N-type 4H-sic epitaxial growth control method and device, electronic equipment and storage medium

Abstract

The application provides an n-type 4H-SiC epitaxial growth control method and device, electronic equipment and storage medium, and relates to the technical field of semiconductor material epitaxial growth. The steps of the method comprise: in the epitaxial layer growth stage, methylhydrazine molecules in the methylhydrazine liquid stored in the doping source input part in advance are taken out and input into the reaction chamber by hydrogen, so that the methylhydrazine grows the epitaxial layer on the substrate as an n-type doping source. The method aims to solve the problems in the prior art that when nitrogen is used as an n-type doping source, the doping concentration consistency is poor, and when ammonia is used as an n-type doping source, the gas path system is complex, the equipment cost is high, the operation and maintenance are difficult, and the pollution risk may be introduced. The application uses methylhydrazine as a doping source to simplify the gas path and accurately control the doping concentration, and at the same time, the residual of nitrogen elements in the growth environment can be reduced, thereby effectively reducing the fluctuation of the nitrogen element concentration in the epitaxial layer, and stable doping is realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material epitaxial growth technology, and more specifically, to an n-type 4H-SiC epitaxial growth control method, apparatus, electronic device, and storage medium. Background Technology

[0002] The advantages of 4H-SiC in high frequency, high voltage, high temperature and high power make it an ideal material for power device manufacturing. 4H-SiC epitaxial growth plays a crucial role in the manufacturing of SiC power devices. The quality of epitaxy is affected by the substrate crystal quality and substrate pretreatment, and it also affects the final device performance.

[0003] Currently, the mainstream epitaxial growth method for 4H-SiC is chemical vapor deposition. Gaseous or liquid reactants containing the elements constituting the thin film are introduced into the reaction chamber under appropriate flow control. At a specific temperature, a series of decomposition and synthesis reactions are carried out to deposit a solid thin film on the substrate surface.

[0004] Existing 4H-SiC epitaxial growth technology generally uses nitrogen (N2) as the n-type doping source. Its disadvantage is that the doping concentration of n-type 4H-SiC is not consistent between different batches, which is not conducive to the growth of n-type 4H-SiC thin films with stable doping concentration.

[0005] Another 4H-SiC epitaxial growth technique uses ammonia (NH3) as an n-type dopant source. Its disadvantage is that NH3 needs to be mixed with hydrogen (H2) through two-stage dilution pipelines before it can enter the main pipeline and then the reaction chamber, which increases the complexity of the gas path.

[0006] There is currently no effective technical solution to the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a method, apparatus, electronic device, and storage medium for controlling n-type 4H-SiC epitaxial growth. This invention aims to solve the problems in existing 4H-SiC epitaxial growth technologies, such as poor doping concentration consistency when using nitrogen as the n-type doping source, and the complex gas path system, high equipment cost, difficult operation and maintenance, and potential pollution risks when using ammonia as the n-type doping source. Using methylhydrazine as the doping source simplifies the gas path and allows for precise control of the doping concentration. It also reduces nitrogen residue in the growth environment, effectively reducing fluctuations in nitrogen concentration within the epitaxial layer during silicon carbide epitaxial growth, thereby achieving stable doping.

[0008] In a first aspect, the present invention provides an n-type 4H-SiC epitaxial growth control method, which is applied to an epitaxial growth control system. The epitaxial growth control system includes a reaction chamber and a silicon source input section, a carbon source input section, a doping source input section, and a gas supply system connected to the reaction chamber.

[0009] The method for controlling the epitaxial growth of n-type 4H-SiC includes the following steps:

[0010] S1. After the substrate is placed in the reaction chamber, during the etching stage, the gas supply system is controlled to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber until the etching is completed;

[0011] S2. During the buffer layer growth stage, the silicon source input section, the carbon source input section, and the dopant source input section are controlled to input silicon source, carbon source, and n-type dopant source into the reaction chamber, respectively. The gas supply system controls the dopant source input section to use hydrogen gas to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input section and input them into the reaction chamber, so that methylhydrazine serves as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer growth is completed.

[0012] S3. During the epitaxial layer growth stage, the inputs of the silicon source input, the carbon source input, and the dopant source input are adjusted respectively. The gas supply system controls the dopant source input to use hydrogen to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input and input them into the reaction chamber, so that methylhydrazine serves as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer growth is completed.

[0013] The present invention provides an n-type 4H-SiC epitaxial growth control method that uses methylhydrazine as an n-type doping source. This method effectively solves the problems of poor nitrogen doping concentration consistency and complex ammonia doping gas path in the prior art, achieves stable doping of 4H-SiC epitaxial wafers, simplifies the gas path and precisely controls the doping concentration, while reducing nitrogen residue and reducing the fluctuation of nitrogen concentration in the epitaxial layer, thereby significantly improving the uniformity of device performance.

[0014] Furthermore, the specific steps in step S1 include:

[0015] S11. During the etching stage, after heating the substrate to 1650°C, hydrogen gas is introduced into the reaction chamber at a flow rate of 100 slm through the gas supply system, and the gas pressure in the reaction chamber is kept stable at 100 mbar until the etching is completed.

[0016] Furthermore, the silicon source input section is a first bubble bottle storing trichlorosilane liquid.

[0017] Furthermore, the carbon source input section is a gas device that stores ethylene gas.

[0018] Furthermore, the dopant source input is a second bubble bottle containing methylhydrazine liquid.

[0019] Furthermore, the specific steps in step S2 include:

[0020] S21. During the buffer layer growth stage, hydrogen gas is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 100 sccm and enter the reaction chamber, ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 40 sccm, and hydrogen gas is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 5 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at a stable 100 mbar until the buffer layer has completed its growth.

[0021] Furthermore, the specific steps in step S3 include:

[0022] S31. During the epitaxial layer growth stage, hydrogen gas is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 300 sccm and enter the reaction chamber, ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 150 sccm, and hydrogen gas is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 4 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at a stable 100 mbar until the buffer layer has completed growth.

[0023] Secondly, the present invention provides an n-type 4H-SiC epitaxial growth control device, which is applied to an epitaxial growth control system. The epitaxial growth control system includes a reaction chamber and a silicon source input section, a carbon source input section, a doping source input section, and a gas supply system connected to the reaction chamber.

[0024] The n-type 4H-SiC epitaxial growth control device includes:

[0025] The etching module is used to control the gas supply system to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber after the substrate is placed in the reaction chamber during the etching stage until the etching is completed.

[0026] A buffer layer growth module is used to control the silicon source input section, the carbon source input section, and the dopant source input section to respectively input silicon source, carbon source, and n-type dopant source into the reaction chamber during the buffer layer growth stage. The gas supply system controls the dopant source input section to use hydrogen to carry out methylhydrazine molecules pre-stored in the methylhydrazine liquid in the dopant source input section and input them into the reaction chamber, so that methylhydrazine serves as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer growth is completed.

[0027] An epitaxial layer growth module is used to adjust the inputs of the silicon source input section, the carbon source input section, and the dopant source input section respectively during the epitaxial layer growth stage. The gas supply system controls the dopant source input section to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input section through hydrogen gas and input them into the reaction chamber, so that methylhydrazine serves as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer growth is completed.

[0028] Thirdly, the present invention provides an electronic device including a processor and a memory, the memory storing computer-readable instructions, which, when executed by the processor, perform the steps of the n-type 4H-SiC epitaxial growth control method provided in the first aspect above.

[0029] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the steps of the n-type 4H-SiC epitaxial growth control method provided in the first aspect above.

[0030] As can be seen from the above, the n-type 4H-SiC epitaxial growth control method provided by this invention, by using methylhydrazine as the n-type dopant source, effectively solves the problem of poor doping concentration consistency among different batches of epitaxial wafers when using nitrogen as the dopant source in the prior art, and significantly improves the doping stability of n-type 4H-SiC thin films. Meanwhile, compared to using ammonia as the dopant source, which requires a complex two-stage dilution pipeline, the use of methylhydrazine in this application simplifies the gas path system, reduces equipment costs and operation and maintenance difficulties, and effectively reduces the risk of contamination. Furthermore, methylhydrazine as the dopant source enables precise control of the doping concentration and reduces nitrogen residue in the growth environment, thereby effectively reducing the fluctuation of nitrogen concentration in the epitaxial layer during silicon carbide epitaxial growth, achieving stable doping, and ultimately obtaining 4H-SiC power devices with uniform performance.

[0031] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0032] Figure 1 This is a flowchart of an n-type 4H-SiC epitaxial growth control method provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of an epitaxial growth control system in an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of a structure of an n-type 4H-SiC epitaxial growth control device provided in an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0036] Label Explanation:

[0037] 1. Reaction chamber; 2. Silicon source input section; 3. Carbon source input section; 4. Doping source input section; 5. Gas supply system; 100. Etching module; 200. Buffer layer growth module; 300. Epitaxial layer growth module; 13. Electronic equipment; 1301. Processor; 1302. Memory; 1303. Communication bus. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] Reference Appendix Figure 1 and attached Figure 2 This invention provides an n-type 4H-SiC epitaxial growth control method, which is applied to an epitaxial growth control system. The epitaxial growth control system includes a reaction chamber 1 and a silicon source input section 2, a carbon source input section 3, a doping source input section 4, and a gas supply system 5 connected to the reaction chamber 1.

[0041] The method for controlling the epitaxial growth of n-type 4H-SiC includes the following steps:

[0042] S1. After the substrate is placed in the reaction chamber (the reaction chamber is heated to 900°C, and then the substrate is placed into the transition chamber by a robotic arm, and then the substrate is sent into the reaction chamber by a transfer device in the transition chamber), during the etching stage, the gas supply system is controlled to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber until the etching is completed.

[0043] S2. During the buffer layer growth stage, the silicon source input section, carbon source input section, and dopant source input section are controlled to input silicon source, carbon source, and n-type dopant source into the reaction chamber, respectively. The gas supply system controls the dopant source input section to use hydrogen to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input section and input them into the reaction chamber, so that methylhydrazine can be used as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer growth is completed.

[0044] S3. During the epitaxial layer growth stage, the inputs of the silicon source input, carbon source input, and dopant source input are adjusted respectively. The gas supply system controls the dopant source input to use hydrogen to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input and input them into the reaction chamber, so that methylhydrazine can be used as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer growth is completed.

[0045] The innovation of this invention is mainly reflected in the use of a new n-type doping source: methylhydrazine, to achieve stable doping of 4H-SiC epitaxial wafers. Using methylhydrazine as the doping source simplifies the gas path and allows for precise control of the doping concentration. At the same time, it can reduce the residual nitrogen element in the growth environment, thereby effectively reducing the fluctuation of nitrogen element concentration in the epitaxial layer during the silicon carbide epitaxial growth process, and thus achieving stable doping.

[0046] The core of the n-type 4H-SiC epitaxial growth control method disclosed in this application lies in using methylhydrazine as an n-type dopant source to achieve stable doping of the 4H-SiC epitaxial wafer. The epitaxial growth control system is the hardware foundation for epitaxial growth, including a reaction chamber 1 to provide the controlled environment required for epitaxial growth; a silicon source input section 2, a carbon source input section 3, and a dopant source input section 4, which are responsible for introducing the silicon source, carbon source, and n-type dopant source into the reaction chamber 1, respectively; and a gas supply system 5, which controls the delivery of various gases and the gas pressure within the reaction chamber 1. The substrate is the base material for epitaxial growth, typically a silicon carbide (SiC) substrate. The etching stage aims to remove damage layers and contaminants from the substrate surface, providing a clean surface for subsequent epitaxial growth. The buffer layer growth stage involves first growing a thin buffer layer on the substrate to improve the interface quality between the epitaxial layer and the substrate and reduce defect density. The epitaxial layer growth stage involves growing an n-type 4H-SiC epitaxial layer with a specific thickness and doping concentration, which is a critical step in device fabrication. Methylhydrazine serves as an n-type dopant source. Its molecules are carried into reaction chamber 1 by hydrogen gas and decompose at high temperature, releasing n-type dopant atoms that are incorporated into the grown SiC lattice.

[0047] Specifically, the method for controlling the n-type 4H-SiC epitaxial growth of this application includes the following steps:

[0048] In step S1, after the substrate is placed in reaction chamber 1, the etching stage begins. Substrate placement can be achieved in various ways. For example, reaction chamber 1 can be heated to 900°C, and then the substrate can be placed into a transition chamber using a robotic arm, followed by the substrate being transported into reaction chamber 1 via a transfer device in the transition chamber. During the etching stage, the gas supply system 5 controls the input of hydrogen into reaction chamber 1 and maintains the gas pressure in reaction chamber 1 until etching is complete. Hydrogen, as the etching gas, can react with silicon or carbon atoms on the substrate surface at high temperatures to form volatile products, thereby removing the damaged layer and contaminants from the substrate surface. For example, the flow rate of hydrogen can be precisely controlled by a mass flow controller, and the gas pressure inside reaction chamber 1 can be maintained stably by a closed-loop control system consisting of a vacuum pump and a pressure sensor.

[0049] In step S2, the buffer layer growth stage begins. During this stage, silicon source input 2, carbon source input 3, and dopant source input 4 respectively input silicon source, carbon source, and n-type dopant source into reaction chamber 1. The silicon source can be a silicon-containing compound, such as trichlorosilane liquid, which can be stored and transported via a first bubbler. The carbon source can be a carbon-containing compound, such as ethylene gas, which can be stored and transported via a gas device. The n-type dopant source is the core innovation of this application, namely methylhydrazine liquid, which can be stored via a second bubbler. The gas supply system 5 controls the dopant source input 4 to use hydrogen gas to carry out methylhydrazine molecules pre-stored in the methylhydrazine liquid in the dopant source input 4 and input them into reaction chamber 1. The methylhydrazine molecules decompose within reaction chamber 1, releasing n-type dopant atoms, and a buffer layer grows on the substrate until the buffer layer growth is complete. For example, the input amount of methylhydrazine can be controlled by adjusting the flow rate of hydrogen gas through the second bubbler, thereby regulating the doping concentration of the buffer layer.

[0050] In step S3, the epitaxial layer growth stage begins. During this stage, the inputs to the silicon source input section 2, carbon source input section 3, and dopant source input section 4 are adjusted respectively. Similar to the buffer layer growth stage, the gas supply system 5 controls the dopant source input section 4 to use hydrogen gas to carry out methylhydrazine molecules pre-stored in the methylhydrazine liquid at the dopant source input section 4 and input them into the reaction chamber 1. Methylhydrazine, acting as an n-type dopant source, continues to grow the epitaxial layer on the substrate during the epitaxial layer growth stage until the epitaxial layer growth is complete. For example, the growth rate, thickness, and doping concentration of the epitaxial layer can be precisely controlled by adjusting the input flow rates of the silicon source, carbon source, and methylhydrazine, as well as the temperature and pressure of the reaction chamber 1.

[0051] The n-type 4H-SiC epitaxial growth control method of this application works by precisely controlling the gas composition, flow rate, temperature, and pressure within reaction chamber 1 to achieve stable growth and doping of the 4H-SiC epitaxial layer. First, during the etching stage, hydrogen gas is introduced into reaction chamber 1 to pretreat the substrate surface, removing defects and contaminants that may affect epitaxial quality, thus providing a clean and atomically flat surface for subsequent epitaxial growth. This step is crucial for ensuring good lattice matching between the epitaxial layer and the substrate and reducing interface defects.

[0052] Subsequently, during the buffer layer growth stage, the silicon source, carbon source, and n-type dopant source (methylhydrazine) are precisely introduced into reaction chamber 1. Specifically, the gas supply system 5 uses hydrogen to carry methylhydrazine molecules from the dopant source input section 4 and transport them to reaction chamber 1. The methylhydrazine molecules decompose at high temperature, and the n-type dopant atoms in the decomposition products are incorporated into the growing SiC lattice, forming a buffer layer. The growth of the buffer layer aims to alleviate the lattice mismatch between the substrate and the epitaxial layer, effectively suppressing the extension of defects into the epitaxial layer, thereby improving the crystal quality of the epitaxial layer.

[0053] Finally, during the epitaxial layer growth stage, the inputs of the silicon source, carbon source, and methylhydrazine were further adjusted to meet the growth requirements of the target epitaxial layer. Similar to the buffer layer growth, methylhydrazine continued to serve as the n-type dopant source, entering reaction chamber 1 under the influence of hydrogen gas and incorporating into the growing epitaxial layer. By precisely controlling the flow rates of the silicon source, carbon source, and methylhydrazine, as well as the temperature and pressure of reaction chamber 1, precise control over the growth rate, thickness, and doping concentration of the epitaxial layer could be achieved. Throughout the process, the use of methylhydrazine as the n-type dopant source simplified the gas path system, avoided the complexity associated with traditional nitrogen or ammonia doping, and effectively reduced nitrogen residue in the growth environment, thereby significantly reducing the fluctuation of nitrogen concentration within the epitaxial layer and ultimately achieving stable doping of the n-type 4H-SiC epitaxial wafer.

[0054] The core innovation of this application lies in using methylhydrazine as the n-type dopant source to achieve stable doping of 4H-SiC epitaxial wafers. Compared with existing methods using nitrogen or ammonia as the dopant source, this application has significant technical advantages. Traditionally, when using nitrogen doping, the doping efficiency of nitrogen in the SiC lattice is affected by various factors, resulting in poor consistency of doping concentration between different batches of epitaxial wafers, making it difficult to obtain n-type 4H-SiC thin films with stable doping concentrations. While ammonia doping offers some improvements, its complex two-stage dilution piping system not only increases equipment costs and operational maintenance difficulty but may also introduce additional contamination risks.

[0055] This application effectively solves the aforementioned problems by introducing methylhydrazine as an n-type dopant source. As an organic compound, methylhydrazine contains nitrogen atoms in its molecular structure and can provide the nitrogen element required for n-type doping after decomposition at high temperatures. More importantly, the introduction of methylhydrazine simplifies the gas path system, avoiding the complex dilution process required for traditional ammonia doping, thereby reducing equipment costs and operational maintenance difficulties. Furthermore, the use of methylhydrazine reduces nitrogen residue in the growth environment, effectively reducing fluctuations in nitrogen concentration within the epitaxial layer during silicon carbide epitaxial growth, ultimately achieving stable doping. This stable doping is of great significance for improving the performance uniformity and reliability of SiC power devices, representing an advancement unmatched by existing technologies.

[0056] In some embodiments, the specific steps in step S1 include:

[0057] S11. During the etching stage, after heating the substrate to 1650°C, hydrogen gas is introduced into the reaction chamber at a flow rate of 100 slm through the gas supply system, and the gas pressure in the reaction chamber is kept stable at 100 mbar until the etching is completed.

[0058] Specifically, the etching stage refers to the pretreatment of the substrate surface after it is placed in reaction chamber 1, before epitaxial growth, to remove surface oxide layers, damaged layers, or contaminants, providing a clean and smooth surface for subsequent epitaxial growth. Heating the substrate to 1650°C provides sufficient energy for hydrogen to effectively react with impurities or defects on the substrate surface, thus achieving etching. 1650°C is considered a preferred temperature, ensuring etching efficiency and substrate integrity. Hydrogen is supplied to reaction chamber 1 at a flow rate of 100 slm via gas supply system 5. As the etching gas, hydrogen reacts with the substrate surface at high temperature to remove surface defects. The 100 slm flow rate ensures sufficient hydrogen supply to maintain an effective etching rate. Simultaneously, the gas pressure in reaction chamber 1 is kept stable at 100 mbar to maintain a stable reaction environment during etching, avoiding adverse effects of pressure fluctuations on the epitaxial growth process and ensuring etching uniformity and repeatability. The etching process can be understood as ending when the substrate surface reaches the expected cleanliness and flatness.

[0059] The proposed solution heats the substrate to 1650°C and precisely controls the hydrogen flow rate to 100 slm and the gas pressure in reaction chamber 1 to be stabilized at 100 mbar. This allows hydrogen to react efficiently with the silicon carbide substrate surface under a high-temperature, low-pressure environment, removing surface oxides, damaged layers, and other contaminants. Specifically, at the high temperature of 1650°C, hydrogen molecules are endowed with higher activity, enabling them to more effectively decompose and combine with silicon or carbon atoms on the substrate surface to form volatile products (such as SiH4, CH4, etc.), thereby achieving etching of the substrate surface. The 100 slm hydrogen flow rate ensures an adequate supply of etchant, while the stable 100 mbar gas pressure helps maintain the uniformity and stability of the etching reaction, avoiding localized over-etching or under-etching. This precise control of process parameters effectively solves the problems of poor etching effect and unstable substrate surface quality caused by parameter uncertainties in traditional etching methods, providing an ideal starting surface for the subsequent growth of buffer layers and epitaxial layers.

[0060] The above technical solution precisely controls the temperature, hydrogen flow rate, and reaction chamber pressure during the etching stage, thereby significantly improving the uniformity and repeatability of the etching effect. Specifically, etching at 1650℃ more thoroughly removes defects and contaminants from the substrate surface while avoiding new damage to the substrate. A hydrogen flow rate of 100 slm and a stable gas pressure of 100 mbar ensure the stability and efficiency of the etching process, effectively reducing the surface roughness and defect density of the substrate after etching. Therefore, the solution presented in this application lays a solid foundation for the high-quality growth of subsequent buffer and epitaxial layers, contributing to the acquisition of n-type 4H-SiC epitaxial wafers with superior electrical properties and lower defect density.

[0061] In some embodiments, the silicon source input 2 is a first bubble bottle storing trichlorosilane (TCS) liquid; the carbon source input 3 is a gas device storing ethylene (C2H2) gas; and the dopant source input is a second bubble bottle storing methylhydrazine (CH6N2) liquid.

[0062] The silicon source input section 2 employs a first bubble bottle storing liquid trichlorosilane. Specifically, liquid trichlorosilane is used as a silicon source precursor, and its vapor is introduced into the reaction chamber 1 via bubbling. Trichlorosilane is a commonly used silicon source with high purity and stability, and the bubble bottle design facilitates precise control of its vapor flow rate via a carrier gas (e.g., hydrogen), thereby achieving a stable input of the silicon source.

[0063] The carbon source input unit 3 employs a gas device storing ethylene gas. Specifically, it uses gaseous ethylene as a carbon source precursor, and its flow rate is directly controlled and input into the reaction chamber 1 via a gas flow controller or similar device. Ethylene, as a common carbon source, is readily metered and transported in its gaseous form through a standard gas control system, ensuring the accuracy of the carbon source input.

[0064] The dopant source input unit 4 employs a second bubble bottle storing liquid methylhydrazine. Specifically, liquid methylhydrazine is used as an n-type dopant source, and its vapor is introduced into the reaction chamber 1 via bubbling. Methylhydrazine, as a novel n-type dopant source, is transported in liquid form via a bubble bottle, which simplifies gas path design and enables precise control of the doping concentration. It also helps reduce the nitrogen residue problems that may arise from traditional nitrogen dopant sources.

[0065] The scheme of this application specifically configures the silicon source input section 2, the carbon source input section 3, and the dopant source input section 4 as a first bubbler bottle, a gas device, and a second bubbler bottle, enabling various precursors to be precisely introduced into the reaction chamber 1 in their suitable physical forms. Specifically, for the liquid precursors trichlorosilane and methylhydrazine, the bubbler bottle design allows the carrier gas to pass through the liquid, saturating and carrying out the precursor molecules, and its flow rate can be finely adjusted by the carrier gas flow rate and the bubbler temperature. For the gaseous precursor ethylene, the gas device can achieve high-precision flow control directly through a flow controller. This ensures that the input flow rates of the silicon source, carbon source, and n-type dopant source are stable and controllable during the n-type 4H-SiC epitaxial growth process, providing a material basis for the stable growth of the subsequent buffer layer and epitaxial layer.

[0066] The above technical solution clarifies the specific input forms of the silicon source, carbon source, and n-type dopant source, resulting in higher operability and stability of the epitaxial growth control system in actual operation. Specifically, using a bubble bottle to transport the liquid precursor (trichlorosilane and methylhydrazine) and a gas device to transport the gaseous precursor (ethylene) effectively ensures precise control and stability of the input flow rates of each component, thereby contributing to the compositional uniformity during the epitaxial layer growth process and improving the quality and repeatability of the n-type 4H-SiC epitaxial wafer. This specific configuration provides a reliable hardware foundation for achieving the stable doping target proposed in this application.

[0067] In some embodiments, the specific steps in step S2 include:

[0068] S21. During the buffer layer growth stage, hydrogen is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 100 sccm and enter the reaction chamber, and ethylene is controlled by the gas device to enter the reaction chamber at a flow rate of 40 sccm. Hydrogen is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 5 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at 100 mbar until the buffer layer growth is complete.

[0069] Specifically, during the buffer layer growth stage, to achieve precise material deposition and doping control, the trichlorosilane liquid in the silicon source input section 2 (i.e., the first bubble bottle) is carried out by hydrogen gas controlled by the gas supply system 5 at a flow rate of 100 sccm and fed into the reaction chamber 1. Simultaneously, ethylene gas from the carbon source input section 3 (i.e., the gas device) is directly introduced into the reaction chamber 1 at a flow rate of 40 sccm. Furthermore, the methylhydrazine liquid in the doping source input section 4 (i.e., the second bubble bottle) is carried by hydrogen gas controlled by the gas supply system 5 at a flow rate of 5 sccm and fed into the reaction chamber 1. Throughout the buffer layer growth process, the gas pressure within the reaction chamber 1 is precisely stabilized at 100 mbar. These parameter settings aim to ensure stable growth of the buffer layer and provide a high-quality substrate surface for subsequent epitaxial layer growth.

[0070] This application's solution effectively solves the growth instability problem caused by parameter uncertainty in traditional methods by precisely quantifying and controlling various process parameters during the buffer layer growth stage. Specifically, the flow rate of hydrogen through the first bubbler is set to 100 sccm, ensuring a stable and appropriate supply of the silicon source (trichlorosilane), avoiding the impact of excessive or insufficient silicon source on the quality of the buffer layer. Simultaneously, the ethylene flow rate is controlled at 40 sccm, achieving an optimal ratio between the carbon source and silicon source, which is beneficial for forming a high-quality silicon carbide crystal structure. Furthermore, the hydrogen flow rate through the second bubbler is precisely controlled at 5 sccm, ensuring stable and uniform doping of the n-type dopant source (methylhydrazine), thereby achieving precise control of the buffer layer doping concentration. Based on this, the gas pressure in reaction chamber 1 is stabilized at 100 mbar, providing a stable environment for the gas-phase reaction, optimizing the adsorption and reaction process of reactants on the substrate surface, and further promoting uniform growth and defect suppression of the buffer layer. It is precisely because of these precise parameter controls that the buffer layer can grow at the expected rate and quality.

[0071] The above technical solution precisely quantifies and controls key parameters during the buffer layer growth stage, significantly improving the stability and repeatability of buffer layer growth. Specifically, the precisely controlled input flow rates of the silicon source, carbon source, and dopant source, as well as the stable gas pressure in reaction chamber 1, effectively ensure uniform growth of the buffer layer on the substrate, achieving the expected thickness and crystal quality. This significantly reduces the defect density within the buffer layer, improves its surface flatness, and provides a more ideal starting interface for subsequent epitaxial layer growth, ultimately contributing to the acquisition of n-type 4H-SiC epitaxial wafers with excellent electrical performance and high reliability.

[0072] In some embodiments, the specific steps in step S3 include:

[0073] S31. During the epitaxial layer growth stage, hydrogen gas is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 300 sccm and enter the reaction chamber, and ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 150 sccm. Hydrogen gas is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 4 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at 100 mbar until the buffer layer has completed growth.

[0074] Specifically, during the epitaxial layer growth stage, hydrogen gas is supplied at a flow rate of 300 sccm through the first bubbler flask and into reaction chamber 1 via gas supply system 5. This aims to precisely control the delivery of the silicon source, trichlorosilane, to ensure a sufficient supply of silicon and a stable growth rate in the epitaxial layer. Simultaneously, ethylene gas is supplied at a flow rate of 150 sccm through a gas device into reaction chamber 1 to provide an appropriate amount of carbon source to form the SiC crystal structure with the silicon source and maintain a suitable carbon-silicon ratio to suppress defect formation. Furthermore, hydrogen gas is supplied at a flow rate of 4 sccm through the second bubbler flask and into reaction chamber 1 to introduce methylhydrazine molecules into reaction chamber 1 as an n-type dopant source, achieving precise control of the doping concentration in the epitaxial layer. During this process, the gas pressure in reaction chamber 1 is stabilized at 100 mbar, which helps maintain a uniform distribution of the reaction gas and stable reaction kinetics within reaction chamber 1, thereby promoting the growth of a high-quality epitaxial layer. The entire process continues until the epitaxial layer growth is complete.

[0075] This application's solution effectively solves problems such as growth rate fluctuations, uneven doping concentration, and film quality degradation that may occur during epitaxial layer growth by precisely setting the input flow rates of the silicon source, carbon source, and n-type dopant source, as well as the gas pressure in reaction chamber 1. Specifically, a hydrogen flow rate of 300 sccm passing through the first bubbler ensures a stable supply of the silicon source; a carbon source flow rate of 150 sccm ensures the precise introduction of the carbon source. The two work synergistically to maintain an ideal carbon-silicon ratio, thereby promoting the formation of high-quality 4H-SiC crystals. Simultaneously, a hydrogen flow rate of 4 sccm passing through the second bubbler allows the methylhydrazine dopant source to enter reaction chamber 1 in a controlled manner, achieving precise control of the n-type doping concentration in the epitaxial layer and avoiding the doping inhomogeneities that may arise from traditional doping sources. Furthermore, stabilizing the gas pressure in reaction chamber 1 at 100 mbar helps optimize the diffusion and adsorption processes of the reaction gases, further improving the uniformity and crystal quality of the epitaxial layer. It is precisely because of these precise parameter settings that the epitaxial layer can grow at a stable rate, with uniform doping concentration and excellent crystal quality.

[0076] Through the above technical solutions, this application can significantly improve the stability and controllability of n-type 4H-SiC epitaxial layer growth. Precise flow control and gas pressure maintenance make the growth rate of the epitaxial layer more stable, effectively avoiding film thickness unevenness caused by parameter fluctuations. In addition, the precise introduction of the methylhydrazine dopant source ensures a uniform distribution of n-type doping concentration inside the epitaxial layer, thereby reducing the inconsistency of device performance. This refined parameter control ultimately helps to obtain n-type 4H-SiC epitaxial wafers with higher crystal quality, lower defect density, and better electrical performance, providing a solid foundation for the manufacture of high-performance power electronic devices.

[0077] Please refer to Figure 3 , Figure 3 This invention provides an n-type 4H-SiC epitaxial growth control device in some embodiments, applied to an epitaxial growth control system. The epitaxial growth control system includes a reaction chamber 1 and a silicon source input section 2, a carbon source input section 3, a doping source input section 4, and a gas supply system 5, all connected to the reaction chamber 1. This n-type 4H-SiC epitaxial growth control device is integrated into a back-end control device in the form of a computer program, including:

[0078] The etching module 100 is used to control the gas supply system to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber after the substrate is placed in the reaction chamber during the etching stage until the etching is completed.

[0079] The buffer layer growth module 200 is used to control the silicon source input section, carbon source input section and dopant source input section to input silicon source, carbon source and n-type dopant source into the reaction chamber respectively during the buffer layer growth stage. The gas supply system controls the dopant source input section to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input section through hydrogen and input them into the reaction chamber, so that methylhydrazine can be used as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer growth is completed.

[0080] The epitaxial layer growth module 300 is used to adjust the input of the silicon source input section, carbon source input section and dopant source input section respectively during the epitaxial layer growth stage. The gas supply system controls the dopant source input section to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the dopant source input section through hydrogen gas and input them into the reaction chamber, so that methylhydrazine can be used as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer growth is completed.

[0081] In some embodiments, after the substrate is placed into the reaction chamber, the etching module 100, during the etching stage, controls the gas supply system to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber until the etching is completed.

[0082] S11. During the etching stage, after heating the substrate to 1650°C, hydrogen gas is introduced into the reaction chamber at a flow rate of 100 slm through the gas supply system, and the gas pressure in the reaction chamber is kept stable at 100 mbar until the etching is completed.

[0083] In some embodiments, the buffer layer growth module 200 is used to control the silicon source input section, carbon source input section, and dopant source input section to respectively input silicon source, carbon source, and n-type dopant source into the reaction chamber during the buffer layer growth stage. The gas supply system controls the dopant source input section to use hydrogen gas to carry out methylhydrazine molecules pre-stored in the methylhydrazine liquid at the dopant source input section and input them into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow a buffer layer on the substrate. This process continues until the buffer layer growth is complete.

[0084] S21. During the buffer layer growth stage, hydrogen is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 100 sccm and enter the reaction chamber, and ethylene is controlled by the gas device to enter the reaction chamber at a flow rate of 40 sccm. Hydrogen is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 5 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at 100 mbar until the buffer layer growth is complete.

[0085] In some embodiments, the epitaxial layer growth module 300 is used to adjust the inputs of the silicon source input, carbon source input, and dopant source input respectively during the epitaxial layer growth stage. The gas supply system controls the dopant source input to use hydrogen gas to carry out methylhydrazine molecules pre-stored in the methylhydrazine liquid at the dopant source input and input them into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow an epitaxial layer on the substrate. This process continues until the epitaxial layer growth is complete.

[0086] S31. During the epitaxial layer growth stage, hydrogen gas is controlled by the gas supply system to pass through the first bubbling bottle at a flow rate of 300 sccm and enter the reaction chamber, and ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 150 sccm. Hydrogen gas is controlled by the gas supply system to pass through the second bubbling bottle at a flow rate of 4 sccm and enter the reaction chamber, while maintaining the gas pressure in the reaction chamber at 100 mbar until the buffer layer has completed growth.

[0087] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The present invention provides an electronic device 13, including: a processor 1301 and a memory 1302. The processor 1301 and the memory 1302 are interconnected and communicate with each other via a communication bus 1303 and / or other forms of connection mechanism (not shown). The memory 1302 stores computer-readable instructions executable by the processor 1301. When the electronic device is running, the processor 1301 executes the computer-readable instructions to perform the method in any optional implementation of the above embodiments, to achieve the following functions: after the substrate is placed in the reaction chamber, during the etching stage, the gas supply system is controlled to input hydrogen into the reaction chamber and maintain the gas pressure in the reaction chamber until etching is completed; in the buffer layer... During the long-term stage, the silicon source input section, carbon source input section, and dopant source input section are controlled to input silicon source, carbon source, and n-type dopant source into the reaction chamber, respectively. The gas supply system controls the dopant source input section to use hydrogen gas to carry out methylhydrazine molecules from the methylhydrazine liquid pre-stored in the dopant source input section and input them into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer growth is complete. During the epitaxial layer growth stage, the inputs of the silicon source input section, carbon source input section, and dopant source input section are adjusted, and the gas supply system controls the dopant source input section to use hydrogen gas to carry out methylhydrazine molecules from the methylhydrazine liquid pre-stored in the dopant source input section and input them into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer growth is complete.

[0088] This invention provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it performs the method in any optional implementation of the above embodiments to achieve the following functions: after the substrate is placed in the reaction chamber, during the etching stage, the gas supply system is controlled to input hydrogen gas into the reaction chamber and maintain the gas pressure in the reaction chamber until etching is completed; during the buffer layer growth stage, the silicon source input section, carbon source input section, and dopant source input section are controlled to input silicon source, carbon source, and n-type dopant source into the reaction chamber, respectively, wherein the gas supply system controls the dopant source input section to use hydrogen gas... Methylhydrazine molecules, pre-stored in the methylhydrazine liquid at the dopant source input, are carried out and introduced into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow a buffer layer on the substrate until the buffer layer is fully grown. During the epitaxial layer growth stage, the inputs of the silicon source input, carbon source input, and dopant source input are adjusted respectively. The gas supply system controls the dopant source input to use hydrogen gas to carry out the methylhydrazine molecules, pre-stored in the methylhydrazine liquid at the dopant source input, and introduce them into the reaction chamber, so that methylhydrazine acts as an n-type dopant source to grow an epitaxial layer on the substrate until the epitaxial layer is fully grown.

[0089] The computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0090] In the embodiments provided by this invention, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0091] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0092] Furthermore, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0093] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0094] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An n-type 4H-SiC epitaxial growth control method applied to an epitaxial growth control system, characterized by, The epitaxial growth control system comprises a reaction chamber (1) and a silicon source input part (2), a carbon source input part (3), a doping source input part (4) and a gas supply system (5) in communication with the reaction chamber (1); the silicon source input part (2) is a first bubbling bottle storing liquid trichlorosilane; the carbon source input part (3) is a gas device storing ethylene gas; the doping source input part (4) is a second bubbling bottle storing liquid methylhydrazine; The n-type 4H-SiC epitaxial growth control method comprises the following steps: S1. After the substrate is placed in the reaction chamber, in the etching stage, the gas supply system is controlled to input hydrogen into the reaction chamber and maintain the gas pressure of the reaction chamber until etching is completed. S2. In the buffer layer growth stage, the silicon source input part, the carbon source input part and the doping source input part are controlled to respectively input silicon source, carbon source and n-type doping source into the reaction chamber, wherein the gas supply system controls the doping source input part to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part by hydrogen and input into the reaction chamber, so that methylhydrazine grows as an n-type doping source on the substrate to grow a buffer layer, until the buffer layer is completed; the specific steps include: S21. In the buffer layer growth stage, the gas supply system controls hydrogen to flow through the first bubbling bottle at a flow rate of 100 sccm and into the reaction chamber, the gas device controls ethylene to flow into the reaction chamber at a flow rate of 40 sccm, and the gas supply system controls hydrogen to flow through the second bubbling bottle at a flow rate of 5 sccm and into the reaction chamber, and the gas pressure of the reaction chamber is maintained at 100 mbar until the buffer layer is completed. S3. In the epitaxial layer growth stage, the silicon source input part, the carbon source input part and the doping source input part are adjusted respectively, wherein the gas supply system controls the doping source input part to carry out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part by hydrogen and input into the reaction chamber, so that methylhydrazine grows as an n-type doping source on the substrate to grow an epitaxial layer, until the epitaxial layer is completed; the specific steps include: S31. In the epitaxial layer growth stage, the gas supply system controls hydrogen to flow through the first bubbling bottle at a flow rate of 300 sccm and into the reaction chamber, the gas device controls ethylene to flow into the reaction chamber at a flow rate of 150 sccm, and the gas supply system controls hydrogen to flow through the second bubbling bottle at a flow rate of 4 sccm and into the reaction chamber, and the gas pressure of the reaction chamber is maintained at 100 mbar until the epitaxial layer is completed.

2. The n-type 4H-SiC epitaxial growth control method according to claim 1, characterized by, The specific steps in step S1 include: S11. In the etching stage, after the substrate is heated to 1650℃, the gas supply system controls hydrogen to flow into the reaction chamber at a flow rate of 100 slm and maintains the gas pressure of the reaction chamber at 100 mbar until etching is completed.

3. An n-type 4H-SiC epitaxial growth control device, applied to an epitaxial growth control system, characterized in that, The epitaxial growth control system comprises a reaction chamber (1) and a silicon source input part (2), a carbon source input part (3), a doping source input part (4) and a gas supply system (5) in communication with the reaction chamber (1); the silicon source input part (2) is a first bubbling bottle storing liquid trichlorosilane; the carbon source input part (3) is a gas device storing ethylene gas; the doping source input part (4) is a second bubbling bottle storing liquid methylhydrazine; The n-type 4H-SiC epitaxial growth control device comprises: An etching module for, after the substrate is put into the reaction chamber, controlling the gas supply system to input hydrogen into the reaction chamber and keeping the gas pressure of the reaction chamber until etching is completed in the etching stage; A buffer layer growth module for, in the buffer layer growth stage, controlling the silicon source input part, the carbon source input part and the doping source input part to input silicon source, carbon source and n-type doping source into the reaction chamber respectively, wherein the gas supply system controls the doping source input part to take out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part through hydrogen and input into the reaction chamber, so that methylhydrazine grows as an n-type doping source on the substrate to grow a buffer layer, until the buffer layer is completed; the specific steps include: S21. In the buffer layer growth stage, the hydrogen gas is controlled by the gas supply system to flow through the first bubbling bottle at a flow rate of 100 sccm and enter the reaction chamber, the ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 40 sccm, the hydrogen gas is controlled by the gas supply system to flow through the second bubbling bottle at a flow rate of 5 sccm and enter the reaction chamber, and the gas pressure of the reaction chamber is kept stable at 100 mbar, until the buffer layer is completed; An epitaxial layer growth module for, in the epitaxial layer growth stage, adjusting the input of the silicon source input part, the carbon source input part and the doping source input part respectively, wherein the gas supply system controls the doping source input part to take out methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part through hydrogen and input into the reaction chamber, so that methylhydrazine grows as an n-type doping source on the substrate to grow an epitaxial layer, until the epitaxial layer is completed; the specific steps include: S31. In the epitaxial layer growth stage, the hydrogen gas is controlled by the gas supply system to flow through the first bubbling bottle at a flow rate of 300 sccm and enter the reaction chamber, the ethylene gas is controlled by the gas device to enter the reaction chamber at a flow rate of 150 sccm, the hydrogen gas is controlled by the gas supply system to flow through the second bubbling bottle at a flow rate of 4 sccm and enter the reaction chamber, and the gas pressure of the reaction chamber is kept stable at 100 mbar, until the epitaxial layer is completed.

4. An electronic device, comprising: The n-type 4H-SiC epitaxial growth control device comprises: a processor and a memory, the memory storing computer readable instructions, when the computer readable instructions are executed by the processor, the steps in the n-type 4H-SiC epitaxial growth control method of any one of claims 1-2 are executed.

5. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by a processor, performs the steps of the n-type 4H-SiC epitaxial growth control method of any of claims 1-2.

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