CN105321806A - Composite single crystal thin film and method for manufacturing composite single crystal thin film - Google Patents

Abstract

The invention discloses a compound single crystal film and a method for manufacturing the compound single crystal film. The composite single crystal film comprises: a substrate; an optical isolation layer located on the substrate; a lithium niobate single crystal film or a lithium tantalate single crystal film located on the optical isolation layer; a silicon film located on the lithium niobate single crystal film Or lithium tantalate single crystal thin film. According to the compound single crystal thin film of the present invention, it has good effects such as nonlinear optics, acousto-optic, and electro-optic effects of lithium niobate or lithium tantalate materials, and also has the characteristics of mature processing technology of silicon materials, so the composite single crystal thin film of the present invention It can achieve better compatibility with the existing IC production process and has very broad industrial prospects. In addition, the method for manufacturing a composite single crystal thin film according to the present invention can realize stable and effective industrialized production.

Description

Composite single crystal thin film and method for manufacturing composite single crystal thin film

technical field

The invention relates to the technical field of semiconductor materials and photoelectric materials, in particular to a composite single crystal thin film and a method for manufacturing the composite single crystal thin film.

Background technique

Lithium niobate single crystal thin film has a wide range of applications in the fields of optical signal processing, information storage, and electronic devices due to its excellent electro-optic, acousto-optic, and nonlinear effects. It can be used as a substrate material and can be used to make high-frequency Optoelectronic devices and integrated optical devices with high bandwidth, high integration, large capacity, high sensitivity, low power consumption and stable performance, such as filters, waveguide modulators, optical waveguide switches, spatial light modulators, optical frequency doubling devices, infrared detectors, and ferroelectric memories. When the lithium niobate single crystal thin film is used as the device layer for processing (mainly using etching and other processes), due to the relatively strong chemical inertia of lithium niobate, it is difficult to etch, the processing is difficult, and the process is not mature enough. Lithium niobate is difficult to process The problem seriously hinders the development of lithium niobate devices.

SOI (Silicon-On-Insulator, silicon on insulating substrate) technology introduces a buried oxide layer (such as silicon dioxide) between the top silicon and the substrate silicon to form a silicon-on-insulator thin film. In the field of electronics, SOI materials have advantages that silicon bulk materials do not have: it can realize the dielectric isolation of components in integrated circuits, and eliminate the parasitic latch effect in bulk silicon CMOS circuits; and integrated circuits made of this material The circuit also has the advantages of small parasitic capacitance, high integration density, fast speed, simple process, and is especially suitable for low-voltage and low-power consumption circuits. In the optical field, SOI is an important substrate material, which is mainly used to prepare integrated optical devices such as optical switches and optical modulators. The basic structure of these devices is an optical waveguide, which uses the principle of total reflection of light to confine light to be transmitted in the optical waveguide, which can facilitate the control of the transmission path of light. The processing technology of silicon material is very mature. For example, the etching process of silicon material is very mature, and very fine lines can be etched. At present, integrated optical devices using SOI as substrate materials have been industrialized. However, due to the weak nonlinear optical effect of the silicon material itself, its electro-optic, acousto-optic, and pyroelectric effects are also very weak, which limits its application in the field of optoelectronics.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a composite single crystal thin film and a method for manufacturing the composite single crystal thin film.

According to one aspect of the present invention, a composite single crystal thin film is provided, and the composite single crystal thin film includes: a substrate; an optical isolation layer positioned on the substrate; a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film positioned on the On an optical isolation layer; a silicon thin film on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film.

According to an exemplary embodiment of the present invention, the composite single crystal thin film may further include: another optical isolation layer located between the lithium niobate single crystal thin film or lithium tantalate single crystal thin film and the silicon thin film.

According to an exemplary embodiment of the present invention, the optical isolation layer may be a silicon dioxide layer, and the substrate may be a silicon substrate.

According to an exemplary embodiment of the present invention, the thickness of the substrate may be 10 μm-2000 μm, the thickness of the optical isolation layer may be 5 nm-10 μm, and the thickness of the lithium niobate single crystal thin film or lithium tantalate single crystal thin film may be 5 nm-50 μm , the thickness of the silicon thin film can be 5nm-50μm.

According to another aspect of the present invention, there is provided a method of manufacturing a composite single crystal thin film, the method comprising: preparing a substrate covered with an optical isolation layer; Lithium oxide single crystal thin film or lithium tantalate single crystal thin film; silicon thin film is formed on lithium niobate single crystal thin film or lithium tantalate single crystal thin film.

According to an exemplary embodiment of the present invention, the step of forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film may include: contacting a lithium niobate wafer or a lithium tantalate wafer with an optical isolation layer, and then using a wafer bonding method to Lithium niobate wafer or lithium tantalate wafer is bonded to the optical isolation layer; the surface of the lithium niobate wafer or lithium tantalate wafer facing away from the optical isolation layer is ground and then surface polished to form a lithium niobate single crystal thin film or lithium tantalate single crystal thin film.

According to an exemplary embodiment of the present invention, the step of forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film may include: implanting ions into a lithium niobate wafer or a lithium tantalate wafer by an ion implantation method, thereby An implanted layer, a separation layer, and a residual layer are formed in a lithium wafer or a lithium tantalate wafer, wherein the separation layer is located between the implanted layer and the residual layer, and the implanted ions are distributed in the separation layer; the implanted layer is in contact with the optical isolation layer , and then use the wafer bonding method to bond the lithium niobate wafer or lithium tantalate wafer with the optical isolation layer to form a bonded body; heat the bonded body to separate the injection layer from the remaining layer; polish the surface of the injection layer, Thereby forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film.

According to an exemplary embodiment of the present invention, the step of forming a silicon thin film may include: contacting the silicon wafer with a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film, and then bonding the silicon wafer to the lithium niobate single crystal thin film by wafer bonding. Thin film or lithium tantalate single crystal thin film bonding; the surface of the silicon wafer facing away from the lithium niobate single crystal thin film or lithium tantalate single crystal thin film is ground and then polished to form a silicon thin film.

According to an exemplary embodiment of the present invention, the step of forming the silicon thin film may include: implanting ions into the silicon wafer by ion implantation, thereby forming an implanted layer, a separation layer, and a residue layer in the silicon wafer, wherein the separation layer is located at the implanted Between the layer and the remaining layer, the implanted ions are distributed in the separation layer; the implanted layer is in contact with the lithium niobate single crystal thin film or lithium tantalate single crystal thin film, and then the silicon wafer and the lithium niobate single crystal thin film are bonded by wafer bonding. Thin films or lithium tantalate single crystal thin films are bonded to form a bonded body; the bonded body is heated to separate the injection layer from the rest of the material layer; the surface of the injection layer is polished to form a silicon thin film.

According to an exemplary embodiment of the present invention, the step of forming a silicon thin film may include: contacting the silicon thin film layer of the SOI wafer with a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film, and then using a wafer bonding method to bond the SOI wafer to the niobium niobate single crystal thin film. Lithium oxide single crystal thin film or lithium tantalate single crystal thin film bonding; Grinding or etching the silicon substrate of the SOI wafer to remove the silicon substrate and expose the silicon dioxide layer of the SOI wafer; Polishing or etching is performed to remove the silicon dioxide layer and expose the silicon thin film layer, thereby forming a silicon thin film on the lithium niobate single crystal thin film or lithium tantalate single crystal thin film.

As mentioned above, the composite single crystal film according to the present invention possesses good effects such as nonlinear optics, acousto-optic, and electro-optic effects of lithium niobate or lithium tantalate materials, and also possesses the characteristics of mature processing technology of silicon materials, so the present invention Composite single crystal thin films can achieve better compatibility with existing IC production processes and have very broad industrial prospects. In addition, the method for manufacturing a composite single crystal thin film according to the present invention can realize stable and effective industrialized production.

Description of drawings

These and/or other aspects will become clear and easier to understand through the following description of embodiments in conjunction with the accompanying drawings, in which:

1 is a schematic diagram showing the structure of a composite single crystal thin film according to an exemplary embodiment of the present invention;

FIG. 2 is a flowchart illustrating a method of manufacturing a composite single crystal thin film according to an exemplary embodiment of the present invention.

detailed description

Embodiments of the invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. However, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will provide Those of ordinary skill in the art fully convey the concept of the embodiments of the present invention. In the following detailed description, numerous specific details are set forth by way of example in order to provide a thorough understanding of the relevant teachings. It will be apparent, however, to one skilled in the art that the present teachings may be practiced without such details. In other instances, well-known methods, procedures, and components have been described at a relatively high level and without detail in order to avoid unnecessarily obscuring aspects of the present teachings. The same reference numerals in the drawings denote the same elements, and thus their descriptions will not be repeated. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.

The invention will now be described more fully hereinafter with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the structure of a composite single crystal thin film according to an exemplary embodiment of the present invention.

Referring to FIG. 1 , a composite single crystal thin film 100 according to an exemplary embodiment of the present invention includes: a substrate 110; an optical isolation layer 120 located on the substrate 110; a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film 130, It is located on the optical isolation layer 120 ; the silicon thin film 140 is located on the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film 130 .

The substrate 110 of the composite single crystal thin film 100 according to the present invention mainly functions to support the thin film or member thereon. According to an exemplary embodiment of the present invention, since silicon has the characteristics of large yield, low price, easy processing, and compatibility with existing semiconductor processes, the substrate 110 can be made of silicon material, however, the present invention is not limited thereto, and can be Select other suitable materials to make. According to an exemplary embodiment of the present invention, the thickness of the substrate 110 may be 10 μm-2000 μm, preferably, may be 100 μm-1000 μm.

The optical isolation layer 120 is used to separate the lithium niobate single crystal thin film or lithium tantalate single crystal thin film located thereon from the substrate 110 . Since the refractive index of the substrate 110 such as silicon is greater than that of a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film, silicon dioxide can be used to make the optical isolation layer 120, so that the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film The lithium tantalate single crystal thin film is separated from the substrate, so that the light field of the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film is not coupled into the substrate by mistake. According to an exemplary embodiment of the present invention, the thickness of the optical isolation layer 120 may be 5 nm-10 μm, preferably, may be 10 nm-3 μm. In addition, when light is required to enter the substrate 110, the thickness of the optical isolation layer can be reduced, or the optical isolation layer can even be eliminated.

The lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 is one of the important components of the composite single crystal thin film 100 . The thickness of the lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 can be determined according to the application, for example, 5 nm-50 μm or 10 nm-10 μm.

The silicon thin film 140 is located on the lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 , and forms an important part of the composite single crystal thin film 100 together with the lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 . The thickness of the silicon thin film 140 can be determined according to the application, for example, 5nm-50μm or 5nm-20μm.

According to an exemplary embodiment of the present invention, the composite single crystal thin film 100 of the present invention may also include another optical isolation layer (not shown) between the lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 and the silicon thin film 140 out). The function and material of the optical isolation layer are the same or substantially the same as those of the optical isolation layer 120 located between the substrate 110 and the lithium niobate single crystal thin film or lithium tantalate single crystal thin film 130 , so details will not be described here.

A method of manufacturing a composite single crystal thin film according to an exemplary embodiment of the present invention will be described in detail below with reference to FIG. 2 .

FIG. 2 is a flowchart illustrating a method of manufacturing a composite single crystal thin film according to an exemplary embodiment of the present invention.

Referring to FIG. 2 , the method for manufacturing a composite single crystal thin film of the present invention includes: preparing a substrate covered with an optical isolation layer; forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film; forming a silicon thin film.

Specifically, in the step of preparing a substrate covered with an optical isolation layer, the substrate can be made of silicon, and the optical isolation layer can be made of silicon dioxide, but the present invention is not limited thereto, and any suitable material can be used Made substrate and optical isolation layer. In an exemplary embodiment of the present invention, the thickness of the substrate may be 10 μm-2000 μm or 100 μm-1000 μm, and the thickness of the optical isolation layer may be 5 nm-10 μm or 10 nm-3 μm.

In the step of forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film, a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film can be formed on the optical isolation layer by the following process: firstly make a lithium niobate wafer or The lithium tantalate wafer is in contact with the optical isolation layer, and then the lithium niobate wafer or lithium tantalate wafer and the optical isolation layer are bonded together by wafer bonding, and then the back-to-back optical isolation of the lithium niobate wafer or lithium tantalate wafer The surface of the layer is ground and then polished to form a lithium niobate single crystal film or a lithium tantalate single crystal film on the optical isolation layer. Due to the characteristics of grinding, the thickness of lithium niobate single crystal thin film or lithium tantalate single crystal thin film produced according to this process is generally above 1 μm.

In addition, according to an exemplary embodiment of the present invention, the following process may also be used to form a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film on the optical isolation layer.

Firstly, using the ion implantation method, ions (which can be molecular ions) are implanted against the surface of the lithium niobate wafer or lithium tantalate wafer to form a separation layer, which divides the lithium niobate wafer or lithium tantalate wafer into most parts. The region through which the implanted ions pass (may be called the implanted layer) and the region where most of the implanted ions do not pass through (can be called the residual layer). The thickness of the implanted layer is determined by the energy of ion implantation, the greater the energy, the greater the thickness of the implanted layer.

Next, make the injection layer contact the optical isolation layer, and bond the lithium niobate wafer or lithium tantalate wafer and the optical isolation layer together by wafer bonding to form a bonded body.

Then, the bonded body is heated to separate the injection layer and the rest layer.

Finally, the surface of the injection layer is polished, so as to form a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film on the optical isolation layer.

In addition, in order to eliminate the damage caused by ion implantation to lithium niobate single crystal thin film or lithium tantalate single crystal thin film, the lithium niobate single crystal thin film or lithium tantalate single crystal thin film can be annealed after heating the bonding body .

Due to the characteristics of ion implantation, the thickness of lithium niobate single crystal film or lithium tantalate single crystal film produced according to this process is generally below 3 μm.

In the step of forming the silicon thin film, the silicon thin film can be formed on the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film by the following process: first, the silicon wafer is contacted with the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film , using a wafer bonding method to bond the silicon wafer with a lithium niobate single crystal film or a lithium tantalate single crystal film; then grind the surface of the silicon wafer facing away from the lithium niobate single crystal film or lithium tantalate single crystal film, Afterwards, the surface is polished to form a silicon thin film on the lithium niobate single crystal thin film or lithium tantalate single crystal thin film. Due to the characteristics of grinding, the thickness of the silicon film produced according to this process is generally above 1 μm.

In addition, according to an exemplary embodiment of the present invention, the following process may also be used to form a silicon thin film on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film.

First, ion implantation is used to implant ions (which can be molecular ions) against the surface of the silicon wafer to form a separation layer. The separation layer divides the silicon wafer into an area through which most of the implanted ions pass (which can be called an implanted layer) and a silicon wafer. The region where most of the implanted ions do not pass through (may be referred to as the remaining mass layer). The thickness of the implanted layer is determined by the energy of ion implantation, the greater the energy, the greater the thickness of the implanted layer.

Next, the implanted layer is brought into contact with the lithium niobate single crystal thin film or lithium tantalate single crystal thin film, and the silicon chip is bonded to the lithium niobate single crystal thin film or lithium tantalate single crystal thin film by wafer bonding to form a bonded body. .

Then, the bonded body is heated to separate the injection layer and the rest layer.

The injection layer is surface polished to form a silicon thin film on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film.

In addition, in order to eliminate the damage to the silicon film caused by the ion implantation, the silicon film can be annealed after heating the bonding body.

Due to the characteristics of ion implantation, the thickness of the silicon film made according to this process is generally below 3 μm.

In addition, according to an exemplary embodiment of the present invention, the following process may also be used to form a silicon thin film on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film.

Firstly, the silicon thin film layer of the SOI wafer is contacted with the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film, and the SOI wafer is bonded to the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film by wafer bonding.

Then, the silicon substrate in the SOI wafer is ground or etched to remove the silicon substrate in the SOI wafer and expose the silicon dioxide layer in the SOI wafer.

Next, the exposed silicon dioxide layer is polished or etched to remove the silicon dioxide layer in the SOI wafer and expose the silicon thin film layer in the SOI wafer, so that the lithium niobate single crystal thin film or lithium tantalate single crystal thin film A silicon film is formed on it.

In summary, the present invention integrates lithium niobate or lithium tantalate with a single crystal structure and silicon with a single crystal structure, so that the manufactured composite single crystal film has a four-layer structure of molecular-level contact, and each The thickness of the layer film can be adjusted within a wide range. Moreover, the composite single crystal thin film according to the present invention possesses good effects such as nonlinear optics, acousto-optic, and electro-optic effects of lithium niobate or lithium tantalate materials, and also possesses the characteristics of mature processing technology of silicon materials, which can realize light transmission between silicon thin films and silicon thin films. Conversion between lithium niobate single crystal thin film or lithium tantalate single crystal thin film. In addition, because the composite single crystal film of the present invention still has the characteristics of lithium niobate single crystal film or lithium tantalate single crystal film, it can be better compatible with the existing IC production process, so that it can produce , new features, excellent indicators of new optoelectronic devices.

In addition, the method for manufacturing a composite single crystal thin film according to the present invention can realize stable and effective industrialized production.

The specific process of manufacturing the composite single crystal thin film of the present invention will be described below by taking the lithium niobate single crystal thin film as an example.

Example 1

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 2 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; the ion implantation method is used to implant helium ions (He ¹⁺ and/or He ²⁺ ) into the lithium niobate wafer, the helium ion implantation energy is 250keV, and the dose is 4×10 ¹⁶ ions/cm ² .

Using the direct bonding method, the implanted surface of the lithium niobate wafer after the implantation is bonded with the silicon dioxide layer on the single crystal silicon substrate to form a bonded body; the bonded body is placed in an autoclave and filled with nitrogen ( N ₂ ), the pressure was kept at 200bar, and then the temperature was raised to 350°C and kept for 10 hours. During this heating process, the lithium niobate wafer was separated at the position where the helium ions stayed; then it was lowered to room temperature, and the wafer was taken out after releasing the pressure. The thickness of the lithium niobate single crystal thin film is about 0.83μm; the lithium niobate single crystal thin film is heated under normal pressure, the surrounding atmosphere is oxygen (O ₂ ), and the temperature is 300°C-800°C. This annealing process is used to eliminate ion implantation Damage caused in the lithium niobate single crystal thin film; then the surface of the lithium niobate single crystal thin film is polished to obtain a three-layer structure with a thickness of 0.5 μm lithium niobate single crystal thin film.

Single crystal silicon wafers are provided; hydrogen ions are implanted into single crystal silicon wafers by ion implantation method, the hydrogen ion implantation energy is 50keV, and the dose is 4×10 ¹⁷ ions/cm ² .

At room temperature, use the direct bonding method to bond the implanted surface of the implanted single crystal silicon wafer and the surface of the lithium niobate single crystal thin film together to obtain a bonded body; Next, heat the bonding body for 10 hours. During the heating process, the silicon wafer is separated at the position where the hydrogen ions stay, and the separated silicon film remains on the surface of the lithium niobate single crystal film. The thickness of the silicon film is about 1 μm; The surface of the film is polished to obtain a composite single crystal film product.

Example 2

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 2 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; at room temperature, the lithium niobate wafer is bonded to a silicon dioxide layer on a single crystal silicon substrate by direct bonding; the lithium niobate wafer is ground to 5 μm and then polished to 4 μm, Thus, a three-layer structure having a 4 μm thick lithium niobate single crystal thin film was obtained.

Single crystal silicon wafers are provided; hydrogen ions are implanted into the single crystal silicon wafers by the ion implantation method, the hydrogen ion implantation energy is 120keV, and the dose is 4×10 ¹⁷ ions/cm ² .

At room temperature, use the direct bonding method to bond the implanted surface of the implanted single crystal silicon wafer and the surface of the lithium niobate single crystal thin film together to obtain a bonded body; Next, heat the bonding body for 10 hours. During the heating process, the silicon wafer is separated at the position where the hydrogen ions stay, and the separated silicon film remains on the surface of the lithium niobate single crystal film. The thickness of the silicon film is about 1 μm; the covering The wafer with silicon film is annealed at 300°C-1000°C. This annealing process is used to eliminate the damage caused by ion implantation in the silicon film; the surface of the silicon film is polished to obtain a composite single crystal film product.

Example 3

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 2 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; the ion implantation method is used to implant helium ions (He ¹⁺ and/or He ²⁺ ) into the lithium niobate wafer, the helium ion implantation energy is 250keV, and the dose is 4×10 ¹⁶ ions/cm ² .

Using the direct bonding method, the implanted surface of the implanted lithium niobate wafer is bonded to the silicon dioxide layer on the single crystal silicon substrate to form a bonded body; the bonded body is heated to 250 ° C and kept for 10 hours, and then During this heating process, the lithium niobate wafer is separated at the position where the helium ions stay; then down to room temperature, the thickness of the lithium niobate single crystal film is about 0.83 μm; the lithium niobate single crystal film is heated, and the surrounding atmosphere is oxygen (O ₂ ), the temperature is 300°C-800°C, this annealing process is used to eliminate the damage caused by ion implantation in the lithium niobate film; then the surface of the lithium niobate single crystal film is polished to obtain a niobate with a thickness of 0.5 μm Three-layer structure of lithium single crystal thin film.

Provide monocrystalline silicon wafers; use the direct bonding method to bond the surfaces of monocrystalline silicon wafers and lithium niobate single crystal thin films together; grind the silicon wafers to 20 μm, and then polish them to 18 μm to obtain composite single crystal thin film products .

Example 4

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 0.2 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; at room temperature, the lithium niobate wafer is bonded to a silicon dioxide layer on a single crystal silicon substrate by direct bonding; the lithium niobate wafer is ground to 3 μm and then polished to 2 μm, Thus, a three-layer structure having a 2 μm thick lithium niobate single crystal thin film was obtained.

Provide monocrystalline silicon wafers; use the direct bonding method to bond the surfaces of monocrystalline silicon wafers and lithium niobate single crystal thin films together; grind the silicon wafers to 3 μm, and then polish them to 2 μm to obtain composite single crystal thin film products .

Example 5

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 5 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; the ion implantation method is used to implant helium ions (He ¹⁺ and/or He ²⁺ ) into the lithium niobate wafer, the helium ion implantation energy is 250keV, and the dose is 4×10 ¹⁶ ions/cm ² .

Using the direct bonding method, at room temperature, the implanted surface of the implanted lithium niobate wafer is bonded to the silicon dioxide layer on the single crystal silicon substrate to form a bonding body; the bonding body is heated to 250°C and kept For 10 hours, during this heating process, the lithium niobate wafer was separated at the position where the helium ions stayed; then cooled to room temperature, the thickness of the lithium niobate single crystal film was about 0.83 μm; the lithium niobate single crystal film was heated, and the surrounding atmosphere It is oxygen (O ₂ ), and the temperature is 300°C-800°C. This annealing process is used to eliminate the damage caused by ion implantation in the lithium niobate film; then the surface of the lithium niobate single crystal film is polished to obtain a 0.5μm Three-layer structure of thick lithium niobate single crystal thin film.

Provide SOI, at room temperature, use the wafer bonding method to bond SOI wafers to lithium niobate single crystal thin films or lithium tantalate single crystal thin films.

Etching the silicon substrate in the SOI wafer with 5% to 30% NaOH solution at a temperature of 30°C to 90°C to remove the silicon substrate in the SOI wafer and expose the silicon dioxide layer in the SOI wafer, When the concentration and temperature of NaOH solution are constant, the etching time is determined by the thickness of the silicon substrate.

Etching the exposed silicon dioxide layer with 1% to 30% HF solution to remove the silicon dioxide layer in the SOI wafer and expose the silicon thin film layer in the SOI wafer, so that the lithium niobate single crystal thin film or A silicon thin film is formed on a lithium tantalate single crystal thin film to obtain a composite single crystal thin film product.

Example 6

A single crystal silicon substrate covered with a silicon dioxide layer having a thickness of 2 μm and a single crystal silicon substrate having a thickness of 500 μm was prepared.

A lithium niobate wafer is provided; at room temperature, the lithium niobate wafer is bonded to a silicon dioxide layer on a single crystal silicon substrate by direct bonding; the lithium niobate wafer is ground to 10 μm and then polished to 8 μm, Thus, a three-layer structure having a lithium niobate single crystal thin film of 8 μm thick was obtained.

Provide SOI, at room temperature, use the wafer bonding method to bond SOI wafers to lithium niobate single crystal thin films or lithium tantalate single crystal thin films.

A single-side grinding method is used to remove the silicon substrate in the SOI wafer and expose the silicon dioxide layer in the SOI wafer.

Etching the exposed silicon dioxide layer with 1% to 30% HF solution to remove the silicon dioxide layer in the SOI wafer and expose the silicon thin film layer in the SOI wafer, so that the lithium niobate single crystal thin film or A silicon thin film is formed on a lithium tantalate single crystal thin film to obtain a composite single crystal thin film product.

In summary, the present invention bonds the lithium niobate material and the silicon material together to form a composite single crystal thin film material of lithium niobate and silicon, and the composite single crystal thin film material has good nonlinear optics, Acousto-optic, electro-optic and other effects also have the characteristics of mature silicon material processing technology, so the composite single crystal thin film of the present invention can achieve better compatibility with the existing IC production technology, and has very broad industrial prospects.

In addition, due to the relatively large difference in the physical and chemical properties of lithium niobate and silicon, there is currently no stable and effective process available for industrial production, and the method of manufacturing a composite single crystal film of lithium niobate and silicon The method can realize stable and effective industrialized production.

While the invention has been particularly shown and described with reference to exemplary embodiments thereof, those skilled in the art will understand that, without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents, Various changes in form and detail may be made herein without regard to scope. The embodiments should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

Claims (10)

1. A composite single crystal thin film is characterized in that, said composite single crystal thin film comprises: Substrate; an optical isolation layer on the substrate; Lithium niobate single crystal thin film or lithium tantalate single crystal thin film on the optical isolation layer; The silicon thin film is located on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film. 2. The composite single crystal thin film according to claim 1, characterized in that, the composite single crystal thin film also comprises: another optical optical film positioned between the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film and the silicon thin film. Isolation layer. 3. The composite single crystal thin film according to claim 1 or 2, characterized in that the optical isolation layer is a silicon dioxide layer, and the substrate is a silicon substrate. 4. The composite single crystal thin film according to claim 1, characterized in that the thickness of the substrate is 10 μm-2000 μm, the thickness of the optical isolation layer is 5 nm-10 μm, and the lithium niobate single crystal thin film or lithium tantalate single crystal thin film The thickness of the silicon film is 5nm-50μm, and the thickness of the silicon film is 5nm-50μm. 5. A method for manufacturing a composite single crystal thin film, characterized in that the method comprises the steps of: preparing a substrate covered with an optical isolation layer; forming a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film on the surface of the substrate covered with an optical isolation layer; A silicon thin film is formed on a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film. 6. method according to claim 5, is characterized in that, the step of forming lithium niobate single crystal film or lithium tantalate single crystal film comprises: Contacting the lithium niobate wafer or lithium tantalate wafer with the optical isolation layer, and then using the wafer bonding method to bond the lithium niobate wafer or lithium tantalate wafer to the optical isolation layer; The surface of the lithium niobate wafer or the lithium tantalate wafer facing away from the optical isolation layer is ground and then polished to form a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film. 7. method according to claim 5, is characterized in that, the step of forming lithium niobate single crystal thin film or lithium tantalate single crystal thin film comprises: Ions are implanted into a lithium niobate wafer or a lithium tantalate wafer by ion implantation, thereby forming an implanted layer, a separation layer and a residual layer in the lithium niobate wafer or a lithium tantalate wafer, wherein the separation layer is located between the implanted layer and the residual layer. Between the plasma layers, the implanted ions are distributed in the separation layer; making the injection layer contact the optical isolation layer, and then bonding the lithium niobate wafer or the lithium tantalate wafer to the optical isolation layer by a wafer bonding method to form a bonding body; Heating the bonding body to separate the injected layer from the remaining layer; The surface of the injection layer is polished to form a lithium niobate single crystal thin film or a lithium tantalate single crystal thin film. 8. The method according to claim 5, wherein the step of forming a silicon thin film comprises: Make the silicon wafer contact with lithium niobate single crystal thin film or lithium tantalate single crystal thin film, and then use the wafer bonding method to bond the silicon wafer with lithium niobate single crystal thin film or lithium tantalate single crystal thin film; The surface of the silicon wafer facing away from the lithium niobate single crystal film or the lithium tantalate single crystal film is ground, and then the surface is polished to form a silicon film. 9. The method according to claim 5, wherein the step of forming a silicon film comprises: Ions are implanted into the silicon wafer by an ion implantation method, thereby forming an implanted layer, a separation layer and a residual layer in the silicon wafer, wherein the separation layer is located between the implanted layer and the residual layer, and the implanted ions are distributed in the separation layer; The injection layer is in contact with the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film, and then the silicon chip is bonded to the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film by wafer bonding to form a bonded body; Heating the bonding body to separate the injected layer from the remaining layer; The surface of the injection layer is polished to form a silicon thin film. 10. The method according to claim 5, wherein the step of forming a silicon thin film comprises: Make the silicon thin film layer of the SOI wafer contact with the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film, and then use the wafer bonding method to bond the SOI wafer with the lithium niobate single crystal thin film or the lithium tantalate single crystal thin film; Grinding or etching the silicon substrate of the SOI wafer to remove the silicon substrate and expose the silicon dioxide layer of the SOI wafer; The exposed silicon dioxide layer is polished or etched to remove the silicon dioxide layer and expose the silicon thin film layer, thereby forming a silicon thin film on the lithium niobate single crystal thin film or lithium tantalate single crystal thin film.