Transparent conductive film, preparation method thereof and photoelectric device

Abstract

The application discloses a transparent conductive film, a preparation method thereof and a photoelectric device. The transparent conductive film comprises a substrate, a first stack and a second stack which are periodically and laminatedly arranged on the substrate; wherein one of the first stack and the second stack comprises an IZO thin layer, and the other comprises an ITO thin layer. The application solves the problem of certain performance defects when a single film layer is used as the transparent conductive film in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a transparent conductive thin film, its preparation method, and an optoelectronic device. Background Technology

[0002] Transparent conductive films are a core component of modern optoelectronic devices, requiring excellent conductivity, high visible light transmittance, good processing performance, and environmental stability. They are widely used in displays, touch screens, photovoltaics, and LEDs. Currently, the most widely used transparent conductive film in industry is indium tin oxide (ITO) film, which has advantages such as high carrier concentration, low resistivity, and high visible light transmittance. However, it has significant drawbacks: ITO films have high crystallinity and relatively large surface roughness, which can adversely affect subsequent device fabrication; wet etching is slow, residues are easily generated during the etching process, and the etching solution can easily damage the underlying film, leading to reduced device yield; crystallization distortion is prone to occur at high temperatures, resulting in poor thermal stability, which limits its application in high-temperature fabrication processes and flexible devices.

[0003] Indium zinc oxide (IZO) thin film, as a novel amorphous transparent conductive film, has advantages such as smooth surface, excellent wet etching performance, and good adaptability to low-temperature deposition. It can effectively solve the etching and surface roughness problems of ITO thin film. However, IZO thin film has a low carrier concentration, high resistivity, poor water vapor barrier properties, and poor acid and alkali stability. Long-term use can easily lead to performance degradation, making it difficult to meet the long-term stable operation requirements of high-performance devices.

[0004] Therefore, both indium zinc oxide (IZO) films and indium tin oxide (ITO) films currently have certain performance defects as transparent conductive films. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a transparent conductive film, its preparation method, and an optoelectronic device, aiming to solve the problem of certain performance defects in the existing transparent conductive films.

[0006] The embodiments of the present invention are implemented as follows: On one hand, embodiments of the present invention provide a transparent conductive film, comprising a substrate, a first stack and a second stack periodically stacked on the substrate; One of the first stack and the second stack includes an IZO thin layer, and the other includes an ITO thin layer.

[0007] In addition, the transparent conductive film proposed above can also have at least the following additional technical features: Furthermore, the thickness of the transparent conductive film is 30nm to 150nm; Within a single cycle, the thickness of the IZO thin layer is 3nm to 20nm, and the thickness of the ITO thin layer is 3nm to 20nm.

[0008] Furthermore, the growth cycle of the first and second stacks is 2 to 10.

[0009] Furthermore, the substrate material includes any one of glass, polyethylene terephthalate, polyimide, sapphire, or semiconductor wafer.

[0010] Furthermore, the transparent conductive film also includes a protective layer disposed on the last second stack; The protective layer includes SiO x The protective layer has a thickness of 1 nm to 5 nm.

[0011] On the other hand, embodiments of the present invention provide a method for preparing a transparent conductive film, used to prepare the transparent conductive film described in any one of the above-mentioned methods, the method comprising: Provide a substrate and pretreat the substrate; The pretreated substrate is placed in the magnetron sputtering deposition chamber, and the environment of the magnetron sputtering deposition chamber is controlled to bring the environment of the magnetron sputtering deposition chamber to a preset state. Using the corresponding target material, a preset power is applied to deposit the first layer on the substrate. After vacuum purification, the target material is switched to the corresponding target material, and a preset power is applied to deposit the second layer on the first layer. The deposition of the first and second layers is repeated a predetermined number of times to form a periodic alternating stacked structure, resulting in a transparent conductive film. One of the first and second stacks includes an IZO thin layer, and the other includes an ITO thin layer.

[0012] Furthermore, in the above-mentioned method for preparing transparent conductive films, the single-layer deposition rate of both the IZO thin layer and the ITO thin layer is controlled to be 0.05 nm / s to 0.2 nm / s.

[0013] Furthermore, in the above-mentioned method for preparing the transparent conductive film, the power applied during the deposition of the IZO thin layer is 60W to 120W RF power, and the power applied during the deposition of the ITO thin layer is 80W to 150W DC or RF power.

[0014] Furthermore, in the above-mentioned method for preparing transparent conductive films, the deposition temperature of both the first and second layers is controlled to be between 20°C and 100°C.

[0015] In another aspect, embodiments of the present invention provide an optoelectronic device comprising the aforementioned transparent conductive film.

[0016] Compared with the prior art, the embodiments of the present invention have at least the following beneficial effects: This invention employs an alternating stacked design of IZO and ITO thin layers to form an amorphous / microcrystalline multilayer composite structure, rather than the existing simple double-layer stack. This alternating stack structure synergistically optimizes the advantages of the two materials, avoiding the problems of high crystallinity and large surface roughness of ITO films, which can adversely affect subsequent device fabrication, and the problems of low carrier concentration, high resistivity, and poor water vapor barrier and acid-base stability of IZO films. At the same time, it solves the performance shortcomings of single IZO and ITO thin layers, achieving a synergistic improvement in optoelectronic performance, etching performance, surface morphology, and environmental stability. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for preparing a transparent conductive film according to an embodiment of the present invention; Figure 2 Transmittance curves of transparent conductive films with a thickness of 64 nm prepared for different thin film materials; Figure 3 Transmittance curves of transparent conductive films with a thickness of 100 nm prepared for different thin film materials; The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0019] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] The purpose of this invention is to provide a transparent conductive thin film with alternating IZO and ITO deposition and its preparation method. By designing an IZO / ITO nanoscale alternating stacked structure and combining it with precise deposition parameter control, the performance defects of single ITO films and single IZO films are solved, achieving a synergistic improvement in photoelectric performance, etching performance, surface morphology, and environmental stability. Simultaneously, it is compatible with existing industrial production lines, reducing preparation costs and improving device yield and lifespan. Please see Figure 1 The diagram shows a flowchart of a transparent conductive film preparation method proposed in an embodiment of the present invention, which includes steps S10 to S13.

[0022] Step S10: Provide a substrate and preprocess the substrate.

[0023] The substrate is ultrasonically cleaned sequentially with acetone, ethanol, and deionized water for 10 to 15 minutes each to remove oil, organic impurities, and inorganic impurities from the substrate surface, respectively. After cleaning, it is dried with nitrogen and then baked in a vacuum environment at 80°C to 120°C for 30 minutes to remove residual moisture from the substrate surface and prevent moisture from affecting the deposition quality and interlayer bonding.

[0024] Step S11: Place the pretreated substrate into the magnetron sputtering deposition chamber and adjust the environment of the magnetron sputtering deposition chamber to a preset state.

[0025] The pretreated substrate is placed in the magnetron sputtering deposition chamber, and the chamber is evacuated to a vacuum level ≤ 5 × 10⁻⁶. -4 Pa ensures that there is no interference from impurity gases in the chamber; Ar gas with a purity of 99.999% is introduced as the working gas, and the working gas pressure in the chamber is adjusted to 0.3 Pa to 0.8 Pa to stabilize the sputtering environment and ensure the deposition rate and film uniformity.

[0026] Step S12: Using the corresponding target material, apply a preset power to deposit the first layer on the substrate. After vacuum purification, switch to the corresponding target material and apply a preset power to deposit the second layer on the first layer.

[0027] In this configuration, one of the first and second stacks includes an IZO thin layer, and the other includes an ITO thin layer. For example, when the first stack includes an IZO thin layer and the second stack includes an ITO thin layer, an IZO target (In₂O₃:ZnO = 90:10wt%) is used, and an RF power of 60W–120W is applied to deposit an IZO thin layer 3nm–20nm thick on the substrate to obtain the first stack. Subsequently, the chamber is evacuated and purified to ≤1×10⁻⁶. -3 Pa, thoroughly remove residual target particles and gaseous impurities in the chamber to avoid interlayer cross-contamination; switch to ITO target (In2O3:SnO2= 90:10 wt%), apply DC or RF power of 80W to 150W, and deposit a 3nm to 20nm thick ITO thin layer on the IZO thin layer to obtain the second stack.

[0028] In practice, the deposition temperatures of the first and second layers are controlled between 20°C and 100°C, which falls within the low-temperature deposition range. This avoids damage to flexible substrates such as PET (polyethylene terephthalate) and PI (polyimide) caused by high temperatures, while also inhibiting excessive grain growth, ensuring the amorphous / microcrystalline structure of the film, and improving surface smoothness and etching performance. The single-layer deposition rates of the IZO and ITO thin layers are controlled between 0.05 nm / s and 0.2 nm / s to ensure uniform and dense film thickness, reduce internal porosity and defects, and improve interlayer bonding and photoelectric properties. During interlayer switching, the vacuum purification time is controlled between 10 and 30 seconds, which can thoroughly remove residual impurities in the chamber while avoiding a decrease in preparation efficiency due to excessive purification time.

[0029] Step S13: Repeat the deposition of the first and second layers a preset number of times to form a periodic alternating stacked structure to obtain a transparent conductive film.

[0030] Specifically, the deposition steps of IZO thin layer and ITO thin layer are repeated n times to form an alternating stacked structure of n cycles, and finally a transparent conductive layer is obtained.

[0031] Furthermore, in some optional embodiments of the present invention, the substrate with the deposited alternating layered structure can be placed in an N2 atmosphere and annealed at a temperature of 150°C to 200°C for 30 min. Low-temperature annealing eliminates internal defects in the film, further reduces resistivity, and improves the crystal integrity and stability of the film.

[0032] In addition, the present invention also proposes a transparent conductive film, comprising a substrate, a first stack and a second stack periodically stacked on the substrate; One of the first and second stacks includes an IZO thin layer, and the other includes an ITO thin layer.

[0033] In specific implementations, the first stack may include an IZO thin layer, and the second stack may include an ITO thin layer. When the first stack includes an ITO thin layer and the second stack includes an IZO thin layer, the thickness of the transparent conductive film is 30 nm to 150 nm. Within a single cycle, the thickness of the IZO thin layer is 3 nm to 20 nm, and the thickness of the ITO thin layer is 3 nm to 20 nm. The growth cycle between the first and second stacks is 2 to 10. The transparent conductive film has a sheet resistivity ≤ 200 Ohm / sq., a visible light transmittance ≥ 80%, and a surface roughness Ra ≤ 0.5 nm.

[0034] Furthermore, to optimize performance balance, the period value is preferably 3 to 5, and the thickness of both the IZO thin layer and the ITO thin layer is preferably 5 nm to 10 nm. At this time, the photoelectric performance, etching performance and stability of the film achieve the best synergistic effect, while avoiding the increase in preparation cost and process complexity caused by too many periods.

[0035] The multilayer stacked structure is amorphous or microcrystalline. By controlling the deposition parameters to suppress excessive grain growth, the surface roughness of the film can be effectively reduced, the wet etching performance can be improved, and the problem of decreased thermal stability caused by the crystalline structure can be avoided.

[0036] In addition, the outermost layer of the multilayer stacked structure can be an IZO thin layer or an ITO thin layer, or a 1nm to 5nm thick SiO2 layer can be covered on the outermost layer, depending on the actual application requirements. x Protective layer, SiO x The protective layer can further enhance the water vapor barrier properties and chemical stability of the thin film, and extend the service life of the device.

[0037] The substrate can be glass, PET (polyethylene terephthalate), PI (polyimide), sapphire or semiconductor wafers to suit different application scenarios. In particular, flexible substrates such as PET and PI can meet the needs of flexible devices such as flexible displays and flexible photovoltaics.

[0038] On the other hand, embodiments of the present invention also propose an optoelectronic device comprising the above-mentioned transparent conductive film.

[0039] Among them, optoelectronic devices include at least products that require transparent conductive films, such as display devices, touch panels, LED devices, and photovoltaic modules.

[0040] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0041] Example 1 Embodiment 1 of the present invention provides a method for preparing a transparent conductive film, comprising: 1) Substrate pretreatment: The PET substrate was ultrasonically cleaned with acetone, ethanol and deionized water for 12 min each, dried with nitrogen, and then vacuum baked at 100℃ for 30 min. 2) Vacuum and Atmosphere Control: Place the PET substrate into the deposition chamber and evacuate to a background vacuum of 3×10⁻⁶. -4 Pa, introduce 99.999% Ar gas, and adjust the working gas pressure to 0.5 Pa; 3) Alternating sputtering deposition: Using an IZO target (In₂O₃:ZnO = 90:10 wt%), with an RF power of 90 W and a deposition rate of 0.1 nm / s, an 8 nm thick IZO layer was deposited; the layer was then vacuum-purified to 8 × 10⁻⁶ wt%. -4 Pa, purification time 20 s; switch to ITO target (In2O3:SnO2=90:10 wt%), RF power 120 W, deposition rate 0.1 nm / s, deposit 8 nm thick ITO thin layer; repeat the above steps 4 times to form 4 cycles of alternating stacks; 4) Post-treatment: Anneal at 180℃ for 30 min under N2 atmosphere to obtain a transparent conductive film.

[0042] Example 2 Embodiment 2 of the present invention also proposes a method for preparing a transparent conductive film, comprising: 1) Substrate pretreatment: The glass substrate was ultrasonically cleaned with acetone, ethanol and deionized water for 15 min each, dried with nitrogen and then vacuum baked at 120℃ for 30 min. 2) Vacuum and Atmosphere Control: Place the glass substrate into the deposition chamber and evacuate to a background vacuum of 1×10⁻⁶. -4 Pa, introduce 99.999% Ar gas, and adjust the working gas pressure to 0.8 Pa; 3) Alternating sputtering deposition: Using an IZO target (In₂O₃:ZnO = 90:10 wt%), RF power 120 W, deposition rate 0.2 nm / s, a 10 nm thick IZO layer was deposited; vacuum purification to 5 × 10⁻⁶ ppm. -4 Pa, purification time 30 s; switch to ITO target (In2O3:SnO2=90:10 wt%), DC power 150 W, deposition rate 0.2 nm / s, deposit 10 nm thick ITO thin layer; repeat the above steps 5 times to form 5 cycles of alternating stacks; 4) Post-treatment: Anneal at 200℃ for 30 min under N2 atmosphere to obtain a transparent conductive film.

[0043] Example 3 Embodiment 3 of the present invention also proposes a method for preparing a transparent conductive film. The difference between the method for preparing the transparent conductive film in this embodiment and the method for preparing the transparent conductive film in Embodiment 1 is that: The transparent conductive film uses 64nm ITO.

[0044] Example 4 Embodiment 4 of the present invention also proposes a method for preparing a transparent conductive film. The difference between the method for preparing the transparent conductive film in this embodiment and the method for preparing the transparent conductive film in Embodiment 1 is that: The transparent conductive film uses 64nm IZO.

[0045] Example 5 Embodiment 5 of the present invention also proposes a method for preparing a transparent conductive film. The difference between the method for preparing the transparent conductive film in this embodiment and the method for preparing the transparent conductive film in Embodiment 1 is that: The transparent conductive film uses 100nm ITO.

[0046] Example 6 Embodiment Six of the present invention also proposes a method for preparing a transparent conductive film. The difference between the method for preparing the transparent conductive film in this embodiment and the method for preparing the transparent conductive film in Embodiment One is that: The transparent conductive film uses 100nm IZO.

[0047] Please refer to Table 1 below, which shows the performance test data of the transparent conductive films prepared in Examples 1 to 6 of the present invention.

[0048] Table 1

[0049] Additionally, please see Figures 2 to 3 Table 1 and the figures show the transmittance data for transparent conductive films of different thicknesses. Combining the data in Table 1 and the figures, it is clear that the performance of the transparent conductive film prepared in this embodiment of the invention has been effectively improved.

[0050] In summary, the transparent conductive film proposed in the embodiments of the present invention has at least the following beneficial effects: 1) Excellent optoelectronic performance: Through the alternating nanoscale stacking design of IZO and ITO, the carrier concentration and mobility are synergistically optimized, resulting in a film surface resistance of ≤200 Ohm / Sq., which is better than that of a single IZO film; the visible light transmittance is ≥80%, which is comparable to that of a single ITO film, and can meet the optoelectronic requirements of high-end optoelectronic devices.

[0051] 2) Excellent etching performance: The alternating stacked structure is mainly amorphous / microcrystalline, with low surface roughness (Ra≤0.5nm), wet etching rate ≥5 nm / s, no etching residue, no damage to the underlying film, which can significantly improve the device fabrication yield and reduce processing costs.

[0052] 3) Outstanding stability: The alternating structure of IZO and ITO thin films can compensate for the stability defects of single materials. The thermal stability (no significant degradation at 250℃), water vapor barrier and chemical stability of the thin film are significantly better than those of single IZO thin film, thus extending the service life of the device.

[0053] 4) Strong process compatibility: It adopts a low-temperature (room temperature to 100℃) magnetron sputtering process, which is compatible with various substrates such as glass, PET, and PI, and is especially suitable for the fabrication of flexible devices; the process steps are simple and highly controllable, and can be directly connected to existing industrial production lines without large-scale equipment modification, resulting in low manufacturing costs.

[0054] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A transparent conductive film, characterized in that, It includes a substrate, a first stack and a second stack periodically stacked on the substrate; One of the first stack and the second stack includes an IZO thin layer, and the other includes an ITO thin layer.

2. The transparent conductive film according to claim 1, characterized in that, The thickness of the transparent conductive film is 30nm to 150nm; Within a single cycle, the thickness of the IZO thin layer is 3nm to 20nm, and the thickness of the ITO thin layer is 3nm to 20nm.

3. The transparent conductive film according to claim 1, characterized in that, The growth cycle of the first and second stacks is 2 to 10.

4. The transparent conductive film according to claim 1, characterized in that, The substrate material includes any one of glass, polyethylene terephthalate, polyimide, sapphire, or semiconductor wafer.

5. The transparent conductive film according to any one of claims 1 to 4, characterized in that, The transparent conductive film also includes a protective layer disposed on the last second stack; The protective layer includes SiO x The protective layer has a thickness of 1 nm to 5 nm.

6. A method for preparing a transparent conductive thin film, characterized in that, The method for preparing the transparent conductive film according to any one of claims 1 to 5 comprises: Provide a substrate and pretreat the substrate; The pretreated substrate is placed in the magnetron sputtering deposition chamber, and the environment of the magnetron sputtering deposition chamber is controlled to bring the environment of the magnetron sputtering deposition chamber to a preset state. Using the corresponding target material, a preset power is applied to deposit the first layer on the substrate. After vacuum purification, the target material is switched to the corresponding target material, and a preset power is applied to deposit the second layer on the first layer. The deposition of the first and second layers is repeated a predetermined number of times to form a periodic alternating stacked structure, resulting in a transparent conductive film. One of the first and second stacks includes an IZO thin layer, and the other includes an ITO thin layer.

7. The method for preparing a transparent conductive thin film according to claim 6, characterized in that, The single-layer deposition rate of both the IZO thin layer and the ITO thin layer was controlled to be 0.05 nm / s to 0.2 nm / s.

8. The method for preparing a transparent conductive thin film according to claim 6, characterized in that, The power applied during the deposition of the IZO thin layer is 60 W to 120 W of RF power, and the power applied during the deposition of the ITO thin layer is 80 W to 150 W of DC or RF power.

9. The method for preparing a transparent conductive thin film according to claim 6, characterized in that, The deposition temperatures of both the first and second layers were controlled to be between 20°C and 100°C.

10. An optoelectronic device, characterized in that, Includes the transparent conductive film according to any one of claims 1 to 5.

Images