Light emitting diode and preparation method thereof
By covering the stepped sidewalls of the light-emitting diode with a protective layer, the leakage problem caused by the adhesion of conductive particles is solved, achieving higher reliability and performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-04-07
AI Technical Summary
Existing light-emitting diodes have the risk of leakage current, mainly due to the adhesion of conductive particles to the sidewalls of the steps, which leads to leakage failure.
A protective layer is applied to the sidewall of the light-emitting diode step. An aluminum oxide layer is formed by atomic layer deposition to cover the edge areas of the top and bottom surfaces of the step, preventing conductive particles from adhering and isolating the conductive particles during the fabrication of the transparent conductive layer.
This effectively prevents conductive particles from adhering to the sidewalls of the steps, enhances the isolation of conductive particles, prevents leakage failure, and improves the reliability and performance of the light-emitting diode.
Smart Images
Figure CN121815852A_ABST
Abstract
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 the same. Background Technology
[0002] A light-emitting diode (LED) is a semiconductor device that emits light.
[0003] The related technology provides a light-emitting diode, the light-emitting diode structure includes an epitaxial structure, a first electrode and a second electrode, the epitaxial structure includes a step top surface and a step bottom surface, and the first electrode and the second electrode are respectively located on the step top surface and the step bottom surface of the epitaxial structure.
[0004] The above-described light-emitting diodes have a risk of leakage. Summary of the Invention
[0005] This disclosure provides a light-emitting diode (LED) and its fabrication method, which can significantly improve the leakage current problem of LEDs. The technical solution is as follows: On the one hand, a light-emitting diode is provided, the light-emitting diode comprising: an epitaxial structure, a protective layer, a first electrode, and a second electrode; The epitaxial structure includes a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer; The first electrode is connected to the first semiconductor layer, and the second electrode is connected to the second semiconductor layer; The extension structure further includes a step structure, which includes a step top surface, a step bottom surface, and a step sidewall connecting the step top surface and the step bottom surface. The protective layer covers the step sidewall and covers the edge area of the step top surface and the edge area of the step bottom surface. The edge area is the area close to the step sidewall.
[0006] Optionally, the protective layer is an aluminum oxide layer.
[0007] Optionally, the width of the edge region of the top surface of the step covered by the protective layer is 3~5μm.
[0008] Optionally, the width of the edge region of the bottom surface of the step covered by the protective layer is 3~5μm.
[0009] Optionally, the thickness of the protective layer is 300 to 1200 angstroms.
[0010] Optionally, the light-emitting diode further includes a transparent conductive layer located on the top surface of the step, and the transparent conductive layer does not overlap with the protective layer.
[0011] Optionally, the distance between the protective layer and the transparent conductive layer is 0.5~3μm.
[0012] On the other hand, a method for fabricating a light-emitting diode is provided, the method comprising: An epitaxial structure is fabricated, the epitaxial structure comprising a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer; A stepped structure is fabricated on the epitaxial structure, the stepped structure including a step top surface, a step bottom surface, and a step sidewall connecting the step top surface and the step bottom surface; A protective layer is made that covers the sidewall of the step, and the protective layer covers the edge area of the top surface of the step and the edge area of the bottom surface of the step, wherein the edge area is the area close to the sidewall of the step.
[0013] Optionally, the width of the edge region of the top surface of the step covered by the protective layer is 3~5μm; The width of the edge region of the bottom surface of the step covered by the protective layer is 3~5μm.
[0014] Optionally, the fabrication of the protective layer includes: fabricating an alumina film layer using an atomic layer deposition process.
[0015] The beneficial effects of the technical solutions provided in this disclosure are: In this embodiment, the protective layer covers the sidewalls of the stepped structure, preventing conductive particles remaining from the patterning process of creating the conductive film layer (e.g., a transparent conductive layer) on the epitaxial structure from adhering to the sidewalls. Simultaneously, the protective layer also covers the edge regions of the top and bottom surfaces of the stepped structure, preventing conductive particles from the conductive film layer from contacting the sidewalls through the protective layer edges, further enhancing isolation from conductive particles. This design avoids the problem of conductive particles adhering to the sidewalls of the epitaxial structure due to the conductive film layer fabrication, thus preventing leakage current failure of the light-emitting diode. 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 (LED) according to an embodiment of the present disclosure. Figure 2This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure embodiment; Figure 3 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present disclosure; Figure 4 A top view of a light-emitting diode provided in an embodiment of this disclosure; Figure 5 A partially enlarged view of a light-emitting diode provided in an embodiment of this disclosure; Figure 6 A partial structural diagram of a light-emitting diode provided for related technologies.
[0018] The attached figures are labeled as follows: 10: Epitaxial structure; 20: Protective layer; 30: Insulating structure; 101: Substrate; 102: First semiconductor layer; 103: Active layer; 104: Second semiconductor layer; 105: Transparent conductive layer; 106: Dielectric film layer; 107: Metal reflective layer; 108: First electrode; 109: First electrode pad; 110: First insulating layer; 111: Second insulating layer; 112: Second electrode; 113: Second electrode pad; 114: Through-hole in the first insulating layer; 115: Through-hole in the second insulating layer; 116: Isolation trench; 117: Through-hole; 1000: Step structure; 1001: Top surface of the step; 1002: Bottom surface of the step; 1003: Side wall of the step; 2001: Conductive particles; L1: Width of the edge area of the top surface of the step covered by the protective layer; L2: Width of the edge area of the bottom surface of the step covered by the protective layer. 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, the epitaxial structure including a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer.
[0021] S12. A stepped structure is prepared on the extended structure, the stepped structure including a step top surface, a step bottom surface, and a step sidewall connecting the step top surface and the step bottom surface.
[0022] S13. Create a protective layer that covers the sidewall of the step, and the protective layer covers the edge area of the top surface of the step and the edge area of the bottom surface of the step, wherein the edge area is the area close to the sidewall of the step.
[0023] In this embodiment, the protective layer covers the sidewalls of the stepped structure, preventing conductive particles remaining from the patterning process of creating the conductive film layer (e.g., a transparent conductive layer) on the epitaxial structure from adhering to the sidewalls. Simultaneously, the protective layer also covers the edge regions of the top and bottom surfaces of the stepped structure, preventing conductive particles from the conductive film layer from contacting the sidewalls through the protective layer edges, further enhancing isolation from conductive particles. This design avoids the problem of conductive particles adhering to the sidewalls of the epitaxial structure due to the conductive film layer fabrication, thus preventing leakage current failure of the light-emitting diode.
[0024] Figure 2 A flowchart illustrating another 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 second semiconductor layer, the active layer, and the first semiconductor layer constitute an epitaxial structure.
[0025] The substrate can be any one of the following: a patterned sapphire substrate, a Si substrate, or a SiC substrate.
[0026] In one example, step S21 includes: The first step is to fabricate the first semiconductor layer.
[0027] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.
[0028] The second step is to create the active layer.
[0029] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.
[0030] The third step is to fabricate the second semiconductor layer.
[0031] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.
[0032] In this embodiment of the present disclosure, a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially stacked on a substrate.
[0033] S22. The extension structure is graphically processed to form a step structure, which includes a step top surface, a step bottom surface, and a step sidewall connecting the step top surface and the step bottom surface.
[0034] In this embodiment of the disclosure, the epitaxial structure is patterned by inductively coupled plasma etching (ICP).
[0035] In this embodiment of the disclosure, the first semiconductor layer, the active layer, and the second semiconductor layer are provided with a step structure extending to the first semiconductor, that is, the bottom surface of the step is located in the first semiconductor layer.
[0036] S23. A protective layer is made on the surface of the extension structure, the protective layer covers the sidewall of the step, and the protective layer covers the edge area of the top surface of the step and the edge area of the bottom surface of the step.
[0037] In one example, step S23 includes: The first step is to create a protective film on the surface of the epitaxial structure.
[0038] In this embodiment of the disclosure, an alumina thin film is fabricated using an atomic layer deposition process.
[0039] In this implementation, the atomic layer deposition process is used to fabricate alumina, which has good density and can form a dense protective layer on the sidewall of the step. This protects the sidewall of the step from the problem of conductive particles remaining on the sidewall of the step during the fabrication of the transparent conductive layer, which could lead to leakage failure of the light-emitting diode.
[0040] In other examples, other insulating materials, such as silicon oxide or silicon nitride, can also be used to form the thin film.
[0041] The second step involves fabricating a mask layer using photolithography. The mask layer covers the sidewalls of the step, and the protective layer covers the edge areas of the top and bottom surfaces of the step.
[0042] In this embodiment of the disclosure, fabricating the mask layer using photolithography may include: A photoresist film is fabricated on an alumina film, and the photoresist film is exposed and developed.
[0043] The fourth step is to remove the aluminum oxide film layer outside the mask layer by using the buffered oxide etching (BOE) process.
[0044] Fifth step: Remove the mask layer to obtain the protective layer.
[0045] In this embodiment of the disclosure, the width L1 of the edge region of the top surface of the step covered by the protective layer can be 3~5μm.
[0046] In this implementation, the width of the edge region of the top surface of the step covered by the protective layer is 3~5μm. Using this width range ensures that the width of the protective layer covering the top surface of the step is not too large, thus avoiding a reduction in the area of the transparent conductive layer and ensuring the current expansion capability of the light-emitting diode. Using this width range also ensures that the width of the protective layer covering the top surface of the step is not too small, thus preventing conductive particles from entering the sidewall of the epitaxial structure from the connection between the protective layer and the top surface of the step, thus ensuring the protective capability of the protective layer.
[0047] For example, the width L1 of the edge region of the top surface of the step covered by the protective layer is 4 μm.
[0048] In this embodiment of the disclosure, the width L2 of the edge region of the bottom surface of the step covered by the protective layer is 3~5μm.
[0049] In this implementation, the width of the edge region of the bottom surface of the step covered by the protective layer can be 3~5μm. Using this width range ensures that the width of the protective layer covering the top surface of the step is not too large, thus avoiding the step bottom surface area of the step structure being too small and preventing the voltage of the light-emitting diode from rising. Using this width range also ensures that the width of the protective layer covering the top surface of the step is not too small, thus avoiding the process window being insufficient and ensuring complete coverage of the sidewall of the step.
[0050] For example, the width L2 of the edge region of the bottom surface of the step covered by the protective layer is 4 μm.
[0051] In this embodiment of the disclosure, the thickness of the protective layer can be 300 to 1200 angstroms.
[0052] In this implementation, the thickness of the protective layer is 300~1200 angstroms. Using this thickness range ensures that the protective layer is not too thin, which would cause damage to the protective layer during the fabrication of the transparent conductive layer. Using this thickness range also ensures that the protective layer is not too thick, which would increase manufacturing costs and hinder the miniaturization design of the light-emitting diode.
[0053] For example, the thickness of the protective layer is 500 angstroms.
[0054] S24. Fabricate a transparent conductive layer.
[0055] In one example, step S24 includes: The first step is to fabricate a transparent conductive film on the surface of the epitaxial structure and the protective layer.
[0056] In this embodiment of the disclosure, the transparent conductive film can be an indium tin oxide (ITO) layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.
[0057] In this embodiment of the disclosure, the thickness of the transparent conductive film can be 170~250 angstroms. This thickness will not cause the ohmic contact and current spread of the second semiconductor layer to deteriorate due to being too thin, nor will it cause the film layer to absorb light and reduce the light extraction rate due to being too thick.
[0058] For example, the thickness of the transparent conductive film is 200 angstroms.
[0059] In this embodiment, the transparent conductive film is fabricated using a sputtering process. However, sputtering can easily cause conductive particles to remain and adhere to the sidewalls of the steps. Therefore, a protective layer is used to prevent these particles from adhering to the sidewalls and causing leakage failure of the LEDs.
[0060] The second step is to pattern the transparent conductive film to obtain a transparent conductive layer.
[0061] In this embodiment of the disclosure, the transparent conductive layer and the protective layer do not overlap, and the distance between the protective layer and the transparent conductive layer located on the top surface of the step is 0.5~3μm.
[0062] In this implementation, the distance between the protective layer and the transparent conductive layer on the top surface of the step is 0.5~3μm. This distance range ensures that the distance between the protective layer and the transparent conductive layer on the top surface of the step is not too large, thus avoiding the situation where the area of the transparent conductive layer is too small, which would reduce the brightness of the light-emitting diode. This distance range also ensures that the distance between the protective layer and the transparent conductive layer on the top surface of the step is not too small, thus avoiding the situation where the transparent conductive layer is difficult to etch, which could easily damage the protective layer and cause leakage of the light-emitting diode.
[0063] For example, the distance between the protective layer and the transparent conductive layer is 1.5 μm.
[0064] In other examples, the transparent conductive layer may also overlap with the edge of the protective layer.
[0065] S25. A dielectric film is fabricated on the transparent conductive layer, the dielectric film covering the protective layer, the epitaxial structure, the transparent conductive layer and the substrate.
[0066] In this embodiment of the disclosure, the dielectric film layer can be a SiO2 layer.
[0067] In this embodiment of the disclosure, plasma-enhanced chemical vapor deposition (PECVD) is used to fabricate the dielectric film layer.
[0068] In another embodiment, an optical coating machine is used to fabricate a dielectric film, which can be a stack of SiO2 and Ti3O5.
[0069] S26. Pattern the dielectric film to form through holes.
[0070] In this embodiment of the disclosure, through-holes in the dielectric film layer are formed by ICP etching, and the through-holes are formed in one step.
[0071] In this embodiment of the disclosure, the via includes a transparent conductive layer via and an epitaxial via.
[0072] The transparent conductive layer vias are provided corresponding to the transparent conductive layer, and the epitaxial vias are located on the bottom surface of the step of the epitaxial structure.
[0073] In this embodiment of the disclosure, the transparent conductive layer vias may include multiple vias that are spaced apart.
[0074] S27. Fabricate a metal reflective layer, which covers the dielectric film layer and is electrically connected to the transparent conductive layer inside the through hole.
[0075] In this embodiment, the metal reflective layer is a silver mirror layer, which can be a combination of one or more metal or alloy layers such as Ag, Ni, Ti, TiW, Al, AlCu, Ti, Ni, Pt, and Au. Ag is the main structure, serving to reflect light and spread current, while Ni and TiW prevent the migration and diffusion of Ag.
[0076] For example, the metal reflective layer is a stack of Ag, Ni, Ti and TiW.
[0077] S28. Make the first insulating layer.
[0078] In one example, step S28 includes: The first step is to fabricate the first insulating film layer, which covers the metal reflective layer and the dielectric film layer.
[0079] The first insulating film layer can be a distributed Bragg reflector (DBR) layer or a SiO2 layer, with the DBR layer being a stack of SiO2 and Ti3O5.
[0080] The second step is to pattern the first insulating film layer and open through holes in the first insulating layer at the stepped structure and the metal reflective layer to form the first insulating layer.
[0081] In this embodiment of the disclosure, the first insulating layer via is formed by wet etching or dry etching.
[0082] S29. Fabricate a first electrode and a second electrode. The first electrode is connected to the metal reflective layer through a through-hole in the first insulating layer at the metal reflective layer, and the second electrode is connected to the epitaxial structure through a through-hole in the first insulating layer at the stepped structure.
[0083] In the embodiments of this disclosure, the first electrode and the second electrode can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.
[0084] For example, the first electrode and the second electrode are a stack of Cr, Al, AlCu, Ti, Ni, Pt and Au.
[0085] S30, Make the second insulating layer.
[0086] In one example, step S29 includes: The first step is to fabricate a second insulating film layer, which covers the first electrode, the second electrode, and the first insulating layer.
[0087] The second insulating film layer can be a DBR layer or a SiO2 layer, where the DBR layer is a stack of SiO2 and Ti3O5.
[0088] The second step is to pattern the second insulating film layer and open through holes in the second insulating layer at the first electrode and the second electrode.
[0089] In this embodiment of the disclosure, a second insulating layer via is formed by wet etching or dry etching.
[0090] For example, the wet etching process for creating through-holes in the first and second insulating layers is relatively simple, low-cost, and has good isotropy, allowing for uniform through-hole formation.
[0091] S31. Fabricate a first electrode pad and a second electrode pad. The first electrode pad is connected to the first electrode through a second insulating layer through-hole at the first electrode, and the second electrode pad is connected to the second electrode through a second insulating layer through-hole at the second electrode.
[0092] In this embodiment of the disclosure, the first electrode pad and the second electrode pad can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt, Au and AuSn.
[0093] For example, the first electrode pad and the second electrode pad are Cr, Al, AlCu, Ti, Ni, Pt, Au and AuSn stacks.
[0094] Figure 3 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 3 The light-emitting diode includes: Epitaxial structure 10 and protective layer 20, first electrode 108 and second electrode 112.
[0095] The epitaxial structure 10 includes a first semiconductor layer 102, a second semiconductor layer 104, and an active layer 103 disposed between the first semiconductor layer 102 and the second semiconductor layer 104.
[0096] The first electrode 108 is connected to the first semiconductor layer 102, and the second electrode 112 is connected to the second semiconductor layer 103.
[0097] The extension structure 10 includes a step structure 1000, which includes a step top surface 1001, a step bottom surface 1002, and a step sidewall 1003 connecting the step top surface 1001 and the step bottom surface 1002. The protective layer 20 covers the step sidewall 1003, and the protective layer 20 covers the edge area of the step top surface 1001 and the edge area of the step bottom surface 1002. The edge area is the area close to the step sidewall 1003.
[0098] In this embodiment, the protective layer covers the sidewalls of the stepped structure, preventing conductive particles remaining from the patterning process of creating the conductive film layer (e.g., a transparent conductive layer) on the epitaxial structure from adhering to the sidewalls. Simultaneously, the protective layer also covers the edge regions of the top and bottom surfaces of the stepped structure, preventing conductive particles from the conductive film layer from contacting the sidewalls through the protective layer edges, further enhancing isolation from conductive particles. This design avoids the problem of conductive particles adhering to the sidewalls of the epitaxial structure due to the conductive film layer fabrication, thus preventing leakage current failure of the light-emitting diode.
[0099] Figure 4 This is a top view of a light-emitting diode provided as an embodiment of the present disclosure. See also: Figure 4 The stepped structure 1000 is a whole surface structure, and the protective layer 20 covers the stepped structure 1000.
[0100] In this embodiment of the disclosure, the protective layer 20 can be an alumina layer fabricated by atomic layer deposition process.
[0101] In this implementation, aluminum oxide can form a dense protective layer on the sidewall of the step, which can protect the sidewall of the step and prevent the etching residue of the transparent conductive layer from adhering to the sidewall of the step during the subsequent fabrication of the transparent conductive layer, thus avoiding the problem of leakage failure of the light-emitting diode.
[0102] In this embodiment of the disclosure, the thickness of the protective layer 20 can be 300 to 1200 angstroms.
[0103] In this implementation, the thickness of the protective layer is 300~1200 angstroms. Using this thickness range ensures that the protective layer is not too thin, which would cause damage to the protective layer during the fabrication of the transparent conductive layer. Using this thickness range also ensures that the protective layer is not too thick, which would increase manufacturing costs and hinder the miniaturization design of the light-emitting diode.
[0104] For example, the thickness of the protective layer 20 is 500 angstroms.
[0105] Figure 5 This is a partially enlarged view of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 5 The width L1 of the edge region of the top surface 1001 of the step covered by the protective layer 20 can be 3~5μm.
[0106] In this implementation, the width of the edge region of the top surface of the step covered by the protective layer is 3~5μm. Using this width range ensures that the width of the protective layer covering the top surface of the step is not too large, thus avoiding a reduction in the area of the transparent conductive layer and ensuring the current expansion capability of the light-emitting diode. Using this width range also ensures that the width of the protective layer covering the top surface of the step is not too small, thus preventing conductive particles from entering the sidewall of the epitaxial structure from the connection between the protective layer and the top surface of the step, thus ensuring the protective capability of the protective layer.
[0107] Figure 6 A partial structural diagram of a light-emitting diode (LED) provided for related technologies. See also... Figure 6 The stepped sidewall 1003 of the epitaxial structure 10 is not covered by a protective layer, and the conductive particles 2001 adhere to the stepped sidewall 1003, causing the light-emitting diode to leak.
[0108] For example, the width L1 of the edge region of the top surface 1001 of the step covered by the protective layer 20 is 4 μm.
[0109] In this embodiment of the disclosure, the width L2 of the edge region of the bottom surface 1002 of the step covered by the protective layer 20 is 3~5μm.
[0110] In this implementation, the width of the edge region of the bottom surface of the step covered by the protective layer can be 3~5μm. Using this width range ensures that the width of the protective layer covering the top surface of the step is not too large, thus avoiding the step bottom surface area of the step structure being too small and preventing the voltage of the light-emitting diode from rising. Using this width range also ensures that the width of the protective layer covering the top surface of the step is not too small, thus avoiding the process window being insufficient and ensuring complete coverage of the sidewall of the step.
[0111] For example, the width L2 of the edge region of the step bottom surface 1002 covered by the protective layer 20 is 4 μm.
[0112] In this embodiment of the disclosure, the light-emitting diode further includes a transparent conductive layer 105, which is located on the top surface 1001 of the step.
[0113] In this embodiment of the disclosure, the transparent conductive layer 105 can be an ITO layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.
[0114] In this embodiment, the thickness of the transparent conductive layer 105 can be 170 to 250 angstroms. This thickness will not cause the ohmic contact and current spread of the second semiconductor layer to deteriorate due to being too thin, nor will it cause the film layer to absorb light and reduce the light extraction rate due to being too thick.
[0115] For example, the thickness of the transparent conductive layer 105 is 200 angstroms.
[0116] In this embodiment of the disclosure, the transparent conductive layer 105 and the protective layer 20 do not overlap, and the distance between the protective layer 20 and the transparent conductive layer 105 located on the top surface 1001 of the step is 0.5~3μm.
[0117] In this implementation, the distance between the protective layer and the transparent conductive layer on the top surface of the step is 0.5~3μm. This distance range ensures that the distance between the protective layer and the transparent conductive layer on the top surface of the step is not too large, thus avoiding the situation where the area of the transparent conductive layer is too small, resulting in a decrease in the brightness of the light-emitting diode. This distance range also ensures that the distance between the protective layer and the transparent conductive layer on the top surface of the step is not too small, thus avoiding the situation where the transparent conductive layer is difficult to etch, easily damaging the protective layer and causing leakage of the light-emitting diode.
[0118] For example, the distance between the protective layer 20 and the transparent conductive layer 105 is 1.5 μm.
[0119] See you again Figure 3 The light-emitting diode may also include: Dielectric film layer 106 and metal reflective layer 107; The dielectric film layer 106 covers the transparent conductive layer 105. The dielectric film layer 106 has a plurality of through holes 117, including transparent conductive layer through holes and epitaxial through holes. The transparent conductive layer through holes are correspondingly arranged with the transparent conductive layer. The epitaxial through holes are located on the bottom surface of the step of the epitaxial structure. The bottom of the transparent conductive layer through holes is located on the surface of the transparent conductive layer 105. The metal reflective layer 107 covers the dielectric film layer 106 and is electrically connected to the transparent conductive layer 105 in the through holes 117.
[0120] In this embodiment of the present disclosure, the projection of the through hole 117 onto the surface of the epitaxial structure 10 is circular.
[0121] In this embodiment of the disclosure, the dielectric film layer 106 may be a SiO2 layer or a stack formed of SiO2 and Ti3O5.
[0122] In this embodiment, the metal reflective layer 107 is a silver mirror layer, and the metal reflective layer 107 can be a combination of one or more metal or alloy layers such as Ag, Ni, Ti, TiW, Al, AlCu, Ti, Ni, Pt, and Au. Among them, metal Ag is the main structure, which plays the role of light reflection and current spread, while Ni and TiW play the role of preventing the migration and diffusion of metal Ag.
[0123] For example, the metal reflective layer 107 is a stack of Ag, Ni, Ti and TiW.
[0124] In this embodiment of the disclosure, the light-emitting diode may further include: a substrate 101, a first electrode pad 109, a second electrode pad 113, and an insulating structure 30.
[0125] For example, the insulating structure 30 includes a first insulating layer 110 and a second insulating layer 111.
[0126] The first semiconductor layer 102, the active layer 103, and the second semiconductor layer 104 have a stepped structure 1000 extending to the first semiconductor layer 102. The bottom surface 1002 of the stepped structure 1000 is located in the first semiconductor layer 102, and the isolation trench 116 is located in the substrate 101.
[0127] The first insulating layer 110 covers the metal reflective layer 107 and the dielectric film layer 106. The first insulating layer 110 has through holes 114 at the metal reflective layer 107 and the stepped structure 1000, respectively. The first electrode 108 is connected to the metal reflective layer 107 through the through holes 114 at the metal reflective layer 107. The second electrode 112 is connected to the epitaxial structure 10 (first semiconductor layer 102) through the through holes 114 at the stepped structure 1000.
[0128] The second insulating layer 111 covers the second electrode 112 and the first insulating layer 110. The second insulating layer 111 has through holes 115 at the first electrode 108 and the second electrode 112 respectively. The first electrode pad 109 is connected to the first electrode 108 through the through hole 115 at the first electrode 108. The second electrode pad 113 is connected to the second electrode 112 through the through hole 115 at the second electrode 112.
[0129] In this embodiment of the disclosure, the substrate 101 can be any one of a sapphire patterned substrate, a Si substrate, or a SiC substrate, and the material of the substrate 101 is not limited in this embodiment of the disclosure.
[0130] For example, substrate 101 is a patterned sapphire substrate.
[0131] In this embodiment of the disclosure, the first semiconductor layer 102 can be an N-type semiconductor layer, and the second semiconductor layer 104 can be a P-type semiconductor layer.
[0132] For example, the first semiconductor layer 102 can be an N-type GaN layer, and the second semiconductor layer 104 can be a P-type GaN layer.
[0133] In other embodiments, the first semiconductor layer 102 may be a P-type semiconductor layer, and the second semiconductor layer 104 may be an N-type semiconductor layer.
[0134] In this embodiment of the disclosure, the active layer 103 can be a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.
[0135] In this embodiment of the disclosure, the first electrode 108 and the second electrode 112 can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.
[0136] For example, the first electrode 108 and the second electrode 112 are Cr, Al, AlCu, Ti, Ni, Pt and Au stacks.
[0137] In this embodiment of the disclosure, the first electrode pad 109 and the second electrode pad 113 can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt, Au and AuSn.
[0138] For example, the first electrode pad 109 and the second electrode pad 113 are Cr, Al, AlCu, Ti, Ni, Pt, Au and AuSn stacks.
[0139] In this embodiment of the present disclosure, the first insulating layer 110 and the second insulating layer 111 can be a DBR layer or a SiO2 layer, wherein the DBR layer is a stack formed of SiO2 and Ti3O5.
[0140] It is worth noting that, in the embodiments of this disclosure, the structure can be selectively added or reduced based on the structure of the light-emitting diode described above, and this disclosure does not limit this.
[0141] 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 protective layer (20), a first electrode (108), and a second electrode (112); The epitaxial structure (10) includes a first semiconductor layer (102), a second semiconductor layer (104), and an active layer (103) disposed between the first semiconductor layer (102) and the first semiconductor layer (104). The first electrode (108) is connected to the first semiconductor layer (102), and the second electrode (112) is connected to the second semiconductor layer (103). The extension structure (10) further includes a step structure (1000), the step structure (1000) includes a step top surface (1001), a step bottom surface (1002) and a step sidewall (1003) connecting the step top surface (1001) and the step bottom surface (1002), the protective layer (20) covers the step sidewall (1003), and the protective layer (20) covers the edge area of the step top surface (1001) and the edge area of the step bottom surface (1002), the edge area being the area close to the step sidewall (1003).
2. The light-emitting diode according to claim 1, characterized in that, The protective layer (20) is an aluminum oxide layer.
3. The light-emitting diode according to claim 2, characterized in that, The width of the edge region of the top surface (1001) of the step covered by the protective layer (20) is 3~5μm.
4. The light-emitting diode according to claim 3, characterized in that, The width of the edge region of the bottom surface (1002) of the step covered by the protective layer (20) is 3~5μm.
5. The light-emitting diode according to claim 4, characterized in that, The thickness of the protective layer (20) is 300~1200 angstroms.
6. The light-emitting diode according to any one of claims 1 to 5, characterized in that, The light-emitting diode further includes a transparent conductive layer (105), which is located on the top surface (1001) of the step and does not overlap with the protective layer (20).
7. The light-emitting diode according to claim 6, characterized in that, The distance between the protective layer (20) and the transparent conductive layer (105) is 0.5~3μm.
8. A method for fabricating a light-emitting diode, characterized in that, The method includes: An epitaxial structure is fabricated, the epitaxial structure comprising a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer; A stepped structure is fabricated on the epitaxial structure, the stepped structure including a step top surface, a step bottom surface, and a step sidewall connecting the step top surface and the step bottom surface; A protective layer is made that covers the sidewall of the step, and the protective layer covers the edge area of the top surface of the step and the edge area of the bottom surface of the step, wherein the edge area is the area close to the sidewall of the step.
9. The method for fabricating a light-emitting diode according to claim 8, characterized in that, The width of the edge region of the top surface of the step covered by the protective layer is 3~5μm; The width of the edge region of the bottom surface of the step covered by the protective layer is 3~5μm.
10. The method for fabricating a light-emitting diode according to claim 8 or 9, characterized in that, The fabrication of the protective layer includes: fabricating an alumina film layer using an atomic layer deposition process.