Silicon carbide epitaxial furnace, pretreatment method and semiconductor device
By forming a silicon carbide or silicon-rich silicon carbide coating on the surface of the cover of the silicon carbide epitaxial furnace, the defect problem caused by falling particles is solved, and the electrical performance and service life of the device are improved.
Patent Information
- Application Number
- CN202512042787.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-21
AI Technical Summary
In the fabrication of silicon carbide epitaxial devices, defects caused by falling particles (such as downfall defects) lead to incomplete epitaxial layer growth, affecting the electrical performance and lifespan of the device.
A coating, especially a silicon carbide or silicon-rich silicon carbide coating, is formed on the surface of the cover of the silicon carbide epitaxial furnace. The particles on the cover are fixed and prevented from falling off by adjusting the furnace environment parameters and gas ratios during coating deposition.
It effectively reduces defects caused by particle shedding, improves the quality and reliability of semiconductor devices, and enhances yield and long-term operational stability of devices.
Smart Images
Figure CN121896729A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of semiconductor device fabrication technology, and particularly relates to a silicon carbide epitaxial furnace and pretreatment method, and a semiconductor device. Background Technology
[0002] As a key piece of equipment in semiconductor device manufacturing, the silicon carbide epitaxial furnace directly determines the growth quality of the epitaxial layer and the performance of the device.
[0003] In related technologies, defects caused by particle shedding (such as downfall defects) are prone to occur during the fabrication of silicon carbide epitaxial devices. These shedding particles directly damage the growth integrity of the epitaxial layer, leading to defects in the epitaxial layer, which in turn causes a sharp drop in the breakdown voltage of the semiconductor device, seriously affecting the electrical performance and lifespan of the device. Summary of the Invention
[0004] The purpose of this application is to provide a silicon carbide epitaxial furnace and pretreatment method, as well as a semiconductor device, in order to solve the problem of defects caused by falling objects on semiconductor devices in conventional technologies.
[0005] The first aspect of this application provides a pretreatment method for a silicon carbide epitaxial furnace, the silicon carbide epitaxial furnace including an air-floating tray and a cover, the air-floating tray being used to place the device to be processed, and the cover being disposed on one side of the air-floating tray and surrounding at least a portion of the air-floating tray; The preprocessing method is applied before processing the device to be processed, and the preprocessing method includes: A coating layer is formed on the surface of the cover.
[0006] In some embodiments of this application, the covering coating satisfies at least one of the following: The covering coating is a silicon carbide coating; The thickness of the coating is greater than 20 μm.
[0007] In some embodiments of this application, the covering coating is a silicon-rich silicon carbide coating.
[0008] In some embodiments of this application, forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace to preset parameters; A carbon source gas and a silicon source gas in a preset ratio are introduced to deposit the coating on the surface of the cover.
[0009] In some embodiments of this application, the environmental parameters include at least one of pressure, carrier gas flow rate, and temperature.
[0010] In some embodiments of this application, the number of the coverings is multiple, and the multiple coverings are continuously arranged around the air flotation tray along the circumference of the air flotation tray; The process of forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 80-140 SLM, and the temperature is 1500-1580℃. A carbon source gas and a silicon source gas with a carbon-to-silicon ratio of 0.5-0.8 are introduced, and the flow rate of the carbon source gas is 10-30 SCCM; the cover coating is deposited on the surface of the cover.
[0011] In some embodiments of this application, there are multiple air flotation trays, and the multiple air flotation trays are arranged in a circular array; there are multiple coverings, and the multiple coverings are arranged in a circular array within the array of multiple air flotation trays, and the multiple coverings are configured in a one-to-one correspondence with the multiple air flotation trays; The process of forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 200-350 SLM, and the temperature is 1500-1600℃; A carbon source gas and a silicon source gas with a carbon-to-silicon ratio of 0.8-1.0 are introduced, and the flow rate of the carbon source gas is 30-120 SCCM; the cover coating is deposited on the surface of the cover.
[0012] In some embodiments of this application, the carrier gas is hydrogen.
[0013] In a second aspect of this application, a silicon carbide epitaxial furnace is provided, wherein the silicon carbide epitaxial furnace performs pretreatment using the pretreatment method described above.
[0014] A third aspect of the embodiments of this application also provides a semiconductor device, which is prepared by a silicon carbide epitaxial furnace as described above.
[0015] The beneficial effects of this application are as follows: In the silicon carbide epitaxial furnace and pretreatment method and semiconductor device of this application, the silicon carbide epitaxial furnace includes an air-floating tray and a cover. The air-floating tray is used to place the device to be processed, and the cover is disposed on one side of the air-floating tray and surrounds at least a portion of the air-floating tray. The pretreatment method of the silicon carbide epitaxial furnace is applied before processing the device to be processed, and the pretreatment method includes: forming a cover coating on the surface of the cover. The pretreatment method of this application sets a cover coating on the cover to fix the particles on the cover, which is beneficial to prevent the particles on the cover from falling onto the device to be processed during the subsequent processing of the device to be processed, thereby improving the quality of the prepared semiconductor device. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of a silicon carbide epitaxial furnace provided in an embodiment of this application; Figure 2 This is another structural schematic diagram of a silicon carbide epitaxial furnace provided in one embodiment of this application; Figure 3 Another schematic diagram of the silicon carbide epitaxial furnace provided in an embodiment of this application; Figure 4 A schematic diagram illustrating the steps of a pretreatment method for a silicon carbide epitaxial furnace provided in another embodiment of this application; Figure 5 This is a schematic diagram of the structure of a silicon carbide epitaxial furnace provided in another embodiment of this application; Figure 6 This is a schematic diagram of the structure of a cover provided in one embodiment of this application; Figure 7 This is a schematic diagram of the structure of a silicon carbide epitaxial furnace provided in another embodiment of this application; Figure 8 This is a schematic diagram of the structure of a cover provided in another embodiment of this application.
[0017] Specific element symbol explanation: 100-covering part, 110-covering coating, 200-air flotation tray, 300-device to be processed. Detailed Implementation
[0018] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.
[0019] It should be noted that when a component is referred to as being "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0021] It is important to understand that silicon carbide, with its excellent material properties such as wide bandgap, high breakdown electric field, and high thermal conductivity, has become a core candidate material for fabricating high-performance power devices. Silicon carbide epitaxial furnaces, as key equipment in semiconductor device manufacturing, directly determine the growth quality of the epitaxial layer and the device performance. The core structure of this type of silicon carbide epitaxial furnace includes an air-floating tray and a cover. The air-floating tray provides a stable support platform for the silicon carbide substrate (the device to be processed), ensuring that the substrate is fixed in position and subjected to uniform stress during subsequent epitaxial growth. The cover is located on one side of the air-floating tray and is arranged around at least part of it. Its core function is to cooperate with the furnace cavity to form a closed reaction space, while guiding the process gas flow uniformly across the substrate surface, providing stable environmental conditions for epitaxial layer growth. Together, these two components constitute the key structural basis for silicon carbide epitaxial growth.
[0022] In the fabrication of silicon carbide epitaxial devices, defects caused by particle shedding (such as downfall defects) are a critical issue affecting device reliability. Specifically, the cover material, as a key structural component inside the furnace cavity, is prone to forming a loose particle layer (such as undensified silicon carbide particles) on its surface under long-term high temperature, airflow erosion, and epitaxial reaction conditions. These particles have weak adhesion to the cover material surface. In subsequent epitaxial processes, factors such as the flow of carrier gas (such as hydrogen), temperature fluctuations inside the furnace cavity, or airflow disturbances can cause these loose particles on the cover material surface to detach and fall onto the substrate surface supported by the air-bearing tray. These falling particles directly disrupt the growth integrity of the epitaxial layer, leading to defects in the epitaxial layer. This, in turn, causes a sharp drop in the breakdown voltage of the semiconductor device, severely affecting the device's electrical performance and lifespan, becoming a key technical problem restricting the large-scale, high-quality fabrication of silicon carbide epitaxial devices.
[0023] Based on this, this application improves upon traditional silicon carbide epitaxial furnaces and pretreatment methods, as well as semiconductor devices.
[0024] Please see Figures 1 to 3 , Figure 1 This is a schematic diagram of the silicon carbide epitaxial furnace provided in this embodiment; Figure 2 This is another structural schematic diagram of the silicon carbide epitaxial furnace provided in this embodiment; Figure 3 This is another structural schematic diagram of the silicon carbide epitaxial furnace provided in this embodiment. (See attached diagram.) Figure 2 and 3 As shown, the yellow component is the cover 100, and the granular structure on the yellow component is the particle on the cover 100. The silicon carbide epitaxial furnace of this embodiment includes an air-floating tray 200 and a cover 100. The air-floating tray 200 is used to place the device to be processed 300, and the cover 100 is disposed on one side of the air-floating tray 200 and surrounds at least a portion of the air-floating tray 200. The pretreatment method of the silicon carbide epitaxial furnace is applied before processing the device to be processed 300, and the pretreatment method includes forming a cover coating 110 on the surface of the cover 100.
[0025] It should be explained that a silicon carbide epitaxial furnace is a specialized piece of equipment used in semiconductor manufacturing to grow silicon carbide epitaxial layers. It achieves uniform growth of the epitaxial layer through precise control of the process environment. The air-floating tray 200 is a core component in the silicon carbide epitaxial furnace used to support the device 300 to be processed. Utilizing the principle of air floating, it forms an air cushion to support the device 300, ensuring its stability and flatness during processing and helping to avoid damage caused by mechanical contact. The cover 100 is a protective component located on one side of the air-floating tray 200, arranged around part or all of the air-floating tray 200, and has the function of blocking impurities and regulating airflow. The device 300 to be processed is a semiconductor substrate that needs to undergo epitaxial layer growth in the silicon carbide epitaxial furnace. The cover coating 110 is a thin film layer formed on the surface of the component through a deposition process. It has dense and robust characteristics and is commonly used for surface protection, particle fixation, or performance optimization, enhancing the structural stability of the component surface.
[0026] It is understood that the overlay coating 110 in this embodiment can firmly fix the originally loose particles on the surface of the cover 100, preventing the particles from falling off and onto the surface of the device 300 during subsequent processing due to airflow disturbance, thus reducing the generation of downfall defects from the source. Furthermore, reducing the fatal defects caused by particle falling off can prevent a decline in key electrical properties such as device breakdown voltage, while increasing the usable area of the epitaxial wafer, improving yield and long-term operational stability of the device.
[0027] In some embodiments of this application, the overlay coating 110 is a silicon carbide coating.
[0028] It is understood that the silicon carbide coating in this embodiment has high density and strong adhesion, which can firmly wrap the loose particles on the surface of the cover 100, forming a stable physical barrier to resist the high temperature and airflow impact in the epitaxial furnace, preventing particles from falling off and contaminating the substrate, and fundamentally reducing the generation of downfall defects. Furthermore, the silicon carbide coating has excellent high-temperature resistance, can withstand operating temperatures above 1500°C in the epitaxial furnace for extended periods, and is resistant to hydrogen gas flow erosion and is not easily worn off, reducing the frequency of repeated pretreatment, improving production efficiency, and lowering process costs.
[0029] In some embodiments of this application, the overlay coating 110 is a silicon-rich silicon carbide coating.
[0030] Understandably, the silicon-rich properties of the silicon-rich silicon carbide coating enhance the adhesion between the coating and the cover 100, and the dense structure can firmly wrap the loose particles on the surface of each cover 100.
[0031] In some embodiments, the thickness of the overlay coating 110 is greater than 20 μm.
[0032] It is understood that the use of a thick coating 110 with a thickness greater than 20 μm in this embodiment can more fully wrap the loose particles on the surface of the cover 100, forming a stronger physical barrier to resist the impact of airflow and temperature fluctuations in the epitaxial furnace, preventing particles from falling off from the coating gaps and reducing downfall defects from the source.
[0033] In some embodiments of this application, please refer to Figure 4 , Figure 4 This embodiment illustrates the steps of the pretreatment method for a silicon carbide epitaxial furnace provided in this embodiment; the formation of a cover coating 110 on the surface of the cover 100 in this embodiment includes: S100: Adjust the environmental parameters inside the silicon carbide epitaxial furnace to the preset parameters; Specifically, by precisely controlling key conditions such as furnace temperature, pressure, and carrier gas flow rate, the furnace environment is optimized for the reaction of carbon and silicon source gases. A suitable temperature ensures gas reactivity, stable pressure prevents porosity during coating formation, and a reasonable carrier gas flow rate regulates airflow distribution, ensuring uniform coating growth on the surface of the cover 100. This step provides a stable foundation for subsequent gas reactions and coating deposition, improving the bonding strength between the coating and the surface of the cover 100 and preventing coating detachment or structural loosening due to unsuitable environmental conditions.
[0034] S200: Introduce a preset ratio of carbon source gas and silicon source gas to deposit a cover coating 110 on the surface of the cover 100.
[0035] Understandably, the two gases undergo a chemical reaction in a pre-set stable environment, gradually depositing on the surface of the cover 100 to form a uniform and dense coating 110. The pre-set gas ratio can precisely control the proportion of the coating components, giving the coating the characteristics of being silicon-rich and structurally stable; it can firmly wrap the originally loose particles on the surface of the cover 100 and form a strong bond with the surface of the cover 100, fundamentally blocking the path of particle detachment.
[0036] In some embodiments of this application, the environmental parameters include at least one of pressure, carrier gas flow rate, and temperature.
[0037] Please refer to the embodiments described in this application. Figure 2 And see Figure 5 and Figure 6 , Figure 5 A schematic diagram of the silicon carbide epitaxial furnace provided in this embodiment is shown. Figure 6 A schematic diagram of the structure of the cover 100 provided in this embodiment is shown. The silicon carbide epitaxial furnace in this embodiment is a horizontal monolithic silicon carbide epitaxial furnace. In this embodiment, there are multiple cover 100s, and these multiple cover 100s are continuously arranged around the air-floating tray 200 along its circumference. Forming a coating 110 on the surface of the cover 100 includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 80-140 SLM, and the temperature is 1500-1580℃. A carbon source gas and a silicon source gas with a carbon-to-silicon ratio of 0.5-0.8 are introduced, and the flow path of the carbon source gas is 10-30 SCCM; a cover coating 110 is deposited on the surface of the cover 100.
[0038] Please refer to the embodiments described in this application. Figure 3 And see Figure 7 and Figure 8 , Figure 7 A schematic diagram of the silicon carbide epitaxial furnace provided in this embodiment is shown. Figure 8 A schematic diagram of the structure of the cover 100 provided in this embodiment is shown. The silicon carbide epitaxial furnace in this embodiment is a horizontal multi-wafer silicon carbide epitaxial furnace. In this embodiment, there are multiple air-floating trays 200, arranged in a circular array; there are also multiple cover pieces 100, arranged in a circular array within the array of air-floating trays 200, with each cover piece 100 corresponding to one of the air-floating trays 200. Forming a coating 110 on the surface of the cover 100 includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 200-350 SLM, and the temperature is 1500-1600℃; Carbon source gas and silicon source gas with a carbon-to-silicon ratio of 0.8-1.0 are introduced, and the carbon source gas flow rate is 30-120 SCCM; a cover coating 110 is deposited on the surface of the cover 100.
[0039] In some embodiments of this application, the carrier gas is hydrogen.
[0040] Furthermore, in order to better implement the pretreatment method of the silicon carbide epitaxial furnace in any of the above embodiments, based on the pretreatment method of the silicon carbide epitaxial furnace described above, this application embodiment also provides a silicon carbide epitaxial furnace, which performs pretreatment using the pretreatment method described above.
[0041] Furthermore, in order to better implement the silicon carbide epitaxial furnace in any of the above embodiments, based on the silicon carbide epitaxial furnace described above, this application embodiment also provides a semiconductor device, which is prepared using the silicon carbide epitaxial furnace described above.
[0042] In some embodiments, the semiconductor device includes a silicon carbide epitaxial layer, which is prepared using a silicon carbide epitaxial furnace as described above.
[0043] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0044] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.
[0045] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.
[0046] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.
[0047] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A pretreatment method for a silicon carbide epitaxial furnace, characterized in that, The silicon carbide epitaxial furnace includes an air-floating tray and a cover. The air-floating tray is used to place the device to be processed, and the cover is disposed on one side of the air-floating tray and surrounds at least a portion of the air-floating tray. The preprocessing method is applied before processing the device to be processed, and the preprocessing method includes: A coating layer is formed on the surface of the cover.
2. The pretreatment method for silicon carbide epitaxial furnace according to claim 1, characterized in that, The coating material satisfies at least one of the following: The coating is a silicon carbide coating; The thickness of the coating is greater than 20 μm.
3. The pretreatment method for silicon carbide epitaxial furnace according to claim 2, characterized in that, The coating is a silicon-rich silicon carbide coating.
4. The pretreatment method for silicon carbide epitaxial furnace according to claim 1, characterized in that, The process of forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace to preset parameters; A carbon source gas and a silicon source gas in a preset ratio are introduced to deposit the coating on the surface of the cover.
5. The pretreatment method for silicon carbide epitaxial furnace according to claim 4, characterized in that, The environmental parameters include at least one of pressure, carrier gas flow rate, and temperature.
6. The pretreatment method for silicon carbide epitaxial furnace according to claim 5, characterized in that, The number of the coverings is multiple, and the multiple coverings are continuously arranged around the air flotation tray along the circumference of the air flotation tray; The process of forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 80-140 SLM, and the temperature is 1500-1580℃. A carbon source gas and a silicon source gas with a carbon-to-silicon ratio of 0.5-0.8 are introduced, and the flow rate of the carbon source gas is 10-30 SCCM; the cover coating is deposited on the surface of the cover.
7. The pretreatment method for silicon carbide epitaxial furnace according to claim 5, characterized in that, The number of air flotation trays is multiple, and the multiple air flotation trays are arranged in a circular array; the number of coverings is multiple, and the multiple coverings are arranged in a circular array within the array of multiple air flotation trays, and the multiple coverings are set in a one-to-one correspondence with the multiple air flotation trays. The process of forming a coating layer on the surface of the cover includes: Adjust the environmental parameters inside the silicon carbide epitaxial furnace until the pressure is 60-120 mbar, the carrier gas flow rate is 200-350 SLM, and the temperature is 1500-1600℃; A carbon source gas and a silicon source gas with a carbon-to-silicon ratio of 0.8-1.0 are introduced, and the flow rate of the carbon source gas is 30-120 SCCM; the cover coating is deposited on the surface of the cover.
8. The pretreatment method for silicon carbide epitaxial furnace according to claim 6 or 7, characterized in that, The carrier gas is hydrogen.
9. A silicon carbide epitaxial furnace, characterized in that, The silicon carbide epitaxial furnace is pretreated using the pretreatment method described in any one of claims 1 to 8.
10. A semiconductor device, characterized in that, The semiconductor device is prepared using the silicon carbide epitaxial furnace as described in claim 9.