A blackened single crystal piezoelectric composite film based on ion implantation and a preparation method thereof

Abstract

A blackened single-crystal piezoelectric composite film based on ion implantation and a preparation method thereof disclosed in the present application utilize the ion implantation technology. First, stripping ions are implanted into a lithium niobate or lithium tantalate wafer, and then reducing ions are implanted into the thin film layer of the lithium niobate or lithium tantalate wafer. After bonding and heat treatment steps, the stripping ion implantation causes the bonded body to separate at the separation layer. The reducing ion implantation will occupy the lattice points of the originally higher-valent ions in the thin film layer, increasing the oxygen vacancy concentration in the lithium niobate or lithium tantalate crystal, improving the carrier concentration in the single-crystal thin film, thereby increasing the conductivity of the single-crystal thin film and reducing the resistivity. Subsequently, annealing repair is performed on the single-crystal thin film, which can effectively reduce the pyroelectric effect of the composite film.

Description

Technical Field

[0001] This application belongs to the technical field of semiconductor preparation, and particularly relates to a blackened single-crystal piezoelectric composite thin film based on ion implantation and a preparation method thereof. Background Art

[0002] Lithium niobate and lithium tantalate crystals have been widely used in various core electronic components such as surface acoustic wave devices, thin film bulk acoustic wave resonators, and optoelectronic sensors due to their excellent optical properties such as piezoelectricity, ferroelectricity, optoelectronic, photoelastic, pyroelectric, photorefractive, and nonlinear optical properties.

[0003] Since both lithium niobate and lithium tantalate crystals are ferroelectric crystals, they have relatively high pyroelectric coefficients and resistivity. Thus, when preparing electronic components using lithium niobate and lithium tantalate wafers, a large amount of static charge is likely to accumulate on the surfaces of the lithium niobate and lithium tantalate wafers, and the release of these static charges will damage the lithium niobate and lithium tantalate wafers, thereby affecting the performance and yield of the prepared electronic components.

[0004] To solve the above problems, in one implementation, the lithium niobate and lithium tantalate wafers are pre-blackened. Herein, the blackening treatment refers to treating the lithium niobate and lithium tantalate wafers by methods such as high-temperature chemical reduction to reduce the pyroelectric effect and resistivity of the lithium niobate and lithium tantalate wafers. After the blackening treatment, the lithium niobate and lithium tantalate wafers will change from a colorless and transparent state to a tea color; further, using the blackened lithium niobate and lithium tantalate wafers to prepare electronic components can solve the problem that the release of static charges will damage the lithium niobate or lithium tantalate wafers.

[0005] However, the applicant has found that for electronic components using piezoelectric composite thin films, although pre-blackened lithium niobate and lithium tantalate wafers are used, when the prepared piezoelectric composite thin film is applied to electronic components, there is still a phenomenon that the release of static charges damages the electronic components. Summary of the Invention

[0006] To solve the technical problem that although pre-blackened lithium niobate and lithium tantalate wafers are used in the prior art, when the prepared piezoelectric composite thin film is applied to electronic components, there is still a phenomenon that the release of static charges damages the electronic components, this application provides a blackened single-crystal piezoelectric composite thin film based on ion implantation and a preparation method thereof.

[0007] In a first aspect, this application provides a preparation method of a blackened single-crystal piezoelectric composite thin film based on ion implantation, including:

[0008] Prepare a first wafer and a substrate, wherein the first wafer is a lithium niobate wafer or a lithium tantalate wafer;

[0009] Inject a first ion into the first wafer, and sequentially divide the first wafer into a residual layer, a separation layer, and a thin film layer;

[0010] Bond the first wafer to the substrate to obtain a bonded body;

[0011] Heat-treat the bonded body to separate the residual layer from the thin film layer, and obtain a single-crystal piezoelectric composite film;

[0012] Wherein, after injecting the first ion into the first wafer and before obtaining the bonded body, inject a second ion into the thin film layer; or, after obtaining the single-crystal piezoelectric composite film, inject a second ion onto the surface of the thin film layer, wherein the second ion is a reducing ion;

[0013] Perform blackening reduction heat treatment on the single-crystal piezoelectric composite film to obtain a blackened single-crystal piezoelectric composite film.

[0014] In one implementable manner, if the second ion is a hydrogen ion, then after injecting the first ion into the first wafer and before obtaining the bonded body, inject hydrogen ions into the thin film layer.

[0015] In one implementable manner, if the second ion is a reducing metal ion, then after obtaining the single-crystal piezoelectric composite film, inject a reducing metal ion onto the surface of the thin film layer.

[0016] In one implementable manner, performing blackening reduction heat treatment on the single-crystal piezoelectric composite film includes:

[0017] Keep the single-crystal piezoelectric composite film at 300 - 600 °C for 1 - 100 hours.

[0018] In one implementable manner, the injection dose of the second ion is less than the critical injection dose, and the critical injection dose is the minimum injection dose that causes the thin film layer to delaminate.

[0019] In one implementable manner, the injection dose of the first ion is 2×10 16 ions / cm 2 -4×10 16 ions / cm 2 , the injection energy is 40 - 400 keV; the injection dose of the second ion is 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the injection energy is 15 - 390 keV.

[0020] In one implementable manner, the injection dose of the first ion is 2×1016 ions / cm 2 -4×10 16 ions / cm 2 , the implantation energy is 40 - 400 keV; the implantation dose of the second ion is 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the implantation energy is 20 - 130 keV.

[0021] In one realizable manner, if the reducing metal ion is a magnesium ion, the depth of implanting magnesium ions into the surface of the thin film layer is 26 nm, and the implantation energy is 20 keV; if the reducing metal ion is a zinc ion, the depth of implanting zinc ions into the surface of the thin film layer is 63 nm, and the implantation energy is 130 keV.

[0022] In one realizable manner, the preparation method further includes: polishing and cleaning the surface of the thin film layer in the blackened single crystal piezoelectric composite film.

[0023] In one realizable manner, the substrate is a single-layer substrate or a composite substrate.

[0024] In a second aspect, the present application provides a blackened single crystal piezoelectric composite film, which is prepared by the preparation method of the blackened single crystal piezoelectric composite film based on ion implantation according to any one of the first aspect.

[0025] In a third aspect, the present application further provides an electronic component, and the electronic component includes the blackened single crystal piezoelectric composite film described in the second aspect.

[0026] In summary, the present application provides a blackened single crystal piezoelectric composite film based on ion implantation and its preparation method. By using the ion implantation technology, first, the stripping ions are implanted into the lithium niobate or lithium tantalate wafer, and then the reducing ions are implanted into the thin film layer of the lithium niobate or lithium tantalate wafer. After the bonding and heat treatment steps, the stripping ion implantation causes the bonded body to separate at the separation layer. The reducing ion implantation will occupy the lattice points of the originally higher-valent ions in the thin film layer, increasing the oxygen vacancy concentration in the lithium niobate or lithium tantalate crystal, improving the carrier concentration in the single crystal film, thereby increasing the conductivity of the single crystal film and reducing the resistivity. Subsequently, annealing repair is performed on the single crystal film, which can effectively reduce the pyroelectric effect of the composite film. In this way, without affecting the piezoelectric properties of the material, blackening can be achieved based on ion implantation to obtain a high-quality blackened single crystal piezoelectric composite film. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 The flowchart of a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation provided in Embodiment 1 of the present application;

[0029] Figure 2 The flowchart of a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation provided in Embodiment 2 of the present application.

[0030] Explanation of reference numerals

[0031] 100 - First wafer, 110 - Residual layer, 120 - Separation layer, 130 - Thin film layer, 130A - Blackened thin film layer, 200 - Substrate, 300 - Bonding body. Detailed implementation manners

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0033] As introduced in the background art section, to solve the technical problem that a large amount of static charges are easily accumulated on the surfaces of lithium niobate and lithium tantalate wafers, and the release of these static charges will damage the lithium niobate and lithium tantalate wafers, usually the lithium niobate and lithium tantalate wafers are pre-blackened, and then the blackened lithium niobate and lithium tantalate wafers are used to prepare piezoelectric composite films.

[0034] However, the applicant found that when the above piezoelectric composite film is applied to electronic components, there is still a phenomenon that the release of static charges damages the electronic components. Based on this, the applicant further studied and analyzed and found that: during the preparation of the piezoelectric composite film, after the lithium niobate or lithium tantalate thin film layer is separated from the residual layer, the bonding body of the thin film layer and the substrate wafer is subjected to high-temperature annealing to further enhance the bonding force and eliminate the lattice defects formed in the thin film layer during the ion implantation process. However, the applicant found that during the high-temperature annealing process, the thin film layer that should originally be brownish has a phenomenon of partial or complete whitening, that is, the originally blackened thin film layer in the finally prepared composite film material resumes the characteristics of having a relatively high pyroelectric coefficient and resistivity, thereby affecting the performance of the electronic components to which it is applied.

[0035] Based on the above analysis, an embodiment of the present application provides a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation, which can solve the technical problem that the piezoelectric composite film prepared from a blackened lithium niobate or lithium tantalate wafer still has the phenomenon of static charge release damaging electronic components.

[0036] The following details a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation provided by an embodiment of the present application.

[0037] Embodiment 1

[0038] As Figure 1 shown, a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation provided by an embodiment of the present application includes the following steps:

[0039] Step 110: Prepare a first wafer 100 and a substrate 200, where the first wafer 100 is a lithium niobate wafer or a lithium tantalate wafer.

[0040] In an embodiment of the present application, the first wafer 100 refers to a basic material with a certain thickness for preparing a thin film layer. Among them, the first wafer can be an unblackened wafer or a blackened wafer, and the present application does not limit this. If the first wafer is a blackened wafer, the first wafer can be obtained by direct purchase; or, the first wafer can be a lithium niobate wafer or a lithium tantalate wafer that is directly purchased and unblackened, and is blackened. Among them, the blackening method for the lithium niobate wafer or the lithium tantalate wafer can adopt any existing feasible blackening method, and the present application does not limit this.

[0041] In an embodiment of the present application, the substrate 200 can be a single-layer substrate or a composite substrate, that is, the substrate 200 includes at least one substrate layer. Among them, the materials of each substrate layer can be the same or different, and the present application does not limit this. For example: the substrate layer material can be lithium niobate, lithium tantalate, quartz, silicon, sapphire, SOI, diamond, silicon carbide, silicon nitride, gallium arsenide, indium phosphide, etc., and the present application does not limit this.

[0042] Step 120: Inject a first ion into the first wafer 100, and divide the first wafer 100 into a residual layer 110, a separation layer 120, and a thin film layer 130 in sequence.

[0043] The embodiments of the present application do not particularly limit the manner of ion implantation, and any ion implantation manner in the prior art can be used. The first ion to be implanted can be an ion that can generate gas through heat treatment. For example, the first ion can be a hydrogen ion, a helium ion, a nitrogen ion, an oxygen ion, or an argon ion. When implanting the first ion, the implantation dose can be 2×10 16 ions / cm 2 ~4×10 16 ions / cm 2 , and the implantation energy can be 40 keV to 400 keV.

[0044] In the embodiments of the present application, the thickness of the thin film layer 130 can be adjusted by adjusting the implantation depth of the first ion. Specifically, the greater the implantation depth of the first ion, the greater the thickness of the prepared thin film layer 130; on the contrary, the smaller the implantation depth of the first ion, the smaller the thickness of the prepared thin film layer 130.

[0045] Step 130: Bond the first wafer 100 to the substrate 200 to obtain a bonded body 300.

[0046] After bonding, the thin film layer 130 of the first wafer 100 contacts the substrate 200 and is stacked on the substrate 200. In this way, the bonded body is sequentially stacked with a residual layer 110, a separation layer 120, a thin film layer 130, and a substrate 200 from top to bottom.

[0047] The present application does not particularly limit the bonding method, and any bonding method in the prior art can be used. For example, bonding is performed by a surface activation method to obtain a bonded body. The present application also does not limit the surface activation method. For example, methods such as plasma activation or chemical solution activation can be used.

[0048] It should be noted that the present application may further include a step of preparing an isolation layer on the substrate 200 before step 130. For example, when the substrate 200 is a single-layer silicon substrate, silicon oxide can be prepared on the single-layer silicon substrate by a thermal oxidation method, and the generated silicon oxide layer serves as the isolation layer. In this way, in step 130, the first wafer 100 is bonded to the substrate 200 with the isolation layer to obtain a bonded body.

[0049] It should also be noted that the isolation layer prepared on the substrate 200 can be single-layer or multi-layer, and the present application does not limit this. For example, an alternating stack of silicon oxide layers and silicon nitride layers is prepared on the substrate 200.

[0050] Step 140: Heat-treat the bonded body 300 to separate the residual layer 110 from the thin film layer 130 to obtain a single-crystal piezoelectric composite thin film.

[0051] The bonded body 300 is heat-treated. The heat treatment process can be carried out at 180 - 280 °C for 1 - 100 hours. During the heat treatment, bubbles are formed in the separation layer 120. For example, H ions form hydrogen gas, He ions form helium gas, etc. As the heat treatment progresses, the bubbles in the separation layer 120 merge into one piece, and finally the separation layer 120 cracks, separating the remaining layer 110 from the thin film layer 130, so that the remaining layer 110 is peeled off from the bonded body 300, and a single crystal piezoelectric composite thin film is obtained. Among them, the single crystal piezoelectric composite thin film is laminated with a thin film layer 130 and a substrate 200 from top to bottom in sequence.

[0052] When the first wafer is a blackened lithium niobate wafer or lithium tantalate wafer, after the above step 140, the applicant finds that there is a phenomenon of partial or complete whitening in the thin film layer 130 that should be brown in the single crystal piezoelectric composite thin film. Thus, it can be known that after the heat treatment of the bonded body, the originally blackened thin film layer 130 is partially or completely oxidized. In order to change this phenomenon, the following step 150 and step 160 are carried out.

[0053] It should be noted that when the first wafer is a non-blackened lithium niobate wafer or lithium tantalate wafer, the following step 150 and step 160 are also carried out to realize the blackening of the thin film layer 130, so that the thin film layer 130 in the finally prepared blackened single crystal piezoelectric composite thin film is in a completely blackened state.

[0054] Step 150: Inject second ions onto the surface of the thin film layer 130 of the single crystal piezoelectric composite thin film, where the second ions are reducing ions.

[0055] Among them, the second ions can be hydrogen ions or reducing metal ions. For example, the reducing metal ions can be Zn 2 + 、Fe 2+ 、Cu 2+ 、Mg 2+ etc., and the present application does not limit this.

[0056] It should be noted that in the embodiments of the present application, injecting the first ions is to obtain the thin film layer 130 with a target thickness from the first wafer 100, and injecting the second ions is to make the thin film layer 130 still have the effect of being blackened. Therefore, when injecting the second ions, the injection dose and energy should not only ensure that the thin film layer 130 is not delaminated, but also enable the thin film layer 130 to still have the effect of being blackened. That is, the injection dose of the second ions is less than the critical injection dose, and the critical injection dose is the minimum injection dose that causes the thin film layer 130 to delaminate.

[0057] Furthermore, if the second ions are hydrogen ions, the injection dose of the second ions can be 5×1010 ions / cm 2 -1.5×10 16 ions / cm 2 , the implantation energy is 15 - 390 keV; if the second ion is a reducing metal ion, the implantation dose of the second ion can be 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the implantation energy is 20 - 130 keV. For example, if the second ion is a magnesium ion, the depth of implanting magnesium ions into the surface of the thin film layer is 26 nm and the implantation energy is 20 keV; for another example, if the second ion is a zinc ion, the depth of implanting zinc ions into the surface of the thin film layer is 63 nm and the implantation energy is 130 keV.

[0058] Step 160, perform blackening reduction heat treatment on the single crystal piezoelectric composite thin film implanted with the second ion to obtain a blackened single crystal piezoelectric composite thin film.

[0059] The blackening reduction heat treatment process for the single crystal piezoelectric composite thin film implanted with the second ion can be to keep it at 300 - 600 °C for 1 - 100 hours, and more preferably, the blackening reduction of the thin film layer can be completed by keeping it at 500 - 600 °C for 2 - 4 hours. The blackened single crystal piezoelectric composite thin film includes a blackened thin film layer 130A and a substrate 200.

[0060] In summary, in this application, after heat-treating the bonded body, and then performing blackening reduction heat treatment on the thin film layer, it is ensured that the thin film layer in the obtained blackened single crystal piezoelectric composite thin film is in a completely blackened state. In this way, the implantation of reducing ions will occupy the lattice points of the originally higher-valent ions in the thin film layer 130, increase the oxygen vacancy concentration in the lithium niobate or lithium tantalate crystal, improve the carrier concentration in the thin film layer 130, thereby increasing the conductivity of the thin film layer 130 and reducing the resistivity. Subsequently, performing blackening reduction heat treatment repair on the thin film layer 130 can effectively reduce the pyroelectric effect of the single crystal piezoelectric composite thin film.

[0061] Example Two

[0062] Another method for preparing a blackened single crystal piezoelectric composite thin film based on ion implantation provided in the second embodiment of this application is basically the same as the first embodiment, except that in the second embodiment of this application, before obtaining the bonded body after implanting the first ion into the first wafer, the second ion is implanted into the thin film layer.

[0063] As Figure 2 shown, another method for preparing a blackened single crystal piezoelectric composite thin film based on ion implantation provided in the embodiment of this application includes the following steps:

[0064] Step 210: Prepare a first wafer 100 and a substrate 200, where the first wafer 100 is a lithium niobate wafer or a lithium tantalate wafer.

[0065] Step 220: Inject a first ion into the first wafer 100, and divide the first wafer into a residual layer 110, a separation layer 120, and a thin film layer 130 in sequence.

[0066] For the above steps 210 and 220, reference can be made to the descriptions of steps 110 and 120 in the first embodiment above, and details will not be repeated here.

[0067] Step 230: Inject a second ion into the thin film layer 130.

[0068] For step 230, reference can be made to the description of step 150 above. However, it should be noted that in the solution of injecting the second ion before obtaining the bonded body, the dose and energy of the injected second ion should meet the following requirements: First, ensure that the thin film layer peels off at the position where the first ion is injected; Second, after the residual layer peels off from the thin film layer, the injected second ion exists on the surface of the thin film layer. Therefore, the dose and energy of the second ion injected in step 230 should be less than those of the first ion injected.

[0069] For example, the first ion is a hydrogen ion, the injection dose of the first ion is 2×10 16 ions / cm 2 -4×10 16 ions / cm 2 , the injection energy is 40 - 400 keV; the second ion is a hydrogen ion, the injection dose of the second ion is 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the injection energy is 15 - 390 keV.

[0070] It should also be noted that in the preparation method provided in the second embodiment, the second ion is preferably a hydrogen ion, and in the preparation method of the first embodiment, the second ion is preferably a reducing metal ion. In this way, by directly injecting a reducing metal ion into the thin film layer on the prepared single-crystal piezoelectric composite film, the injection situation of the reducing metal ion can be better controlled to avoid introducing unnecessary impurities into the prepared blackened single-crystal piezoelectric composite film.

[0071] Step 240: Bond the first wafer and the substrate to obtain a bonded body.

[0072] For step 240, reference can be made to the description of step 130 above, and details will not be repeated here.

[0073] Step 250: Heat-treat the bonded body to separate the residual layer 130 from the thin film layer 110, obtaining a single-crystal piezoelectric composite thin film.

[0074] Step 250 can refer to the above-mentioned step 140. It should be noted that in step 250, the heat treatment process can be carried out at a temperature of 180 - 280 °C for 1 - 100 hours. During the heat treatment, the first ions injected form bubbles. As the heat treatment progresses, the bubbles of the first ions in the separation layer 120 merge into one piece, and finally the separation layer 120 cracks, separating the residual layer 110 from the thin film layer 130, so that the residual layer 110 is peeled off from the bonded body 300, obtaining a single-crystal piezoelectric composite thin film. It should also be noted that the implantation dose of the second ions is less than that of the first ions, and the implantation position of the second ions is not sufficient to layer the first wafer.

[0075] Step 260: Perform blackening reduction heat treatment on the single-crystal piezoelectric composite thin film to obtain a blackened single-crystal piezoelectric composite thin film.

[0076] In the second embodiment of the present application, by pre-injecting the second ions into the thin film layer and then performing blackening reduction heat treatment on the thin film layer injected with the second ions, on the one hand, the second ions can be used to react with the oxygen in the air during the heat treatment process to prevent the originally blackened thin film layer from being whitened. On the other hand, the implantation of the second ions will occupy the lattice points of the originally higher-valence ions in the thin film layer 130, increasing the oxygen vacancy concentration in the lithium niobate or lithium tantalate crystal, improving the carrier concentration in the thin film layer 130, thereby increasing the conductivity of the thin film layer 130 and reducing the resistivity. Subsequently, the blackening reduction heat treatment repair is performed on the thin film layer 130, which can effectively reduce the pyroelectric effect of the single-crystal piezoelectric composite thin film.

[0077] After the above-mentioned first and second embodiments prepare the blackened single-crystal piezoelectric composite thin film, it may further include steps of surface polishing and cleaning treatment of the thin film layer in the blackened single-crystal piezoelectric composite thin film, so that the surface roughness of the blackened single-crystal piezoelectric composite thin film meets the requirements.

[0078] It should be noted that the thickness of the surface polishing of the thin film layer in the blackened single-crystal piezoelectric composite thin film is based on being able to completely remove the introduced second ions. Therefore, before injecting the first ions and the second ions, it is necessary to calculate the implantation depth of the first ions and the implantation depth of the second ions according to the thickness of the target thin film layer. The present application does not limit the specific implantation depth of the first ions and the specific implantation depth of the second ions, as long as the thickness after the surface polishing of the thin film layer in the blackened single-crystal piezoelectric composite thin film is greater than or equal to the thickness of the target thin film layer.

[0079] The present application also provides a blackened single-crystal piezoelectric composite film, which is obtained by using the preparation method provided in the first or second embodiment above.

[0080] In an implementable manner, the present application provides a blackened single-crystal piezoelectric composite film, including a blackened thin film layer and a substrate stacked in sequence, wherein the substrate can be a single-layer substrate or a composite substrate.

[0081] In another implementable manner, the present application provides a blackened single-crystal piezoelectric composite film, which may further include one or more isolation layers between the blackened thin film layer and the substrate.

[0082] The present application also provides an electronic component, which uses the blackened single-crystal piezoelectric composite film provided in the embodiment of the present application. The thin film layer in the blackened single-crystal piezoelectric composite film provided in the embodiment of the present application is repaired by blackening reduction heat treatment, which can effectively reduce the pyroelectric effect of the single-crystal piezoelectric composite film. Therefore, the use performance of the electronic component will not be affected during use.

[0083] The following is an illustration of the preparation method provided in the present application through specific examples.

[0084] Example 1

[0085] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided in Example 1 includes the following steps:

[0086] ① Prepare a 200-μm silicon wafer and a 200-μm lithium niobate wafer. Fix the silicon wafer or lithium niobate on the porous ceramic chuck of the polishing equipment respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a blackened lithium niobate wafer.

[0087] ② Use the peel-off ion implantation method to implant He into the lithium niobate wafer processed in step ① + , so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the implantation surface. The implanted He + is distributed in the separation layer to obtain an implanted wafer of single-crystal lithium niobate.

[0088] When using the peel-off ion implantation method to implant He + , the injection dose parameters are: the injection dose is 2×10 16 ions / cm 2 , the injection energy is 40 keV, and the injection depth is 220 nm.

[0089] ③ Use the reductive ion implantation method to implant H into the thin film layer processed in step ② + , and the implanted H+ Ions are distributed on the surface of the thin film layer;

[0090] When using the reductive ion implantation method to implant H + The implantation dose parameters are as follows: the implantation dose is 5×10 10 ions / cm 2 , the implantation energy is 20 keV, and the implantation depth is 172 nm.

[0091] ④ Fabricate a silicon dioxide layer on the cleaned silicon wafer by LPCVD method, and then perform chemical mechanical polishing to a thickness of 100 nm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface.

[0092] ⑤ Bring the single crystal lithium niobate wafer injection sheet into contact with the silicon dioxide layer and bond them by direct bonding to obtain a bonded body.

[0093] ⑥ Under a nitrogen atmosphere, place the bonded body in an annealing furnace, keep it at 180 °C for 4 hours, the bonded body separates at the separation layer, continue to keep it at 500 °C for 4 hours, and the implanted H + undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single crystal piezoelectric composite thin film.

[0094] ⑦ Fix the blackened single crystal piezoelectric composite thin film on the porous ceramic chuck of the polishing equipment, and perform chemical mechanical polishing on the thin film layer until the reductive ions H + on the surface of the thin film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0095] The obtained blackened single crystal piezoelectric composite thin film sequentially includes a blackened single crystal thin film layer, a silicon dioxide layer, and a single crystal silicon layer, where the material of the single crystal thin film layer is single crystal lithium niobate.

[0096] Example Two

[0097] Example Two is basically the same as Example One, the difference is that in step ② of Example Two, the nitrogen ions are implanted by the stripping ion implantation method, and in step ⑥, the bonded body is placed in an annealing furnace, kept at 180 °C for 3 hours, the bonded body separates at the separation layer, continue to keep it at 600 °C for 2 hours, and the implanted nitrogen ions undergo a blackening reduction reaction in the thin film layer to obtain a blackened single crystal piezoelectric composite thin film.

[0098] Example Three

[0099] A preparation method of a blackened single crystal piezoelectric composite thin film based on ion implantation provided by Example Three includes the following steps:

[0100] ① Prepare a 200-μm-thick silicon nitride wafer and a 250-μm-thick lithium niobate wafer. Fix the silicon nitride wafer or the lithium niobate wafer on the porous ceramic chuck of the polishing equipment respectively, and perform chemical mechanical polishing to obtain a smooth surface. Then, perform semiconductor RCA cleaning on both wafers to obtain a clean surface. Among them, the lithium niobate wafer is a lithium niobate wafer after blackening treatment.

[0101] ② Use the stripping ion implantation method to implant argon ions into the lithium niobate wafer processed in step ①, so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the implantation surface. The implanted argon ions are distributed in the separation layer to obtain a single-crystal lithium niobate wafer implantation sheet.

[0102] When using the stripping ion implantation method to implant argon ions, the implantation dose parameters are: the implantation dose is 3×10 16 ions / cm 2 , the implantation energy is 400 keV, and the implantation depth is 285 nm.

[0103] ③ Use the reductive ion implantation method to implant H + into the thin film layer processed in step ②, and the implanted H + ions are distributed on the surface of the thin film layer.

[0104] When using the reductive ion implantation method to implant H + , the implantation dose parameters are: the implantation dose is 5×10 12 ions / cm 2 , the implantation energy is 30 keV, and the implantation depth is 232 nm.

[0105] ④ Use PECVD method to deposit polysilicon on the cleaned silicon nitride wafer with a thickness of 1 μm, which is the first isolation layer.

[0106] ⑤ Use thermal oxidation method to fabricate a silicon dioxide layer on the first isolation layer, which is the second isolation layer. Then, perform chemical mechanical polishing to obtain a smooth surface. The thickness of the second isolation layer is 1 μm, and RCA cleaning is performed to obtain a clean surface.

[0107] ⑥ Contact the single-crystal lithium niobate wafer implantation sheet with the silicon dioxide layer and bond them using the direct bonding method to obtain a bonded body.

[0108] ⑦ Put the bonded body into an annealing furnace and keep it at 200 °C for 3 hours. The bonded body is separated at the separation layer. Then, continue to keep it at 300 °C for 100 hours. The implanted H + undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystal piezoelectric composite film.

[0109] ⑧Fix the blackened single-crystal piezoelectric composite film on the porous ceramic chuck of the polishing equipment, and perform chemical mechanical polishing on the film layer until the reducing ions on the surface of the film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0110] The obtained blackened single-crystal piezoelectric composite film sequentially includes a blackened single-crystal film layer, a silicon dioxide layer (second isolation layer), a polysilicon layer (first isolation layer), and a silicon nitride layer, wherein the material of the single-crystal film layer is single-crystal lithium niobate.

[0111] Example 4

[0112] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example 4 includes the following steps:

[0113] ① Prepare a 300-μm silicon wafer and a 400-μm lithium tantalate wafer, fix the silicon wafer or the lithium tantalate wafer on the porous ceramic chuck of the polishing equipment respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium tantalate wafer is a blackened lithium tantalate wafer.

[0114] ② Inject He into the lithium tantalate wafer processed in step ① by the stripping ion implantation method + , so that the lithium tantalate wafer is sequentially divided into a residual layer, a separation layer, and a film layer starting from the injection surface, and the injected He + ions are distributed in the separation layer to obtain a single-crystal lithium tantalate wafer injection sheet;

[0115] When injecting He by the stripping ion implantation method + , the injection dose parameters are: the injection dose is 4×10 16 ions / cm 2 ; the injection energy is 225 keV, and the injection depth is 706 nm;

[0116] ③ Inject H into the film layer processed in step ② by the reducing ion implantation method + , and the injected H + ions are distributed on the surface of the film layer.

[0117] When injecting H by the reducing ion implantation method + , the injection dose parameters are: the injection dose is 1.5×10 16 ions / cm 2 , the injection energy is 114 keV, and the injection depth is 663 nm.

[0118] ④ Deposit amorphous silicon on the cleaned silicon wafer by PVD method with a thickness of 500 nm, which is the first isolation layer.

[0119] ⑤Fabricate a silicon dioxide layer on the first isolation layer by PECVD method with a thickness of 5 μm, which is the second isolation layer. Then perform chemical mechanical polishing to obtain a smooth surface and RCA cleaning to obtain a clean surface.

[0120] ⑥Contact the single crystal lithium tantalate wafer injection sheet with the silicon dioxide layer and bond them using the direct bonding method to obtain a bonded body.

[0121] ⑦Put the bonded body into an annealing furnace, keep it at 220 °C for 3 hours. The bonded body separates at the separation layer, and then continue to keep it at 600 °C for 1 hour. A blackening reduction reaction occurs in the thin film layer to obtain a blackened single crystal piezoelectric composite thin film.

[0122] ⑧Fix the blackened single crystal piezoelectric composite thin film on the porous ceramic chuck of the polishing equipment, perform chemical mechanical polishing on the thin film layer until the reducing ions on the surface of the thin film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0123] The obtained blackened single crystal piezoelectric composite thin film successively includes a blackened single crystal thin film layer, a silicon dioxide layer (the second isolation layer), a polysilicon layer (the first isolation layer) and a single crystal silicon layer, wherein the material of the single crystal thin film layer is single crystal lithium tantalate.

[0124] Example 5

[0125] A preparation method of a blackened single crystal piezoelectric composite thin film based on ion implantation provided by Example 5 includes the following steps:

[0126] ①Prepare a 200 μm silicon carbide wafer and a 250 μm lithium niobate wafer. Fix the silicon carbide wafer or the lithium niobate wafer on the porous ceramic chuck of the polishing equipment respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a blackened lithium niobate wafer.

[0127] ②Inject He into the lithium niobate wafer processed in step ① by the stripping ion implantation method + , so that the lithium niobate wafer is successively divided into a residual layer, a separation layer and a thin film layer starting from the injection surface. The injected He + is distributed in the separation layer to obtain a single crystal lithium niobate wafer injection sheet.

[0128] When injecting He by the stripping ion implantation method + , the injection dose parameters are: the injection dose is 3×10 16 ions / cm 2 , the injection energy is 35 keV, and the injection depth is 165 nm.

[0129] ③Inject H into the thin film layer processed in step ② by the reducing ion implantation method +, the implanted H + ions are distributed on the surface of the thin film layer.

[0130] When using the reductive ion implantation method to implant H + , the implantation dose parameters are: the implantation dose is 5×10 13 ions / cm 2 , the implantation energy is 15 keV, 130 nm.

[0131] ④ Argon ions are implanted into the cleaned silicon carbide wafer by ion implantation to produce a damaged layer of single crystal silicon, which is the first isolation layer, and the thickness of the first isolation layer is 5 μm.

[0132] ⑤ A silicon dioxide layer is fabricated on the first isolation layer by PECVD method, which is the second isolation layer, and then chemical mechanical polishing is carried out to obtain a smooth surface. The thickness of the second isolation layer is 500 nm, and RCA cleaning is performed to obtain a clean surface.

[0133] ⑥ The single crystal lithium niobate wafer injection sheet is brought into contact with the silicon dioxide layer and bonded by direct bonding to obtain a bonded body.

[0134] ⑦ The bonded body is placed in an annealing furnace and kept at 240 °C for 2 hours. The bonded body is separated at the separation layer, and then kept at 550 °C for 3 hours. The implanted H + undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single crystal piezoelectric composite thin film.

[0135] ⑧ The blackened single crystal piezoelectric composite thin film is fixed on the porous ceramic chuck of the polishing equipment, and the thin film layer is subjected to chemical mechanical polishing treatment until the reducing ions on the surface of the thin film layer are removed, and then RCA cleaning is carried out to obtain a clean surface.

[0136] The obtained blackened single crystal piezoelectric composite thin film successively includes a blackened single crystal thin film layer, a silicon dioxide layer (the second isolation layer), a polysilicon layer (the first isolation layer), and a silicon nitride layer, wherein the material of the single crystal thin film layer is single crystal lithium niobate.

[0137] Example Six

[0138] A preparation method of a blackened single crystal piezoelectric composite thin film based on ion implantation provided by Example Six includes the following steps:

[0139] ① Prepare a 410 μm silicon carbide wafer and a 300 μm lithium niobate wafer. The silicon carbide wafer or the lithium niobate wafer is respectively fixed on the porous ceramic chuck of the polishing equipment, and chemical mechanical polishing treatment is carried out to obtain a smooth surface, and then semiconductor RCA cleaning is performed on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a blackened lithium niobate wafer.

[0140] ② Inject He into the lithium niobate wafer processed in step ① using the lift-off ion implantation method + , so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the implantation surface. The injected He + is distributed in the separation layer to obtain a single-crystal lithium niobate wafer implantation sheet.

[0141] When injecting He using the lift-off ion implantation method + , the injection dose parameters are: the injection dose is 3×10 16 ions / cm 2 , the injection energy is 400 keV, and the injection depth is 1.14 μm.

[0142] ③ Inject H into the thin film layer processed in step ② using the reductive ion implantation method + , and the injected H + ions are distributed on the surface of the thin film layer.

[0143] When injecting H using the reductive ion implantation method + , the injection dose parameters are: the injection dose is 5×10 13 ions / cm 2 , the injection energy is 185 keV, 1.09 μm.

[0144] ④ Inject argon ions into the cleaned silicon carbide wafer using the ion implantation method to fabricate a damaged layer of single crystal silicon, which is the first isolation layer, and the thickness of the first isolation layer is 5 μm.

[0145] ⑤ Fabricate a silicon dioxide layer on the first isolation layer using the PECVD method, which is the second isolation layer, and then perform chemical mechanical polishing to obtain a smooth surface. The thickness of the second isolation layer is 500 nm, and RCA cleaning is performed to obtain a clean surface.

[0146] ⑥ Bring the single-crystal lithium niobate wafer implantation sheet into contact with the silicon dioxide layer and bond them using the direct bonding method to obtain a bonded body.

[0147] ⑦ Place the bonded body in an annealing furnace, keep it at 240 °C for 2 hours, the bonded body disconnects and separates at the separation layer, and continue to keep it at 600 °C for 1 hour. The injected H + undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystal piezoelectric composite film.

[0148] ⑧ Fix the blackened single-crystal piezoelectric composite film on the porous ceramic chuck of the polishing equipment, perform chemical mechanical polishing on the thin film layer until the reducing ions on the surface of the thin film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0149] The obtained blackened single-crystal piezoelectric composite film successively includes a blackened single-crystal film layer, a silicon dioxide layer (second isolation layer), a polysilicon layer (first isolation layer), and a silicon nitride layer, wherein the material of the single-crystal film layer is single-crystal lithium niobate.

[0150] Example VII

[0151] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example VII includes the following steps:

[0152] ① Prepare a 300-μm silicon wafer and a 400-μm lithium tantalate wafer. Fix the silicon wafer or the lithium tantalate wafer on the porous ceramic chuck of the polishing equipment respectively, and perform chemical mechanical polishing to obtain a smooth surface. Then, perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium tantalate wafer is a blackened lithium tantalate wafer.

[0153] ② Use the stripping ion implantation method to implant H + into the lithium tantalate wafer processed in step ①, so that the lithium tantalate wafer is successively divided into a residual layer, a separation layer, and a film layer starting from the implantation surface. The implanted H + ions are distributed in the separation layer to obtain an implanted wafer of single-crystal lithium tantalate;

[0154] When using the stripping ion implantation method to implant H + , the implantation dose parameters are: the implantation dose is 4×10 16 ions / cm 2 ; the implantation energy is 400 keV, and the implantation depth is 2.62 μm;

[0155] ③ Use the reductive ion implantation method to implant H + into the film layer processed in step ②, and the implanted H + ions are distributed on the surface of the film layer.

[0156] When using the reductive ion implantation method to implant H + , the implantation dose parameters are: the implantation dose is 5×10 15 ions / cm 2 , the implantation energy is 390 keV, and the implantation depth is 2.54 μm.

[0157] ④ Use the PVD method to deposit amorphous silicon on the cleaned silicon wafer with a thickness of 500 nm, which is the first isolation layer.

[0158] ⑤ Use the PECVD method to deposit a silicon dioxide layer with a thickness of 5 μm on the first isolation layer, which is the second isolation layer. Then, perform chemical mechanical polishing to obtain a smooth surface and RCA cleaning to obtain a clean surface.

[0159] ⑥Inject the single-crystal lithium tantalate wafer injection sheet into contact with the silicon dioxide layer, and bond it using the direct bonding method to obtain a bonded body.

[0160] ⑦Place the bonded body in an annealing furnace, keep it at 220 °C for 3 hours, the bonded body separates at the separation layer, continue to keep it at 600 °C for 1 hour, and a blackening reduction reaction occurs in the thin film layer to obtain a blackened single-crystal piezoelectric composite film.

[0161] ⑧Fix the blackened single-crystal piezoelectric composite film on the porous ceramic chuck of the polishing equipment, perform chemical mechanical polishing on the thin film layer until the reducing ions on the surface of the thin film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0162] The obtained blackened single-crystal piezoelectric composite film successively includes a blackened single-crystal thin film layer, a silicon dioxide layer (second isolation layer), a polysilicon layer (first isolation layer), and a single-crystal silicon layer, wherein the material of the single-crystal thin film layer is single-crystal lithium tantalate.

[0163] Example VIII

[0164] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example VIII includes the following steps:

[0165] ①Prepare a 200-μm silicon wafer and a 200-μm lithium niobate wafer, fix the silicon wafer or lithium niobate on the porous ceramic chuck of the polishing equipment respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a blackened lithium niobate wafer.

[0166] ②Inject He into the lithium niobate wafer processed in step ① using the stripping ion implantation method + , so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the injection surface, and the injected He + is distributed in the separation layer to obtain a single-crystal lithium niobate wafer injection sheet.

[0167] When injecting He using the stripping ion implantation method + , the injection dose parameters are: the injection dose is 4×10 16 ions / cm 2 , the injection energy is 250 keV, and the injection depth is 830 nm.

[0168] ③Fabricate a silicon dioxide layer on the cleaned silicon wafer using the LPCVD method, and then perform chemical mechanical polishing to a thickness of 100 nm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface.

[0169] ④Inject the single-crystal lithium niobate wafer injection sheet into contact with the silicon dioxide layer, and bond it using the direct bonding method to obtain a bonded body.

[0170] ⑤ Under a nitrogen atmosphere, place the bonded body into an annealing furnace, keep it at 180 °C for 4 hours. The bonded body disconnects and separates at the separation layer, and then anneal it at 300 °C for 2 hours to obtain a single-crystal piezoelectric composite film.

[0171] ⑥ For the film layer on the single-crystal piezoelectric composite film after the treatment in step ⑤, inject Fe by a reducing ion implantation method 2+ , and the injected Fe 2+ ions are distributed on the surface of the film layer; then, place it into a blackening furnace, under a nitrogen atmosphere, keep it at 500 °C for 4 hours, and the injected Fe 2+ undergoes a blackening reduction reaction in the film layer to obtain a blackened single-crystal piezoelectric composite film.

[0172] When injecting Fe by a reducing ion implantation method 2+ , the injection dose parameters are: the injection dose is 5×10 13 ions / cm 2 , the injection energy is 110 keV, and the injection depth is 61 nm.

[0173] ⑦ Fix the blackened single-crystal piezoelectric composite film on the porous ceramic chuck of a polishing device, and perform chemical mechanical polishing on the film layer until the reducing ions Fe 2+ on the surface of the film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0174] The obtained blackened single-crystal piezoelectric composite film successively includes a blackened single-crystal film layer, a silicon dioxide layer, and a single-crystal silicon layer, wherein the material of the single-crystal film layer is single-crystal lithium niobate.

[0175] Example Nine

[0176] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example Nine includes the following steps:

[0177] ① Prepare a 200-μm silicon wafer and a 200-μm lithium niobate wafer. Fix the silicon wafer or lithium niobate on the porous ceramic chuck of a polishing device respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a lithium niobate wafer after blackening treatment.

[0178] ② Inject H into the lithium niobate wafer after the treatment in step ① by a lift-off ion implantation method + , so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a film layer starting from the injection surface. The injected H + is distributed in the separation layer to obtain an implanted wafer of single-crystal lithium niobate.

[0179] Inject H by the stripping ion implantation method + When injecting, the injection dose parameters are as follows: the injection dose is 4×10 16 ions / cm 2 , the injection energy is 40 keV, and the injection depth is 287 nm.

[0180] ③ Fabricate a damaged layer of single-crystalline silicon with a thickness of 100 nm, which is the first isolation layer, by implanting argon ions on the cleaned silicon wafer using the ion implantation method.

[0181] ④ Fabricate a silicon dioxide layer on the first isolation layer using the LPCVD method, and then perform chemical mechanical polishing until the thickness is 100 nm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface, thus obtaining the second isolation layer.

[0182] ⑤ Bring the single-crystalline lithium niobate wafer injection sheet into contact with the silicon dioxide layer and bond them using the direct bonding method to obtain a bonded body.

[0183] ⑥ Place the bonded body in an annealing furnace under a nitrogen atmosphere, keep it at 180 °C for 3 hours, the bonded body disconnects and separates at the separation layer, and then anneal it at 300 °C for 3 hours to obtain a single-crystalline piezoelectric composite film.

[0184] ⑦ Inject Zn into the thin film layer on the single-crystalline piezoelectric composite film processed in step ⑥ using the reducing ion implantation method 2+ , and the injected Zn 2+ ions are distributed on the surface of the thin film layer; then, place it in a blackening furnace, under a nitrogen atmosphere, keep it at 530 °C for 2 hours, and the injected Zn 2+ undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystalline piezoelectric composite film.

[0185] When injecting Zn using the reducing ion implantation method 2+ , the injection dose parameters are as follows: the injection dose is 1.5×10 16 ions / cm 2 , the injection energy is 130 keV, and the depth of injecting Zn 2+ into the surface of the thin film layer is 63 nm.

[0186] ⑧ Fix the blackened single-crystalline piezoelectric composite film on the porous ceramic chuck of the polishing equipment, perform chemical mechanical polishing on the thin film layer until the reducing ions Zn 2+ on the surface of the thin film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0187] The obtained blackened single-crystalline piezoelectric composite film successively includes a blackened single-crystalline thin film layer, a silicon dioxide layer (the second isolation layer), a first isolation layer, and a single-crystalline silicon layer, where the material of the single-crystalline thin film layer is single-crystalline lithium niobate.

[0188] Example Ten

[0189] Example ten provides a method for preparing a blackened single-crystal piezoelectric composite film based on ion implantation, which includes the following steps:

[0190] ① Prepare a 500-μm silicon carbide wafer and a 500-μm lithium tantalate wafer. Fix the silicon carbide wafer or lithium tantalate on the porous ceramic chuck of the polishing equipment respectively, and perform chemical mechanical polishing to obtain a smooth surface. Then, perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium tantalate wafer is a lithium tantalate wafer after blackening treatment.

[0191] ② Use the stripping ion implantation method to implant nitrogen ions into the lithium tantalate wafer processed in step ①, so that the lithium tantalate wafer is sequentially divided into a residual layer, a separation layer, and a thin film layer starting from the implantation surface. The implanted nitrogen ions are distributed in the separation layer to obtain an implanted wafer of single-crystal lithium tantalate.

[0192] When using the stripping ion implantation method to implant nitrogen ions, the implantation dose parameters are: the implantation dose is 2×10 16 ions / cm 2 , the implantation energy is 400 keV, and the implantation depth is 492 nm.

[0193] ③ Use the PVD method to deposit 10-μm-thick amorphous silicon on the cleaned silicon carbide wafer as the first isolation layer.

[0194] ④ Use the LPCVD method to deposit a silicon dioxide layer on the first isolation layer, and then perform chemical mechanical polishing to a thickness of 10 μm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface to obtain the second isolation layer.

[0195] ⑤ Contact the implanted wafer of single-crystal lithium tantalate with the silicon dioxide layer and bond them using the direct bonding method to obtain a bonded body.

[0196] ⑥ Under a nitrogen atmosphere, place the bonded body in an annealing furnace, keep it at 280 °C for 4 hours, and the bonded body disconnects and separates at the separation layer. Then, anneal it at 500 °C for 4 hours to obtain a single-crystal piezoelectric composite film.

[0197] ⑦ Use the reductive ion implantation method to implant Cu 2+ into the thin film layer of the single-crystal piezoelectric composite film processed in step ⑥. The implanted Cu 2+ ions are distributed on the surface of the thin film layer; then, place it in a blackening furnace, and under a nitrogen atmosphere, keep it at 600 °C for 2 hours. The implanted Cu 2+ undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystal piezoelectric composite film.

[0198] When using the reductive ion implantation method to implant Cu 2+When the injection dose parameter is: the injection dose is 5×10 10 ions / cm 2 , the injection energy is 80 keV, and the injection depth is 35.7 nm.

[0199] ⑧ Fix the blackened single-crystal piezoelectric composite film on the porous ceramic suction cup of the polishing equipment, and perform chemical mechanical polishing on the film layer until the reducing ions Cu 2+ on the surface of the film layer are removed, and then perform RCA cleaning to obtain a clean surface.

[0200] The obtained blackened single-crystal piezoelectric composite film successively includes a blackened single-crystal film layer, a silicon dioxide layer (second isolation layer), a first isolation layer, and a silicon carbide layer, wherein the material of the single-crystal film layer is single-crystal lithium tantalate.

[0201] Example XI

[0202] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example XI includes the following steps:

[0203] ① Prepare a 200-μm silicon nitride wafer and a 250-μm lithium niobate wafer, fix the silicon nitride wafer or lithium niobate on the porous ceramic suction cup of the polishing equipment respectively, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a lithium niobate wafer after blackening treatment.

[0204] ② Use the stripping ion implantation method to implant oxygen ions into the lithium niobate wafer processed in step ①, so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a film layer from the implantation surface, and the implanted oxygen ions are distributed in the separation layer to obtain a single-crystal lithium niobate wafer implanted sheet.

[0205] When using the stripping ion implantation method to implant oxygen ions, the injection dose parameter is: the injection dose is 3×10 16 ions / cm 2 , the injection energy is 380 keV, and the injection depth is 534 nm.

[0206] ③ Deposit a 1-μm-thick polysilicon on the cleaned silicon nitride wafer by PECVD method as the first isolation layer.

[0207] ④ Deposit a silicon dioxide layer on the first isolation layer by thermal oxidation method, and then perform chemical mechanical polishing to a thickness of 1 μm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface to obtain the second isolation layer.

[0208] ⑤ Contact the single-crystal lithium niobate wafer implanted sheet with the silicon dioxide layer and bond them by direct bonding to obtain a bonded body.

[0209] ⑥In a nitrogen atmosphere, the bonded body is placed in an annealing furnace and kept at 200 °C for 2 hours. The bonded body disconnects and separates at the separation layer, and then is annealed at 350 °C for 4 hours to obtain a single-crystal piezoelectric composite thin film.

[0210] ⑦For the thin film layer on the single-crystal piezoelectric composite thin film treated in step ⑥, Mg is implanted by a reducing ion implantation method. 2+ , and the implanted Mg 2+ ions are distributed on the surface of the thin film layer; then, it is placed in a blackening furnace and kept at 500 °C for 3 hours in a nitrogen atmosphere. The implanted Mg 2+ undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystal piezoelectric composite thin film.

[0211] When implanting Mg by a reducing ion implantation method 2+ , the implantation dose parameters are: the implantation dose is 5×10 13 ions / cm 2 , the implantation energy is 20 keV, and the implantation depth is 26 nm.

[0212] ⑧The blackened single-crystal piezoelectric composite thin film is fixed on the porous ceramic chuck of a polishing device, and the thin film layer is subjected to chemical mechanical polishing treatment until the reducing ions Mg 2+ on the surface of the thin film layer are removed, and then RCA cleaning is performed to obtain a clean surface.

[0213] The obtained blackened single-crystal piezoelectric composite thin film successively includes a blackened single-crystal thin film layer, a silicon dioxide layer (second isolation layer), a first isolation layer, and a silicon nitride layer, wherein the material of the single-crystal thin film layer is single-crystal lithium niobate.

[0214] Example Twelve

[0215] A preparation method of a blackened single-crystal piezoelectric composite thin film based on ion implantation provided by Example Twelve includes the following steps:

[0216] ①Prepare a 300-μm silicon wafer and a 400-μm lithium niobate wafer. Fix the silicon wafer or lithium niobate on the porous ceramic chuck of a polishing device respectively, perform chemical mechanical polishing treatment to obtain a smooth surface, and then perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a lithium niobate wafer after blackening treatment.

[0217] ②For the lithium niobate wafer treated in step ①, argon ions are implanted by a lift-off ion implantation method, so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the implantation surface. The implanted argon ions are distributed in the separation layer to obtain a single-crystal lithium niobate wafer implanted sheet.

[0218] When implanting argon ions by a lift-off ion implantation method, the implantation dose parameters are: the implantation dose is 4×10 16ions / cm 2 , with an implantation energy of 400 keV and an implantation depth of 285 nm.

[0219] ③ On the cleaned silicon wafer, amorphous silicon with a thickness of 500 nm is fabricated by PVD as the first isolation layer.

[0220] ④ On the first isolation layer, a silicon dioxide layer is fabricated by PECVD, and then chemically mechanically polished to a thickness of 5 μm to obtain a smooth surface, and RCA cleaned to obtain a clean surface, thus obtaining the second isolation layer.

[0221] ⑤ The single-crystal lithium niobate wafer injection piece is brought into contact with the silicon dioxide layer and bonded by direct bonding to obtain a bonded body.

[0222] ⑥ In a nitrogen atmosphere, the bonded body is placed in an annealing furnace and held at 220 °C for 3 hours. The bonded body is separated at the separation layer, and then annealed at 450 °C for 4 hours to obtain a single-crystal piezoelectric composite film.

[0223] ⑦ For the thin film layer on the single-crystal piezoelectric composite film treated in step ⑥, Zn is implanted by the reductive ion implantation method 2+ , and the implanted Zn 2+ ions are distributed on the surface of the thin film layer; then, it is placed in a blackening furnace and held at 530 °C for 4 hours in a nitrogen atmosphere. The implanted Zn 2+ undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystal piezoelectric composite film.

[0224] When Zn is implanted by the reductive ion implantation method 2+ , the implantation dose parameters are: the implantation dose is 1.5×10 16 ions / cm 2 , the implantation energy is 130 keV, and the depth of injecting Zn 2+ into the surface of the thin film layer is 63 nm.

[0225] ⑧ The blackened single-crystal piezoelectric composite film is fixed on the porous ceramic chuck of the polishing equipment, and the thin film layer is chemically mechanically polished until the reductive ions Zn 2+ on the surface of the thin film layer are removed, and then RCA cleaned to obtain a clean surface.

[0226] The obtained blackened single-crystal piezoelectric composite film successively includes a blackened single-crystal thin film layer, a silicon dioxide layer (the second isolation layer), a first isolation layer, and a single-crystalline silicon layer, wherein the material of the single-crystal thin film layer is single-crystal lithium niobate.

[0227] Example XIII

[0228] A preparation method of a blackened single-crystal piezoelectric composite film based on ion implantation provided by Example XIII includes the following steps:

[0229] ① Prepare a 410-μm silicon carbide wafer and a 300-μm lithium niobate wafer. Fix the silicon carbide wafer or lithium niobate on the porous ceramic chuck of the polishing equipment respectively, and perform chemical mechanical polishing to obtain a smooth surface. Then, perform semiconductor RCA cleaning on the two wafers to obtain a clean surface. Among them, the lithium niobate wafer is a lithium niobate wafer after blackening treatment.

[0230] ② Inject helium ions into the lithium niobate wafer processed in step ① by the stripping ion implantation method, so that the lithium niobate wafer is successively divided into a residual layer, a separation layer, and a thin film layer starting from the injection surface. The injected helium ions are distributed in the separation layer to obtain a single-crystalline lithium niobate wafer injection sheet.

[0231] When injecting helium ions by the stripping ion implantation method, the injection dose parameters are: the injection dose is 3×10 16 ions / cm 2 , the injection energy is 225 keV, and the injection depth is 780 nm.

[0232] ③ Inject argon ions into the cleaned silicon carbide wafer by the ion implantation method to fabricate a damaged layer of single-crystalline silicon as the first isolation layer, and the thickness of the first isolation layer is 5 μm.

[0233] ④ Fabricate a silicon dioxide layer on the first isolation layer by PECVD method, and then perform chemical mechanical polishing to a thickness of 500 nm to obtain a smooth surface, and perform RCA cleaning to obtain a clean surface to obtain the second isolation layer.

[0234] ⑤ Contact the single-crystalline lithium niobate wafer injection sheet with the silicon dioxide layer and bond them by the direct bonding method to obtain a bonded body.

[0235] ⑥ Under a nitrogen atmosphere, put the bonded body into an annealing furnace, keep it at 240 °C for 2 hours, the bonded body disconnects and separates at the separation layer, and then anneal at 350 °C for 5 hours to obtain a single-crystalline piezoelectric composite film.

[0236] ⑦ Inject Cu 2+ into the thin film layer of the single-crystalline piezoelectric composite film processed in step ⑥ by the reducing ion implantation method. The injected Cu 2+ ions are distributed on the surface of the thin film layer; then, put it into a blackening furnace, under a nitrogen atmosphere, keep it at 550 °C for 3 hours, and the injected Cu 2+ undergoes a blackening reduction reaction in the thin film layer to obtain a blackened single-crystalline piezoelectric composite film.

[0237] When injecting Cu 2+ by the reducing ion implantation method, the injection dose parameters are: the injection dose is 5×10 10 ions / cm 2, the implanted energy is 100 keV, and the implantation depth is 52.7 nm.

[0238] ⑧ Fix the blackened single-crystal piezoelectric composite film on the porous ceramic suction cup of the polishing equipment, and perform chemical mechanical polishing on the film layer until the reducing ions Cu on the surface of the film layer are removed, and then perform RCA cleaning to obtain a clean surface. 2+ removed, and then RCA cleaning is performed to obtain a clean surface.

[0239] The obtained blackened single-crystal piezoelectric composite film sequentially includes a blackened single-crystal film layer, a silicon dioxide layer (second isolation layer), a first isolation layer, and a silicon carbide layer, wherein the material of the single-crystal film layer is single-crystal lithium niobate.

[0240] In this specification, the same or similar parts between various embodiments can be referred to each other. In particular, the embodiments corresponding to the blackened single-crystal piezoelectric composite film can be referred to the part of the preparation method of the blackened single-crystal piezoelectric composite film based on ion implantation.

[0241] The present application has been described in detail above in conjunction with specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art understand that without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements can be made to the technical solutions and their implementation manners of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

Claims

1. A preparation method of a blackened single crystal piezoelectric composite film based on ion implantation, characterized in that, Including: Prepare a first wafer and a substrate, wherein the first wafer is a lithium niobate wafer or a lithium tantalum oxide wafer; Inject a first ion into the first wafer, and sequentially divide the first wafer into a residual layer, a separation layer, and a thin film layer; Bond the first wafer to the substrate to obtain a bonded body; Heat-treat the bonded body to separate the residual layer from the thin film layer to obtain a single-crystal piezoelectric composite film; Wherein, after injecting the first ion into the first wafer and before obtaining the bonded body, a second ion is injected into the thin film layer, the second ion is a hydrogen ion, and the injection dose and injection energy of the second ion are less than the injection dose and injection energy of the first ion; or, after obtaining the single-crystal piezoelectric composite film, a second ion is injected onto the surface of the thin film layer, and the second ion is a reducing metal ion; Perform blackening reduction heat treatment on the single-crystal piezoelectric composite film to obtain a blackened single-crystal piezoelectric composite film; Polish the surface of the thin film layer in the blackened single-crystal piezoelectric composite film.

2. The preparation method according to claim 1, wherein Performing blackening reduction heat treatment on the single-crystal piezoelectric composite film includes: Keep the single-crystal piezoelectric composite film at 300-600 °C for 1-100 hours.

3. The preparation method according to claim 1, wherein The injection dose of the injected second ion is less than the critical injection dose, and the critical injection dose is the minimum injection dose that causes the thin film layer to delaminate.

4. The preparation method according to claim 1, characterized in that, When the second ion is a hydrogen ion, The implantation dose of the first ion is 2×10 16 ions / cm 2 -4×10 16 ions / cm 2 , and the implantation energy is 40 - 400 keV; The implantation dose of the second ion is 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the implantation energy is 15 - 390 keV.

5. The preparation method according to claim 1, characterized in that, When the second ion is a reducing metal ion, The implantation dose of the first ion is 2×10 16 ions / cm 2 -4×10 16 ions / cm 2 , and the implantation energy is 40 - 400 keV; The implantation dose of the second ion is 5×10 10 ions / cm 2 -1.5×10 16 ions / cm 2 , and the implantation energy is 20 - 130 keV.

6. The preparation method according to claim 1, characterized in that The preparation method further includes: Perform a cleaning treatment after polishing the surface of the thin film layer in the blackened single-crystal piezoelectric composite film.

7. The preparation method according to claim 1, wherein, The substrate is a single-layer substrate or a composite substrate.

8. A blackened single crystal piezoelectric composite film, characterized in that The blackened single-crystal piezoelectric composite film is prepared by the preparation method of the blackened single-crystal piezoelectric composite film based on ion implantation according to any one of claims 1-7.

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