Preparation method of heterostructure and heterostructure

Abstract

The invention relates to the technical field of semiconductors, in particular to a preparation method of a heterostructure and the heterostructure. A first target substrate with a defect layer and a transition substrate are subjected to bonding, annealing and stripping treatment to obtain an intermediate heterostructure, the intermediate heterostructure comprises the transition substrate and a target film which are stacked, subsequently, the intermediate heterostructure is subjected to ion implantation, and the intermediate heterostructure and a second target substrate are subjected to bonding, annealing and stripping treatment to obtain the intermediate heterostructure. And removing the thin film layer of the transition substrate subjected to stripping treatment to obtain a target heterostructure comprising a second target substrate and a target thin film which are stacked. Therefore, the heterogeneous interface stress between the thin film of the first target substrate and the second target substrate can be effectively reduced, and direct heterogeneous integration of the thin film of the first target substrate and the second target substrate is further realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a preparation method of a heterostructure and the heterostructure. Background Art

[0002] The "universal ion knife" heterogeneous integration technology is a high-quality single crystal thin film technology with a wide range of applications, including acoustics, optics, and electrical devices. The universal ion knife heterogeneous integration technology breaks through many physical limitations and transfers functional films to substrates with practical application needs through ion implantation and bonding to achieve monolithic integration of multifunctional devices. However, due to the large difference in thermal expansion coefficients between the donor wafer and the bottom support wafer, the thermal stress of the interface during the annealing of the bonded wafer will exceed the interface bonding strength of the bonded wafer, making it easy for bonding to debond and wafer breakage to occur, which will make it difficult to integrate wafers with large mismatches in thermal expansion coefficients. Therefore, how to provide a method for preparing a heterostructure with adjustable thermal stress has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In order to solve the above technical problems, the present application discloses, on one hand, a method for preparing a heterostructure, which comprises the following steps:

[0004] Providing a first target substrate having a defective layer and a transition substrate; wherein the thermal expansion coefficient of the first target substrate is smaller than the thermal expansion coefficient of each of the transition substrates;

[0005] The first target substrate and the transition substrate are bonded, annealed and peeled to obtain an intermediate heterostructure; the intermediate heterostructure includes a stacked transition substrate and a target film; the target film is a film obtained by peeling the bonded first target substrate along the defective layer;

[0006] Performing ion implantation on the intermediate heterostructure with the surface of the target film as an implantation surface to form a defect layer in the transition substrate;

[0007] Providing a second target substrate; wherein the thermal expansion coefficient of the second target substrate is greater than the thermal expansion coefficient of the transition substrate;

[0008] The intermediate heterogeneous layer having the defective layer is bonded to the second target substrate, subjected to annealing and stripping treatment, and the thin film layer of the transition substrate after the stripping treatment is removed to obtain a target heterogeneous structure; the target heterogeneous structure includes the stacked second target substrate and the target thin film.

[0009] Optionally, the transition substrate includes a plurality of sub-transition substrates; the thermal expansion coefficients of the plurality of sub-transition substrates are different;

[0010] The step of bonding, annealing and peeling the first target substrate and the transition substrate to obtain an intermediate heterostructure includes:

[0011] The first target substrate and the target sub-transition substrate are bonded, annealed and peeled to obtain a first heterostructure; the first heterostructure includes a stacked target sub-transition substrate and the target film; the target sub-transition substrate is a sub-transition substrate with the smallest thermal expansion coefficient among the multiple sub-transition substrates;

[0012] Performing ion implantation on the first heterostructure with the surface of the target film as an implantation surface to form a defect layer in the target sub-transition substrate;

[0013] The first heterostructure having the defect layer is bonded to the remaining sub-transition substrate and subjected to annealing and peeling treatment to obtain the intermediate heterostructure; the remaining sub-transition substrate is a sub-transition substrate other than the target sub-transition substrate.

[0014] Optionally, in the case where the remaining sub-transition substrate includes at least two sub-transition substrates with different thermal expansion coefficients, the step of bonding the first heterostructure having the defect layer and the remaining sub-transition substrate and performing annealing and peeling treatment to obtain the intermediate heterostructure includes:

[0015] The first heterostructure having the defect layer is bonded to the target remaining sub-transition substrate, subjected to annealing and stripping treatment, and the thin film layer of the target sub-transition substrate after the stripping treatment is removed to obtain a second heterostructure; the target remaining sub-transition substrate is a remaining sub-transition substrate having the smallest thermal expansion coefficient among the remaining sub-transition substrates and not subjected to bonding treatment; the second heterostructure includes the stacked target remaining sub-transition substrate and the target thin film;

[0016] The second heterostructure is used as the first heterostructure, and ion implantation is performed on the first heterostructure with the surface of the target film as the implantation surface to form a defect layer in the target sub-transition substrate; the first heterostructure having the defect layer is bonded and annealed to the target remaining sub-transition substrate, and the thin film layer of the target sub-transition substrate after the peeling treatment is removed until there is no remaining sub-transition substrate that has not been bonded, thereby obtaining the intermediate heterostructure.

[0017] Optionally, a difference between a thermal expansion coefficient of the target remaining sub-transition substrate and a thermal expansion coefficient of the target sub-transition substrate is less than or equal to a preset threshold;

[0018] The preset threshold value is 0 to 1 ppm / K.

[0019] Optionally, the ions implanted include hydrogen ions, helium ions, or a combination of the two;

[0020] The energy range of the ion implantation includes 5keV to 1MeV;

[0021] The dose range of the ion implantation includes 1×10 12 cm -2 ~5×10 20 cm -2 .

[0022] Optionally, the bonding method includes hydrophilic direct bonding, surface activated bonding, metal melt bonding or anodic bonding;

[0023] The bonding conditions include:

[0024] The vacuum degree is 1×10 -3 Pa to 5×10 -7 Pa;

[0025] The pressure is 10MPa to 20MPa;

[0026] The temperature is between 25 and 500°C.

[0027] Optionally, the conditions of the annealing and stripping treatment include:

[0028] The atmosphere is at least one of vacuum, nitrogen, oxygen and inert gas;

[0029] Temperature is 100°C to 1000°C;

[0030] The time is from 1min to 240h.

[0031] Optionally, the target film has a thickness ranging from 50 nm to 1 μm.

[0032] Optionally, the transition substrate has a thickness ranging from 350 microns to 650 microns.

[0033] On the other hand, the present application also discloses a heterostructure, which is prepared by the above method.

[0034] In the embodiment of the present application, a first target substrate having a defect layer is bonded and annealed to a transition substrate to obtain an intermediate heterostructure, wherein the intermediate heterostructure includes a stacked transition substrate and a target film. Subsequently, ion implantation is performed on the intermediate heterogeneous substrate, and the intermediate heterogeneous substrate is bonded and annealed to a second target substrate to obtain a target heterogeneous structure including a stacked second target substrate and a target film. Since the thermal expansion coefficient of the transition substrate is between the first and second target substrates, the first target substrate is first bonded and peeled to the transition substrate, and then the obtained substrate is bonded and peeled to the second target substrate. In this way, the heterogeneous interface stress between the film of the first target substrate and the second target substrate can be effectively reduced, thereby achieving direct heterogeneous integration of the film of the first target substrate and the second target substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 This is a schematic diagram of an exemplary process for preparing a heterostructure in the present application;

[0037] Figure 2 to Figure 9 This is a schematic diagram of a structure in a process of preparing a heterostructure exemplified in the present application.

[0038] The following is a supplementary description of the attached drawings:

[0039] 1-first target substrate; 11-target thin film; 2-defective layer; 3-transition substrate; 31-target sub-transition substrate; 32-target remaining sub-transition substrate; 4-second target substrate. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0042] For the purpose of the following detailed description, it should be understood that the present invention may adopt various alternative changes and step sequences, unless expressly specified to the contrary. In addition, except in any operating examples, or otherwise indicated, all numbers representing the amount of ingredients used in the specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the attached claims are approximate values ​​that vary according to the desired performance to be obtained by the present invention. At least it is not intended to limit the application of the doctrine of equivalents to the scope of the claims, and each numerical parameter should at least be interpreted according to the number of reported significant figures and by applying ordinary rounding techniques.

[0043] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0044] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0045] See also Figure 1 , which is a schematic diagram of an exemplary process for preparing a heterostructure of the present application. The method for preparing a heterostructure may specifically include the following steps:

[0046] S101: providing a first target substrate having a defective layer and a transition substrate; the thermal expansion coefficient of the first target substrate is smaller than the thermal expansion coefficient of each of the transition substrates.

[0047] Exemplarily, the preparation process of the first target substrate 1 having the defect layer 2 may include: providing the first target substrate 1, performing ion implantation at a predetermined depth toward the first target substrate 1 to form the defect layer 2 in the first target substrate 1, and obtaining Figure 2 The structure shown.

[0048] Exemplarily, the ions implanted include hydrogen ions, helium ions, or a combination of the two; the energy range of the ion implantation includes 5keV to 1MeV; the dose range of the ion implantation includes 1×10 12 cm -2 ~5×10 20 cm -2 .

[0049] The materials of the first target substrate 1 and the transition substrate 3 are any one of silicon, silicon carbide, polycrystalline silicon carbide, silicon on insulator or silicon carbide, diamond, surface oxidized silicon wafer, sapphire, gallium nitride, germanium, gallium arsenide, indium phosphide, gallium oxide, zinc oxide, carbon, lithium niobate, lithium tantalate and quartz, etc., and are not limited here. Since the first target substrate 1 and the transition substrate 3 have different thermal expansion coefficients, the material type or lattice type of the two are different.

[0050] Exemplarily, the first target substrate 1 and the transition substrate 3 may both be wafer structures, that is, used for a large-plate molding process, or may be small-sized substrate structures for molding a single device, which is not limited here.

[0051] Exemplarily, the thickness of the first target substrate 1 and the transition substrate 3 may be the same or different, and there is no limitation here. Specifically, the thickness of the first target substrate 1 and the transition substrate 3 ranges from 350 microns to 650 microns, for example, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns or 650 microns.

[0052] In order to further reduce the strength of the bonding interface of the heterostructure finally prepared and avoid debonding and material fragmentation, the difference between the thermal expansion coefficients of the first target substrate 1 and the transition substrate 3 is less than or equal to a preset threshold, and the preset threshold can be 0 to 1 ppm / K, that is, the difference between the two is greater than 0 and less than or equal to 1 ppm / K.

[0053] It should be noted that the transition substrate 3 can be only one substrate, or it can include multiple sub-transition substrates; the thermal expansion coefficients of the multiple sub-transition substrates are different. The thickness of each sub-transition substrate can be 350 microns to 650 microns, the thermal expansion coefficient of the first target substrate 1 is different from the thermal expansion coefficient of each sub-transition substrate, and the thermal expansion coefficient of the first target substrate 1 is smaller than the thermal expansion coefficient of each sub-transition substrate. Take the transition substrate 3 as an example to illustrate that it includes three sub-transition substrates, and these three sub-transition substrates can be respectively called substrate A, substrate B and substrate C, then the thermal expansion coefficients of the first target substrate 1, substrate A, substrate B and substrate C can be sorted from small to large as the first target substrate 1, substrate A, substrate B and substrate C. The number of actual sub-transition substrates is not limited to the three in the above example, and can also be 1, 2, 4, etc. Optionally, the difference between the thermal expansion coefficients of sub-transition substrates with similar thermal expansion coefficients is greater than 0 and less than or equal to 1ppm / K.

[0054] S103: Bonding, annealing and peeling the first target substrate and the transition substrate to obtain an intermediate heterostructure; the intermediate heterostructure includes a stacked transition substrate and a target film; the target film is a film obtained by peeling the bonded first target substrate along the defective layer.

[0055] If the difference between the thermal expansion coefficients of the first target substrate 1 and the second target substrate 4 is within 2ppm / K, only one sub-transition substrate can be set. If the difference between the thermal expansion coefficients of the first target substrate 1 and the second target substrate 4 exceeds 2ppm / K, at least two sub-transition substrates need to be set.

[0056] Taking the example that the transition substrate 3 includes only one sub-transition substrate, step S103 can be specifically described as: bonding the first target substrate 1 and the sub-transition substrate, annealing and peeling, to obtain an intermediate heterostructure; the intermediate heterostructure includes a stacked transition substrate 3 and a target film 11; the target film 11 is a film obtained by peeling the bonded first target substrate 1 along the defective layer 2. Specifically, the injection surface of the first target substrate 1 can be bonded to the sub-transition substrate, then peeling is performed along the defective layer 2 of the first target substrate 1, and the peeled structure surface is polished to obtain the intermediate heterostructure.

[0057] Exemplarily, the bonding method includes hydrophilic direct bonding, surface activated bonding, metal melt bonding or anodic bonding.

[0058] Hydrophilic direct bonding refers to a bonding process in which a hydrophilic bonding reaction occurs at a hydrophilic interface. Plasma (such as Ar, N2, O2, etc.) is usually used to activate the bonding surface. After plasma activation, some organic matter and particles on the surface will be removed, and the density of hydrophilic dangling bonds on the surface will increase, thereby enhancing the hydrophilicity. Specifically, the surface of the retained layer 201 in the intermediate heterogeneous substrate and the surface of the supporting substrate 4 can be plasma activated, and a hydrophilic bonding reaction will subsequently occur on the plasma-activated surfaces of the two.

[0059] The specific process of surface activated bonding is to use plasma to treat the surface (different from the plasma surface activation in hydrophilic bonding). The entire surface plasma treatment and bonding process of the sample are carried out under high vacuum conditions. The substrate surface is first etched with plasma in a vacuum chamber to remove the oxide on the surface and increase the density of the surface dangling bonds, and then bonding is carried out in the vacuum chamber.

[0060] Metal bonding refers to bonding two wafers face to face by using pure metal or alloy, relying on metal bonds, diffusion between the metal and the wafer surface, metal melting, etc.

[0061] Anodic bonding applies a high voltage electric field to materials such as silicon and glass at high temperature, causing the sodium ions in the glass to migrate to the silicon surface, thereby forming a strong chemical bond. This technology has the advantages of high bonding strength and good airtightness, and is widely used in sensor packaging, microfluidic devices, etc.

[0062] The bonding conditions include: vacuum degree of 1×10 -3 Pa to 5×10 -7 Pa; pressure is 10MPa to 20MPa; temperature is between 25 and 500°C.

[0063] Exemplarily, the conditions of the annealing stripping treatment include: an atmosphere of at least one of vacuum, nitrogen, oxygen and inert gas; a temperature of 100° C. to 1000° C.; and a time of 1 min to 240 h.

[0064] Exemplarily, the target film 11 has a thickness ranging from 50 nm to 1 μm, for example, 50 nm, 150 nm, 300 nm, 450 nm, 550 nm, 650 nm, 750 nm, 850 nm, 950 nm or 1000 nm.

[0065] Taking the transition substrate 3 including a plurality of sub-transition substrates as an example, step S103 can be specifically described as follows:

[0066] S10311: Bonding, annealing and peeling the first target substrate 1 and the target sub-transition substrate 31 to obtain a first heterostructure; the first heterostructure includes a stacked target sub-transition substrate 31 and the target film 11; the target sub-transition substrate 31 is a sub-transition substrate with the smallest thermal expansion coefficient among the multiple sub-transition substrates.

[0067] By bonding the implantation surface of the first target substrate 1 to the target sub-transition substrate 31, the following can be obtained: Figure 3 The structure shown in FIG. 1 is then subjected to annealing and peeling treatment to obtain the structure shown in FIG. Figure 4 In the first heterostructure shown, since there may be a residual defect layer 2 on the surface of the target film 11 after annealing and stripping, the residual defect layer 2 can also be removed by a polishing process.

[0068] S10312 : performing ion implantation into the first heterostructure with the surface of the target film 11 as the implantation surface, so as to form a defect layer 2 in the target sub-transition substrate 31 .

[0069] The target sub-transition substrate 31 is several hundred microns thick, which is relatively thick. If the surface of the target sub-transition substrate 31 is used as the injection surface, the defect layer 2 cannot be accurately formed at the preset position. However, the target film 11 is only tens or hundreds of nanometers thick. If the surface of the target film 11 is used as the injection surface, the defect layer 2 can be accurately formed in the corresponding area of ​​the target sub-transition substrate, and then the following can be obtained: Figure 5 The structure shown.

[0070] S10313: Bonding, annealing and stripping the first heterostructure having the defect layer 2 and the remaining sub-transition substrate to obtain the intermediate heterostructure; the remaining sub-transition substrate is a sub-transition substrate other than the target sub-transition substrate 31.

[0071] Since the transition substrate 3 includes multiple sub-transition substrates, in order to avoid the problem of debonding or wafer breakage of the target film 11 during the bonding process, the sub-transition substrate selected for each bonding is the sub-transition substrate with the smallest difference in thermal expansion coefficient with the target film 11. Since the target film 11 will deform in the same way as the substrate wafer when heated, the thermal stress of the bonding interface mainly comes from the thermal mismatch difference between the upper and lower bulk materials. The above method can make the thermal expansion coefficients of the upper and lower sub-transition substrates of the target film 11 relatively close, which can buffer the thermal stress of the bonding interface, and thus realize reliable heterogeneous integration between materials with large thermal mismatch differences.

[0072] In another exemplary embodiment, when the remaining sub-transition substrates include sub-transition substrates with at least two thermal expansion coefficients, step S10313 can be specifically described as follows:

[0073] S10314: Bonding, annealing and stripping treatment are performed on the first heterostructure having the defect layer 2 and the target remaining sub-transition substrate 32, and the thin film layer of the target sub-transition substrate 31 after the stripping treatment is removed to obtain a second heterostructure; the target remaining sub-transition substrate 32 is the remaining sub-transition substrate with the smallest thermal expansion coefficient among the remaining sub-transition substrates and has not been bonded; the second heterostructure includes the stacked target remaining sub-transition substrate 32 and the target thin film 11.

[0074] By bonding the implantation surface of the first heterostructure with the defect layer 2 to the target remaining sub-transition substrate 32, the following can be obtained: Figure 6 The structure shown in FIG. 1 is subjected to annealing and peeling treatment to obtain the structure shown in FIG. Figure 7 The structure shown in FIG. 1 is then removed, and the thin film layer of the target transition substrate 31 after the stripping treatment is removed, that is, Figure 7 The thin film layer of the target sub-transition substrate 31 in the structure shown in the figure can be obtained as shown in FIG. Figure 8 The second heterostructure is shown.

[0075] Exemplarily, the thin film layer of the target sub-transition substrate 31 after the stripping process may be removed by chemical mechanical polishing, photolithography, or a combination of the two.

[0076] S10315: Use the second heterostructure as the first heterostructure, and perform ion implantation on the first heterostructure with the surface of the target film 11 as the implantation surface to form a defect layer 2 in the target sub-transition substrate 31; bond and anneal the first heterostructure with the defect layer 2 and the target remaining sub-transition substrate 32, and remove the thin film layer of the target sub-transition substrate 31 after the peeling process, until there is no remaining sub-transition substrate that has not been bonded, thereby obtaining the intermediate heterostructure.

[0077] The intermediate heterostructure can be obtained by using the second heterostructure as the first heterostructure and performing steps S13012 to S10314 until all sub-transition substrates are bonded.

[0078] Continuing with the above example in which the transition substrate 3 includes substrates A, B, and C, the target sub-transition substrate 31 is substrate A, and the target remaining sub-transition substrate 32 is the above-mentioned substrate B. First, the first target substrate 1 having a defective layer 2 is bonded and annealed to substrate A to obtain a first heterogeneous substrate, and then ion implantation is performed on the first heterogeneous substrate to form a defective layer 2 in substrate A of the first heterogeneous substrate. The first heterogeneous substrate having the defective layer 2 is bonded and annealed to substrate B to obtain a second heterogeneous substrate. Subsequently, ion implantation is performed on the second heterogeneous substrate, and the substrate C is bonded, annealed and peeled, and the thin film layer of substrate B is removed, and finally an intermediate heterogeneous structure of a target thin film 11 located on substrate C can be obtained. Since the thermal expansion coefficients of substrate A and substrate B are close, and the thermal expansion coefficients of substrate B and substrate C are close, the problem of thin film fragmentation caused by lattice thermal mismatch during the bonding process of the target thin film 11 can be avoided.

[0079] Since in each bonding, the sub-transition substrates located above and below the target film 11 layer are the two sub-transition substrates with the closest thermal expansion coefficients among the multiple sub-transition substrates, the interface thermal stress can be gradually alleviated, and the heterogeneous integration of two materials with large differences in thermal expansion coefficients can be achieved, meeting the material requirements of functional devices.

[0080] Exemplarily, the difference between the thermal expansion coefficient of the target remaining sub-transition substrate 32 and the thermal expansion coefficient of the target sub-transition substrate 31 is less than or equal to a preset threshold; the preset threshold is 0 to 1 ppm / K.

[0081] In the above steps S10311-S10315, the ions implanted include hydrogen ions, helium ions, or a combination of the two; the energy range of the ion implantation includes 5keV to 1MeV; the dose range of the ion implantation includes 1×10 12 cm -2 ~5×10 20 cm -2 The bonding conditions include: vacuum degree of 1×10 -3 Pa to 5×10 -7 Pa; pressure is 10MPa to 20MPa; temperature is between 25 and 500°C. The conditions of the annealing and stripping treatment include: atmosphere is at least one of vacuum, nitrogen, oxygen and inert gas; temperature is 100°C to 1000°C; time is 1min to 240h.

[0082] S105: performing ion implantation into the intermediate heterostructure with the surface of the target film as an implantation surface to form a defect layer in the transition substrate.

[0083] Exemplarily, the ions implanted include hydrogen ions, helium ions, or a combination of the two; the energy range of the ion implantation includes 5keV to 1MeV; the dose range of the ion implantation includes 1×10 12 cm -2 ~5×10 20 cm -2 .

[0084] S107: providing a second target substrate; the thermal expansion coefficient of the second target substrate is greater than the thermal expansion coefficient of the transition substrate.

[0085] Continuing with the above example, the order of thermal expansion coefficients of the first and second target substrates 4 , and substrates A, B, and C is: first target substrate 1 < substrate A < substrate B < substrate C < second target substrate 4 .

[0086] S109: Bonding the intermediate heterogeneous layer with the defective layer and the second target substrate, performing annealing and stripping treatment, and removing the thin film layer of the transition substrate after the stripping treatment to obtain a target heterogeneous structure, that is, Fig. 9 The structure shown; the target heterostructure includes the stacked second target substrate and the target thin film.

[0087] Exemplarily, the bonding conditions include: a vacuum degree of 1×10 -3 Pa to 5×10 -7 Pa; pressure is 10MPa to 20MPa; temperature is between 25 and 500°C. The conditions of the annealing and stripping treatment include: atmosphere is at least one of vacuum, nitrogen, oxygen and inert gas; temperature is 100°C to 1000°C; time is 1min to 240h.

[0088] Exemplarily, the material of the second target substrate 4 is any one of silicon, silicon carbide, polycrystalline silicon carbide, silicon on insulator or silicon carbide, diamond, surface oxidized silicon wafer, sapphire, gallium nitride, germanium, gallium arsenide, indium phosphide, gallium oxide, zinc oxide, carbon, lithium niobate, lithium tantalate and quartz, etc., without limitation herein.

[0089] It should be noted that each time ions are implanted into the target substrate (such as the first and second target substrates 4 and the sub-transition substrate), the target substrate can be divided into two films of different thicknesses, wherein the thickness of the film close to the target film 11 can be approximately the same as the thickness of the target film 11 .

[0090] The method for preparing a heterogeneous structure provided in the present application can be for heterogeneous integration of two materials with certain differences in thermal expansion coefficients. For example, if the final structure required is an integrated structure of material A and material B, the difference in thermal expansion coefficients between material A and material B can be determined first, and the number and type of transition materials can be selected according to the difference between the two. Assuming that N transition materials are included, the thermal expansion coefficients of these N transition materials and material A and material B meet the following conditions: CTE A <CTE1<CTE2……<CTE N <CTE B .

[0091] Subsequently, transition material 1 (i.e., the transition material with the smallest thermal expansion coefficient among the N transition materials) is screened out from the N transition materials, and the ion-implanted material A is bonded, annealed, and peeled off with the transition material 1 to obtain the target film 11 (material A) located on the transition material 1.

[0092] Next, transition material 2 (the transition material with the smallest thermal expansion coefficient among the remaining N-1 transition materials) is screened out, and ion implantation is performed on transition material 1 with the surface of target film 11 as the injection surface. It is then bonded to transition material 2, annealed and peeled off to form a structure of transition material 2-target film 11-transition material 1. Then, transition material 1 is removed to obtain a structure of transition material 2-target film 11.

[0093] The processing process for the subsequent N-2 transition materials and material B is the same as the above-mentioned processing process for transition material 2. When the bonding, annealing and peeling of all transition materials and material B are completed, the structure of material B-target film 11 can be obtained, that is, the integration of the target heterostructure.

[0094] Since in each bonding, the sub-transition substrates located above and below the target film 11 layer are the two sub-transition substrates with the closest thermal expansion coefficients among the multiple sub-transition substrates, the interface thermal stress can be gradually alleviated, and the heterogeneous integration of two materials with large differences in thermal expansion coefficients can be achieved, meeting the material requirements of functional devices.

[0095] On the other hand, the present application also discloses a heterostructure, which is prepared by the above method.

[0096] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a heterostructure, characterized in that: The following steps are involved: Providing a first target substrate having a defective layer and a transition substrate; wherein the thermal expansion coefficient of the first target substrate is smaller than the thermal expansion coefficient of each of the transition substrates; The first target substrate and the transition substrate are bonded, annealed and peeled to obtain an intermediate heterostructure; the intermediate heterostructure includes the stacked transition substrate and the target film; the target film is a film obtained by peeling the bonded first target substrate along the defective layer; Performing ion implantation on the intermediate heterostructure with the surface of the target film as an implantation surface to form a defect layer in the transition substrate; Providing a second target substrate; wherein the thermal expansion coefficient of the second target substrate is greater than the thermal expansion coefficient of the transition substrate; The intermediate heterogeneous layer having the defective layer is bonded to the second target substrate, subjected to annealing and stripping treatment, and the thin film layer of the transition substrate after the stripping treatment is removed to obtain a target heterogeneous structure; the target heterogeneous structure includes the stacked second target substrate and the target thin film.

2. The preparation method according to claim 1, characterized in that: The transition substrate comprises a plurality of sub-transition substrates; the thermal expansion coefficients of the plurality of sub-transition substrates are different; The step of bonding, annealing and peeling the first target substrate and the transition substrate to obtain an intermediate heterostructure includes: The first target substrate and the target sub-transition substrate are bonded, annealed and peeled to obtain a first heterostructure; the first heterostructure includes a stacked target sub-transition substrate and the target film; the target sub-transition substrate is a sub-transition substrate with the smallest thermal expansion coefficient among the multiple sub-transition substrates; Performing ion implantation on the first heterostructure with the surface of the target film as an implantation surface to form a defect layer in the target sub-transition substrate; The first heterostructure having the defect layer is bonded to the remaining sub-transition substrate and subjected to annealing and peeling treatment to obtain the intermediate heterostructure; the remaining sub-transition substrate is a sub-transition substrate other than the target sub-transition substrate.

3. The preparation method according to claim 2, characterized in that: In the case where the remaining sub-transition substrate includes at least two sub-transition substrates with thermal expansion coefficients, bonding the first heterostructure having the defect layer and the remaining sub-transition substrate, and performing annealing and peeling treatment to obtain the intermediate heterostructure, comprises: The first heterostructure having the defect layer is bonded to the target remaining sub-transition substrate, subjected to annealing and stripping treatment, and the thin film layer of the target sub-transition substrate after the stripping treatment is removed to obtain a second heterostructure; the target remaining sub-transition substrate is a remaining sub-transition substrate having the smallest thermal expansion coefficient among the remaining sub-transition substrates and not subjected to bonding treatment; the second heterostructure includes the stacked target remaining sub-transition substrate and the target thin film; The second heterostructure is used as the first heterostructure, and ion implantation is performed on the first heterostructure with the surface of the target film as the implantation surface to form a defect layer in the target sub-transition substrate; the first heterostructure having the defect layer is bonded and annealed to the target remaining sub-transition substrate, and the thin film layer of the target sub-transition substrate after the peeling treatment is removed until there is no remaining sub-transition substrate that has not been bonded, thereby obtaining the intermediate heterostructure.

4. The preparation method according to claim 3, characterized in that: The difference between the thermal expansion coefficient of the target remaining sub-transition substrate and the thermal expansion coefficient of the target sub-transition substrate is less than or equal to a preset threshold; The preset threshold value is 0 to 1 ppm / K.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The ions implanted include hydrogen ions, helium ions or a combination of the two; The energy range of the ion implantation includes 5keV to 1MeV; The dose range of the ion implantation includes 1×10 12 cm -2 ~5×10 20 cm -2 .

6. The preparation method according to any one of claims 1 to 4, characterized in that: The bonding method includes hydrophilic direct bonding, surface activated bonding, metal melting bonding or anodic bonding; The bonding conditions include: The vacuum degree is 1×10 -3 Pa to 5×10 -7 Pa; The pressure is 10MPa to 20MPa; The temperature is between 25 and 500°C.

7. The preparation method according to any one of claims 1 to 4, characterized in that: The conditions of the annealing and stripping treatment include: The atmosphere is at least one of vacuum, nitrogen, oxygen and inert gas; Temperature is 100°C to 1000°C; The time is from 1min to 240h.

8. The preparation method according to any one of claims 1 to 4, characterized in that: The target film has a thickness ranging from 50 nm to 1 μm.

9. The preparation method according to any one of claims 1 to 4, characterized in that: The transition substrate has a thickness ranging from 350 microns to 650 microns.

10. A heterostructure, characterized in that The method is prepared by any one of claims 1 to 8.

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