Silicon carbide epitaxial device and method for preparing silicon carbide epitaxial layer

Abstract

The present invention provides a silicon carbide epitaxial growth device, comprising: a sample preparation chamber, multiple transfer chambers, a reaction chamber, and a sampling chamber. The sample preparation chamber is adapted to provide space for placing trays loaded with substrate wafers; the multiple transfer chambers are respectively arranged between the sample preparation chamber and the first growth chamber, between the first growth chamber and the second growth chamber, and between the second growth chamber and the sampling chamber, and are adapted to provide temporary storage space for the trays; the reaction chambers comprise: a first growth chamber, a second growth chamber, and a third growth chamber; the first growth chamber is adapted to provide a reaction space for growing a buffer layer; the second growth chamber is adapted to provide a reaction space for growing an N-type epitaxial layer; the third growth chamber is adapted to provide a reaction space for growing a P-type epitaxial layer; the sampling chamber is adapted to place trays loaded with wafers after reactions have completed; each chamber is equipped with an air cushion guide rail, on which multiple automatic air cushion mechanisms are provided; and adjacent chambers are connected by valves.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide epitaxial equipment and the manufacture of silicon carbide epitaxial wafers, and in particular to silicon carbide epitaxial equipment and a method for preparing a silicon carbide epitaxial layer. Background Art

[0002] Silicon carbide epitaxial growth has become a key technology in the manufacturing of the new generation of wide-bandgap silicon carbide power semiconductors. High-quality silicon carbide epitaxial materials are the primary influencing factor in the preparation of high-performance, low-cost silicon carbide power devices.

[0003] Currently, common silicon carbide epitaxial growth equipment primarily uses a single chamber to repeatedly grow multiple layers of silicon carbide epitaxial material. During this process, different reactive gas sources must be repeatedly introduced into the chamber depending on the designed silicon carbide epitaxial layer structure, making it impossible to avoid the influence of different gas sources on epitaxial layer growth. Furthermore, the constant switching of gas sources increases the time required to prepare complex epitaxial layers, limiting their use. Summary of the Invention

[0004] In view of the above problems, a first aspect of the present invention provides a silicon carbide epitaxial growth device, comprising:

[0005] A sample preparation room, adapted to provide space for placing trays loaded with substrate wafers;

[0006] A plurality of transfer chambers are respectively arranged between the sample preparation chamber and the first growth chamber, between the first growth chamber and the second growth chamber, and between the second growth chamber and the sampling chamber, and are suitable for providing temporary storage space for the trays;

[0007] Reaction chamber, including:

[0008] The first growth chamber is adapted to provide a reaction space for growing a buffer layer;

[0009] The second growth chamber is adapted to provide a reaction space for growing an N-type epitaxial layer;

[0010] The third growth chamber is suitable for providing a reaction space for growing a P-type epitaxial layer;

[0011] The sampling chamber is suitable for placing a tray loaded with wafers that have completed the reaction;

[0012] The sample preparation chamber, the multiple transfer chambers, the reaction chamber and the sampling chamber are equipped with air cushion guide rails, multiple automatic air cushion mechanisms are provided on the air cushion guide rails, and two adjacent chambers are connected via valves.

[0013] According to an embodiment of the present invention, the above-mentioned air cushion guide rail includes a first air cushion guide rail and a second air cushion guide rail; the above-mentioned first air cushion guide rail and the above-mentioned second air cushion guide rail have the same structure, both including: a suspension air chamber, a forward air chamber and a backward air chamber; the above-mentioned suspension air chamber, the above-mentioned forward air chamber and the above-mentioned backward air chamber are respectively suitable for controlling the above-mentioned multiple automatic air cushion mechanisms on the above-mentioned air cushion guide rail to present suspension, forward and backward working states; wherein, the above-mentioned suspension air chamber, the above-mentioned forward air chamber and the above-mentioned backward air chamber are respectively equipped with an independent gas inlet and multiple independent gas outlets.

[0014] According to an embodiment of the present invention, the multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are arranged on the same set of first air cushion guide rails; or, the first air cushion guide rails corresponding to the multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are parallel.

[0015] According to an embodiment of the present invention, the second air cushion guide rails corresponding to the sample preparation chamber and the third growth chamber are parallel.

[0016] According to an embodiment of the present invention, the first air cushion guide rail and the second air cushion guide rail are vertically arranged.

[0017] According to an embodiment of the present invention, in a non-operating state, the plurality of automatic air cushion mechanisms are disposed on the second air cushion guide rail close to the sample preparation chamber and on the first air cushion guide rail close to the sampling chamber.

[0018] According to an embodiment of the present invention, the aforementioned multiple automatic air cushion mechanisms have the same structure, and all include a central support area and surrounding blocking areas.

[0019] According to an embodiment of the present invention, the above-mentioned central support area is connected to the above-mentioned surrounding blocking areas at a certain angle; the above-mentioned central support area is suitable for carrying the above-mentioned pallet; the above-mentioned surrounding blocking areas are suitable for gathering the suspended gas, forward gas or backward gas ejected from the above-mentioned suspended air chamber, the above-mentioned forward air chamber and the above-mentioned backward air chamber.

[0020] A second aspect of the present invention provides a method for preparing a silicon carbide epitaxial layer, which is applied to any of the above-mentioned devices, comprising:

[0021] The trays loaded with substrate wafers temporarily stored in the first transfer chamber are transferred to the first growth chamber by using the multiple automatic air cushion mechanisms to grow a buffer layer on the substrate wafers, and the trays on which the wafers with the buffer layer of a set thickness are grown are temporarily stored in the second transfer chamber;

[0022] Transferring the tray in the second transfer chamber to the second growth chamber using the multiple automatic air cushion mechanisms to grow an N-type epitaxial layer on the buffer layer, and temporarily storing the tray containing the wafer with the N-type epitaxial layer of a set thickness in the third transfer chamber;

[0023] Transferring the tray in the third transfer chamber to the third growth chamber using the multiple automatic air cushion mechanisms to grow a P-type epitaxial layer on the N-type epitaxial layer, and temporarily storing the tray containing the wafer with the P-type epitaxial layer of a predetermined thickness in the third transfer chamber;

[0024] Using the multiple automatic air cushion mechanisms, the tray in the third transfer chamber is transferred to the sampling chamber to complete the preparation of the silicon carbide epitaxial layer;

[0025] When corresponding epitaxial layers are grown simultaneously in the first growth chamber, the second growth chamber, and the third growth chamber, the plurality of trays are transferred by the plurality of automatic air cushion mechanisms and temporarily stored in a transfer chamber between two adjacent growth chambers.

[0026] According to an embodiment of the present invention, the method for preparing a silicon carbide epitaxial layer further includes:

[0027] S1: Using the multiple automatic air cushion mechanisms, the tray containing the substrate wafers temporarily stored in the first transfer chamber is transferred to the first growth chamber to grow a buffer layer on the substrate wafers, and the tray containing the wafers with the buffer layer of a set thickness is temporarily stored in the second transfer chamber;

[0028] S2: Using the multiple automatic air cushion mechanisms, transfer the tray in the second transfer chamber to the second growth chamber to grow a first N-type epitaxial layer on the buffer layer, and temporarily store the tray containing the wafer with the first N-type epitaxial layer of a set thickness in a third transfer chamber;

[0029] S3: Using the multiple automatic air cushion mechanisms, transfer the tray in the third transfer chamber to the third growth chamber to grow a first P-type epitaxial layer on the first N-type epitaxial layer, and temporarily store the tray containing the wafer with the first P-type epitaxial layer of a set thickness in the third transfer chamber;

[0030] S4: Using the multiple automatic air cushion mechanisms, transfer the tray in the third transfer chamber to the second growth chamber to grow a second N-type epitaxial layer on the first P-type epitaxial layer, and temporarily store the tray containing the wafer with the second N-type epitaxial layer of a set thickness in the third transfer chamber;

[0031] S5: Using the multiple automatic air cushion mechanisms, transfer the tray in the third transfer chamber to the third growth chamber to grow a second P-type epitaxial layer on the second N-type epitaxial layer, and temporarily store the tray containing the wafer with the second P-type epitaxial layer of a set thickness in the third transfer chamber;

[0032] S6: Repeat S4 to S5 multiple times according to the doping conditions of the silicon carbide epitaxial layer.

[0033] According to an embodiment of the present invention, the silicon carbide epitaxial growth equipment utilizes a multi-chamber structure. By introducing multiple air cushion guides and rationally configuring the relative positions of multiple automatic air cushion mechanisms and the multiple air cushion guides, each chamber in this structure can perform an independent function or be connected in series to achieve the functions of a composite structure. Therefore, the method for preparing silicon carbide epitaxial layers can be performed independently or in a sequential series.

[0034] According to an embodiment of the present invention, the equipment adopts a multi-chamber structure, each chamber is in a stable state and only performs a single function. By switching the corresponding valves, the wafers are quickly transferred between each process, thereby avoiding crosstalk between multiple gas sources and improving the purity and quality of the epitaxial layer. In addition, by introducing multiple air cushion guides and rationally configuring the relative position relationship between multiple automatic air cushion mechanisms and multiple air cushion guides, the automatic air cushion mechanism with the closest distance and the wafer tray are preferentially matched. That is, there is no need to wait when switching from one epitaxial preparation process to another, so that the epitaxial surface of the wafer is not damaged, improving the quality of the epitaxial layer and reducing the generation of impurities and defects.

[0035] According to an embodiment of the present invention, the equipment adopts a multi-chamber structure, introduces multiple air cushion guides, and rationally configures the relative positions of multiple automatic air cushion mechanisms and the multiple air cushion guides. By opening and closing corresponding valves, wafers can be quickly transferred between each process step, completing epitaxial layer preparation in a short period of time, significantly improving the efficiency of epitaxial layer preparation for complex structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0037] Figure 1 A schematic diagram of a silicon carbide epitaxial growth device according to an embodiment of the present invention is shown schematically;

[0038] Figure 2 Schematically shows a schematic diagram of an air cushion guide rail and an automatic air cushion mechanism according to an embodiment of the present invention;

[0039] Figure 3The flowchart of the method for preparing a silicon carbide epitaxial layer according to an embodiment of the present invention is schematically shown;

[0040] Figure 4 A flow chart of a method for preparing a silicon carbide epitaxial layer according to a second embodiment of the present invention is schematically shown;

[0041] Figure 5 A flow chart of a method for preparing a silicon carbide epitaxial layer according to a third embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0043] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0044] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0045] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0046] Figure 1 A schematic diagram of a silicon carbide epitaxial growth device according to an embodiment of the present invention is shown schematically.

[0047] An exemplary embodiment of the present invention provides a chemical vapor deposition apparatus, see Figure 1As shown, it includes: a sample preparation chamber, multiple transfer chambers, a reaction chamber, and a sampling chamber. The sample preparation chamber is suitable for providing a space for placing trays loaded with substrate wafers; multiple transfer chambers are respectively arranged between the sample preparation chamber and the first growth chamber, between the first growth chamber and the second growth chamber, and between the second growth chamber and the sampling chamber, and are suitable for providing temporary storage space for the trays; the reaction chambers include: a first growth chamber, a second growth chamber, and a third growth chamber; wherein: the first growth chamber is suitable for providing a reaction space for growing a buffer layer; the second growth chamber is suitable for providing a reaction space for growing an N-type epitaxial layer; the third growth chamber is suitable for providing a reaction space for growing a P-type epitaxial layer; the sampling chamber is suitable for placing trays loaded with wafers after the reaction is completed; wherein the sample preparation chamber, multiple transfer chambers, the reaction chamber, and the sampling chamber are equipped with air cushion guides, on which multiple automatic air cushion mechanisms are provided; and adjacent chambers are connected by valves.

[0048] According to an embodiment of the present invention, the apparatus employs a multi-chamber structure, each chamber of which can perform an independent function or be connected in series to perform the functions of a composite structure. This allows the silicon carbide epitaxial layer fabrication method to be performed independently or in series, making the method simple, easy to implement, and readily scalable.

[0049] According to an embodiment of the present invention, the equipment adopts a multi-chamber structure. Each chamber in the multi-chamber structure is in a stable state and only performs a single function. The wafer is quickly transferred between each process by switching the corresponding valves, thereby avoiding crosstalk between multiple gas sources, such as crosstalk and memory effect of N and P doping sources, and improving the purity and quality of the epitaxial layer.

[0050] According to an embodiment of the present invention, the equipment utilizes a multi-chamber structure, transferring wafers between various process steps by switching valves, enabling epitaxial layer production to be completed in a short period of time. Furthermore, multiple growth chambers can operate independently and simultaneously to complete epitaxial layer production on multiple wafers, thereby improving the efficiency of epitaxial layer production for multi-layer structures.

[0051] According to an embodiment of the present invention, the sample preparation room, multiple transfer chambers, reaction chambers and sampling chambers are configured as vacuum chambers; the multiple vacuum chambers are respectively configured with independent gas inlets and gas outlets; the multiple gas outlets are connected to stainless steel gas pipes and connected in parallel, and the residual reaction gas is pumped to the tail gas tower through a vacuum pump and emptied after treatment.

[0052] According to an embodiment of the present invention, the device adopts a multi-chamber structure, which avoids the influence of multiple reaction gases, different temperatures and pressures and other process parameters introduced by traditional single-chamber structure equipment on the wafer surface, thereby improving the quality of the prepared epitaxial layer.

[0053] Figure 2 The figure schematically shows an air cushion guide rail and an automatic air cushion mechanism according to an embodiment of the present invention.

[0054] like Figure 2 As shown, Figure 2 Figure (a) shows a cross-sectional view of the air cushion guide rail cut along the long axis. Figure 2 Figure (b) shows a cross-sectional view of the air cushion guide rail cut along the minor axis. Figure 2 Figure (c) shows a front view of the air cushion guide rail.

[0055] According to an embodiment of the present invention, the air cushion guide rail includes a first air cushion guide rail and a second air cushion guide rail; the first air cushion guide rail and the second air cushion guide rail have the same structure, both including: a suspension air chamber, a forward air chamber and a backward air chamber; the suspension air chamber, the forward air chamber and the backward air chamber are respectively suitable for controlling multiple automatic air cushion mechanisms on the air cushion guide rail to present suspension, forward and backward working states.

[0056] According to an embodiment of the present invention, the suspension air chamber, the forward air chamber and the backward air chamber are respectively provided with an independent gas inlet and multiple independent gas outlets; corresponding gases are introduced into each air chamber respectively, and then the gases are ejected from the multiple outlets, so as to form a certain force on the bottom of the multiple automatic air cushion mechanisms on the guide rail, thereby ensuring that the multiple automatic air cushion mechanisms are in a suspended, forward or backward working state.

[0057] According to an embodiment of the present invention, during the entire reaction process, multiple automatic air cushion mechanisms present working states of suspension, forward movement or backward movement, and non-working states of hovering and landing.

[0058] According to an embodiment of the present invention, only when a certain flow of gas is introduced into the suspension air chamber and no gas is introduced into the other two air chambers, can the multiple automatic air cushion mechanisms overcome the effect of gravity and thus float on the air cushion guide rail.

[0059] According to an embodiment of the present invention, after the multiple automatic air cushion mechanisms are in a suspended state, only a certain flow of gas is introduced into the front air chamber. Under the limitation of the oblique air outlet, the gas has a forward pushing force on the multiple automatic air cushion mechanisms, thereby pushing the multiple automatic air cushion mechanisms forward.

[0060] According to an embodiment of the present invention, after the multiple automatic air cushion mechanisms are in a suspended state, only a certain flow of gas is introduced into the backward air chamber. Under the limitation of the oblique air outlet, the gas has a backward pushing force on the multiple automatic air cushion mechanisms, thereby pushing the multiple automatic air cushion mechanisms backward.

[0061] According to an embodiment of the present invention, when multiple automatic air cushion mechanisms are suspended on the air cushion guide rail and move forward or backward to a predetermined position, the same flow rate of gas is introduced into the forward air chamber and the backward air chamber at the same time, so that the forward pushing force and the backward pushing force are equal in magnitude and opposite in direction, thereby offsetting each other, causing the multiple automatic air cushion mechanisms to stop moving and be in a hovering state.

[0062] According to an embodiment of the present invention, when the multiple automatic air cushion mechanisms are in a hovering state, the gases in the three air chambers are closed, so that the multiple automatic air cushion mechanisms land on the air cushion guide rail due to the action of gravity. At this time, the multiple automatic air cushion mechanisms act as the tray where the wafers are located.

[0063] According to an embodiment of the present invention, multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are arranged on the same group of first air cushion rails; or, the first air cushion rails corresponding to the multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are parallel; the second air cushion rails corresponding to the sample preparation chamber and the third growth chamber are parallel; the first air cushion rail and the second air cushion rail are arranged vertically.

[0064] According to an embodiment of the present invention, in a non-operating state, a plurality of automatic air cushion mechanisms are arranged on the second air cushion guide rail close to the sample preparation room and on the first air cushion guide rail close to the sampling room.

[0065] According to an embodiment of the present invention, in a non-working state, two automatic air cushion mechanisms are respectively arranged on the air cushion guide rails adjacent to the sample preparation room and the sampling room. When the tray carrying wafers passes through multiple transfer chambers and multiple growth chambers, an automatic air cushion mechanism that is closer is preferentially selected for transfer.

[0066] According to another embodiment of the present invention, in a non-working state, an automatic air cushion mechanism is provided on the air cushion guide rail adjacent to the sample preparation room, and the automatic air cushion mechanism can transfer the tray carrying the wafers between the vacuum chambers to the entire reaction process.

[0067] According to an embodiment of the present invention, the structures of the plurality of automatic air cushion mechanisms are the same, and all include a central support area and surrounding blocking areas.

[0068] According to an embodiment of the present invention, the central support area is connected to the surrounding blocking areas at a certain angle; the central support area is suitable for carrying a tray containing wafers; the surrounding blocking areas are suitable for gathering the suspended gas, forward gas or backward gas sprayed from the suspended gas chamber, the forward gas chamber and the backward gas chamber, thereby realizing the transportation of wafers to each growth chamber.

[0069] According to an embodiment of the present invention, preferably, the central support area is connected to the surrounding blocking areas at 120 degrees. In the working state, the corresponding gas is introduced into each air chamber, and then the gas is ejected from multiple outlets, forming a certain force on the bottom surface of the automatic air cushion mechanism above the guide rail. This angle can ensure that there is a sufficient amount of suspended gas, forward gas or backward gas to promote the movement of the automatic air cushion mechanism, and enables the automatic air cushion mechanism to work without contact with the air cushion guide rail, thereby reducing the friction between the two to cause accidental damage to the wafers in the tray.

[0070] According to an embodiment of the present invention, in this multi-chamber structure, by introducing multiple air cushion rails and rationally configuring the relative positions of multiple automatic air cushion mechanisms and the multiple air cushion rails, each chamber in this structure is in a stable state and performs only a single function. Therefore, by opening and closing corresponding valves to quickly transfer wafers between various process steps, crosstalk between multiple gas sources can be avoided, thereby improving the purity and quality of the epitaxial layer. Furthermore, by introducing multiple air cushion rails and rationally configuring the relative positions of multiple automatic air cushion mechanisms and the multiple air cushion rails, the closest automatic air cushion mechanism can be optimally matched to the wafer tray. This means that switching from one epitaxial production process to another does not require waiting, thus preserving the epitaxial surface of the wafer, improving the quality of the epitaxial layer, and reducing the generation of impurities and defects. This method shortens the transfer time between each step, ensuring that epitaxial layer production can be completed in a short period of time, significantly improving the efficiency of epitaxial layer production for complex structures.

[0071] Figure 3 The flowchart of the method for preparing a silicon carbide epitaxial layer according to an embodiment of the present invention is schematically shown.

[0072] like Figure 3 As shown, the method for preparing a silicon carbide epitaxial layer may include steps S301 to S304.

[0073] In step S301, a plurality of automatic air cushion mechanisms are used to transfer the tray loaded with substrate wafers temporarily stored in the first transfer chamber to the first growth chamber to grow a buffer layer on the substrate wafer, and the tray containing the wafer with the buffer layer of the set thickness is temporarily stored in the second transfer chamber.

[0074] According to an embodiment of the present invention, a plurality of automatic air cushion mechanisms are used to transport a tray loaded with substrate wafers from a sample preparation room to a first transfer room, including:

[0075] Place the tray loaded with substrate wafers into the corresponding position in the sample preparation room;

[0076] After repeated vacuuming, flush the sample preparation chamber with inert gas;

[0077] Open the first valve between the sample preparation room and the first transfer room;

[0078] After the tray in the sample preparation room is transferred to the first transfer room by using multiple automatic air cushion mechanisms, the first valve is closed to complete the sample loading state.

[0079] According to an embodiment of the present invention, a plurality of automatic air cushion mechanisms are used to transfer the tray in the first transfer chamber to the first growth chamber to grow a buffer layer on the substrate wafer, and the tray on which the wafer having the buffer layer grown thereon is temporarily stored in the second transfer chamber, including:

[0080] Adjusting the temperature and pressure of the first growth chamber to set values, and introducing the first growth gas from the gas inlet of the first growth chamber; wherein the first growth gas includes silicon source gas, carbon source gas, and buffer source gas;

[0081] When the pressure in the first growth chamber is stable and equal to the pressure in the first transfer chamber, opening the second valve between the first growth chamber and the first transfer chamber;

[0082] The tray in the first transfer chamber is transferred to the first growth chamber by using multiple automatic air cushion mechanisms, and the second valve is closed to complete the sample loading state;

[0083] After the buffer layer of the set thickness is grown in the first growth chamber, the third valve is opened, and the tray in the first growth chamber is transferred to the second transfer chamber using multiple automatic air cushion mechanisms, and the third valve is closed.

[0084] In step S302, multiple automatic air cushion mechanisms are used to transfer the tray in the second transfer chamber to the second growth chamber to grow an N-type epitaxial layer on the buffer layer, and the tray containing the wafer with the N-type epitaxial layer of a set thickness is temporarily stored in the third transfer chamber.

[0085] According to an embodiment of the present invention, a plurality of automatic air cushion mechanisms are used to transfer the tray in the second transfer chamber to the second growth chamber to grow an N-type epitaxial layer on the buffer layer, and the tray is temporarily stored in the third transfer chamber, including:

[0086] Adjusting the temperature and pressure of the second growth chamber to set values, and introducing a second growth gas from the gas inlet of the second growth chamber; wherein the second growth gas includes a silicon source gas, a carbon source gas, and an N-type dopant source gas;

[0087] When the pressure in the second growth chamber is stable and equal to the pressure in the second transfer chamber, opening the fourth valve between the second growth chamber and the second transfer chamber;

[0088] The tray in the second transfer chamber is transferred to the second growth chamber by using multiple automatic air cushion mechanisms, and the fourth valve is closed to complete the state of waiting for sample loading;

[0089] After the N-type epitaxial layer of the set thickness is grown in the second growth chamber, the fifth valve is opened, the tray in the second growth chamber is transferred to the third transfer chamber using multiple automatic air cushion mechanisms, and the fifth valve is closed.

[0090] In step S303, multiple automatic air cushion mechanisms are used to transfer the tray in the third transfer chamber to the third growth chamber to grow a P-type epitaxial layer on the N-type epitaxial layer, and the tray containing the wafer with the P-type epitaxial layer of a set thickness is temporarily stored in the third transfer chamber.

[0091] According to an embodiment of the present invention, a plurality of automatic air cushion mechanisms are used to transfer the tray in the third transfer chamber to the third growth chamber to grow a P-type epitaxial layer on the N-type epitaxial layer, and the tray containing the wafer with the P-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber, including:

[0092] Adjusting the temperature and pressure of the third growth chamber to set values, and introducing a third growth gas from the gas inlet of the third growth chamber; wherein the third growth gas includes a silicon source gas, a carbon source gas, and a P-type dopant source gas;

[0093] When the pressure in the third growth chamber is stable and equal to the pressure in the third transfer chamber, opening the sixth valve between the third growth chamber and the third transfer chamber;

[0094] The tray in the third transfer chamber is transferred to the third growth chamber by using multiple automatic air cushion mechanisms, and the sixth valve is closed to complete the state of waiting for sample loading;

[0095] After the P-type epitaxial layer of the set thickness is grown in the third growth chamber, the sixth valve is opened, the tray in the third growth chamber is transferred to the third transfer chamber using multiple automatic air cushion mechanisms, and the sixth valve is closed.

[0096] In step S304, multiple automatic air cushion mechanisms are used to transfer the trays in the third transfer chamber to the sampling chamber to complete the preparation of the silicon carbide epitaxial layer; wherein, when the corresponding epitaxial layers are grown simultaneously in the first growth chamber, the second growth chamber, and the third growth chamber, multiple automatic air cushion mechanisms are used to transfer multiple trays and temporarily store them in the transfer chamber between two adjacent growth chambers.

[0097] According to an embodiment of the present invention, a plurality of automatic air cushion mechanisms are used to transfer the tray of the third transfer chamber to the sampling chamber to complete the preparation of the silicon carbide epitaxial layer, including:

[0098] After repeatedly evacuating the third transfer chamber and the sampling chamber, flush the third transfer chamber and the sampling chamber with inert gas;

[0099] Open the seventh valve between the third transfer chamber and the sampling chamber, use multiple automatic air cushion mechanisms to transfer the tray in the third transfer chamber to the sampling chamber, close the seventh valve, and complete the sample discharge state.

[0100] According to an embodiment of the present invention, the valve in the entire process may also be an inert gas wall, through which the vacuum chambers in the same pressure state are softly isolated, thereby ensuring that the gases in the vacuum chambers do not interfere with each other.

[0101] Figure 4 The flowchart of the method for preparing a silicon carbide epitaxial layer according to the second embodiment of the present invention is schematically shown.

[0102] like Figure 4 As shown, the method for preparing a silicon carbide epitaxial layer may further include steps S401 to S406.

[0103] In step S401, a tray loaded with substrate wafers temporarily stored in a first transfer chamber is transferred to a first growth chamber using multiple automatic air cushion mechanisms to grow a buffer layer on the substrate wafers. The tray containing the wafers with the buffer layer of a predetermined thickness is then temporarily stored in a second transfer chamber.

[0104] In step S402, a plurality of automatic air cushion mechanisms are used to transfer the tray in the second transfer chamber to the second growth chamber to grow a first N-type epitaxial layer on the buffer layer, and the tray containing the wafer with the first N-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber.

[0105] In step S403, the tray in the third transfer chamber is transferred to the third growth chamber using multiple automatic air cushion mechanisms to grow a first P-type epitaxial layer on the first N-type epitaxial layer, and the tray containing the wafer with the first P-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber.

[0106] In step S404, the tray in the third transfer chamber is transferred to the second growth chamber using multiple automatic air cushion mechanisms to grow a second N-type epitaxial layer on the first P-type epitaxial layer, and the tray containing the wafer with the second N-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber.

[0107] In step S405, the tray in the third transfer chamber is transferred to the third growth chamber using multiple automatic air cushion mechanisms to grow a second P-type epitaxial layer on the second N-type epitaxial layer, and the tray containing the wafer with the second P-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber.

[0108] In step S406: S404 to S405 are repeated multiple times according to the doping conditions of the silicon carbide epitaxial layer; wherein, when the corresponding epitaxial layers are repeatedly grown in the second growth chamber and the third growth chamber, multiple trays are transferred by multiple automatic air cushion mechanisms and temporarily stored in the transfer chamber between two adjacent growth chambers.

[0109] According to an embodiment of the present invention, the doping concentrations of the first N-type epitaxial layer, the second N-type epitaxial layer... and the m-th N-type epitaxial layer are different; the doping concentrations of the first P epitaxial layer, the second P epitaxial layer... and the m-th P epitaxial layer are different, thereby preparing a complex epitaxial layer structure with multiple dopings.

[0110] Figure 5 A flow chart of a method for preparing a silicon carbide epitaxial layer according to a third embodiment of the present invention is schematically shown.

[0111] like Figure 5 As shown, the method for preparing a silicon carbide epitaxial layer may further include steps S501 to S403.

[0112] In step S501, a tray loaded with substrate wafers temporarily stored in a first transfer chamber is transferred to a first growth chamber using multiple automatic air cushion mechanisms to grow a buffer layer on the substrate wafers. The tray containing the wafers with the buffer layer of a predetermined thickness is then temporarily stored in a second transfer chamber.

[0113] In step S502, the tray in the second transfer chamber is transferred to the second growth chamber using multiple automatic air cushion mechanisms to grow an N-type epitaxial layer on the buffer layer, and the tray containing the wafer with the N-type epitaxial layer of a predetermined thickness is temporarily stored in the third transfer chamber.

[0114] In step S503, multiple automatic air cushion mechanisms are used to transfer the trays in the third transfer chamber to the sampling chamber to complete the preparation of the silicon carbide epitaxial layer. When the corresponding epitaxial layers are grown simultaneously in the first growth chamber and the second growth chamber, multiple automatic air cushion mechanisms are used to transfer multiple trays and temporarily store them in the second transfer chamber.

[0115] According to the embodiment of the present invention, the detailed preparation process of each step corresponding to the second and third embodiments is the same as that of the first embodiment, and the reaction conditions are adaptively adjusted according to actual doping requirements.

[0116] According to an embodiment of the present invention, the silicon carbide epitaxial growth equipment adopts a multi-chamber structure, and by introducing multiple air cushion guides and rationally configuring the relative position relationship between multiple automatic air cushion mechanisms and multiple air cushion guides. In this structure, each chamber can perform an independent function, or it can be connected in series to complete the function of the composite structure. Therefore, the method for preparing the silicon carbide epitaxial layer can be independent or carried out in series in sequence. In other words, with the cooperation of the third transfer chamber, two independent functions can be completed, that is, the first growth chamber, the second growth chamber and the third growth chamber can be connected in series to complete the growth of the composite structure, or a simple epitaxial layer growth can be completed only in the first growth chamber and the second growth chamber.

[0117] According to an embodiment of the present invention, the equipment adopts a multi-chamber structure, each chamber is in a stable state and only performs a single function. By switching the corresponding valves, the wafers are quickly transferred between each process, thereby avoiding crosstalk between multiple gas sources and improving the purity and quality of the epitaxial layer. In addition, by introducing multiple air cushion guides and rationally configuring the relative position relationship between multiple automatic air cushion mechanisms and multiple air cushion guides, the automatic air cushion mechanism with the closest distance and the wafer tray are preferentially matched. That is, there is no need to wait when switching from one epitaxial preparation process to another, so that the epitaxial surface of the wafer is not damaged, improving the quality of the epitaxial layer and reducing the generation of impurities and defects.

[0118] According to an embodiment of the present invention, the equipment adopts a multi-chamber structure, introduces multiple air cushion guides, and rationally configures the relative positions of multiple automatic air cushion mechanisms and the multiple air cushion guides. By opening and closing corresponding valves, wafers can be quickly transferred between each process step, completing epitaxial layer preparation in a short period of time, significantly improving the efficiency of epitaxial layer preparation for complex structures.

[0119] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A silicon carbide epitaxial growth device, comprising: A sample preparation room, adapted to provide space for placing trays loaded with substrate wafers; A plurality of transfer chambers are respectively arranged between the sample preparation chamber and the first growth chamber, between the first growth chamber and the second growth chamber, and between the second growth chamber and the sampling chamber, and are suitable for providing temporary storage space for the trays; Reaction chamber, including: The first growth chamber is adapted to provide a reaction space for growing a buffer layer; The second growth chamber is adapted to provide a reaction space for growing an N-type epitaxial layer; The third growth chamber is suitable for providing a reaction space for growing a P-type epitaxial layer; The sampling chamber is suitable for placing a tray loaded with wafers that have completed the reaction; The sample preparation chamber, the multiple transfer chambers, the reaction chamber, and the sampling chamber are equipped with air cushion guide rails, and multiple automatic air cushion mechanisms are provided on the air cushion guide rails; and adjacent chambers are connected by valves; The air cushion guide rail includes a first air cushion guide rail and a second air cushion guide rail; The first air cushion guide rail and the second air cushion guide rail have the same structure, both comprising: a suspension air chamber, a forward air chamber, and a backward air chamber; The suspension air chamber, the forward air chamber, and the backward air chamber are respectively adapted to control the plurality of automatic air cushion mechanisms on the air cushion guide rail to present suspension, forward, and backward working states; Wherein, the suspension air chamber, the front air chamber and the rear air chamber are respectively configured with an independent gas inlet and multiple independent gas outlets.

2. The device according to claim 1, wherein The multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are arranged on the same set of first air cushion guide rails; or, the first air cushion guide rails corresponding to the multiple transfer chambers, the first growth chamber, the second growth chamber and the sampling chamber are parallel.

3. The device according to claim 1, wherein The second air cushion guide rails corresponding to the sample preparation chamber and the third growth chamber are parallel.

4. The apparatus according to claim 1, wherein The first air cushion guide rail and the second air cushion guide rail are arranged vertically.

5. The apparatus according to claim 1, wherein In a non-working state, the plurality of automatic air cushion mechanisms are arranged on the second air cushion guide rail close to the sample preparation room and on the first air cushion guide rail close to the sampling room.

6. The device according to claim 5, wherein The multiple automatic air cushion mechanisms have the same structure, and all include a central support area and surrounding blocking areas.

7. The apparatus according to claim 6, wherein The central support area is connected to the surrounding blocking areas at a certain angle; The central support area is suitable for carrying the pallet; The surrounding blocking area is suitable for gathering the suspended gas, forward gas or backward gas ejected from the suspended gas chamber, the forward gas chamber and the backward gas chamber.

8. A method for preparing a silicon carbide epitaxial layer, applied to the apparatus according to any one of claims 1 to 7, comprising: The tray loaded with substrate wafers temporarily stored in the first transfer chamber is transferred to the first growth chamber by using the multiple automatic air cushion mechanisms to grow a buffer layer on the substrate wafers, and the tray on which the wafers with the buffer layer of a set thickness are grown is temporarily stored in the second transfer chamber; Transferring the tray in the second transfer chamber to the second growth chamber using the multiple automatic air cushion mechanisms to grow an N-type epitaxial layer on the buffer layer, and temporarily storing the tray on which the wafer having the N-type epitaxial layer of a set thickness is grown in the third transfer chamber; Transferring the tray in the third transfer chamber to the third growth chamber using the multiple automatic air cushion mechanisms to grow a P-type epitaxial layer on the N-type epitaxial layer, and temporarily storing the tray containing the wafer with the P-type epitaxial layer of a set thickness in the third transfer chamber; Using the multiple automatic air cushion mechanisms, the tray of the third transfer chamber is transferred to the sampling chamber to complete the preparation of the silicon carbide epitaxial layer; When corresponding epitaxial layers are grown simultaneously in the first growth chamber, the second growth chamber, and the third growth chamber, the plurality of trays are transferred by the plurality of automatic air cushion mechanisms and temporarily stored in a transfer chamber between two adjacent growth chambers.

9. The method according to claim 8, further comprising: S1: using the multiple automatic air cushion mechanisms to transfer the tray loaded with substrate wafers temporarily stored in the first transfer chamber to the first growth chamber to grow a buffer layer on the substrate wafer, and temporarily storing the tray on which the wafer with the buffer layer of a set thickness is grown in the second transfer chamber; S2: Transferring the tray in the second transfer chamber to the second growth chamber using the multiple automatic air cushion mechanisms to grow a first N-type epitaxial layer on the buffer layer, and temporarily storing the tray containing the wafer with the first N-type epitaxial layer of a set thickness in a third transfer chamber; S3: Using the multiple automatic air cushion mechanisms, transfer the tray in the third transfer chamber to the third growth chamber to grow a first P-type epitaxial layer on the first N-type epitaxial layer, and temporarily store the tray containing the wafer with the first P-type epitaxial layer of a set thickness in the third transfer chamber; S4: using the multiple automatic air cushion mechanisms to transfer the tray in the third transfer chamber to the second growth chamber to grow a second N-type epitaxial layer on the first P-type epitaxial layer, and temporarily storing the tray containing the wafer with the second N-type epitaxial layer of a set thickness in the third transfer chamber; S5: Using the multiple automatic air cushion mechanisms, transfer the tray in the third transfer chamber to the third growth chamber to grow a second P-type epitaxial layer on the second N-type epitaxial layer, and temporarily store the tray containing the wafer with the second P-type epitaxial layer of a set thickness in the third transfer chamber; S6: Repeat S4 to S5 multiple times according to the doping conditions of the silicon carbide epitaxial layer.

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