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

Abstract

The invention provides an n-type 4H-SiC epitaxial growth control method and device, electronic equipment and a storage medium, and relates to the technical field of semiconductor material epitaxial growth. The method comprises the following steps: in an epitaxial layer growth stage, taking out methylhydrazine molecules in methylhydrazine liquid pre-stored in a doping source input part through hydrogen, and inputting the methylhydrazine molecules into a reaction chamber, so that methylhydrazine is used as an n-type doping source to grow an epitaxial layer on a substrate. The method aims at solving the problems that in the prior art, when nitrogen is adopted as an n-type doping source, the doping concentration consistency is poor, and when ammonia is adopted as the n-type doping source, a gas path system is complex, the equipment cost is high, the operation and maintenance difficulty is large, and the pollution risk is possibly introduced. According to the invention, methylhydrazine is adopted as the doping source, so that a gas path can be simplified, the doping concentration can be accurately regulated and controlled, and meanwhile, the residual nitrogen element in the growth environment can be reduced, thereby effectively reducing the fluctuation of the nitrogen element concentration in the epitaxial layer, and further realizing stable doping.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of epitaxial growth of semiconductor materials, in particular to an n-type 4H-SiC epitaxial growth control method and device, electronic equipment and storage medium. BACKGROUND

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

[0003] The current mainstream epitaxial growth method of 4H-SiC is chemical vapor deposition. Gaseous or liquid reactants containing film elements are introduced into the reaction chamber under suitable flow control, and a solid film is deposited on the substrate surface through a series of decomposition and synthesis reactions at a specific temperature.

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

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

[0006] There is currently no effective technical solution to the above problems. SUMMARY

[0007] The present application aims to provide an n-type 4H-SiC epitaxial growth control method and device, electronic equipment and storage medium, which solves the problems of poor doping concentration consistency when using nitrogen as an n-type doping source, and complex gas path system, high equipment cost, difficult operation and maintenance, and possible pollution risk when using ammonia as an n-type doping source in the existing 4H-SiC epitaxial growth technology. Using methylhydrazine as a doping source can simplify the gas path and precisely control the doping concentration, while reducing the residual nitrogen element in the growth environment, thereby effectively reducing the fluctuation of nitrogen element concentration in the epitaxial layer during the epitaxial growth of silicon carbide, and achieving stable doping.

[0008] In a first aspect, the present application provides an n-type 4H-SiC epitaxial growth control method, applied to an epitaxial growth control system, wherein the epitaxial growth control system comprises a reaction chamber, a silicon source input part, a carbon source input part, a doping source input part and a gas supply system in communication with the reaction chamber. The n-type 4H-SiC epitaxial growth control method comprises the following steps: S1. After placing the substrate into the reaction chamber, in the etching stage, the gas supply system controls the input of hydrogen into the reaction chamber and maintains the gas pressure of the reaction chamber until the 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 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 carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow a buffer layer, until the buffer layer is completed. S3. In the epitaxial layer growth stage, the input of the silicon source input part, the carbon source input part and the doping source input part is adjusted respectively, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow an epitaxial layer, until the epitaxial layer is completed.

[0009] The n-type 4H-SiC epitaxial growth control method provided by the present application uses methylhydrazine as an n-type doping source, effectively solves the problems of poor consistency of nitrogen doping concentration and complex ammonia doping gas path in the prior art, realizes stable doping of 4H-SiC epitaxial wafer, simplifies the gas path and accurately controls the doping concentration, reduces the residual nitrogen element, reduces the fluctuation of nitrogen element concentration in the epitaxial layer, and significantly improves the uniformity of device performance.

[0010] Further, the specific steps in step S1 include: S11. In the etching stage, after heating the substrate to 1650℃, the gas supply system controls the 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 the etching is completed.

[0011] Further, the silicon source input part is a first bubbling bottle storing a trichlorosilane liquid.

[0012] Further, the carbon source input part is a gas device storing ethylene gas.

[0013] Further, the doping source input part is a second bubbling bottle storing a methylhydrazine liquid.

[0014] Further, the specific steps in step S2 include: S21. In the buffer layer growth stage, the hydrogen gas is controlled by the gas supply system to flow at 100 sccm through the first bubbler and into the reaction chamber, and the ethylene is controlled by the gas device to flow at 40 sccm into the reaction chamber, and the hydrogen gas is controlled by the gas supply system to flow at 5 sccm through the second bubbler and into the reaction chamber, and the gas pressure in the reaction chamber is kept stable at 100 mbar until the buffer layer is completed.

[0015] Further, the specific steps in step S3 include: S31. In the epitaxial layer growth stage, the hydrogen gas is controlled by the gas supply system to flow at 300 sccm through the first bubbler and into the reaction chamber, and the ethylene is controlled by the gas device to flow at 150 sccm into the reaction chamber, and the hydrogen gas is controlled by the gas supply system to flow at 4 sccm through the second bubbler and into the reaction chamber, and the gas pressure in the reaction chamber is kept stable at 100 mbar until the buffer layer is completed.

[0016] In a second aspect, the present application provides an n-type 4H-SiC epitaxial growth control device applied to an epitaxial growth control system, wherein the epitaxial growth control system comprises a reaction chamber, a silicon source input part, a carbon source input part, a doping source input part and a gas supply system in communication with the reaction chamber. 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 gas into the reaction chamber and keeping the gas pressure in the reaction chamber until the 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 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 take out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen gas and input them into the reaction chamber, so that the methylhydrazine grows a buffer layer on the substrate as an n-type doping source until the buffer layer is completed. An epitaxial layer growth module for, in the epitaxial layer growth stage, respectively adjusting the input of the silicon source input part, the carbon source input part and the doping source input part, wherein the gas supply system controls the doping source input part to take out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen gas and input them into the reaction chamber, so that the methylhydrazine grows an epitaxial layer on the substrate as an n-type doping source until the epitaxial layer is completed.

[0017] In a third aspect, the present application provides an electronic device comprising a processor and a memory, wherein the memory stores computer readable instructions which, when executed by the processor, implement the steps of the n-type 4H-SiC epitaxial growth control method according to the first aspect.

[0018] In a fourth aspect, the present application provides a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the n-type 4H-SiC epitaxial growth control method according to the first aspect.

[0019] As can be seen from the above, the n-type 4H-SiC epitaxial growth control method provided by the present application effectively solves the problem of poor consistency of doping concentration of different batches of epitaxial wafers when nitrogen is used as a doping source in the prior art, and significantly improves the doping stability of the n-type 4H-SiC thin film. At the same time, compared with the complex two-stage dilution pipeline required when ammonia is used as a doping source, the use of methylhydrazine in the present application can simplify the gas path system, reduce the equipment cost and operation and maintenance difficulty, and effectively reduce the pollution risk. In addition, as a doping source, methylhydrazine can realize precise regulation and control of the doping concentration and reduce the residual nitrogen element in the growth environment, thereby effectively reducing the fluctuation of the nitrogen element concentration in the epitaxial layer during the epitaxial growth of silicon carbide, and realizing stable doping, and finally obtaining a 4H-SiC power device with uniform performance.

[0020] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application according to the embodiments. The objects and other advantages of the present application can be achieved and obtained by the structure particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A flow chart of the n-type 4H-SiC epitaxial growth control method provided by the embodiments of the present application.

[0022] Figure 2 A structural schematic diagram of the epitaxial growth control system in the embodiments of the present application.

[0023] Figure 3 A structural schematic diagram of the n-type 4H-SiC epitaxial growth control device provided by the embodiments of the present application.

[0024] Figure 4 A structural schematic diagram of the electronic device provided by the embodiments of the present application.

[0025] REFERENCE NUMERALS: 1, reaction chamber; 2, silicon source input part; 3, carbon source input part; 4, doping source input part; 5, gas supply system; 100, etching module; 200, buffer layer growth module; 300, epitaxial layer growth module; 13, electronic device; 1301, processor; 1302, memory; 1303, communication bus. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0028] Reference is made to the accompanying drawings of Figure 1 and the accompanying drawings of Figure 2 , the present application provides an n-type 4H-SiC epitaxial growth control method applied to an epitaxial growth control system, the epitaxial growth control system comprising 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 n-type 4H-SiC epitaxial growth control method comprises the following steps: S1. After placing the substrate into the reaction chamber (heating the reaction chamber to 900℃, then placing the substrate into the transition cavity through the mechanical arm, and then sending the substrate into the reaction chamber through the conveying device of the transition cavity), 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 the 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 the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part through hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow a buffer layer, until the buffer layer is completed; S3. In the epitaxial layer growth stage, the input of the silicon source input part, the carbon source input part and the doping source input part is adjusted respectively, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow an epitaxial layer, until the epitaxial layer is completed; The innovation of the present application mainly lies in the use of a new n-type doping source: methylhydrazine, which realizes stable doping of 4H-SiC epitaxial wafer. Using methylhydrazine as a doping source can simplify the gas path and accurately control the doping concentration, while reducing the residual nitrogen element in the growth environment, thereby effectively reducing the fluctuation of the nitrogen element concentration in the epitaxial layer during the silicon carbide epitaxial growth process, and realizing stable doping.

[0029] The n-type 4H-SiC epitaxial growth control method disclosed in the present application is characterized by using methylhydrazine as an n-type doping source to realize stable doping of 4H-SiC epitaxial wafer. The epitaxial growth control system is the hardware basis for epitaxial growth, which includes a reaction chamber 1 for providing a controlled environment required for epitaxial growth; a silicon source input part 2, a carbon source input part 3 and a doping source input part 4 respectively responsible for introducing silicon source, carbon source and n-type doping source into the reaction chamber 1; and a gas supply system 5 for controlling the delivery of various gases and the gas pressure in the reaction chamber 1. The substrate is the base material for epitaxial growth, usually a silicon carbide (SiC) substrate. The etching stage aims to remove the damage layer and contaminants on the surface of the substrate to provide a clean surface for subsequent epitaxial growth. The buffer layer growth stage is to grow a thin buffer layer on the substrate to improve the interface quality between the epitaxial layer and the substrate and reduce the defect density. The epitaxial layer growth stage is to grow an n-type 4H-SiC epitaxial layer with a certain thickness and doping concentration, which is a key step in device manufacturing. Methylhydrazine as an n-type doping source, its molecules enter the reaction chamber 1 under the carrying of hydrogen, and decompose at high temperature to release n-type doping atoms and incorporate into the growing SiC lattice.

[0030] Specifically, the n-type 4H-SiC epitaxial growth control method of the present application comprises the following steps: In step S1, after placing the substrate into the reaction chamber 1, the etching phase is entered. The placement of the substrate can be achieved in various ways, for example, the reaction chamber 1 can be heated to 900°C, and then the substrate is placed into the transition cavity through the mechanical arm, and then the substrate is sent into the reaction chamber 1 through the conveying device of the transition cavity. In the etching phase, the gas supply system 5 controls the input of hydrogen into the reaction chamber 1 and maintains the gas pressure of the reaction chamber 1 until the etching is completed. Hydrogen as an etching gas can react with silicon atoms or carbon atoms on the surface of the substrate at high temperature to form volatile products, thereby removing the damage layer and contaminants on the surface of the substrate. For example, the flow rate of hydrogen can be accurately controlled by a mass flow controller, and the gas pressure in the reaction chamber 1 can be maintained stable by a closed-loop control system composed of a vacuum pump and a pressure sensor.

[0031] In step S2, the buffer layer growth phase is entered. In this phase, the silicon source input part 2, the carbon source input part 3 and the doping source input part 4 respectively input the silicon source, the carbon source and the n-type doping source into the reaction chamber 1. The silicon source can be a compound containing silicon elements, such as trichlorosilane liquid, which can be stored and delivered by the first bubble bottle. The carbon source can be a compound containing carbon elements, such as ethylene gas, which can be stored and delivered by a gas device. The n-type doping source is the core innovation point of the present application, i.e. methylhydrazine liquid, which can be stored by the second bubble bottle. The gas supply system 5 controls the doping source input part 4 to bring out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part 4 by hydrogen and input them into the reaction chamber 1. The methylhydrazine molecules decompose in the reaction chamber 1, release n-type doping atoms, and grow a buffer layer on the substrate until the buffer layer is completed. For example, the input amount of methylhydrazine can be controlled by adjusting the flow rate of hydrogen through the second bubble bottle, so as to regulate the doping concentration of the buffer layer.

[0032] In step S3, the epitaxial layer growth phase is entered. In this phase, the input of the silicon source input part 2, the carbon source input part 3 and the doping source input part 4 is adjusted respectively. Similar to the buffer layer growth phase, the gas supply system 5 controls the doping source input part 4 to bring out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part 4 by hydrogen and input them into the reaction chamber 1. Methylhydrazine as an n-type doping source continues to grow an epitaxial layer on the substrate in the epitaxial layer growth phase until the epitaxial layer is completed. For example, the growth rate, thickness and doping concentration of the epitaxial layer can be accurately controlled by adjusting the input flow rates of silicon source, carbon source and methylhydrazine, as well as the temperature and gas pressure of the reaction chamber 1.

[0033] The n-type 4H-SiC epitaxial growth control method of the present application is based on the principle of precisely controlling the gas composition, flow rate, temperature and gas pressure in the reaction chamber 1 to achieve stable growth and doping of the 4H-SiC epitaxial layer. First, during the etching stage, hydrogen is introduced into the reaction chamber 1 to pre-treat the substrate surface, removing defects and contaminants that may affect the quality of the epitaxial layer and 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.

[0034] Subsequently, during the buffer layer growth stage, silicon source, carbon source and n-type doping source (methylhydrazine) are precisely introduced into the reaction chamber 1. The gas supply system 5 carries the methylhydrazine molecules from the doping source input 4 into the reaction chamber 1 by hydrogen. The methylhydrazine molecules decompose at high temperature, and the n-type doping atoms in the decomposition products are incorporated into the growing SiC lattice to form a buffer layer. The growth of the buffer layer aims to alleviate the lattice mismatch between the substrate and the epitaxial layer, effectively inhibiting the extension of defects to the epitaxial layer, thereby improving the crystal quality of the epitaxial layer.

[0035] Finally, during the epitaxial layer growth stage, the input of silicon source, carbon source and methylhydrazine is further adjusted to meet the growth requirements of the target epitaxial layer. Similar to the buffer layer growth, methylhydrazine continues to act as an n-type doping source and enters the reaction chamber 1 under the carrier of hydrogen, and is incorporated into the growing epitaxial layer. By precisely controlling the flow rate ratio of silicon source, carbon source and methylhydrazine, as well as the temperature and gas pressure of the reaction chamber 1, the growth rate, thickness and doping concentration of the epitaxial layer can be precisely controlled. Throughout the process, the use of methylhydrazine as an n-type doping source simplifies the gas path system, avoids the complexity brought by traditional nitrogen or ammonia doping, and effectively reduces the residual nitrogen in the growth environment, thereby significantly reducing the fluctuation of nitrogen concentration in the epitaxial layer, and finally achieving stable doping of n-type 4H-SiC epitaxial wafer.

[0036] The core innovation of the present application lies in the use of methylhydrazine as an n-type doping source to achieve stable doping of 4H-SiC epitaxial wafer. Compared with the existing technology which uses nitrogen or ammonia as a doping source, the present application has significant technical advantages. When using traditional nitrogen doping, the doping efficiency of nitrogen in the SiC lattice is affected by many factors, resulting in poor consistency of doping concentration between different batches of epitaxial wafers, making it difficult to obtain stable n-type 4H-SiC thin film. Although the use of ammonia doping has some improvements in some aspects, the complex two-stage dilution pipeline system not only increases the cost of equipment and the difficulty of operation and maintenance, but also may introduce additional pollution risk.

[0037] The present application effectively solves the above problems by introducing methylhydrazine as an n-type doping source. As an organic compound, methylhydrazine contains nitrogen atoms in its molecular structure, which 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 and avoids the complex dilution process required for traditional ammonia doping, thereby reducing equipment costs and operation and maintenance difficulties. In addition, the use of methylhydrazine can reduce the residual nitrogen element in the growth environment, thereby effectively reducing the fluctuation of the nitrogen element concentration in the epitaxial layer during the silicon carbide epitaxial growth process, and ultimately achieving stable doping. This stable doping is of great significance for improving the performance uniformity and reliability of SiC power devices, and is an advancement that cannot be matched by existing technology.

[0038] In some embodiments, the specific steps in step S1 include: S11. In the etching stage, after heating the substrate to 1650°C, the hydrogen gas is controlled by the gas supply system to flow into the reaction chamber at a flow rate of 100 slm and maintain the gas pressure of the reaction chamber at 100 mbar until the etching is completed.

[0039] Specifically, the etching stage refers to the pretreatment of the substrate surface before epitaxial growth after the substrate is placed in the reaction chamber 1, to remove the surface oxide layer, damage layer or contaminants, and provide a clean and flat surface for subsequent epitaxial growth. The substrate is heated to 1650°C, which aims to provide sufficient energy to enable hydrogen to effectively react with impurities or defects on the substrate surface, thereby achieving etching. Among them, 1650°C is understood as a preferred temperature, which can ensure the etching efficiency and substrate integrity. The hydrogen gas is controlled by the gas supply system 5 to flow into the reaction chamber 1 at a flow rate of 100 slm, and the hydrogen gas acts as an etching gas to react with the substrate surface at high temperature to remove surface defects. The flow rate of 100 slm is intended to ensure sufficient hydrogen supply to maintain an effective etching rate. At the same time, the gas pressure of the reaction chamber 1 is maintained at 100 mbar, which aims to maintain a stable reaction environment during etching to avoid the adverse effects of gas pressure fluctuations on the epitaxial growth process and ensure the uniformity and repeatability of etching. Until the etching is completed, it can be understood that the etching stage ends when the substrate surface reaches the desired cleanliness and flatness.

[0040] The scheme of the present application heats the substrate to 1650℃, and precisely controls the hydrogen flow rate to 100 slm and the gas pressure in the reaction chamber 1 to be stabilized at 100 mbar, so that the hydrogen can efficiently react with the surface of the silicon carbide substrate under high temperature and low pressure environment, removing the surface oxide, damage layer and other contaminants. Specifically, at a high temperature of 1650℃, hydrogen molecules are endowed with higher activity, which can more effectively decompose and combine with silicon atoms or carbon atoms on the substrate surface to form volatile products (such as SiH4, CH4, etc.), thereby realizing etching of the substrate surface. The hydrogen flow rate of 100 slm ensures sufficient supply of etchant, and the stable gas pressure of 100 mbar helps to maintain the uniformity and stability of the etching reaction, avoiding local over-etching or under-etching. This precise control of process parameters can effectively solve the problems of poor etching effect and unstable substrate surface quality caused by parameter uncertainty in traditional etching methods, and provide an ideal starting surface for the growth of subsequent buffer layer and epitaxial layer.

[0041] Through the above technical scheme, the temperature, hydrogen flow rate and reaction chamber 1 gas pressure of the etching stage are precisely limited, thereby significantly improving the uniformity and repeatability of the etching effect. Specifically, etching at a temperature of 1650℃ can more thoroughly remove defects and contaminants on the substrate surface, while avoiding causing new damage to the substrate. The hydrogen flow rate of 100 slm and the stable gas pressure of 100 mbar ensure the stability and efficiency of the etching process, effectively reducing the roughness and defect density of the substrate surface after etching. Thus, the scheme of the present application lays a solid foundation for the high-quality growth of subsequent buffer layer and epitaxial layer, and helps to obtain n-type 4H-SiC epitaxial wafer with more excellent electrical properties and lower defect density.

[0042] In some embodiments, the silicon source input part 2 is a first bubbling bottle storing trichlorosilane (TCS) liquid; the carbon source input part 3 is a gas device storing ethylene (C2H2) gas; and the doping source input part is a second bubbling bottle storing methylhydrazine (CH6N2) liquid.

[0043] The silicon source input part 2 adopts a first bubbling bottle storing trichlorosilane liquid, specifically referring to using liquid trichlorosilane as a silicon source precursor, and bringing its vapor into the reaction chamber 1 by bubbling. Trichlorosilane is a commonly used silicon source with high purity and stability, and the design of the bubbling bottle helps to precisely control the vapor flow rate through the carrier gas (such as hydrogen), thereby realizing stable input of the silicon source.

[0044] The carbon source input part 3 adopts a gas device storing ethylene gas, specifically, gaseous ethylene is taken as a carbon source precursor, and its flow is directly controlled by a gas flow controller and other devices and input into the reaction chamber 1. Ethylene as a common carbon source, its gaseous form is convenient for accurate metering and conveying by a standard gas control system, ensuring the accuracy of carbon source input.

[0045] The doping source input part 4 adopts a second bubbling bottle storing methylhydrazine liquid, specifically, liquid methylhydrazine is taken as an n-type doping source, and its vapor is brought into the reaction chamber 1 by bubbling. Methylhydrazine as a new type of n-type doping source, its liquid form is conveyed by a bubbling bottle, which can simplify the gas path design and realize accurate control of the doping concentration, and at the same time help to reduce the problem of nitrogen element residue that may be brought by traditional nitrogen doping sources.

[0046] The scheme of the present application specifically configures the silicon source input part 2, the carbon source input part 3 and the doping source input part 4 as the first bubbling bottle, the gas device and the second bubbling bottle, so that various precursors can be accurately introduced into the reaction chamber 1 in their suitable physical forms. Specifically, for liquid precursors trichlorosilane and methylhydrazine, the design of the bubbling bottle allows the carrier gas to pass through the liquid, saturate and carry out the precursor molecules, and its flow can be finely adjusted by the carrier gas flow and the bubbling temperature. For gaseous precursor ethylene, the gas device can directly realize high-precision flow control through the flow controller. Thus, it ensures that the input flow of silicon source, carbon source and n-type doping source is stable and controllable during n-type 4H-SiC epitaxial growth, providing a material basis for stable growth of subsequent buffer layer and epitaxial layer.

[0047] Through the above technical scheme, the specific input forms of silicon source, carbon source and n-type doping source are defined, so that the epitaxial growth control system has higher operability and stability in actual operation. Specifically, using the bubbling bottle to transport liquid precursors (trichlorosilane and methylhydrazine) and the gas device to transport gaseous precursors (ethylene) can effectively ensure the accurate control and stability of the input flow of each component, thereby helping to realize the uniformity of components during epitaxial layer growth, and thus improving the quality and repeatability of n-type 4H-SiC epitaxial wafer. This specific configuration provides a reliable hardware basis for realizing the stable doping target proposed in the present application.

[0048] In some embodiments, the specific steps in step S2 include: S21. During the buffer layer growth phase, hydrogen gas is controlled by the gas supply system to flow at 100 seem through the first bubbler and into the reaction chamber, and ethylene is controlled by the gas device to flow at 40 seem into the reaction chamber, and hydrogen gas is controlled by the gas supply system to flow at 5 seem through the second bubbler and into the reaction chamber, and the gas pressure in the reaction chamber is maintained at 100 mbar until the buffer layer is completed.

[0049] Specifically, during the buffer layer growth phase, in order to achieve precise material deposition and doping control, the trichlorosilane liquid in the silicon source input part 2 (i.e. the first bubbler) is carried out by the hydrogen gas controlled by the gas supply system 5 at a flow rate of 100 seem and sent into the reaction chamber 1. At the same time, the ethylene gas in the carbon source input part 3 (i.e. the gas device) is directly introduced into the reaction chamber 1 at a flow rate of 40 seem. In addition, the methylhydrazine liquid in the doping source input part 4 (i.e. the second bubbler) is carried by the hydrogen gas controlled by the gas supply system 5 at a flow rate of 5 seem and input into the reaction chamber 1. During the entire buffer layer growth process, the gas pressure in the reaction chamber 1 is precisely stabilized at 100 mbar. The setting of these parameters aims to ensure the stable growth of the buffer layer and provide a high-quality substrate surface for the growth of subsequent epitaxial layers.

[0050] The scheme of the present application effectively solves the problem of growth instability caused by parameter uncertainty in the traditional method by precisely quantifying and controlling various process parameters during the buffer layer growth phase. Specifically, the flow rate of hydrogen gas through the first bubbler is set to 100 seem, ensuring the stable and appropriate delivery of the silicon source (trichlorosilane), avoiding the impact of excessive or insufficient silicon source on the quality of the buffer layer. At the same time, the flow rate of ethylene is controlled at 40 seem, allowing the carbon source to be supplied at an optimal ratio with the silicon source, which is conducive to the formation of high-quality silicon carbide crystal structures. In addition, the flow rate of hydrogen gas through the second bubbler is precisely controlled at 5 seem, ensuring the stable and uniform incorporation of the n-type doping source (methylhydrazine), thereby achieving precise regulation of the doping concentration of the buffer layer. On this basis, the gas pressure in the 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 the uniform growth and defect suppression of the buffer layer. It is precisely due to these precise parameter controls that the buffer layer can grow at the expected rate and quality.

[0051] By the above technical solution, the key parameters of the buffer layer growth stage are accurately quantified and controlled, which significantly improves the stability and repeatability of the buffer layer growth. Specifically, the precisely controlled input flow of silicon source, carbon source and doping source and the stable gas pressure of the reaction chamber 1 can effectively ensure the uniform growth of the buffer layer on the substrate and achieve the expected thickness and crystal quality. As a result, the defect density in the buffer layer can be significantly reduced, the surface flatness can be improved, and a more ideal starting interface for the growth of subsequent epitaxial layers can be provided, thereby ultimately helping to obtain an n-type 4H-SiC epitaxial wafer with excellent electrical properties and high reliability.

[0052] In some embodiments, the specific steps in step S3 include: S31. In the epitaxial layer growth stage, hydrogen is controlled by the gas supply system to pass through the first bubbler at a flow rate of 300 sccm and enter the reaction chamber, and ethylene is controlled by the gas device to enter the reaction chamber at a flow rate of 150 sccm, and hydrogen is controlled by the gas supply system to pass through the second bubbler 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 buffer layer is completed.

[0053] Specifically, in the epitaxial layer growth stage, hydrogen is controlled by the gas supply system 5 to pass through the first bubbler at a flow rate of 300 sccm and enter the reaction chamber 1, which aims to precisely control the delivery amount of the silicon source trichlorosilane to ensure sufficient supply of silicon elements in the epitaxial layer and stable growth rate. At the same time, ethylene is controlled by the gas device to enter the reaction chamber 1 at a flow rate of 150 sccm, which aims to provide an appropriate amount of carbon source to form SiC crystal structure together with the silicon source and maintain a suitable carbon-silicon ratio to suppress the generation of defects. In addition, the gas supply system 5 controls hydrogen to pass through the second bubbler at a flow rate of 4 sccm and enter the reaction chamber 1, which is used to bring methylhydrazine molecules into the reaction chamber 1 as an n-type doping source to achieve precise regulation of the doping concentration of the epitaxial layer. In this process, the gas pressure of the reaction chamber 1 is stabilized at 100 mbar, which helps to maintain the uniform distribution of reaction gases in the reaction chamber 1 and stable reaction kinetics, thereby promoting the growth of high-quality epitaxial layers. The whole process continues until the epitaxial layer is completed.

[0054] The scheme of the present application effectively solves the problems of growth rate fluctuation, uneven doping concentration and film quality decline that may occur during the growth of the epitaxial layer by accurately setting the input flow of the silicon source, the carbon source and the n-type doping source and the gas pressure of the reaction chamber 1. Specifically, a hydrogen flow of 300 sccm passes through the first bubble bottle, ensuring stable supply of the silicon source; an ethylene flow of 150 sccm ensures accurate introduction of the carbon source, and the two work together to maintain the ideal carbon-silicon ratio, thereby promoting the formation of high-quality 4H-SiC crystals. At the same time, a hydrogen flow of 4 sccm passes through the second bubble bottle, allowing the methylhydrazine doping source to enter the reaction chamber 1 in a controlled manner, achieving precise control of the n-type doping concentration of the epitaxial layer and avoiding the uneven doping that may be caused by traditional doping sources. In addition, stabilizing the gas pressure of the reaction chamber 1 at 100 mbar helps to optimize the diffusion and adsorption process of the reaction gas, further improving the uniformity and crystalline quality of the epitaxial layer. It is precisely due to the setting of these precise parameters that the epitaxial layer can grow at a stable rate, with uniform doping concentration and excellent crystal quality.

[0055] Through the above technical scheme, the present application can significantly improve the stability and controllability of the growth of n-type 4H-SiC epitaxial layer. Precise flow control and gas pressure maintenance make the growth rate of the epitaxial layer more stable, effectively avoiding uneven film thickness caused by parameter fluctuations. In addition, the precise introduction of the methylhydrazine doping source ensures the uniform distribution of the n-type doping concentration within the epitaxial layer, thereby reducing the inconsistency of device performance. This fine-tuned parameter control ultimately helps to obtain n-type 4H-SiC epitaxial wafers with higher crystalline quality, lower defect density and more excellent electrical performance, providing a solid foundation for the manufacture of high-performance power electronic devices.

[0056] Please refer to Figure 3 , Figure 3 is an n-type 4H-SiC epitaxial growth control device in some embodiments of the present application, applied to an epitaxial growth control system, the epitaxial growth control system comprising 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 n-type 4H-SiC epitaxial growth control device is integrated in the form of a computer program in a back-end control device, comprising: An etching module 100 is used to place a substrate into a reaction chamber, and in the etching phase, 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; The buffer layer growth module 200 is configured to control the silicon source input part, the carbon source input part and the doping source input part to input the silicon source, the carbon source and the n-type doping source into the reaction chamber respectively during the buffer layer growth stage, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows the buffer layer on the substrate as the n-type doping source until the buffer layer is completed. The epitaxial layer growth module 300 is configured to adjust the input of the silicon source input part, the carbon source input part and the doping source input part respectively during the epitaxial layer growth stage, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows the epitaxial layer on the substrate as the n-type doping source until the epitaxial layer is completed.

[0057] In some embodiments, the etching module 100 is configured to control the gas supply system to input hydrogen into the reaction chamber and maintain the gas pressure of the reaction chamber after the substrate is placed into the reaction chamber during the etching stage until the etching is completed: S11. After heating the substrate to 1650℃ during the etching stage, the hydrogen is controlled by the gas supply system to be input into the reaction chamber at a flow rate of 100 slm and the gas pressure of the reaction chamber is maintained to be stable at 100 mbar until the etching is completed.

[0058] In some embodiments, the buffer layer growth module 200 is configured to control the silicon source input part, the carbon source input part and the doping source input part to input the silicon source, the carbon source and the n-type doping source into the reaction chamber respectively during the buffer layer growth stage, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows the buffer layer on the substrate as the n-type doping source until the buffer layer is completed: S21. During the buffer layer growth stage, the hydrogen is controlled by the gas supply system to pass through the first bubble bottle at a flow rate of 100 sccm and be input into the reaction chamber, the ethylene is controlled by the gas device to be input into the reaction chamber at a flow rate of 40 sccm, and the hydrogen is controlled by the gas supply system to pass through the second bubble bottle at a flow rate of 5 sccm and be input into the reaction chamber, and the gas pressure of the reaction chamber is maintained to be stable at 100 mbar until the buffer layer is completed.

[0059] In some embodiments, the epitaxial layer growth module 300 is configured to adjust the input of the silicon source input part, the carbon source input part and the doping source input part respectively during the epitaxial layer growth stage, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows the epitaxial layer on the substrate as the n-type doping source until the epitaxial layer is completed: S31. In the epitaxial layer growth stage, hydrogen is controlled by the gas supply system to flow at 300 seem through the first bubbler and into the reaction chamber, and ethylene is controlled by the gas device to flow at 150 seem into the reaction chamber, and hydrogen is controlled by the gas supply system to flow at 4 seem through the second bubbler and into the reaction chamber, and the pressure in the reaction chamber is kept stable at 100 mbar until the buffer layer is completed.

[0060] Please refer to Figure 4 , Figure 4 A structural schematic diagram of an electronic device provided by an embodiment of the present application is provided, and the electronic device 13 comprises a processor 1301 and a memory 1302, the processor 1301 and the memory 1302 are interconnected and communicate with each other through a communication bus 1303 and / or other forms of connection mechanism (not marked), 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 execute the method in any optional implementation manner of the above-mentioned embodiments, to realize the following functions: 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 keep the pressure in the reaction chamber until the etching is completed; 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 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 the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input them into the reaction chamber, so that the methylhydrazine grows the buffer layer on the substrate as an n-type doping source until the buffer layer is completed; in the epitaxial layer growth stage, the input of the silicon source input part, the carbon source input part and the doping source input part is adjusted respectively, wherein the gas supply system controls the doping source input part to take out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input them into the reaction chamber, so that the methylhydrazine grows the epitaxial layer on the substrate as an n-type doping source until the epitaxial layer is completed.

[0061] The embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to perform the method in any optional implementation manner of the above embodiment, so as to realize the following functions: after the substrate is placed into the reaction chamber, in the etching stage, the gas supply system is controlled to input hydrogen into the reaction chamber and keep the air pressure of the reaction chamber until the etching is completed; 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 the silicon source, the carbon source and the n-type doping source into the reaction chamber, wherein the gas supply system controls the doping source input part to take out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input into the reaction chamber, so that the methylhydrazine grows the buffer layer on the substrate as the n-type doping source until the buffer layer is completed; in the epitaxial layer growth stage, the silicon source input part, the carbon source input part and the doping source input part are adjusted, wherein the gas supply system controls the doping source input part to take out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part by hydrogen and input into the reaction chamber, so that the methylhydrazine grows the epitaxial layer on the substrate as the n-type doping source until the epitaxial layer is completed.

[0062] The computer readable storage medium can be implemented by any type of volatile or nonvolatile storage devices 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 read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0063] In the embodiments of the present application, it should be understood that the disclosed device and method can be implemented by other ways. The device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some communication interfaces, devices or units, and can be electrical, mechanical or other forms.

[0064] In addition, the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0065] Furthermore, each functional module in various embodiments of the present application 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.

[0066] In this paper, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0067] The above is only an embodiment of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

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 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 controls the input of hydrogen into the reaction chamber and maintains the gas pressure of the reaction chamber until the 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 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 carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out through hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow a buffer layer, until the buffer layer is completed. S3. In the epitaxial layer growth stage, the input of the silicon source input part, the carbon source input part and the doping source input part is adjusted respectively, wherein the gas supply system controls the doping source input part to carry out the methylhydrazine molecules in the methylhydrazine liquid pre-stored in the doping source input part out through hydrogen and input into the reaction chamber, so that the methylhydrazine grows as an n-type doping source on the substrate to grow an epitaxial layer, 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 the input of hydrogen into the reaction chamber at a flow rate of 100 slm and maintains the gas pressure of the reaction chamber stable at 100 mbar until the etching is completed.

3. The n-type 4H-SiC epitaxial growth control method according to claim 1, wherein The silicon source input part (2) is a first bubbling bottle storing a trichlorosilane liquid.

4. The n-type 4H-SiC epitaxial growth control method according to claim 3, wherein The carbon source input part (3) is a gas device storing ethylene gas.

5. The n-type 4H-SiC epitaxial growth control method according to claim 4, wherein The doping source input part (4) is a second bubbling bottle storing a methylhydrazine liquid.

6. The n-type 4H-SiC epitaxial growth control method according to claim 5, wherein The specific steps in step S2 include: S21. In the buffer layer growth stage, the gas supply system controls the hydrogen to flow through the first bubbling bottle at a flow rate of 100 sccm and into the reaction chamber, the gas device controls the ethylene to flow into the reaction chamber at a flow rate of 40 sccm, and the gas supply system controls the 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 stable at 100 mbar until the buffer layer is completed.

7. The n-type 4H-SiC epitaxial growth control method according to claim 6, wherein The specific steps in step S3 include: S31. In the epitaxial layer growth stage, the gas supply system controls the hydrogen to flow through the first bubbling bottle at a flow rate of 300 sccm and into the reaction chamber, the gas device controls the ethylene to flow into the reaction chamber at a flow rate of 150 sccm, and the gas supply system controls the 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 stable at 100 mbar until the buffer layer is completed.

8. 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), 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 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 maintaining the gas pressure of the reaction chamber in an etching phase until etching is completed; A buffer layer growth module for, in a buffer layer growth phase, controlling the silicon source input part, the carbon source input part and the doping source input part to respectively input a silicon source, a carbon source and an 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 a methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows a buffer layer on the substrate as an n-type doping source until the buffer layer is completed to grow; An epitaxial layer growth module for, in an epitaxial layer growth phase, respectively adjusting the input of the silicon source input part, the carbon source input part and the doping source input part, wherein the gas supply system controls the doping source input part to carry out methylhydrazine molecules in a methylhydrazine liquid pre-stored in the doping source input part out of the doping source input part and into the reaction chamber by hydrogen, so that the methylhydrazine grows an epitaxial layer on the substrate as an n-type doping source until the epitaxial layer is completed to grow.

9. An electronic device, comprising: A computer program product comprising a processor and a memory storing computer readable instructions which, when executed by the processor, perform the steps of the n-type 4H-SiC epitaxial growth control method of any one of claims 1-7.

10. 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 one of claims 1-7.

Images