Light emitting diode and method of manufacturing light emitting diode

Abstract

This disclosure provides a light-emitting diode (LED) and a method for fabricating an LED. The LED includes: an epitaxial structure, a transparent conductive layer, a primary electrode, a reflective layer, and a secondary electrode; the epitaxial structure has a groove, the primary electrode is located at the bottom of the groove, the transparent conductive layer is located on the surface of the epitaxial structure, the reflective layer covers the epitaxial structure, the transparent conductive layer, and the primary electrode, and the secondary electrode passes through the reflective layer, and the secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

Description

Technical Field

[0001] This disclosure relates to the field of light-emitting devices, and in particular to a light-emitting diode and a method for fabricating a light-emitting diode. Background Technology

[0002] Light-emitting diodes (LEDs) are semiconductor devices that emit light. They have advantages such as energy saving, high brightness, high durability, long lifespan, and lightweight, and have been widely used in both backlight displays and direct-view displays.

[0003] The related technology provides a light-emitting diode, the structure of which includes an epitaxial structure, a reflective layer and an electrode structure, the reflective layer covering the epitaxial structure, and the electrode structure passing through the reflective layer and connected to the epitaxial structure.

[0004] Among the aforementioned light-emitting diodes (LEDs), improving their luminous efficacy is a major focus of current research. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) and a method for manufacturing an LED, which can significantly improve the luminous efficacy of the LED. The technical solution is as follows: On one hand, a light-emitting diode is provided, the light-emitting diode comprising: an epitaxial structure, a transparent conductive layer, a primary electrode, a reflective layer, and a secondary electrode; The epitaxial structure has a groove, the primary electrode is located at the bottom of the groove, the transparent conductive layer is located on the surface of the epitaxial structure, the reflective layer covers the epitaxial structure, the transparent conductive layer and the primary electrode, the secondary electrode passes through the reflective layer, and the secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

[0006] Optionally, the primary electrode is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum, and gold.

[0007] Optionally, the secondary electrode is in direct contact with the surface of the transparent conductive layer through multiple contact points, and the area of ​​each of the multiple contact points is smaller than the contact area between the primary electrode and the bottom of the groove.

[0008] Optionally, the area of ​​each contact point of the secondary electrode is 77~81μm.

[0009] Optionally, the epitaxial structure is divided into a first epitaxial structure and a second epitaxial structure by an isolation groove; the first epitaxial structure has a first groove, and the second epitaxial structure has a second groove; The primary electrode includes a first electrode and a second electrode, wherein the first electrode is located in the first groove and the second electrode is located in the second groove; The secondary electrode includes a third electrode, a fourth electrode, and a fifth electrode located on the reflective layer. The third electrode is electrically connected to the surface of the first epitaxial structure. The fourth electrode extends from the first epitaxial structure to the second epitaxial structure. One side of the fourth electrode is electrically connected to the first electrode, and the other side of the fourth electrode is electrically connected to the surface of the second epitaxial structure. The fifth electrode is electrically connected to the second electrode.

[0010] On the other hand, a method for fabricating a light-emitting diode includes: An epitaxial structure is fabricated, the epitaxial structure having a groove; A primary electrode is fabricated, the primary electrode being located at the bottom of the groove; A transparent conductive layer is fabricated on the surface of the epitaxial structure; A reflective layer is fabricated, which covers the epitaxial structure, the transparent conductive layer, and the primary electrode; A secondary electrode is fabricated, which passes through the reflective layer. The secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

[0011] Optionally, the primary electrode is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum, and gold.

[0012] Optionally, the secondary electrode is in direct contact with the surface of the transparent conductive layer through multiple contact points, and the area of ​​each of the multiple contact points is smaller than the contact area between the primary electrode and the bottom of the groove.

[0013] Optionally, the area of ​​each contact point of the secondary electrode is 77~81μm.

[0014] Optionally, the epitaxial structure is divided into a first epitaxial structure and a second epitaxial structure by an isolation groove; the first epitaxial structure has a first groove, and the second epitaxial structure has a second groove; The primary electrode includes a first electrode and a second electrode, wherein the first electrode is located in the first groove and the second electrode is located in the second groove; The secondary electrode includes a third electrode, a fourth electrode, and a fifth electrode located on the reflective layer. The third electrode is electrically connected to the surface of the first epitaxial structure. The fourth electrode extends from the first epitaxial structure to the second epitaxial structure. One side of the fourth electrode is electrically connected to the first electrode, and the other side of the fourth electrode is electrically connected to the surface of the second epitaxial structure. The fifth electrode is electrically connected to the second electrode.

[0015] The beneficial effects of the technical solutions provided in this disclosure are: In this embodiment, the epitaxial structure has a groove, with a primary electrode located at the bottom of the groove. A reflective layer covers the epitaxial structure and the primary electrode, reflecting light emitted from the epitaxial structure so that the light-emitting diode emits light from the non-electrode side, preventing light absorption by the electrodes. A secondary electrode passes through the reflective layer and is electrically connected to both the transparent conductive layer and the primary electrode. The secondary electrode contacts the surface of the transparent conductive layer through multiple contact points. In this design, the contact area between the secondary electrode and the surface of the transparent conductive layer is smaller than that of the primary electrode and the surface of the transparent conductive layer in related technologies, thereby reducing light absorption by the electrodes on the surface of the transparent conductive layer, improving the brightness of the light-emitting diode, and thus enhancing its luminous efficacy. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure; Figure 2 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 4 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 5 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 6 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 7 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 8 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 9 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 10 This is a schematic diagram of the structure of the light-emitting diode provided in the embodiments of this disclosure during the fabrication process; Figure 11 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure; Figure 12 This is a schematic diagram of the cross-section of a light-emitting diode (LED) along line A-A' provided in an embodiment of this disclosure.

[0018] The attached figures are labeled as follows: 10: Epitaxial structure; 11: First epitaxial structure; 12: Second epitaxial structure; 20: Primary electrode; 30: Secondary electrode; 40: Electrode pad structure; 100: Substrate; 101: First semiconductor layer; 102: Active layer; 103: Second semiconductor layer; 104: Current blocking layer; 105: Transparent conductive layer; 106: Reflective layer; 107: Passivation layer; 1041: First current blocking layer; 1042: Second current blocking layer; 1051: First transparent conductive layer; 1052: Second transparent conductive layer; 201: First electrode; 202: Second electrode; 301: Third electrode; 302: Fourth electrode; 303: Fifth electrode; 321: First part; 322: Second part; 31: Contact point; 401: First electrode pad; 402: Second electrode pad; 1000: Isolation groove; 1001: First through hole; 1002: Second through hole; 1003: Third through hole; 200: Groove; 2001: First groove; 2002: Second groove. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0020] Figure 1 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 1 The method includes the following steps: S11. Fabricate an epitaxial structure, wherein the epitaxial structure has a groove.

[0021] S12. Fabricate a primary electrode, which is located at the bottom of the groove and is a light-absorbing metal electrode.

[0022] S13. Fabricate a transparent conductive layer, wherein the transparent conductive layer is located on the surface of the epitaxial structure.

[0023] S14. Fabricate a reflective layer, which covers the epitaxial structure, the transparent conductive layer, and the primary electrode.

[0024] S15. Fabricate a secondary electrode that passes through the reflective layer. The secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

[0025] In this embodiment, the epitaxial structure has a groove, with a primary electrode located at the bottom of the groove. A reflective layer covers the epitaxial structure and the primary electrode, reflecting light emitted from the epitaxial structure so that the light-emitting diode emits light from the non-electrode side, preventing light absorption by the electrodes. A secondary electrode passes through the reflective layer and is electrically connected to both the transparent conductive layer and the primary electrode. The secondary electrode contacts the surface of the transparent conductive layer through multiple contact points. In this design, the contact area between the secondary electrode and the surface of the transparent conductive layer is smaller than that of the primary electrode and the surface of the transparent conductive layer in related technologies, thereby reducing light absorption by the electrodes on the surface of the transparent conductive layer, improving the brightness of the light-emitting diode, and thus enhancing its luminous efficacy.

[0026] Figure 2 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 2 The method includes the following steps: S21. A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially formed on a substrate, and the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial structure.

[0027] The substrate can be a sapphire substrate.

[0028] In one example, step S21 includes: The first step is to fabricate the first semiconductor layer on the substrate.

[0029] In this embodiment of the disclosure, the first semiconductor layer may be an N-type semiconductor layer. For example, the first semiconductor layer may be an N-type GaN layer.

[0030] In other embodiments, the first semiconductor layer may be a P-type semiconductor layer.

[0031] The second step is to fabricate an active layer on the first semiconductor layer.

[0032] In the embodiments disclosed herein, the active layer is a multi-quantum-well layer. For example, the active layer is an InGaN / GaN multi-quantum-well layer.

[0033] The third step is to fabricate a second semiconductor layer on the active layer.

[0034] In this embodiment of the disclosure, the second semiconductor layer may be a P-type semiconductor layer. For example, the second semiconductor layer may be a P-type GaN layer.

[0035] In other embodiments, the second semiconductor layer may be an N-type semiconductor layer.

[0036] In this embodiment of the disclosure, a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially stacked on a substrate.

[0037] In the embodiments disclosed herein, the above-mentioned semiconductor layer can be grown using a Veeco K465i, C4, or RB MOCVD (Metal Organic Chemical Vapor Deposition) apparatus or an AIXTRON MOCVD apparatus. High-purity H2 (hydrogen), high-purity N2 (nitrogen), or a mixture of high-purity H2 and high-purity N2 is used as the carrier gas; high-purity NH3 is used as the N source; trimethylgallium (TMGa) and triethylgallium (TEGa) are used as gallium sources; trimethylindium (TMIn) is used as the indium source; silane (SiH4) is used as the N-type dopant; trimethylaluminum (TMAl) is used as the aluminum source; and magnesium pyrocene (CP2Mg) is used as the P-type dopant.

[0038] It is worth noting that other equipment can also be used to fabricate the aforementioned semiconductor layer, and this disclosure does not limit this.

[0039] S22. The epitaxial structure is patterned to form a first epitaxial structure and a second epitaxial structure. The first epitaxial structure has a first groove, the second epitaxial structure has a second groove, and there is an isolation groove between the first epitaxial structure and the second epitaxial structure.

[0040] In this embodiment, a two-stage photolithography development and dry etching technique is used to etch the epitaxial structure.

[0041] The method of using two-stage photolithography development and dry etching refers to first using the first stage of photolithography development and dry etching to create isolation trenches, forming the first epitaxial structure and the second epitaxial structure; then using the second stage of photolithography development and dry etching to create the first groove and the second groove.

[0042] Figure 3 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 3The epitaxial structure 10 has an isolation groove 1000, which divides the epitaxial structure 10 into a first epitaxial structure 11 and a second epitaxial structure 12. The first epitaxial structure 11 has a first groove 2001, and the second epitaxial structure 12 has a second groove 2002.

[0043] S23. Fabricate a current blocking layer, which includes a first current blocking layer and a second current blocking layer, and the first current blocking layer and the second current blocking layer are located on the first epitaxial structure and the second epitaxial structure, respectively.

[0044] For example, step S23 may include: The first step is to deposit a current-blocking film.

[0045] In this embodiment of the disclosure, the current blocking film can be a current blocking film fabricated by plasma enhanced chemical vapor deposition (PECVD).

[0046] In this embodiment of the disclosure, the current blocking film can be an AlGaN or SiO2 layer.

[0047] For example, the current blocking film is a SiO2 current blocking layer.

[0048] The second step is to coat a layer of photoresist onto the current blocking film.

[0049] The third step is to expose and develop the photoresist to obtain a photoresist mask layer.

[0050] The fourth step involves etching the current blocking film layer under the cover of the photoresist mask layer to form the first current blocking layer and the second current blocking layer.

[0051] In this embodiment of the disclosure, the current blocking film layer is subjected to buffered oxide etching (BOE).

[0052] In this embodiment, the current blocking layer includes 4 to 8 current blocking blocks, and the projection of the current blocking blocks on the surface of the epitaxial structure can be circular. Specifically, 2 to 4 current blocking blocks are located on the first epitaxial structure, and the projections of these 2 to 4 current blocking blocks on the surface of the first epitaxial structure surround the first groove; the projections of the other 2 to 4 current blocking blocks on the surface of the second epitaxial structure surround the second groove.

[0053] For example, the current blocking layer includes eight current blocking blocks. Four of the current blocking blocks are located on the first epitaxial structure, and the projections of the four current blocking blocks on the surface of the first epitaxial structure are rectangularly distributed around the first groove. The projections of the other four current blocking blocks on the surface of the second epitaxial structure are rectangularly distributed around the second groove.

[0054] In other examples, the projection of the current blocking block onto the surface of the epitaxial structure can also be rectangular or other shapes.

[0055] Figure 4 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 4 ,exist Figure 3 A current blocking layer is fabricated on the basis of the first epitaxial structure 11 and the second epitaxial structure 12. The current blocking layer 104 includes a first current blocking layer 1041 and a second current blocking layer 1042, which are respectively located on the first epitaxial structure 11 and the second epitaxial structure 12.

[0056] The first current blocking layer 1041 and the second current blocking layer 1042 each include four current blocking blocks.

[0057] S24. Fabricate a transparent conductive layer, which includes a first transparent conductive layer and a second transparent conductive layer. The first transparent conductive layer and the second transparent conductive layer respectively cover the first current blocking layer and the second current blocking layer, and are respectively connected to the first epitaxial structure and the second epitaxial structure.

[0058] For example, step S24 may include: The first step is to deposit a transparent conductive film layer on the first current blocking layer and the second current blocking layer.

[0059] In this embodiment of the disclosure, the transparent conductive film layer can be an indium tin oxide (ITO) layer. ITO has excellent transparency and conductivity, and can conduct current to form an electrical connection while light passes through.

[0060] The second step is to coat a layer of photoresist onto the transparent conductive film.

[0061] The third step is to expose and develop the photoresist to obtain a photoresist mask layer.

[0062] The fourth step involves etching the transparent conductive film layer under the cover of the photoresist mask layer to form the first and second transparent conductive layers.

[0063] In this embodiment of the disclosure, the transparent conductive film layer is etched using BOE etching.

[0064] Figure 5 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 5 ,exist Figure 4A transparent conductive layer is fabricated on the basis of the first transparent conductive layer 105, which includes a first transparent conductive layer 1051 and a second transparent conductive layer 1052. The first transparent conductive layer 1051 and the second transparent conductive layer 1052 respectively cover the first current blocking layer 1041 and the second current blocking layer 1042, and are respectively connected to the first epitaxial structure 11 and the second epitaxial structure 12. The first transparent conductive layer 1051 exposes the first groove 2001, and the second transparent conductive layer 1052 exposes the second groove 2002.

[0065] S25. Fabricate a primary electrode, which includes a first electrode located in a first groove and a second electrode located in a second groove.

[0066] In this embodiment of the disclosure, a first electrode is formed in a first groove using a metal evaporation process, and a second electrode is formed in a second groove.

[0067] In this embodiment of the disclosure, the primary electrode is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum, and gold.

[0068] In this implementation, the metal stack made of the aforementioned metal has good conductivity, which is beneficial for achieving low-resistance ohmic contacts.

[0069] For example, the primary electrode is a metal stack composed of cadmium, aluminum, titanium, nickel, platinum and gold.

[0070] In this embodiment of the disclosure, the first electrode and the second electrode can be N electrodes.

[0071] In other embodiments, the first electrode and the second electrode may be P electrodes.

[0072] Figure 6 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 6 ,exist Figure 5 A primary electrode is fabricated based on the above. The primary electrode 20 includes a first electrode 201 and a second electrode 202. The first electrode 201 is located in the first groove 2001 and is insulated from the sidewall of the first groove 2001. The second electrode 202 is located in the second groove 2002 and is insulated from the sidewall of the second groove 2002.

[0073] S26. Create a reflective layer.

[0074] For example, step S26 may include: The first step is to make a reflective film.

[0075] In this embodiment of the disclosure, a reflective film is deposited using a physical vapor deposition (PVD) coating machine.

[0076] In this embodiment of the disclosure, the reflective film may be a distributed Bragg reflector (DBR) reflective film.

[0077] In this embodiment of the disclosure, the DBR reflective film can be a stack of alternating SiO2 and Ti3O5 layers.

[0078] In this embodiment of the disclosure, the alternation period of the SiO2 layer and the Ti3O5 layer can be 4 to 13 cycles.

[0079] For example, the alternation period of SiO2 layer and Ti3O5 layer can be 6 cycles.

[0080] The second step is to create the first through-hole in the reflective film to form a reflective layer.

[0081] In this embodiment of the disclosure, a first through-hole is fabricated on the reflective film using a dry etching technique.

[0082] In this embodiment, the reflective layer has 4 to 8 first through holes, wherein the projections of 2 to 4 first through holes are located on a first epitaxial structure, and the projections of the other 2 to 4 first through holes are located on a second epitaxial structure. The 2 to 4 first through holes on the first epitaxial structure are arranged around a first groove, and the 2 to 4 first through holes form a rectangle; the 2 to 4 first through holes on the second epitaxial structure are arranged around a second groove, and the 2 to 4 first through holes form a rectangle.

[0083] In this implementation, the reflective layer has 4 to 8 first through holes. When the secondary electrode is fabricated in the subsequent process, the secondary electrode can be electrically connected to the transparent conductive layer through the 4 to 8 first through holes. The arrangement of the first through holes around the first groove can prevent the contact area between the secondary electrode and the transparent conductive layer from being too large and absorbing too much light. In addition, it can ensure the conduction of current while making the current diffuse evenly.

[0084] In this embodiment, the reflective layer has eight first through holes, wherein the projections of four first through holes are located on a first epitaxial structure, and the projections of the other four first through holes are located on a second epitaxial structure. The four first through holes on the first epitaxial structure are arranged around a first groove, and the four first through holes form a rectangle; the four first through holes on the second epitaxial structure are arranged around a second groove, and the four first through holes form a rectangle.

[0085] In other embodiments, the reflective layer may also have a different number of first vias, for example, six first vias. Three of the first vias are projected onto the first epitaxial structure, and the other three are projected onto the second epitaxial structure. The three first vias on the first epitaxial structure are arranged around the first groove, forming a triangle; the three first vias on the second epitaxial structure are arranged around the second groove, forming a triangle.

[0086] Figure 7 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 7 ,exist Figure 6 A reflective layer is fabricated on the basis of the epitaxial structure 10 and the primary electrode 20. The reflective layer 106 covers the epitaxial structure 10 and the primary electrode 20, and the reflective layer 106 has a plurality of first through holes 1001 corresponding to each current blocking block.

[0087] S27. Fabricate a secondary electrode that passes through the reflective layer. The secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

[0088] Here, the secondary electrode makes indirect contact with the surface of the epitaxial structure through multiple contact points with the surface of the transparent conductive layer.

[0089] In this embodiment, the secondary electrode is in direct contact with the surface of the transparent conductive layer through multiple contact points, and the area of ​​each contact point is smaller than the contact area between the primary electrode and the bottom of the groove.

[0090] In this implementation, the area of ​​each of the multiple contact points is smaller than the contact area between the primary electrode and the bottom of the groove, and the contact area between the secondary electrode and the surface of the transparent conductive layer is smaller than the contact area between the primary electrode and the surface of the transparent conductive layer in related technologies. This reduces the light absorption of the electrodes on the surface of the transparent conductive layer, improves the brightness of the light-emitting diode, and thus enhances the luminous efficiency of the light-emitting diode.

[0091] In this embodiment of the disclosure, a secondary electrode is deposited using a metal evaporator, and the secondary electrode contacts the surface of the epitaxial structure through multiple contact points.

[0092] In this embodiment of the disclosure, the secondary electrode is in contact with the surface of the transparent conductive layer through 4 to 8 contact points.

[0093] In this implementation, the secondary electrode contacts the surface of the transparent conductive layer through 4 to 8 contact points. This ensures sufficient contact between the secondary electrode and the surface of the transparent conductive layer to guarantee current conduction, while also preventing the secondary electrode from absorbing light due to an excessively large contact area.

[0094] The secondary electrode, which is in contact with the surface of the transparent conductive layer through 4 to 8 contact points, refers to the entire secondary electrode, that is, the entire light-emitting diode, which includes 4 to 8 contact points, and the contact points correspond to the first through hole.

[0095] For example, the secondary electrode is in contact with the surface of the transparent conductive layer through 4, 6, or 8 contact points.

[0096] In this embodiment of the disclosure, the area of ​​each contact point of the secondary electrode is 77~81μm.

[0097] In this implementation, the area of ​​each contact point of the secondary electrode is 77~81μm. The contact area of ​​each contact point is not too small, as a small contact area will cause current accumulation, which will cause the light-emitting diode to heat up and reduce the yield of the light-emitting diode. The contact area of ​​each contact point is also not too large, as a large contact area will cause the secondary electrode to absorb light, which will reduce the brightness of the light-emitting diode.

[0098] For example, the area of ​​each contact point of the secondary electrode is 79 μm.

[0099] In this embodiment of the disclosure, the third electrode, the fourth electrode, and the fifth electrode can be stacked electrodes composed of at least two of Ti, Al, Pt, and Ti.

[0100] For example, the third, fourth and fifth electrodes are electrodes made of Ti and Al.

[0101] In this embodiment, the third electrode is a U-shaped structure, with the two arms of the U-shaped structure passing through the first through-hole of the reflective layer and connecting to the surface of the first epitaxial structure.

[0102] In this implementation, the third electrode has a U-shaped structure that can avoid the first electrode in the first groove and connect with the first epitaxial structure, thus optimizing the electrode arrangement and making the light-emitting diode structure more compact.

[0103] In this embodiment of the disclosure, the fourth electrode includes a first part and a second part. The first part is strip-shaped, and the second part is a U-shaped structure. One end of the first part is located in the first epitaxial structure and connected to the first electrode, and the other end of the first part extends to the second epitaxial structure and is connected to the second part. The two sides of the U-shaped structure pass through the first through hole of the reflective layer and are respectively connected to the second epitaxial structure.

[0104] In this implementation, the fourth electrode includes a first part and a second part. The first part is strip-shaped and can be connected to the first electrode alone. The second part is a U-shaped structure. The two sides of the U-shaped structure pass through the first through hole of the reflective layer and are respectively connected to the second epitaxial structure. The U-shaped structure can increase the current expansion area, avoid current accumulation, and increase the brightness of the light-emitting diode. The other end of the first part extends to the second epitaxial structure and connects with the second part, so that the first epitaxial structure and the second epitaxial structure can be connected in series.

[0105] In this embodiment of the disclosure, the fifth electrode is located between the two sides of the U-shaped structure of the second part.

[0106] In this implementation, the fifth electrode is located between the two sides of the U-shaped structure in the second part, which can avoid contact between the fifth electrode and the U-shaped structure, and at the same time make the structure of the light-emitting diode more compact.

[0107] In this embodiment of the disclosure, the fifth electrode is an arched window, with the arched portion of the window facing the direction of the first extensional structure.

[0108] In this implementation, the fifth electrode is an arched window, with the arched portion of the window facing the direction of the first epitaxial structure, which allows for more uniform current diffusion. This further optimizes the current distribution and improves the brightness of the light-emitting diode.

[0109] Figure 8 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 8 ,exist Figure 7 A secondary electrode is fabricated based on the first epitaxial structure 11. The secondary electrode 30 includes a third electrode 301, a fourth electrode 302, and a fifth electrode 303 located on the reflective layer 106. The third electrode 301 is electrically connected to the surface of the first epitaxial structure 11. The fourth electrode 302 extends from the first epitaxial structure 11 to the second epitaxial structure 12. One side of the fourth electrode 302 is electrically connected to the first electrode 201, and the other side of the fourth electrode 302 is electrically connected to the surface of the transparent conductive layer 105. The fifth electrode 303 is electrically connected to the second electrode 202.

[0110] S28. Fabricate a passivation layer, which covers the reflective layer and the secondary electrode.

[0111] In this embodiment of the disclosure, step S28 may include: The first step is to create a passivation layer.

[0112] In this embodiment of the disclosure, the passivation layer can be a passivation layer fabricated by plasma-enhanced chemical vapor deposition (PECVD).

[0113] In this embodiment of the disclosure, the passivation layer may be SiO2, Si3N4, or SiN. x Or a passivation layer made of SiON, where x is greater than 0.

[0114] For example, the passivation layer is a SiO2 layer.

[0115] In this embodiment of the disclosure, the thickness of the passivation layer can be 10,000 to 30,000 angstroms.

[0116] For example, the thickness of the passivation layer is 20,000 angstroms.

[0117] The second step is to create a second and a third through-hole by opening holes in the passivation layer.

[0118] In this embodiment of the disclosure, the passivation layer may include 2 to 6 second vias and 1 to 3 third vias.

[0119] For example, the passivation layer includes four second vias and one third via. The four second vias are grouped in pairs, and their projections on the bottom surface of the first epitaxial structure do not coincide with the projections of the current blocking layer on the bottom surface of the first epitaxial structure. The projection of the one third via on the bottom surface of the second epitaxial structure is located on the fifth electrode.

[0120] In this implementation, the four-hole second through-hole can make the secondary electrode and the second semiconductor layer conductive, and the above arrangement can prevent current concentration.

[0121] In other embodiments, the passivation layer may also include other numbers of second and third vias. For example, six second vias and two third vias.

[0122] In this embodiment, the second through hole is circular or elliptical, and the third through hole is a rounded rectangle.

[0123] Figure 9 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 9 ,exist Figure 8 A passivation layer is fabricated on the basis of the passivation layer 107, which covers the reflective layer 106 and the secondary electrode 30.

[0124] S29. Fabricate an electrode pad structure, which includes a first electrode pad and a second electrode pad. The first electrode pad passes through the passivation layer and is connected to the third electrode, and the second electrode pad passes through the passivation layer and is connected to the fifth electrode.

[0125] In this embodiment, a first electrode pad and a second electrode pad are deposited by metal evaporation. The first electrode pad passes through the passivation layer and is connected to the third electrode, and the second electrode pad passes through the passivation layer and is connected to the fifth electrode.

[0126] In this embodiment of the disclosure, the first electrode pad and the second electrode pad can be Cr, Al, Ti, Ni, Pt or Au electrodes.

[0127] Alternatively, the first electrode pad and the second electrode pad can be a stacked electrode composed of Ti, Al, Ni and Au.

[0128] For example, the first electrode pad and the second electrode pad are Cr electrodes.

[0129] Figure 10 This is a schematic diagram of the structure of a light-emitting diode (LED) provided in an embodiment of this disclosure during its fabrication process. See also... Figure 10 ,exist Figure 9 Based on this, an electrode pad structure is fabricated. The electrode pad structure 40 includes a first electrode pad 401 and a second electrode pad 402. The first electrode pad 401 passes through the second through hole 1002 of the passivation layer 107 and is connected to the third electrode 301. The second electrode pad 402 passes through the third through hole 1003 of the passivation layer 107 and is connected to the fifth electrode 303.

[0130] S30, thinned substrate.

[0131] By thinning and grinding, the chip thickness can be reduced to match the needs of downstream markets.

[0132] S31, Cutting the light-emitting diode.

[0133] In this embodiment of the disclosure, step S31 may include: The first step is to dicing the light-emitting diodes.

[0134] In this embodiment, the front side of the entire wafer is attached to an adhesive polymer film, and the back side is diced using a hidden dicing machine. Based on the wafer structure, the wafer is cut in the order of first the obliquely diced side and then the non-obliquely diced side.

[0135] The second step is to cleave the fragments.

[0136] After the hidden dicing machine completes its processing, the wafer is diced.

[0137] The third step is to perform automated optical inspection (AOI).

[0138] The fourth step is to pour and expand the film.

[0139] Figure 11 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. (Reference) Figure 11 The light-emitting diode includes: an epitaxial structure 10, a transparent conductive layer 105, a primary electrode 20, a reflective layer 106, and a secondary electrode 30.

[0140] Figure 12 This is a schematic diagram of the cross-section A-A' of a light-emitting diode provided in an embodiment of this disclosure. See also... Figures 3 to 12 The epitaxial structure 10 has a groove 200, a primary electrode 20 is located at the bottom of the groove 200, a transparent conductive layer 105 is located on the surface of the epitaxial structure 10, a reflective layer 106 covers the epitaxial structure 10, the transparent conductive layer 105 and the primary electrode 20, and a secondary electrode 30 passes through the reflective layer 106. The secondary electrode 30 includes a portion that is in direct contact with the surface of the transparent conductive layer 105 and a portion that is in direct contact with the primary electrode 20.

[0141] In this embodiment, the epitaxial structure has a groove, with a primary electrode located at the bottom of the groove. A reflective layer covers the epitaxial structure and the primary electrode, reflecting light emitted from the epitaxial structure so that the light-emitting diode emits light from the non-electrode side, preventing light absorption by the electrodes. A secondary electrode passes through the reflective layer and is electrically connected to both the transparent conductive layer and the primary electrode. The secondary electrode contacts the surface of the transparent conductive layer through multiple contact points. In this design, the contact area between the secondary electrode and the surface of the transparent conductive layer is smaller than that of the primary electrode and the surface of the transparent conductive layer in related technologies, thereby reducing light absorption by the electrodes on the surface of the transparent conductive layer, improving the brightness of the light-emitting diode, and thus enhancing its luminous efficacy.

[0142] In this embodiment of the disclosure, the primary electrode 20 is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum and gold.

[0143] In this implementation, the metal stack made of the aforementioned metal has good conductivity, which is beneficial for achieving low-resistance ohmic contacts.

[0144] For example, the primary electrode 20 is a metal stack composed of cadmium, aluminum, titanium, nickel, platinum and gold.

[0145] In this embodiment, the secondary electrode 30 is in direct contact with the surface of the transparent conductive layer 105 through multiple contact points 31, and the area of ​​each contact point 31 is smaller than the contact area between the primary electrode 20 and the bottom of the groove 200.

[0146] In this implementation, the area of ​​each of the multiple contact points is smaller than the contact area between the primary electrode and the bottom of the groove, and the contact area between the secondary electrode and the surface of the transparent conductive layer is smaller than the contact area between the primary electrode and the surface of the transparent conductive layer in related technologies. This reduces the light absorption of the electrodes on the surface of the transparent conductive layer, improves the brightness of the light-emitting diode, and thus enhances the luminous efficiency of the light-emitting diode.

[0147] In this embodiment of the disclosure, the secondary electrode 30 is in contact with the surface of the transparent conductive layer 105 through 4 to 8 contact points 31.

[0148] In this implementation, the secondary electrode contacts the surface of the transparent conductive layer through 4 to 8 contact points. This ensures sufficient contact between the secondary electrode and the surface of the transparent conductive layer to guarantee current conduction, while also preventing the secondary electrode from absorbing light due to an excessively large contact area.

[0149] For example, the secondary electrode 30 is in contact with the surface of the transparent conductive layer 105 through eight contact points 31.

[0150] The secondary electrode 30 is in contact with the surface of the transparent conductive layer 105 through 4 to 8 contact points 31. The secondary electrode 30 refers to the entire secondary electrode 30, that is, the entire light-emitting diode includes 4 to 8 contact points 31, and the contact points 31 correspond to the first through hole 1001.

[0151] In this embodiment of the disclosure, the area of ​​each contact point 31 of the secondary electrode 30 is 77~81μm.

[0152] In this implementation, the area of ​​each contact point of the secondary electrode is 77~81μm. The contact area of ​​each contact point is not too small, as a small contact area will cause current accumulation, which will cause the light-emitting diode to heat up and reduce the yield of the light-emitting diode. The contact area of ​​each contact point is also not too large, as a large contact area will cause the secondary electrode to absorb light, which will reduce the brightness of the light-emitting diode.

[0153] For example, the area of ​​each contact point 31 of the secondary electrode 30 is 79 μm.

[0154] In this embodiment of the disclosure, the epitaxial structure 10 is divided into a first epitaxial structure 11 and a second epitaxial structure 12 by an isolation groove 1000. The first epitaxial structure 11 has a first groove 2001, and the second epitaxial structure 12 has a second groove 2002.

[0155] The primary electrode 20 includes a first electrode 201 and a second electrode 202. The first electrode 201 is located in the first groove 2001, and the second electrode 202 is located in the second groove 2002.

[0156] The secondary electrode 30 includes a third electrode 301, a fourth electrode 302, and a fifth electrode 303 located on the reflective layer 106. The third electrode 301 is electrically connected to the surface of the first epitaxial structure 11. The fourth electrode 302 extends from the first epitaxial structure 11 to the second epitaxial structure 12. One side of the fourth electrode 302 is electrically connected to the first electrode 201, and the other side of the fourth electrode 302 is electrically connected to the surface of the second epitaxial structure 12. The fifth electrode 303 is electrically connected to the second electrode 202.

[0157] In this implementation, the epitaxial structure is divided into a first epitaxial structure and a second epitaxial structure by an isolation trench. In each of the two epitaxial structures, an electrode within the trench is connected to a first semiconductor layer. Then, an electrode on the reflective layer connects the electrode within the trench of the first epitaxial structure to the second semiconductor layer of the second epitaxial structure, achieving series connection between the first and second epitaxial structures. Furthermore, two additional electrodes on the reflective layer serve as lead-out electrodes; one lead-out electrode is connected to the second semiconductor layer of the first epitaxial structure, and the other lead-out electrode is connected to the electrode within the trench of the second epitaxial structure. This electrode distribution and connection method optimizes the electrode distribution and improves the current diffusion path, enabling diffusion throughout the entire epitaxial layer and further enhancing the brightness of the light-emitting diode.

[0158] In this embodiment, the reflective layer 106 has 4 to 8 first through holes 1001, wherein the projections of 2 to 4 first through holes 1001 are located on the first epitaxial structure 11, and the projections of the other 2 to 4 first through holes 1001 are located on the second epitaxial structure 12. The 2 to 4 first through holes 1001 on the first epitaxial structure 11 are arranged around the first groove 2001, and the 2 to 4 first through holes 1001 form a rectangle; the 2 to 4 first through holes 1001 on the second epitaxial structure 12 are arranged around the second groove 2002, and the 2 to 4 first through holes 1001 form a rectangle.

[0159] In this implementation, the reflective layer has 4 to 8 first through holes. When the secondary electrode is fabricated in the subsequent process, the secondary electrode can be electrically connected to the transparent conductive layer through the 4 to 8 first through holes. The arrangement of the first through holes around the first groove can prevent the contact area between the secondary electrode and the transparent conductive layer from being too large and absorbing too much light. In addition, it can ensure the conduction of current while making the current diffuse evenly.

[0160] In this embodiment, the reflective layer 106 has eight first through holes 1001, wherein the projections of four first through holes 1001 are located on the first epitaxial structure 11, and the projections of the other four first through holes 1001 are located on the second epitaxial structure 12. The four first through holes 1001 on the first epitaxial structure 11 are arranged around the first groove 2001, and the four first through holes 1001 form a rectangle; the four first through holes 1001 on the second epitaxial structure 12 are arranged around the second groove 2002, and the four first through holes 1001 form a rectangle.

[0161] In other embodiments, the reflective layer 106 may also have other numbers of first through holes 1001, for example, six first through holes 1001. Three of the first through holes 1001 are projected onto the first epitaxial structure 11, and the other three are projected onto the second epitaxial structure 12. The three first through holes 1001 on the first epitaxial structure 11 are arranged around the first groove 2001, and the three first through holes 1001 form a triangle; the three first through holes 1001 on the second epitaxial structure 12 are arranged around the second groove 2001, and the three first through holes 1001 form a triangle.

[0162] In this embodiment, the third electrode 301 has a U-shaped structure, and the two arms of the U-shaped structure pass through the first through hole 1001 of the reflective layer 106 and are connected to the surface of the first epitaxial structure 11.

[0163] In this implementation, the third electrode has a U-shaped structure that can avoid the first electrode in the first groove and connect with the first epitaxial structure, thus optimizing the electrode arrangement and making the light-emitting diode structure more compact.

[0164] In this embodiment, the fourth electrode 302 includes a first part 321 and a second part 322. The first part 321 is strip-shaped, and the second part 322 is a U-shaped structure. One end of the first part 321 is located at the first epitaxial structure 11 and connected to the first electrode 201. The other end of the first part 321 extends to the second epitaxial structure 12 and is connected to the second part 322. The two sides of the U-shaped structure pass through the first through hole 1001 of the reflective layer 106 and are respectively connected to the second epitaxial structure 12.

[0165] In this implementation, the fourth electrode includes a first part and a second part. The first part is strip-shaped and can be connected to the first electrode alone. The second part is a U-shaped structure. The two sides of the U-shaped structure are respectively connected to the second epitaxial structure. The U-shaped structure can increase the current expansion area, avoid current accumulation, and increase the brightness of the light-emitting diode. The other end of the first part extends to the second epitaxial structure and connects with the second part, so that the first epitaxial structure and the second epitaxial structure can be connected in series.

[0166] In this embodiment of the disclosure, the fifth electrode 303 is located between the two sides of the U-shaped structure of the second part 322.

[0167] In this implementation, the fifth electrode is located between the two sides of the U-shaped structure in the second part, which can avoid contact between the fifth electrode and the U-shaped structure, and at the same time make the structure of the light-emitting diode more compact.

[0168] In this embodiment of the disclosure, the fifth electrode 303 is an arched window, and the arched portion of the arched window faces the direction of the first extensional structure 11.

[0169] In this implementation, the fifth electrode is an arched window, with the arched portion of the window facing the direction of the first epitaxial structure, which allows for more uniform current diffusion. This further optimizes the current distribution and improves the brightness of the light-emitting diode.

[0170] Optionally, the light-emitting diode also includes a current blocking layer 104.

[0171] The current blocking layer 104 is located between the epitaxial structure 10 and the transparent conductive layer 105.

[0172] The current blocking layer 104 includes a first current blocking layer 1041 and a second current blocking layer 1042, which are located on the first epitaxial structure 11 and the second epitaxial structure 12, respectively.

[0173] The current blocking layer 104 includes a first current blocking layer 1041 and a second current blocking layer 1042, which are located on the first epitaxial structure 11 and the second epitaxial structure 12, respectively.

[0174] The transparent conductive layer 105 includes a first transparent conductive layer 1051 and a second transparent conductive layer 1052. The first transparent conductive layer 1051 and the second transparent conductive layer 1052 respectively cover the first current blocking layer 1041 and the second current blocking layer 1042, and are respectively connected to the first epitaxial structure 11 and the second epitaxial structure 12.

[0175] Optionally, the light-emitting diode also includes a passivation layer 107.

[0176] The passivation layer 107 covers the reflective layer 106 and the secondary electrode 30.

[0177] In this embodiment of the disclosure, the passivation layer may include 2 to 6 second vias 1002 and 1 to 3 third vias 1003.

[0178] For example, the passivation layer 107 includes four second vias 1002 and one third via 1003. The four second vias 1002 are grouped in pairs, and their projections on the bottom surface of the first epitaxial structure surround the first electrode 201 and the third electrode 203, respectively. The projection of the one third via 100 on the bottom surface of the second epitaxial structure 12 includes the fifth electrode 302.

[0179] In this implementation, the four-hole second through-hole can make the secondary electrode and the first electrode conductive, and the above arrangement can prevent current concentration.

[0180] In other embodiments, the passivation layer 107 may also include other numbers of second vias 1002 and third vias 1003. For example, six second vias 1002 and two third vias 1003.

[0181] In this embodiment, the second through hole 1002 is circular or elliptical, and the third through hole 1003 is a rounded rectangle.

[0182] In this implementation, because the size of the light-emitting diode is small, the opening area is limited when etching the via. Considering that the area of ​​the via needs to be as large as possible (the larger the area, the higher the conduction efficiency), the above-mentioned shape has the highest current conduction efficiency.

[0183] Optionally, the light-emitting diode also includes an electrode pad structure 40.

[0184] The electrode pad structure 40 includes a first electrode pad 401 and a second electrode pad 402. The first electrode pad 401 passes through the passivation layer 107 and is connected to the third electrode 301, and the second electrode pad 402 passes through the passivation layer 107 and is connected to the fifth electrode 303.

[0185] In the embodiments of this disclosure, the current blocking layer and the transparent conductive layer on the epitaxial structure can expand the current, avoid current concentration, optimize the current distribution, and effectively improve the luminous efficiency of the light-emitting diode; the passivation layer can provide protection for the light-emitting diode, avoid the influence of the external environment, and improve the yield of the light-emitting diode; the electrode pad structure can provide an electrical channel for the light-emitting diode to be electrically connected to the outside world.

[0186] In this embodiment of the disclosure, the substrate 100 can be any one of a sapphire substrate, a Si substrate, or a SiC substrate, and the material of the substrate 100 is not limited in this embodiment of the disclosure.

[0187] For example, substrate 100 is a sapphire substrate.

[0188] In this embodiment of the disclosure, the first semiconductor layer 101 can be an N-type semiconductor layer, and the second semiconductor layer 103 can be a P-type semiconductor layer.

[0189] For example, the first semiconductor layer 101 can be an N-type GaN layer, and the second semiconductor layer 103 can be a P-type GaN layer.

[0190] In this embodiment of the disclosure, the active layer 102 can be a multi-quantum well layer, for example, the active layer 102 is an InGaN / GaN multi-quantum well layer.

[0191] In other embodiments, the first semiconductor layer 101 may be a P-type semiconductor layer, and the second semiconductor layer 103 may be an N-type semiconductor layer.

[0192] In this embodiment of the disclosure, the current blocking layer 104 can be an AlGaN or SiO2 layer.

[0193] For example, the current blocking layer 104 is a SiO2 current blocking layer.

[0194] In this embodiment of the disclosure, the first transparent conductive layer 1051 and the second transparent conductive layer 1052 can be ITO layers. ITO has good transparency and conductivity, and can conduct current to form an electrical connection while light passes through.

[0195] In one example, the first transparent conductive layer 1051 and the second transparent conductive layer 1052 are full-surface non-perforated film layers.

[0196] In other examples, the first transparent conductive layer 1051 and the second transparent conductive layer 1052 can also be films with a perforated pattern. Reducing the ohmic contact between the transparent conductive layer and the epitaxial layer increases the current density of the chip, thereby increasing the chip's quantum efficiency and achieving a brighter appearance.

[0197] In this embodiment of the disclosure, the reflective layer 106 may be a distributed Bragg reflector (DBR) layer.

[0198] In this embodiment of the disclosure, the DBR layer can be a stack of alternating SiO2 and Ti3O5 layers.

[0199] In this embodiment of the disclosure, the alternation period of the SiO2 layer and the Ti3O5 layer can be 4 to 13 cycles.

[0200] For example, the alternation period of SiO2 layer and Ti3O5 layer can be 6 cycles.

[0201] In this embodiment, the passivation layer 107 can be SiO2, Si3N4, or SiN. x Or a SiON layer, where x is greater than 0.

[0202] For example, the passivation layer 107 is a SiO2 layer.

[0203] In this embodiment of the disclosure, the thickness of the passivation layer 107 can be 10,000 to 30,000 angstroms.

[0204] For example, the passivation layer 107 has a thickness of 20,000 angstroms.

[0205] In this embodiment of the disclosure, the third electrode 301, the fourth electrode 302 and the fifth electrode 303 can be stacked electrodes composed of at least two of Ti, Al, Pt and Ti.

[0206] For example, the third electrode 301, the fourth electrode 302 and the fifth electrode 303 are electrodes composed of Ti and Al.

[0207] In this embodiment of the disclosure, the first electrode pad 401 and the second electrode pad 402 can be Cr, Al, Ti, Ni, Pt or Au electrode pads.

[0208] Alternatively, the first electrode pad 401 and the second electrode pad 402 can be a stacked electrode composed of Ti, Al, Ni and Au.

[0209] For example, the first electrode pad 401 and the second electrode pad 402 are Cr electrodes.

[0210] In this embodiment of the disclosure, the light-emitting diode provided in this embodiment and the light-emitting diode provided by related technologies are subjected to full photoelectric performance testing and blue light packaging testing. After experimental verification, the brightness of the light-emitting diode provided in this embodiment of the disclosure is improved. The experimental data are shown in Table 1 below.

[0211] Table 1

[0212] In Table 1, WD represents the principal wavelength in nm; IV represents luminance in lm; ΔIV represents the percentage increase in luminance of the LED provided in this embodiment compared to LEDs provided in related technologies; Vf represents the forward operating voltage in V; ΔVf represents the increase in forward operating voltage of the LED provided in this embodiment compared to LEDs provided in related technologies. AVG represents the mean. As shown in Table 1, under various current conditions, through comparison among experimental samples in the same group, the LED provided in this embodiment effectively improves luminance.

[0213] Among them, Process 1 and Process 2 are two different manufacturing processes, and each process can serve as a control group, including 8 groups of control experiments. This disclosure does not limit the parameters of each process.

[0214] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: an epitaxial structure (10), a transparent conductive layer (105), a primary electrode (20), a reflective layer (106), and a secondary electrode (30). The epitaxial structure (10) has a groove (200), the primary electrode (20) is located at the bottom of the groove (200), the transparent conductive layer (105) is located on the surface of the epitaxial structure (10), the reflective layer (106) covers the epitaxial structure (10), the transparent conductive layer (105) and the primary electrode (20), the secondary electrode (30) passes through the reflective layer (106), and the secondary electrode (30) includes a portion that is in direct contact with the surface of the transparent conductive layer (105) and a portion that is in direct contact with the primary electrode (20).

2. The light-emitting diode according to claim 1, characterized in that, The primary electrode (20) is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum and gold.

3. The light-emitting diode according to claim 1, characterized in that, The secondary electrode (30) is in direct contact with the surface of the transparent conductive layer (105) through multiple contact points (31), and the area of ​​each of the multiple contact points (31) is smaller than the contact area between the primary electrode (20) and the bottom of the groove (200).

4. The light-emitting diode according to claim 3, characterized in that, The area of ​​each contact point (31) of the secondary electrode (30) is 77~81μm.

5. The light-emitting diode according to any one of claims 1 to 4, characterized in that, The epitaxial structure (10) is divided into a first epitaxial structure (11) and a second epitaxial structure (12) by an isolation groove (1000); the first epitaxial structure (11) has a first groove (2001), and the second epitaxial structure (12) has a second groove (2002). The primary electrode (20) includes a first electrode (201) and a second electrode (202), wherein the first electrode (201) is located in the first groove (2001) and the second electrode (202) is located in the second groove (2002); The secondary electrode (30) includes a third electrode (301), a fourth electrode (302) and a fifth electrode (303) located on the reflective layer (106). The third electrode (301) is electrically connected to the surface of the first epitaxial structure (11). The fourth electrode (302) extends from the first epitaxial structure (11) to the second epitaxial structure (12). One side of the fourth electrode (302) is electrically connected to the first electrode (201), and the other side of the fourth electrode (302) is electrically connected to the surface of the second epitaxial structure (12). The fifth electrode (303) is electrically connected to the second electrode (202).

6. A method for fabricating a light-emitting diode, characterized in that, The method includes: An epitaxial structure is fabricated, the epitaxial structure having a groove; A primary electrode is fabricated, the primary electrode being located at the bottom of the groove; A transparent conductive layer is fabricated on the surface of the epitaxial structure; A reflective layer is fabricated, which covers the epitaxial structure, the transparent conductive layer, and the primary electrode; A secondary electrode is fabricated, which passes through the reflective layer. The secondary electrode includes a portion that is in direct contact with the surface of the transparent conductive layer and a portion that is in direct contact with the primary electrode.

7. The method according to claim 6, characterized in that, The primary electrode is a metal stack composed of at least two of cadmium, aluminum, titanium, nickel, platinum, and gold.

8. The method according to claim 6, characterized in that, The secondary electrode is in direct contact with the surface of the transparent conductive layer through multiple contact points, and the area of ​​each of the multiple contact points is smaller than the contact area between the primary electrode and the bottom of the groove.

9. The method according to claim 8, characterized in that, The area of ​​each contact point of the secondary electrode is 77~81μm.

10. The method according to any one of claims 6 to 9, characterized in that, The epitaxial structure is divided into a first epitaxial structure and a second epitaxial structure by an isolation groove; the first epitaxial structure has a first groove, and the second epitaxial structure has a second groove; The primary electrode includes a first electrode and a second electrode, wherein the first electrode is located in the first groove and the second electrode is located in the second groove; The secondary electrode includes a third electrode, a fourth electrode, and a fifth electrode located on the reflective layer. The third electrode is electrically connected to the surface of the first epitaxial structure. The fourth electrode extends from the first epitaxial structure to the second epitaxial structure. One side of the fourth electrode is electrically connected to the first electrode, and the other side of the fourth electrode is electrically connected to the surface of the second epitaxial structure. The fifth electrode is electrically connected to the second electrode.

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