Semiconductor film and preparation method thereof
By patterning the hollow structure on the substrate and removing the substrate by wet etching, the stress problem caused by mismatch between the semiconductor film and the heterogeneous substrate is solved, and the preparation of high-quality semiconductor film is achieved.
Patent Information
- Application Number
- CN202311338765.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-16
- Publication Date
- 2025-04-18
AI Technical Summary
In the prior art, there is a large-scale lattice mismatch and thermal mismatch between semiconductor films and heterogeneous substrates, resulting in increased stress and making it difficult to prepare high-quality self-supported semiconductor films.
By patterning the substrate, a semiconductor film with a hollow structure is formed, and the substrate is further removed by wet etching to form a second groove, so that the semiconductor film is suspended and the stress is reduced.
The stress between the semiconductor film and the substrate is effectively reduced, the dislocation density is reduced, and cracks are avoided, and the high-quality semiconductor film with no cracks, low dislocation density and good crystal surface state is finally obtained.
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Figure CN119852175A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology and in particular to a semiconductor film and a method for preparing the same. Background Art
[0002] Semiconductor films prepared based on heteroepitaxial technologies such as Metal-Organic Chemical Vapor Deposition (MOCVD) have large lattice mismatch and thermal mismatch between the heterogeneous substrate (such as sapphire, silicon, etc.) used in heteroepitaxial and the semiconductor film material, which leads to stress between the semiconductor film and the heterogeneous substrate. As a result, cracks will appear when the semiconductor film is prepared to a certain thickness, which seriously affects the quality of the semiconductor film.
[0003] AlN self-supporting substrates are very expensive. Currently, most AlN single crystal films are obtained on sapphire, silicon, SiC and other substrates through metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE) and other methods. Growing AlN films on silicon substrates is a huge challenge. On the one hand, due to the large lattice mismatch between silicon substrates and AlN materials, a large number of threading dislocations are generated during the production process. These threading dislocations lead to poor material quality and limit the performance of various devices. In addition, the lattice mismatch also causes AlN to generate huge tensile stress during the growth process, which eventually causes cracks in the epitaxial film and makes it unusable. On the other hand, due to the large thermal mismatch between AlN and silicon substrate materials, that is, the difference in thermal expansion coefficients, the AlN epitaxial film grown at high temperature will generate additional tensile stress during the cooling process, causing the epitaxial film to crack and become unusable. In short, the high dislocation density and the crack problem caused by tensile stress greatly limit the device application of heteroepitaxial AlN thin film materials. Summary of the invention
[0004] The main purpose of the present disclosure is to provide a semiconductor film and a method for preparing the same, so as to solve the problem in the prior art that the semiconductor film has a large mismatch with the heterogeneous substrate, the stress is large, and it is difficult to prepare a high-quality self-supporting semiconductor film.
[0005] According to one aspect of the present disclosure, a method for preparing a semiconductor thin film provided by an embodiment of the present disclosure includes the following steps:
[0006] providing a substrate;
[0007] patterning the substrate, wherein the patterned substrate has first grooves separated from each other and growth regions surrounding the first grooves;
[0008] Preparing a semiconductor film on the growth region, wherein the semiconductor film forms a hollow structure at a position corresponding to the first groove;
[0009] Using the semiconductor film as a mask and through the hollow structure, the first groove is etched to form a second groove by wet etching, wherein the orthographic projection area of the second groove on the plane where the substrate is located is larger than the orthographic projection area of the hollow structure on the plane where the substrate is located.
[0010] As an optional embodiment, multiple first grooves are connected together after being etched to form the second groove, and the semiconductor film with a hollow structure is suspended on the second groove. The hollow structure includes multiple through holes, and the multiple through holes are connected to the second groove.
[0011] As an optional embodiment, the multiple through holes of the hollow structure have the same size and are evenly distributed.
[0012] As an optional embodiment, the substrate includes multiple substrate sub-regions, the first grooves in each of the substrate sub-regions have the same size and are evenly distributed; the first grooves of at least two of the substrate sub-regions have different sizes; and the hole area density of the hollow structure corresponding to at least two of the substrate sub-regions is different.
[0013] As an optional embodiment, the substrate includes a plurality of second grooves, and at least two of the second grooves have different sizes.
[0014] As an optional embodiment, the semiconductor film includes a first semiconductor film and a second semiconductor film formed on the first semiconductor film, and the step of preparing the semiconductor film on the growth region is:
[0015] Prepare a first semiconductor film in the growth region, wherein the first semiconductor film forms a hollow structure at a position corresponding to the first groove;
[0016] Using the first semiconductor film as a mask, the first groove is etched to form a second groove through the hollow structure by wet etching;
[0017] The second semiconductor film is continuously grown on the first semiconductor film with the hollow structure, and the hollow structure extending from the first semiconductor film partially penetrates or completely penetrates the second semiconductor film.
[0018] As an optional embodiment, the material of the semiconductor film is one of AlN, GaN and AlScN.
[0019] As an optional embodiment, the second semiconductor film and the first semiconductor film are made of different materials.
[0020] As an optional embodiment, the material of the first semiconductor film is AlN, the material of the second semiconductor film is AlScN, and the doping method of the Sc component in the second semiconductor film includes uniform doping, modulation doping or periodic doping.
[0021] As an optional embodiment, the substrate is a SOI silicon-on-insulator substrate, the SOI silicon-on-insulator substrate includes a stacked support layer, a bonding layer and the active silicon layer, and the first groove is arranged in the active silicon layer.
[0022] As an optional embodiment, the substrate is a QST engineered substrate, and the QST engineered substrate includes a stacked polycrystalline ceramic core, a barrier layer, a bonding layer, and the active silicon layer, and the first groove is arranged in the active silicon layer.
[0023] According to another aspect of the present disclosure, the present disclosure also provides a semiconductor thin film, which is obtained by any of the preparation methods described above.
[0024] According to another aspect of the present disclosure, the semiconductor film provided by the present disclosure is used in the fields of acoustic wave resonators, light emitting diodes, high electron mobility transistors, high mobility diodes, MOSFETs, UV-LEDs, photodetectors, hydrogen generators or solar cells.
[0025] The present disclosure provides a semiconductor film and a preparation method thereof, which utilizes a patterned substrate to form a semiconductor film with a hollow structure, uses the semiconductor film as a mask, and further removes the substrate through the hollow structure by wet etching, and a first groove is etched to form a second groove, and the orthographic projection area of the second groove on the plane where the substrate is located is larger than the orthographic projection area of the hollow structure on the plane where the substrate is located. During the growth process, because the first groove is further etched, part of the semiconductor film is suspended above the second groove, and the suspended structure can relax and reduce the stress caused by lattice mismatch and thermal mismatch between the semiconductor film and the substrate, thereby inhibiting the generation of cracks; on the other hand, because the substrate is further removed, the contact interface between the substrate and the semiconductor film is reduced, and the number of dislocations formed at the interface between the substrate and the semiconductor film will also be further reduced. During the growth process of the semiconductor film, the dislocations will be further annihilated, and finally a high-quality semiconductor film with no cracks, low dislocation density, and good crystal surface state is obtained. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1a to Figure 1d FIG. 1 is a schematic diagram of a process flow of a method for preparing a semiconductor thin film according to Embodiment 1 of the present disclosure;
[0027] Figure 2 It is a schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the second embodiment of the present disclosure;
[0028] Figures 3a to 3d The above is a schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the third embodiment of the present disclosure;
[0029] Figure 4 It is a schematic top view of the substrate sub-region in the third embodiment of the present disclosure;
[0030] Figure 5 FIG. 1 is a schematic diagram of a process flow of a method for preparing a semiconductor thin film according to a fourth embodiment of the present disclosure;
[0031] Figures 6a to 6c Schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the fifth embodiment of the present disclosure. DETAILED DESCRIPTION
[0032] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.
[0033] In order to solve the problem in the prior art that the semiconductor film has a large mismatch with the heterogeneous substrate, the stress is large, and it is difficult to prepare a high-quality self-supporting semiconductor film, the present disclosure provides a semiconductor film and a preparation method thereof, a semiconductor film with a hollow structure is formed by using a patterned substrate, the semiconductor film is used as a mask, and the substrate is further removed by wet etching, a first groove is etched to form a second groove, the orthographic projection area of the second groove on the plane where the substrate is located is larger than the orthographic projection area of the hollow structure on the plane where the substrate is located, during the growth process, because the first groove is further etched, part of the semiconductor film is suspended on the second groove, and the suspended structure can relax the tensile stress and inhibit the generation of cracks; on the other hand, because the substrate is further removed, the contact interface between the substrate and the semiconductor film is reduced, the number of dislocations formed at the interface between the substrate and the semiconductor film will be further reduced, and the dislocations will be further annihilated during the growth of the semiconductor film, and finally a high-quality semiconductor film with no cracks and low dislocation density is obtained.
[0034] The semiconductor thin film and the method for preparing the same mentioned in the present disclosure are further illustrated below with reference to FIGS. 1 to 6 .
[0035] Embodiment 1
[0036] Figure 1a to Figure 1d Shown is a schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the first embodiment of the present disclosure.
[0037] Step S1: Figure 1a As shown, a substrate is provided;
[0038] Step S2: Figure 1b As shown, the substrate 10 is patterned, and the patterned substrate 10 has first grooves 11 separated from each other and a growth area 12 surrounding the first grooves 11;
[0039] Step S3: Figure 1c As shown, a semiconductor film 20 is prepared on the growth region 12, and a hollow structure 30 is formed in the semiconductor film 20 at a position corresponding to the first groove 11;
[0040] Step S4: Figure 1d In the above method, the semiconductor film 20 is used as a mask, and the substrate 10 is further removed by wet etching through the hollow junction 30. The first groove 11 is further etched to form a second groove 13, wherein the orthographic projection area of the second groove 13 on the plane where the substrate 10 is located is larger than the orthographic projection area of the hollow structure 21 on the plane where the substrate is located, that is, the semiconductor film 20 is partially suspended on the second groove, and the suspended semiconductor film 20 can further release the lattice mismatch stress.
[0041] In this embodiment, the material of the semiconductor film 20 is a hexagonal semiconductor material, for example, it can be one of AlN, GaN, InN, AlScN, AlGaN, AlInGaN or an alloy combination; the growth of the semiconductor film 20 can be in-situ growth, or it can be obtained by atomic layer deposition (ALD, Atomic layer deposition), or chemical vapor deposition (CVD, Chemical Vapor Deposition), or molecular beam epitaxy (MBE, Molecular Beam Epitaxy), or plasma enhanced chemical vapor deposition (PECVD, Plasma Enhanced Chemical Vapor Deposition), or low pressure chemical vapor deposition (LPCVD, Low Pressure Chemical Vapor Deposition), or metal organic chemical vapor deposition (MOCVD, Metal-Organic Chemical Vapor Deposition), or a combination thereof. Unless otherwise specified, the growth conditions of the semiconductor film 20 can be used by those skilled in the art or adjusted according to specific needs.
[0042] In this embodiment, the material of the substrate 1 is one of sapphire, silicon or silicon carbide.
[0043] In this embodiment, the substrate is a composite substrate, the composite substrate is an SOI silicon-on-insulator substrate, the SOI silicon-on-insulator substrate includes a stacked support layer, a bonding layer and the active silicon layer, and the first groove is arranged in the active silicon layer;
[0044] The composite substrate is a QST engineered substrate, which includes a stacked polycrystalline ceramic core, a barrier layer, a bonding layer, and the active silicon layer, wherein the first groove is arranged in the active silicon layer.
[0045] In this embodiment, the horizontal cross-sectional shape of the first groove 11 is any one of a triangle, a circle, an ellipse, a polygon, a strip, a mesh, etc., and the cross-sectional shape is parallel to the substrate 10 .
[0046] The “area density” herein refers to the proportion of the total projected area of the holes (including the first grooves, the second grooves, and the hollow structure) in the unit area of the substrate or the semiconductor film in the top view direction.
[0047] In this embodiment, the area density of the first grooves on the substrate is uniform; because the hollow structure on the semiconductor film corresponds to the first grooves, the distribution of the first grooves determines the distribution of the hollow structure of the semiconductor film. When the area density of the first grooves on the substrate is uniform, the area density of the corresponding hollow structures on the semiconductor film is uniform. Optionally, the area density of the first grooves on the substrate is symmetrical and periodically changes. The distribution of the first grooves on the substrate serves to release stress and adjust the uneven stress distribution caused by lattice mismatch and thermal mismatch between the semiconductor film and the substrate. In some embodiments, the area density of the first grooves on the substrate can be adjusted according to actual needs, without limitation.
[0048] Embodiment 2
[0049] Figure 2 The process flow diagram of the method for preparing a semiconductor thin film according to the second embodiment of the present disclosure is shown. The method for preparing a semiconductor thin film according to the second embodiment is substantially the same as the method for preparing a semiconductor thin film according to the first embodiment, specifically, steps S1 to S3 are the same, see Figure 1a to Figure 1c , the difference is:
[0050] Step S4: Figure 2As shown, with the first semiconductor film 20 as a mask, the substrate 10 is further removed by wet etching through the hollow structure 30, the first groove 11 is etched to form a second groove 13, and multiple first grooves 11 are connected together after being etched to form a second groove, and the semiconductor film 20 with a hollow structure is suspended on the second groove, and the hollow structure 30 includes multiple through holes, and multiple through holes are connected to the second groove. In the second embodiment, multiple first grooves 11 are connected together after being etched to form a second groove 13, and the semiconductor film with a hollow structure is suspended on the second groove. In this embodiment, the size of the second groove is further enlarged, the substrate is further removed, the area of the semiconductor film 20 suspended on the second groove is increased, the contact interface between the substrate and the semiconductor film is reduced, and the number of dislocations formed at the interface between the substrate and the semiconductor film will also be further reduced. Dislocations will be further annihilated during the growth process of the semiconductor film, and finally a high-quality semiconductor film with no cracks, low dislocation density, and good crystal surface state is obtained.
[0051] Embodiment 3
[0052] Figures 3a to 3d The above is a schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the third embodiment of the present disclosure.
[0053] The method for preparing the semiconductor film of the third embodiment is substantially the same as the method for preparing the semiconductor film of the first to second embodiments, with the only difference being that the substrate comprises a plurality of substrate sub-regions, the area density of the first grooves of at least two of the substrate sub-regions is different, and the area density of the hollow structures corresponding to at least two of the substrate sub-regions is different.
[0054] The preparation method of embodiment three is as follows:
[0055] Step S1: Figure 3a As shown, the substrate 10 includes a first substrate sub-region A1 and a second substrate sub-region A2;
[0056] Step S2: Figure 3b As shown, the above-mentioned substrate 10 is patterned, and the area density of the first grooves 111 in the first substrate sub-area A1 is less than the area density of the first grooves 111 in the second substrate sub-area A2. Optionally, the first grooves 111 in the first substrate sub-area A1 have the same size, are evenly distributed, and have a first size d1; the first grooves 112 in the second substrate sub-area A2 have the same size, are evenly distributed, and have a second size d2; the first size d1 is smaller than the second size.
[0057] Step S3: Figure 3c As shown, a semiconductor film 20 is prepared on the growth region 12, and a hollow structure 30 is formed in the semiconductor film 20 at a position corresponding to the first groove 11;
[0058] Step S4: Figure 3d In the above method, the semiconductor film 20 is used as a mask, and the substrate 10 is further removed by wet etching through the hollow junction 30. The first groove 11 is further etched to form a second groove 13, wherein the orthographic projection area of the second groove 13 on the plane where the substrate 10 is located is larger than the orthographic projection area of the hollow structure 21 on the plane where the substrate is located, that is, the semiconductor film 20 is partially suspended on the second groove, and the suspended semiconductor film 20 can further release the lattice mismatch stress; Figure 3d It can be seen that the area density of the hollow structure 31 corresponding to the first substrate sub-area A1 is smaller than the area density of the hollow structure 32 corresponding to the second substrate sub-area A2. The stress distribution at the interface can be further adjusted by adjusting the area density of the hollow structures corresponding to different sub-areas.
[0059] The first grooves are distributed on the substrate to release stress and adjust the uneven stress distribution between the semiconductor film and the substrate due to lattice mismatch and thermal mismatch. In this embodiment, the stress at the interface between the substrate and the semiconductor film is regulated simply and efficiently by dividing the substrate into substrate sub-areas. In some embodiments, the area density of the first grooves on the substrate can be adjusted according to actual needs, but is not limited to this. It should be noted that the partitions of the substrate 10 are not limited to two, and the number of substrate sub-areas can be set according to actual needs.
[0060] Figure 4 1 is a schematic top view of the substrate sub-region in the third embodiment of the present disclosure. In this embodiment, the first substrate sub-region A1 is the central region of the substrate 10, and the second substrate sub-region A2 is the edge region of the substrate 10. During the growth of the semiconductor thin film 20, the edge region and the substrate region are unevenly distributed, and the area density of the first grooves in the edge region and the central region can be adjusted according to actual needs. Optionally, the area density of the first grooves in the edge region is greater than the area density of the first grooves in the central region.
[0061] Embodiment 4
[0062] Figure 5 The process flow diagram of the method for preparing a semiconductor thin film according to the fourth embodiment of the present disclosure is shown. The method for preparing a semiconductor thin film according to the fourth embodiment is substantially the same as the method for preparing a semiconductor thin film according to the first to third embodiments, except that:
[0063] Step S4: Figure 5As shown, the substrate 10 is further removed by wet etching through the hollow structure 30 using the first semiconductor film 20 as a mask, and the first groove 11 is etched to form a second groove 13. The substrate 10 includes a plurality of second grooves 13, and at least two second grooves 13 have different sizes. In this embodiment, the size of the second groove 13 is regulated by regulating the wet etching. In this embodiment, the second groove 13 can be formed by etching a single first groove, or can be formed by etching a plurality of first grooves connected together, but is not limited thereto.
[0064] Embodiment 5
[0065] Figures 6a to 6c Schematic diagram of the process flow of the method for preparing a semiconductor thin film according to the fifth embodiment of the present disclosure.
[0066] The method for preparing the semiconductor film of the fifth embodiment is substantially the same as the method for preparing the semiconductor film of the first to fourth embodiments, with the only difference being that the semiconductor film includes a first semiconductor film and a second semiconductor film formed on the first semiconductor film, and the hollow structure portion extending from the first semiconductor film penetrates the second semiconductor film.
[0067] In the fifth embodiment, the semiconductor film is prepared on the growth region 12 as follows:
[0068] like Figure 6a As shown, a first semiconductor film 21 is prepared in the growth region 12, and a hollow structure 30 is formed in the first semiconductor film 21 at a position corresponding to the first groove 11; the first semiconductor film 21 is used as a mask, and the substrate 10 is further removed through the hollow structure by wet etching, and the first groove 11 is further etched to form a second groove 13;
[0069] like Figure 6b As shown, a second semiconductor film 22 is continuously grown on the first semiconductor film 21 having a hollow structure, and the hollow structure portion extending from the first semiconductor film penetrates the second semiconductor film; Figure 6c As shown, the hollow structure 30 extending from the first semiconductor film 21 completely penetrates the second semiconductor film 22 .
[0070] In this embodiment, the second semiconductor film is made of different materials from the first semiconductor film. Optionally, the material of the first semiconductor film is AlN, the material of the second semiconductor film is AlScN, and the doping method of the Sc component of the second semiconductor film includes uniform doping, modulation doping or periodic doping.
[0071] In this embodiment, the hollow structure disclosed in the present invention can reduce the stress caused by lattice mismatch and thermal mismatch between the semiconductor film and the heterogeneous substrate. After etching to form the second groove, the first semiconductor film is suspended on the second groove. Since the contact area between the substrate and the first semiconductor film is greatly reduced, the stress at the interface is greatly relieved; the second semiconductor film continues to grow above the suspended first semiconductor film, and defects can be merged during the process of growing the second semiconductor film, further reducing the defect density, thereby obtaining a second semiconductor film with low defect density on the upper surface and good crystal state, which is conducive to further preparing high-quality nitride substrate materials and nitride semiconductor devices with a certain thickness on the second semiconductor film.
[0072] The present disclosure also provides a semiconductor thin film, which is obtained according to the semiconductor thin film preparation method provided in Examples 1 to 5. The semiconductor thin film is used in the fields of acoustic wave resonators, light emitting diodes, high electron mobility transistors, high mobility diodes, MOSFETs, UV-LEDs, photodetectors, hydrogen generators or solar cells.
[0073] The present invention provides a semiconductor film and a preparation method thereof, wherein a semiconductor film with a hollow structure is formed by using a patterned substrate, the semiconductor film is used as a mask, and the substrate is further removed by wet etching, the first groove is etched to form a second groove, the orthographic projection area of the second groove on the plane where the substrate is located is larger than the orthographic projection area of the hollow structure on the plane where the substrate is located, during the growth process, because the first groove is further etched, part of the semiconductor film is suspended on the second groove, and the suspended structure can relax the tensile stress and inhibit the generation of cracks; on the other hand, because the substrate is further removed, the contact interface between the substrate and the semiconductor film is reduced, and the number of dislocations formed at the interface between the substrate and the semiconductor film will also be further reduced, and the dislocations will be further annihilated during the growth process of the semiconductor film, and finally a high-quality semiconductor film with no cracks and low dislocation density is obtained. Not only can the dislocation defect density and stress be effectively reduced, but also the preparation process is simple, the cost is low, and the merging effect is good, the defect density is low, and the material crystal quality is good, which is particularly suitable for large-scale industrial production.
[0074] The present disclosure provides a method for preparing a semiconductor thin film, which can obtain a thick film material with a high growth rate and a low dislocation density, has low production cost, flexible growth conditions and good reproducibility. In the process of peeling the semiconductor thin film from the substrate, no complex and expensive laser peeling equipment is required, only cheap chemical etching liquid is required, so the cost is low.
[0075] It should be understood that the term "including" and its variations used in the present disclosure are open inclusions, that is, "including but not limited to". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment". In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.
[0076] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.
Claims
1. A method for preparing a semiconductor thin film, characterized in that: The following steps are involved: providing a substrate; patterning the substrate, wherein the patterned substrate has first grooves separated from each other and growth regions surrounding the first grooves; Preparing a semiconductor film on the growth region, wherein the semiconductor film forms a hollow structure at a position corresponding to the first groove; Using the semiconductor film as a mask and through the hollow structure, the first groove is etched to form a second groove by wet etching, wherein the orthographic projection area of the second groove on the plane where the substrate is located is larger than the orthographic projection area of the hollow structure on the plane where the substrate is located.
2. The method for preparing a semiconductor thin film according to claim 1, characterized in that: After being etched, a plurality of the first grooves are connected together to form the second groove, and the semiconductor film with the hollow structure is suspended on the second groove. The hollow structure includes a plurality of through holes, and the plurality of through holes are connected to the second groove.
3. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The area density of the first grooves on the substrate is uniform; the area density of the hollow structures on the semiconductor film is uniform.
4. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The substrate comprises a plurality of substrate sub-regions, at least two of the substrate sub-regions have different area densities of the first grooves, and at least two of the substrate sub-regions have different area densities of the hollow structures corresponding to them.
5. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The substrate comprises an edge region and a central region, and an area density of the first grooves in the edge region is greater than a corresponding area density in the central region.
6. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The substrate includes a plurality of second grooves, and at least two of the second grooves have different sizes.
7. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The semiconductor film includes a first semiconductor film and a second semiconductor film formed on the first semiconductor film, and the semiconductor film is prepared on the growth region as follows: Prepare a first semiconductor film in the growth region, wherein the first semiconductor film forms a hollow structure at a position corresponding to the first groove; Using the first semiconductor film as a mask, through the hollow structure, by wet etching, a first groove is further etched to form a second groove; The second semiconductor film is continuously grown on the first semiconductor film with the hollow structure, and the hollow structure extending from the first semiconductor film partially penetrates or completely penetrates the second semiconductor film.
8. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The material of the semiconductor film is one of AlN, GaN and AlScN.
9. The method for preparing a semiconductor thin film according to claim 7, characterized in that: The second semiconductor film is made of a different material from the first semiconductor film.
10. The method for preparing a semiconductor thin film according to claim 7, characterized in that: The material of the first semiconductor film is AlN, the material of the second semiconductor film is AlScN, and the doping method of the Sc component in the second semiconductor film includes uniform doping, modulation doping or periodic doping.
11. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The substrate is a SOI silicon-on-insulator substrate, which includes a support layer, a bonding layer and the active silicon layer which are stacked, and the first groove is arranged in the active silicon layer.
12. The method for preparing a semiconductor thin film according to claim 1, characterized in that: The substrate is a QST engineered substrate, which includes a stacked polycrystalline ceramic core, a barrier layer, a bonding layer, and the active silicon layer, and the first groove is arranged in the active silicon layer.
13. A semiconductor thin film, characterized in that: The semiconductor thin film is obtained by the preparation method according to any one of claims 1 to 12.
14. The semiconductor thin film according to claim 13, characterized in that: The semiconductor film is applied in the fields of acoustic wave resonator, light emitting diode, high electron mobility transistor, high mobility diode, MOSFET, UV-LED, photodetector, hydrogen generator or solar cell.