An epitaxial structure of a semiconductor device and a method for manufacturing the same, and a semiconductor device
By designing patterned structures in different regions of the substrate and adjusting the heat distribution, the problem of temperature non-uniformity caused by lattice mismatch in semiconductor device manufacturing is solved, thereby improving the uniformity of the product.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DYNAX SEMICON
- Filing Date
- 2021-08-13
- Publication Date
- 2026-07-21
AI Technical Summary
In the semiconductor device manufacturing process, lattice mismatch caused by the growth of epitaxial materials on heterogeneous substrates leads to uneven substrate surface temperature, affecting the uniformity of the product.
By designing patterned structures in different regions of the substrate, the surface area can be increased or decreased to adjust the heat distribution and make the substrate surface temperature uniform.
By adjusting the heat distribution on the substrate surface, the uniformity of the epitaxial structure and semiconductor devices was improved, and the problem of temperature non-uniformity caused by warping was solved.
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Figure CN115705998B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to an epitaxial structure of a semiconductor device and its fabrication method, and a semiconductor device. Background Technology
[0002] Semiconductor devices, including HEMT, LED, UV, VCSEL, etc., are widely used in various industries. For example, the most common LED is widely used in signal lights, home lighting, automotive lighting, etc.; while fast chargers and 5G communication require HEMT devices.
[0003] In the semiconductor device manufacturing process, epitaxial growth is always performed on a substrate. Due to the lack of homogeneous substrates, materials such as GaN and AlN are typically grown on heterogeneous substrates, such as sapphire, silicon, and SiC. Growth on heterogeneous substrates inevitably presents the problem of lattice mismatch between the epitaxial material and the substrate, leading to warping ("concave" or "convex") on the originally flat substrate during growth. Figure 1 As shown. The presence of warpage results in a lower temperature on the substrate surface away from the tray, while the temperature is higher on the surface closer to the tray, such as... Figure 2 Therefore, the uneven temperature of the substrate surface leads to poor product uniformity. Summary of the Invention
[0004] In view of this, embodiments of the present invention provide an epitaxial structure of a semiconductor device and a method for fabricating the same, as well as a semiconductor device, to reduce the non-uniformity of the substrate surface temperature and thereby improve the uniformity of the product.
[0005] In a first aspect, embodiments of the present invention provide an epitaxial structure for a semiconductor device, including a substrate and a multilayer epitaxial layer located on one side of the substrate;
[0006] The substrate includes a first surface on the side away from the epitaxial layer, the first surface including a first region and a second region, the first region including at least the edge of the first surface, and the second region including at least the center of the first surface;
[0007] The lattice constant of the epitaxial layer material is different from that of the substrate material;
[0008] At least the first region includes a patterned structure, and per unit area, the surface area of the first region is greater than the surface area of the second region;
[0009] Alternatively, at least the second region includes a patterned structure, and the surface area of the first region is smaller than the surface area of the second region per unit area.
[0010] Optionally, the substrate includes a first substrate;
[0011] The lattice constant of the epitaxial layer material is less than the lattice constant of the first substrate material, and the first region in the first substrate is warped toward the epitaxial layer side;
[0012] At least the first region includes a patterned structure, and the surface area of the first region per unit area is greater than the surface area of the second region.
[0013] Optionally, the first substrate includes a first substrate body portion and a first substrate protrusion portion connected to each other, the first substrate protrusion portion being located on the side of the first substrate body portion away from the epitaxial layer, and the coverage area of the first substrate protrusion portion being smaller than the coverage area of the first substrate body portion.
[0014] At least a portion of the first substrate protrusion is located in the first region, and the surface of the first substrate protrusion located in the first region includes the patterned structure.
[0015] Optionally, the substrate includes a second substrate;
[0016] The lattice constant of the epitaxial layer material is greater than the lattice constant of the second substrate material, and the second region in the second substrate is warped toward the epitaxial layer side;
[0017] At least the second region includes a patterned structure, and per unit area, the surface area of the first region is smaller than the surface area of the second region.
[0018] Optionally, the second substrate includes a second substrate body portion and a second substrate protrusion portion connected to each other, the second substrate protrusion portion being located on the side of the second substrate body portion away from the epitaxial layer, and the coverage area of the second substrate protrusion portion being smaller than the coverage area of the second substrate body portion.
[0019] At least a portion of the second substrate protrusion is located in the second region, and the surface of the second substrate protrusion located in the second region includes the patterned structure.
[0020] Optionally, the first region includes a first region A and a first region B, wherein the first region B is located on the side of the first region A away from the edge;
[0021] The first region A includes a first patterned structure A, and the first region B includes a first patterned structure B; per unit area, the surface area of the first patterned structure A is greater than the surface area of the first patterned structure B.
[0022] or,
[0023] The second region includes a second A region and a second B region, and the second B region is located on a side of the second A region away from the center;
[0024] The second A region includes a second A patterned structure, and the second B region includes a second B patterned structure; in a unit area, the surface area of the second A patterned structure is greater than the surface area of the second B patterned structure.
[0025] Optionally, the patterned structure includes a plurality of basic patterns, and the basic pattern includes a triangle;
[0026] The triangle includes a vertex angle and two base angles, the vertex angle is located on a side of the base angles close to the epitaxial layer, and the vertex angle is less than or equal to 90°.
[0027] Optionally, the triangle includes an isosceles triangle.
[0028] Optionally, the thickness of the substrate is H1, and the etching depth of the patterned structure is H2, where 0 < H2 ≤ H1 / 2.
[0029] In a second aspect, an embodiment of the present invention further provides a semiconductor device, including the epitaxial structure described in the first aspect, and further including an electrode structure located on a side of the epitaxial structure away from the substrate.
[0030] In a third aspect, an embodiment of the present invention further provides a method for preparing an epitaxial structure of a semiconductor device, for preparing the epitaxial structure described in the first aspect; including:
[0031] Providing a substrate, the substrate includes a first surface, and the first surface includes a first region and a second region; the first region at least includes an edge of the first surface, and the second region at least includes a center of the first surface;
[0032] At least preparing a patterned structure in the first region, and in a unit area, the surface area of the first region is greater than the surface area of the second region; or at least preparing a patterned structure in the second region, and in a unit area, the surface area of the first region is less than the surface area of the second region;
[0033] Preparing a multi-layer epitaxial layer on a side of the substrate away from the first surface, and the lattice constant of the epitaxial layer material is different from the lattice constant of the substrate material.
[0034] Optionally, the substrate includes a first substrate, and the lattice constant of the epitaxial layer material is less than the lattice constant of the first substrate material;
[0035] A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including:
[0036] At least in the first region, a patterned structure is prepared;
[0037] Alternatively, the substrate may include a second substrate, wherein the lattice constant of the epitaxial layer material is greater than the lattice constant of the first substrate material;
[0038] A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including:
[0039] A patterned structure is prepared at least in the second region.
[0040] The epitaxial structure of the semiconductor device provided in this invention includes a substrate and an epitaxial layer, wherein the lattice constant of the epitaxial layer material is different from that of the substrate material. The substrate includes a first surface away from the epitaxial layer, the first surface including a first region and a second region, the first region including at least the edge of the first surface, and the second region including at least the center of the first surface. At least the first region includes a patterned structure, and the surface area of the first region per unit area is greater than the surface area of the second region; or, at least the second region includes a patterned structure, and the surface area of the first region per unit area is smaller than the surface area of the second region. By designing a pattern at least in the first region or at least in the second region, the surface area of the substrate in the first region or the second region is increased. By receiving more temperature through the increased surface area, the problem of uneven substrate surface temperature caused by "concave" or "convex" warping during substrate growth is solved or reduced, thereby reducing the unevenness of substrate surface temperature and improving the uniformity of the epitaxial structure. Attached Figure Description
[0041] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0042] Figure 1 This is a schematic diagram of the substrate structure during the epitaxial growth process in the prior art;
[0043] Figure 2 This is a schematic diagram illustrating the relationship between substrate structure and temperature in the prior art;
[0044] Figure 3 This is a schematic diagram of the epitaxial structure of a semiconductor device provided in an embodiment of the present invention;
[0045] Figure 4 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention;
[0046] Figure 5 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention;
[0047] Figure 6 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention;
[0048] Figure 7 This is a schematic diagram of a substrate structure provided in an embodiment of the present invention;
[0049] Figure 8 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention;
[0050] Figure 9 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention;
[0051] Figure 10 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention;
[0052] Figure 11 This is a schematic diagram of the structure of a first region provided in an embodiment of the present invention;
[0053] Figure 12 This is a schematic diagram of the structure of a second region provided in an embodiment of the present invention;
[0054] Figure 13 This is a schematic diagram of the substrate thermal radiation structure provided in an embodiment of the present invention;
[0055] Figure 14 This is a schematic diagram of the structure of a semiconductor device provided in an embodiment of the present invention;
[0056] Figure 15 This is a schematic flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention. Detailed Implementation
[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be fully described below with reference to the accompanying drawings in the embodiments of this invention, through specific implementation methods. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort fall within the protection scope of this invention.
[0058] Figure 3 This is a schematic diagram of the epitaxial structure of a semiconductor device provided in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of the epitaxial structure of another semiconductor device provided in an embodiment of the present invention, combined with... Figures 3-6 As shown, the epitaxial structure 100 of the semiconductor device 10 includes a substrate 110 and a multilayer epitaxial layer 120 located on one side of the substrate.
[0059] Substrate 110 includes a first surface 111 on the side away from epitaxial layer 120. The first surface 111 includes a first region 11A and a second region 111B. The first region 111A includes at least the edge of the first surface 111, and the second region 111B includes at least the center of the first surface 111.
[0060] The lattice constant of the epitaxial layer 120 material is different from that of the substrate 110 material;
[0061] At least the first region 111A includes a patterned structure, and the surface area of the first region 111A per unit area is greater than the surface area of the second region 111B;
[0062] Alternatively, at least the second region 111B includes a patterned structure, and the surface area of the first region 111A per unit area is smaller than the surface area of the second region 111B.
[0063] The main growth methods for semiconductor device epitaxial structures include metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), and liquid phase epitaxy (LPE). Most of these methods require heating the substrate to a certain temperature before epitaxial growth of the semiconductor material, followed by cooling and removal after the growth process is complete. The substrate material is typically sapphire, Si, or SiC. A new crystal is grown on the substrate to form an epitaxial layer, usually made of AlN or GaN. The epitaxial structure 100 of the semiconductor device includes a substrate 110 and multiple epitaxial layers 120 located on one side of the substrate 110.
[0064] The substrate 110 includes a first surface 111 on the side away from the epitaxial layer 120, wherein the first surface 111 is a heated region of the substrate 110. The first surface 111 includes a first region 111A and a second region 111B, wherein the first region 111A includes at least the edge of the first surface 111, and the second region 111B includes at least the center of the first surface 111. Because the substrate 110 and the epitaxial layer 120 are made of different materials, specifically, the materials of the substrate 110 and the epitaxial layer 120 have different lattice constants, the substrate deforms during the growth process due to lattice mismatch, resulting in different degrees of heating for the first region 111A and the second region 111B of the first surface 111. Therefore, embodiments of the present invention creatively provide that at least the first region 111A includes a patterned structure, and the surface area of the first region 111A per unit area is greater than the surface area of the second region 111B; or, at least the second region 111B includes a patterned structure, and the surface area of the first region 111A per unit area is smaller than the surface area of the second region 111B. The patterned structure, compared to a planar structure, increases the surface area of the first surface 111 of the substrate 110, thereby increasing heat absorption. Specifically, refer to... Figure 3 As shown, the first region 111A includes a patterned structure, which can increase the surface area of the first region 111A and increase the heat absorbed. (Reference) Figure 4 As shown, the second region 111B includes a patterned structure, which can increase the surface area of the second region 111B and increase the heat absorbed. (Reference) Figure 5 Both the first region 111A and the second region 111B include patterned structures, and the surface area of the first region 111A per unit area is larger than that of the second region 111B, ensuring that the first region 111A receives more heat than the second region 111B, and ensuring uniform heating in different regions of the substrate. (Reference) Figure 6 Both the first region 111A and the second region 111B include patterned structures. In terms of unit area, the surface area of the first region 111A is smaller than that of the second region 111B, ensuring that the second region 111B receives more heat than the first region 111A, and ensuring that different regions of the substrate are heated evenly.
[0065] Furthermore, in the actual fabrication process, at least a first region 111A or at least a second region 111B can be pre-set to include a patterned structure, depending on the deformation of the substrate.
[0066] In summary, the epitaxial structure provided by the embodiments of the present invention increases the surface area of the first or second region by patterning at least in the first region or at least in the second region. The increased surface area allows for the reception of more heat, ensuring uniform heating in different regions of the substrate. This overcomes the problem of uneven substrate surface temperature caused by substrate warping during growth due to different substrate and epitaxial layer materials, thus ensuring uniform heating in different regions of the substrate and improving the uniformity of the epitaxial structure and semiconductor device.
[0067] As a feasible implementation method, Figure 7 This is a schematic diagram of a substrate structure provided in an embodiment of the present invention, such as... Figure 7 As shown, substrate 110 includes a first substrate 1110;
[0068] The lattice constant of the epitaxial layer 120 material is less than the lattice constant of the first substrate 1110 material, and the first region 111A in the first substrate 1110 warps toward the epitaxial layer 120.
[0069] At least the first region 111A includes a patterned structure, and the surface area of the first region 111A per unit area is greater than the surface area of the second region 111B.
[0070] In this process, the epitaxial growth of semiconductor materials is performed by heating the substrate to a certain temperature on a tray. Multiple circular grooves are distributed on the surface of the tray for placing the substrate. The first substrate 1110, including substrate 110, can be understood as a substrate that undergoes a concave warping deformation during the heating process. Because the lattice constant of the epitaxial layer 120 material is smaller than that of the first substrate 1110 material, the first region 111A in the first substrate 1110 warps towards the epitaxial layer 120, reducing the heat received by the first region 111A. By including at least a patterned structure in the first region 111A, the surface area of the first region 111A is increased, thus increasing the heat received by the first region 111A. Since at least the first region 111A includes a patterned structure, and the surface area of the first region 111A per unit area is larger than that of the second region 111B, the first surface 111 of the first substrate 1110 can be heated more uniformly during the fabrication of the epitaxial structure 100, improving product uniformity.
[0071] For example, taking a substrate 110 made of sapphire and an epitaxial layer 120 made of GaN, the substrate 110 will undergo a concave warping deformation during the growth process. At this time, the first region 111A of the first surface 111 will be reduced in heat due to warping towards the epitaxial layer 120. By at least setting the first region 111A to include a patterned structure, the surface area of the first region 111A can be increased. The increased surface area receives more heat to ensure that different regions of the substrate are heated evenly.
[0072] Based on the above embodiments, Figure 8 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention, with reference to... Figure 8 As shown, the first substrate 1110 includes a first substrate body portion 1111 and a first substrate protrusion portion 1112 that are connected to each other. The first substrate protrusion portion 1112 is located on the side of the first substrate body portion 1111 away from the epitaxial layer 120, and the coverage area of the first substrate protrusion portion 1112 is smaller than the coverage area of the first substrate body portion 1111.
[0073] At least a portion of the first substrate protrusion 1112 is located in the first region 111A, and the surface of the first substrate protrusion 1112 located in the first region 111A includes a patterned structure.
[0074] The first substrate 1110 includes a first substrate body portion 1111 and a first substrate protrusion portion 1112 connected to each other. The first substrate protrusion portion 1112 is located on the side of the first substrate body portion 1111 away from the epitaxial layer 120, and the coverage area of the first substrate protrusion portion 1112 is smaller than the coverage area of the first substrate body portion 1111. The provision of the first substrate protrusion portion 1112 increases the coverage area of the first substrate 1110 in this part, improves the heat absorption efficiency of this part, and ensures the uniformity of the product during epitaxial growth. Meanwhile, at least a portion of the first substrate protrusion 1112 is located in the first region 111A. For example, the first substrate protrusion 1112 may be located only in the first region 111A, meaning that the first substrate protrusion 1112 does not overlap with the second region 111B; or, for example, a larger portion of the first substrate protrusion 1112 is located in the first region 111A, and a smaller portion is located in the second region 111B, ensuring that the arrangement of the first substrate protrusion 1112 can increase the coverage area of the first region 111A, thereby increasing the heat received by the first region 111A. Furthermore, the surface of the first substrate protrusion 1112 located in the first region 111A includes a patterned structure. Setting the patterned structure increases the bottom surface area, thus increasing the heat received.
[0075] As another feasible implementation method Figure 9 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention. In the fabrication process of the epitaxial structure 100, the substrate 110 includes a second substrate 1120.
[0076] The lattice constant of the epitaxial layer 120 material is greater than the lattice constant of the second substrate 1120 material, and the second region 111B in the second substrate 1120 is warped toward the epitaxial layer 120 side;
[0077] At least the second region 111A includes a patterned structure, and the surface area of the first region 111A per unit area is smaller than the surface area of the second region 111B.
[0078] The substrate 110 includes a second substrate 1120, which can be understood as a substrate that undergoes a convex warping deformation during the heating process. Because the lattice constant of the epitaxial layer 120 material is greater than that of the second substrate 1120 material, the second region 111B in the second substrate 1120 warps towards the epitaxial layer 120, reducing the heat received by the second region 111B. By including at least a patterned structure in the second region 111B, the surface area of the second region 111B is increased, thus increasing the heat received by the second region 111B. At least the second region 111A includes a patterned structure, and the surface area per unit area of the first region 111A is smaller than that of the second region 111B. This ensures uniform heating of the first surface 111 of the second substrate 1120 during the fabrication of the epitaxial structure 100, improving product uniformity.
[0079] For example, taking a substrate 110 made of SiN and an epitaxial layer 120 made of GaN, the substrate 110 will undergo a "convex" warping deformation during the growth process. At this time, the second region 111B of the first surface 111 will be reduced in heat due to warping towards the epitaxial layer 120. By setting the second region 111B to include a patterned structure, the surface area of the second region 111B can be increased. The increased surface area receives more heat to ensure that different regions of the substrate are heated evenly.
[0080] Based on the above embodiments, Figure 10 This is a schematic diagram of another substrate structure provided in an embodiment of the present invention, with reference to... Figure 10 As shown, the second substrate 1120 includes a second substrate body portion 1121 and a second substrate protrusion portion 1122 that are connected to each other. The second substrate protrusion portion 1122 is located on the side of the second substrate body portion 1121 that is close to the side away from the epitaxial layer 120, and the coverage area of the second substrate protrusion portion 1122 is smaller than the coverage area of the second substrate body portion 1121.
[0081] At least a portion of the second substrate protrusion 1122 is located in the second region 111B, and the surface of the second substrate protrusion 1122 located in the second region 111B includes the patterned structure.
[0082] The second substrate 1120 includes a second substrate body portion 1121 and a second substrate protrusion portion 1122 that are connected to each other. The second substrate protrusion portion 1122 is located on the side of the second substrate body portion 1121 away from the epitaxial layer 120, and the coverage area of the second substrate protrusion portion 1122 is smaller than the area of the second substrate body portion 1121. The provision of the second substrate protrusion portion 1122 increases the coverage area of the second substrate 1120 in this part, improves the heat absorption efficiency of this part, and ensures the uniformity of the product during epitaxial growth. Meanwhile, at least a portion of the second substrate protrusion 1122 is located in the first region 111B. For example, the second substrate protrusion 1122 may be located only in the second region 111B, meaning that the second substrate protrusion 1122 does not overlap with the first region 111A; or, for example, a larger portion of the second substrate protrusion 1122 is located in the second region 111B, and a smaller portion is located in the first region 111A, ensuring that the arrangement of the second substrate protrusion 1122 can increase the coverage area of the second region 111B, thereby increasing the heat received by the second region 111B. Furthermore, the surface of the second substrate protrusion 1122 located in the second region 111B includes a patterned structure. The patterned structure increases the bottom surface area, thus increasing the heat received.
[0083] Furthermore, Figure 11 This is a schematic diagram of the structure of a first region provided in an embodiment of the present invention. Figure 12 This is a schematic diagram of the structure of a second region provided in an embodiment of the present invention, such as... Figure 11 As shown, the first region 111A includes a first region A 111A1 and a first region B 111A2, with the first region B 111A2 located on the side of the first region A 111A1 away from the edge;
[0084] Region A 111A1 includes a patterned structure A, and Region B 111A2 includes a patterned structure B; per unit area, the surface area of the patterned structure A is greater than the surface area of the patterned structure B.
[0085] or,
[0086] like Figure 12 As shown, the second region 111B includes the second region A 111B1 and the second region B 111B2, with the second region B 111B2 located on the side of the second region A 111B1 away from the center.
[0087] Region A 111B1 includes patterned structure A, and region B 111B2 includes patterned structure B; per unit area, the surface area of patterned structure A is greater than the surface area of patterned structure B.
[0088] The substrate 110 includes a first surface 111, which includes a first region 111A and a second region 111B. The first region 112 includes a first region A 111A1 and a first region B 111A2, with the first region B 111A2 located on the side of the first region A 111A1 away from the edge. Under the concave warping deformation, the first region A 111A1 is farther from the support tray 20 than the first region B 111A2, and can receive relatively less heat. Therefore, the surface area of the first patterned structure in the first region A 111A1 is set larger than the surface area of the first patterned structure in the first region B 111A2 per unit area. By further adjusting the patterned structure in the first region A 111A, it can be ensured that the heat received by different regions in the first region A 111A is the same or similar, further improving the structural uniformity in the first region A 111A.
[0089] Furthermore, the surface area of the first patterned structure A per unit area is greater than that of the first patterned structure B. This can be achieved through various different configurations, and two feasible configurations are illustrated below. When the first patterned structure A and the first patterned structure B have the same patterned structure, the first region A 111A1 located at the edge of the first region A and the first region B 111A2 located at the sub-edge are configured with patterns of different densities, so that the pattern density of the first region A 111A1 is higher than that of the first region B 111A2. When the first region A 111A1 receives less heat than the first region B 111A2, the heat received by the first region A 111A1 is increased by increasing the pattern density. When the first patterned structure A and the first patterned structure B have different patterned structures, that is, when the basic patterned shapes are different, the surface area of the basic pattern in the patterned structure set in the first region A 111A1 that can receive thermal radiation is greater than that of the basic pattern in the patterned structure set in the first region B 111A2. For example, the basic pattern in the patterned structure set in the first region A 111A1 is a triangle, and the basic pattern in the patterned structure set in the first region B 111A2 is a rectangle.
[0090] Furthermore, the second region 111B includes a second region A 111B1 and a second region B 111B2, with region B 111B2 located on the side of second region A 111B1 furthest from the center. Under the convex warping deformation, region A 111B1 is farther from the bearing tray 20 than region B 111B2, and therefore receives relatively less heat. Thus, the surface area of the second patterned structure in region A 111B1 is larger than the surface area of the second patterned structure in region B 111B2 per unit area. By further adjusting the patterned structure in region 111B, it can be ensured that different regions in region 111B receive the same or similar amounts of heat, further improving the structural uniformity of region 111B.
[0091] Furthermore, the surface area of the second patterned structure A per unit area is greater than that of the second patterned structure B. This can be achieved through various different configurations, two of which are illustrated below. When the second patterned structure A and the second patterned structure B have the same patterned structure, the second region A 111B1 located at the edge of the second region 111B and the second region B 111B2 located at the sub-edge are configured with patterns of different densities, such that the pattern density of the second region A 111B1 is higher than that of the second region B 111B2. To ensure that the second region A 111B1 receives less heat than the second region B 111B2, the heat received by the second region A 111B1 is increased by increasing the pattern density. When the second patterned structure A and the second patterned structure B have different patterned structures, that is, when the basic patterned shapes are different, the surface area of the basic pattern in the patterned structure set in the second region A 111B1 that can receive thermal radiation is greater than that of the basic pattern in the patterned structure set in the second region B 111B2. For example, the basic pattern in the patterned structure set in the second region A 111B1 is a triangle, and the basic pattern in the patterned structure set in the second region B 111B2 is a rectangle.
[0092] By performing different patterning designs on the first region 111A1 and the first region 111A2 (including the first region A 111A1 and the first region B 111A2) and the second region 111B1 (including the second region A 111B1 and the second region B 111B2), the uneven heating of the bottom of the substrate caused by substrate warping is more effectively alleviated during the epitaxial growth process of the substrate 110 in the support tray 20, thereby improving the uniformity of the semiconductor device.
[0093] Figure 13 This is a schematic diagram of the substrate thermal radiation structure provided in an embodiment of the present invention, combined with... Figures 3-13 As shown, the patterned structure includes multiple basic patterns, including triangles;
[0094] The triangle includes a vertex angle A and two base angles B and C. The vertex angle A is located on the side of the base angles B and C close to the epitaxial layer 100, and the vertex angle is less than or equal to 90°.
[0095] Among them, the patterned structures included in the first region 111A and the second region 111B in the first surface 111 may have multiple basic patterns, and the basic patterns include triangles. When the basic pattern is a triangle, the vertex angle A included in the triangle is close to the epitaxial layer 100, and the base angles B and C are far from the epitaxial layer 100 and close to the carrier tray 20. Refer to Figure 13 , when the degree of the vertex angle A is less than or equal to 90°, while increasing the surface area of the first surface 111 of the substrate 110, the reflection of thermal radiation is reduced. As Figure 13 shown, the dotted line represents thermal radiation. After multiple reflections of the thermal radiation, the thermal radiation is finally reflected onto the substrate 110 instead of other places, ensuring uniform heating of the first surface 111. Therefore, under the same heater power, this shape can absorb more radiation compared to other shapes, thereby improving the temperature uniformity of the surface of the substrate 110 in the case where the substrate 110 is warped.
[0096] Optionally, the triangle includes an isosceles triangle.
[0097] Among them, the triangle can include an isosceles triangle. The degree of the vertex angle A of the isosceles triangle satisfies less than or equal to 90°. At the same time, the preparation process of the isosceles triangle is simple and convenient, which is beneficial to the design and production of the substrate structure.
[0098] Continue to refer to Figure 6 shown. Optionally, the thickness of the substrate 110 is H1, and the etching depth of the patterned structure is H2, where 0 < H2 ≤ H1 / 2.
[0099] Among them, the etching depth H2 of the patterned structure is less than the thickness of the substrate 110 to prevent the substrate from being etched through during the patterned etching process. Specifically, 0 < H2 ≤ H1 / 2, that is, the etching depth H2 of the patterned structure is less than half of the thickness of the substrate 110, ensuring that the influence on the substrate during the etching process of the patterned structure is small. While ensuring an increase in the surface area of the first surface 111, the stability of the substrate structure is ensured, and further the stability of the epitaxial structure and the semiconductor device structure is ensured.
[0100] Based on the same inventive concept, the embodiments of the present invention also provide a semiconductor device. The semiconductor device provided by the embodiments of the present invention includes the epitaxial structure of the semiconductor device described in the above embodiments. Further, Figure 14 is a schematic structural diagram of a semiconductor device provided by an embodiment of the present invention. As Figure 14 shown, the semiconductor device provided by the embodiments of the present invention further includes an electrode structure 130 on the side of the epitaxial structure 100 away from the substrate 110.
[0101] in, Figure 14 Taking a patterned structure in the first region as an example, the epitaxial layer 120 of the semiconductor device epitaxial structure 100 includes a nucleation layer 121, a buffer layer 122, a channel layer 123, and a barrier layer 124. Figure 12 As shown, a nucleation layer 121 is located on the substrate 110; a buffer layer 122 is located on the side of the nucleation layer 121 away from the substrate 110; a channel layer 123 is located on the side of the buffer layer 122 away from the nucleation layer 121; and a barrier layer 124 is located on the side of the channel layer 123 away from the buffer layer 122. The barrier layer 124 and the channel layer 123 form a heterojunction structure, and a 2DEG is formed at the heterojunction interface.
[0102] For example, the materials of nucleation layer 121 and buffer layer 122 can be nitrides, specifically GaN, AlN, or other nitrides. Nucleation layer 121 and buffer layer 122 can be used to match the material of substrate 110 and epitaxial channel layer 123. The material of channel layer 123 can be GaN or other semiconductor materials, such as InAlN. Barrier layer 124 is located above channel layer 123. The material of barrier layer 124 can be any semiconductor material capable of forming a heterojunction structure with channel layer 123, including gallium compound semiconductor materials or nitride semiconductor materials, such as InxAlyGazN1-xyz, where 0≤x≤1, 0≤y≤1, and 0≤z≤1. Optionally, channel layer 123 and barrier layer 124 form a semiconductor heterojunction structure, forming a high-concentration two-dimensional electron gas at the interface between channel layer 123 and barrier layer 124.
[0103] The semiconductor device also includes an electrode structure 130 on the side of the epitaxial structure 100 away from the substrate 110. The electrode structure 130 includes a source 131, a gate 132, and a drain 133, wherein the source 131 and drain 133 are located on the side of the barrier layer 124 away from the substrate 110, and the gate 132 is located between the source 131 and drain 133. For example, the source 131 and drain 132 are located on the side of the barrier layer 124 away from the substrate 110, and the source 131 and drain 133 respectively form ohmic contacts with the barrier layer 124; the gate 132 is located between the source 131 and drain 133, and is also located on the side away from the substrate 110.
[0104] It should be understood that the embodiments of the present invention ensure that the bottom of the substrate is heated uniformly and the semiconductor device product has good uniformity from the perspective of substrate structure design of semiconductor devices. Semiconductor devices include, but are not limited to: high-power gallium nitride high electron mobility transistors (HEMTs) operating under high voltage and high current conditions; silicon-on-insulator (SOI) transistors; gallium arsenide (GaAs)-based transistors; and metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-insulator-semiconductor field-effect transistors (MISFETs), double heterojunction field-effect transistors (DHFETs), junction field-effect transistors (JFETs), metal-semiconductor field-effect transistors (MESFETs), and metal-insulator-semiconductor heterojunction field-effect transistors (MESFETs). Transistor (MISHFET) or other field-effect transistors.
[0105] This invention also provides a method for fabricating the epitaxial structure of a semiconductor device. Figure 13 This is a schematic flowchart of a method for fabricating an epitaxial structure of a semiconductor device according to an embodiment of the present invention, as shown below. Figure 13 As shown, the method for fabricating the epitaxial structure of a semiconductor device provided in this embodiment of the invention may include:
[0106] S110. A substrate is provided, the substrate including a first surface, the first surface including a first region and a second region; the first region includes at least the edge of the first surface, and the second region includes at least the center of the first surface.
[0107] For example, the substrate material can be one or more combinations of gallium nitride, aluminum gallium nitride, indium gallium nitride, aluminum indium gallium nitride, indium phosphide, gallium arsenide, silicon carbide, diamond, sapphire, germanium, and silicon. The substrate can be prepared by atmospheric pressure chemical vapor deposition, sub-atmospheric pressure chemical vapor deposition, metal-organic chemical vapor deposition, low-pressure chemical vapor deposition, high-density plasma chemical vapor deposition, etc. The prepared substrate includes a first surface. The first surface includes a first region and a second region; the first region includes at least the edge of the first surface, and the second region includes at least the center of the first surface.
[0108] S120. At least a patterned structure is prepared in the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, at least a patterned structure is prepared in the second region, and the surface area of the first region per unit area is less than the surface area of the second region.
[0109] For example, when the substrate is to undergo a concave warpage, the first region warps towards the epitaxial layer. A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than that of the second region, increasing the surface area of the first region and thus increasing heat absorption. Similarly, when the substrate is to undergo a convex warpage, the second region warps towards the epitaxial layer. A patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is smaller than that of the second region. This ensures that the warped portion is patterned, increasing the heat-receiving area.
[0110] S130. A multilayer epitaxial layer is prepared on the side of the substrate away from the first surface, wherein the lattice constant of the epitaxial layer material is different from the lattice constant of the substrate material.
[0111] The epitaxial layer is grown using methods such as metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), and liquid phase epitaxy (LPE), and is grown on a substrate. The epitaxial layer includes a nucleation layer, a buffer layer, a channel layer, and a barrier layer, which are sequentially disposed on one side of the substrate.
[0112] In summary, this invention increases the surface area of the first or second region of the substrate by patterning the first or second region, ensuring that the first or second region can receive more heat and that different regions of the substrate are heated uniformly. This overcomes the problem of uneven substrate surface temperature caused by substrate warping during growth due to different substrate and epitaxial layer materials and lattice constants, thereby improving the uniformity of epitaxial structures and semiconductor devices.
[0113] Optionally, the substrate includes a first substrate, wherein the lattice constant of the epitaxial layer material is smaller than the lattice constant of the first substrate material;
[0114] A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including:
[0115] At least in the first region, a patterned structure is prepared;
[0116] Alternatively, the substrate may include a second substrate, wherein the lattice constant of the epitaxial layer material is greater than the lattice constant of the first substrate material;
[0117] A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including:
[0118] A patterned structure is prepared at least in the second region.
[0119] In this process, substrates made of different materials exhibit warping deformations (either concave or convex) during epitaxial growth. By fabricating a patterned structure on the first surface of the substrate, the thermal contact area of the warped portions is increased, resulting in uniformity in the manufactured semiconductor devices. Specifically, the substrate includes a first substrate. When the lattice constant of the epitaxial layer material is less than that of the first substrate material, a patterned structure is fabricated in at least a first region, ensuring that the surface area of the first region is greater than that of the second region. Alternatively, the substrate includes a second substrate. When the lattice constant of the epitaxial layer material is greater than that of the first substrate material, a patterned structure is fabricated in at least a second region, ensuring that the surface area of the first region is less than that of the second region. Another option is to fabricate a patterned structure in the first region, ensuring that the surface area of the first region is less than that of the second region.
[0120] For example, depending on the material type of the first substrate and the material type of the epitaxial layer, during the epitaxial layer growth process, the substrate undergoes concave or convex deformation to fabricate a patterned structure in the first or second region of the first surface, increasing the contact area away from the support tray. This ensures uniform heating of the substrate during the fabrication of the epitaxial structure of the semiconductor device.
[0121] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Features of various embodiments of the present invention can be partially or wholly coupled or combined with each other, and can cooperate and be technically driven in various ways. Various obvious changes, readjustments, combinations, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. An epitaxial structure for a semiconductor device, characterized in that, Includes a substrate and a multilayer epitaxial layer located on one side of the substrate; The substrate includes a first surface on the side away from the epitaxial layer, the first surface including a first region and a second region, the first region including at least the edge of the first surface, and the second region including at least the center of the first surface; The lattice constant of the epitaxial layer material is different from that of the substrate material; At least the first region includes a patterned structure, and per unit area, the surface area of the first region is greater than the surface area of the second region; Alternatively, at least the second region includes a patterned structure, and the surface area of the first region is smaller than the surface area of the second region per unit area; The substrate includes a first substrate; The lattice constant of the epitaxial layer material is less than the lattice constant of the first substrate material, and the first region in the first substrate is warped toward the epitaxial layer side; At least the first region includes a patterned structure, and per unit area, the surface area of the first region is greater than the surface area of the second region; Alternatively, the substrate may include a second substrate; The lattice constant of the epitaxial layer material is greater than the lattice constant of the second substrate material, and the second region in the second substrate is warped toward the epitaxial layer side; At least the second region includes a patterned structure, and per unit area, the surface area of the first region is smaller than the surface area of the second region.
2. The epitaxial structure according to claim 1, characterized in that, The first substrate includes a first substrate body portion and a first substrate protrusion portion connected to each other. The first substrate protrusion portion is located on the side of the first substrate body portion away from the epitaxial layer, and the coverage area of the first substrate protrusion portion is smaller than the coverage area of the first substrate body portion. At least a portion of the first substrate protrusion is located in the first region, and the surface of the first substrate protrusion located in the first region includes the patterned structure.
3. The epitaxial structure according to claim 1, characterized in that, The second substrate includes a second substrate body portion and a second substrate protrusion portion that are interconnected. The second substrate protrusion portion is located on the side of the second substrate body portion away from the epitaxial layer, and the coverage area of the second substrate protrusion portion is smaller than the coverage area of the substrate body portion. At least a portion of the second substrate protrusion is located in the second region, and the surface of the second substrate protrusion located in the second region includes the patterned structure.
4. The epitaxial structure according to claim 1, characterized in that, The first region includes a first region A and a first region B, wherein the first region B is located on the side of the first region A away from the edge; The first region A includes a first patterned structure A, and the first region B includes a first patterned structure B; per unit area, the surface area of the first patterned structure A is greater than the surface area of the first patterned structure B. or, The second region includes a second region A and a second region B, with the second region B located on the side of the second region A away from the center; The second region A includes a second patterned structure A, and the second region B includes a second patterned structure B; per unit area, the surface area of the second patterned structure A is greater than the surface area of the second patterned structure B.
5. The epitaxial structure according to claim 1, characterized in that, The patterned structure includes multiple basic patterns, including triangles; The triangle includes a vertex angle and two base angles, the vertex angle being located on the side of the base angles closest to the epitaxial layer, and the vertex angle being less than or equal to 90°.
6. The extensional structure according to claim 5, further characterized in that the triangle comprises an isosceles triangle.
7. The epitaxial structure according to claim 1, characterized in that, The thickness of the substrate is H1, and the etching depth of the patterned structure is H2, wherein 0 <H2≤H1 / 2。 8. A semiconductor device, characterized in that, The epitaxial structure includes the epitaxial structure according to any one of claims 1-7, and further includes an electrode structure located on the side of the epitaxial structure away from the substrate.
9. A method for fabricating an epitaxial structure of a semiconductor device, used to fabricate the epitaxial structure according to any one of claims 1-7; characterized in that, include: A substrate is provided, the substrate including a first surface, the first surface including a first region and a second region; the first region includes at least an edge of the first surface, and the second region includes at least a center of the first surface; A patterned structure is prepared in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is prepared in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region. A multilayer epitaxial layer is prepared on the side of the substrate away from the first surface, wherein the lattice constant of the epitaxial layer material is different from that of the substrate material; Wherein, the substrate includes a first substrate, and the lattice constant of the epitaxial layer material is smaller than the lattice constant of the first substrate material; A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including: At least a patterned structure is prepared in the first region; Alternatively, the substrate may include a second substrate, wherein the lattice constant of the epitaxial layer material is greater than the lattice constant of the first substrate material; A patterned structure is fabricated in at least the first region, and the surface area of the first region per unit area is greater than the surface area of the second region; or, a patterned structure is fabricated in at least the second region, and the surface area of the first region per unit area is less than the surface area of the second region, including: A patterned structure is prepared at least in the second region.