Light emitting diode and preparation method thereof

Abstract

The invention discloses a light-emitting diode and a preparation method thereof, and relates to the technical field of semiconductors. The light-emitting diode comprises a substrate and an N-type layer, a multi-quantum well layer, a P-type layer, a current expansion layer, a composite layer, a metal reflection layer and an insulating layer which are sequentially arranged on the substrate, the upper surface of the insulating layer is etched downwards to form connecting holes which are respectively exposed out of the N-type layer and connected with the current expansion layer, and the insulating layer covers the side walls of the connecting holes. Metal is filled in the connecting holes to serve as N-pole metal and P-pole metal, the N-pole metal is connected with the N-type layer, and the P-pole metal is connected with the P-type layer through the current expansion layer. According to the light-emitting diode and the preparation method thereof, the reliability of the light-emitting diode can be improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a light-emitting diode and a method for fabricating the same. Background Technology

[0002] Light-emitting diodes (LEDs), as the core light source for next-generation solid-state lighting and displays, are widely used in general lighting, automotive lighting, and backlight modules due to their high energy efficiency, long lifespan, and environmental friendliness. However, limited by the high refractive index of gallium nitride (GaN)-based materials, most photons generated inside the LED chip are confined within the chip during emission due to total internal reflection, ultimately being absorbed and converted into heat energy, resulting in a significant reduction in overall light extraction efficiency. Studies show that while the theoretical external quantum efficiency of traditional blue LED chips can exceed 80%, the actual light extraction efficiency is often less than 30%. To improve light extraction efficiency, the industry commonly uses the deposition of transparent conductive oxides on a p-type GaN layer to improve current spread, and then integrates a high-reflectivity metal layer on top to reflect downward-propagating photons back to the emission direction. Among many candidate metals, silver is considered an ideal reflective electrode material due to its high reflectivity (over 95%) in the blue light band, excellent thermal conductivity, and low sheet resistance.

[0003] However, Ag presents significant reliability risks in LED chip applications. First, silver atoms are highly susceptible to migration under high temperature or high current stress, leading to metal layer morphology degradation and even the formation of conductive filaments, causing short circuits or leakage. Second, silver is chemically reactive and easily undergoes oxidation or sulfidation reactions in humid, sulfur-containing environments, resulting in decreased reflectivity and increased contact resistance, thereby accelerating light decay and shortening device lifespan. Furthermore, the interfacial adhesion between Ag and GaN or transparent conductive oxides is weak, making them prone to delamination and peeling failure modes under thermal cycling or mechanical stress, severely impacting the long-term stability of the chip. Summary of the Invention

[0004] The purpose of this application is to provide a light-emitting diode and a method for fabricating the same, which can improve the reliability of the light-emitting diode.

[0005] The embodiments of this application are implemented as follows: A first aspect of this application provides a light-emitting diode, including a substrate and an N-type layer, a multiple quantum well layer, a P-type layer, a current spreading layer, a composite layer, a metal reflective layer, and an insulating layer sequentially disposed on the substrate. A connection hole is formed by etching downward from the upper surface of the insulating layer, exposing the connection between the N-type layer and the current spreading layer. The insulating layer covers the sidewalls of the connection hole. The connection hole is filled with metal as the N-type metal and the P-type metal. The N-type metal is connected to the N-type layer, and the P-type metal is connected to the P-type layer through the current spreading layer.

[0006] In one possible implementation, multiple filling holes are formed on the composite layer, and a metal reflective layer is disposed on the upper surface of the composite layer, or the metal reflective layer extends to the filling holes and connects with the current spreading layer, or the metal reflective layer fills the filling holes.

[0007] As one feasible approach, the composite layer includes a current blocking layer combined with a DBR reflective layer.

[0008] As one possible implementation, the metal reflective layer includes a silver layer, a titanium layer, and a nickel layer disposed sequentially.

[0009] As one possible implementation, an N-type ohmic contact block is also provided between the N-electrode metal and the N-type layer, and the N-electrode metal wraps around the N-type ohmic contact block.

[0010] As one possible implementation, the connection hole includes multiple P-type holes and multiple N-type holes. The current spreading layer is exposed through the P-type holes, the N-type layer is exposed through the N-type holes, the multiple N-type holes are arranged in an array, and each N-type hole is surrounded by at least 4 P-type holes.

[0011] As one possible implementation, the N-type aperture is formed by connecting a first through-hole on the metal reflective layer, a second through-hole on the DBR reflective layer, and a third through-hole on the current blocking layer; the diameter of the first through-hole is larger than the diameters of the second and third through-holes.

[0012] As one possible implementation, the insulating layer comprises aluminum oxide and silicon dioxide stacked sequentially.

[0013] As one possible implementation, the diameter of the connecting hole is between 10μm and 50μm, and the distance between two adjacent connecting holes is between 50μm and 300μm.

[0014] As one possible implementation, the N-polar metal and the P-polar metal have the same structure, which is a Cr / Ag / Ti / Al / Ti structure.

[0015] A second aspect of this application provides a method for fabricating a light-emitting diode (LED), comprising: sequentially depositing an N-type layer, a multiple quantum well layer, a P-type layer, and a current spreading layer on the upper surface of a substrate; etching the current spreading layer, the P-type layer, and the multiple quantum well layer on the upper surface of the current spreading layer to expose the N-type layer and form a plurality of N-type sub-vias; forming a composite structure on the current spreading layer, the composite structure comprising a current blocking layer and / or a DBR reflective layer, a metal reflective layer, and an insulating layer sequentially disposed thereon, forming a plurality of through-holes and a plurality of P-type holes on the composite structure, the plurality of N-type sub-vias corresponding to and connected to the plurality of through-holes to form N-type holes, the N-type layer being exposed through the N-type holes, and the current spreading layer being exposed through the P-type holes; filling the P-type holes and N-type holes with metal to form N-electrode metal and P-electrode metal.

[0016] As one possible implementation, forming a composite structure on a current spreading layer includes: setting a composite layer on the current spreading layer, the composite layer including a current blocking layer and / or a DBR reflective layer; forming a metal reflective layer on the composite layer and etching to form a plurality of first sub-vias, wherein some of the first sub-vias are connected to N-type sub-vias; setting an insulating layer on the metal reflective layer and etching to form a plurality of second sub-vias, the second sub-vias being connected to the first sub-vias one-to-one to form through holes, wherein some of the through holes are connected to the N-type sub-vias as through holes to form N-type holes, the remaining through holes are P-type holes, the N-type layer is exposed through the N-type holes, the current spreading layer is exposed through the P-type holes, and the insulating layer covers the sidewalls of the through holes.

[0017] As one possible implementation, forming a composite structure on a current spreading layer includes: sequentially disposing a composite layer, a metal reflective layer, and an insulating layer on the current spreading layer, wherein the composite layer includes a current blocking layer and / or a DBR reflective layer; etching to form multiple through holes, wherein some of the through holes serve as vias connected to N-type sub-holes to form N-type holes, and the remaining through holes serve as P-type holes; and forming an insulating sidewall connected to the insulating layer on the sidewall of the through holes.

[0018] As one possible implementation, a metal reflective layer is formed on the composite layer and a plurality of first sub-holes are etched, including: a current blocking layer and a DBR reflective layer as the composite layer, etching the composite layer to form a plurality of filling holes on the composite layer; a metal reflective layer is formed on the composite layer, the metal reflective layer extends to the filling holes and connects with the current spreading layer, or the metal reflective layer fills the filling holes.

[0019] The beneficial effects of the embodiments of this application include: The light-emitting diode (LED) provided in this application includes a substrate and an N-type layer, a multiple quantum well layer, a P-type layer, a current spreading layer, a composite layer, a metal reflective layer, and an insulating layer sequentially disposed on the substrate. A connection hole is formed by etching downwards from the upper surface of the insulating layer, exposing the connection between the N-type layer and the current spreading layer. The insulating layer covers the sidewalls of the connection hole, ensuring that the metal reflective layer is completely encapsulated between the LED and the insulating layer. This prevents the metal reflective layer from being electrically connected to the P-type metal, meaning it only participates in reflection and not in the current injection of the PN junction. Thus, even if the metal reflective layer contains silver, it does not contact the electrode metal. The insulating layer on the sidewalls of the connection hole physically blocks the contact between silver and the electrode metal. Even at high temperatures or high currents, silver ions cannot migrate along the hole walls to the PN junction or electrode, preventing short circuits or leakage and eliminating ion migration. The complete coverage of the insulating layer forms a dense protective layer, effectively isolating external moisture, oxygen, and sulfides, significantly delaying silver layer deterioration, maintaining long-term high reflectivity, and improving the stability of the LED, thereby enhancing its reliability. The connecting holes are filled with metal as the N-type and P-type metals, with the N-type metal connected to the N-type layer and the P-type metal connected to the P-type layer. The N-type and P-type metals are directly connected through the connecting hole structure, resulting in low contact resistance. Therefore, the light-emitting diode of this embodiment can improve the reliability of the light-emitting diode. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is one of the structural schematic diagrams of a light-emitting diode provided in the embodiments of this application; Figure 2 This is a second schematic diagram of the structure of a light-emitting diode provided in an embodiment of this application; Figure 3 This is the third schematic diagram of the structure of a light-emitting diode provided in the embodiments of this application; Figure 4 This is the fourth schematic diagram of the structure of a light-emitting diode provided in the embodiments of this application; Figure 5 One of the layout diagrams of the silver reflective layer of a light-emitting diode provided in an embodiment of this application; Figure 6 A second layout diagram of the silver reflective layer of the light-emitting diode provided in the embodiments of this application; Figure 7 The third layout diagram of the silver reflective layer of the light-emitting diode provided in the embodiments of this application; Figure 8 The fourth layout diagram of the silver reflective layer of the light-emitting diode provided in the embodiments of this application; Figure 9 A top perspective view of a light-emitting diode provided in an embodiment of this application; Figure 10 A flowchart illustrating the fabrication method of a light-emitting diode provided in this application embodiment; Figure 11 This is one of the state diagrams for a method of fabricating a light-emitting diode provided in an embodiment of this application; Figure 12 The second state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 13 The third state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 14 The fourth state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 15 The fifth state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 16 The sixth state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 17 The seventh state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 18 This is the eighth state diagram of the method for fabricating a light-emitting diode provided in the embodiments of this application; Figure 19 The ninth state diagram for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 20 The tenth state diagram is for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 21 Eleventh of the state diagrams for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 22 The twelfth state diagram is for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 23 The thirteenth state diagram is for the fabrication method of the light-emitting diode provided in the embodiments of this application; Figure 24 This is the fourteenth state diagram of the method for fabricating a light-emitting diode provided in the embodiments of this application.

[0022] Icons: 100 - Light Emitting Diode; 110 - Substrate; 120 - N-type Layer; 130 - Multiple Quantum Well Layer; 140 - P-type Layer; 150 - Current Spreading Layer; 160 - Current Blocking Layer; 170 - DBR Reflective Layer; 180 - Metal Reflective Layer; 190 - Insulating Layer; 210 - N-type Metal; 220 - P-type Metal; 510 - N-type Ohmic Contact Block; 610 - N-type Hole; 611 - N-type Sub-hole; 620 - P-type Hole; 710 - Ppad; 720 - Npad; 730 - Isolating Layer. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of this application, not all embodiments. Similar reference numerals and letters in the following drawings indicate similar items. Once an item is defined in one drawing, it does not need to be further defined in other drawings.

[0024] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and should not be construed as limiting this application. The terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to connections within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0026] Please refer to the reference. Figures 1 to 4 This application provides a light-emitting diode 100, including a substrate 110 and an N-type layer 120, a multiple quantum well layer 130, a P-type layer 140, a current spreading layer 150, a composite layer, a metal reflective layer 180, and an insulating layer 190 sequentially disposed on the substrate 110. A connection hole is formed by etching downward from the upper surface of the insulating layer 190, exposing the connection between the N-type layer 120 and the current spreading layer 150. The insulating layer 190 covers the sidewalls of the connection hole. The connection hole is filled with metal as N-type metal 210 and P-type metal 220. The N-type metal 210 is connected to the N-type layer 120, and the P-type metal 220 is connected to the P-type layer 140 through the current spreading layer 150.

[0027] When the light-emitting diode 100 of this embodiment is operating, if a forward voltage is applied between the N-type metal 210 and the P-type metal 220, electrons are injected from the N-type layer 120 and holes are injected from the P-type layer 140. These electrons recombine in the multi-quantum-well layer 130. The energy released by carrier recombination is radiated in the form of photons. Since the multi-quantum-well is located between the P-type layer 140 and the N-type layer 120, some light is emitted upwards and some propagates downwards. The upward-propagating light is first reflected by the composite layer and then reflected a second time by the metal reflective layer 180, causing most of the light to propagate downwards and be emitted, significantly improving light extraction efficiency. Specifically, the composite layer includes a DBR reflective layer. The DBR reflective layer 170 has a high reflectivity when incident vertically, but its reflection effect is slightly worse when grazing at large angles. Although the overall reflectivity of the metal reflective layer 180 is lower, its reflectivity is well maintained at various angles, which can compensate for the shortcomings of the DBR's oblique angle incident reflection, thereby improving reflectivity, preventing light leakage, and improving luminous efficiency.

[0028] The current spreading layer 150 ensures uniform current distribution in the P region; the N-metal 210 and P-metal 220 are directly connected to each other through a connecting hole structure, resulting in low contact resistance.

[0029] The connecting hole sidewall is covered by an insulating layer 190, which completely encapsulates the metal reflective layer 180 between the DBR and the insulating layer 190. This prevents the metal reflective layer 180 from being electrically connected to the P-electrode metal 220. In other words, the metal reflective layer 180 only participates in reflection and not in the current injection of the PN junction. Thus, even if the metal reflective layer 180 contains silver, it does not come into contact with the electrode metal. The insulating layer 190 on the connecting hole sidewall physically blocks the contact between silver and the electrode metal. Even at high temperatures or high currents, silver ions cannot migrate along the hole wall to the PN junction or electrode, avoiding short circuits or leakage and preventing ion migration. The insulating layer 190 forms a dense protective layer that fully covers the area, effectively isolating external moisture, oxygen, and sulfides, significantly delaying the deterioration of the silver layer, maintaining long-term high reflectivity, and improving the stability of the light-emitting diode 100, thereby improving the reliability of the light-emitting diode 100.

[0030] In addition, this embodiment retains the high reflectivity of the metal reflective layer 180 and combines it with the DBR reflective layer 170 to form a composite reflective structure, which significantly improves the light extraction efficiency. Furthermore, the P-type metal 220 and the N-type metal 210 directly contact the P-type layer 140 and the N-type layer 120, respectively, resulting in low contact resistance and low thermal resistance. Therefore, the light-emitting diode 100 in this embodiment can maintain high luminous efficiency and electrical performance.

[0031] In practical applications, such as Figure 23 and Figure 24As shown, an isolation layer 730 can also be provided on the P-metal 220, N-metal 210, and insulating layer 190. A Ppad 710 and an Npad 720, respectively connected to the P-metal 220 and N-metal 210, are provided on the isolation layer 730, as shown. Figure 2 As shown. The isolation layer 730 can be formed by stacking two materials, alumina and silicon oxide. Specifically, the thickness of the alumina is 1250 angstroms, the thickness of the silicon oxide is 4000 angstroms, and the thickness of the isolation layer 730 is 6250 angstroms.

[0032] Specifically, the materials used in each layer of this application are not limited. For example, substrate 110, serving as the basis for epitaxial growth, can be sapphire, silicon carbide, or silicon substrate 110; N-type layer 120 and P-type layer 140 are used to form a PN junction and current channel, and can be formed after gallium nitride doping. Current spreading layer 150 is used to uniformly distribute the P-region current laterally, and can be an indium tin oxide transparent conductive layer; metal reflective layer 180 is made of a high-reflectivity metal, such as silver or aluminum. Insulating layer 190 covers the surface and serves as passivation and isolation, and can be silicon dioxide or aluminum oxide.

[0033] Optional, such as Figure 2 , Figure 3 and Figure 4 As shown, multiple filling holes are formed on the composite layer, and a metal reflective layer 180 is disposed on the upper surface of the composite layer, or the metal reflective layer 180 extends to the filling holes and connects with the current spreading layer 150, or the metal reflective layer 180 fills the filling holes.

[0034] The operating current is injected from the metal pad in the top P-type connection hole and diffuses laterally to the entire P-type layer 140 through the current spreading layer 150; the metal reflective layer 180 itself does not serve as the main current path and is only in a floating or auxiliary contact state.

[0035] The composite layer forms multiple filling holes, allowing the metal reflective layer 180 to extend into these holes and connect with the current spreading layer 150. This allows for more metal reflective layers 180 to be disposed close to the current spreading layer 150, increasing the contact area between the metal reflective layer 180 and the current spreading layer 150. This improves the adhesion of the metal reflective layer 180, thereby enhancing its stability, as silver, when the metal reflective layer 180 is made of silver, allows for excellent contact with the current spreading layer 150. Furthermore, it allows more light beams to initially contact the metal reflective layer 180, thus improving reflectivity. Additionally, it relieves stress on the metal reflective layer, further enhancing its stability.

[0036] In summary, while retaining the high reflectivity of silver, the non-conductive filled-hole structure significantly enhances the mechanical bonding and thermal coupling between the metal reflective layer 180 and the underlying layer, fundamentally alleviating reliability concerns such as silver's easy migration, oxidation, and poor adhesion. Simultaneously, the composite layer and the top insulating layer 190 together form a tightly sealed packaging environment, isolating external corrosion and enabling the device to possess both high luminous efficiency and long-term stability.

[0037] In other embodiments, openings may be made in the current spreading layer 150 so that the metal reflective layer 180 can directly contact the P-type layer 140.

[0038] As one feasible approach, the composite layer includes a current blocking layer combined with a DBR reflective layer.

[0039] The current blocking layer 160 prevents current from diffusing into the non-light-emitting area, improving light emission uniformity and efficiency. The current blocking layer 160 is used to limit the current to only pass through the designed light-emitting area, thereby improving light emission efficiency, and can be silicon dioxide; the DBR reflective layer 170, namely the distributed Bragg mirror, provides high reflectivity and chemical stability, and is composed of alternating high and low refractive index media to enhance light extraction, and can be formed by alternating titanium dioxide and silicon dioxide.

[0040] As one possible implementation, the metal reflective layer 180 includes a silver layer, a titanium layer, and a nickel layer disposed sequentially.

[0041] The silver layer has high reflectivity, ensuring maximum light extraction efficiency. The titanium layer acts as an adhesion medium, effectively mitigating the weak bonding between Ag and oxide interfaces. The nickel layer is chemically stable, dense, and corrosion-resistant, effectively blocking silver ion diffusion and environmental erosion, thereby inhibiting silver migration and corrosion. Furthermore, the Ti / Ni bilayer buffers the difference in thermal expansion coefficients between Ag and the underlying material, reducing delamination or cracking caused by thermal cycling. Therefore, the metal reflective layer 180, comprising the sequentially arranged silver, titanium, and nickel layers, can improve the stability of the reflective layer while ensuring high reflectivity.

[0042] Optional, such as Figure 3 As shown, an N-type ohmic contact block 510 is also provided between the N-type metal 210 and the N-type layer 120, and the N-type metal 210 encloses the N-type ohmic contact block 510.

[0043] As can be seen from the hierarchical relationship, the N-type metal 210 needs to extend into the structure to a relatively deep depth. In the subsequent fabrication process, it is fabricated simultaneously with the P-type metal 220. In this way, it is easy for the N-type metal 210 to fail to make good contact with the N-type layer 120. In this embodiment of the application, an N-type ohmic contact block 510 is also provided between the N-type metal 210 and the N-type layer 120, thereby improving the contact of the N-type electrical connection, reducing the N-type resistance, and improving the injection efficiency and the optoelectronic performance of the device.

[0044] Among them, the N-type ohmic contact block 510 is made of highly doped N-type material (such as n + It is constructed from GaN or a dedicated ohmic contact metal (such as Ti / Al) to form a low-resistance, stable ohmic contact interface.

[0045] As an feasible approach, such as Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the connection hole includes multiple P-type holes 620 and multiple N-type holes 610. The current spreading layer 150 is exposed through the P-type holes 620, and the N-type layer 120 is exposed through the N-type holes 610. The multiple N-type holes 610 are arranged in an array, and each N-type hole 610 is surrounded by at least 4 P-type holes 620.

[0046] Multiple P-type interconnects and multiple N-type vias are etched at the top of the hierarchical structure. The P-type vias 620 penetrate to the current spreading layer 150 and are exposed therethrough, while the N-type vias 610 penetrate to the N-type layer 120 and are exposed therethrough. Specifically, the multiple N-type vias 610 are arranged in an array, and each N-type via 610 is surrounded by at least four P-type vias 620, forming a local PNPN staggered layout. Each via is filled with metal, forming a P-type metal 220 and an N-type metal 210.

[0047] During operation, current is injected from an external power source into the P-type layer 140 via the P-type metal 220, and simultaneously injected into the N-type layer 120 via the N-type metal 210. Charge carriers recombine and emit light in the multiple quantum wells. Since each N-type hole 610 is surrounded by multiple P-type holes 620, the current path is more uniformly distributed laterally, avoiding the current congestion effect caused by a traditional single large-area electrode. At the same time, the high-density staggered arrangement of P / N electrodes shortens the lateral transport distance of charge carriers, reduces the burden on the current extension layer 150, and improves the uniformity of light emission and internal quantum efficiency.

[0048] The specific arrangement of the P-type hole 620 and the N-type hole 610 is not limited in the embodiments of this application. For example, it can be as follows: Figure 5 As shown, six P-type holes 620 are evenly distributed around the outer periphery of each N-type hole 610; alternatively, as shown... Figure 6 As shown, each N-type hole 610 has 6 P-type holes 620 arranged around its outer periphery; alternatively, as shown... Figure 7 As shown, each N-type hole 610 has 10 P-type holes 620 arranged around its outer periphery; alternatively, as shown... Figure 8 As shown, eight P-type holes 620 are arranged around the periphery of each N-type hole 610. It can be understood that the aforementioned P-type holes 620 can simultaneously surround the periphery of each N-type hole 610 in an adjacent chain.

[0049] As one possible implementation method, such as Figure 9As shown, the N-type hole 610 is formed by connecting a first through hole on the metal reflective layer 180, a second through hole on the DBR reflective layer 170, and a third through hole on the current blocking layer 160; the diameter of the first through hole is larger than the diameters of the second and third through holes.

[0050] The N-type aperture 610 is formed by longitudinally aligning and connecting through holes on three different functional film layers. Specifically, from top to bottom, it includes a first through hole on the metal reflective layer 180, a second through hole on the DBR reflective layer 170, and a third through hole on the current blocking layer 160, all of which extend to the N-type layer below. In particular, the diameter of the first through hole is larger than the diameters of the second and third through holes, forming a larger aperture structure at the bottom.

[0051] The large holes at the bottom ensure low-resistance ohmic contact, while the small holes at the top reduce damage to the high-reflectivity metal layer (such as Ag) and maintain high light extraction efficiency. In addition, the larger hole structure at the bottom promotes good metal wetting and anchoring, preventing electrode peeling under thermal cycling or mechanical stress.

[0052] Optionally, the insulating layer 190 includes aluminum oxide and silicon dioxide stacked sequentially.

[0053] The insulating layer 190 is a composite passivation structure composed of sequentially stacked aluminum oxide (Al2O3) and silicon dioxide (SiO2), covering the metal reflective layer 180 and the entire chip surface. Connecting holes are etched at specific locations to expose the N-type layer 120 and the P-type layer 140. Typically, aluminum oxide serves as the bottom layer, directly contacting the metal or semiconductor, while silicon dioxide acts as the top layer covering it. This double-layer insulation design combines the complementary advantages of the two materials: aluminum oxide possesses a high dielectric constant, excellent density, and strong barrier properties against moisture / ions, improving the reliability of the light-emitting diode 100; while silicon dioxide exhibits good flatness and low stress, preventing cracking.

[0054] As one feasible approach, the diameter of the connecting hole is between 10μm and 50μm, and the distance between two adjacent connecting holes is between 50μm and 300μm.

[0055] This size range balances electrical performance, optical integrity, and manufacturing feasibility. Specifically, the aperture setting ensures low contact resistance and reliable metal filling while avoiding excessive damage to the upper reflective structure; the aperture spacing prevents short circuits and crosstalk between electrodes while leaving reasonable space for photolithography alignment, metal deposition, and subsequent packaging processes.

[0056] Optionally, the N-polar metal 210 and the P-polar metal 220 have the same structure, which is a Cr / Ag / Ti / Al / Ti structure.

[0057] Specifically, Cr (chromium) serves as the bottom adhesion layer, enhancing the bonding force between the metal and the semiconductor or insulating layer 190; Ag (silver) provides high conductivity, reducing electrode resistance, and also reflects light; Ti (titanium) serves as a diffusion barrier layer, preventing Ag from dissolving or migrating with Al; Al (aluminum) serves as the main conductive layer, offering low cost and good conductivity, making it suitable for wire bonding or bump connections; the top Ti layer protects Al from oxidation and improves the interface stability with the packaging material.

[0058] After a silver layer is placed inside the N-polar metal 210 and P-polar metal 220, their reflectivity can reach 85%.

[0059] When P-metal 220 and N-metal 210 are used as Ppad710 and Npad720, gold needs to be added. If... Figure 2 When the Ppad710 and Npad720 are also included separately, gold is not required.

[0060] This application embodiment also provides a method for fabricating a light-emitting diode 100, used to fabricate the aforementioned light-emitting diode 100, such as... Figure 10 As shown, it includes: S100: As Figure 11 As shown, an N-type layer 120, a multiple quantum well layer 130, a P-type layer 140, and a current spreading layer 150 are sequentially disposed on the upper surface of the substrate 110. An N-type layer 120, a multi-quantum-well active layer, and a P-type layer 140 are sequentially epitaxially grown on the substrate 110, and a current spreading layer 150 is deposited to form the basic light-emitting structure. Specific materials have been described in the embodiment of the light-emitting diode 100 and will not be repeated here. The formation method is not limited in this application embodiment; examples include chemical vapor deposition, physical vapor deposition, etc.

[0061] S200: such as Figure 12 As shown, the current spreading layer 150, the P-type layer 140, and the multiple quantum well layer 130 are etched on the upper surface of the current spreading layer 150 to expose the N-type layer 120 and form an N-type sub-hole 611. Dry etching can be used to penetrate downwards from the surface of the current extension layer 150 through the P-type layer 140 and the MQW layer until the N-type layer 120 is exposed, forming an N-type sub-via to prepare for the subsequent N-electrode lead-out.

[0062] In practical applications, during the fabrication of LEDs 100, multiple LEDs 100 are typically formed on a single wafer. This allows for the formation of isolation trenches between adjacent LEDs 100 after the formation of the N-type aperture 610. Figure 13 As shown.

[0063] S300: such as Figure 14 , Figure 15 , Figure 16 and Figure 17 As shown, a composite structure is formed in the current spreading layer 150. The composite structure includes a current blocking layer 160 and / or a DBR reflective layer 170, a metal reflective layer 180 and an insulating layer 190 arranged sequentially. Multiple through holes and multiple P-type holes are formed on the composite structure. Multiple N-type sub-holes are connected to the multiple through holes one by one to form N-type holes. The N-type layer is exposed through the N-type holes, and the current spreading layer is exposed through the P-type holes. Specifically, forming a composite structure on the current spreading layer includes: S311: As Figure 14 As shown, a composite layer is disposed on the current spreading layer, the composite layer including a current blocking layer and / or a DBR reflective layer; A current blocking layer 160 and a DBR reflective layer 170 are sequentially deposited on the current spreading layer 150.

[0064] S312: As Figure 14 As shown, a metal reflective layer is formed on the composite layer and multiple first sub-holes are etched, wherein some of the first sub-holes are connected to N-type sub-holes; A metal reflective layer 180 is deposited on the DBR reflective layer 170, and then multiple first sub-holes are formed by selective etching. Some of the first sub-holes are connected to the N-type sub-holes one by one, and the other first sub-holes surround the outer periphery of the N-type sub-holes.

[0065] S313: As Figure 18 and Figure 19 As shown, an insulating layer is set on the metal reflective layer and etched to form multiple second sub-holes. The second sub-holes are connected to the first sub-holes one by one to form through holes. Some of the through holes are connected to the N-type sub-holes to form N-type holes, and the remaining through holes are P-type holes. The N-type holes through which the N-type layer passes are exposed, and the current spreading layer is exposed through the P-type holes. The insulating layer covers the sidewalls of the through holes.

[0066] When the insulating layer is set, the insulating layer extends to the sidewall of the first sub-hole, and when the insulating layer is etched, the metal reflective layer is wrapped by the insulating layer.

[0067] In practical applications, forming a composite structure on the current spreading layer can also include: S321: A composite layer, a metal reflective layer and an insulating layer are sequentially disposed on the current spreading layer. The composite layer includes a current blocking layer and / or a DBR reflective layer. S322: Etching forms multiple through holes, some of which are connected to the N-type sub-holes to form N-type holes, and the remaining through holes are P-type holes.

[0068] S323: An insulating sidewall connected to the insulating layer is formed on the sidewall of the through hole.

[0069] The two methods for forming composite structures described above can also be adjusted by those skilled in the art according to the actual situation, as long as N-type holes and P-type holes can be formed.

[0070] When the light-emitting diode 100 also includes an N-type ohmic contact, it can be as follows: Figure 20 As shown.

[0071] S400: such as Figure 21 and Figure 22 As shown, metal is filled into the P-type hole 620 and the N-type hole 610 to form N-polar metal 210 and P-polar metal 220.

[0072] Metal is filled into the P-type hole 620 and the N-type hole 610 to form the N-type metal 210 and the P-type metal 220, thus completing the electrode integration.

[0073] In practical applications, such as Figure 23 and Figure 24 As shown, an isolation layer 730 can also be provided on the P-metal 220, N-metal 210, and insulating layer 190. A Ppad 710 and an Npad 720, respectively connected to the P-metal 220 and N-metal 210, are provided on the isolation layer 730, as shown. Figure 2 As shown. The isolation layer 730 can be formed by stacking two materials, alumina and silicon oxide. Specifically, the thickness of the alumina is 1250 angstroms, the thickness of the silicon oxide is 4000 angstroms, and the thickness of the isolation layer 730 is 6250 angstroms.

[0074] The fabrication method of the light-emitting diode 100 is the same as that of the light-emitting diode 100, and will not be described in detail here.

[0075] As one possible implementation, a metal reflective layer 180 is formed on the composite layer and a plurality of first sub-holes are etched thereon, including: S420: The current blocking layer 160 and the DBR reflective layer 170 are used as a composite layer. The composite layer is etched to form multiple filling holes on the composite layer. S421: As Figure 16 and Figure 17 As shown, a metal reflective layer 180 is formed on the composite layer. The metal reflective layer 180 extends to the filling hole and connects with the current spreading layer 150, or the metal reflective layer 180 fills the filling hole.

[0076] The metal reflective layer 180 extends to the filling hole and connects with the current spreading layer 150. Alternatively, the beneficial effects of the metal reflective layer 180 filling the filling hole have been described in detail in the foregoing embodiments and will not be repeated here.

[0077] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0078] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

Claims

1. A light-emitting diode, characterized in that, The device comprises, in sequence, an N-type layer, a multiple quantum well layer, a P-type layer, a current spreading layer, a composite layer, a metal reflective layer, and an insulating layer. A connection hole is formed by etching downwards from the upper surface of the insulating layer, exposing the N-type layer and the current spreading layer respectively. The insulating layer covers the sidewalls of the connection hole. The connection hole is filled with metal as the N-polar metal and the P-polar metal. The N-polar metal is connected to the N-type layer, and the P-polar metal is connected to the P-type layer through the current spreading layer.

2. The light-emitting diode according to claim 1, characterized in that, Multiple filling holes are formed on the composite layer, and the metal reflective layer is disposed on the upper surface of the composite layer, or the metal reflective layer extends to the filling holes and connects with the current spreading layer, or the metal reflective layer fills the filling holes.

3. The light-emitting diode according to claim 1, characterized in that, The composite layer includes a current blocking layer and a DBR reflective layer.

4. The light-emitting diode according to claim 1, characterized in that, The metal reflective layer comprises a silver layer, a titanium layer, and a nickel layer arranged sequentially.

5. The light-emitting diode according to claim 1, characterized in that, An N-type ohmic contact block is further disposed between the N-pole metal and the N-type layer, and the N-pole metal encapsulates the N-type ohmic contact block.

6. The light-emitting diode according to claim 3, characterized in that, The connection hole includes multiple P-type holes and multiple N-type holes. The current spreading layer is exposed through the P-type holes, and the N-type layer is exposed through the N-type holes. The multiple N-type holes are arranged in an array, and each N-type hole is surrounded by at least 4 P-type holes.

7. The light-emitting diode according to claim 6, characterized in that, The N-type aperture is formed by connecting a first through-hole on the metal reflective layer, a second through-hole on the DBR reflective layer, and a third through-hole on the current blocking layer; the diameter of the first through-hole is larger than the diameters of the second and third through-holes.

8. The light-emitting diode according to claim 1, characterized in that, The insulating layer comprises aluminum oxide and silicon dioxide stacked sequentially.

9. The light-emitting diode according to claim 1, characterized in that, The diameter of the connecting hole is between 10μm and 50μm, and the distance between two adjacent connecting holes is between 50μm and 300μm.

10. The light-emitting diode according to claim 1, characterized in that, The N-polar metal and the P-polar metal have the same structure, which is a Cr / Ag / Ti / Al / Ti structure.

11. A method for fabricating a light-emitting diode, characterized in that, The method for preparing the light-emitting diode according to any one of claims 1 to 10 includes: An N-type layer, a multiple quantum well layer, a P-type layer, and a current spreading layer are sequentially disposed on the upper surface of the substrate; The current spreading layer, the P-type layer, and the multiple quantum well layer are etched from the upper surface of the current spreading layer to expose the N-type layer and form multiple N-type sub-holes. A composite structure is formed on the current spreading layer. The composite structure includes a current blocking layer and / or a DBR reflective layer, a metal reflective layer, and an insulating layer arranged sequentially. A plurality of through holes and a plurality of P-type holes are formed on the composite structure. A plurality of N-type sub-holes are connected to the plurality of through holes in a one-to-one manner to form N-type holes. The N-type layer is exposed through the N-type holes, and the current spreading layer is exposed through the P-type holes. The insulating layer covers the sidewalls of the through holes and the P-type holes. Metal is filled into the P-type hole and the N-type hole to form N-polar metal and P-polar metal.

12. The method for fabricating a light-emitting diode according to claim 11, characterized in that, The formation of the composite structure on the current spreading layer includes: A composite layer is disposed on the current spreading layer, the composite layer including a current blocking layer and / or a DBR reflective layer; A metal reflective layer is formed on the composite layer and a plurality of first sub-holes are etched thereon, wherein some of the first sub-holes are connected to the N-type sub-holes; An insulating layer is formed on the metal reflective layer by etching, forming a plurality of second sub-holes. The second sub-holes are connected to the first sub-holes one by one to form through holes. Some of the through holes are connected to the N-type sub-holes to form N-type holes, and the remaining through holes are P-type holes. The N-type layer is exposed through the N-type holes, and the current spreading layer is exposed through the P-type holes. The insulating layer covers the sidewalls of the through holes.

13. The method for fabricating a light-emitting diode according to claim 11, characterized in that, The formation of the composite structure on the current spreading layer includes: A composite layer, a metal reflective layer, and an insulating layer are sequentially disposed on the current spreading layer. The composite layer includes a current blocking layer and / or a DBR reflective layer. Multiple through holes are formed by etching, wherein some of the through holes serve as through holes and communicate with the N-type sub-holes to form N-type holes, and the remaining through holes serve as P-type holes; An insulating sidewall is formed on the sidewall of the through hole, which is connected to the insulating layer.

14. The method for preparing a light-emitting diode according to claim 12, characterized in that, The process of forming a metal reflective layer on the composite layer and etching to form a plurality of first sub-holes includes: The current blocking layer and the DBR reflective layer are used as a composite layer. The composite layer is etched to form a plurality of filling holes on the composite layer. A metal reflective layer is formed on the composite layer, the metal reflective layer extending to the filling hole and connecting with the current spreading layer, or the metal reflective layer fills the filling hole.

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