Liquid phase epitaxy graphite boat capable of reducing mother liquor residue and growth method

Abstract

The invention provides a liquid phase epitaxy graphite boat for reducing mother liquor residue, which comprises a mother liquor cover plate, a mother liquor plate, a substrate plate and a bottom plate, the mother liquor plate is provided with at least one mother liquor groove, the back surface of the mother liquor plate is provided with at least one first groove, the substrate plate is provided with a substrate groove for placing a substrate and a second groove, and the bottom plate is provided with at least one second groove. The substrate plate is arranged between the mother liquor plate and the bottom plate in a sliding manner, and the bottom plate is provided with a pushing structure which is used for jacking up the substrate at the first groove and enabling the substrate to incline towards one side of the second groove. Through the design of the pushing structure, after epitaxial growth of each layer is completed, the horizontally-arranged substrate can be inclined, mother liquor flows into the second groove of the substrate plate due to gravity, the purpose of removing the mother liquor is achieved, mother liquor residues on the epitaxial surface after growth of each layer of epitaxial film are effectively reduced, and the production efficiency is improved. Mother liquor mutual pollution caused by residue of the upper layer of epitaxial mother liquor is avoided, meanwhile, the available area of an epitaxial film is increased, and the epitaxial wafer cracking risk caused by cooling stress of the residual mother liquor is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid phase epitaxial growth of thin film materials, and in particular relates to a liquid phase epitaxial graphite boat capable of reducing mother liquid residue and a growth method. Background Art

[0002] Liquid phase epitaxy is the mainstream preparation technology for HgCdTe epitaxial thin films due to its low growth difficulty and good crystal quality. Liquid phase epitaxy is divided into three preparation methods: vertical immersion method, horizontal push boat method and tilt boat method. Among them, the vertical immersion method is that the substrate is vertically immersed in the mother liquid for epitaxial growth, and the mother liquid is pulled out by vertical upward movement after the growth is completed. The mother liquid is separated from the epitaxial surface by gravity, and there is less mother liquid residue on the epitaxial surface; the tilt boat method is that after the growth is completed, the growth tool is tilted, and the mother liquid is separated from the substrate. There is also no problem of large-area mother liquid residue; and the horizontal push boat liquid phase epitaxial preparation method is to scrape off the mother liquid by the relative movement between the mother liquid plate and the substrate plate. It is also the only preparation method in the existing liquid phase epitaxial growth method that can achieve multi-layer epitaxial growth in the same round of epitaxial growth.

[0003] At present, most of the mother liquid removal on the epitaxial surface prepared by the horizontal push-boat method adopts a scraper design. In order to minimize the residual mother liquid, the gap between the substrate and the mother liquid plate is required to be very small, generally within 30um. The fine gap control makes it difficult to control the growth in mass production, and the small gap control is very easy to scratch the epitaxial surface during the push-boat. In addition, due to the good wettability of mercury cadmium telluride mother liquid on the epitaxy, even if the gap control is very small, it is difficult to effectively scrape it off, and a large amount of mother liquid will still remain on the epitaxial surface. Moreover, for multi-layer epitaxial growth, the residual mother liquid of the previous layer of epitaxy will lead to mutual contamination of the mother liquids, resulting in uneven epitaxial components. At the same time, incomplete removal of the last layer of mother liquid will also affect the available area of ​​the epitaxial film and increase the probability of epitaxial cracking caused by the cooling stress of the residual mother liquid. Summary of the invention

[0004] The purpose of the present invention is to provide a liquid phase epitaxial graphite boat with reduced mother liquor residue, which can at least solve some of the defects in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A liquid phase epitaxial graphite boat for reducing mother liquid residue, comprising a mother liquid cover plate, a mother liquid plate, a substrate plate and a bottom plate, wherein the mother liquid plate is provided with at least one mother liquid groove, the back of the mother liquid plate is provided with at least one first groove, the substrate plate is provided with a substrate groove for placing a substrate and a second groove adjacent to the substrate groove for collecting residual mother liquid on an epitaxial wafer after growth, the substrate plate is slidably arranged between the mother liquid plate and the bottom plate, and the bottom plate is provided with a pushing structure for lifting the substrate at the first groove and tilting the substrate toward the second groove.

[0007] Furthermore, the pushing structure includes at least one protrusion, which is arranged corresponding to the first groove. A gasket that can be pushed upward by the protrusion is provided in the substrate groove. The gasket is located below the substrate, and the top of the gasket has a transmission part that lifts the substrate and tilts the substrate.

[0008] Furthermore, the transmission part is a first inclined plane arranged on the top of the gasket, and the inclination direction and inclination angle of the first inclined plane are consistent with the preset inclination direction and inclination angle of the substrate.

[0009] Furthermore, the protrusion has a wedge surface, and the lower part of the gasket has an inclined surface matching the wedge surface.

[0010] Furthermore, a side of the protrusion facing away from the wedge surface is a transition slope.

[0011] Furthermore, a third groove is provided on the bottom plate, the protrusion is placed at the bottom of the third groove, the bottom of the gasket is in contact with the bottom of the third groove, and the projection of each mother liquid tank on the bottom plate is located in the third groove.

[0012] Furthermore, a side wall of the third groove on one side of the sliding direction of the substrate plate is a second inclined surface facing upward.

[0013] Furthermore, the substrate groove is a T-shaped stepped groove structure.

[0014] In addition, the present invention also provides a liquid phase epitaxial growth method, the above-mentioned liquid phase epitaxial graphite boat, the method comprises the following steps:

[0015] S1, placing the liquid phase epitaxial graphite boat horizontally into a horizontal epitaxial furnace, and heating the horizontal epitaxial furnace to a mother liquid homogenization temperature;

[0016] S2, cooling the horizontal epitaxial furnace to the crystallization point temperature of the mother liquid of epitaxial growth, pulling the substrate plate horizontally so that the substrate is located below the mother liquid tank containing the mother liquid, and starting epitaxial growth;

[0017] S3. After the epitaxial growth is completed, the substrate plate is pulled horizontally to move the substrate to the first groove, and the substrate is lifted and tilted by a pushing structure to allow the residual mother liquid on the substrate to flow into the second groove.

[0018] Furthermore, the above-mentioned liquid phase epitaxial growth method also includes step S4, continuing to pull the substrate plate horizontally, the pushing structure cancels the pushing effect on the substrate, the substrate resumes horizontal placement, and then repeats the above-mentioned steps S2 and S3, and so on, to perform multi-layer epitaxial growth.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention combines the characteristics of the horizontal push boat method and the tilt boat method. Through the design of the push structure, after the epitaxial growth is completed, the horizontally placed substrate is tilted, and the residual mother liquid on the surface of the film flows into the second groove of the substrate plate due to gravity, thereby achieving the purpose of reducing the residual mother liquid and increasing the available area for epitaxy.

[0021] (2) The liquid phase epitaxial graphite boat provided by the present invention can be used for multi-layer epitaxial growth. After each layer of epitaxial growth is completed, the horizontally placed substrate is tilted to effectively reduce the mother liquid residue on the epitaxial surface after the growth of each layer of epitaxial film, avoid the mother liquid from the previous layer of epitaxial mother liquid residue and cause mutual contamination, while increasing the available area of ​​the epitaxial film and reducing the risk of epitaxial cracking caused by the cooling stress of the residual mother liquid.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a mother liquid cover plate in an embodiment of the present invention;

[0024] Figure 2 is a top view of a mother liquid plate in an embodiment of the present invention;

[0025] Figure 3 is a bottom view of a mother liquid plate in an embodiment of the present invention;

[0026] Figure 4 is a schematic structural diagram of a substrate plate in an embodiment of the present invention;

[0027] Figure 5 is a top view of a gasket in an embodiment of the present invention;

[0028] Figure 6 is a side view of a gasket in an embodiment of the present invention;

[0029] Figure 7 is a schematic structural diagram of a bottom plate in an embodiment of the present invention;

[0030] Figure 8 Schematic diagram of the liquid phase epitaxial growth process in an embodiment of the present invention;

[0031] Fig. 9 Schematic diagram of temperature control curve of liquid phase epitaxial growth in an embodiment of the present invention;

[0032] Fig.10 This is a microscopic image of the epitaxial growth material that has not been prepared with improvement;

[0033] Fig.11 This is a microscopic examination picture of an epitaxially grown material prepared by using the liquid phase epitaxial graphite boat of the present invention.

[0034] Explanation of the reference numerals: 1. mother liquid cover plate; 2. mother liquid plate; 3. substrate plate; 4. gasket; 5. bottom plate; 6. substrate; 21. first mercury source protection groove; 22. mother liquid groove; 23. first mercury volatilization groove; 24. second mercury source protection groove; 25. second mercury volatilization groove; 26. first groove; 31. substrate groove; 32. second groove; 41. first inclined surface; 51. third groove; 52. protrusion; 53. second inclined surface. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0039] like Figures 1 to 9 As shown, this embodiment provides a liquid phase epitaxial graphite boat for reducing mother liquid residue, including a mother liquid cover plate 1, a mother liquid plate 2, a substrate plate 3 and a bottom plate 5, wherein the substrate plate 3 is arranged on the bottom plate 5, the mother liquid plate 2 is arranged on the substrate plate 3, the mother liquid cover plate 1 is covered on the mother liquid plate 2, and the mother liquid cover plate 1 and the mother liquid plate 2 are preferably detachably connected, including but not limited to fixing the mother liquid cover plate 1 and the mother liquid plate 2 with threaded fasteners such as screws.

[0040] like Figure 2 and Figure 3 As shown, the mother liquid plate 2 is provided with at least one mother liquid tank 22. For multi-layer epitaxial growth, each of the mother liquid tanks 22 is correspondingly filled with the mother liquid required for one layer of epitaxial growth. The back of the mother liquid plate 2 is provided with at least one first groove 26 to give way to the movement of the substrate 6. Preferably, each mother liquid tank 22 is provided with a first groove 26 on one side of the substrate moving direction (i.e., the right side in the figure), and the depth of the first groove 26 is not less than the preset tilt height of the substrate 6. Figure 4 As shown, the substrate plate 3 is provided with a substrate groove 31 for placing the substrate 6 and a second groove 32 for collecting the residual mother liquid on the epitaxial wafer after growth. The second groove 32 is arranged adjacent to the substrate groove 31. The substrate plate 3 can slide freely left and right between the mother liquid plate 2 and the bottom plate 5 so that the substrate 6 is directly opposite to the corresponding mother liquid groove 22. The bottom plate 5 is provided with a pushing structure for lifting the substrate 6 and tilting the substrate 6 toward the second groove 32. During the lifting process, the substrate 6 can enter the first groove 26, and the first groove 26 provides a moving space for the substrate 6 to tilt upward. Among them, the front side of the mother liquid plate 2 is its surface facing the mother liquid cover plate 1, and the back side of the mother liquid plate 2 is its surface facing the substrate plate 3.

[0041] During operation, for single-layer epitaxial growth, it is only necessary to hold the mother liquid for epitaxial growth in a mother liquid tank 33, place the liquid phase epitaxial graphite boat horizontally into the horizontal epitaxial furnace, and heat the horizontal epitaxial furnace to the mother liquid homogenization temperature; then, cool the horizontal epitaxial furnace to the crystallization point temperature of the mother liquid for epitaxial growth, pull the substrate plate 3 horizontally, so that the substrate 6 is located below the mother liquid tank 22 containing the mother liquid, and start epitaxial growth; after the epitaxial growth is completed, pull the substrate plate 3 horizontally, move the substrate 6 to the first groove 26, lift and tilt the substrate 6 through the pushing structure, and allow the residual mother liquid on the substrate 6 to flow into the second groove 32.

[0042] For multi-layer epitaxial growth, the mother liquid of each layer of epitaxial growth is placed in each mother liquid tank 22 in turn, and the crystallization point of the mother liquid is lowered in turn according to the growth order; then the liquid phase epitaxial graphite boat is placed horizontally in the horizontal epitaxial furnace, and the horizontal epitaxial furnace is heated to the mother liquid homogenization temperature; then, the horizontal epitaxial furnace is cooled to the crystallization point temperature of the first layer of mother liquid, the substrate plate 3 is pulled horizontally, so that the substrate 6 is located below the mother liquid tank 22 containing the first layer of mother liquid, and the first layer of epitaxial growth is started; after the first layer of epitaxial growth is completed, the substrate plate 3 is pulled horizontally to move the substrate 6 to the first groove 26, and the substrate 6 is lifted and tilted by the push structure to make the substrate 6 The residual mother liquid on the bottom 6 flows into the second groove 32; then the substrate plate 3 is continuously pulled horizontally, the pushing structure cancels the pushing effect on the substrate 6, and the substrate 6 resumes its horizontal placement, and then the horizontal epitaxial furnace is cooled to the crystallization point temperature of the second layer of mother liquid, and the substrate plate 3 is pulled horizontally so that the substrate 6 is located below the mother liquid tank 22 containing the second layer of mother liquid, and the second layer of epitaxial growth begins; after the second layer of epitaxial growth is completed, the substrate plate 3 is pulled horizontally so that the substrate 6 moves to the first groove 26, and the substrate 6 is lifted and tilted by the pushing structure, so that the residual mother liquid on the substrate 6 flows into the second groove 32, and so on, to complete the multi-layer epitaxial growth process. The liquid phase epitaxial growth process provided in the present embodiment combines the features of the horizontal push boat method and the tilt boat method. Through the design of the push structure, after the epitaxial growth is completed, the horizontally placed substrate 6 is tilted, and the residual mother liquid on the surface of the film flows into the second groove 32 of the substrate plate 3 due to gravity, thereby achieving the purpose of reducing the residual mother liquid and increasing the available area for epitaxy; and multi-layer epitaxial growth can be performed. After the growth of each layer of epitaxial film is completed, the horizontally placed substrate 6 is tilted, which effectively reduces the residual mother liquid on the epitaxial surface after the growth of each layer of epitaxial film, and avoids the mother liquid from being contaminated with each other due to the residual mother liquid of the previous layer.

[0043] As a specific implementation method, Figure 8As shown, the pushing structure includes at least one protrusion 52, and the protrusion 52 is arranged corresponding to the first groove 26. A gasket 4 that can be pushed upward by the protrusion 52 is provided in the substrate groove 31, and the gasket 4 is located below the substrate 6. The top of the gasket 4 has a transmission part that pushes up the substrate 6 and tilts the substrate 6. In one embodiment, the upper surface of the gasket 4 is designed as a first inclined surface 41 as a transmission part that tilts the substrate 6, and the inclination direction and inclination angle of the first inclined surface are consistent with the preset inclination direction and inclination angle of the substrate. When the substrate plate is pulled horizontally, the gasket 4 is pushed upward by the protrusion 52, and the substrate 6 above the gasket 4 is lifted up accordingly. Since the top of the gasket 4 is an inclined structure, the substrate 6 is tilted toward the second groove 32 during the lifting process, so that the mother liquid remaining after the epitaxial growth on the substrate 6 flows into the second groove 32 under the action of gravity; the substrate plate 3 continues to be pulled horizontally, the gasket 4 slides out of the position of the protrusion 52, and the gasket 4 falls back to the initial position. At the same time, the inclined substrate 6 resumes its horizontal position.

[0044] Preferably, the size of the gasket 4 is designed to be slightly smaller than the size of the substrate 6, so that the substrate 6 can be placed horizontally in the substrate groove 31 during epitaxial growth; the size of the mother liquid groove 22 is slightly smaller than the size of the substrate 6, so that the substrate 6 forms a pressure edge on the mother liquid groove 22, which can prevent the mother liquid from flowing into the gap between the substrate 6 and the gasket 4.

[0045] Optionally, the substrate groove 31 is designed to be a T-shaped stepped groove structure, the substrate 6 is placed at the horizontal section of the T-shape, and the gasket 4 is placed at the vertical section of the T-shape. When the gasket 4 lifts the substrate 6, the end of the substrate 6 away from the second groove 32 rises, and the end of the substrate 6 close to the second groove 32 abuts against the side wall of the substrate groove 31. In this way, the substrate 6 swings around its end close to the second groove 32, thereby forming an inclination that enables the residual mother liquid to flow to the second groove 32.

[0046] Preferably, in the width direction of the substrate plate 3, the width of the second groove 32 is greater than the width of the substrate groove 31, so that during the substrate tilting process, all the mother liquid remaining on the epitaxial wafer flows into the second groove.

[0047] Optionally, the protrusion 52 is designed to have a wedge surface, and the lower part of the gasket 4 has an inclined surface that matches the wedge surface. In the process of horizontally pulling the substrate plate 3, the inclined surface of the lower part of the gasket 4 contacts the wedge surface of the protrusion 52, and the gasket 4 is lifted by the wedge surface. Further, the side of the protrusion facing away from the wedge surface is designed as a transition inclined surface, so that the gasket 4 slides down from the protrusion 52 smoothly along the transition inclined surface of the protrusion 52 during the process of sliding out of the protrusion 52, thereby ensuring the stability of the lifting movement of the gasket 4. In this embodiment, the longitudinal section of the protrusion 52 is designed to be a trapezoid, and the longitudinal section of the lower part of the gasket 4 is designed to be an inverted trapezoid, and the two oblique sides of the inverted trapezoidal structure of the lower part of the gasket 4 are made to correspond to the two oblique sides of the protrusion 52; specifically, the oblique side on the right side of the lower part of the gasket 4 can fit with the oblique side on the left side of the protrusion 52, and the oblique side on the left side of the lower part of the gasket 4 can fit with the oblique side on the right side of the protrusion 52.

[0048] Optionally, a third groove 51 is provided on the bottom plate 5, and each of the protrusions 52 is spaced apart at the bottom of the third groove 51 along the sliding direction of the substrate plate 3, and at the same time, the bottom of the gasket 4 is in contact with the bottom of the third groove 51, and each of the mother liquid tanks 22 is projected on the bottom plate 5 and is located in the third groove 51. Preferably, the upper surface of the protrusion 52 is designed not to be higher than the upper surface of the bottom plate 5, so that the substrate plate 3 can be placed on the upper surface of the bottom plate 5, and the bottom plate 5 supports the substrate plate 3, thereby ensuring the stability of the substrate plate 3 during the horizontal pulling process.

[0049] Furthermore, the second groove 32 on the substrate plate 3 can be designed as a through-hole structure that passes through from top to bottom, so that the residual mother liquid from the epitaxial growth flows into the third groove 51 of the base plate 5 through the second groove 32, and the third groove 51 is used to collect the residual mother liquid, thereby preventing the second groove 32 from being too small to accommodate multiple layers of epitaxial growth residual mother liquid.

[0050] Preferably, the side wall of the third groove 51 on the sliding direction side of the substrate plate 3 can be designed as a second inclined surface 53 facing upward, so that the second inclined surface 53 can replace a protrusion 52 and is used to push the gasket 4 after the last layer of epitaxial growth is completed, thereby simplifying the structure; and after the last layer of epitaxial growth is completed, the gasket 4 slides out of the third groove 51 from the second inclined surface 53. At this time, the gasket 4 is always in a state of pushing the substrate upward, and the epitaxial wafer grown on the substrate 6 remains tilted, which is beneficial to prevent the mother liquid between the edge of the epitaxial wafer and the substrate plate 3 from sticking, making it easier to take the wafer out.

[0051] In some embodiments, Figure 2 and Figure 3As shown, the front of the mother liquid plate 2 is provided with a first mercury source protection groove 21 and a first mercury volatilization groove 23, the first mercury source protection groove 21 and the first mercury volatilization groove 23 are connected, and the first mercury volatilization groove 23 is connected to the outside. The first mercury source protection groove 21 is used to place a mercury protection source, which includes but is not limited to mercury telluride powder. The first mercury source protection groove 21 is recessed from the front to the back side of the mother liquid plate 2 and does not penetrate the back of the mother liquid plate 2; the first mercury volatilization groove 23 is an annular groove arranged around the mother liquid groove 22. In this embodiment, by providing the first mercury volatilization groove 23 connected to the first mercury source protection groove 21, the mother liquid can maintain a stable mercury volatilization amount during the epitaxial growth process, suppress epitaxial macroscopic corrugation defects, and improve the flatness of the epitaxial product.

[0052] Regarding the way in which the first mercury volatilization tank 23 is connected to the outside, in some embodiments, at least one through hole connected to the outside can be provided on the mother liquid cover plate 1, and the first mercury volatilization tank 23 is connected to the through hole, so that the first mercury volatilization tank 23 is connected to the outside.

[0053] Preferably, a second mercury volatilization groove 25 is further provided on the back of the mother liquid plate 2, and the second mercury volatilization groove 25 is connected to the first mercury volatilization groove 23, so that the mercury pressure above and below the mother liquid can be consistent, and the mercury pressure above the mother liquid is prevented from being too high, and the mother liquid is squeezed into the gap below the substrate 6, causing the mother liquid to stick to the back of the epitaxial growth and making it difficult to remove the wafer. Specifically, the second mercury volatilization groove 25 can also be designed as an annular groove arranged around the mother liquid groove 22, and the second mercury volatilization groove 25 is connected to the first mercury volatilization groove 23 through a conducting hole.

[0054] Furthermore, a second mercury source protection groove 24 is provided on the front side of the mother liquid plate 2, and the second mercury source protection groove 24 is used to place a mercury protection source, and the mercury protection source includes but is not limited to mercury telluride powder; the second mercury source protection groove 24 and the first mercury source protection groove 21 are respectively located at the two ends of the mother liquid plate 2, which is beneficial to improving the uniformity of the mother liquid temperature. Each of the mother liquid grooves 22 is connected in sequence and connected to the second mercury source protection groove 24. By controlling the amount of mercury source added in the second mercury source protection groove 24, the appropriate mercury loss amount of the mother liquid can be controlled, and at the same time, the stability of mercury loss in the growing mother liquid is improved to prevent epitaxial thickness fluctuations and epitaxial surface defects caused by severe mercury loss.

[0055] The liquid phase epitaxial materials prepared by the unimproved graphite boat in the prior art and the liquid phase epitaxial graphite boat provided by the present invention were examined under a microscope, and the results are as follows: Fig.10 and Fig.11 As shown. Fig.10 It can be seen that there is a lot of mother liquid remaining on the surface of the prepared epitaxial material. Fig.11It can be seen that the surface of the epitaxial material prepared by the liquid phase epitaxial graphite boat of the present invention is clean and there is no mother liquid residue; this shows that the liquid phase epitaxial graphite boat designed by the present invention and the epitaxial material obtained by liquid phase epitaxial growth using the liquid phase epitaxial graphite boat overcome the defects existing in the prior art and significantly improve the quality of the epitaxial material.

[0056] In summary, the liquid phase epitaxial graphite boat provided by the present invention is designed with a push structure. After each layer of epitaxial growth is completed, the horizontally placed substrate can be tilted, and the mother liquid flows into the second groove of the substrate plate due to gravity, thereby achieving the purpose of removing the mother liquid, effectively reducing the mother liquid residue on the epitaxial surface after the growth of each layer of epitaxial film, avoiding mutual contamination of mother liquids due to the residual mother liquid of the previous layer of epitaxial film, and at the same time increasing the available area of ​​the epitaxial film, reducing the risk of epitaxial cracking due to cooling stress of the residual mother liquid.

[0057] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A liquid phase epitaxial graphite boat for reducing mother liquor residue, characterized in that: It includes a mother liquid cover plate, a mother liquid plate, a substrate plate and a bottom plate, wherein the mother liquid plate is provided with at least one mother liquid groove, the back of the mother liquid plate is provided with at least one first groove, the substrate plate is provided with a substrate groove for placing a substrate and a second groove adjacent to the substrate groove for collecting residual mother liquid on the epitaxial wafer after growth, the substrate plate is slidably arranged between the mother liquid plate and the bottom plate, and the bottom plate is provided with a pushing structure for lifting the substrate at the first groove and tilting the substrate toward the second groove.

2. The liquid phase epitaxial graphite boat for reducing mother liquid residue according to claim 1, characterized in that: The pushing structure includes at least one protrusion, which is arranged corresponding to the first groove. A gasket that can be pushed upward by the protrusion is provided in the substrate groove. The gasket is located below the substrate, and a transmission part is provided on the top of the gasket to lift the substrate and tilt the substrate.

3. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 2, characterized in that: The transmission part is a first inclined plane arranged on the top of the gasket, and the inclination direction and inclination angle of the first inclined plane are consistent with the preset inclination direction and inclination angle of the substrate.

4. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 2, characterized in that: The protrusion has a wedge surface, and the lower part of the gasket has an inclined surface matched with the wedge surface.

5. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 4, characterized in that: The side of the protrusion facing away from the wedge surface is a transition slope.

6. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 2, characterized in that: The bottom plate is provided with a third groove, the protrusion is placed at the bottom of the third groove, the bottom of the gasket is in contact with the bottom of the third groove, and the projection of each mother liquid tank on the bottom plate is located in the third groove.

7. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 6, characterized in that: The side wall of the third groove on the sliding direction side of the substrate plate is a second inclined surface facing upward.

8. The liquid phase epitaxial graphite boat for reducing mother liquid residue as claimed in claim 1, characterized in that: The substrate groove is a T-shaped stepped groove structure.

9. A liquid phase epitaxial growth method, characterized in that: Using the liquid phase epitaxial graphite boat according to any one of claims 1 to 8, the method comprises the following steps: S1, placing the liquid phase epitaxial graphite boat horizontally into a horizontal epitaxial furnace, and heating the horizontal epitaxial furnace to a mother liquid homogenization temperature; S2, cooling the horizontal epitaxial furnace to the crystallization point temperature of the mother liquid of epitaxial growth, pulling the substrate plate horizontally so that the substrate is located below the mother liquid tank containing the mother liquid, and starting epitaxial growth; S3. After the epitaxial growth is completed, the substrate plate is pulled horizontally to move the substrate to the first groove, and the substrate is lifted and tilted by a pushing structure to allow the residual mother liquid on the substrate to flow into the second groove.

10. The liquid phase epitaxial growth method according to claim 9, characterized in that: The method further includes step S4, continuing to pull the substrate plate horizontally, the pushing structure cancels the pushing effect on the substrate, the substrate resumes horizontal placement, and then repeating the above steps S2 and S3, and so on, to perform multi-layer epitaxial growth.

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