Light emitting diode and light emitting device

Abstract

The application relates to the technical field of semiconductor manufacturing, in particular to a light-emitting diode which comprises a first semiconductor layer, a light-emitting layer, a second semiconductor layer, a first roughening structure and a second roughening structure. The light-emitting layer is located on the first semiconductor layer, the upper surface of the first semiconductor layer which is not covered by the light-emitting layer is defined as a mesa, the second semiconductor layer is located on the light-emitting layer, the first roughening structure and the second roughening structure are both located below the first semiconductor layer, the horizontal projection of the first roughening structure is located in the horizontal projection of the light-emitting layer, the horizontal projection of the second roughening structure is located in the horizontal projection of the mesa, and the depth of the first roughening structure is greater than the depth of the second roughening structure. By arranging a larger first roughening structure on the lower surface of the first semiconductor layer corresponding to the light-emitting layer and a smaller second roughening structure on the lower surface of the first semiconductor layer corresponding to the mesa, the problem of large difference between the light-emitting intensity of the center and the edge of the chip can be solved, and the display requirement of uniform light type of the Micro LED chip can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a light emitting diode and a light emitting device. BACKGROUND

[0002] A light emitting diode (LED) is a semiconductor light emitting element, which is usually made of semiconductors such as GaN, GaAs, GaP, GaAsP, etc., and the core is a PN junction with light emitting characteristics. The LED has the advantages of high light intensity, high efficiency, small size, long service life, etc., and is considered to be one of the most potential light sources at present. The LED has been widely used in lighting, monitoring command, high-definition broadcasting, high-end cinema, office display, conference interaction, virtual reality, etc.

[0003] In recent years, Micro LED chips as the ultimate display have gradually moved towards commercialization. In the high-resolution display screens such as smart watch display and AR display, the commercialization requirements for Micro LED chips are that the chips should be able to emit light vertically to the chip plane at a small angle and the light pattern of the chips should be uniform. However, the current Micro LED chips still have the problem of large difference between the center and the edge of the light emitting intensity, which cannot meet the display requirements of uniform light pattern of Micro LED chips. Therefore, how to ensure the uniformity of the light pattern of the Micro LED chip has become one of the technical problems to be solved in the field.

[0004] It should be noted that the information disclosed in this BACKGROUND section is only intended to increase the understanding of the general background of the present application, and should not be considered as recognition or any form of suggestion that this information constitutes prior art known to those skilled in the art SUMMARY

[0005] The present application provides a light emitting diode, which comprises a first semiconductor layer, a light emitting layer, a second semiconductor layer, a first roughening structure and a second roughening structure.

[0006] The first semiconductor layer has opposite upper and lower surfaces. The light emitting layer is located on the upper surface of the first semiconductor layer, and the upper surface of the first semiconductor layer not covered by the light emitting layer is defined as a mesa. The second semiconductor layer is located above the light emitting layer. The first roughening structure is located on the lower surface of the first semiconductor layer. The second roughening structure is located on the lower surface of the first semiconductor layer. The horizontal projection of the first roughening structure is located within the horizontal projection of the light emitting layer, the horizontal projection of the second roughening structure is located within the horizontal projection of the mesa, and the depth of the first roughening structure is greater than the depth of the second roughening structure.

[0007] The application further provides a light emitting device, comprising a plurality of light emitting diodes arranged in an array, the spacing between the plurality of light emitting diodes ranges from 0.1 to 10 microns, and each light emitting diode is the light emitting diode provided by any one of the embodiments.

[0008] An embodiment of the application provides a light emitting diode and a light emitting device, by arranging a larger and sparser first rough structure on the lower surface of the first semiconductor layer corresponding to the light emitting layer and arranging a smaller and denser second rough structure on the lower surface of the first semiconductor layer corresponding to the mesa, the problem of large difference between the center and the edge of the chip in light emitting intensity can be solved, and the display requirement of uniform light type of the Micro LED chip is met.

[0009] Other features and advantages of the application will be described in the following description, and some technical features and advantages can be obtained from the description, or can be understood by implementing the application. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, some of the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0011] Figure 1 is a schematic diagram of the bottom surface structure of the light emitting diode provided by an embodiment of the application;

[0012] Figure 2 is a schematic diagram of the cross-sectional structure along the cutting line F-F shown in Figure 1

[0013] Figures 3 to 9 is a schematic diagram of the structure of the light emitting diode shown in Figure 2

[0014] Figure 10 is a schematic diagram of the structure of the light emitting diode provided by another embodiment of the application.

[0015] Reference signs:

[0016] ​​10-first semiconductor layer; 101-upper surface; 102-lower surface; 103-ta; 12-light emitting layer; 14-second semiconductor layer; 16-first roughening structure; 161-first protrusion; 18-second roughening structure; 182-second protrusion; 20-transparent conductive layer; 21-first electrode; 22-second electrode; 24-insulating layer; 26-growth substrate; 30-sacrificial layer; 32-bonding layer; 34-transferred substrate; 41-first DBR structure; 42-second DBR structure; L1-first interval; L2-second interval; H1-depth of first roughening structure; H2-depth of second roughening structure; a-inclination angle. DETAILED DESCRIPTION

[0017] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application; and the technical features in the different implementation manners described below can be combined with each other provided that there is no conflict. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0018] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms “center”, “transverse”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or component referred to must have a particular orientation, or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms “first” and “second” are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as “first” and “second” can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of “a plurality of” is two or more. In addition, the term “comprising” and any variation thereof means “at least including”.

[0019] Please refer to Figure 1 and Figure 2 , Figure 1 is a schematic view of the bottom surface structure of a light emitting diode provided by an embodiment of the present application, Figure 2 is a schematic view of the bottom surface structure of a light emitting diode provided by an embodiment of the present application, Figure 1A schematic diagram of the cross-sectional structure cut by the cut line FF. To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a light-emitting diode. As shown in the figure, the light-emitting diode may include a first semiconductor layer 10, a light-emitting layer 12, a second semiconductor layer 14, a first roughened structure 16, and a second roughened structure 18.

[0020] The first semiconductor layer 10 has an upper surface 101 and a lower surface 102. The first semiconductor layer 10 can be an N-type semiconductor layer, capable of supplying electrons to the light-emitting layer 12 under power. In some embodiments, the first semiconductor layer 10 includes an N-type doped nitride layer. The N-type doped nitride layer may include N-type impurities. N-type impurities may include one or a combination of Si, Ge, and Sn. The first semiconductor layer 10 can be a single-layer structure or a multi-layer structure with different compositions.

[0021] The light-emitting layer 12 is located on the upper surface 101 of the first semiconductor layer 10. The upper surface 101 of the first semiconductor layer 10 not covered by the light-emitting layer 12 is defined as a mesa 103, and the mesa 103 of the first semiconductor layer 10 can be used for subsequent connection of the first electrode 21. The light-emitting layer 12 can be a quantum well (QW) structure. In some embodiments, the light-emitting layer 12 can also be a multiple quantum well (MQW) structure, wherein the multiple quantum well structure includes multiple quantum well layers (Wells) and multiple quantum barrier layers (Barriers) arranged alternately in a repeating manner, such as a GaN / AlGaN, InAlGaN / InAlGaN, or InGaN / AlGaN multi-quantum well structure. Furthermore, the composition and thickness of the well layers within the light-emitting layer 12 determine the wavelength of the generated light. To improve the luminous efficiency of the light-emitting layer 12, this can be achieved by changing the depth of the quantum wells, the number of paired quantum wells and quantum barriers, the thickness, and / or other characteristics within the light-emitting layer 12. In some embodiments, the light-emitting diode has a plurality of aperture-shaped mesa surfaces 103.

[0022] The second semiconductor layer 14 is located above the light-emitting layer 12. The second semiconductor layer 14 can be a P-type semiconductor layer, which can provide holes to the light-emitting layer 12 under power. In some embodiments, the second semiconductor layer 14 includes a P-type doped nitride layer. The P-type doped nitride layer may include one or more P-type impurities. The P-type impurities may include one or a combination of Mg, Zn, and Be. The second semiconductor layer 14 can be a single-layer structure or a multi-layer structure with different compositions. Furthermore, the arrangement of the epitaxial structure is not limited to this; other types of epitaxial structures can be selected according to actual needs.

[0023] The first roughened structure 16 and the second roughened structure 18 are both located on the lower surface 102 of the first semiconductor layer 10, but they are distributed in different regions. The horizontal projection of the first roughened structure 16 lies within the horizontal projection of the light-emitting layer 12, and the horizontal projection of the second roughened structure 18 lies within the horizontal projection of the mesa 103. Comparing the first roughened structure 16 and the second roughened structure 18, the first roughened structure 16 is a larger and sparser roughening, while the second roughened structure 18 is a smaller and denser roughening. Therefore, the depth H1 of the first roughened structure 16 is greater than the depth H2 of the second roughened structure 18. Since smaller roughness and higher density result in better light emission, a larger and sparser first roughening structure 16 is provided on the lower surface 102 of the first semiconductor layer 10 corresponding to the light-emitting layer 12, and a smaller and denser second roughening structure 18 is provided on the lower surface 102 of the first semiconductor layer 10 corresponding to the mesa 103. This solves the problem of large difference in light intensity between the mesa 103 and the area with the light-emitting layer 12 due to the absence of the light-emitting layer 12, thereby solving the problem of large difference in light intensity between the center and the edge of the chip and meeting the display requirements of uniform light pattern of Micro LED chips.

[0024] The term "horizontal projection" refers to the orthographic projection of the structure onto a horizontal plane. Figure 1 Looking at the figure, the first roughened structure 16 and the second roughened structure 18 shown are their corresponding horizontal projections, and the horizontal projection of the light-emitting layer 12 is in area A circled by the dashed box.

[0025] The first roughening structure 16 includes a plurality of first protrusions 161, and the second roughening structure 18 includes a plurality of second protrusions 182. The volume of the first protrusions 161 is larger than the volume of the second protrusions 182, thus making the first roughening structure 16 a larger and sparser roughening, and the second roughening structure 18 a smaller and denser roughening, improving the light emission uniformity of the light-emitting diode. The first spacing L1 between the protrusion vertices of two adjacent first protrusions 161 is greater than the second spacing L2 between the protrusion vertices of two adjacent second protrusions 182, thus making the first roughening structure 16 a larger and sparser roughening, and the second roughening structure 18 a smaller and denser roughening, improving the light emission uniformity of the light-emitting diode. The protrusion vertices of each protrusion refer to the endpoints away from the first semiconductor layer 10 (e.g., ...). Figure 2 The lower endpoint of the first protrusion 161 and the lower endpoint of the second protrusion 182 are both present. Furthermore, the lowest point of each protrusion can also be a plane (e.g., the cross-sectional shape of the protrusion is similar to an inverted trapezoid), in which case the protrusion vertex refers to this plane. Optionally, the first spacing L1 ranges from 0.1 to 3 μm, and can be 0.2 μm; optionally, the second spacing L2 ranges from 0.01 to 1.5 μm, solving the problem of large differences in luminous intensity between the center and edge of the chip, and meeting the display requirements of uniform light pattern in Micro LED chips.

[0026] The depth H1 of the first roughening structure 16 is 1.05 to 2 times the depth H2 of the second roughening structure 18, so that the first roughening structure 16 is larger and sparser roughening, and the second roughening structure 18 is smaller and denser roughening, to improve the light-emitting diode light-emitting uniformity. In order to control the angle consistency and improve the performance of the light-emitting diode, the depth H1 of the first roughening structure 16 is 1.5 times the depth H2 of the second roughening structure 18. If the H1 and H2 multiples differ too much, the angle consistency of the first roughening structure 16 and the second roughening structure 18 will be difficult to control uniformly. Optionally, the angle difference between the first protrusion 161 and the second protrusion 182 is within a range of plus or minus 5°, or the angle difference between the first protrusion 161 and the second protrusion 182 is 2 to 4 times. Optionally, the depth H1 of the first roughening structure 16 is within a range of 0.1 to 2 μm, and the depth H2 of the second roughening structure 18 is within a range of 0.01 to 1 μm, to solve the problem of large difference between the center and the edge of the chip light-emitting intensity, and to meet the Micro LED chip light type uniform display requirements.

[0027] In some embodiments, the inclination angle α of the first protrusion 161 is within a range of 45° to 75°, which is better for light-emitting effect, and can make the light as small-angle light-emitting as much as possible. Optionally, the diameter of the first protrusion 161 is within a range of 0.5 to 2 μm, and the diameter of the second protrusion 182 is within a range of 0.1 to 1 μm.

[0028] Considering that the mesa 103 of the light-emitting diode is formed by etching part of the first semiconductor layer 10 by ICP, a large number of recombination centers will be generated after ICP etching, so that the light-emitting efficiency of the mesa 103 region is very low. In particular, the closer to the light-emitting layer 12 of the mesa 103, the lower the light-emitting efficiency, for example Figure 2 The four B regions are circled by dashed lines in the figure. Therefore, the smaller and denser design of the roughening near the mesa 103 is used to improve the light intensity, so that the light intensity of the mesa 103 and the non-mesa 103 region is uniformly distributed. That is, the horizontal projection of part of the second roughening structure 18 is located within the horizontal projection of the edge region of the light-emitting layer 12, the horizontal projection of the first roughening structure 16 is all located within the horizontal projection of the light-emitting layer 12, and the horizontal projection of part of the second roughening structure 18 is located within the horizontal projection of the mesa 103, and the rest is located within the horizontal projection of the edge of the light-emitting layer 12. The edge region of the light-emitting layer 12 refers to the region extending 0.1 to 2 μm from the outermost side of each whole light-emitting layer 12 Figure 2 to the inside of the respective light-emitting layer 12 (two whole light-emitting layers 12 in the figure) to improve the light-emitting uniformity of the light-emitting diode. If the region is greater than 2 μm, the overall light-emitting efficiency will be affected; if the region is less than 0.1 μm, the light-emitting effect of the edge region of the light-emitting layer 12 is not good, resulting in non-uniform light-emitting of the light-emitting diode.

[0029] The light emitting diode can further include a transparent conductive layer 20, an insulating layer 24, a first electrode 21 and a second electrode 22.

[0030] The transparent conductive layer 20 is located above the second semiconductor layer 14. The transparent conductive layer 20 is made of a transparent conductive material, which can include indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium doped zinc oxide (GZO), tungsten doped indium oxide (IWO), or zinc oxide (ZnO), but the embodiments of the present disclosure are not limited thereto.

[0031] The insulating layer 24 covers the first semiconductor layer 10, the light emitting layer 12, the second semiconductor layer 14 and the transparent conductive layer 20. The insulating layer 24 has a first opening and a second opening. The first opening exposes the first semiconductor layer 10, and the second opening exposes the transparent conductive layer 20. The insulating layer 24 has different functions according to the position involved, for example: when the insulating layer 24 covers the sidewalls of the first semiconductor layer 10 and the second semiconductor layer 14, it can be used to prevent the first semiconductor layer 10 and the second semiconductor layer 14 from being electrically connected by leakage of conductive material, reducing the short-circuit abnormality of the light emitting diode, but the embodiments of the present disclosure are not limited thereto. The material of the insulating layer 24 includes a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material can include silica gel. The dielectric material includes electrically insulating materials such as aluminum oxide, silicon nitride, silicon oxide, titanium oxide, or magnesium fluoride. For example, the insulating layer 24 can be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or a combination thereof, which can be a Bragg reflector (DBR) formed by repeatedly stacking two materials with different refractive indices, for example.

[0032] The first electrode 21 is electrically connected to the first semiconductor layer 10 through the first opening. The first electrode 21 can be a single-layer, double-layer or multi-layer structure, such as a laminated structure of Ti / Al, Ti / Al / Ti / Au, Ti / Al / Ni / Au, V / Al / Pt / Au, etc.

[0033] The second electrode 22 is electrically connected to the transparent conductive layer 20 through the second opening. The second electrode 22 can be a single layer, a double layer or a multi-layer structure, such as a laminated structure of Ti / Al, Ti / Al / Ti / Au, Ti / Al / Ni / Au, V / Al / Pt / Au, etc.

[0034] Referring to Figures 3 to 9 , Figures 3 to 9 is Figure 2 a schematic diagram of the structure of the light emitting diode at various stages of the manufacturing process. A method for manufacturing the light emitting diode shown in Figure 2 is disclosed below.

[0035] First, as shown in Figure 3 , a first semiconductor layer 10, a light emitting layer 12 and a second semiconductor layer 14 are sequentially deposited on a growth substrate 26. The first semiconductor layer 10, the light emitting layer 12 and the second semiconductor layer 14 are partially etched to expose a mesa 103 of the first semiconductor layer 10.

[0036] Second, as shown in Figure 4 , a transparent conductive layer 20 is formed on the second semiconductor layer 14.

[0037] Then, as shown in Figure 5 , an insulating layer 24 is deposited on the first semiconductor layer 10 and the second semiconductor layer 14, covering the first semiconductor layer 10, the light emitting layer 12, the second semiconductor layer 14 and the transparent conductive layer 20. The insulating layer 24 has a first opening and a second opening. The first opening exposes the first semiconductor layer 10, and the second opening exposes the transparent conductive layer 20.

[0038] Subsequently, as shown in Figure 6 , a first electrode 21 and a second electrode 22 are formed on the insulating layer 24. The first electrode 21 is connected to the first semiconductor layer 10 through the first opening. The second electrode 22 is connected to the transparent conductive layer 20 through the second opening.

[0039] Then, as shown in Figure 7 , a sacrificial layer 30, a bonding layer 32 and a transfer substrate 34 are sequentially arranged above the insulating layer 24, the first electrode 21 and the second electrode 22.

[0040] Then, as shown in Figure 8As shown, the growth substrate 26 located on the lower surface 102 of the first semiconductor layer 10 is removed, and the lower surface 102 of the first semiconductor layer 10 is roughened. Specifically, a larger and sparser first roughened structure 16 is formed on the lower surface 102 of the first semiconductor layer 10 corresponding to the light-emitting layer 12, a smaller and denser second roughened structure 18 is formed on the lower surface 102 of the first semiconductor layer 10 corresponding to the mesa 103, and a smaller and denser second roughened structure 18 is also formed on the lower surface 102 of the first semiconductor layer 10 corresponding to the edge region of the light-emitting layer 12.

[0041] Finally, as Figure 9 As shown, the sacrificial layer 30, bonding layer 32 and transfer substrate 34 are removed.

[0042] The above is only one publicly disclosed method for making Figure 2 The method for creating a light-emitting diode shown is not limited to this method; it is merely an example to illustrate one way of fabricating a light-emitting diode.

[0043] Please see Figure 10 , Figure 10 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Compared to Figure 2 The main difference between the LED shown in this embodiment and the LED is that the LED also includes a first DBR structure 41 and a second DBR structure 42. The first DBR structure 41 covers the first roughened structure 16 at intervals, with each first DBR structure 41 separated by a first protrusion 161, meaning there is a first protrusion 161 between two adjacent first DBR structures 41. The second DBR structure 42 covers the second roughened structure 18 at intervals, with each second DBR structure 42 separated by a second protrusion 182, meaning there is a second protrusion 182 between two adjacent second DBR structures 42. By configuring the first DBR structure 41 and the second DBR structure 42, light can be emitted through the spaced openings between the first DBR structure 41 and the second DBR structure 42, thereby forming a small-angle vertical light emission, satisfying the LED's requirement for small-angle vertical light emission.

[0044] In some embodiments, the size of the light-emitting diode is less than or equal to 50 μm, meaning the light-emitting diode is suitable for small sizes, such as Micro LEDs. The size of the light-emitting diode refers to its length or width.

[0045] The present invention also provides a light-emitting device, which includes a plurality of light-emitting diodes arranged in an array, wherein the spacing between the plurality of light-emitting diodes ranges from 0.1 to 10 μm, and each light-emitting diode is a light-emitting diode provided in any of the above embodiments.

[0046] The application provides a light emitting diode and a light emitting device, which can solve the problem of large difference between the center and the edge of the chip in light emitting intensity, and meet the display requirement of uniform light type of the Micro LED chip by arranging the first rough structure 16 with large size and sparseness on the lower surface 102 of the first semiconductor layer 10 corresponding to the light emitting layer 12, and arranging the second rough structure 18 with small size and high density on the lower surface 102 of the first semiconductor layer 10 corresponding to the mesa 103.

[0047] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present application can only be improved in one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or background art at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be regarded as a limitation to the claim.

[0048] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A light emitting diode, characterized by: The light emitting diode comprises: a first semiconductor layer having opposite upper and lower surfaces; a light emitting layer on the upper surface of the first semiconductor layer, defining a mesa of the upper surface of the first semiconductor layer not covered by the light emitting layer; a second semiconductor layer on the light emitting layer; a first roughened structure on the lower surface of the first semiconductor layer; a second roughened structure on the lower surface of the first semiconductor layer; wherein a horizontal projection of the first roughened structure is within a horizontal projection of the light emitting layer, a horizontal projection of the second roughened structure is partially within a horizontal projection of the mesa and partially within a horizontal projection of an edge of the light emitting layer, the edge region of the light emitting layer refers to a region extending 0.1-2 μm from an outermost side of the light emitting layer to an inner part of the light emitting layer, the second roughened structure has a smaller size and a higher density than the first roughened structure.

2. The light emitting diode of claim 1, wherein: The first roughened structure comprises a plurality of first protrusions, and the second roughened structure comprises a plurality of second protrusions, the first protrusions have a larger volume than the second protrusions, and a first distance between protrusion tips of two adjacent first protrusions is larger than a second distance between protrusion tips of two adjacent second protrusions.

3. The light emitting diode of claim 2, wherein: The first distance ranges from 0.1 μm to 3 μm.

4. The light emitting diode of claim 2, wherein: The second distance ranges from 0.01 μm to 1.5 μm.

5. The light emitting diode of claim 2, wherein: An inclination angle of the first protrusions ranges from 45° to 75°.

6. The light emitting diode of claim 2, wherein: The light emitting diode further comprises a first DBR structure and a second DBR structure, the first DBR structure is spacedly covering the first roughened structure, the first DBR structure is spaced by one first protrusion, the second DBR structure is spacedly covering the second roughened structure, the second DBR structure is spaced by one second protrusion.

7. The light emitting diode of claim 1, wherein: A depth of the first roughened structure is larger than a depth of the second roughened structure.

8. The light emitting diode of claim 7, wherein: The depth of the first roughened structure is 1.05 times to 2 times the depth of the second roughened structure.

9. The light emitting diode of claim 1, wherein: The depth of the first roughened structure ranges from 0.1 μm to 2 μm.

10. The light emitting diode of claim 1, wherein: The depth of the second roughened structure ranges from 0.01 μm to 1 μm.

11. The light emitting diode of claim 1, wherein: A size of the light emitting diode is less than or equal to 50 μm.

12. The light emitting diode of claim 1, wherein: The light emitting diode further comprises a transparent conductive layer, an insulating layer, a first electrode and a second electrode, the transparent conductive layer is on the second semiconductor layer, the insulating layer covers the first semiconductor layer, the light emitting layer, the second semiconductor layer and the transparent conductive layer, the insulating layer has a first opening and a second opening, the first electrode is electrically connected to the first semiconductor layer through the first opening, and the second electrode is electrically connected to the transparent conductive layer through the second opening.

13. A light-emitting device, characterized in that: The light emitting device comprises a plurality of light emitting diodes arranged in an array, a distance between the light emitting diodes ranges from 0.1 μm to 10 μm, and each light emitting diode is the light emitting diode as claimed in any one of claims 1-12.

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