Preparation method of polycrystalline silicon thin film and transistor
By using a laser annealing method assisted by thermal and light absorbing layers in semiconductor devices, the problems of uneven crystallization and large leakage of polycrystalline silicon thin films are solved, and a higher performance semiconductor device is achieved.
Patent Information
- Application Number
- CN202411441015.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2025-02-11
AI Technical Summary
In semiconductor devices, the high defect density and low carrier mobility of the polycrystalline silicon thin film lead to poor transistor performance, especially when the channel width is small, and traditional laser annealing methods are difficult to achieve uniform grain size and low leakage.
By forming an amorphous silicon thin film on the semiconductor substrate and covering the thermal conduction layer and the light absorbing layer, the amorphous silicon thin film is converted into a polycrystalline silicon thin film by laser annealing. The light absorbing layer converts laser energy into heat, while the thermally conductive layer disperses and transfers it evenly to ensure the uniformity of polycrystalline silicon crystals.
The uniform crystallization of the polycrystalline silicon thin film is achieved, which reduces defect density and improves carrier mobility, reduces channel leakage, and improves the overall performance of semiconductor devices.
Smart Images
Figure CN119421475A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor process technology, and in particular to a method for preparing a polysilicon thin film and a transistor. Background Art
[0002] Single crystal silicon has been widely used in traditional processes because of its low defect density and high carrier mobility, which can provide good electrical conductivity. However, with the development of the semiconductor industry, when a higher integration density is required, it is usually necessary to design the CMOS (Complementary Metal-Oxide-Semiconductor Field-Effect Transistor) peripheral circuit below the storage circuit, which results in the transistor in the storage area can only use polysilicon as the channel. However, polysilicon has a high defect density and low carrier mobility, which will lead to poor transistor performance. Therefore, in the related art, in order to improve the performance of polysilicon, a thicker amorphous silicon film is usually deposited first, and then the grain size of polysilicon is increased by an annealing process, and finally the thickness is reduced by an etching process. However, this method cannot be used when the channel width is small. An alternative is to deposit a thin film of lower thickness and then perform laser annealing to increase the carrier mobility of the channel. In order to achieve laser annealing at every location, the laser beams need to overlap. In the overlapping areas, the grain size of the polysilicon will be larger and more uneven, and pinholes are likely to appear in the overlapping areas, resulting in greater channel leakage. Summary of the invention
[0003] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.
[0004] One aspect of the present application provides a method for preparing a polycrystalline silicon thin film, comprising: providing a semiconductor substrate, forming an amorphous silicon thin film on the semiconductor substrate; forming a heat-conducting layer covering the amorphous silicon thin film; forming a light-absorbing layer covering the heat-conducting layer; and performing laser annealing to convert the amorphous silicon thin film into a polycrystalline silicon thin film.
[0005] Exemplarily, the method for preparing a polycrystalline silicon thin film further includes: after the laser annealing, removing the light absorbing layer and the heat conducting layer.
[0006] Exemplarily, the heat-conducting layer includes a material with high thermal conductivity; wherein the material with high thermal conductivity includes at least one of tungsten, silver, copper, gold, iron, and aluminum.
[0007] Exemplarily, the heat conducting layer is formed by an electroplating process.
[0008] Exemplarily, the thickness of the heat-conducting layer is greater than the thickness of the light-absorbing layer.
[0009] Exemplarily, the light absorbing layer includes a high emissivity material; wherein the high emissivity material includes at least one of LSMO, LCMO, and SiC.
[0010] Exemplarily, the light absorbing layer is formed by a magnetron sputtering process.
[0011] Exemplarily, the thickness of the light absorbing layer is less than or equal to a critical thickness value; wherein the emissivity of the high emissivity material increases with increasing thickness.
[0012] Exemplarily, the light absorbing layer includes at least one of LSMO and LCMO; the method further includes: after the laser annealing treatment, removing the light absorbing layer by a wet etching process.
[0013] Another aspect of the present application also provides a method for preparing a transistor, wherein the transistor includes a gate structure, a gate dielectric structure and a channel structure, wherein the channel structure includes a polycrystalline silicon film, and the polycrystalline silicon film is prepared using the above-mentioned method for preparing a polycrystalline silicon film.
[0014] According to the method for preparing a polycrystalline silicon film and a transistor provided in the present application, the method for preparing a polycrystalline silicon film can convert laser energy into heat through a light absorbing layer during laser annealing, and then disperse and evenly transfer the heat to the amorphous silicon film through a heat conducting layer, thereby converting the amorphous silicon film into a polycrystalline silicon film and making the polycrystalline silicon crystallize evenly. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.
[0016] In the attached figure:
[0017] Figure 1 is a schematic diagram of a process for preparing a polycrystalline silicon thin film according to an embodiment of the present application;
[0018] Figure 2A-2E A schematic cross-sectional view of a device obtained by sequentially implementing a method for preparing a polycrystalline silicon thin film according to an exemplary embodiment of the present application is shown;
[0019] Figure 3 A schematic diagram showing an external radiation transparent or translucent material according to an embodiment of the present application;
[0020] Figure 4A schematic diagram of an external radiation opaque material according to an embodiment of the present application is shown;
[0021] Figure 5 A schematic diagram showing two adjacent laser beam irradiations according to an embodiment of the present application is shown. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.
[0023] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.
[0024] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art.
[0025] In order to thoroughly understand the present application, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present application. The optional embodiments of the present application are described in detail as follows, but in addition to these detailed descriptions, the present application may also have other implementation methods.
[0026] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0027] When semiconductor devices need to achieve higher storage density, the area occupied by peripheral circuits can be reduced through PUA (periphery under array) technology, but this method requires the storage area transistor to use polysilicon as the channel. Polysilicon has a higher defect density and lower carrier mobility, which will cause the performance of semiconductor devices to deteriorate. In order to reduce the defect density of polysilicon, laser annealing is usually used to increase the grain size of polysilicon. In the related art, in order to make the polysilicon grains in different areas the same size after annealing, a layer of metal film can be first deposited on the surface of the substrate, and then laser annealing is performed. After laser annealing, the metal film is removed. The metal film has the advantages of high thermal conductivity, but the metal film has a weak absorption capacity for lasers, and a strong reflection and transmission capacity. In particular, the transmitted light is very likely to cause different polysilicon grain sizes in different areas, resulting in uneven polysilicon crystallization on the semiconductor device.
[0028] In order to make the polysilicon on the transistor crystallize uniformly, the present application provides a method for preparing a polysilicon thin film, such as Figure 1 As shown, the method for preparing the polycrystalline silicon thin film includes:
[0029] Step S110: providing a semiconductor substrate, and forming an amorphous silicon thin film or an amorphous silicon thin film on the semiconductor substrate.
[0030] Step S120: forming a heat-conducting layer covering the amorphous silicon film.
[0031] Step S130: forming a light absorbing layer covering the heat conducting layer.
[0032] Step S140: laser annealing to transform the amorphous silicon film into a polycrystalline silicon film.
[0033] The method for preparing the polycrystalline silicon film in the embodiment of the present application can convert the laser energy into heat through the light absorbing layer during laser annealing, and then disperse the heat and evenly transfer it to the amorphous silicon film through the heat conducting layer, thereby converting the amorphous silicon film into a polycrystalline silicon film and making the polycrystalline silicon crystallize evenly, avoiding the difference in electric field distribution caused by different grain sizes and reducing leakage.
[0034] Embodiment 1
[0035] Below, reference FIG. 2A to FIG. 2E The method for preparing the polycrystalline silicon thin film of the present application is described in detail, wherein: FIG. 2A to FIG. 2E A schematic cross-sectional view of a device obtained by sequentially implementing the method for preparing a polycrystalline silicon thin film according to an embodiment of the present application is shown.
[0036] Exemplarily, the method for preparing the polycrystalline silicon thin film of the present application comprises the following steps:
[0037] First, step S110 is performed to provide a semiconductor substrate 100 to obtain Figure 2A The structure shown.
[0038] Exemplarily, the semiconductor substrate 100 can be any suitable semiconductor substrate, such as a silicon substrate, and can also be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP or other III / V compound semiconductors, including multilayer structures composed of these semiconductor materials, or silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI) and germanium on insulator (GeOI), or can also be double-sided polished silicon wafers (Double Side Polished Wafers, DSP), or can also be ceramic substrates such as alumina, quartz or glass substrates, etc.
[0039] As an example, first, the semiconductor substrate 100 is cleaned to remove oil, dust and other impurities on the surface, and the cleaning process may include multiple steps, such as soaking, rinsing and drying. Then, the cleaned semiconductor substrate 100 is polished to remove tiny scratches and uneven parts on the surface, thereby improving the surface flatness of the semiconductor substrate 100. The polishing method may include mechanical polishing and chemical mechanical polishing.
[0040] Afterwards Figure 2B As shown, a buffer layer 200 may be deposited on the semiconductor substrate 100. The buffer layer 200 can protect the semiconductor substrate 100 and provide a good growth interface for subsequent amorphous silicon.
[0041] For example, the material of the buffer layer 200 may include SiN x 、SiO x .
[0042] Then continue to execute step 110, such as Figure 2C As shown, an amorphous silicon thin film 300 is formed on a semiconductor substrate 100 .
[0043] For example, the amorphous silicon thin film 300 may be formed on the surface of the semiconductor substrate 100 by a deposition method such as chemical vapor deposition or plasma enhanced chemical vapor deposition.
[0044] Afterwards, the amorphous silicon film 300 may be immersed or sprayed with a nickel salt solution so that the nickel salt solution is evenly coated on the surface of the amorphous silicon film 300 .
[0045] Preferably, the amorphous silicon film 300 can be immersed or sputtered with a nickel salt solution with a nickel concentration of 1-1000 μg / mg to leave residual nickel on the surface of the amorphous silicon film 300. During subsequent laser annealing, nickel silicide formed by nickel and silicon serves as a seed crystal for crystallization of amorphous silicon, which can promote the transformation of amorphous silicon into polycrystalline silicon.
[0046] As an example, the semiconductor substrate 100 covered with the amorphous silicon film 300 may be placed in an annealing furnace for dehydrogenation treatment to reduce the hydrogen content in the amorphous silicon film to less than 3%, thereby avoiding hydrogen explosion during subsequent laser annealing treatment.
[0047] Next, step 120 is performed, such as Figure 2D As shown, a heat conducting layer 400 covering the amorphous silicon thin film 300 is formed.
[0048] For example, the heat-conducting layer 400 can be formed on the amorphous silicon film 300 by a method commonly used in the art, for example, the heat-conducting layer 400 can be formed by a physical vapor deposition process, a chemical vapor deposition process, an electroplating process, etc. Specifically, the heat-conducting layer 400 includes a high thermal conductivity material; wherein the high thermal conductivity material includes at least one of tungsten, silver, copper, gold, iron, and aluminum. Specifically, the thickness of the heat-conducting layer 400 can range from 400 to 600 nm.
[0049] In one example, metal atoms or molecules can be transferred from a source material and coated onto the amorphous silicon film 300 by a physical process (such as evaporation, sputtering, etc.). A metal film can also be generated in a gaseous state by a chemical reaction, and deposited on the amorphous silicon film 300 to form a thermal conductive layer 400 covering the amorphous silicon film 300. An electric field can also be applied to an electrolyte so that metal ions are deposited on the amorphous silicon film 300 under the action of the electric field to form a thermal conductive layer 400 covering the amorphous silicon film 300.
[0050] It should be noted that for transparent or translucent materials, such as Figure 3 As shown in Figure 1, when irradiated by external radiation, part of the energy is reflected by the transparent or translucent material, part of the energy is absorbed by the transparent or translucent material, and part of the energy passes through the transparent or translucent material. Specifically, it can be expressed by the formula α+β+γ=1. For opaque materials, such as Figure 4 As shown, when irradiated by external radiation, part of the energy is reflected by the opaque material, and part of the energy is absorbed by the opaque material. Specifically, it can be expressed by the formula α+γ=1. Among them, α represents the reflectance, β represents the transmittance, and γ represents the absorption ratio.
[0051] For metal films, since the metal material has a low emissivity, it absorbs the laser beam weakly. In the case of thin films, a large amount of laser light is either reflected or directly passes through the metal film. Figure 5 As shown in the figure, there is an overlapping area between two adjacent irradiations of the laser beam. The laser annealing laser directly passes through the metal film to reach the amorphous silicon, which is one of the direct reasons for the increase in grain size in the overlapping area of the laser annealing scan. Only the absorbed energy is converted into lattice vibration and heats the amorphous silicon through heat conduction. Therefore, the metal film has good thermal conductivity, but the laser absorption ability is weak and the laser beam is easy to penetrate.
[0052] The present application then performs step S130, such as Figure 2E As shown, a light absorbing layer 500 covering the heat conducting layer 400 is formed.
[0053] Exemplarily, the thickness of the heat conductive layer 400 is greater than the thickness of the light absorbing layer 500 .
[0054] For example, the light absorbing layer 500 can be formed on the surface of the heat conducting layer 400 by a method commonly used in the art, for example, the light absorbing layer 500 can be formed by a physical vapor deposition process, a chemical vapor deposition process, a magnetron sputtering process, etc. Specifically, the light absorbing layer 500 includes a high emissivity material, and the laser beam can hardly pass through the high emissivity material. The high emissivity material includes at least LSMO (LaSr x Mn 1-X O), LCMO (LaCa x Mn 1-x More specifically, the light absorbing layer 500 may have a thickness ranging from 400 nm to 600 nm.
[0055] Specifically, the thickness of the light absorbing layer 500 is less than or equal to the critical thickness value; wherein the emissivity of the high emissivity material increases with increasing thickness. It should be noted that the critical thickness value indicates that when the thickness of the light absorbing layer 500 reaches a certain value, the increasing trend of the emissivity of the high emissivity material begins to slow down or does not change much. Below the critical thickness value, as the thickness of the high emissivity material increases, the light absorbing layer 500 can more effectively absorb laser energy and convert it into heat. When the thickness of the high emissivity material exceeds the critical thickness value, although the emissivity remains at a high level, the effect of increasing the thickness becomes less obvious.
[0056] Next, taking LSMO as an example, the formation process of the light absorbing layer 500 is described: first, select La2O3, SrCO3 and MnO2 powders with high purity and mix them thoroughly, pour the mixed powders into a mold for pressing to form a target blank with a certain shape, put the pressed target blank into a high-temperature furnace, pre-sinter at a temperature of 600-800°C, put the pre-sintered target blank into a high-temperature furnace, and calcine at a temperature of 1100-1400°C to form a target. Finally, a thin film is deposited by a magnetron sputtering method to form a light absorbing layer 500 covering the thermal conductive layer 400.
[0057] It should be noted that according to Kirchhoff's law, high emissivity materials have high electromagnetic wave absorption rates and strong absorption capacity for lasers. If the high emissivity material is directly covered on the amorphous silicon film 300, the polysilicon grains in the overlapping area of the laser beam will be larger after the laser beam is scanned, while the grains in the non-overlapping area will be smaller. The formation of large grains requires the participation of more silicon atoms, which will cause local non-uniformity in the amorphous silicon film 300 during the shrinkage process, and pinholes and sharp corners may appear, resulting in large leakage between the gate and the polysilicon channel.
[0058] In this step, after the high emissivity material is formed on the surface of the thermal conductive layer 400, the laser absorption capacity of the wafer surface is close to that of a black body, and the energy of the laser beam can be almost completely absorbed. After the energy is absorbed, it can be considered that there is no transmission and reflection. The energy absorbed by the high emissivity material will be converted into phonon vibration, and then the heat will be transferred to the thermal conductive layer 400. Finally, the high thermal conductivity effect of the high thermal conductivity material is used to disperse the heat and reduce the difference in grain size in different areas.
[0059] Next, step 140 is performed: laser annealing treatment is performed to transform the amorphous silicon film 300 into a polycrystalline silicon film.
[0060] Specifically, laser annealing utilizes the high energy density and rapid heating characteristics of the laser beam to locally heat the amorphous silicon film 300 on the semiconductor substrate 100. In a very short time, the laser beam can heat the amorphous silicon to a melting or near-melting temperature, and then rapidly cool the silicon atoms to rearrange them to form an ordered crystal structure, thereby obtaining a polycrystalline silicon film with uniform crystallization. Laser annealing is a commonly used heat treatment method in the art, and this application will not elaborate on it here.
[0061] Next, step S150 is performed: after laser annealing, the light absorbing layer 500 and the heat conducting layer 400 are removed.
[0062] Exemplarily, the light absorbing layer 500 includes at least one of LSMO and LCMO, and the light absorbing layer 500 can be removed by wet etching (using a chemical solution to dissolve the light absorbing layer material) or dry etching; the heat conducting layer 400 can be removed by wet etching (using a specific chemical solution to dissolve the metal) or mechanical grinding (such as chemical mechanical polishing, etc.). The above-mentioned etching method for removing the light absorbing layer 500 and the heat conducting layer 400 is a commonly used etching method in the art, and this application will not be discussed in detail here.
[0063] The key steps of the method for preparing the polysilicon thin film of the present application have been introduced so far. The complete polysilicon thin film manufacturing may also require multiple other process steps, which will not be described one by one here.
[0064] It is worth mentioning that the order of the above steps is only an example. Under the premise of no conflict, the order of the above steps can also be swapped or performed alternately.
[0065] Embodiment 2
[0066] The present application also provides a method for preparing a transistor, the transistor includes a gate structure, a gate dielectric structure and a channel structure, the channel structure includes a polycrystalline silicon film, and the polycrystalline silicon film is prepared by the above-mentioned method for preparing a polycrystalline silicon film.
[0067] Exemplarily, the transistor can be used in electronic devices, which can be any electronic products or equipment such as mobile phones, tablet computers, laptops, netbooks, game consoles, televisions, VCDs, DVDs, navigators, cameras, camcorders, voice recorders, MP3s, MP4s, PSPs, etc.
[0068] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.
[0069] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.
[0070] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.
[0071] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.
[0072] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.
[0073] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.
[0074] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.
[0075] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some modules according to the embodiments of the present application. The application can also be implemented as a device program (e.g., computer program and computer program product) for executing a part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.
[0076] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.
[0077] The above is only a specific implementation or description of a specific implementation of the present application, and the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. A method for preparing a polycrystalline silicon thin film, characterized in that: include: Providing a semiconductor substrate, and forming an amorphous silicon thin film on the semiconductor substrate; forming a heat-conducting layer covering the amorphous silicon thin film; forming a light absorbing layer covering the heat conductive layer; Laser annealing is performed to transform the amorphous silicon film into a polycrystalline silicon film.
2. The method for preparing a polycrystalline silicon thin film according to claim 1, wherein: Also includes: After the laser annealing, the light absorbing layer and the heat conducting layer are removed.
3. The method for manufacturing a polycrystalline silicon thin film according to claim 1, wherein: The heat-conducting layer comprises a high thermal conductivity material; Wherein, the high thermal conductivity material includes at least one of tungsten, silver, copper, gold, iron and aluminum.
4. The method for manufacturing a polycrystalline silicon thin film according to claim 3, wherein: The heat conducting layer is formed by an electroplating process.
5. The method for manufacturing a polycrystalline silicon thin film according to claim 3, wherein: The thickness of the heat-conducting layer is greater than the thickness of the light-absorbing layer.
6. The method for manufacturing a polycrystalline silicon thin film according to claim 1, wherein: The light absorbing layer comprises a high emissivity material; Wherein, the high emissivity material includes at least one of LSMO, LCMO and SiC.
7. The method for manufacturing a polycrystalline silicon thin film according to claim 6, wherein: The light absorbing layer is formed by a magnetron sputtering process.
8. The method for manufacturing a polycrystalline silicon thin film according to claim 6, wherein: The thickness of the light absorbing layer is less than or equal to a critical thickness value; The emissivity of the high emissivity material increases with increasing thickness.
9. The method for manufacturing a polycrystalline silicon thin film according to claim 6, wherein: The light absorbing layer comprises at least one of LSMO and LCMO; the method further comprises: After the laser annealing process, the light absorbing layer is removed by a wet etching process.
10. A method for preparing a transistor, characterized in that: The transistor includes a gate structure, a gate dielectric structure and a channel structure. The channel structure includes a polysilicon thin film. The polysilicon thin film is prepared by the method for preparing a polysilicon thin film according to any one of claims 1 to 9.