely adopted due to their low power consumption, small size, and ease of circuit integration. Thin-film transistors (TFTs) are the core technology of emerging display industries such as active-matrix liquid crystal displays (AMLCDs) and active-matrix light-emitting diodes (AMOLEDs), offering advantages such as high responsivity, high brightness, and high contrast, and are widely used in the semiconductor field. The development of channel layer materials in TFT devices has mainly gone through four stages: amorphous silicon, polycrystalline silicon, organic semiconductors, and metal oxides. Among them, metal oxides have a wide band gap, and due to the orbital overlap of metal cations, metal oxide thin films exhibit high transmittance and mobility in the visible light range. ZnO-based oxide thin films are characterized by fast etching speed and low particle generation. Furthermore, due to their low annealing temperature and good deposition uniformity, they exhibit excellent performance in emerging display technologies.

[0003] Among ZnO-based materials in related technologies, IGZO (indium gallium zinc oxide) has long been used in mass production lines due to its high mobility and excellent stability, but its mobility remains at 10 cm⁻¹. 2 ·V -1 ·S -1 The current technology, with its limited mobility, cannot meet the demands of increasingly sophisticated high-mobility and high-refresh-rate displays. While IZO films, developed later, achieve even higher mobility, maintaining device stability often requires the incorporation of rare-earth elements as carrier suppressors, undoubtedly increasing production costs. Furthermore, current ITZO (indium tin zinc oxide) films exhibit significantly higher mobility than IGZO films due to the large orbital overlap of In and Sn atoms, which facilitates carrier transport. However, the challenge of simultaneously achieving high mobility and high stability remains.

[0004] Therefore, there is an urgent need for a new type of target material that can be used to prepare conductive oxide thin films for TFT devices by magnetron sputtering, in order to meet the requirements of high mobility and high stability of new display technologies. 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 present invention provides an Al-ITZO target. The Al-ITZO target of the present invention exhibits high electron mobility when used as a channel layer material in thin-film transistor (TFT) devices, with a maximum mobility reaching 38 cm⁻¹. 2 ·V -1 ·S -1 Compared to IGZO, the Al-ITZO target exhibits a significant improvement. The subthreshold swing (SS) value of this Al-ITZO target is extremely low, demonstrating the advantage of high stability. Furthermore, the Al-ITZO target of this invention has lower cost and a wider range of raw material sources.

[0006] This invention also provides a method for preparing Al-ITZO targets.

[0007] This invention also provides applications of Al-ITZO targets.

[0008] In a first aspect, the present invention provides an Al-ITZO target material, the raw materials for which include indium oxide, tin oxide, zinc oxide and aluminum oxide.

[0009] According to specific embodiments of the present invention, the Al-ITZO target material provided by the present invention has high mobility and excellent stability, and the raw materials for preparation are widely available and the production cost is low.

[0010] In ITZO targets, increasing the atomic proportion of In or Sn decreases the average distance between the two atoms, increases the overlap of the 5s orbitals forming the conduction band, and leads to an increasing electron mobility. However, if the proportion of In or Sn is further increased, the ion-sorting effect of Zn in the film weakens, the film crystallinity increases, the appearance of grain boundaries hinders electron transport, and excess atoms form new scattering centers, resulting in a decrease in mobility. The Al-ITZO target of this invention uses appropriate proportions of indium oxide, tin oxide, and zinc oxide, achieving high mobility.

[0011] Oxygen vacancies are trapped states existing in the channel layer, inevitably trapping transported electrons or holes, thus affecting device stability. This invention involves doping ITZO with an appropriate amount of alumina, resulting in an Al-ITZO target with a significantly lower SS value compared to an undoped ITZO target, achieving higher device stability. This is likely because the high binding energy between Al and O atoms suppresses oxygen vacancies in the film, reducing the number of oxygen vacancies in the bulk and thus contributing to improved device stability.

[0012] According to some embodiments of the present invention, the raw materials for preparation include, by weight, 51-59 parts of indium oxide, 11-19 parts of tin oxide, 26-34 parts of zinc oxide and 2-16 parts of aluminum oxide.

[0013] According to some embodiments of the present invention, the raw materials for preparation further include binders and plasticizers.

[0014] According to some embodiments of the present invention, the raw materials for preparation further include 0.5 to 2 parts of binder and 0.5 to 2 parts of plasticizer.

[0015] According to some embodiments of the present invention, preferably, the raw materials for preparation include, by weight, 52-58 parts indium oxide, 12-18 parts tin oxide, 27-33 parts zinc oxide, 4-12 parts aluminum oxide, 0.5-2 parts binder, and 0.5-2 parts plasticizer.

[0016] According to some embodiments of the present invention, more preferably, the raw materials for preparation include, by weight, 53-57 parts of indium oxide, 13-17 parts of tin oxide, 28-32 parts of zinc oxide, 6-9 parts of aluminum oxide, 0.8-1.2 parts of binder and 0.8-1.2 parts of plasticizer.

[0017] According to some embodiments of the present invention, the indium oxide is indium oxide powder.

[0018] According to some embodiments of the present invention, the specific surface area of ​​the indium oxide powder is 6 m². 2 / g~20m 2 / g.

[0019] According to some embodiments of the present invention, the tin oxide is tin oxide powder.

[0020] According to some embodiments of the present invention, the specific surface area of ​​the tin oxide powder is 10 m². 2 / g~25m 2 / g.

[0021] According to some embodiments of the present invention, the zinc oxide is zinc oxide powder.

[0022] According to some embodiments of the present invention, the alumina is alumina powder.

[0023] According to some embodiments of the present invention, the adhesive is at least one of polyvinyl alcohol (PVA), ammonium polyacrylate, or polyvinyl butyral.

[0024] According to some embodiments of the present invention, the adhesive comprises polyvinyl alcohol.

[0025] According to some embodiments of the present invention, the plasticizer is at least one selected from polyethylene glycol (PEG), methyl phthalate, and polyvinylpyrrolidone.

[0026] According to some embodiments of the present invention, the plasticizer includes polyethylene glycol.

[0027] A second aspect of the present invention provides a method for preparing the Al-ITZO target material described in the first aspect of the present invention, comprising the following steps:

[0028] S1. Mix and grind the various metal oxide raw materials, then add binder and plasticizer and mix.

[0029] S2. Cold isostatic pressing, debinding and sintering, to obtain Al-ITZO target material.

[0030] According to specific embodiments of the present invention, the Al-ITZO target preparation method provided by the present invention is simple and efficient, with high raw material utilization, and the Al-ITZO target obtained has all the advantages of the Al-ITZO target of the first aspect of the present invention.

[0031] According to some embodiments of the present invention, after grinding in step S1, the specific surface area of ​​the resulting mixed powder is 10–25 m². 2 / g.

[0032] According to some embodiments of the present invention, the grinding in step S1 is ball milling.

[0033] According to some embodiments of the present invention, the cold isostatic pressing pressure in step S2 is 100-250 MPa, and the holding time is 10-60 min.

[0034] According to some embodiments of the present invention, the cold isostatic pressing pressure in step S2 is 150-250 MPa, and the holding time is 20-40 min.

[0035] According to some embodiments of the present invention, the degreasing sintering in step S2 specifically involves holding at 650–750°C for 2–4 hours, holding at 900–1100°C for 6–10 hours, and holding at 1300–1500°C for 16–24 hours.

[0036] According to some embodiments of the present invention, the degreasing sintering in step S2 specifically involves placing the cold isostatically pressed preform in a sintering furnace, heating it to 650–750°C at a heating rate of 1–3°C / min under an oxygen atmosphere, holding it at that temperature for 2–4 hours to complete the degreasing process; heating it to 900–1100°C at a heating rate of 1–2°C / min, holding it at that temperature for 6–10 hours, and then heating it to 1300–1500°C at a heating rate of 0.5–2°C / min, holding it at that temperature for 16–24 hours.

[0037] According to some embodiments of the present invention, the indium oxide powder and the tin oxide powder are prepared by chemical precipitation.

[0038] A third aspect of the present invention provides the application of the Al-ITZO target material described in the first aspect of the present invention in the field of displays.

[0039] According to some embodiments of the present invention, the display field is a thin-film transistor (TFT).

[0040] A metal oxide thin film, prepared from the Al-ITZO target material.

[0041] According to some embodiments of the present invention, the mobility of the metal oxide thin film is 18–40 cm⁻¹. 2 ·V -1 ·S -1 .

[0042] According to some embodiments of the present invention, the mobility of the metal oxide thin film is 37–39 cm⁻¹. 2 ·V -1 ·S -1 .

[0043] According to some embodiments of the present invention, the subthreshold swing (SS) value of the metal oxide thin film is 0.15 to 0.8 V / dec.

[0044] According to some embodiments of the present invention, the subthreshold swing (SS) value of the metal oxide thin film is 0.15 to 0.6 V / dec.

[0045] A thin-film transistor comprising the Al-ITZO target.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] The Al-ITZO target of this invention uses appropriate proportions of indium oxide, tin oxide, and zinc oxide, achieving high mobility. This invention also dops the ITZO with an appropriate amount of aluminum oxide, resulting in an Al-ITZO target with a significantly lower SS value and higher device stability. By rationally controlling the content of indium oxide, tin oxide, zinc oxide, and aluminum oxide in the Al-ITZO target, this invention obtains an optimal Al-ITZO target for fabricating TFT devices with high mobility and high stability. Compared to IGZO targets and rare-earth-doped IZO targets in related technologies, this invention has the advantages of wider availability of raw materials and lower cost.

[0048] 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

[0049] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0050] Unless otherwise specified in the detailed implementation method, follow the standard conditions or the manufacturer's recommended conditions. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0051] In the specific implementation, both zinc oxide powder and aluminum oxide powder were purchased from Shanghai McLean Biochemical Technology Co., Ltd., with product numbers Z820825 and A766524, respectively.

[0052] Example 1

[0053] This embodiment provides an Al-ITZO target and its preparation method.

[0054] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 16 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0055] The binder is polyvinyl alcohol (PVA), and the plasticizer is polyethylene glycol (PEG). The average molecular weight of PVA is 10,000, and the average molecular weight of PEG is 40,000. Both are of analytical grade.

[0056] Indium oxide (IO) powder and tin oxide (TIO) powder can both be prepared by chemical precipitation (or commercially available products can be used). The preparation method is as follows: IO / TI granules are added to nitric acid and heated to dissolve completely. The solution is then slowly drawn into ammonia water to produce IO / TI hydroxide precipitate. The precipitate is thoroughly washed until neutral, then spray-granulated and calcined in a muffle furnace to obtain IO / TIO powder. The powder is then analyzed using a fully automated specific surface area analyzer, with each powder tested three times, and the average value is taken. The specific surface area of ​​IO powder is within 6m². 2 / g to 20m 2 The specific surface area of ​​tin oxide powder is between / g and 10m². 2 / g to 25m 2 Between / g.

[0057] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0058] 1) Mixed granulation:

[0059] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and water of equal mass to the powder were added sequentially. The mixture was ball-milled for 30 hours. The zirconium beads used had a particle size of 1 mm. The average specific surface area of ​​the mixture after ball milling was measured to be 19 m². 2 / g.

[0060] 2) Compression molding:

[0061] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a pressing pressure of 250MPa.

[0062] 3) Degreasing and sintering:

[0063] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 700°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 1000°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1400°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0064] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0065] 4) Processing binding:

[0066] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0067] Example 2

[0068] This embodiment provides an Al-ITZO target and its preparation method.

[0069] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 8 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0070] The binder and plasticizer are the same as in Example 1; the indium oxide powder and tin oxide powder are prepared in the same way as in Example 1.

[0071] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0072] 1) Mixed granulation:

[0073] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and pure water of equal mass to the powder were added sequentially. The mixture was ball-milled for 30 hours. The zirconium beads used had a particle size of 1 mm. The average specific surface area of ​​the mixture was measured to be 20 m². 2 / g.

[0074] 2) Compression molding:

[0075] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a pressing pressure of 200MPa.

[0076] 3) Degreasing and sintering:

[0077] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 750°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 1100°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1500°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0078] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0079] 4) Processing binding:

[0080] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0081] Example 3

[0082] This embodiment provides an Al-ITZO target and its preparation method.

[0083] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 4 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0084] The binder and plasticizer are the same as in Example 1; the indium oxide powder and tin oxide powder are prepared in the same way as in Example 1.

[0085] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0086] 1) Mixed granulation:

[0087] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and pure water of equal mass to the powder were added sequentially. The mixture was ball-milled for 30 hours. The zirconium beads used had a particle size of 1 mm. The average specific surface area of ​​the mixture was measured to be 18 m². 2 / g.

[0088] 2) Compression molding:

[0089] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes and 150MPa.

[0090] 3) Degreasing and sintering:

[0091] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 650°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 900°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1300°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0092] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0093] 4) Processing binding:

[0094] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0095] Example 4

[0096] This embodiment provides an Al-ITZO target and its preparation method.

[0097] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 2 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0098] The binder and plasticizer are the same as in Example 1; the indium oxide powder and tin oxide powder are prepared in the same way as in Example 1.

[0099] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0100] 1) Mixed granulation:

[0101] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and pure water of equal mass to the powder were added sequentially. The mixture was ball-milled for 30 hours. The zirconium beads used had a particle size of 1 mm. The average specific surface area of ​​the mixture was measured to be 20 m². 2 / g.

[0102] 2) Compression molding:

[0103] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a pressing pressure of 200MPa.

[0104] 3) Degreasing and sintering:

[0105] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 750°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 1100°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1500°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0106] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0107] 4) Processing binding:

[0108] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0109] Example 5

[0110] This embodiment provides an Al-ITZO target and its preparation method.

[0111] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 8 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0112] The binder and plasticizer are the same as in Example 1; the indium oxide powder and tin oxide powder are prepared in the same way as in Example 1.

[0113] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0114] 1) Mixed granulation:

[0115] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and pure water of equal mass to the powder were added sequentially, and the mixture was ball-milled. The zirconium beads used had a particle size of 1 mm. Based on Example 2, the ball milling time was reduced to achieve an average powder specific surface area of ​​10 m². 2 / g.

[0116] 2) Compression molding:

[0117] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a pressing pressure of 200MPa.

[0118] 3) Degreasing and sintering:

[0119] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 750°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 1100°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1500°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0120] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0121] 4) Processing binding:

[0122] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0123] Example 6

[0124] This embodiment provides an Al-ITZO target and its preparation method.

[0125] The raw materials for preparing the Al-ITZO target in this embodiment consist of the following components in parts by weight: 55 parts indium oxide powder, 15 parts tin oxide powder, 30 parts zinc oxide powder, 8 parts aluminum oxide powder, 1 part binder, and 1 part plasticizer.

[0126] The binder and plasticizer are the same as in Example 1; the indium oxide powder and tin oxide powder are prepared in the same way as in Example 1.

[0127] The preparation steps of the Al-ITZO target material in this embodiment are as follows:

[0128] 1) Mixed granulation:

[0129] Indium oxide powder, tin oxide powder, zinc oxide powder, and aluminum oxide powder, weighed according to the above-mentioned proportions, were mixed and poured into a ball mill. A binder, plasticizer, and pure water of equal mass to the powder were added sequentially, and the mixture was ball-milled. The zirconium beads used had a particle size of 1 mm. Based on Example 2, the ball milling time was increased to achieve an average powder specific surface area of ​​30 m². 2 / g.

[0130] 2) Compression molding:

[0131] The powder from step 1) is mixed and granulated and then filled into a 1m×0.5m×0.2m mold, sealed, and subjected to cold isostatic pressing for 30 minutes at a pressing pressure of 200MPa.

[0132] 3) Degreasing and sintering:

[0133] The preform formed in step 2) is placed flat in a sintering furnace, oxygen is introduced, and the temperature is raised to 750°C at a rate of 2°C / min and held for 3 hours to complete the degreasing process; then the temperature is raised to 1100°C at a rate of 1.5°C / min and held for 8 hours; then the temperature is raised to 1500°C at a rate of 1°C / min and held for 20 hours to complete the sintering process; finally, the preform is cooled to the same temperature in the furnace to obtain the Al-ITZO target material.

[0134] In this embodiment, further processing steps for the Al-ITZO target material are also included for subsequent practical use or measurement. Specifically, this includes:

[0135] 4) Processing binding:

[0136] The Al-ITZO target obtained in the above steps is placed in a lathe and polished with 400-grit and 800-grit grinding wheels respectively to obtain a smooth Al-ITZO target. The target is then fixed to a copper backing plate through an indium layer to complete the bonding process.

[0137] Comparative Example 1

[0138] This comparative example provides an ITZO target material and its preparation method.

[0139] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 55 parts of indium oxide powder, 15 parts of tin oxide powder, and 30 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0140] Comparative Example 2

[0141] This comparative example provides an ITZO target material and its preparation method.

[0142] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 55 parts of indium oxide powder, 17 parts of tin oxide powder, and 28 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0143] Comparative Example 3

[0144] This comparative example provides an ITZO target material and its preparation method.

[0145] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 55 parts of indium oxide powder, 13 parts of tin oxide powder, and 32 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0146] Comparative Example 4

[0147] This comparative example provides an ITZO target material and its preparation method.

[0148] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 55 parts of indium oxide powder, 11 parts of tin oxide powder, and 34 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0149] Comparative Example 5

[0150] This comparative example provides an ITZO target material and its preparation method.

[0151] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 57 parts of indium oxide powder, 15 parts of tin oxide powder, and 28 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0152] Comparative Example 6

[0153] This comparative example provides an ITZO target material and its preparation method.

[0154] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 53 parts of indium oxide powder, 15 parts of tin oxide powder, and 32 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0155] Comparative Example 7

[0156] This comparative example provides an ITZO target material and its preparation method.

[0157] The only difference between this comparative example and Example 2 is the mass fraction of some of the raw material components: this comparative example uses 51 parts of indium oxide powder, 15 parts of tin oxide powder, and 34 parts of zinc oxide powder, but does not use aluminum oxide powder. The remaining raw material components and preparation methods are the same as in Example 2.

[0158] Test case

[0159] The performance of the targets prepared in each embodiment and comparative example was tested. Specifically, after cleaning, films were deposited sequentially on the glass substrate, with ITO as the electrode and aluminum oxide as the insulating layer. Al-ITZO or ITZO of each embodiment and comparative example were used as the channel layer material to prepare bottom-gate coplanar TFT devices. The electrical characteristics of the TFT devices in each test group were tested using a Keythley 2636 semiconductor tester. The amount of target material used and the test results for each group are shown in Table 1.

[0160] Table 1. Results of target material usage and performance testing for each test group.

[0161]

[0162] In ITZO targets, increasing the atomic proportion of In or Sn decreases the average distance between the two atoms, increases the overlap of the 5s orbitals forming the conduction band, and leads to an increasing electron mobility. However, if the proportion of In or Sn is further increased, the ion-sorting effect of Zn in the film weakens, the film crystallinity increases, the appearance of grain boundaries hinders electron transport, and excess atoms form new scattering centers, resulting in a decrease in mobility. The Al-ITZO target of this invention uses appropriate proportions of indium oxide, tin oxide, and zinc oxide, achieving high mobility.

[0163] Oxygen vacancies are trapped states existing in the channel layer, inevitably trapping transported electrons or holes, thus affecting device stability. Subthreshold swing (SS) measures the trapped state density of a device; the lower the SS value, the higher the device stability. This invention involves doping ITZO with an appropriate amount of alumina, resulting in an Al-ITZO target with a significantly lower SS value compared to an undoped ITZO target, achieving higher device stability. This is likely because the high binding energy between Al and O atoms suppresses oxygen vacancies in the film, reducing the number of oxygen vacancies in the bulk and thus contributing to improved device stability.

[0164] Based on the test results of the test examples, aluminum oxide has a significant impact on the stability of TFT devices, while indium oxide and tin oxide also have a significant impact on device mobility. By rationally combining the contents of indium oxide, tin oxide, zinc oxide, and aluminum oxide in the Al-ITZO target, this invention obtains an optimal Al-ITZO target that can produce TFT devices with high mobility and high stability. Furthermore, compared with IGZO targets and rare-earth-doped IZO targets in related technologies, the solution of this invention has the advantages of wider availability of raw materials and lower cost.

[0165] The embodiments of the present invention have been described in detail above. 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. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An Al-ITZO sputtering target, characterized in that, The raw materials for preparation include, by weight, 51-59 parts indium oxide, 11-19 parts tin oxide, 26-34 parts zinc oxide, 2-8 parts aluminum oxide, 0.5-2 parts binder, and 0.5-2 parts plasticizer; The Al-ITZO target material is prepared by a method including the following steps: S1. Mix the indium oxide, tin oxide, zinc oxide, and aluminum oxide, grind them, add the binder and plasticizer, and mix to obtain a powder with an average specific surface area of ​​10-25 m². 2 / g mixture; S2. Cold isostatic pressing, debinding and sintering, to obtain Al-ITZO target material; The pressure of the cold isostatic pressing is 100~250MPa, and the holding time is 10~60min; The degreasing sintering process specifically involves: holding at 650-750℃ for 2-4 hours, holding at 900-1100℃ for 6-10 hours, and holding at 1300-1500℃ for 16-24 hours.

2. The Al-ITZO target material according to claim 1, characterized in that, The adhesive is at least one of polyvinyl alcohol, ammonium polyacrylate or polyvinyl butyral, and / or the plasticizer is at least one of polyethylene glycol, methyl phthalate or polyvinylpyrrolidone.

3. The application of the Al-ITZO target material as described in claim 1 or 2 in the field of displays.

4. A metal oxide thin film, characterized in that, It is made from the Al-ITZO target material as described in claim 1 or 2.

5. A thin-film transistor, characterized in that, Includes the Al-ITZO target material as described in claim 1 or 2.

Images