Aluminum oxide and silicon oxide alternate deposition multilayer film, preparation method and application thereof
By using mid-frequency magnetron sputtering technology to alternately deposit alumina and silicon oxide layers, the problems of target poisoning and target surface arcing in the preparation process of oxide thin films are solved, achieving high density and corrosion resistance, which is suitable for optical thin films and corrosion protection of optoelectronic devices.
Patent Information
- Application Number
- CN202510971669.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-10-28
AI Technical Summary
Existing oxide films suffer from target poisoning and target surface arcing during the preparation process, resulting in poor film quality and performance. At the same time, the pores are easily permeated, affecting their adaptability and durability in marine environments.
By employing mid-frequency magnetron sputtering technology, alternating layers of alumina and silicon oxide are deposited to form an amorphous, short-range ordered, long-range disordered multilayer alumina-silicon oxide film. By controlling the film thickness and deposition parameters, target poisoning and target surface arcing are avoided, thereby improving the film density.
It has achieved a highly dense and corrosion-resistant oxide film with excellent optical and corrosion barrier properties, suitable for large-area production, applicable to optical films and corrosion protection for optoelectronic devices, and is environmentally friendly and highly efficient in production.
Smart Images
Figure CN120844016A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of surface protection technology, specifically to a method for preparing a multilayer thin film with alternating deposition of alumina and silicon oxide, and its application. Background Technology
[0002] Alumina and silicon dioxide are inorganic oxide materials that possess excellent high-temperature resistance, corrosion resistance, and optical transmittance. Furthermore, they exhibit high dielectric constants, chemical stability, and high transparency to specific electromagnetic wave bands, making them key components in precision optoelectronic devices such as flat panel displays and lasers, enhancing device performance and reliability. By effectively combining these two materials, the prepared Al₂O₃ / SiO₂ thin films hold promise for demonstrating unique advantages in the field of electronic device protection. However, achieving controllable preparation and performance optimization of these films remains a challenge for current research.
[0003] Currently, oxide thin films can be prepared using methods such as anodic oxidation, chemical vapor deposition (CVD), and physical vapor deposition (PVD). Anodizing is prone to environmental pollution and is unsuitable for substrates with poor conductivity. CVD easily introduces organic pollutants and also poses some environmental risks. PVD, on the other hand, offers advantages such as minimal environmental pollution, strong adhesion, and the ability to achieve large-area deposition. Magnetron sputtering, a widely used PVD technique, boasts advantages like fast deposition speed, low deposition temperature, and applicability to all substrate materials. It has been increasingly applied to the preparation and development of oxide thin films. Utilizing a metallic target and introducing reactive gases allows for control of film thickness at the micro-nano scale, enabling its use as optical thin films for optoelectronic devices or corrosion protection films, demonstrating immense application potential. However, traditional DC magnetron sputtering of oxides often suffers from target poisoning and arcing, affecting the quality and performance of the final film. Mid-frequency magnetron sputtering effectively avoids these problems in oxide deposition, making it a highly efficient and environmentally friendly method that has gradually become a research hotspot. Traditional oxide films are prone to failure due to their porous structure, which makes them susceptible to permeation. As a result, their adaptability and durability in marine environments urgently need to be addressed.
[0004] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention
[0005] The purpose of this invention is to solve the problem of how to prepare oxide thin films with high density, high corrosion resistance and optical properties, and to provide a method for preparing multilayer thin films with alternating deposition of alumina and silicon oxide, and its application.
[0006] To achieve the above objectives, the present invention discloses a multilayer thin film with alternating deposition of alumina and silicon oxide. The thin film includes an alumina layer and a silicon oxide layer sequentially from the metal substrate to the surface. The thickness ratio of the alumina layer to the silicon oxide layer is 2:1, and the total thickness of the thin film is 1300-1500 nm.
[0007] Both the alumina layer and the silicon oxide layer are amorphous short-range ordered and long-range disordered structures, and the metal substrate is any one of pure copper, cemented carbide, stainless steel, and copper alloy materials.
[0008] This invention also discloses a method for preparing the above-mentioned alternating deposition of alumina and silicon oxide multilayer thin films, comprising the following steps:
[0009] S1. Grind the metal substrate with SiC sandpaper in sequence, and then polish it with polishing paste until it is mirror smooth.
[0010] S2, the metal substrate polished in step S1 is ultrasonically cleaned with anhydrous ethanol and deionized water for 20-30 minutes, and then dried with dry nitrogen gas for later use.
[0011] S3. Fix the metal substrate dried in step S2 onto the sample holder of the magnetron sputtering device. After the chamber is evacuated, argon gas is introduced to perform argon ion etching for 5 to 10 minutes.
[0012] S4. After the argon ion etching in step S3 is completed, argon gas is introduced to perform sputter cleaning of Al and Si targets.
[0013] S5. After the target washing in step S4 is completed, argon and oxygen are introduced, the Al target is opened, and an Al2O3 layer is sputtered and deposited.
[0014] S6. After the Al2O3 layer is deposited in step S5, argon and oxygen are introduced, the Si target is turned on, and the SiO2 layer is sputtered and deposited.
[0015] S7. Repeat steps S5 and S6, alternatingly depositing Al2O3 and SiO2 layers until the desired thin film is obtained.
[0016] In step S1, the metal substrate is polished sequentially with SiC sandpaper of different grit numbers, namely 600#, 800#, 1000#, 1500#, and 2000#, and the polishing paste is W2.5.
[0017] In step S3, the vacuum is evacuated to 3×10⁻⁶. -3 Pa, the amount of argon gas introduced is 120-150 sccm, the working pressure is 1.0-1.5 Pa, and the substrate bias voltage is set to -800-1000 V.
[0018] In step S4, the amount of argon gas introduced is 35-45 sccm, the working pressure is 0.3-0.5 Pa, the target sputtering current is set to 3-5 A, and the target washing time is 20-40 min.
[0019] In step S5, the argon gas flow rate is 35-45 sccm, the oxygen gas flow rate is 4-6 sccm, the working pressure is 0.3-0.5 Pa, the Al target sputtering current is set to 1.5-3 A, and the deposition time is 180-200 min.
[0020] In step S6, the argon gas flow rate is 35-45 sccm, the oxygen gas flow rate is 10-15 sccm, the working pressure is 0.3-0.5 Pa, the Si target sputtering current is set to 3-5 A, and the deposition time is 20-40 min.
[0021] In step S7, the Al2O3 layer and the SiO2 layer are deposited alternately for 1 to 3 cycles.
[0022] The present invention also discloses the application of the above-mentioned alternating deposition of alumina and silicon oxide multilayer thin films in the field of electronic device protection.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] 1. The present invention proposes an alternating deposition of silicon oxide and aluminum oxide multilayer thin films, incorporating the concept of multilayer interface design. The formation of oxide film is promoted under the introduction of an appropriate amount of oxygen. Multilayer composite thin films are obtained by alternating deposition of metal oxides and non-metal oxides. Due to the presence of amorphous oxides and the multilayer interface effect, the film has high density. The barrier effect of the interface inhibits the extension of film defects. While maintaining the high transmittance of the oxide itself, the corrosion barrier performance of the film is further improved.
[0025] 2. The method for preparing multilayer thin films by alternating deposition of silicon oxide and aluminum oxide in this invention uses medium-frequency reactive magnetron sputtering twin target deposition, which avoids the problems of low uniformity and poor film quality caused by DC sputtering. The preparation process is simple, does not produce toxic or harmful substances, is green and environmentally friendly, has high production efficiency, is suitable for large-area production, and is easy to realize industrial application and promotion. The multilayer composite thin film in this invention can be used in the field of surface protection of optoelectronic components. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the alternating deposition of alumina and silicon dioxide multilayer thin film structure of the present invention;
[0027] Figure 2 This is a SEM image of the thin film in Example 1 of this invention;
[0028] Figure 3This is a SEM image of the thin film in Example 2 of this invention;
[0029] Figure 4 This is a SEM image of the thin film in Example 3 of this invention;
[0030] Figure 5 This is a TEM image of the thin film in Example 3 of this invention;
[0031] Figure 6 These are the HRTEM and SAED images of the thin film in Example 3 of this invention;
[0032] Figure 7 This is a SEM image of the thin film in Comparative Example 1 of this invention;
[0033] Figure 8 This is a SEM image of the thin film in Comparative Example 2 of this invention;
[0034] Figure 9 The wavelength transmittance curves of Examples 1-3 and Comparative Examples 1 and 2 in this invention are shown.
[0035] Figure 10 The potentiodynamic polarization curves of Examples 1-3 and Comparative Examples 1 and 2 in this invention are shown.
[0036] Figure 11 The corrosion current and corrosion potential are those of Examples 1-3 and Comparative Examples 1 and 2 in this invention.
[0037] The numbers in the image represent:
[0038] 1-Metal matrix; 2, 4, 6-Al2O3 layers; 3, 5, 7-SiO2 layers. Detailed Implementation
[0039] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.
[0040] Example 1
[0041] A multilayer thin film with alternating deposition of silicon oxide and aluminum oxide is disclosed. The thin film comprises an aluminum oxide layer and a silicon oxide layer sequentially from the metal substrate to the surface. In this embodiment, Al and Si targets are used to alternately deposit one cycle of silicon oxide and aluminum oxide thin film on the metal substrate. The specific preparation steps are as follows:
[0042] S1: First, polish the metal substrate with SiC sandpaper of different grits (600#, 800#, 1000#, 1500#, 2000#) in sequence, and then polish it with polishing paste (W2.5) until it is mirror smooth.
[0043] S2: The metal substrate is ultrasonically cleaned with anhydrous ethanol and deionized water for 30 minutes in sequence, and then dried with dry nitrogen gas for later use.
[0044] S3: Fix the metal substrate onto the sample holder of the magnetron sputtering device, and evacuate the chamber to 3×10⁻⁶. -3 After Pa, 120 sccm of argon gas was introduced, the working pressure was 1.0 Pa, the substrate bias voltage was set to -800 V, and argon ion etching was performed for 5 min.
[0045] S4: After argon ion etching is completed, 40 sccm of argon gas is introduced, the working pressure is 0.4 Pa, the target sputtering current is set to 3 A, and sputter cleaning of the Al target is performed for 20 min.
[0046] S5: After the target is washed, 40 sccm of argon gas and 5 sccm of oxygen gas are introduced, with a working pressure of 0.4 Pa. The Al target sputtering current is set to 3 A, and an Al2O3 layer is sputtered and deposited for 16 hours. Finally, the thin film sample is removed after the furnace has cooled completely.
[0047] S6: After the Al2O3 layer is deposited, 40 sccm of argon gas and 10 sccm of oxygen gas are introduced. The working pressure is 0.4 Pa. The Si target sputtering current is set to 5 A, and the SiO2 layer is sputtered and deposited for 23 min. Finally, the thin film sample is removed after the furnace has cooled completely.
[0048] The prepared film has a thickness of 1.45 μm. Figure 2 The thin film has a typical amorphous structure; the average transmittance in the visible light band is 92.35%. Figure 9 The corrosion current density is 4.40 × 10⁻⁶. -8 A / cm 2 ( Figure 11 The corrosion potential is -239.46mV. Figure 11 ).
[0049] Example 2
[0050] A multilayer thin film with alternating deposition of silicon oxide and aluminum oxide is disclosed. The thin film comprises an aluminum oxide layer and a silicon oxide layer sequentially from the metal substrate to the surface. In this embodiment, Al and Si targets are used to alternately deposit two cycles of silicon oxide and aluminum oxide thin films on the metal substrate. The specific preparation steps are as follows:
[0051] S1: First, polish the metal substrate with SiC sandpaper of different grits (600#, 800#, 1000#, 1500#, 2000#) in sequence, and then polish it with polishing paste (W2.5) until it is mirror smooth.
[0052] S2: The metal substrate is ultrasonically cleaned with anhydrous ethanol and deionized water for 30 minutes in sequence, and then dried with dry nitrogen gas for later use.
[0053] S3: Fix the metal substrate onto the sample holder of the magnetron sputtering device, and evacuate the chamber to 3×10⁻⁶. -3 After Pa, 120 sccm of argon gas was introduced, the working pressure was 1.0 Pa, the substrate bias voltage was set to -800 V, and argon ion etching was performed for 5 min.
[0054] S4: After argon ion etching is completed, 40 sccm of argon gas is introduced, the working pressure is 0.4 Pa, the target sputtering current is set to 3 A, and sputter cleaning of the Al target is performed for 20 min.
[0055] S5: After the target is washed, 40 sccm of argon gas and 5 sccm of oxygen gas are introduced, with a working pressure of 0.4 Pa. The Al target sputtering current is set to 3 A, and an Al2O3 layer is sputtered and deposited for 16 hours. Finally, the thin film sample is removed after the furnace has cooled completely.
[0056] S6: After the Al2O3 layer is deposited, 40 sccm of argon gas and 10 sccm of oxygen gas are introduced. The working pressure is 0.4 Pa. The Si target sputtering current is set to 5 A. The SiO2 layer is sputtered and deposited for 23 min.
[0057] S7: Repeat steps S5 and S6 above, alternating between depositing Al2O3 and SiO2 layers until a composite film with two cycles is obtained. Finally, remove the film sample after sufficient furnace cooling.
[0058] The prepared film has a thickness of 1.46 μm. Figure 3 The thin film has a typical amorphous structure; the average transmittance in the visible light band is 91.64%. Figure 9 The corrosion current density is 2.08 × 10⁻⁶. -8 A / cm 2 ( Figure 11 The corrosion potential is -234.55mV. Figure 11 ).
[0059] Example 3
[0060] like Figure 1 As shown, a multilayer thin film with alternating deposition of silicon oxide and aluminum oxide is described. The thin film includes an aluminum oxide layer and a silicon oxide layer sequentially from the metal substrate to the surface. In this embodiment, Al and Si targets are used to alternately deposit three cycles of silicon oxide and aluminum oxide thin films on the metal substrate. The specific preparation steps are as follows:
[0061] S1: First, polish the metal substrate with SiC sandpaper of different grits (600#, 800#, 1000#, 1500#, 2000#) in sequence, and then polish it with polishing paste (W2.5) until it is mirror smooth.
[0062] S2: The metal substrate is ultrasonically cleaned with anhydrous ethanol and deionized water for 30 minutes in sequence, and then dried with dry nitrogen gas for later use.
[0063] S3: Fix the metal substrate onto the sample holder of the magnetron sputtering device, and evacuate the chamber to 3×10⁻⁶. -3 After Pa, 120 sccm of argon gas was introduced, the working pressure was 1.0 Pa, the substrate bias voltage was set to -800 V, and argon ion etching was performed for 5 min.
[0064] S4: After argon ion etching is completed, 40 sccm of argon gas is introduced, the working pressure is 0.4 Pa, the target sputtering current is set to 3 A, and sputtering cleaning of Al and Si targets is performed for 20 min.
[0065] S5: After the target washing is completed, 40 sccm of argon gas and 5 sccm of oxygen gas are introduced. The working pressure is 0.4 Pa. The Al target sputtering current is set to 3 A. The Al2O3 layer is sputtered and deposited (2) for 3 h 10 min.
[0066] S6: After the Al2O3 layer is deposited, 40 sccm of argon gas and 10 sccm of oxygen gas are introduced. The working pressure is 0.4 Pa. The sputtering current of the Si target is set to 5 A. The SiO2 layer is sputtered and deposited (3) for 23 min.
[0067] S7: Repeat steps S5 and S6 above, alternatingly depositing Al2O3 layers (2, 4, 6) and SiO2 layers (3, 5, 7) until a composite film with 3 cycles is obtained. Finally, remove the film sample after it has been fully cooled in the furnace.
[0068] The total thickness of the prepared film is 1.43 μm. Figure 4 The Al2O3 layer to SiO2 layer thickness ratio is 2:1; SAED ( Figure 6 The thin film is characterized by all layers being amorphous. The average transmittance in the visible light band is 91.74%. Figure 9 The corrosion current density is 1.23 × 10⁻⁶. -8 A / cm 2 ( Figure 11 The corrosion potential is -227.07mV. Figure 11 ).
[0069] Figure 5The image shown is a TEM cross-sectional view of Example 1, in which the thin film exhibits a distinct periodic layered stacking characteristic.
[0070] Figure 6 The images shown are HRTEM images and corresponding SAED images of the Al2O3 and SiO2 layers in Example 1, both of which exhibit typical amorphous dispersed rings.
[0071] Comparative Example 1
[0072] In this comparative example, elemental Al metal target was used to deposit a single layer of Al2O3 film on a metal substrate. The specific preparation steps are as follows:
[0073] S1: First, polish the metal substrate with SiC sandpaper of different grits (600#, 800#, 1000#, 1500#, 2000#) in sequence, and then polish it with polishing paste (W2.5) until it is mirror smooth.
[0074] S2: The metal substrate is ultrasonically cleaned with anhydrous ethanol and deionized water for 30 minutes in sequence, and then dried with dry nitrogen gas for later use.
[0075] S3: Fix the metal substrate onto the sample holder of the magnetron sputtering device, and evacuate the chamber to 3×10⁻⁶. -3 After Pa, 120 sccm of argon gas was introduced, the working pressure was 1.0 Pa, the substrate bias voltage was set to -800 V, and argon ion etching was performed for 5 min.
[0076] S4: After argon ion etching is completed, 40 sccm of argon gas is introduced, the working pressure is 0.4 Pa, the target sputtering current is set to 3 A, and sputter cleaning of the Al target is performed for 20 min.
[0077] S5: After the target is washed, 40 sccm of argon gas and 5 sccm of oxygen gas are introduced, with a working pressure of 0.4 Pa. The Al target sputtering current is set to 3 A, and an Al2O3 layer is sputtered and deposited for 16 hours. Finally, the thin film sample is removed after the furnace has cooled completely.
[0078] The prepared film has a thickness of 1.43 μm. Figure 7 The thin film has a typical amorphous structure; the average transmittance in the visible light band is 91.61%. Figure 9 The corrosion current density is 5.73 × 10⁻⁶. -7 A / cm 2 ( Figure 11 The corrosion potential is -257.67mV. Figure 11 ).
[0079] Comparative Example 2
[0080] In this comparative example, elemental Si non-metallic target material was used to deposit a monolayer SiO2 thin film on a metal substrate. The specific preparation steps are as follows:
[0081] S1: First, polish the metal substrate with SiC sandpaper of different grits (600#, 800#, 1000#, 1500#, 2000#) in sequence, and then polish it with polishing paste (W2.5) until it is mirror smooth.
[0082] S2: The metal substrate is ultrasonically cleaned with anhydrous ethanol and deionized water for 30 minutes in sequence, and then dried with dry nitrogen gas for later use.
[0083] S3: Fix the metal substrate onto the sample holder of the magnetron sputtering device, and evacuate the chamber to 3×10⁻⁶. -3 After Pa, 120 sccm of argon gas was introduced, the working pressure was 1.0 Pa, the substrate bias voltage was set to -800 V, and argon ion etching was performed for 5 min.
[0084] S4: After argon ion etching is completed, 40 sccm of argon gas is introduced, the working pressure is 0.4 Pa, the target sputtering current is set to 3 A, and the Si target is sputtered and cleaned for 20 min.
[0085] S5: After the target is washed, 40 sccm of argon gas and 10 sccm of oxygen gas are introduced. The Si target sputtering current is set to 5A, and a SiO2 layer is sputtered and deposited for 2 hours and 50 minutes. Finally, the thin film sample is removed after the furnace has cooled completely.
[0086] The prepared film has a thickness of 1.43 μm. Figure 8 The thin film has a typical amorphous structure; the average transmittance in the visible light band is 91.55%. Figure 9 The corrosion current density is 5.85 × 10⁻⁶. -7 A / cm 2 ( Figure 11 The corrosion potential is -233.04 mV. Figure 11 ).
[0087] The thin film samples obtained in Comparative Examples 1-3 and Comparative Examples 1 and 2 were tested as follows:
[0088] Figures 2-4 The images show the SEM cross-sectional morphology of Examples 1-3 and Comparative Examples 1 and 2. The samples in Comparative Examples 1 and 2 are single-layer structures, while the samples in Examples 1-3 are multi-layer stacked structures, which is beneficial for improving corrosion resistance.
[0089] Figure 9The wavelength transmittance curves for Examples 1-3 and Comparative Examples 1 and 2 are shown. The average transmittance of the comparative sample and the examples in the visible light band is very close, both exceeding 91%. This indicates that the multilayer structure of the examples does not have a negative impact on optical performance and has good optical transmittance.
[0090] Figure 10 The graphs show the potentiodynamic polarization test curves for Examples 1-3 and Comparative Examples 1 and 2. It can be seen from the graphs that the overall current density of the samples in Examples 1-3 is lower than that in Comparative Examples 1 and 2, indicating that the multilayer structure contributes to the improvement of the film's corrosion resistance. Furthermore, as the number of deposition cycles increases, the corrosion current in Examples 1-3 further decreases, indicating that the alternating deposition of silicon oxide and aluminum oxide multilayer films prepared in this invention has excellent corrosion resistance, and that increasing the number of deposition cycles is beneficial to improving corrosion resistance.
[0091] Figure 11 To Figure 10 The corrosion current density and corrosion potential obtained by fitting the potentiodynamic polarization curves show that the comparative sample has a higher corrosion current density and corrosion potential, while the corrosion current and corrosion potential of the embodiment are significantly lower than those of the comparative sample, indicating that the silicon oxide and aluminum oxide alternating deposition multilayer thin film prepared by the present invention has excellent corrosion resistance.
[0092] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.
Claims
1. A multilayer thin film with alternating deposition of alumina and silicon oxide, characterized in that, The thin film comprises an aluminum oxide layer and a silicon oxide layer sequentially from the metal substrate to the surface, with the aluminum oxide layer to silicon oxide layer having a thickness ratio of 2:1, and the total thickness of the thin film being 1300-1500 nm.
2. The alumina-silicon oxide alternating deposition multilayer thin film as described in claim 1, characterized in that, Both the alumina layer and the silicon oxide layer are amorphous short-range ordered and long-range disordered structures, and the metal substrate is any one of pure copper, cemented carbide, stainless steel, and copper alloy materials.
3. A method for preparing a multilayer thin film of alternating alumina and silicon oxide deposition as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Grind the metal substrate with SiC sandpaper in sequence, and then polish it with polishing paste until it is mirror smooth. S2, the metal substrate polished in step S1 is ultrasonically cleaned with anhydrous ethanol and deionized water for 20-30 minutes, and then dried with dry nitrogen gas for later use. S3. Fix the metal substrate dried in step S2 onto the sample holder of the magnetron sputtering device. After the chamber is evacuated, argon gas is introduced to perform argon ion etching for 5 to 10 minutes. S4. After the argon ion etching in step S3 is completed, argon gas is introduced to perform sputter cleaning of Al and Si targets. S5. After the target washing in step S4 is completed, argon and oxygen are introduced, the Al target is opened, and an Al2O3 layer is sputtered and deposited. S6. After the Al2O3 layer is deposited in step S5, argon and oxygen are introduced, the Si target is turned on, and the SiO2 layer is sputtered and deposited. S7. Repeat steps S5 and S6, alternatingly depositing Al2O3 and SiO2 layers until the desired thin film is obtained.
4. The method for preparing a multilayer thin film by alternating deposition of alumina and silicon oxide as described in claim 3, characterized in that, In step S1, the metal substrate is polished sequentially with SiC sandpaper of different grit numbers, namely 600#, 800#, 1000#, 1500#, and 2000#, and the polishing paste is W2.
5.
5. The method for preparing a multilayer thin film by alternating deposition of alumina and silicon oxide as described in claim 3, characterized in that, In step S3, the vacuum is evacuated to 3×10⁻⁶. -3 Pa, the amount of argon gas introduced is 120-150 sccm, the working pressure is 1.0-1.5 Pa, and the substrate bias voltage is set to -800-1000 V.
6. The method for preparing a multilayer thin film of alternating alumina and silicon oxide deposition as described in claim 3, characterized in that, In step S4, the amount of argon gas introduced is 35-45 sccm, the working pressure is 0.3-0.5 Pa, the target sputtering current is set to 3-5 A, and the target washing time is 20-40 min.
7. The method for preparing a multilayer thin film by alternating deposition of alumina and silicon oxide as described in claim 3, characterized in that, In step S5, the argon gas flow rate is 35-45 sccm, the oxygen gas flow rate is 4-6 sccm, the working pressure is 0.3-0.5 Pa, the Al target sputtering current is set to 1.5-3 A, and the deposition time is 180-200 min.
8. The method for preparing a multilayer thin film by alternating deposition of alumina and silicon oxide as described in claim 3, characterized in that, In step S6, the argon gas flow rate is 35-45 sccm, the oxygen gas flow rate is 10-15 sccm, the working pressure is 0.3-0.5 Pa, the Si target sputtering current is set to 3-5 A, and the deposition time is 20-40 min.
9. The method for preparing a multilayer thin film of alternating alumina and silicon oxide deposition as described in claim 3, characterized in that, In step S7, the Al2O3 layer and the SiO2 layer are deposited alternately for 1 to 3 cycles.
10. The application of an alternating alumina and silicon oxide multilayer thin film as described in claim 1 or 2 in the field of electronic device protection.