Metal ion doped lithium niobate single crystal film, doping method and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor element preparation, in particular to a metal ion doped lithium niobate single crystal thin film, a doping method thereof and a preparation method of the metal ion doped lithium niobate single crystal thin film. The doping method comprises the following steps: injecting doped metal ions into a wafer 1 to generate injection damage to form a wafer 1 injection body, wherein the wafer 1 injection body sequentially comprises a thin film layer, a damage layer and a residual layer; wherein the wafer 1 is a wafer which is not doped with metal ions; then, the wafer base body with the transition layer arranged on the surface is bonded with the injection body of the wafer 1 to form a composite body, and the transition layer is bonded with the thin film layer; next, annealing is carried out for multiple times, so that the residual layer is stripped from the composite body, and the doped ions are uniformly distributed and diffused into the thin film layer; the doping method can improve the doping uniformity of the metal ions. Meanwhile, He < + > which does not belong to crystal components is not used in the whole doping method, doping agent ions are directly used for stripping, waste of He is avoided, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor element preparation, in particular to a metal ion doped lithium niobate single crystal thin film, a doping method thereof and a preparation method thereof. BACKGROUND

[0002] When a semiconductor element is prepared using a crystal material, the crystal material often needs to be doped to modify it and improve its performance. For example, when lithium niobate is used as a photonic device, it often needs to be doped with metal ions such as magnesium ions to improve the damage threshold. In order to obtain a lithium niobate single crystal thin film, He + needs to be ion implanted onto the surface of a wafer.

[0003] Specifically, the existing preparation method of the metal ion doped lithium niobate single crystal thin film is as follows: a dopant containing doped metal ions is added to the raw material for forming lithium niobate, and then a lithium niobate crystal containing doped metal ions is obtained through crystal growth. Then, a wafer containing doped metal ions is obtained through a process, and then a layer of thin film is peeled off through an ion slicing method, and finally a metal ion doped lithium niobate single crystal thin film is obtained. Taking magnesium ions as an example for further description, the preparation of the magnesium ion doped lithium niobate single crystal thin film is as follows: mix target proportions of lithium carbonate, niobium oxide and magnesium oxide powders uniformly, and place them in a muffle furnace for heating (for example, heating at 1150℃ for 20h). Lithium niobate crystals are obtained through a Czochralski crystal growth process, and then directional cutting, rounding, slicing, grinding and polishing, He + implantation, PECVD deposition, bonding and annealing peeling are performed.

[0004] It can be seen that the existing preparation method of the metal ion doped lithium niobate single crystal thin film has the following disadvantages: (1) a doped metal ion crystal needs to be prepared, and the doped metal ion crystal usually needs to be grown at a lower speed, which reduces the yield of single crystals. (2) The doped metal ions in the crystal cause lattice distortion, which in turn causes the crystal to crack and reduces the yield. (3) Due to convection instability, the distribution of doped metal ions in the grown crystal is not uniform. (4) He + implantation is used, which causes waste of He + . The above defects limit the application of the metal ion doped lithium niobate single crystal thin film. Therefore, there is an urgent need for a new doping method for the metal ion doped lithium niobate single crystal thin film to improve or overcome the above defects.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a metal ion doped lithium niobate single crystal thin film, a doping method thereof and a preparation method thereof. The doping method provided by the embodiments of the present application can overcome the defects of the above existing doping method or preparation method.

[0007] The present application is implemented as follows:

[0008] In a first aspect, the present application provides a method for doping a lithium niobate single crystal thin film with metal ions, comprising:

[0009] A wafer 1 is injected with doping metal ions by an ion implanter to form an injected wafer 1, which comprises a thin film layer, a damage layer and a residual layer in sequence; wherein the wafer 1 is a wafer without doping metal ions;

[0010] Then, a wafer substrate with a transition layer on the surface is bonded with the injected wafer 1 by direct bonding to form a composite, wherein the transition layer is bonded with the thin film layer;

[0011] Subsequently, multiple annealing is performed to separate the residual layer from the composite and to diffuse the doping ions into the thin film layer.

[0012] In an optional embodiment, the wafer 1 is a lithium niobate wafer without doping metal ions.

[0013] In an optional embodiment, the conditions for injecting the doping metal ions into the wafer 1 include: an injection energy of 100-300 keV, an injection dose of (1-5) x 1014 ions / cm2, and an injection angle of 0-10°. 16 ions / cm 2 .

[0014] In an optional embodiment, the doping metal ions include any one of magnesium ions, copper ions, iron ions, zinc ions and silver ions.

[0015] In an optional embodiment, the transition layer is a silicon dioxide layer.

[0016] The thickness of the silicon dioxide layer is 1-3 microns.

[0017] In an optional embodiment, the step of forming the transition layer includes: depositing a material for forming the transition layer on the surface of a wafer 2, and then annealing at 330-360 °C for 5-10 hours.

[0018] In an optional embodiment, the wafer 2 is a lithium niobate wafer without doping metal ions or a silicon wafer without doping metal ions.

[0019] In an optional embodiment, the wafer 2 is a lithium niobate wafer without doping metal ions or a silicon wafer without doping metal ions.

[0020] Then, the damaged layer is annealed at 330-360℃ for 5-10 hours to make the doped ions in the damaged layer diffuse uniformly into the thin film layer.

[0021] In a second aspect, the present application provides a method for preparing a metal ion doped lithium niobate single crystal thin film, which comprises the metal ion doping method of any one of the preceding embodiments.

[0022] In a third aspect, the present application provides a metal ion doped lithium niobate single crystal thin film, which is prepared by the metal ion doping method of any one of the preceding embodiments or the method for preparing a metal ion doped lithium niobate single crystal thin film.

[0023] The present application has the following beneficial effects: the doping method provided by the embodiments of the present application can improve the uniformity of metal ion doping by doping metal ions into a wafer without metal ions and then annealing to make the metal ions diffuse. Meanwhile, the entire doping method does not use He which does not belong to the crystal component + and directly uses dopant ions for stripping, thereby avoiding waste of He and reducing costs. Meanwhile, the wafer of the present application is a wafer without metal ions, that is, lithium niobate crystals are grown by the Czochralski method without doping, thereby improving the crystal growth speed, improving the production capacity, reducing the crystal distortion, and improving the yield of products. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0025] Figure 1 The Mg element content distribution result of the metal ion doped lithium niobate single crystal thin film provided for the embodiment 1 of the present application is shown in the following figure:

[0026] Figure 2 The Zn element content distribution result of the metal ion doped lithium niobate single crystal thin film provided for the embodiment 3 of the present application is shown in the following figure:

[0027] Figure 3 The Mg element content distribution result of the metal ion doped lithium niobate single crystal thin film provided for the comparative example 1 of the present application is shown in the following figure:

[0028] Figure 4 The Zn element content distribution result of the metal ion doped lithium niobate single crystal thin film provided for the comparative example 3 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0029] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not indicated, the conventional products that can be purchased in the market are adopted.

[0030] In a first aspect, the present application provides a doping method of a lithium niobate single crystal thin film doped with metal ions, comprising:

[0031] The metal ion doping is injected into the wafer 1, a transition layer is deposited on the wafer 2, and then the wafer 1 and the wafer 2 are bonded and annealed, so that a single crystal thin film can be peeled off from the wafer 1, and the metal ion doping is uniformly dispersed in the thin film. After chemical mechanical polishing and the like, a lithium niobate single crystal thin film doped with metal ions is obtained, which can be used for optoelectronic devices.

[0032] According to the present application, the metal ion doping is injected after the wafer is formed, and then annealing is performed, so that the uniformity of doping is greatly improved. In addition, the He + which does not belong to the crystal components is not used, and the peeling is directly performed using the dopant ions, so that the waste of He is avoided, and the cost is reduced.

[0033] Specifically, the doping process is as follows:

[0034] S1, preparing a wafer 1 and a wafer 2

[0035] The wafer 1 used in the embodiments of the present application is a lithium niobate wafer without metal ion doping. The wafer 2 is a lithium niobate wafer without metal ion doping or a silicon wafer without metal ion doping. The above-mentioned wafer 1 and wafer 2 can be formed by growing single crystals by the Czochralski method.

[0036] Specifically, the present application is described by taking a lithium niobate wafer without metal ion doping as an example. The lithium niobate crystal grown by the Czochralski method is annealed, directionally cut, polarized, rounded, sliced, and polished to obtain a lithium niobate wafer without metal ion doping. Specifically, the lithium niobate and the niobium oxide powder are mixed according to the same component ratio, heated in a muffle furnace (for example, sintered at 1150℃ for 20h), taken out and placed in a platinum crucible, and the single crystal is grown by the Czochralski method. That is, the lithium niobate crystal is obtained after the melting, crystal lowering, necking, shoulder placing, constant diameter and tailing. The crystal is cut along the specified crystal direction, and rounded, sliced, polished and obtained as a lithium niobate wafer without metal ion doping of the same component.

[0037] The lithium niobate wafer provided in the embodiment of the present invention is formed by single crystal growth using the Czochralski method. It can be seen that no metal ion doping occurs during the single crystal growth stage using the Czochralski method, thereby increasing the crystal growth rate and productivity, while reducing lattice distortion and improving yield.

[0038] S2, injecting metal ions;

[0039] Doped metal ions are injected into wafer 1 to produce injection damage, forming the implanted body of wafer 1. This implanted body sequentially comprises a thin film layer, a damaged layer, and a residual layer. Implanting doped metal ions at a certain depth disrupts chemical bonds, subsequently forming a damaged layer. The specific depth is determined by the injection energy. Wafer 1 is the undoped lithium niobate wafer prepared in S1.

[0040] Specifically, the implantation conditions include an implantation energy of 100-300keV, such as any value between 100-300keV, such as 100keV, 150keV, 200keV, 250keV, or 300keV. If the implantation energy is too high, the damaged layer will be too thick and the damage will be excessive, thereby reducing the product yield. If the implantation energy is too low, the damage will be too little, making it difficult to separate the residual material layer from the damaged layer. This will cause the damaged layer and the thin film layer to be easily damaged during the peeling process, and thus the formation of a lithium niobate single crystal thin film will be impossible.

[0041] The injection dose is (1-5)×10 16 ions / cm 2 , for example, 1×10 16 ions / cm 2 , 1.5×10 16 ions / cm 2 , 2×10 16 ions / cm 2 , 2.5×10 16 ions / cm 2 , 3×10 16 ions / cm 2 , 3.5×10 16 ions / cm 2 , 4×10 16 ions / cm 2 , 4.5×10 16 ions / cm 2 or 5×10 16 ions / cm 2 etc. (1-5)×10 16 ions / cm 2If the injection dose is too high, it will cause excessive damage, thereby reducing the product yield. If the injection dose is too low, it will make the residual layer difficult to peel off, which may easily lead to the breakage of the film layer and the damaged layer, and thus easily affect the product yield.

[0042] The implantation dose and implantation energy provided by the embodiment of the present invention can ensure the depth of the formed damaged layer, which is beneficial to the stripping of the residual layer, reduces the damage to the damaged layer, especially the thin film layer, and improves the yield rate.

[0043] The thickness of the damaged layer is very thin and can be ignored. The damaged layer can be regarded as a surface of the thin film layer. The embodiment of the present invention is only to illustrate the formation of damage in the wafer 1 after the injection of doped metal ions, and to distinguish it from the undamaged crystals in the thin film layer, and then define the damaged layer.

[0044] The doping metal ions include any one of magnesium ions, copper ions, iron ions, zinc ions and silver ions. The embodiment of the present invention is described using magnesium ions as an example.

[0045] S3, forming a wafer substrate;

[0046] A material forming the transition layer is deposited on the surface of the wafer 2. In the embodiment of the present invention, the transition layer is a silicon dioxide layer, that is, silicon dioxide is deposited on the surface of the wafer 2. The deposition method is conventional deposition conditions and steps such as chemical deposition, which will not be described in detail in the embodiment of the present invention.

[0047] The thickness of the silicon dioxide layer is 1-3 microns, for example, 1 micron, 2 microns, 3 microns, or any other value between 1-3 microns.

[0048] Annealing is performed after deposition, specifically at 330-360°C for 5-10 hours. Annealing under these conditions can improve the bond strength between the silicon dioxide and wafer 2. Annealing at too high or too low a temperature can alter the bond strength between the silicon dioxide and wafer 2, leading to reduced performance of the final product.

[0049] S4, forming a complex and annealing;

[0050] The wafer substrate is bonded to the implanted wafer 1 to form a composite, wherein the transition layer is directly bonded to the thin film layer. After annealing at 240-260°C for 5-10 hours, the thin film layer of wafer 1 is peeled off due to the different thermal expansion coefficients of the transition layer silicon dioxide and lithium niobate. This separates the residual layer from the composite, forming a multilayer structure sample comprising the thin film layer, silicon dioxide layer, and wafer 2. The surface of the thin film layer (i.e., the damaged layer) contains a high concentration of doped metal elements.

[0051] Then, the annealing temperature is increased to 330-360°C and annealed for 5-10 hours. At the above annealing temperature, the doped metal ions can diffuse evenly from the surface of the film layer (that is, the damaged layer) into the film layer, thereby obtaining a metal ion-doped lithium niobate single crystal film.

[0052] In a second aspect, the present invention provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, which includes the doping method of the metal ion-doped lithium niobate single crystal thin film described in any one of the aforementioned embodiments.

[0053] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0054] Example 1

[0055] An embodiment of the present invention provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0056] 622.56g of lithium carbonate and 2377.44g of niobium oxide powder were mixed and sintered in a muffle furnace at 1150°C for 20 hours. The polycrystalline material was removed and placed in a platinum crucible for single crystal growth using the Czochralski method. This process involved melting, crystallization, necking, shouldering, equalizing diameter, and tailing to produce lithium niobate crystals. The equalizing diameter growth rate was 3mm / h. The crystals were cut along a specified crystal orientation and then subjected to rolling, slicing, grinding, and polishing to produce lithium niobate wafers of the same composition. Wafers 1 and 2 are both lithium niobate wafers.

[0057] After cleaning the wafer 1, Mg is implanted into the wafer 1. 2+ , injection energy 300keV, injection dose 5×10 16 ions / cm 2 The wafer 1 implant is formed.

[0058] 1 micron of silicon dioxide is deposited on the surface of wafer 2 and annealed at 350° C. for 5 hours.

[0059] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the implanted body is annealed at 250°C for 5 hours and then at 350°C for 10 hours to form MgO. 2+ Doped lithium niobate single crystal thin film.

[0060] The distribution of Mg content in the metal ion-doped lithium niobate single crystal film of Example 1 was measured using an electron probe. Figure 1 , where different colors represent the relative abundance of elements.

[0061] Example 2

[0062] An embodiment of the present invention provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0063] After cleaning the wafer 1, Cu is implanted into the wafer 1. 2+ , injection energy 200keV, injection dose 2.5×10 16 ions / cm 2 The implanted body is formed on wafer 1. Wafer 1 is wafer 1 of Example 1.

[0064] 3 microns of silicon dioxide was deposited on the surface of wafer 2 and annealed at 330° C. for 10 hours. Wafer 2 was wafer 2 in Example 1.

[0065] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the implanted body is annealed at 240°C for 10 hours and then at 360°C for 5 hours to form Cu 2+ Doped lithium niobate single crystal thin film.

[0066] Example 3

[0067] An embodiment of the present invention provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0068] After cleaning the wafer 1, Zn is implanted into the wafer 1. 2+ , injection energy 100keV, injection dose 1×10 16 ions / cm 2 The implanted body is formed on wafer 1. Wafer 1 is wafer 1 of Example 1.

[0069] 2 microns of silicon dioxide are deposited on the surface of wafer 2 and annealed at 360° C. for 5 hours. Wafer 2 is wafer 2 in Example 1.

[0070] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the ZnO2 layer is annealed at 260°C for 8 hours and then at 330°C for 8 hours. 2+ Doped lithium niobate single crystal thin film.

[0071] The distribution of Zn element content in the metal ion-doped lithium niobate single crystal film of Example 3 was measured by electron probe. Figure 2 .

[0072] Comparative Example 1

[0073] This comparative example provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0074] 622.56g of lithium carbonate, 2377.44g of niobium oxide powder, and 15.49g of magnesium oxide powder were mixed and sintered in a muffle furnace at 1150°C for 20 hours. The polycrystalline material was removed and placed in a platinum crucible for single crystal growth using the Czochralski method. This process involved melting, crystallization, necking, shouldering, equalizing diameters, and tailing to produce magnesium-doped lithium niobate crystals. The equalizing diameter growth rate was 1mm / h. The crystals were cut along a specified crystal orientation and then subjected to rolling, slicing, grinding, and polishing to produce magnesium-doped lithium niobate wafers of the same composition. Wafers 1 and 2 are both examples of this magnesium-doped lithium niobate wafer.

[0075] After cleaning wafer 1, He is injected into wafer 1. + , injection energy 300keV, injection dose 5×10 16 ions / cm 2 The wafer 1 implant is formed.

[0076] 1 micron of silicon dioxide is deposited on the surface of wafer 2 and annealed at 350° C. for 5 hours.

[0077] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the implanted body is annealed at 250°C for 5 hours and then at 350°C for 10 hours to form MgO. 2+ Doped lithium niobate single crystal thin film.

[0078] The distribution of Mg content in the metal ion-doped lithium niobate single crystal film of Comparative Example 1 was tested by electron probe. Figure 3 .

[0079] Comparative Example 2

[0080] This comparative example provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0081] 622.56g of lithium carbonate, 2377.44g of niobium oxide powder, and 30.58g of copper oxide powder were mixed and sintered in a muffle furnace at 1150°C for 20 hours. The polycrystalline material was removed and placed in a platinum crucible for single crystal growth using the Czochralski method. This process involved melting, crystallization, necking, shouldering, equalizing diameters, and tailing to produce copper-doped lithium niobate crystals. The equalizing diameter growth rate was 1mm / h. The crystals were cut along a specified crystal orientation and then subjected to rolling, slicing, grinding, and polishing to produce copper-doped lithium niobate wafers of the same composition. Wafers 1 and 2 are both magnesium-doped lithium niobate wafers.

[0082] After cleaning wafer 1, He is injected into wafer 1. + , injection energy 200keV, injection dose 2.5×10 16 ions / cm 2 The wafer 1 implant is formed.

[0083] 3 microns of silicon dioxide was deposited on the surface of wafer 2 and annealed at 330° C. for 10 hours. Wafer 2 was wafer 2 in Example 1.

[0084] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the implanted body is annealed at 240°C for 5 hours and then at 360°C for 5 hours to form Cu 2+ Doped lithium niobate single crystal thin film.

[0085] Comparative Example 3

[0086] This comparative example provides a method for preparing a metal ion-doped lithium niobate single crystal thin film, comprising:

[0087] 622.56g of lithium carbonate, 2377.44g of niobium oxide powder, and 31.29g of zinc oxide powder were mixed and sintered in a muffle furnace at 1150°C for 20 hours. The polycrystalline material was removed and placed in a platinum crucible. Single crystals were grown using the Czochralski method, with a constant diameter growth rate of 1mm / h. Zinc-doped lithium niobate crystals were obtained after melting, crystal removal, necking, shoulder release, constant diameter, and tailing. The crystals were cut along the specified crystal orientation, rolled, sliced, and polished to produce zinc-doped lithium niobate wafers of the same composition. Wafers 1 and 2 are both zinc-doped lithium niobate wafers.

[0088] After cleaning wafer 1, He is injected into wafer 1. + , injection energy 150keV, injection dose 1×10 16 ions / cm 2 The wafer 1 implant is formed.

[0089] 2 microns of silicon dioxide are deposited on the surface of wafer 2 and annealed at 360° C. for 5 hours. Wafer 2 is wafer 2 in Example 1.

[0090] The implanted body of wafer 1 is bonded to the silicon dioxide layer of wafer 2. Specifically, the silicon dioxide layer is bonded to the thin film layer of the implanted body of wafer 1. Then, the ZnO2 layer is annealed at 260°C for 5 hours and then at 330°C for 8 hours. 2+ Doped lithium niobate single crystal thin film.

[0091] The distribution of Zn element content in the metal ion-doped lithium niobate single crystal film of Comparative Example 3 was tested by electron probe. Figure 4 .

[0092] By comparison Figure 1 and Figure 3 as well as Figure 2 and Figure 4 It can be seen that the doping method provided by the embodiment of the present invention can significantly improve the doping uniformity of elements.

[0093] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for doping a metal ion-doped lithium niobate single crystal thin film, characterized in that: include: Doped metal ions are injected into the wafer 1 to generate injection damage to form an implanted body of the wafer 1, wherein the implanted body of the wafer 1 sequentially includes a thin film layer, a damage layer, and a residual layer; wherein the wafer 1 is a wafer not doped with metal ions; Then, a wafer substrate with a transition layer provided on its surface is bonded to the wafer 1 implant to form a composite body, wherein the transition layer is bonded to the thin film layer; Then, multiple annealing processes are performed to separate the residual layer from the composite body, and to evenly diffuse the doping ions into the thin film layer.

2. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 1, wherein: The wafer 1 is a lithium niobate wafer not doped with metal ions.

3. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 1, wherein: The conditions for injecting the doped metal ions into the wafer 1 include: an injection energy of 100-300 keV, an injection dose of (1-5)×10 16 ions / cm 2 .

4. The method for doping a metal ion-doped lithium niobate single crystal thin film according to any one of claims 1 to 3, characterized in that: The doping metal ions include any one of magnesium ions, copper ions, iron ions, zinc ions and silver ions.

5. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 1, wherein: The transition layer is a silicon dioxide layer; The thickness of the silicon dioxide layer is 1-3 microns.

6. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 1, wherein: The step of forming the transition layer includes: depositing a material for forming the transition layer on the surface of the wafer 2, and then annealing at 330-360°C for 5-10 hours.

7. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 6, wherein: The wafer 2 is a lithium niobate wafer not doped with metal ions or a silicon wafer not doped with metal ions.

8. The method for doping a metal ion-doped lithium niobate single crystal thin film according to claim 1, wherein: include: annealing the composite at 240-260° C. for 5-10 hours to separate the residual layer from the composite; Then, annealing is performed at 330-360° C. for 5-10 hours to allow the doped ions in the damaged layer to diffuse evenly into the thin film layer.

9. A method for preparing a metal ion-doped lithium niobate single crystal thin film, characterized in that: The method comprises the doping method of the metal ion-doped lithium niobate single crystal film according to any one of claims 1 to 8.

10. A metal ion-doped lithium niobate single crystal thin film, characterized in that: The lithium niobate single crystal film is prepared by the doping method of the metal ion-doped lithium niobate single crystal film according to any one of claims 1 to 8 or the preparation method of the metal ion-doped lithium niobate single crystal film according to claim 9.

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