Composite piezoelectric substrate and preparation method and application thereof

Abstract

The invention provides a composite piezoelectric substrate and a preparation method and application thereof. The composite piezoelectric substrate comprises a supporting substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing an X element and a piezoelectric material layer which are arranged in a stacked mode. The X element comprises a niobium element and / or a tantalum element. The Si-rich oxide layer, the amorphous Si layer and the X-element-containing silicon-lithium oxide layer are stacked between the SiO2 layer and the piezoelectric material layer and cooperate with one another, so that the bonding strength between the SiO2 layer and the piezoelectric material layer is enhanced, the risk of de-bonding of the composite piezoelectric substrate in the device manufacturing process is obviously reduced, and the reliability of the composite piezoelectric substrate is improved. And the manufacturing yield of the device is improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a composite piezoelectric substrate and a preparation method and application thereof. Background Art

[0002] The principle of the piezoelectric effect is that if pressure is applied to a piezoelectric material, it will generate a potential difference (called the positive piezoelectric effect), and vice versa, if voltage is applied, mechanical stress will be generated (called the inverse piezoelectric effect). If the pressure is a high-frequency vibration, high-frequency current will be generated. Therefore, piezoelectric materials have the function of converting and reversing between mechanical energy and electrical energy.

[0003] Lithium niobate and lithium tantalate are the most widely used new inorganic materials at present. They are excellent piezoelectric transducer materials. Lithium tantalate has excellent piezoelectric, ferroelectric, acousto-optic and electro-optic effects and is widely used in electronic communication devices such as resonators, filters, transducers, and high-frequency surface acoustic wave devices. Lithium niobate has good nonlinear optical properties and can be used as an optical waveguide material, or used to make medium and low frequency surface acoustic wave filters, high-power high-temperature resistant ultrasonic transducers, etc.

[0004] It is currently known that piezoelectric material substrates made of lithium niobate and lithium tannate have advantages over piezoelectric crystals such as high frequency, good temperature compensation performance, good stability, and low manufacturing cost. They have irreplaceable advantages in RF (radio frequency), fiber optic communications, and RF filters.

[0005] At present, piezoelectric thin films can be transferred to a foreign substrate through ion implantation, bonding or splitting to form a composite substrate. The existing composite substrate structure includes: a supporting substrate, a SiO2 layer and a piezoelectric material layer, wherein the SiO2 layer and the piezoelectric material layer are connected by bonding, which has the following problems: the bonding strength between the SiO2 layer and the piezoelectric material layer is insufficient, resulting in the risk of debonding of the composite substrate during the device manufacturing process, which reduces the yield of device manufacturing.

[0006] Therefore, how to effectively improve the bonding strength between the SiO2 layer and the piezoelectric material layer, thereby reducing the risk of debonding of the composite piezoelectric substrate during device manufacturing and improving the yield of device manufacturing, is a technical problem that needs to be solved urgently. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a composite piezoelectric substrate and a preparation method and application thereof. The present invention provides a Si-rich oxide layer, an amorphous Si layer and a silicon-lithium oxide layer containing the X element stacked between the SiO2 layer and the piezoelectric material layer, and the three cooperate with each other to jointly enhance the bonding strength between the SiO2 layer and the piezoelectric material layer, significantly reduce the risk of debonding of the composite piezoelectric substrate during the device manufacturing process, and improve the yield rate of device manufacturing.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a composite piezoelectric substrate, comprising a stacked support substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing an X element, and a piezoelectric material layer;

[0010] The X element includes niobium element and / or tantalum element.

[0011] The present invention stacks a Si-rich oxide layer, an amorphous Si layer and a silicon-lithium oxide layer containing the X element between the SiO2 layer and the piezoelectric material layer. The three cooperate with each other to jointly enhance the bonding strength between the SiO2 layer and the piezoelectric material layer, significantly reduce the risk of debonding of the composite piezoelectric substrate during the device manufacturing process, and improve the yield rate of device manufacturing.

[0012] Preferably, the diameter of the composite piezoelectric substrate is 2-8 inches, for example, it can be 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 7 inches or 8 inches.

[0013] Preferably, the material of the support substrate includes single crystal Si.

[0014] Preferably, the thickness of the support substrate is 100-1000 μm, for example, 100 μm, 300 μm, 500 μm, 700 μm or 900 μm.

[0015] Preferably, the thickness of the SiO2 layer is 0.1-1 μm, for example, 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm or 0.9 μm.

[0016] Preferably, the piezoelectric material layer is made of lithium niobate and / or lithium tantalate.

[0017] Preferably, the thickness of the piezoelectric material layer is 100-2000 nm, for example, 100 nm, 500 nm, 1000 nm, 1500 nm or 2000 nm.

[0018] Preferably, in the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is (0.5-1.5):1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, etc.

[0019] In the present invention, if the atomic ratio of oxygen atoms to silicon atoms in the Si-rich oxide layer is too small, the bonding strength between the SiO2 layer and the piezoelectric material layer is reduced; if the atomic ratio of oxygen atoms to silicon atoms in the Si-rich oxide layer is too large, the bonding strength between the SiO2 layer and the piezoelectric material layer is reduced.

[0020] Preferably, the thickness of the Si-rich oxide layer is 0.1-2 nm, for example, 0.1 nm, 0.5 nm, 1 nm, 1.5 nm or 2 nm.

[0021] Preferably, the thickness of the amorphous Si layer is 0.5-15 nm, for example, it may be 0.5 nm, 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, 11 nm, 13 nm or 15 nm.

[0022] In the present invention, if the thickness of the amorphous Si layer is too small, the bonding strength between the SiO2 layer and the piezoelectric material layer is reduced; if the thickness of the amorphous Si layer is too large, a longer preparation time is required, the cost is increased, and it is not conducive to cost reduction and efficiency improvement.

[0023] Preferably, in the silicon-lithium oxide layer containing the X element, the atomic content of silicon element is ≥ 0.05%, for example, it can be 0.05%, 0.1%, 0.3%, 0.5% or 1%, etc., preferably 0.05-1%.

[0024] In the present invention, if the atomic content of silicon element in the silicon-lithium oxide layer containing element X is too small, the bonding strength between the SiO2 layer and the piezoelectric material layer is reduced.

[0025] Preferably, in the silicon-lithium oxide layer containing element X, the atomic content of element X is 15-20%, for example, 15%, 16%, 17%, 18%, 19% or 20%.

[0026] Preferably, the thickness of the silicon-lithium oxide layer containing the X element is 0.1-2 nm, for example, 0.1 nm, 0.5 nm, 1 nm, 1.5 nm or 2 nm.

[0027] In a second aspect, the present invention provides a method for preparing the composite piezoelectric substrate as described in the first aspect, the preparation method comprising the following steps:

[0028] Providing a piezoelectric material substrate and a supporting substrate;

[0029] Performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer, and then preparing a bonding body by the first method or the second method;

[0030] The first method comprises: preparing a silicon-lithium oxide layer containing the X element on the ion-implanted surface of the piezoelectric material substrate; sequentially preparing a SiO2 layer, a Si-rich oxide layer and an amorphous Si layer on one surface of the support substrate; bonding the silicon-lithium oxide layer containing the X element to the amorphous Si layer;

[0031] The second method comprises: sequentially preparing a silicon lithium oxide layer containing an X element and an amorphous Si layer on the ion implantation surface of the piezoelectric material substrate; sequentially preparing a SiO2 layer and a Si-rich oxide layer on one surface of the supporting substrate; bonding the amorphous Si layer to the Si-rich oxide layer;

[0032] Performing heat treatment on the bonded body so that the bonded body is broken along the weakened layer to obtain a composite piezoelectric substrate and a piezoelectric material substrate to be recycled;

[0033] The X element includes niobium and / or tantalum.

[0034] It should be noted that the piezoelectric material substrate to be recycled can be used as a raw material again to continue preparing a composite piezoelectric substrate.

[0035] The present invention does not limit the preparation method of the SiO2 layer. Exemplarily, the preparation method of the SiO2 layer may be, for example, surface oxidation of a Si supporting substrate, electron beam sputtering deposition, or magnetron sputtering deposition.

[0036] Preferably, the ion implantation is performed using hydrogen ions and / or helium ions.

[0037] Preferably, the depth of the ion implantation is 0.3-2 μm, for example, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm or 2 μm.

[0038] Preferably, the steps of preparing the silicon-lithium oxide layer containing element X include:

[0039] The ion-implanted surface of the piezoelectric material substrate is subjected to particle irradiation and Si element sputtering deposition.

[0040] In the present invention, the purpose of particle irradiation is to remove dirt from the surface of the piezoelectric material substrate and improve its surface activity so as to enhance the bonding strength between the sputtered deposited Si element and the piezoelectric material.

[0041] Preferably, the particles in the particle irradiation are neutral particles. The present invention does not limit the type of the neutral particles, and exemplary neutral particles may be Ar, He or nitrogen.

[0042] Preferably, during the particle irradiation process, the acceleration voltage of the particle beam is 0.1-10 kV, for example, 0.1 kV, 0.5 kV, 1 kV, 3 kV, 5 kV, 7 kV or 9 kV.

[0043] Preferably, during the particle irradiation process, the current is 10-300 mA, for example, 10 mA, 50 mA, 100 mA, 150 mA, 200 mA, 250 mA or 300 mA.

[0044] Preferably, during the particle irradiation process, the irradiation time is 10-600 s, for example, it can be 10 s, 50 s, 100 s, 200 s, 300 s, 400 s, 500 s or 600 s.

[0045] It should be noted that Si element sputtering deposition refers to bombarding a Si material target with a high-energy particle beam, so that atoms in the target are sputtered out and deposited on the substrate surface to form a thin film.

[0046] Preferably, the Si element sputtering deposition method includes any one of magnetron sputtering deposition method, direct current sputtering deposition method, alternating current sputtering deposition method or reactive sputtering deposition method, or a combination of at least two thereof.

[0047] Preferably, the step of preparing the Si-rich oxide layer comprises:

[0048] The surface of the SiO2 layer that is away from the supporting substrate is irradiated with particles to form a Si-rich oxide layer.

[0049] Preferably, the preparation method of the amorphous Si layer includes any one of magnetron sputtering deposition method, direct current sputtering deposition method, alternating current sputtering deposition method or reactive sputtering deposition method, or a combination of at least two thereof.

[0050] Preferably, the bonding is performed in a vacuum environment, and the absolute pressure of the vacuum environment is ≤10 -3 Pa, for example, can be 10 -3 Pa, 5×10 -4 Pa, 1×10 -3 Pa, 5×10 -4 Pa or 1×10 -4 Pa et al.

[0051] Preferably, the bonding pressure is 1000-100000N, for example, it may be 1000N, 5000N, 10000N, 25000N, 50000N, 75000N or 100000N.

[0052] Preferably, the temperature of the heat treatment is 100-300°C, for example, 100°C, 150°C, 200°C, 250°C or 300°C.

[0053] Preferably, the constant temperature time of the heat treatment is 10-120 min, for example, it can be 10 min, 30 min, 50 min, 70 min, 90 min, 100 min or 120 min.

[0054] Preferably, the preparation method comprises the following steps:

[0055] (1) providing a piezoelectric material substrate and a supporting substrate, and then performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer;

[0056] Wherein, the ion implantation is performed using hydrogen ions and / or helium ions, and the depth of the ion implantation is 0.3-2 μm;

[0057] (2) Prepare the bonded body by method 1 or method 2:

[0058] The first method comprises: performing particle irradiation and Si element sputtering deposition on the ion implanted surface of the piezoelectric material substrate to form a silicon lithium oxide layer containing the X element; preparing a SiO2 layer on one surface of the supporting substrate, then performing particle irradiation on the surface of the SiO2 layer to form a Si-rich oxide layer, and then sputtering deposition of Si element on the surface of the Si-rich oxide layer to form an amorphous Si layer; and performing a vacuum at an absolute pressure of ≤10 -3 Pa, bonding the silicon lithium oxide layer containing the X element to the amorphous Si layer, the bonding pressure is 1000-100000N, and the bonding temperature is room temperature (the present invention does not limit the specific temperature of room temperature, for example, it can be 20±5°C, such as 15°C, 20°C or 25°C);

[0059] The second method comprises: performing particle irradiation and Si element sputtering deposition on the ion implanted surface of the piezoelectric material substrate to form a silicon-lithium oxide layer containing the element X, and then sputtering and depositing Si element on the surface of the silicon-lithium oxide layer containing the element X to form an amorphous Si layer; preparing a SiO2 layer on one surface of the supporting substrate, and then performing particle irradiation on the surface of the SiO2 layer to form a Si-rich oxide layer; at an absolute pressure of ≤10 -3 In a vacuum environment of 1.5 N Pa, the amorphous Si layer is bonded to the Si-rich oxide layer, the bonding pressure is 1000-100000 N, and the bonding temperature is room temperature;

[0060] Wherein, the X element includes niobium and / or tantalum. In the first and second methods, the particles for particle irradiation are all neutral particles. The specific parameters include:

[0061] The acceleration voltage of the particle beam is 0.1-10 kV, the current is 10-300 mA, and the irradiation time is 10-600 s;

[0062] (3) The bonded body is heat treated at 100-300° C. for 10-120 min, so that the bonded body is broken along the weakened layer, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate to be recycled.

[0063] In a third aspect, the present invention provides an application of the composite piezoelectric substrate as described in the first aspect, wherein the composite piezoelectric substrate is used to manufacture optoelectronic devices or acoustic wave devices.

[0064] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] The present invention stacks a Si-rich oxide layer, an amorphous Si layer and a silicon-lithium oxide layer containing the X element between the SiO2 layer and the piezoelectric material layer. The three cooperate with each other to jointly enhance the bonding strength between the SiO2 layer and the piezoelectric material layer, significantly reduce the risk of debonding of the composite piezoelectric substrate during the device manufacturing process, and improve the yield rate of device manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic diagram of the structure of the composite piezoelectric substrate provided in Example 1 of the present invention.

[0068] Figure 2 This is a process flow chart of the preparation method provided in Example 1 of the present invention.

[0069] Figure 3 This is a process flow chart of the preparation method provided in Example 2 of the present invention.

[0070] Among them, 1-support substrate; 2-SiO2 layer; 3-Si-rich oxide layer; 4-amorphous Si layer; 5-silicon lithium oxide layer containing X element; 6-piezoelectric material layer; 600-piezoelectric material substrate; 600'-piezoelectric material substrate to be recycled; 7-weakened layer. DETAILED DESCRIPTION

[0071] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0072] It should be noted that the room temperature below refers to 25°C.

[0073] Example 1

[0074] This embodiment provides a composite piezoelectric substrate, and its structural schematic diagram is as follows: Figure 1 As shown, the composite piezoelectric substrate includes a stacked support substrate 1, a SiO2 layer 2, a Si-rich oxide layer 3, an amorphous Si layer 4, a silicon-lithium oxide layer 5 containing niobium elements, and a piezoelectric material layer 6;

[0075] The diameter of the composite piezoelectric substrate is 5 inches, the material of the support substrate 1 is single crystal Si, the thickness of the support substrate 1 is 500 μm, the thickness of the SiO2 layer 2 is 0.5 μm, the material of the piezoelectric material layer 6 is lithium niobate, and the thickness of the piezoelectric material layer 6 is 1000 nm;

[0076] In the Si-rich oxide layer 3, the atomic ratio of oxygen atoms to silicon atoms is 1:1, and the thickness of the Si-rich oxide layer 3 is 1 nm;

[0077] The thickness of the amorphous Si layer 4 is 10 nm;

[0078] In the silicon-lithium oxide layer 5 containing niobium, the atomic content of silicon is 1%, the atomic content of niobium is 15%, and the thickness of the silicon-lithium oxide layer 5 containing niobium is 1 nm.

[0079] This embodiment also provides a method for preparing the composite piezoelectric substrate, and its process flow chart is as follows: Figure 2 As shown, the preparation method comprises the following steps:

[0080] (1) providing a piezoelectric material substrate 600 and a supporting substrate 1, and then performing ion implantation on a surface of the piezoelectric material substrate 600 to form a weakened layer 7;

[0081] The ion implantation is carried out using hydrogen ions, and the depth of the ion implantation is 1 μm;

[0082] (2) The bonded body is prepared by the following method:

[0083] Particle irradiation and Si element magnetron sputtering deposition are performed on the ion implantation surface of the piezoelectric material substrate 600 to form a silicon lithium oxide layer 5 containing niobium element; a SiO2 layer 2 is deposited on one surface of the support substrate 1 by magnetron sputtering, and then the surface of the SiO2 layer 2 is irradiated with particles to form a Si-rich oxide layer 3, and then Si element is sputtered and deposited on the surface of the Si-rich oxide layer 3 by magnetron sputtering deposition to form an amorphous Si layer 4; at an absolute pressure of 5×10 -3Pa, bonding the silicon-lithium oxide layer 5 containing niobium element to the amorphous Si layer 4, the bonding pressure is 5000N, and the bonding temperature is room temperature;

[0084] Among them, the particles used for particle irradiation are all Ar particles, and the specific parameters include:

[0085] The accelerating voltage of the particle beam was 5 kV, the current was 150 mA, and the irradiation time was 300 s;

[0086] (3) The bonded body is heat treated at 200° C. for 60 minutes, so that the bonded body is broken along the weakened layer 7, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate 600 ′ to be recycled. The piezoelectric material substrate 600 ′ to be recycled is reused in step (1) as a raw material.

[0087] Example 2

[0088] This embodiment provides a composite piezoelectric substrate, which includes a stacked support substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing niobium, and a piezoelectric material layer;

[0089] The diameter of the composite piezoelectric substrate is 5 inches, the material of the supporting substrate is single crystal Si, the thickness of the supporting substrate is 500 μm, the thickness of the SiO2 layer is 0.5 μm, the material of the piezoelectric material layer is lithium niobate, and the thickness of the piezoelectric material layer is 1000 nm;

[0090] In the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is 1:1, and the thickness of the Si-rich oxide layer is 1 nm;

[0091] The thickness of the amorphous Si layer is 10 nm;

[0092] In the silicon-lithium oxide layer containing niobium element, the atomic content of silicon element is 1%, the atomic content of niobium element is 15%, and the thickness of the silicon-lithium oxide layer containing niobium element is 1 nm.

[0093] This embodiment also provides a method for preparing the composite piezoelectric substrate, and its process flow chart is as follows: Figure 3 As shown, the preparation method comprises the following steps:

[0094] (1) providing a piezoelectric material substrate and a supporting substrate, and then performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer;

[0095] The ion implantation is carried out using hydrogen ions, and the depth of the ion implantation is 1 μm;

[0096] (2) The bonded body is prepared by the following method:

[0097] The ion-implanted surface of the piezoelectric material substrate is subjected to particle irradiation and Si element magnetron sputtering deposition to form a silicon-lithium oxide layer containing niobium element, and then Si element is magnetron sputtered on the surface of the silicon-lithium oxide layer containing niobium element to form an amorphous Si layer; a SiO2 layer is deposited on one surface of the supporting substrate by magnetron sputtering deposition, and then the surface of the SiO2 layer is subjected to particle irradiation to form a Si-rich oxide layer; at an absolute pressure of 5×10 -3 In a vacuum environment of 1.500 Å / s, the amorphous Si layer is bonded to the Si-rich oxide layer at a bonding pressure of 5000 N and a bonding temperature of room temperature;

[0098] Among them, the particles used for particle irradiation are all Ar particles, and the specific parameters include:

[0099] The accelerating voltage of the particle beam was 5 kV, the current was 150 mA, and the irradiation time was 300 s;

[0100] (3) The bonded body is heat treated at 200° C. for 60 minutes, so that the bonded body is broken along the weakened layer, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate to be recycled.

[0101] Example 3

[0102] This embodiment provides a composite piezoelectric substrate, which includes a stacked support substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing niobium, and a piezoelectric material layer;

[0103] The diameter of the composite piezoelectric substrate is 5 inches, the material of the supporting substrate is single crystal Si, the thickness of the supporting substrate is 500 μm, the thickness of the SiO2 layer is 0.1 μm, the material of the piezoelectric material layer is lithium tantalate, and the thickness of the piezoelectric material layer is 500 nm;

[0104] In the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is 0.5:1, and the thickness of the Si-rich oxide layer is 0.1 nm;

[0105] The thickness of the amorphous Si layer is 0.5 nm;

[0106] In the silicon-lithium oxide layer containing tantalum element, the atomic content of silicon element is 0.05%, the atomic content of tantalum element is 20%, and the thickness of the silicon-lithium oxide layer containing tantalum element is 0.1 nm.

[0107] This embodiment also provides a method for preparing the composite piezoelectric substrate, the method comprising the following steps:

[0108] (1) providing a piezoelectric material substrate and a supporting substrate, and then performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer;

[0109] Among them, the ion implantation is carried out using helium ions, and the depth of ion implantation is 0.3 μm;

[0110] (2) The bonded body is prepared by the following method:

[0111] Particle irradiation and Si element magnetron sputtering deposition are performed on the ion implantation surface of the piezoelectric material substrate to form a silicon lithium oxide layer containing tantalum element; a SiO2 layer is deposited on one surface of the support substrate by magnetron sputtering, and then the surface of the SiO2 layer is irradiated with particles to form a Si-rich oxide layer, and then Si element is sputtered and deposited on the surface of the Si-rich oxide layer by magnetron sputtering deposition to form an amorphous Si layer; at an absolute pressure of 5×10 -3 In a vacuum environment of 1.5 Pa, the silicon lithium oxide layer containing tantalum element is bonded to the amorphous Si layer, the bonding pressure is 1000N, and the bonding temperature is room temperature;

[0112] Among them, the particles used for particle irradiation are all Ar particles, and the specific parameters include:

[0113] The accelerating voltage of the particle beam was 1 kV, the current was 50 mA, and the irradiation time was 500 s;

[0114] (3) The bonded body is heat treated at 100° C. for 120 min, so that the bonded body is broken along the weakened layer, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate to be recycled.

[0115] Example 4

[0116] This embodiment provides a composite piezoelectric substrate, which includes a stacked support substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing niobium, and a piezoelectric material layer;

[0117] The diameter of the composite piezoelectric substrate is 5 inches, the material of the supporting substrate is single crystal Si, the thickness of the supporting substrate is 500 μm, the thickness of the SiO2 layer is 1 μm, the material of the piezoelectric material layer is lithium tantalate, and the thickness of the piezoelectric material layer is 2000 nm;

[0118] In the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is 1.5:1, and the thickness of the Si-rich oxide layer is 2 nm;

[0119] The thickness of the amorphous Si layer is 15 nm;

[0120] In the silicon-lithium oxide layer containing tantalum element, the atomic content of silicon element is 0.5%, the atomic content of tantalum element is 17.5%, and the thickness of the silicon-lithium oxide layer containing tantalum element is 2nm.

[0121] This embodiment also provides a method for preparing the composite piezoelectric substrate, the method comprising the following steps:

[0122] (1) providing a piezoelectric material substrate and a supporting substrate, and then performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer;

[0123] Among them, the ion implantation is carried out using helium ions, and the depth of ion implantation is 2 μm;

[0124] (2) The bonded body is prepared by the following method:

[0125] Particle irradiation and Si element magnetron sputtering deposition are performed on the ion implantation surface of the piezoelectric material substrate to form a silicon lithium oxide layer containing tantalum element; a SiO2 layer is deposited on one surface of the support substrate by magnetron sputtering, and then the surface of the SiO2 layer is irradiated with particles to form a Si-rich oxide layer, and then Si element is sputtered and deposited on the surface of the Si-rich oxide layer by magnetron sputtering deposition to form an amorphous Si layer; at an absolute pressure of 5×10 -3 Pa, bonding the tantalum-containing silicon lithium oxide layer to the amorphous Si layer, with a bonding pressure of 10000N and a bonding temperature of room temperature;

[0126] Among them, the particles used for particle irradiation are all Ar particles, and the specific parameters include:

[0127] The accelerating voltage of the particle beam was 10 kV, the current was 300 mA, and the irradiation time was 10 s;

[0128] (3) The bonded body is heat treated at 300° C. for 10 minutes, so that the bonded body is broken along the weakened layer, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate to be recycled.

[0129] Example 5

[0130] The difference between this embodiment and embodiment 1 is that in the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is 0.4:1.

[0131] The rest of the preparation methods and parameters were the same as those in Example 1.

[0132] Example 6

[0133] The difference between this embodiment and embodiment 1 is that in the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is 1.6:1.

[0134] The rest of the preparation methods and parameters were the same as those in Example 1.

[0135] Example 7

[0136] The difference between this embodiment and Embodiment 1 is that the thickness of the amorphous Si layer is 0.1 nm.

[0137] The rest of the preparation methods and parameters were the same as those in Example 1.

[0138] Example 8

[0139] The difference between this embodiment and embodiment 1 is that the thickness of the amorphous Si layer is 20 nm.

[0140] The rest of the preparation methods and parameters were the same as those in Example 1.

[0141] Example 9

[0142] The difference between this embodiment and embodiment 1 is that the atomic content of niobium in the silicon-lithium oxide layer containing niobium is 25%.

[0143] The rest of the preparation methods and parameters were the same as those in Example 1.

[0144] Comparative Example 1

[0145] The difference between this comparative example and Example 1 is that no Si-rich oxide layer is provided.

[0146] The rest of the preparation methods and parameters were the same as those in Example 1.

[0147] Comparative Example 2

[0148] The difference between this comparative example and Example 1 is that no amorphous Si layer is provided.

[0149] The rest of the preparation methods and parameters were the same as those in Example 1.

[0150] Comparative Example 3

[0151] The difference between this comparative example and Example 1 is that the silicon-lithium oxide layer containing niobium element is not provided.

[0152] The rest of the preparation methods and parameters were the same as those in Example 1.

[0153] Comparative Example 4

[0154] The difference between this comparative example and Example 1 is that no Si-rich oxide layer, no amorphous Si layer and no silicon-lithium oxide layer containing niobium element are provided.

[0155] The rest of the preparation methods and parameters were the same as those in Example 1.

[0156] Performance Testing

[0157] In the composite piezoelectric substrates prepared in the above-mentioned embodiments and comparative examples, the bonding strength between the SiO2 layer and the piezoelectric material layer was tested by a blade insertion method.

[0158] The test results are shown in Table 1.

[0159] Table 1

[0160]

[0161]

[0162] analyze:

[0163] It can be seen from the above table that the present invention stacks a Si-rich oxide layer, an amorphous Si layer and a silicon-lithium oxide layer containing the X element between the SiO2 layer and the piezoelectric material layer. The three cooperate with each other to jointly enhance the bonding strength between the SiO2 layer and the piezoelectric material layer, significantly reduce the risk of debonding of the composite piezoelectric substrate during the device manufacturing process, and improve the yield of device manufacturing.

[0164] It can be seen from Example 1 and Examples 5-6 that if the atomic ratio of oxygen atoms to silicon atoms in the Si-rich oxide layer is too small, the bonding strength between the SiO2 layer and the piezoelectric material layer will be reduced; if the atomic ratio of oxygen atoms to silicon atoms in the Si-rich oxide layer is too large, the bonding strength between the SiO2 layer and the piezoelectric material layer will be reduced.

[0165] It can be seen from Example 1 and Examples 7-8 that if the thickness of the amorphous Si layer is too small, the bonding strength between the SiO2 layer and the piezoelectric material layer will be reduced; if the thickness of the amorphous Si layer is too large, the bonding strength between the SiO2 layer and the piezoelectric material layer will be reduced, and a longer preparation time will be required, which will increase the cost and is not conducive to cost reduction and efficiency improvement.

[0166] It can be seen from Example 1 and Example 9 that if the atomic content of the niobium element in the silicon-lithium oxide layer containing the niobium element is too high, the bonding strength between the SiO2 layer and the piezoelectric material layer will be reduced.

[0167] It can be seen from Example 1 and Comparative Example 1 that if the Si-rich oxide layer is not provided, the bonding strength between the SiO2 layer and the piezoelectric material layer will be significantly reduced.

[0168] It can be seen from Example 1 and Comparative Example 2 that if the amorphous Si layer is not provided, the bonding strength between the SiO2 layer and the piezoelectric material layer will be significantly reduced.

[0169] It can be seen from Example 1 and Comparative Example 3 that if the silicon-lithium oxide layer containing niobium element is not provided, the bonding strength between the SiO2 layer and the piezoelectric material layer will be significantly reduced.

[0170] It can be seen from Example 1 and Comparative Example 4 that if the Si-rich oxide layer, the amorphous Si layer and the silicon-lithium oxide layer containing niobium are not provided, the bonding strength between the SiO2 layer and the piezoelectric material layer will be sharply reduced.

[0171] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A composite piezoelectric substrate, characterized in that: The composite piezoelectric substrate comprises a stacked support substrate, a SiO2 layer, a Si-rich oxide layer, an amorphous Si layer, a silicon-lithium oxide layer containing an X element, and a piezoelectric material layer; The X element includes niobium element and / or tantalum element.

2. The composite piezoelectric substrate according to claim 1, characterized in that The diameter of the composite piezoelectric substrate is 2-8 inches; Preferably, the material of the support substrate includes single crystal Si; Preferably, the thickness of the support substrate is 100-1000 μm; Preferably, the thickness of the SiO2 layer is 0.1-1 μm.

3. The composite piezoelectric substrate according to claim 1 or 2, characterized in that: The material of the piezoelectric material layer includes lithium niobate and / or lithium tantalate; Preferably, the thickness of the piezoelectric material layer is 100-2000 nm.

4. The composite piezoelectric substrate according to any one of claims 1 to 3, characterized in that: In the Si-rich oxide layer, the atomic ratio of oxygen atoms to silicon atoms is (0.5-1.5):1; Preferably, the thickness of the Si-rich oxide layer is 0.1-2 nm; Preferably, the thickness of the amorphous Si layer is 0.5-15 nm; Preferably, in the silicon-lithium oxide layer containing element X, the atomic content of silicon element is ≥ 0.05%, preferably 0.05-1%; Preferably, in the silicon-lithium oxide layer containing element X, the atomic content of element X is 15-20%; Preferably, the thickness of the silicon-lithium oxide layer containing the X element is 0.1-2 nm.

5. A method for preparing a composite piezoelectric substrate according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: Providing a piezoelectric material substrate and a supporting substrate; Performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer, and then preparing a bonding body by the first method or the second method; The first method comprises: preparing a silicon-lithium oxide layer containing the X element on the ion-implanted surface of the piezoelectric material substrate; sequentially preparing a SiO2 layer, a Si-rich oxide layer and an amorphous Si layer on one surface of the support substrate; bonding the silicon-lithium oxide layer containing the X element to the amorphous Si layer; The second method comprises: sequentially preparing a silicon lithium oxide layer containing an X element and an amorphous Si layer on the ion implantation surface of the piezoelectric material substrate; sequentially preparing a SiO2 layer and a Si-rich oxide layer on one surface of the supporting substrate; bonding the amorphous Si layer to the Si-rich oxide layer; Performing heat treatment on the bonded body so that the bonded body is broken along the weakened layer to obtain a composite piezoelectric substrate and a piezoelectric material substrate to be recycled; The X element includes niobium and / or tantalum.

6. The preparation method according to claim 5, characterized in that: The ion implantation is performed using hydrogen ions and / or helium ions; Preferably, the ion implantation depth is 0.3-2 μm.

7. The preparation method according to claim 5 or 6, characterized in that: The steps of preparing the silicon-lithium oxide layer containing the X element include: The ion implanted surface of the piezoelectric material substrate is subjected to particle irradiation and Si element sputtering deposition; Preferably, the Si element sputtering deposition method includes any one of magnetron sputtering deposition method, direct current sputtering deposition method, alternating current sputtering deposition method or reactive sputtering deposition method, or a combination of at least two thereof; Preferably, the step of preparing the Si-rich oxide layer comprises: The surface of the SiO2 layer away from the supporting substrate is irradiated with particles to form a Si-rich oxide layer; Preferably, the preparation method of the amorphous Si layer includes any one of magnetron sputtering deposition method, direct current sputtering deposition method, alternating current sputtering deposition method or reactive sputtering deposition method, or a combination of at least two thereof.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The bonding is performed in a vacuum environment, and the absolute pressure of the vacuum environment is ≤10 -3 Pa; Preferably, the bonding pressure is 1000-100000N; Preferably, the temperature of the heat treatment is 100-300°C; Preferably, the constant temperature time of the heat treatment is 10-120 min.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The preparation method comprises the following steps: (1) providing a piezoelectric material substrate and a supporting substrate, and then performing ion implantation on a surface of the piezoelectric material substrate to form a weakened layer; Wherein, the ion implantation is performed using hydrogen ions and / or helium ions, and the depth of the ion implantation is 0.3-2 μm; (2) Prepare the bonded body by method 1 or method 2: The first method comprises: performing particle irradiation and Si element sputtering deposition on the ion implanted surface of the piezoelectric material substrate to form a silicon lithium oxide layer containing the X element; preparing a SiO2 layer on one surface of the supporting substrate, then performing particle irradiation on the surface of the SiO2 layer to form a Si-rich oxide layer, and then sputtering deposition of Si element on the surface of the Si-rich oxide layer to form an amorphous Si layer; and performing a vacuum at an absolute pressure of ≤10 -3 In a vacuum environment of 1.37 Pa, the silicon lithium oxide layer containing the X element is bonded to the amorphous Si layer, the bonding pressure is 1000-100000N, and the bonding temperature is room temperature; The second method comprises: performing particle irradiation and Si element sputtering deposition on the ion implanted surface of the piezoelectric material substrate to form a silicon-lithium oxide layer containing the element X, and then sputtering and depositing Si element on the surface of the silicon-lithium oxide layer containing the element X to form an amorphous Si layer; preparing a SiO2 layer on one surface of the supporting substrate, and then performing particle irradiation on the surface of the SiO2 layer to form a Si-rich oxide layer; at an absolute pressure of ≤10 -3 In a vacuum environment of 1000 N / cm2, the amorphous Si layer is bonded to the Si-rich oxide layer at a bonding pressure of 1000-100000 N and a bonding temperature of room temperature; Wherein, the X element includes niobium and / or tantalum. In the first and second methods, the particles for particle irradiation are all neutral particles. The specific parameters include: The acceleration voltage of the particle beam is 0.1-10 kV, the current is 10-300 mA, and the irradiation time is 10-600 s; (3) The bonded body is heat treated at 100-300° C. for 10-120 min, so that the bonded body is broken along the weakened layer, thereby obtaining a composite piezoelectric substrate and a piezoelectric material substrate to be recycled.

10. An application of the composite piezoelectric substrate according to any one of claims 1 to 4, characterized in that: The composite piezoelectric substrate is used for manufacturing optoelectronic devices or acoustic wave equipment.

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