Method for producing group iv compound epitaxial alloy thin films

Abstract

The application discloses a preparation method of a group IV compound epitaxial alloy thin film. It relates to the technical field of semiconductor alloy thin film growth, and comprises the following steps: placing initial silicon single crystal particles and target doped group IV metal single crystal particles with a preset atomic mole ratio on the surface of a reaction substrate; after a target vacuum degree and a target heating temperature are reached in a preparation device, the target doped group IV metal single crystal particles become a molten state, a target metal solution is obtained, the initial silicon single crystal particles are dissolved in the target metal solution, and a reaction metal solution is formed; a carrier gas and a carbon-containing reaction gas are introduced into the preparation device, the carbon-containing reaction gas contacts the surface of the reaction metal solution and is cracked to form carbon reaction atoms, the carbon reaction atoms diffuse and react in the reaction metal solution, and a group IV compound epitaxial alloy thin film is formed. Through the application, the problem that an epitaxial multi-component alloy thin film with high metal concentration, controllable composition and good crystal quality cannot be obtained in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of semiconductor alloy thin film growth technology, and more specifically, to a method for preparing a group IV compound epitaxial alloy thin film. Background Technology

[0002] Silicon-silicon-germanium (SiC), silicon-silicon-tin (SiC), and silicon-silicon-lead (SiC-lead) alloys, as ternary semiconductor materials based on silicon carbide (SiC), possess core advantages stemming from the isoelectronic doping or alloying effects of germanium (Ge), tin (Sn), and lead (Pb). They combine the high thermal stability and wide bandgap of SiC with the ability to control the atomic size and electronic structure of Ge, Sn, and Pb, exhibiting unique value in crystal quality optimization, strain engineering, and device performance enhancement. For example, they can optimize device electrical parameters, such as reducing contact resistance and increasing transistor gain. They can also be used to fabricate high-performance power devices and high-frequency transistors, suitable for applications with extremely high requirements for device efficiency and reliability, such as aerospace electronics and ultra-high-voltage power transmission. Existing methods for preparing SiC-germanium / SiC-tin / SiC-lead alloys mainly rely on chemical vapor deposition (CVD) for alloying. However, limitations in the thermal decomposition efficiency of the gas source, differences in the reactivity between elements, and solid solubility make it difficult to achieve high-concentration and uniform alloy synthesis.

[0003] There is currently no effective solution to the problem that the low solid-phase reaction rate and limited gas-phase pathway in related technologies make it impossible to obtain epitaxial multi-element alloy thin films with high metal concentration, controllable composition, and good crystal quality. Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing epitaxial alloy thin films of group IV compounds, so as to solve the problem in related technologies that it is still impossible to obtain epitaxial multi-element alloy thin films with high metal concentration, controllable composition and good crystal quality due to low solid-phase reaction rate and limited gas phase path.

[0005] To achieve the above objectives, one embodiment of this application provides a method for preparing a group IV compound epitaxial alloy thin film, comprising:

[0006] After surface treatment of the reaction substrate, the reaction substrate is fixed at the bottom of the preparation device;

[0007] Initial silicon single crystal particles and target doped group IV metal single crystal particles with a predetermined atomic molar ratio are placed on the surface of the reaction substrate, wherein the ratio of the molar number of the initial silicon single crystal particles to the molar number of the target doped group IV metal single crystal particles is less than 1:9.

[0008] When the vacuum control system and heating system are turned on, and the target vacuum level and target heating temperature are reached in the preparation device, the target doped Group IV metal single crystal particles become molten and a target metal solution is obtained. The initial silicon single crystal particles dissolve in the target metal solution to form a reaction metal solution, wherein the reaction metal solution contains target doped Group IV metal atoms and silicon atoms.

[0009] A carrier gas and a carbon-containing reactive gas are introduced into the preparation apparatus. After the carbon-containing reactive gas comes into contact with the surface of the reaction metal solution, it decomposes to form carbon reactive atoms. The carbon reactive atoms diffuse and react in the reaction metal solution to form a group IV compound epitaxial alloy thin film on the reaction substrate.

[0010] Optionally, forming a group IV compound epitaxial alloy thin film on the reaction substrate specifically includes:

[0011] A carrier gas and a carbon-containing reactive gas are introduced into the preparation device. The carbon-containing reactive gas undergoes pyrolysis upon contact with the surface of the reaction metal solution, forming carbon reactive atoms. The carbon reactive atoms diffuse and react in the reaction metal solution. The carbon-containing reactive gas is composed of hydrocarbons.

[0012] The carbon atoms in the reactive metal solution combine with the silicon atoms in the reactive metal solution to form an epitaxial matrix;

[0013] The target doped Group IV metal atoms in the reactive metal solution enter the epitaxial matrix to form a Group IV compound epitaxial alloy thin film, wherein the target doped Group IV metal atoms replace silicon atoms in a portion of the crystal lattice of the Group IV compound epitaxial alloy thin film.

[0014] Optionally, the target doped Group IV metal atoms in the reactive metal solution enter the epitaxial matrix to form a Group IV compound epitaxial alloy thin film, specifically including:

[0015] During the growth of the epitaxial substrate, the target doped Group IV metal atoms in the reactive metal solution replace some of the silicon atoms in the epitaxial substrate through substitutional solid solution, thereby obtaining a Group IV compound epitaxial alloy thin film.

[0016] Optionally, the target doped group IV metal single crystal particles include germanium single crystal particles, tin single crystal particles, or lead single crystal particles, and the final alloy is a carbon-silicon-germanium alloy, a carbon-silicon-tin alloy, or a carbon-silicon-lead alloy.

[0017] Optionally, the target vacuum level is 10. -5 Below Pa, the target heating temperature is between the melting point of the target doped Group IV metal single crystal particle and the decomposition temperature of the reaction substrate.

[0018] Optionally, the target heating temperature ranges from 800 degrees Celsius to 2000 degrees Celsius.

[0019] Optionally, the flow rate ratio of the carrier gas to the carbon-containing reactant gas is less than 8:50, the carrier gas is hydrogen or argon, and the carbon-containing reactant gas includes one or more of methane, ethylene, propane, propylene, butane, and butene.

[0020] Optionally, after forming a group IV compound epitaxial alloy thin film on the reaction substrate, the method further includes: after the epitaxial alloy thin film cools to room temperature, removing the residual reactants on the surface of the group IV compound epitaxial alloy thin film. The specific steps include: after the reaction is completed and the temperature in the preparation device cools to room temperature, taking out the group IV compound epitaxial alloy thin film from the preparation device and immersing it in a mixed solution of hydrofluoric acid and nitric acid to remove the residual reactants on the surface.

[0021] Optionally, the reaction substrate includes one of a silicon carbide substrate, a silicon substrate, and a silicon-germanium substrate.

[0022] The beneficial effects of this application are:

[0023] This application employs the following steps: Initial silicon single crystal particles and target doped Group IV metal single crystal particles with a predetermined atomic molar ratio are placed on the surface of a reaction substrate; after reaching the target vacuum level and target heating temperature within the preparation apparatus, the target doped Group IV metal single crystal particles become molten, yielding a target metal solution, in which the initial silicon single crystal particles dissolve, forming a reaction metal solution; a carrier gas and a carbon-containing reactive gas are introduced into the preparation apparatus; upon contact with the surface of the reaction metal solution, the carbon-containing reactive gas decomposes, forming carbon-carbon reactive atoms that diffuse and react in the reaction metal solution, forming a Group IV compound epitaxial alloy thin film on the reaction substrate. This application, by controlling the initial silicon single crystal particles and target doped Group IV metal single crystal particles with a predetermined atomic molar ratio, solves the problem in related technologies where low solid-phase reaction rates and limited gas-phase pathways prevent the preparation of epitaxial multi-element alloy thin films with high metal concentration, controllable composition, and good crystal quality, thereby achieving the effect of preparing high-quality epitaxial alloy thin films. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In addition, in the following drawings, the components are not necessarily drawn to scale, and components with similar related characteristics or features may have the same or similar reference numerals.

[0025] Figure 1 This is a flowchart illustrating the preparation method of group IV compound epitaxial alloy thin films provided in some embodiments of this application;

[0026] Figure 2 This is a schematic diagram of the apparatus for preparing group IV compound epitaxial alloy thin films provided in some embodiments of this application.

[0027] In the figure: 1 is the reaction substrate, 2 is the target metal solution, 3 is the vacuum control system, 4 is the reaction gas inlet system, 5 is the reaction chamber, 6 is the heater, 7 is the graphite crucible, and 8 is the graphite base. Detailed Implementation

[0028] To make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, the following describes this application in further detail with reference to the accompanying drawings and embodiments.

[0029] In the description of this application, it should be noted that the use of terms such as "first" and "second" to define objects (such as elements, components, regions, layers, doping types and / or parts) is merely for the purpose of distinguishing different objects and is not necessarily used to describe a specific order or sequence. Unless the context clearly indicates otherwise, it should be understood that such data can be used interchangeably where appropriate.

[0030] In the description of this application, it should be understood that the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “compose” and / or “comprise” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0031] In the description of this application, it should also be noted that when a component is referred to as "on another component," "connected to another component," or "in contact with another component," it can mean not only that a component is directly on, directly connected to, or directly in contact with another component, but also that an intermediate component can be inserted between the two components. Furthermore, "connection" includes not only fixed connections but also detachable connections or integral connections. Similarly, when an element is referred to as "electrically connected," "electrically contacted," "electrically coupled," or "electrically coupled to" another element, the two elements can be in direct electrical contact or point coupling, or they can be in electrical contact or point coupling through an intermediate component.

[0032] In the description of this application, it should also be noted that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0033] Furthermore, in the description of this application, spatial relation terms such as "below," "under," "below," "below," "below," "above," "on the upper surface of," "above," etc., can be used to describe the spatial positional relationship between one element or feature shown in the figures and other elements or features. It should be understood that spatial relation terms, in addition to the orientation shown in the figures, also include different orientations of elements or features in use and operation. For example, if an element or feature in the figures is flipped or inverted, an element or feature described as "below" or "below" other elements or features will be oriented "above" other elements or features. Furthermore, elements may also include other orientations (e.g., rotated by an angle or other orientations).

[0034] In the related technologies for preparing carbon-silicon-germanium, carbon-silicon-tin, and carbon-silicon-lead epitaxial alloy thin films, the inventors first tried two methods: ion implantation and chemical vapor deposition (CVD).

[0035] Ion implantation involves bombarding the surface of silicon carbide with high-energy ions (such as germanium, tin, or lead ions) to embed them into the silicon carbide lattice, thereby doping the epitaxial film with metal atoms. However, this method has drawbacks: First, when large doses of germanium, tin, or lead ions are implanted, these ions not only replace the lattice sites of silicon atoms in silicon carbide but also knock away a large number of silicon atoms through a "collision cascade effect," forming point defects and extended defects such as vacancies, interstitial atoms, and dislocation loops. Second, the radii of germanium, tin, or lead atoms are much larger than those of Si, and large-dose implantation exacerbates lattice distortion, preventing some germanium, tin, or lead atoms from occupying lattice sites and instead forming interstitial impurity clusters. These defects (especially clusters) can cause lattice damage and deep-level defect generation in the band gap (e.g., interstitial atoms of germanium atoms may form deep donor levels of 0.5eV-0.8eV in the silicon carbide band gap), becoming efficient recombination centers for charge carriers. Finally, there are limitations in annealing repair. While epitaxial films can eliminate some defects that occur during epitaxial film growth through high-temperature annealing, the damage caused by large-dose implantation of germanium, tin, or lead ions is difficult to eliminate by annealing repair. Furthermore, germanium, tin, or lead atoms are prone to diffuse at high temperatures to form secondary clusters, which will exacerbate the defect problem.

[0036] Chemical vapor deposition (CVD) epitaxy aims to dope germanium, tin, or lead into epitaxial films using high concentrations of germanium-based, tin-based, or lead-based reactive gases. However, this method has several drawbacks: First, high concentrations of these gases can agglomerate into metal droplets on the epitaxial film. These droplets continuously absorb germanium, tin, or lead atoms from the gas phase, eventually forming larger droplets that disrupt the continuity of the epitaxial film. Second, high concentrations of these gases increase the surface energy barrier, transforming the step-flow growth mode (ideally smooth growth) into an island-like growth mode, further exacerbating surface undulations. Finally, the formation of metal droplets is often accompanied by localized enrichment of germanium, tin, or lead atoms, resulting in an "island-like" fluctuation in the doping concentration distribution of germanium, tin, or lead atoms in the epitaxial film, rather than an ideal uniform distribution. This can cause spatial fluctuations in carrier concentration, reducing the consistency of device performance.

[0037] Both of the above methods have significant limitations. Therefore, the inventors have proposed a new method to obtain epitaxial alloy thin films with controllable composition and good crystal quality.

[0038] According to embodiments of this application, a method for preparing a group IV compound epitaxial alloy thin film is provided.

[0039] Figure 1This is a flowchart illustrating a method for preparing a group IV compound epitaxial alloy thin film according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0040] Step S101: After surface treatment of the reaction substrate, the reaction substrate is fixed at the bottom of the preparation device.

[0041] It should be noted that the reaction substrate can be a silicon carbide substrate, such as cubic silicon carbide, tetragonal silicon carbide, and hexagonal silicon carbide. In other embodiments, the reaction substrate can also be a silicon substrate or a silicon-germanium substrate. In the semiconductor epitaxial growth or thin film deposition process, the substrate is the base material that supports the epitaxial layer, and its main function is to provide the source of the lattice template.

[0042] The preparation apparatus refers to the entire experimental system used to complete the epitaxial alloy thin film, including: a reaction chamber, a gas inlet or material supply system, a heating or temperature control system, a pressure control and vacuum system, a substrate support, and an exhaust and by-product treatment unit. In the embodiments of this application, a graphite crucible is placed at the center of the bottom of the preparation apparatus, and the preparation base is a graphite base.

[0043] The surface treatment of the reaction substrate typically includes cleaning, descaling, oxide removal, planarization, etching, and preheating, with the aim of obtaining a clean, ordered, and active reaction surface to ensure high-quality growth of the epitaxial alloy film.

[0044] Step S102: Place initial silicon single crystal particles and target doped group IV metal single crystal particles with a preset atomic molar ratio on the surface of the reaction substrate, wherein the ratio of the molar number of the initial silicon single crystal particles to the molar number of the target doped group IV metal single crystal particles is less than 1:9.

[0045] It should be noted that the purpose of this invention is to form a group IV compound epitaxial alloy thin film, and the corresponding semiconductor compound is silicon carbide. Therefore, initial silicon single crystal particles and target doped group IV metal single crystal particles with a preset atomic molar ratio are placed on the surface of the reaction substrate. In this embodiment, the target doped group IV metal single crystal particles can be: germanium single crystal particles, tin single crystal particles, lead single crystal particles, or other single crystal particles of elements in the same group as silicon.

[0046] The ratio of the molar number of the initial silicon single crystal particles to the molar number of the target doped group IV metal single crystal particles can be less than 1:9.

[0047] In one embodiment, the molar ratio of silicon single crystal particles to germanium single crystal particles is less than 1:9, or the molar ratio of silicon single crystal particles to tin single crystal particles is less than 1:9, or the molar ratio of silicon single crystal particles to lead single crystal particles is less than 1:9. This means that each initial silicon single crystal particle corresponds to more than 9 target doped Group IV metal single crystal particles. In this case, the silicon-germanium solution, silicon-tin solution, or silicon-lead solution is a liquid phase environment dominated by germanium, tin, or lead. Due to the low silicon content, when the concentration of silicon atoms cannot provide sufficient local concentration to form silicon-carbon chemical bonds, germanium atoms, tin atoms, or lead atoms will preferentially deposit and enter the epitaxial alloy film.

[0048] This invention solves the problem in related technologies of being unable to obtain epitaxial multi-element alloy thin films with high metal concentration, controllable uniform composition, and good crystal quality by controlling the initial silicon single crystal particles and the target doped group IV metal single crystal particles with a preset atomic molar ratio.

[0049] Step S103: The vacuum control system and heating system are turned on. When the target vacuum level and target heating temperature are reached in the preparation device, the target doped Group IV metal single crystal particles become molten and the target metal solution is obtained. The initial silicon single crystal particles dissolve in the target metal solution to form a reaction metal solution, wherein the reaction metal solution contains target doped Group IV metal atoms and silicon atoms.

[0050] It should be noted that the vacuum control system refers to the system used for evacuation, maintaining and regulating the pressure within the reaction chamber. Its function is to remove impurity gases, provide a controllable environment, and regulate gas pressure, thereby improving the film quality. The heating system refers to the system used in the reaction chamber to heat the substrate and reaction zone. Its function is to provide energy, promote diffusion and nucleation, control the epitaxial mode, and assist annealing, thereby promoting the high-quality growth of epitaxial alloy thin films.

[0051] Specifically, the vacuum control system is first turned on to achieve the target vacuum level in the preparation device. Then, an inert gas is introduced to maintain the chamber pressure within a certain range. At this point, the heating system is turned on to bring the internal temperature of the preparation device to the target heating temperature. When the internal temperature of the preparation device exceeds the melting point of the target doped single crystal particles, the target doped group IV metal single crystal particles become molten, resulting in the target metal solution. The initial silicon single crystal particles dissolve in the target metal solution to form a reactive metal solution.

[0052] Furthermore, the target doped group IV metal single crystal particles include: germanium single crystal particles, tin single crystal particles, or lead single crystal particles. When the target vacuum level within the fabrication apparatus is 10... -5Below Pa, an inert gas is introduced to maintain the chamber pressure between 50 mbar and 900 mbar. Then, the heating system is turned on until the melting point of germanium single crystal particles, tin single crystal particles, or lead single crystal particles is exceeded. The germanium single crystal particles, tin single crystal particles, or lead single crystal particles become molten, and the target metal solution of germanium solution, tin solution, or lead solution is obtained. The initial silicon single crystal particles will dissolve in the target metal solution to form a reaction metal solution of silicon-germanium solution, silicon-tin solution, or silicon-lead solution.

[0053] The target heating temperature is between the melting point of the target doped group IV metal single crystal particles and the decomposition temperature of the reaction substrate.

[0054] In this embodiment of the application, the target heating temperature ranges from 800 degrees Celsius to 2000 degrees Celsius, such as 950 degrees Celsius, 1100 degrees Celsius, or 1400 degrees Celsius.

[0055] In step S104, a carrier gas and a carbon-containing reactive gas are introduced into the preparation device. The carbon-containing reactive gas undergoes pyrolysis upon contact with the surface of the reaction metal solution, forming carbon reactive atoms. These carbon reactive atoms diffuse and react in the reaction metal solution, forming a group IV compound epitaxial alloy thin film on the reaction substrate.

[0056] It should be noted that the carbon-containing reactive gas refers to the gas introduced into the reaction chamber as a reaction source during the preparation of the epitaxial alloy thin film. Under certain conditions, it decomposes or provides carbon elements, which are deposited on the substrate surface to form the silicon-carbon epitaxial alloy thin film. The reactive gas needs to be introduced together with the carrier gas. The purpose of introducing the reactive gas together is to dilute the reactive gas, act as a gas transport carrier, and stabilize the reaction environment, ensuring that the epitaxial alloy thin film forms at a controllable rate.

[0057] In the embodiments of this application, the flow rate ratio of the carrier gas to the carbon-containing reactive gas is less than 8:50. The carrier gas is hydrogen or argon, and the carbon-containing reactive gas can be one or more of methane, ethylene, propane, propylene, butane, and butene.

[0058] When the target doped Group IV metal atom is germanium, the epitaxial alloy film formed is mainly composed of silicon-carbon germanium alloy because germanium occupies lattice sites of silicon in the silicon carbide lattice, while the other components are silicon carbide. When the target doped Group IV metal atom is tin, the epitaxial alloy film formed is mainly composed of silicon-carbon tin alloy because tin occupies lattice sites of silicon in the silicon carbide lattice, while the other components are silicon carbide. When the target doped Group IV metal atom is lead, the epitaxial alloy film formed is mainly composed of silicon-carbon lead alloy because lead occupies lattice sites of silicon in the silicon carbide lattice, while the other components are silicon carbide.

[0059] When carbon-containing reactive gases come into contact with the surface of the reactive metal solution, they undergo pyrolysis, forming carbon reactive atoms. Pyrolysis refers to the decomposition of compounds under high temperature or specific catalytic surface conditions, breaking the original chemical bonds and generating simpler molecules or atoms. The carbon reactive atoms formed by pyrolysis dissolve into the reactive metal solution, where they diffuse and react with silicon atoms to form an epitaxial matrix. Because the silicon content in the reactive metal solution is relatively low, the target doped Group IV metal atoms can more easily replace silicon atoms in the epitaxial matrix through substitutional solid solution, resulting in a Group IV compound epitaxial alloy thin film.

[0060] After forming a group IV compound epitaxial alloy thin film on the reaction substrate, the method further includes: after the group IV compound epitaxial alloy thin film cools to room temperature, removing the residual reactants on the surface of the group IV compound epitaxial alloy thin film. The specific steps include: after the reaction is completed and the temperature in the preparation device cools to room temperature, taking out the group IV compound epitaxial alloy thin film from the preparation device and immersing it in a mixed solution of hydrofluoric acid and nitric acid to remove the residual reactants on the surface.

[0061] It should be noted that surface residual reactants refer to unwanted substances that adhere to the surface of the epitaxial alloy film during the cooling or deposition process. These mainly consist of a solid mixture of unreacted initial silicon single crystal particles and target doped group IV metal single crystal particles, as well as particulate contamination.

[0062] After the epitaxial alloy film is grown, it is first allowed to cool naturally to room temperature. Then, the film surface is cleaned to remove the reactants remaining during the deposition process, so as to obtain a purer epitaxial alloy film.

[0063] This invention also provides a group IV compound epitaxial alloy thin film, utilizing, for example... Figure 2 The apparatus shown was prepared using the method described above for preparing a group IV compound epitaxial alloy thin film.

[0064] The specific preparation steps are as follows:

[0065] After surface treatment of the reaction substrate 1, the reaction substrate 1 is fixed on the graphite crucible 7, the graphite crucible 7 is placed above the graphite base 8, and the graphite base 8 is located at the bottom of the preparation device.

[0066] Initial silicon single crystal particles and target doped group IV metal single crystal particles with a preset atomic molar ratio are placed on the surface of the reaction substrate 1, wherein the ratio of the molar number of the initial silicon single crystal particles to the molar number of the target doped group IV metal single crystal particles is less than 1:9.

[0067] When the vacuum control system 3 and heater 6 are turned on, and the target vacuum level and target heating temperature are reached in the preparation device, the target doped group IV metal single crystal particles become molten and the target metal solution 2 is obtained. For example, the target metal solution 2 can be a silicon-germanium solution, a silicon-tin solution or a silicon-lead solution. The initial silicon single crystal particles dissolve in the target metal solution 2 to form a reaction metal solution, wherein the reaction metal solution contains target doped group IV metal atoms and silicon atoms.

[0068] Carrier gas and carbon-containing reactive gas are introduced into the preparation device through the reactive gas inlet system 4. After the carbon-containing reactive gas comes into contact with the surface of the reactive metal solution in the reaction chamber 5, it decomposes to form carbon reactive atoms. The carbon reactive atoms diffuse and react in the reactive metal solution to form a group IV compound epitaxial alloy thin film on the reaction substrate 1.

[0069] It should be noted that, where there is no conflict, the features in the different embodiments of this application described above can be combined with each other. Furthermore, in each of the above embodiments, the focus is on describing the differences from other embodiments; other specific descriptions of the same / similar parts between the embodiments can be referred to (or referenced) interchangeably. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this application.

[0070] Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

Claims

1. A method for preparing a group IV compound epitaxial alloy thin film, characterized in that, include: After surface treatment of the reaction substrate, the reaction substrate is fixed at the bottom of the preparation device; Initial silicon single crystal particles and target doped group IV metal single crystal particles with a predetermined atomic molar ratio are placed on the surface of the reaction substrate, wherein the ratio of the molar number of the initial silicon single crystal particles to the molar number of the target doped group IV metal single crystal particles is less than 1:

9. When the vacuum control system and heating system are turned on, and the target vacuum level and target heating temperature are reached in the preparation device, the target doped Group IV metal single crystal particles become molten and a target metal solution is obtained. The initial silicon single crystal particles dissolve in the target metal solution to form a reaction metal solution, wherein the reaction metal solution contains target doped Group IV metal atoms and silicon atoms. A carrier gas and a carbon-containing reactive gas are introduced into the preparation apparatus. After the carbon-containing reactive gas comes into contact with the surface of the reaction metal solution, it decomposes to form carbon reactive atoms. The carbon reactive atoms diffuse and react in the reaction metal solution to form a group IV compound epitaxial alloy thin film on the reaction substrate.

2. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, Forming a group IV compound epitaxial alloy thin film on the reaction substrate specifically includes: A carrier gas and a carbon-containing reactive gas are introduced into the preparation device. The carbon-containing reactive gas undergoes pyrolysis upon contact with the surface of the reaction metal solution, forming carbon reactive atoms. The carbon reactive atoms diffuse and react in the reaction metal solution. The carbon-containing reactive gas is composed of hydrocarbons. The carbon atoms in the reactive metal solution combine with the silicon atoms in the reactive metal solution to form an epitaxial matrix; The target doped Group IV metal atoms in the reactive metal solution enter the epitaxial matrix to form a Group IV compound epitaxial alloy thin film, wherein the target doped Group IV metal atoms replace silicon atoms in a portion of the crystal lattice of the Group IV compound epitaxial alloy thin film.

3. The method for preparing group IV compound epitaxial alloy thin films according to claim 2, characterized in that, The target group IV metal atoms in the reactive metal solution enter the epitaxial matrix to form a group IV compound epitaxial alloy thin film, specifically including: During the growth of the epitaxial substrate, the target doped Group IV metal atoms in the reactive metal solution replace some of the silicon atoms in the epitaxial substrate through substitutional solid solution, thereby obtaining a Group IV compound epitaxial alloy thin film.

4. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, The target doped group IV metal single crystal particles include germanium single crystal particles, tin single crystal particles, or lead single crystal particles, and the final alloy is a carbon-silicon-germanium alloy, a carbon-silicon-tin alloy, or a carbon-silicon-lead alloy.

5. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, The target vacuum level is 10. -5 Below Pa, the target heating temperature is between the melting point of the target doped group IV metal single crystal particles and the decomposition temperature of the reaction substrate.

6. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, The target heating temperature ranges from 800 degrees Celsius to 2000 degrees Celsius.

7. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, The flow rate ratio of the carrier gas to the carbon-containing reactive gas is less than 8:

50. The carrier gas is hydrogen or argon, and the carbon-containing reactive gas includes one or more of methane, ethylene, propane, propylene, butane, and butene.

8. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, After forming a group IV compound epitaxial alloy thin film on the reaction substrate, the method further includes: after the group IV compound epitaxial alloy thin film cools to room temperature, removing the residual reactants on the surface of the group IV compound epitaxial alloy thin film. The specific steps include: after the reaction is completed and the temperature in the preparation device cools to room temperature, taking out the group IV compound epitaxial alloy thin film from the preparation device and immersing it in a mixed solution of hydrofluoric acid and nitric acid to remove the residual reactants on the surface.

9. The method for preparing group IV compound epitaxial alloy thin films according to claim 1, characterized in that, The reaction substrate includes one of the following: a silicon carbide substrate, a silicon substrate, and a silicon-germanium substrate.

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