High-performance semiconductor oxide IGGXO target material in display field and application method thereof

Abstract

The invention relates to the technical field of target materials, and provides a high-performance semiconductor oxide IGGXO target material in the display field and an application method thereof, which introduces a carrier which can be additionally provided by replacing with In < 3 + >, and a wider and better-dispersivity conduction band bottom is formed after the 4s orbital energy level of Ge is deeper than the 5s orbital energy level of In and the 2p orbital energy level of O is hybridized, so that the performance of the semiconductor oxide IGGXO target material is improved. Meanwhile, the forbidden band width can reach 5.0 eV or above, so that a ternary system formed by germanium oxide with higher visible light transmittance of the film is used as a substrate; meanwhile, indium sites are partially replaced by high-valence tin ions, sufficient free electrons are provided, and the carrier concentration is effectively regulated, controlled and improved; by means of the grain boundary pinning effect of the rare earth oxide Y2O3, the phenomena of composition segregation and phase separation in the sputtering process are remarkably inhibited while target grains are refined and the microstructure uniformity is improved.

Description

Technical Field

[0001] This invention relates to the field of target technology, and in particular to a high-performance semiconductor oxide IGGXO target for the display industry and its application method. Background Technology

[0002] With the rapid development of display technology towards higher resolution, higher refresh rates, lower power consumption, and greater flexibility, oxide semiconductor thin-film transistors (Oxide TFTs) have become the core technology driving next-generation liquid crystal displays (LCDs) and organic light-emitting diode displays (OLEDs) due to their advantages such as high mobility, good uniformity, and simple fabrication processes. Among them, indium gallium zinc oxide (IGZO) targets are the mainstream material for fabricating the active layer of TFTs.

[0003] However, existing IGZO-based sputtering targets and their thin films still have many inherent limitations, making it difficult to meet the demands of future ultra-high-end displays: First, their electron mobility still has room for improvement, restricting further breakthroughs in TFT switching speed and making it difficult to perfectly adapt to the fast signal response requirements of ultra-high-specification displays above 8K and 120Hz. Second, the stability and uniformity of the thin film need to be improved. During the sputtering process, component segregation and phase separation are prone to occur, resulting in a high defect state density in the thin film, which affects the threshold voltage stability of the device and the yield of the display panel.

[0004] To address the above issues, the industry has made various attempts to improve the single IGZO system, such as adjusting the In / Ga / Zn ratio or introducing a single dopant element. However, these methods often fail to simultaneously achieve high mobility, high stability, high uniformity, and controllable carrier concentration. Most improvement schemes suffer from limitations such as singular performance gains, narrow process windows, or high costs, and cannot systematically solve the aforementioned technical bottlenecks.

[0005] Therefore, there is an urgent need in this field to develop a novel composite semiconductor oxide target material that can achieve simultaneous optimization of multiple properties through multi-dimensional synergistic material design, so as to meet the stringent requirements of next-generation display technologies for high-performance and high-reliability TFT backplanes. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a high-performance semiconductor oxide IGGXO target material for the display field and its application method, thereby solving the problems in the background art.

[0007] To achieve the above objectives, the present invention provides a high-performance semiconductor oxide IGGXO target for the display field, comprising: 50-80 at% indium oxide powder, 5-30 at% gallium oxide powder, 5-20 at% germanium oxide powder, 0.1-2 at% zinc oxide powder, 0.1-2 at% tin oxide powder, and 0.1-2 at% yttrium oxide powder.

[0008] Preferably, it comprises: 65-75 at% indium oxide powder, 5-20 at% gallium oxide powder, 5-15 at% germanium oxide powder, 0.5-1 at% zinc oxide powder, 0.5-1 at% tin oxide powder, and 0.5-1 at% yttrium oxide powder.

[0009] Preferably, the indium oxide powder, gallium oxide powder, germanium oxide powder, zinc oxide powder, tin oxide powder, and yttrium oxide powder are all oxide powders with a purity of 99.99%.

[0010] A method for applying a high-performance semiconductor oxide IGGXO target in the display field includes a thin film preparation method:

[0011] Step 1: Mix various oxide powders with anhydrous ethanol at a solid-liquid ratio of 1:1.5, and grind them in a ball mill for 4-6 hours to obtain a uniform slurry;

[0012] Step 2, spray granulation: The slurry is centrifuged and spray granulated to obtain spherical particles;

[0013] Step 3: The granulated powder is formed into an integral target blank through cold isostatic pressing to reduce the risk of internal stress cracking in large-sized target materials;

[0014] Step 4, Two-stage atmospheric pressure sintering:

[0015] High-temperature densification stage: Increase the temperature to 1450-1500℃ at a rate of 5℃ / min and hold for 6-8 hours;

[0016] Grain control stage: Cool down to 1350℃ and hold for 40-45 hours;

[0017] Step 5: Precision machining, using diamond grinding wheels and chemical mechanical polishing to achieve a surface roughness Ra≤0.5μm and flatness ≤0.02mm / m for the target material;

[0018] Step 6, Magnetron sputtering deposition:

[0019] The system employs a medium-frequency magnetron sputtering system with a target-substrate distance of 60-80 mm, a working gas pressure of 0.5-1.0 Pa, an Ar:O2 ratio of 95:5, and a sputtering power density of 8-12 W / cm³. 2 Substrate temperature 200-300℃;

[0020] Step Six, Post-processing:

[0021] Rapid thermal annealing: In a N2 atmosphere, the temperature is increased to 400-450℃ at a rate of 20℃ / s and held for 30-60s to repair lattice defects during sputtering and improve carrier mobility to >50cm². 2 / (V·s).

[0022] Preferably, in step one, the ball mill speed is 300-400 rpm and the ball-to-material ratio is 5:1.

[0023] Preferably, the inlet temperature of the granulator in step two is 200-220℃, and the outlet temperature is 80-90℃.

[0024] Preferably, the isostatic pressure in step three is 200-250 MPa, and the holding time is 5-10 min.

[0025] The beneficial effects of this invention: This invention introduces a process that interacts with In into a binary system of indium oxide (In₂O₃), known for its high mobility, and gallium oxide (Ga₂O₃), known for its high stability. 3+ Substitution can provide additional charge carriers, and because the 4s orbital energy level of Ge is deeper than that of In, hybridization with the 2p orbital of O may form a wider and more diffuse conduction band bottom. This can significantly reduce the effective mass of electrons, thereby greatly improving the intrinsic mobility of charge carriers. At the same time, the band gap can reach 5.0 eV and above, resulting in higher visible light transmittance of the film. Using the ternary system of germanium oxide (GeO2) as the matrix, a multi-element synergistic doping strategy is used to achieve multi-dimensional performance improvements: introducing zinc ions (Zn). 2+ Optimizes amorphous network formation capability, improves film surface morphology and interface state characteristics, and significantly enhances carrier mobility uniformity and operational stability; simultaneously, it utilizes high-valence tin ions (Sn) 4+ Partially replacing indium sites provides ample free electrons, effectively regulating and increasing carrier concentration. Furthermore, by leveraging the grain boundary pinning effect of rare earth oxide Y2O3, it refines target grains and improves microstructure uniformity while significantly suppressing compositional segregation and phase separation during sputtering, thereby enhancing the consistency and process repeatability of large-area film formation.

[0026] This invention breaks through the traditional indium-gallium-zinc based material system such as IGZO, and innovatively uses indium oxide (In2O3), gallium oxide (Ga2O3), and germanium oxide (GeO2) to form a ternary host material. This is not a simple element substitution, but a design based on the unique electronic structure of GeO2, specifically the 4s orbital, aiming to simultaneously achieve ultra-high mobility and a wide optical bandgap, thus solving the problem of performance incompatibility from the material's fundamental source.

[0027] This invention, based on a ternary matrix, utilizes "Zn 2+ +Sn 4+ The multi-element synergistic doping strategy of "+Y2O3" achieves multifunctionality of a single material: Zn 2+ Doping: Responsible for improving the quality and interface states of amorphous networks, enhancing uniformity and stability; Sn 4+ Doping: As a highly efficient carrier donor, by substituting In 3+It provides precise and controllable electron concentration, solving the problem of carrier source under high mobility; Y2O3 doping: as a microstructure stabilizer, it uses its pinning effect to suppress grain growth and compositional segregation, ensuring the uniformity of large-area film formation and process repeatability.

[0028] This invention successfully optimizes multiple key properties on a single target material, achieving a breakthrough combination of "ultra-high mobility + high visible light transmittance + excellent uniformity and stability", which meets the comprehensive requirements of next-generation high-end displays for speed, image quality and yield. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] A high-performance semiconductor oxide IGGXO target for the display field includes indium oxide powder, gallium oxide powder, germanium oxide powder, zinc oxide powder, tin oxide powder, and yttrium oxide powder with a purity of 99.99%.

[0032] A method for applying a high-performance semiconductor oxide IGGXO target in the display field includes a thin film preparation method:

[0033] S1, various oxide powders are mixed with anhydrous ethanol at a solid-liquid ratio of 1:1.5, and then ground in a ball mill for 5 hours at a speed of 350 rpm and a ball-to-material ratio of 5:1 to obtain a uniform slurry;

[0034] S2, spray granulation: The slurry is centrifuged and sprayed to produce spherical particles. The inlet temperature of the granulator is 220℃ and the outlet temperature is 90℃.

[0035] S3, the granulated powder is formed into an integral target blank by cold isostatic pressing. The cold isostatic pressing pressure is 250MPa and the holding time is 10min.

[0036] S4, First stage sintering: High temperature densification stage: Heat up to 1500℃ at 5℃ / min, hold for 8h to promote particle diffusion;

[0037] S5, Second stage sintering: Cool down to 1350℃ and hold for 45 hours to inhibit excessive grain growth;

[0038] S6, precision machined, with diamond wheel grinding and chemical mechanical polishing, to achieve a target surface roughness Ra≤0.5μm and flatness≤0.02mm / m;

[0039] S7, magnetron sputtering deposition:

[0040] A medium-frequency magnetron sputtering system was used, with a target-substrate distance of 80 mm, a working gas pressure of 1.0 Pa, an Ar:O2 ratio of 95:5, and a sputtering power density of 12 W / cm³. 2 Substrate temperature 300℃;

[0041] S8, Post-processing:

[0042] Rapid thermal annealing: In a N2 atmosphere, the temperature is increased to 400-450℃ at a rate of 20℃ / s and held for 30-60s to repair lattice defects during sputtering and improve carrier mobility to >50cm². 2 / (V·s).

[0043] The formulations of Examples 1-6 and Comparative Example 1 are shown in the table below:

[0044]

[0045] To further compare the performance differences between Examples 1-6 and Comparative Example 1, the intrinsic properties of each target material were characterized as follows: the density of the target material was tested using the water displacement method; the resistivity of the target material was tested using a four-probe resistivity meter; the grain size of the target material was tested using a metallographic microscope after etching the cross-section of the target material with aqua regia; the thickness of the single film prepared with the corresponding target material was measured using a step meter; the carrier concentration and carrier mobility were characterized using a Hall effect meter; the transmittance under visible light was characterized using an ultraviolet spectrophotometer; the surface roughness of the film was characterized using an atomic force microscope; and the main components of the film, indium, gallium, and germanium, were detected using XPS.

[0046] The following table compares the test results of the target material and the thin film:

[0047]

[0048] Examples 1-6 demonstrate significantly superior overall performance compared to the conventional IGZO target material of Comparative Example 1. While maintaining a similar density, they exhibit lower resistivity and a more uniform and finer grain structure. Thin films prepared using this target material exhibit excellent uniformity, including consistent thickness distribution and a smooth surface, along with higher carrier concentration and mobility, and superior optical transmittance. Furthermore, the compositional deviation between the thin film and the target material is minimal, indicating good film-forming stability and compositional fidelity. These characteristics give this target material significant application advantages and long-term development potential in the display field, especially in the manufacture of high-end display devices with stringent performance requirements such as OLEDs and Micro-LEDs.

[0049] Example 1 exhibits the highest target resistivity primarily due to its lowest indium content; while its highest film transmittance is attributed to its highest germanium content.

[0050] Example 2 exhibits the highest carrier concentration, mainly because it contains the most tin ions among similar elemental dopants. When tin substitutes for indium, tin ions can introduce more carriers compared to other metal ions of the same valence.

[0051] Example 3 exhibits the smallest grain size, the most uniform grain structure, and the least elemental difference. Germanium is attributed to the addition of yttrium oxide. Through the pinning effect of yttrium between the crystal lattice, abnormal grain growth is restricted, and the uniformity of grains within the target material is improved. The uniformity of the target material grains is closely related to the uniformity of the thin film. Therefore, a smaller degree of segregation can be achieved, resulting in the smallest difference between the thin film elements and the target material elements.

[0052] Comparing Examples 4, 5, and 6, under the same ratio of indium, gallium, and germanium, Example 4 exhibited the highest mobility, Example 5 exhibited the highest carrier concentration, and Example 6 exhibited the highest film uniformity, thus confirming the effectiveness of zinc for high mobility, tin for high carrier concentration, and yttrium for high uniformity, respectively.

[0053] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and many other variations of different aspects of the invention as described above exist, which are not provided in detail for the sake of brevity. Any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A high-performance semiconductor oxide IGGXO target for the display industry, characterized in that, It includes: 50-80 at% indium oxide powder, 5-30 at% gallium oxide powder, 5-20 at% germanium oxide powder, 0.1-2 at% zinc oxide powder, 0.1-2 at% tin oxide powder, and 0.1-2 at% yttrium oxide powder.

2. The high-performance semiconductor oxide IGGXO target for the display field according to claim 1, characterized in that, It includes: 65-75 at% indium oxide powder, 5-20 at% gallium oxide powder, 5-15 at% germanium oxide powder, 0.5-1 at% zinc oxide powder, 0.5-1 at% tin oxide powder, and 0.5-1 at% yttrium oxide powder.

3. The high-performance semiconductor oxide IGGXO target for the display field according to claim 2, characterized in that, The indium oxide powder, gallium oxide powder, germanium oxide powder, zinc oxide powder, tin oxide powder, and yttrium oxide powder are all oxide powders with a purity of 99.99%.

4. The method of applying the high-performance semiconductor oxide IGGXO target material in the display field according to any one of claims 1-3, characterized in that, This includes thin film preparation methods: Step 1: Mix various oxide powders with anhydrous ethanol at a solid-liquid ratio of 1:1.5, and grind them in a ball mill for 4-6 hours to obtain a uniform slurry; Step 2, spray granulation: The slurry is centrifuged and spray granulated to obtain spherical particles; Step 3: The granulated powder is formed into an integral target blank by cold isostatic pressing; Step 4, Two-stage atmospheric pressure sintering: High-temperature densification stage: Increase the temperature to 1450-1500℃ at a rate of 5℃ / min and hold for 6-8 hours; Grain control stage: Cool down to 1350℃ and hold for 40-45 hours; Step 5: Precision machining, using diamond grinding wheels and chemical mechanical polishing to achieve a surface roughness Ra≤0.5μm and flatness ≤0.02mm / m for the target material; Step 6, Magnetron sputtering deposition: The system employs a medium-frequency magnetron sputtering system with a target-substrate distance of 60-80 mm, a working gas pressure of 0.5-1.0 Pa, an Ar:O2 ratio of 95:5, and a sputtering power density of 8-12 W / cm³. 2 Substrate temperature 200-300℃; Step Six, Post-processing: Rapid thermal annealing: In a N2 atmosphere, the temperature is increased to 400-450℃ at a rate of 20℃ / s and held for 30-60s to repair lattice defects during sputtering and improve carrier mobility to >50cm². 2 / (V·s).

5. The application method of the high-performance semiconductor oxide IGGXO target material in the display field according to claim 4, characterized in that, In step one, the ball mill speed is 300-400 rpm, and the ball-to-material ratio is 5:

1.

6. The application method of the high-performance semiconductor oxide IGGXO target material in the display field according to claim 4, characterized in that, In step two, the granulator inlet temperature is 200-220℃ and the outlet temperature is 80-90℃.

7. The application method of the high-performance semiconductor oxide IGGXO target material in the display field according to claim 4, characterized in that, The isostatic pressure in step three is 200-250 MPa, and the holding time is 5-10 minutes.

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