Epitaxial wafer and long-wave emission optoelectronic device
By using the set of a boss structure and a nanoporous silicon nitride cover layer on the substrate in the GaN-based semiconductor material epitaxial sheet, the dislocation and stress problems caused by heterogeneous substrates are solved, the luminous efficiency and brightness are improved, and the The leakage performance of LED has promoted the application of LED in the field of high-end lighting display.
Patent Information
- Application Number
- CN202420748783.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2034-04-11
AI Technical Summary
When the GaN-based semiconductor material epitaxial sheet grows on a heterogeneous substrate, it has high dislocation density and high stress due to the mismatch between the lattice and thermal expansion, which affects the efficiency and life of the device, and has low luminous intensity and efficiency, which limits LEDs in high-end lighting display. Application in the field.
A long-wave emitting optoelectronic device epitaxial sheet is designed, adopting a multi-spaced boss structure on the substrate main body, and a silicon nitride cover layer with a silicon oxide filled structure and a nanopore structure to alleviate nitride buffering The tensile stress in the layer improves the crystal quality and component uniformity of the luminescent layer, and reduces non-radiative recombination and leakage current.
By introducing compressive stress and microporous structure, the crystal quality and luminous efficiency of the luminescent layer are improved, the defect distribution caused by high stress is reduced, the brightness and leakage performance of the LED are enhanced, and the working efficiency and life of the device are improved.
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Figure CN222126568U_ABST
Abstract
Description
Technical Field
[0001] The utility model particularly relates to an epitaxial wafer and a long-wave emission optoelectronic device, belonging to the technical field of optoelectronic semiconductor devices. Background Art
[0002] GaN-based light-emitting diodes (LEDs) have the advantages of long life, low energy consumption, small size, and high reliability. They have become the most promising lighting source and an important trend in leading lighting technology. However, there are still problems with low luminous intensity and efficiency. Further improving the luminous intensity and light efficiency of LEDs is the goal of the development of LED lighting technology.
[0003] At present, GaN-based semiconductor material MOCVD epitaxy is an epitaxial growth technology on heterogeneous substrates. Due to the lattice and thermal expansion mismatch between the substrate and the epitaxial layer, the epitaxially grown crystal material has a high dislocation density and high stress. These dislocations appear as non-radiative recombination centers when the device is working and affect the device efficiency. At the same time, they cause the leakage current to increase and the device to age rapidly, affecting the working efficiency and life of the device, which restricts the application of LED high-end lighting display field.
[0004] The currently widely used substrate patterning technology can improve the light extraction efficiency. Therefore, how to use the patterned substrate technology to further improve the light extraction efficiency of LEDs has become a hot topic in industry research and is of great significance to the market promotion and application of LEDs. Utility Model Content
[0005] The main purpose of the utility model is to provide an epitaxial wafer and a long-wave emission optoelectronic device, thereby overcoming the deficiencies in the prior art.
[0006] In order to achieve the above-mentioned utility model purpose, the technical solution adopted by the utility model includes:
[0007] On the one hand, the utility model provides a long-wave emission optoelectronic device epitaxial wafer, comprising:
[0008] A substrate body, wherein a selected surface of the substrate body has a plurality of spaced-apart boss structures;
[0009] A filling structure layer, comprising a plurality of first filling structures, wherein the first filling structures are correspondingly arranged on the top end surface of the boss structure;
[0010] A covering structure layer is continuously covered on the substrate body and the filling structure layer, and the covering structure layer also has a plurality of microporous structures;
[0011] The epitaxial structure layer includes a buffer layer, a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in sequence on the cover structure layer. Part of the buffer layer is also extended in the microporous structure and contacts the substrate body and the filling structure layer.
[0012] Furthermore, a first peripheral side surface of the boss structure and a corresponding second peripheral side surface of the first filling structure are located in the same extension plane.
[0013] Furthermore, the boss structure may be a prism structure, a prism structure, a cylindrical structure, a truncated cone structure, a hemispherical structure, etc.
[0014] Furthermore, the first filling structure may be a pyramid structure, a cone structure, a spherical structure, etc.
[0015] Furthermore, the radial width of the boss structure is 0.5-2 μm.
[0016] Furthermore, the axial height of the boss structure is 0.1-0.5 μm.
[0017] Furthermore, the distance between two adjacent boss structures is 0.1-1 μm.
[0018] Furthermore, the plurality of boss structures are distributed in an array.
[0019] Furthermore, the radial cross-sectional area of the boss structure gradually decreases in a direction away from the selected surface.
[0020] Furthermore, a radial cross-sectional area of the first filling structure gradually decreases in a direction away from the selected surface.
[0021] Furthermore, the axial height of the first filling structure is 0.1-0.5 μm.
[0022] Furthermore, the selected surface of the substrate body also has a plurality of groove-like structures, and the filling structure layer also includes a second filling structure, and the second filling structure is correspondingly arranged in the groove-like structure.
[0023] Furthermore, a top end surface of the second filling structure is flush with or lower than a selected surface of the substrate body.
[0024] Furthermore, the radial width of the groove-like structure is 0.5-2 μm.
[0025] Furthermore, the depth of the groove structure is 0.1-0.5 μm.
[0026] Furthermore, the area of the radial cross section of the groove-like structure gradually decreases in a direction away from the selected surface.
[0027] Furthermore, a radial cross-sectional area of the second filling structure gradually decreases in a direction away from the selected surface.
[0028] Furthermore, the axial height of the second filling structure is 0.1-0.5 μm.
[0029] Furthermore, the covering structure layer has a contoured structure that is similar to the boss structure and the first filling structure as a whole.
[0030] Furthermore, the thickness of the covering structure layer is uniform.
[0031] Furthermore, the thickness of the covering structure layer is 5-50 nm.
[0032] Furthermore, the pore size of the microporous structure is 5 to 100 nm.
[0033] Furthermore, the surface of the buffer layer facing away from the covering structure layer is continuous and flat.
[0034] Furthermore, the buffer layer is a group III nitride buffer layer.
[0035] Furthermore, the substrate body may be a sapphire substrate, a silicon substrate, a silicon carbide substrate, a diamond substrate, a gallium oxide substrate or other nitride substrates.
[0036] Furthermore, one of the first semiconductor layer and the second semiconductor layer is a p-type semiconductor layer, and the other is an n-type semiconductor layer.
[0037] The utility model also provides a long-wave emission optoelectronic device epitaxial wafer, comprising the long-wave emission optoelectronic device epitaxial wafer and an electrode matched with the long-wave emission optoelectronic device epitaxial wafer.
[0038] Compared with the prior art, the advantages of the utility model include:
[0039] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, in which a silicon oxide filling structure is arranged on a protruding structure on a substrate body, and a silicon nitride covering structure layer with nanopores is covered, and the silicon oxide filling layer structure layer enhances the total reflection of the light emitted from the light-emitting layer toward the substrate before reaching the substrate interface, thereby improving the forward light emission of the LED epitaxial wafer;
[0040] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, in which a silicon nitride covering structure layer is introduced on the filling structure layer, and the lattice constant of the silicon nitride is smaller than the lattice constant of the silicon oxide constituting the filling structure layer. Based on this, compressive stress is introduced into the epitaxial wafer, the tensile stress in the nitride buffer layer is relieved, the crystal quality and thickness uniformity of the nitride buffer layer are improved, and a high-quality light-emitting layer growth template is provided, and the stress in the light-emitting layer is reduced;
[0041] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, which improves the crystal quality and component uniformity of the light-emitting layer, reduces the non-radiative recombination caused by defects in the light-emitting layer, and especially for long-wave emission, the low-stress light-emitting layer can improve the incorporation of components in the light-emitting layer, reduces the high defect distribution caused by high stress, improves the brightness of the epitaxial wafer and improves the leakage problem;
[0042] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, in which the silicon nitride covering structure layer utilizes its own nanoporous structure to strengthen the lateral epitaxy between the group III nitride buffer layers, and dislocations turn above the nanoscale microporous structure during the growth process, blocking the dislocations from extending upward into the nitride light-emitting layer, further improving the crystal quality of the nitride material, improving the light-emitting efficiency of the epitaxial wafer, and improving the leakage performance of the epitaxial wafer. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0044] Figure 1 This is a schematic structural diagram of a long-wave emission optoelectronic device epitaxial wafer provided in Example 1 of the utility model;
[0045] Figure 2 It is a schematic structural diagram of another long-wave emission optoelectronic device epitaxial wafer provided in Example 2 of the utility model. DETAILED DESCRIPTION
[0046] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the utility model after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.
[0047] Example 1
[0048] See also Figure 1 , a long-wave emission optoelectronic device epitaxial wafer, comprising:
[0049] A substrate body 10, wherein a selected surface of the substrate body 10 has a plurality of spaced-apart boss structures 11;
[0050] The filling structure layer 20 includes a plurality of first filling structures 21, each of the first filling structures 21 being correspondingly arranged on the top end surface of one of the boss structures 11;
[0051] A covering structure layer 30 is continuously covered on the substrate body 10 and the filling structure layer 20, and the covering structure layer 30 also has a plurality of microporous structures 31;
[0052] The epitaxial structure layer 40 includes a buffer layer 41, an n-type semiconductor layer 42, a light-emitting layer 43 and a p-type semiconductor layer 44 stacked in sequence on the covering structure layer 30. The buffer layer 41 is covered on the covering structure layer 30, and a part of the buffer layer 41 is also extended into the microporous structure and in contact with the substrate body 10 and the filling structure layer 20.
[0053] Specifically, the substrate body 10 may be a sapphire substrate, a silicon substrate, a silicon carbide substrate, a diamond substrate, a gallium oxide substrate or other nitride substrates.
[0054] Specifically, the boss structure 11 is integrated with the substrate body 10, and the radial cross-sectional area of the boss structure 11 gradually decreases in the direction away from the selected surface. More specifically, the boss structure 11 can be a prism structure, a prism structure, a cylindrical structure, a truncated cone structure, a hemispherical structure or a spherical structure, etc. More specifically, the radial width of the boss structure 11 is 0.5 to 2 μm, and the axial height of the boss structure 11 is 0.1 to 0.5 μm. It should be noted that the axial direction of the boss structure 11 is parallel to the thickness direction of the substrate body, and the radial direction of the boss structure 11 is perpendicular to its axial direction.
[0055] Specifically, the plurality of boss structures 11 may be distributed in an array. More specifically, the interval between two adjacent boss structures 11 is 0.1-1 μm.
[0056] Specifically, the boss structure 11 has a top end face and a bottom end face that are opposite to each other along its own axial direction, and its bottom end face is integrated with the selected surface of the substrate body 10, and the first filling structure 21 is stacked on the top end face of the boss structure 11, and the bottom end face of the first filling structure 21 has the same contour shape and area as the top end face of the boss structure 11, and the radial cross-sectional area of the first filling structure 21 gradually decreases in the direction away from the selected surface. It should be noted that, as mentioned above, the boss structure 11 is integrated with the substrate body 10, so the bottom end face of the boss structure is defined here only for better description in order to understand the structure of the boss structure.
[0057] Specifically, the first peripheral side surface of the boss structure 11 and the corresponding second peripheral side surface of the first filling structure 21 are located in the same extension plane. Accordingly, the first filling structure 21 can be a pyramid structure, a cone structure, a spherical structure, etc.
[0058] Specifically, the axial height of the first filling structure 21 is 0.1-0.5 μm.
[0059] Specifically, the first filling structure 21 may be a silicon oxide structure or the like.
[0060] Specifically, under the condition of a certain width of the boss structure, the height of the boss structure and the filling structure needs to match the thickness of the group III nitride buffer layer. As the thickness of the boss structure and the filling structure increases, a thicker group III nitride buffer layer needs to be matched. On the basis of the increase in the height of the boss structure and the thickness of the group III nitride buffer layer, the LED epitaxial wafer has better optoelectronic properties (luminous efficiency and leakage performance). When the height of the boss structure and the filling structure adopts a minimum value, the thickness of the corresponding group III nitride buffer layer has a minimum value. If the height of the boss structure and the filling structure is too small, the effect on the lateral epitaxial growth of the group III nitride buffer layer is not obvious. When the thickness of the group III nitride buffer layer continues to increase, the luminous efficiency and leakage performance of the LED epitaxial wafer do not change much. When the height of the boss structure and the filling structure adopts a maximum value, the thickness of the corresponding group III nitride buffer layer has a maximum value. If the height of the boss structure and the filling structure is too small, the lateral epitaxial dislocations of the III-nitride buffer layer will not have time to turn, resulting in the dislocations being distributed on the surface of the III-nitride buffer layer. When the thickness of the buffer layer continues to increase, there will be little change in the improvement of the luminous efficiency of the LED epitaxial wafer and the improvement of the leakage problem.
[0061] Specifically, the covering structure layer 30 continuously covers the selected surface of the substrate body 10, the surface of the boss structure 11, and the surface of the first filling structure 21, and has a contoured structure similar to the substrate body 10, the boss structure 11 and the first filling structure 21 as a whole. It can be understood that the surface of the covering structure layer 30 is uneven.
[0062] Specifically, the thickness of the covering structure layer 30 is uniform. More specifically, the thickness of the covering structure layer 30 is 5-50 nm.
[0063] Specifically, the covering structure layer 30 is a silicon nitride layer with a microporous structure, and the multiple microporous structures 31 contained therein can be evenly distributed. The microporous structures 31 extend along the thickness direction of the covering structure layer 30 , wherein the pore diameter of the microporous structures 31 is 5 to 100 nm.
[0064] Specifically, the buffer layer 41 , the n-type semiconductor layer 42 , the light emitting layer 43 and the p-type semiconductor layer 44 are all group III nitride layers.
[0065] Specifically, the buffer layer 41 may be a GaN buffer layer, etc. The surface of the buffer layer 41 facing away from the cover structure layer 30 is continuous and flat, and the thickness of the buffer layer 41 is 1-5 μm. Specifically, the n-type semiconductor layer 42 may be an n-type Al x Ga 1-x N layer, 0≤x≤1, the n-type semiconductor layer 42 may be Si-doped, and the Si doping concentration of the n-type semiconductor layer 42 is 1×10 18 cm -3 ~8×10 18 cm -3 Specifically, the thickness of the n-type semiconductor layer 42 is 2 to 10 μm. Specifically, the light-emitting layer 43 may include 2 to 10 periodic cycles of overlapping growth of a quantum well layer with a thickness of 1 to 6 nm and a quantum barrier layer with a thickness of 6 to 25 nm; the quantum well layer and the quantum barrier layer are both III-group nitride structure layers, and illustratively, the quantum well layer may be a GaN well layer, an InGaN well layer, or an AlGaN well layer, and the quantum barrier layer may be a GaN barrier layer, an InGaN barrier layer, or an AlGaN barrier layer. Specifically, the p-type semiconductor layer 44 may be a p-type Al y Ga 1-y N layer, 0≤y≤1, the p-type semiconductor layer 44 may be Mg-doped, and the Mg doping concentration of the p-type semiconductor layer 44 is 1×10 19 cm -3 ~1×10 21 cm -3 Specifically, the thickness of the p-type semiconductor layer 44 is 20 to 300 nm.
[0066] Example 2
[0067] See also Figure 2 The structure of a long-wave emitting optoelectronic device epitaxial wafer in this embodiment is basically the same as that in Embodiment 1, and the same parts of the two will not be repeated here.
[0068] Specifically, the selected surface of the substrate main body 10 also has a plurality of groove-like structures 12, and the filling structure layer 20 also includes a second filling structure 22, and the second filling structure 22 is correspondingly arranged in the groove-like structure 12. It can be understood that the groove-like structure 12 is formed by being recessed along the thickness direction from the selected surface of the substrate main body 10, and the covering structure layer 30 also continuously covers the surfaces of the groove-like structure 12 and the second filling structure 22.
[0069] Specifically, the top end surface of the second filling structure 22 is flush with or lower than the selected surface of the substrate body 10 . Preferably, the top end surface of the second filling structure 22 is lower than the selected surface of the substrate body 10 .
[0070] Specifically, the area of the radial cross section of the groove-like structure 12 gradually decreases in the direction away from the selected surface, the radial width of the groove-like structure is 0.5-2 μm, and the depth of the groove-like structure is 0.1-0.5 μm. More specifically, the contour shape of the groove-like structure 12 can be a regular shape such as a cylinder, a prism, a cone, a pyramid, a truncated cone or a prism. Of course, the contour shape of the groove-like structure 12 can also be other regular shapes.
[0071] Specifically, the second filling structure 22 is located at the bottom of the groove of the groove-like structure 12. It can be understood that the contour shape of the second filling structure 22 can be the same as the portion of the groove-like structure 12 close to the bottom of the groove, and the radial cross-sectional area of the second filling structure 22 gradually decreases in the direction away from the selected surface. Specifically, the axial height of the second filling structure is 0.1-0.5 μm.
[0072] Specifically, the second filling structure 22 is the same as the first filling structure 21 , and both are silicon oxide structures.
[0073] In this embodiment, the groove structure and the boss structure set on the selected surface of the substrate body together constitute the graphic structure of the substrate body. On the one hand, the groove structure and the boss structure enlarge the height difference of the graphic result, so that the dislocation can be more fully turned in the nitride buffer layer, thereby improving the crystal quality of the nitride buffer layer, reducing the non-radiative recombination of the light-emitting layer, improving the brightness of the epitaxial wafer, and improving the leakage problem of the epitaxial wafer. On the other hand, the groove structure increases the surface area of the filling structure layer close to the light-emitting layer in the horizontal direction, so that the filling structure layer can increase the outgoing light at an angle perpendicular to the surface of the light-emitting layer, thereby improving the light emission probability and efficiency, and further improving the brightness of the epitaxial wafer.
[0074] The utility model arranges a silicon oxide filling structure on the protruding structure on the substrate body, and covers it with a silicon nitride covering structure layer with nanopores. The silicon oxide filling layer structure layer enhances the total reflection of light emitted from the light-emitting layer toward the substrate before reaching the substrate interface, thereby improving the forward light emission of the LED epitaxial wafer.
[0075] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, in which a silicon nitride covering structure layer is introduced on a filling structure layer, and the lattice constant of the silicon nitride is smaller than the lattice constant of the silicon oxide constituting the filling structure layer. Based on this, compressive stress is introduced into the epitaxial wafer, the tensile stress in the nitride buffer layer is relieved, the crystal quality and thickness uniformity of the nitride buffer layer are improved, and a high-quality light-emitting layer growth template is provided, thereby reducing the stress in the light-emitting layer.
[0076] The utility model provides a long-wave emission optoelectronic device epitaxial wafer, which improves the crystal quality and component uniformity of the light-emitting layer, reduces the non-radiative recombination caused by defects in the light-emitting layer, and especially for long-wave emission, the low-stress light-emitting layer can improve the incorporation of components in the light-emitting layer, reduces the high defect distribution caused by high stress, improves the brightness of the epitaxial wafer and improves the leakage problem.
[0077] The silicon nitride covering structure layer in the utility model utilizes its own nanoporous structure to strengthen the lateral epitaxy between the group III nitride buffer layers. Dislocations turn above the nanoscale microporous structure during the growth process, blocking the dislocations from extending upward into the nitride light-emitting layer, further improving the crystal quality of the nitride material, improving the light-emitting efficiency of the epitaxial wafer, and improving the leakage problem of the epitaxial wafer.
[0078] It should be understood that the above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the utility model.
Claims
1. A long-wave emission optoelectronic device epitaxial wafer, characterized in that: include: A substrate body, wherein a selected surface of the substrate body has a plurality of spaced-apart boss structures; A filling structure layer, comprising a plurality of first filling structures, wherein the first filling structures are correspondingly arranged on the top end surface of the boss structure; A covering structure layer is continuously covered on the substrate body and the filling structure layer, and the covering structure layer also has a plurality of microporous structures; The epitaxial structure layer includes a buffer layer, a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in sequence on the cover structure layer. Part of the buffer layer is also extended in the microporous structure and contacts the substrate body and the filling structure layer.
2. The long-wave emission optoelectronic device epitaxial wafer according to claim 1, characterized in that: The first peripheral side surface of the boss structure and the corresponding second peripheral side surface of the first filling structure are located in the same extension plane.
3. The long-wave emission optoelectronic device epitaxial wafer according to claim 1 or 2, characterized in that: The radial width of the boss structure is 0.5 to 2 μm; And / or, the axial height of the boss structure is 0.1 to 0.5 μm; And / or, the distance between two adjacent boss structures is 0.1-1 μm.
4. The long-wave emission optoelectronic device epitaxial wafer according to claim 1 or 2, characterized in that: The plurality of boss structures are distributed in an array; And / or, the radial cross-sectional area of the boss structure gradually decreases in a direction away from the selected surface.
5. The long-wave emission optoelectronic device epitaxial wafer according to claim 1 or 2, characterized in that: The radial cross-sectional area of the first filling structure gradually decreases in a direction away from the selected surface; And / or, the axial height of the first filling structure is 0.1-0.5 μm.
6. The long-wave emission optoelectronic device epitaxial wafer according to claim 3, characterized in that: The selected surface of the substrate body also has a plurality of groove-like structures, and the filling structure layer further includes a second filling structure, and the second filling structure is correspondingly arranged in the groove-like structures.
7. The long-wave emission optoelectronic device epitaxial wafer according to claim 6, characterized in that: The top end surface of the second filling structure is flush with or lower than the selected surface of the substrate body; and / or, the radial width of the groove-like structure is 0.5 to 2 μm; and / or, the depth of the groove structure is 0.1 to 0.5 μm; and / or, the area of the radial cross section of the groove-like structure gradually decreases in a direction away from the selected surface; and / or, the radial cross-sectional area of the second filling structure gradually decreases in a direction away from the selected surface; And / or, the axial height of the second filling structure is 0.1-0.5 μm.
8. The long-wave emission optoelectronic device epitaxial wafer according to claim 1, characterized in that: The covering structure layer has a contour structure that is similar to the boss structure and the first filling structure as a whole, and / or, the thickness of the covering structure layer is uniform; And / or, the thickness of the covering structure layer is 5 to 50 nm; And / or, the pore size of the microporous structure is 5 to 100 nm.
9. The long-wave emission optoelectronic device epitaxial wafer according to claim 1, characterized in that: One of the first semiconductor layer and the second semiconductor layer is a p-type semiconductor layer, and the other is an n-type semiconductor layer; And / or, the buffer layer is a Group III nitride buffer layer.
10. An optoelectronic device, characterized in that: The invention comprises the long-wave emission optoelectronic device epitaxial wafer according to any one of claims 1 to 9.
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