Light emitting diode

Abstract

The utility model provides a light emitting diode, which comprises a substrate, a first semiconductor layer, a light emitting layer, a second semiconductor layer, a current expansion layer, an ohmic contact layer, an expansion electrode and a first electrode, and is characterized in that the first semiconductor layer, the light emitting layer and the second semiconductor layer are sequentially stacked on the substrate from bottom to top, and the current expansion layer is located on the second semiconductor layer; the ohmic contact layer covers part of the current expansion layer and exposes the remaining part of the current expansion layer, and at least one groove penetrating through the ohmic contact layer is formed in the ohmic contact layer; the expansion electrode comprises a first expansion electrode and a second expansion electrode which are connected, the first expansion electrode is located on the ohmic contact layer, the second expansion electrode is located in the groove, and the second expansion electrode is arched to expose part of the bottom of the groove; the first electrode is located on the surface of the substrate away from the first semiconductor layer. According to the utility model, the luminous intensity of the light-emitting diode is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and particularly relates to a light emitting diode. Background Art

[0002] The light emitting principle of a light emitting diode (LED) is that electrons in the N region and holes in the P region diffuse into each other, and photons are generated during the diffusion process. The light emitting diode has the advantages of high luminous efficiency, energy conservation, environmental protection, long service life, small size, etc. At present, the light emitting diode is widely used in the fields of landscape lighting, display lighting, infrared detection, etc. Improving the luminous intensity of the light emitting diode is still the top priority. Since the material of the ohmic contact layer in the light emitting diode generally has strong light absorption characteristics, reducing the light absorption ability of the ohmic contact layer is beneficial to improving the luminous intensity of the light emitting diode. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a light emitting diode to improve the luminous intensity of the light emitting diode.

[0004] To achieve the above purpose, the utility model provides a light emitting diode, including:

[0005] A substrate;

[0006] A first semiconductor layer, a light emitting layer and a second semiconductor layer, which are stacked on the substrate in sequence from bottom to top;

[0007] A current spreading layer, which is located on the second semiconductor layer;

[0008] An ohmic contact layer, which covers part of the current spreading layer and exposes the remaining part of the current spreading layer, and at least one groove penetrating through the ohmic contact layer is formed in the ohmic contact layer;

[0009] An extended electrode, the extended electrode includes a connected first extended electrode and a second extended electrode, the first extended electrode is located on the ohmic contact layer, the second extended electrode is located in the groove, and the second extended electrode is arched to expose part of the bottom of the groove;

[0010] A first electrode, which is located on the surface of the substrate away from the first semiconductor layer.

[0011] Optionally, the second extended electrode is connected to the ohmic contact layer on the side wall of the groove.

[0012] Optionally, the top of the second extended electrode is not higher than the top of the first extended electrode.

[0013] Optionally, the bottom of the groove extends into the current spreading layer.

[0014] Optionally, the cross-section of the groove is polygonal or circular.

[0015] Optionally, the extended electrode is strip-shaped.

[0016] Optionally, the size of the groove in the length direction of the extended electrode is 4 μm to 10 μm, and the distance between two adjacent grooves in the length direction of the extended electrode is 4 μm to 10 μm.

[0017] Optionally, a second electrode is further included, the second electrode is located on the current spreading layer, and the second electrode is connected to the extended electrode.

[0018] Optionally, there are multiple extended electrodes, and the second extended electrodes in two adjacent extended electrodes are arranged staggeredly in the width direction of the extended electrode, and the width direction is perpendicular to the length direction of the extended electrode.

[0019] Optionally, a bonding layer and a mirror layer are further included, and the bonding layer and the mirror layer are arranged between the substrate and the first semiconductor layer from bottom to top.

[0020] In the light-emitting diode provided by the present invention, it includes a substrate, a first semiconductor layer, a light-emitting layer, a second semiconductor layer, a current spreading layer, an ohmic contact layer, an extended electrode, and a first electrode. Among them, the first semiconductor layer, the light-emitting layer, and the second semiconductor layer are stacked on the substrate in sequence from bottom to top, and the current spreading layer is located on the second semiconductor layer; the ohmic contact layer covers a part of the current spreading layer and exposes the remaining part of the current spreading layer, and at least one groove penetrating the ohmic contact layer is formed in the ohmic contact layer; the extended electrode includes a connected first extended electrode and a second extended electrode, the first extended electrode is located on the ohmic contact layer, the second extended electrode is located in the groove, and the second extended electrode is arched to expose a part of the bottom of the groove; the first electrode is located on the surface of the substrate away from the first semiconductor layer. In the present invention, at least one groove penetrating the ohmic contact layer is formed in the ohmic contact layer. On the one hand, the area of the ohmic contact layer is reduced, and the light absorption amount of the ohmic contact layer can be reduced. On the other hand, the second extended electrode is located in the groove, and the second extended electrode is arched to expose a part of the bottom of the groove, which is beneficial for light to be emitted from the groove and reduces the light absorption of the extended electrode, thereby improving the light-emitting intensity of the light-emitting diode. Description of the Drawings

[0021] Figure 1 It is a top view of the light-emitting diode provided by Embodiment 1 of the present invention;

[0022] Figure 2 It is a schematic cross-sectional view of the light-emitting diode provided by Embodiment 1 of the present invention;

[0023] Figures 3 - 6 It is a schematic cross-sectional view of corresponding steps in the manufacturing method of the light-emitting diode provided in the first embodiment of the present invention;

[0024] Figure 7 It is a top view of the light-emitting diode provided in the second embodiment of the present invention;

[0025] Figure 8 It is a top view of the light-emitting diode provided in the third embodiment of the present invention.

[0026] Among them, the reference numerals are:

[0027] 10 - Substrate; 20 - Bonding layer; 30 - Mirror layer; 41 - First confinement layer; 42 - First spacer layer; 43 - Light-emitting layer; 44 - Second spacer layer; 45 - Second confinement layer; 50 - Current spreading layer; 60 - Ohmic contact material layer; 61 - Ohmic contact layer; 62 - Groove; 70 - Patterned photoresist layer; 80 - Extended electrode; 81 - First extended electrode; 82 - Second extended electrode; 83 - Second electrode; 90 - First electrode; 100 - Epitaxial substrate. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application that is claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0030] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, or the orientation or positional relationships in which the products of this application are usually placed during use, or the orientation or positional relationships commonly understood by those skilled in the art. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0031] Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or device comprising said element. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0032] Embodiment 1

[0033] Figure 1 The top view of the light-emitting diode provided in this embodiment, Figure 2 The cross-sectional schematic diagram of the light-emitting diode provided in this embodiment, where Figure 2 is Figure 1 the cross-sectional schematic diagram along the section line A1A2 in. Please refer to Figure 1 and Figure 2 The present utility model provides a light-emitting diode. The light-emitting diode in this embodiment is an anti-polarity light-emitting diode, which includes a substrate 10, a first semiconductor layer, a light-emitting layer 43, a second semiconductor layer, a current spreading layer 50, an ohmic contact layer 61, an extended electrode 80, and a first electrode 90. Among them, the substrate 10 is preferably a gallium arsenide substrate or a silicon substrate, and is not limited to the above materials.

[0034] On the front surface of the substrate 10 ( Figure 2 the upward surface in), a bonding layer 20 and a mirror layer 30 are sequentially arranged from bottom to top. The bonding layer 20 is used for bonding and connecting the substrate 10 and the mirror layer 30. The bonding layer 20 can be a metal stack composed of Ti, Pt, and Au, and the thickness of the bonding layer 20 is greater than 300 nm; the mirror layer 30 can be a metal stack composed of Au, AuZn, and Au, and the thickness of the mirror layer 30 is greater than 200 nm, and is not limited to the above materials and thicknesses.

[0035] The first semiconductor layer, the light-emitting layer 43, and the second semiconductor layer are stacked on the substrate 10 in sequence from bottom to top. The first semiconductor layer includes a first confinement layer 41 and a first spacer layer 42 stacked in sequence from bottom to top. The second semiconductor layer includes a second spacer layer 44 and a second confinement layer 45 stacked in sequence from bottom to top. Specifically, the first confinement layer 41, the first spacer layer 42, the light-emitting layer 43, the second spacer layer 44, and the second confinement layer 45 are stacked on the mirror layer 30 in sequence from bottom to top. In this embodiment, the material of the first confinement layer 41 can be GaP, the doping type of the first confinement layer 41 is P-type, the P-type dopant can be Mg, and the doping concentration of the first confinement layer 41 can be 1×10 17 cm -3 ~1×10 20 cm -3 , and the thickness of the first confinement layer 41 is greater than or equal to 400 nm; the material of the first spacer layer 42 can be AlGaInP, the doping type of the first spacer layer 42 is P-type, the P-type dopant can be Mg, and the doping concentration of the first spacer layer 42 can be 1×10 16 cm -3 ~1×10 19 cm -3 , and the thickness of the first spacer layer 42 is greater than or equal to 50 nm; the light-emitting layer 43 is a multi-quantum well layer, the material of the light-emitting layer 43 can be AlGaInP, and the number of periods is 1 to 20; the material of the second spacer layer 44 can be AlGaInP, the doping type of the second spacer layer 44 is N-type, the N-type dopant can be Si, and the doping concentration of the second spacer layer 44 can be 1×10 16 cm -3 ~1×10 19 cm -3 , and the thickness of the second spacer layer 44 is greater than or equal to 50 nm; the material of the second confinement layer 45 can be AlInP, the doping type of the second confinement layer 45 is N-type, the N-type dopant can be Si, and the doping concentration of the second confinement layer 45 can be 1×10 17 cm -3 ~1×10 20 cm -3 , and the thickness of the second confinement layer 45 is greater than or equal to 400 nm; the above process parameters of the first confinement layer 41, the first spacer layer 42, the light-emitting layer 43, the second spacer layer 44, and the second confinement layer 45 are only preferred illustrations and are not limited to the above process parameters.

[0036] The current spreading layer 50 is located on the second semiconductor layer. Specifically, the current spreading layer 50 is located on the second confinement layer 45. The material of the current spreading layer 50 can be AlGaInP, the doping type of the current spreading layer 50 is N-type, the N-type dopant can be Si, and the doping concentration of the current spreading layer 50 is less than or equal to 2×10 18 cm-3 , the thickness of the current spreading layer 50 can be 1 μm to 6 μm, not limited to the above process parameters.

[0037] The ohmic contact layer 61 covers a part of the current spreading layer 50 and exposes the remaining part of the current spreading layer 50. At least one groove 62 penetrating (penetrating along the thickness direction of the ohmic contact layer 61) the ohmic contact layer 61 is formed in the ohmic contact layer 61. In this embodiment, there are multiple ohmic contact layers 61. The multiple ohmic contact layers 61 are, for example, strip-shaped. The extending direction (length direction) of the multiple ohmic contact layers 61 is Figure 1 the X direction in Figure 1 , and the multiple ohmic contact layers 61 are arranged in parallel along the direction perpendicular to the length direction ( Figure 1 the Y direction in Figure 1 , the X direction and the Y direction are perpendicular), and the spacing between the multiple ohmic contact layers 61 can be the same or different. In other embodiments, the ohmic contact layer 61 can also be curved, zigzag, etc. In this embodiment, at least one groove 62 penetrating the ohmic contact layer 61 is formed in each ohmic contact layer 61. Along the length direction of the ohmic contact layer 61 ( Figure 2 the X direction in Figure 1 ), the size of the groove 62 is preferably 4 μm to 10 μm, which is beneficial to forming an arched second spreading electrode in the groove 62 later. Along the length direction of the ohmic contact layer 61 ( Figure 1 the X direction in

[0038] ), the spacing between two adjacent grooves 62 is preferably 4 μm to 10 μm, not limited to the above size and spacing; the bottom of the groove 62 can extend into the current spreading layer 50 ( 18 cm -3 , not limited to the above process parameters.

[0039] Further, the extended electrode 80 includes a connected first extended electrode 81 and a second extended electrode 82. The first extended electrode 81 is located on the ohmic contact layer 61, and the second extended electrode 82 is located in the groove 62. The second extended electrode 82 is arched to expose a part of the bottom of the groove 62 (exposing a part of the surface of the current spreading layer 50 below the second extended electrode 82). Specifically, the second extended electrode 82 contacts a part of the bottom of the groove 62 (as Figure 2 shown) to increase the connection reliability of the second extended electrode 82, making the second extended electrode 82 arched. The part below the arch is a suspended part, which is conducive to light emitting from the groove 62 (emitting from the light emitting layer 43). In this embodiment, the extended electrode 80 is preferably strip-shaped, and the length direction of the extended electrode 80 is the same as the length direction of the ohmic contact layer 61. In other embodiments, the extended electrode 80 can also be curved, zigzag, etc. There are multiple extended electrodes 80, and the extended electrodes 80 are arranged in one-to-one correspondence with the ohmic contact layer 61. The number of the second extended electrodes 82 in each extended electrode 80 is the same as the number of the grooves 62 in each ohmic contact layer 61 (the number of the second extended electrodes 82 in each extended electrode 80 is at least one). The second extended electrode 82 is connected to the ohmic contact layer 61 on the side wall of the groove 62. The top of the second extended electrode 82 is not higher than the top of the first extended electrode 81 to increase the connection reliability of the second extended electrode 82. It can be that the top of the second extended electrode 82 is lower than the top of the first extended electrode 81, or the top of the second extended electrode 82 is flush with the top of the first extended electrode 81. For example, when the top of the second extended electrode 82 is lower than the top of the first extended electrode 81, the height difference between the top of the second extended electrode 82 and the top of the first extended electrode 81 is less than or equal to 100 nm, not limited to the above height difference. And the distance between the edges of the first extended electrode 81 and the second extended electrode 82 close to the edge of the ohmic contact layer 61 can be 1 μm to 3 μm, that is, the edges of the first extended electrode 81 and the second extended electrode 82 are retracted 1 μm to 3 μm compared with the edge of the ohmic contact layer 61, not limited to the above distance. In this embodiment, the length directions ( Figure 1 the X direction in Figure 1 ) of several extended electrodes 80 are the same, and the second extended electrodes 82 in adjacent two extended electrodes 80 are staggered along the width direction ( Figure 1 the Y direction in

[0040] shown) of the extended electrode 80, so that the current spreading is more uniform and the light emitting of the light emitting diode is uniform. In this embodiment, a second electrode 83 is further included. The second electrode 83 serves as an N electrode, and the second electrode 83 is located on the current spreading layer 50. In this embodiment, the extended electrode 80 is connected to the second electrode 83. The cross section of the second electrode 83 is, for example, rectangular. The length direction ( Figure 1 the X direction inFigure 1 It is perpendicular to the Y direction (in the middle), and of course, the length direction of the extended electrode 80 and the length direction of the second electrode 83 may also have an included angle of other angles. In this embodiment, the sum of the contact areas between the second extended electrodes 82 in the grooves 62 of each ohmic contact layer 61 and the current spreading layer 50 is less than or equal to the contact area between the second electrode 83 and the current spreading layer 50. When current is injected from the second electrode 83, since the contact area between the second electrode 83 and the current spreading layer 50 is larger and the resistance is greater, the current will flow to each extended electrode 80, making the current spreading more uniform.

[0041] In this embodiment, the extended electrode 80 and the second electrode 83 are integrally arranged on the same layer, and the process parameters of the extended electrode 80 and the second electrode 83 are the same. Specifically, the materials of the extended electrode 80 and the second electrode 83 can be a metal stack composed of Au, AuGeNi, Au, Pt, and Au. The thickness of the extended electrode 80 and the second electrode 83 is greater than or equal to 2 μm, and it is not limited to the above process parameters.

[0042] Furthermore, it further includes a first electrode 90. The first electrode 90 is located on the surface of the substrate 10 away from the first semiconductor layer ( Figure 2 the downward-facing surface of the substrate 10 in the middle), and the first electrode 90 serves as a P electrode.

[0043] Figure 1 is a top view of the light-emitting diode provided in this embodiment, Figure 2 is a cross-sectional schematic diagram of the light-emitting diode provided in this embodiment, Figures 3 - 6 is a cross-sectional schematic diagram of the corresponding steps in the manufacturing method of the light-emitting diode provided in this embodiment, where Figures 3 - 6 is Figure 1 the cross-sectional schematic diagram of the corresponding steps along the section line A1A2 in the middle. This embodiment also provides a manufacturing method of a light-emitting diode for manufacturing the above-mentioned light-emitting diode.

[0044] Please refer to Figure 3 , provide an epitaxial substrate 100, and sequentially form an ohmic contact material layer 60, a current spreading layer 50, a second confinement layer 45, a second spacer layer 44, a light-emitting layer 43, a first spacer layer 42, a first confinement layer 41, and a mirror layer 30 on the epitaxial substrate 100. The process parameters of the above process layers are as described above.

[0045] Please refer to Figure 4 , provide a substrate 10, bond and connect the mirror layer 30 and the substrate 10 through a bonding layer 20, and remove the epitaxial substrate 100. Perform a photolithography process to etch the ohmic contact material layer 60 to form a plurality of ohmic contact layers 61, and at least one groove 62 penetrating the ohmic contact layer 61 is formed in the ohmic contact layer 61. The structures of the above groove 62 and the ohmic contact layer 61 are as described above.

[0046] Please refer to Figure 5 , a photoresist layer is formed to fill the groove 62 and cover the ohmic contact layer 61 and the current spreading layer 50. Then, the photoresist layer is patterned to obtain a patterned photoresist layer 70. The patterned photoresist layer 70 covers a part of the current spreading layer 50 and a part of the bottom of the groove 62 (the central region of the bottom of the groove 62). The patterned photoresist layer 70 has a certain thickness to fill a part of the groove 62, and the patterned photoresist layer 70 is baked to make it stronger.

[0047] Please refer to Figure 6 , a conductive layer is formed by evaporation to fill the groove 62 and cover the patterned photoresist layer 70, the ohmic contact layer 61, and a part of the current spreading layer 50. The conductive layer on the ohmic contact layer 61 serves as the first spreading electrode 81, the conductive layer in and directly above the groove 62 serves as the second spreading electrode 82, and the conductive layer on the current spreading layer 50 serves as the second electrode 83 (the second electrode 83 is as shown in Figure 1 ). The process parameters of the conductive layer are the same as those of the spreading electrode 80 as described above.

[0048] Please refer to Figure 2 , the patterned photoresist layer 70 is removed by ashing, so that the second spreading electrode 82 is suspended below, forming an arch structure, which is beneficial to the light emitted from the light-emitting layer 43.

[0049] Embodiment 2

[0050] Figure 7 This is a top view of the light-emitting diode provided in this embodiment. Please refer to Figure 7 , the difference between this embodiment and Embodiment 1 lies in the arrangement manner of the spreading electrode 80, and the others are the same as those in Embodiment 1, so they will not be described here.

[0051] This embodiment includes a second electrode 83, and the second electrode 83 is located on the current spreading layer 50. The spreading electrode 80 and the second electrode 83 are integrally arranged on the same layer. In this embodiment, the cross-section of the second electrode 83 is preferably circular (as shown in Figure 7 ), but is not limited to the above shape. Centered on the second electrode 83, a plurality of spreading electrodes 80 are circumferentially distributed around the second electrode 83 and are all connected to the second electrode 83. In this embodiment, the spreading electrodes 80 extend around the second electrode 83, which is beneficial to current spreading.

[0052] In addition, regardless of the shape, number, and arrangement of the ohmic contact layer 61, the shape, position, and connection method of the groove 62 to the ohmic contact layer 61, and the shape, number, and arrangement of the extended electrode 80, a groove 62 can be provided in the ohmic contact layer 61, such that a part of the extended electrode 80 (the second extended electrode 82) is arched and located in the groove 62, which is conducive to light emitting from the groove 62, reducing the light absorption of the extended electrode 80, and thus improving the light emitting intensity of the light emitting diode.

[0053] Embodiment 3

[0054] Figure 8 is a top view of the light emitting diode provided in this embodiment. Please refer to Figure 8 , the difference between this embodiment and Embodiment 1 is that the groove 62 is located in the ohmic contact layer 61 and does not penetrate the ohmic contact layer 61 along the width direction (Y direction) of the ohmic contact layer 61, that is, the ohmic contact layer 61 is not separated into multiple segments. Others are the same as Embodiment 1 and will not be described here. For the convenience of indicating the position of the groove 62, Figure 8 in one place, the groove 62 does not show the second extended electrode 82, and the bottom of the groove 62 exposes the current spreading layer 50.

[0055] In summary, in the light emitting diode provided by the present utility model, it includes a substrate, a first semiconductor layer, a light emitting layer, a second semiconductor layer, a current spreading layer, an ohmic contact layer, an extended electrode, and a first electrode. Among them, the first semiconductor layer, the light emitting layer, and the second semiconductor layer are stacked on the substrate in sequence from bottom to top, and the current spreading layer is located on the second semiconductor layer; the ohmic contact layer covers a part of the current spreading layer and exposes the remaining part of the current spreading layer, and at least one groove penetrating the ohmic contact layer is formed in the ohmic contact layer; the extended electrode includes a connected first extended electrode and a second extended electrode, the first extended electrode is located on the ohmic contact layer, the second extended electrode is located in the groove, and the second extended electrode is arched to expose a part of the bottom of the groove; the first electrode is located on the surface of the substrate away from the first semiconductor layer. In the present utility model, at least one groove penetrating the ohmic contact layer is formed in the ohmic contact layer. On the one hand, the area of the ohmic contact layer is reduced, and the light absorption amount of the ohmic contact layer can be reduced. On the other hand, the second extended electrode is located in the groove, and the second extended electrode is arched to expose a part of the bottom of the groove, which is conducive to light emitting from the groove, reducing the light absorption of the extended electrode, and thus improving the light emitting intensity of the light emitting diode.

[0056] The above is only the preferred embodiment of the present utility model and does not impose any limitation on the present utility model. Any person skilled in the art, without departing from the technical solution of the present utility model, makes any form of equivalent substitution or modification and other changes to the technical solution and technical content disclosed by the present utility model, all of which belong to the content of not departing from the technical solution of the present utility model and still fall within the protection scope of the present utility model.

Claims

1. A light-emitting diode, characterized in that, Comprising: A substrate; A first semiconductor layer, a light-emitting layer, and a second semiconductor layer, which are sequentially stacked on the substrate from bottom to top; A current spreading layer, located on the second semiconductor layer; An ohmic contact layer, covering a part of the current spreading layer and exposing the remaining part of the current spreading layer, and at least one groove penetrating through the ohmic contact layer is formed in the ohmic contact layer; An extended electrode, the extended electrode includes a connected first extended electrode and a second extended electrode, the first extended electrode is located on the ohmic contact layer, the second extended electrode is located in the groove, the second extended electrode contacts the current spreading layer at the bottom of the groove and is connected to the ohmic contact layer on the side wall of the groove, and the second extended electrode is arched, and the lower part of the arch is suspended to expose a part of the surface of the current spreading layer below the second extended electrode; A first electrode, located on the surface of the substrate away from the first semiconductor layer; A second electrode, located on the current spreading layer and connected to the extended electrode, and the sum of the contact areas of the second extended electrode and the current spreading layer is less than or equal to the contact area of the second electrode and the current spreading layer.

2. The light-emitting diode according to claim 1, wherein, The top of the second extended electrode is not higher than the top of the first extended electrode.

3. The light-emitting diode according to claim 1, wherein, The bottom of the groove extends into the current spreading layer.

4. The light-emitting diode according to claim 1, wherein The cross-section of the groove is polygonal or circular.

5. The light-emitting diode according to claim 1, wherein, The extended electrode is strip-shaped.

6. The light-emitting diode according to claim 5, characterized in that, The size of the groove in the length direction of the extended electrode is 4 μm to 10 μm, and the distance between two adjacent grooves in the length direction of the extended electrode is 4 μm to 10 μm.

7. The light-emitting diode according to claim 5, wherein There are multiple extended electrodes, and the second extended electrodes in two adjacent extended electrodes are staggered in the width direction of the extended electrode, and the width direction is perpendicular to the length direction of the extended electrode.

8. The light-emitting diode according to claim 1, wherein, It further includes a bonding layer and a mirror layer, and the bonding layer and the mirror layer are arranged on the substrate and the first semiconductor layer from bottom to top.

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