Light emitting diode, light emitting device and manufacturing method

Abstract

The present application relates to the technical field of semiconductor manufacturing, and particularly relates to a light emitting diode, a light emitting device and a manufacturing method. The light emitting diode comprises an epitaxial structure with a first surface and a second surface, and the epitaxial structure comprises a first semiconductor layer; the first semiconductor layer comprises a first ohmic contact layer on the side of the first surface, which is made of Al x Ga y InP, 0<=x<=1 or 0<=y<=1; a first metal electrode is located on the first surface and comprises a main electrode and a plurality of extension electrodes; the extension electrodes are located on the first ohmic contact layer; the projected area of the extension electrodes on the first surface is less than or equal to the projected area of the first ohmic contact layer on the first surface as viewed from the top. The present application can effectively solve the problem of large light absorption of the traditional GaAs as the ohmic contact layer, avoid the problem of unstable forward voltage output caused by wafer deformation or alignment deviation during the process of the traditional gold half contact, and effectively improve the electrochemical corrosion resistance of the entire electrode structure.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a light-emitting diode, a light-emitting device, and a method for manufacturing it. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor light-emitting element, typically made of binary, ternary, or quaternary semiconductors such as GaN, GaAs, GaP, AlGaAs, and AlxGayInP. Its core is a PN structure with light-emitting properties; electrons are injected from the N-region into the P-region, and holes are injected from the P-region into the N-region. The recombination of electrons and holes causes the LED to emit light. LEDs have advantages such as high luminous intensity, high efficiency, small size, and long lifespan, and are widely used in various fields.

[0003] GaAs crystals are of high quality and can form excellent gold-half ohmic contacts with metals, making them a widely used ohmic contact layer material in LEDs. However, due to its intrinsic wavelength of 860nm, it absorbs light very strongly in the red, yellow, and green light bands. To reduce GaAs light absorption, during the manufacturing process, while ensuring voltage stability, the GaAs beneath the main electrode and, in large-size products, is typically hollowed out. The extended electrodes are usually fabricated using a process where a metal electrode is coated with the ohmic contact material, as shown in the diagram. Figure 1 As shown. Because the metal blocks light, the metal electrode must be made as small as possible within the process window. Therefore, traditional structures suffer from unstable forward voltage output due to wafer deformation or misalignment. Thus, optimizing the design of the ohmic contact material and its paired metal electrode to solve the problems of insufficient luminous efficiency and poor process performance of LEDs is one of the technical challenges that urgently needs to be addressed by those skilled in the art. Summary of the Invention

[0004] One embodiment of the present invention provides a light-emitting diode, the light-emitting diode including at least an epitaxial structure and a first metal electrode.

[0005] The epitaxial structure has opposing first and second surfaces, and includes a first type of semiconductor layer, a light-emitting layer, and a second type of semiconductor layer stacked sequentially; the first type of semiconductor layer includes a first ohmic contact layer located on the first surface side of the epitaxial structure; the material of the first ohmic contact layer is Al. x Ga yInP, where 0≤x≤1 or 0≤y≤1; the first metal electrode is located on the first surface of the epitaxial structure; the first metal electrode includes a main electrode and a plurality of extended electrodes; the extended electrodes are located on the first ohmic contact layer and are electrically connected to the first ohmic contact layer; from a top view, the projected area of ​​the extended electrodes on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer on the first surface.

[0006] In one embodiment, the extended electrode does not cover the side of the first ohmic contact layer.

[0007] In one embodiment, the main electrode is located on the first ohmic contact layer or on the first surface that is not covered by the first ohmic contact layer.

[0008] In one embodiment, the first metal electrode comprises at least three elements: gold, germanium, and nickel, and their alloys.

[0009] In one embodiment, the nickel content first increases and then decreases along the direction from the bottom surface of the first metal electrode close to the first surface to the top surface.

[0010] In one embodiment, the first metal electrode further includes titanium and platinum.

[0011] In one embodiment, the titanium element is located closer to the first ohmic contact layer on the first metal electrode than the platinum element, and the platinum element is adjacent to the titanium element.

[0012] In one embodiment, the titanium element has a thickness greater than 800 angstroms on the first metal electrode.

[0013] In one embodiment, the first ohmic contact layer contains nickel.

[0014] In one embodiment, the first type of semiconductor layer further includes at least one first window layer, the first window layer being located on the side of the first ohmic contact layer away from the first metal electrode; the material of the first window layer is Al. m Ga n InP, where 0≤m≤1 or 0≤n≤1; wherein the Al content in the first ohmic contact layer is less than the Al content in the first window layer.

[0015] In one embodiment, the thickness of the first ohmic contact layer is greater than 300 angstroms and less than the thickness of the first window layer.

[0016] In one embodiment, the thickness of the first window layer is less than 5 μm.

[0017] In one embodiment, the first ohmic contact layer is N-type doped, the first window layer is N-type doped, and the doping concentration of the first window layer is lower than that of the first ohmic contact layer.

[0018] In one embodiment, the doping concentration of the first ohmic contact layer is greater than 4E±18 / cm. 3 The doping concentration of the first window layer is 4E+17 to 4E+18 / cm³. 3 .

[0019] In one embodiment, the Al x Ga y InP and Al m Ga n In InP, mx≥0.2.

[0020] In one embodiment, the Al x Ga y InP and Al m Ga n In InP, x ranges from 0.2 to 1, and m ranges from 0 to 0.8.

[0021] In one embodiment, the first surface of the epitaxial structure is a roughened surface or an unroughened surface.

[0022] In one embodiment, in a first surface of the epitaxial structure that is a roughened surface, the first metal electrode is located on an unroughened surface.

[0023] In one embodiment, the wavelength range emitted by the light-emitting diode is 550nm to 750nm.

[0024] The present invention also provides a light-emitting diode, wherein the light-emitting diode includes at least an epitaxial structure and a first metal electrode.

[0025] The epitaxial structure has opposing first and second surfaces, and includes a first type of semiconductor layer, a light-emitting layer, and a second type of semiconductor layer stacked sequentially; the first type of semiconductor layer includes a first ohmic contact layer located on the first surface side of the epitaxial structure; the material of the first ohmic contact layer is Al. x Ga y InP, where 0≤x≤1 or 0≤y≤1; the first metal electrode is located on the first surface of the epitaxial structure; the first metal electrode includes a main electrode and a plurality of extended electrodes; the extended electrodes are located on the first ohmic contact layer and are electrically connected to the first ohmic contact layer; the first metal electrode is composed of at least three elements, gold, germanium, and nickel, and their alloys; the nickel content first increases and then decreases along the direction from the bottom surface of the first metal electrode close to the first surface to the upper surface.

[0026] In one embodiment, the first metal electrode further includes titanium and platinum.

[0027] In one embodiment, the titanium element is located closer to the first ohmic contact layer on the first metal electrode than the platinum element, and the platinum element is adjacent to the titanium element.

[0028] In one embodiment, the titanium element has a thickness greater than 800 angstroms on the first metal electrode.

[0029] In one embodiment, the first ohmic contact layer contains nickel.

[0030] In one embodiment, the first type of semiconductor layer further includes at least one first window layer, the first window layer being located on the side of the first ohmic contact layer away from the first metal electrode; the material of the first window layer is Al. m Ga n InP, where 0≤m≤1 or 0≤n≤1; wherein the Al content in the first ohmic contact layer is less than the Al content in the first window layer.

[0031] In one embodiment, the first ohmic contact layer is N-type doped, the first window layer is N-type doped, and the doping concentration of the first window layer is lower than that of the first ohmic contact layer.

[0032] In one embodiment, the doping concentration of the first ohmic contact layer is greater than 4E±18 / cm. 3 The doping concentration of the first window layer is 4E+17 to 4E+18 / cm³. 3 .

[0033] In one embodiment, the Al x Ga y InP and Al m Ga n In InP, mx≥0.2.

[0034] In one embodiment, the Al x Ga y InP and Al m Ga n In InP, x ranges from 0.2 to 1, and m ranges from 0 to 0.8.

[0035] The present invention also provides a light-emitting device, wherein the light-emitting device employs a light-emitting diode as described in any of the above embodiments.

[0036] This invention also provides a method for manufacturing a light-emitting diode, comprising the following steps:

[0037] An epitaxial structure is provided, the epitaxial structure having opposing first and second surfaces, and comprising a first type of semiconductor layer, a light-emitting layer, and a second type of semiconductor layer sequentially stacked from the first surface to the second surface; the first type of semiconductor layer includes a first ohmic contact layer; the material of the first ohmic contact layer is Al. x Ga y InP, where 0≤x≤1 or 0≤y≤1; a first metal electrode is fabricated on the first surface of the epitaxial structure, the first metal electrode including a main electrode and a plurality of extended electrodes; the extended electrodes are fabricated on a first ohmic contact layer, and from a top view, the projected area of ​​the extended electrodes on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer on the first surface.

[0038] An embodiment of the present invention provides a light-emitting diode by setting the material of the ohmic contact layer to Al. x Ga y InP material has a much lower light absorption effect than GaAs, thus effectively solving the problem of significant light absorption when using GaAs as an ohmic contact layer. By adjusting the material composition of the first metal electrode, a good ohmic contact is formed between the first metal electrode and the first ohmic contact layer, thereby obtaining a stable operating voltage. The projected area of ​​the ohmic contact layer is set to be greater than or equal to the projected area of ​​the corresponding metal electrode, thus avoiding the problem of unstable forward voltage output caused by wafer deformation or misalignment during processing when the projected area of ​​the ohmic contact layer is smaller than that of the metal electrode.

[0039] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of metal electrodes coated with ohmic contact materials in the prior art;

[0042] Figure 2 This is a schematic diagram of the structure of a light-emitting diode in one embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of a diode structure in which the first ohmic contact layer covers the entire first surface;

[0044] Figure 4 This is a schematic diagram of a diode structure in which the main electrode is disposed on the first surface that is not covered by the first ohmic contact layer.

[0045] Figure 5 This is a schematic diagram of a diode structure where the projected area of ​​the extended electrode is smaller than the projected area of ​​the first ohmic contact layer.

[0046] Figure 6 This is a schematic diagram of a diode structure in which the main electrode is disposed on the first ohmic contact layer.

[0047] Figure 7 This is a schematic diagram of the structure of the flip-chip light-emitting diode provided by the present invention;

[0048] Figures 8-10 These are schematic diagrams illustrating the structure of a light-emitting diode at different manufacturing stages, as shown in embodiments of the present invention.

[0049] Figure label:

[0050] 20 - Epitaxial structure; 21 - First type semiconductor layer; 22 - Light-emitting layer; 23 - Second type semiconductor layer; 21a - First ohmic contact layer; 21b - First window layer; 30 - First metal electrode; 31 - Main electrode; 32 - Extended electrode; 40 - Mirror layer; 50 - Current blocking layer; 60 - Substrate; 70 - Bonding layer; 80 - Second metal electrode; 90 - Temporary substrate; X - Projected size of extended electrode; Y - Projected size of first ohmic contact layer. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings; the technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] Please see Figure 2 , Figure 2 This is a schematic diagram of a light-emitting diode (LED) structure in one embodiment of the present invention. To achieve at least one or more of the aforementioned advantages, one embodiment of the present invention provides an LED that may include at least an epitaxial structure 20 and a first metal electrode 30.

[0053] The epitaxial structure 20 is grown on a temporary substrate 90 using methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), epitaxy growth technology, and atomic beam deposition (ALD). The epitaxial structure 20 has opposing first and second surfaces, and sequentially includes a first type semiconductor layer 21, a light-emitting layer 22, and a second type semiconductor layer 23 along the direction from the first surface to the second surface.

[0054] In this embodiment, the first type semiconductor layer 21 and the second type semiconductor layer 23 are semiconductors with different conductivity types, electrical properties, and polarities, depending on the doped elements that provide electrons or holes. For example, when the first type semiconductor layer 21 is n-type, the second type semiconductor layer is p-type. The light-emitting layer 22 is formed between the first and second semiconductor layers. Electrons and holes recombine within the light-emitting layer 22 under the drive of a current, converting electrical energy into light energy to emit light. The wavelength of the light emitted by the light-emitting diode can be adjusted by changing the physical and chemical composition of one or more layers of the epitaxial light-emitting layer 22; conversely, the wavelength can be adjusted by changing the composition of the epitaxial light-emitting layer 22. In this embodiment, a light-emitting diode with the first type semiconductor layer 21 being n-type and the second type semiconductor layer 23 being p-type is preferred.

[0055] The light-emitting layer 22 provides light radiation for electron-hole recombination. Different materials can be selected depending on the emission wavelength. The material of the light-emitting layer 22 is aluminum gallium indium phosphide (AlGaInP) series, emitting red light. It can be a single heterostructure (SH), double heterostructure (DH), double-sided double heterostructure (DDH), or multi-quantum well (MQW). The light-emitting layer 22 includes a well layer and a barrier layer, where the barrier layer has a larger band gap than the well layer. By adjusting the composition ratio of the semiconductor material in the light-emitting layer 22, different wavelengths of light can be emitted. In this embodiment, the light-emitting layer 22 preferably radiates light in the 550–750 nm wavelength range, such as red, yellow, or orange light. The light-emitting layer 22 is a material layer that provides electroluminescent radiation, such as aluminum gallium indium phosphide (AlGaInP) or aluminum gallium arsenide (AlGaInP), more preferably AlGaInP, which can be a single quantum well or a multi-quantum well. In this embodiment, the epitaxial structure 20 preferably radiates red light.

[0056] Please refer to the following: Figure 2 The first type of semiconductor layer 21 includes a first ohmic contact layer 21a, which is located on the first surface side of the epitaxial structure 20; the material of the first ohmic contact layer 21a is Al. x Ga y InP, where 0≤x≤1 or 0≤y≤1.

[0057] Specifically, the first ohmic contact layer 21a uses short-wavelength materials such as aluminum gallium indium phosphide (AGaInP) (intrinsic wavelength between 490 and 650 nm), aluminum indium phosphide (AIP) (intrinsic wavelength of 490 nm), or gallium indium phosphide (AIP) (intrinsic wavelength of 650 nm), whose light absorption is much lower than that of GaAs (intrinsic wavelength of 860 nm). When applied to light-emitting diodes (LEDs) such as those producing red or near-infrared light, the significantly reduced light absorption of the ohmic contact layer effectively improves the LED's brightness. Especially when used in LED plant lights, aluminum gallium indium phosphide or aluminum indium phosphide is preferred as the ohmic contact layer. Furthermore, for different purposes, such as matching the lattice constant of the temporary substrate 90 or adjusting the dominant wavelength, the element content can be adjusted as needed, and no limitation is made here.

[0058] In this implementation, such as Figure 2 As shown, the first metal electrode 30 is located on the first surface of the epitaxial structure 20; the first metal electrode 30 includes a main electrode 31 and a plurality of extended electrodes 32; the extended electrodes 32 are located on the first ohmic contact layer 21a and are electrically connected to the first ohmic contact layer 21a. Preferably, please refer to... Figure 4 and Figure 6 The main electrode 31 is located on the first ohmic contact layer 21a or on the first surface that is not covered by the first ohmic contact layer 21a.

[0059] The main electrode 31 can be disposed on the first surface of the first ohmic contact layer 21a to achieve ohmic contact between the main electrode 31 and the first ohmic contact layer 21a. Since the first ohmic contact layer 21a has a high n-type doping concentration, it will exhibit a certain light absorption effect. Therefore, in some optional embodiments, the ohmic contact layer below the main electrode 31 can be removed by etching to reduce light absorption below the main electrode 31 and further improve brightness.

[0060] Furthermore, viewed from above, the projected area of ​​the extended electrode 32 on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer 21a on the first surface. In a specific implementation, the projected area of ​​the extended electrode 32 on the first surface is equal to the projected area of ​​the first ohmic contact layer 21a on the first surface, such as... Figure 2 , Figure 4 As shown, in the cross-sectional view, the projected dimension X of the extended electrode 32 can be represented as equal to the projected dimension Y of the first ohmic contact layer 21a; as Figure 3As shown, the first ohmic contact layer 21a can cover the entire surface of the first surface, that is, in the cross-sectional view, the projected size Y of the first ohmic contact layer 21a is much larger than the projected size X of the extended electrode 32; the projected area of ​​the first ohmic contact layer 21a on the first surface is larger than the projected area of ​​the extended electrode 32 on the first surface, and it does not cover the entire surface of the first surface, such as... Figure 5 As shown in the cross-sectional view, the projected size Y of the first ohmic contact layer 21a is slightly larger than the projected size X of the extended electrode 32. That is, through... Figures 2-5 As can be seen from the embodiments, since the first ohmic contact layer 21a uses Al x Ga y The InP material reduces light absorption in the first ohmic contact layer 21a, thus allowing for an increase in its area. This area can be greater than or equal to the area of ​​the extended electrode 32, thereby increasing current spreading. Simultaneously, the projected area of ​​the first ohmic contact layer 21a can be made smaller than the projected area of ​​the extended electrode 32. Figure 1 As shown in the cross-sectional view, the projected size Y of the first ohmic contact layer 21a is smaller than the projected size X of the extended electrode 32. This can be flexibly adjusted according to the specific design. However, since the light absorption of the first ohmic contact layer 21a is reduced, there is no longer any concern about the light absorption problem caused by the excessive area of ​​the first ohmic contact layer 21a. Therefore, it becomes possible to increase the area of ​​the first ohmic contact layer 21a.

[0061] By setting the projection relationship between the extended electrode 32 and the first ohmic contact layer 21a as described above, on the one hand, when the light-shielding area of ​​the first metal electrode 30 is the same, the projection of the first ohmic contact layer 21a is the same as the projection of the first metal electrode 30, which enables effective utilization of the metal area. On the other hand, its process is simpler, which not only reduces the corresponding processing cost, but also avoids the problem of unstable forward voltage output caused by wafer deformation or misalignment in the traditional metal electrode coating ohmic contact layer process.

[0062] When the first surface is a light-emitting surface, to increase the light extraction efficiency, the first surface of the epitaxial structure 20 can be a roughened surface or a non-roughened surface. For example... Figure 2 , Figure 3 The image shows the first surface as an unroughened surface, as shown. Figure 4 , Figure 5 , Figure 6 The diagram shows a roughened surface as the first surface. This roughened surface can be randomly roughened or have a regularly patterned surface texture. In the case of a roughened surface on the first surface of the epitaxial structure 20, the first metal electrode 30 is located on an unroughened surface.

[0063] Traditional metal electrode materials primarily consist of gold and small amounts of germanium and nickel, enabling them to form good ohmic contacts with GaAs materials. However, in this invention, the first ohmic contact layer 21a is replaced by Al instead of the traditional GaAs material. x Ga y Short-wavelength InP materials, through experiments, have shown that traditional metal electrode materials are comparable to Al. x Ga y InP materials are relatively poor at forming ohmic contacts. Therefore, in this embodiment, the first metal electrode 30 comprises at least three elements: gold, germanium, and nickel, and their alloys. Specifically, the nickel content first increases and then decreases along the direction from the bottom surface of the first metal electrode 30 near the first surface to the top surface. Taking an EDS test of the first metal electrode 30 as an example, the nickel content is located on the bottom surface of the first metal electrode 30 near the first surface, and appears as a waveform line that first increases and then decreases in the image. By increasing the nickel content, the first metal electrode 30 and the Al... x Ga y Ohmic contacts are more easily formed between the epitaxial structures 20 of the InP ohmic contact material. Preferably, the first ohmic contact layer 21a contains nickel, which diffuses into the first ohmic contact layer 21a during the fusion of the first metal electrode 30 to adjust the barrier height and improve the overall ohmic contact characteristics of the material.

[0064] This embodiment is applied in the manufacturing process of a vertically oriented diode. Since the reflection system and bonding structure are completed before the metal electrode is fused, high-temperature fusion of the metal electrode would damage the reflection system and bonding structure. Therefore, in a vertically oriented diode, the first metal electrode 30 needs to be manufactured by low-temperature fusion to avoid damage to the reflection system and bonding structure by high-temperature fusion.

[0065] During the low-temperature fusion process, the first metal electrode 30 also includes titanium and platinum. The addition of platinum can lower the fusion temperature of the first metal electrode 30, which is beneficial for low-temperature fusion of the light-emitting diode with the completed reflection system and bonding structure, and low-temperature fusion makes it easier to form ohmic contacts.

[0066] Preferably, titanium is positioned closer to the first ohmic contact layer 21a on the first metal electrode 30 than platinum, with platinum adjacent to titanium. Titanium effectively blocks the diffusion of germanium and nickel to the upper surface of the first metal electrode 30, thereby concentrating germanium and nickel at the bottom of the first metal electrode 30 and forming a good ohmic contact with the epitaxial structure 20 containing aluminum, indium, phosphorus, and gallium. To ensure the blocking effect of titanium, more preferably, the thickness of titanium on the first metal electrode 30 is greater than 800 angstroms and less than 2000 angstroms.

[0067] By adjusting the composition of each element in the first metal electrode 30 as described above, it can be ensured that the connection stability between the first ohmic contact layer 21a and the first metal electrode 30 is good and the ohmic contact effect is good when using short-wavelength materials such as aluminum gallium indium phosphide, aluminum indium phosphide, or gallium indium phosphide, thereby obtaining a stable working voltage.

[0068] Preferably, such as Figure 2 As shown, the first type of semiconductor layer 21 further includes at least one first window layer 21b, which is located on the side away from the first ohmic contact layer 21a of the first metal electrode 30; the material of the first window layer 21b is Al. m Ga n InP, where 0≤m≤1 or 0≤n≤1; wherein, the Al content in the first ohmic contact layer 21a is less than the Al content in the first window layer 21b. Of course, the Al content in the first ohmic contact layer 21a can be equal to the Al content in the first window layer 21b, and can be flexibly adjusted according to actual needs, without limitation here. Furthermore, the material ratio of the first ohmic contact layer 21a can be exactly the same as the material ratio of the first window layer 21b, both being Al... x Ga y InP material can also be flexibly adjusted according to actual needs.

[0069] With the above configuration, on the one hand, the first ohmic contact layer 21a, made of aluminum gallium indium phosphide (AGaInP) or aluminum indium phosphide (AIP), can form a homologous material with the first window layer 21b, resulting in a smaller potential barrier height between them. This reduces the intrinsic wavelength of the first ohmic contact layer 21a and the first window layer 21b within the light-emitting diode, reduces light absorption by the light-emitting diode, and enhances the external quantum effect. On the other hand, the Al content in the first ohmic contact layer 21a is lower than the Al content in the first window layer 21b. This configuration can reduce the potential difference, resulting in lower impedance of the gold-semiconductor contact and better ohmic contact performance.

[0070] Furthermore, the thickness of the first ohmic contact layer 21a is greater than 300 angstroms and less than the thickness of the first window layer 21b. Preferably, the thickness of the first window layer 21b is less than 5 μm.

[0071] In some embodiments, preferably, the first ohmic contact layer 21a is N-type doped, the first window layer 21b is N-type doped, and the doping concentration of the first window layer 21b is lower than that of the first ohmic contact layer 21a. A higher ohmic contact layer concentration results in a lower voltage; a lower window layer doping concentration results in less light absorption and higher brightness. Therefore, high doping of the first ohmic contact layer 21a makes ohmic contact easier to achieve, while low doping of the first window layer 21b results in higher brightness for the light-emitting diode. More preferably, the doping concentration of the first ohmic contact layer 21a is greater than 4E±18 / cm². 3 The doping concentration of the first window layer 21b is 4E+17 to 4E+18 / cm². 3 .

[0072] In some preferred embodiments, in Al x Ga y InP and Al m Ga n In InP, mx ≥ 0.2. More preferably, in Al... x Ga y InP and Al m Ga n In InP, x ranges from 0.2 to 1, and m ranges from 0 to 0.8.

[0073] Based on the light-emitting diodes provided in the above embodiments, please continue to refer to... Figures 2-6 The light-emitting diode also includes a reflector layer 40, a current blocking layer 50, a substrate 60, and a second metal electrode 80.

[0074] The mirror layer 40 is located on the second surface of the epitaxial structure 20. Preferably, the mirror layer 40 can be a distributed Bragg reflector (DBR) comprising alternating stacked first and second layers, wherein the refractive index of the first layer is different from that of the second layer. The materials of the first and second layers include TiO₂. X SiO X or AlO X The reflector layer 40 can also be a full-angle reflector (ODR); it comprises selecting metal materials such as Al, Ag, and Au and combining them with the DBR or dielectric oxide layer to form a full-angle reflector. Of course, current spreading layers, transparent conductive layers, and other structures can also be added to the reflector layer 40 to improve the overall performance of the light-emitting diode.

[0075] A current blocking layer 50 is disposed between the mirror layer 40 and the epitaxial structure 20. The current blocking layer 50 has multiple through openings through which the mirror layer 40 contacts the second type semiconductor layer 23. Specifically, the current blocking layer 50 may be composed of at least one of fluorides, nitrides, or oxides, such as ZnO or SiO2. X SiN X SiO X N Y Al2O3, TiO X It is formed of at least one material selected from MgF or GaF. The current blocking layer 50 can be composed of at least one or more dielectric layer materials with different refractive indices, and more preferably, the current blocking layer 50 is a transparent dielectric layer, allowing at least 50% of the light to pass through it. More preferably, the refractive index of the current blocking layer 50 is lower than that of the epitaxial structure 20. The current blocking layer 50 can form a total internal reflection system with the mirror layer 40, returning the light radiated from the epitaxial structure 20 towards the substrate 60 back to the epitaxial structure 20 and radiating it out from the first surface, thereby improving the light extraction efficiency.

[0076] The substrate 60 is located on the side of the reflector layer 40 away from the epitaxial structure 20; the substrate 60 can be a conductive substrate or a non-conductive substrate, and can also be transparent or opaque. Preferably, GaP, SiC, Si, or GaAs, which have conductive properties, can be selected as the conductive substrate.

[0077] Furthermore, a bonding layer 70 is formed between the substrate 60 and the mirror layer 40. The bonding layer 70 includes a transparent conductive oxide, a metallic material, an insulating oxide, or a polymer. The transparent conductive oxide includes indium tin oxide (ITO), indium oxide (INO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), zinc aluminum oxide (AZO), zinc tin oxide (ZTO), gallium-doped zinc oxide (GZO), tungsten-doped indium oxide (IWO), zinc oxide (ZnO), or indium zinc oxide (IZO). The metallic material includes In, Sn, Au, Ti, Ni, Pt, W, or alloys thereof. The insulating oxide includes aluminum oxide (AlO). X ), silicon dioxide (SiO) X ) or silicon oxynitride (SiO) X N Y The polymer includes epoxy resins, polyimides, perfluorocyclobutane, benzocyclobutene (BCB), or siloxanes.

[0078] The second metal electrode 80 is located on the substrate 60 and is used to conduct current between the second metal electrode 30 and the substrate 60. The material of the second metal electrode 80 includes a transparent conductive material or a metallic material, wherein the transparent conductive material includes a transparent conductive oxide, and the metallic material includes Au, Pt, GeAlNi, Ti, BeAu, GeAu, Al, or ZnAu.

[0079] In addition to the light-emitting diode structural features described above in this embodiment, those skilled in the art can add other light-emitting diode structural features based on this embodiment to achieve the corresponding purpose.

[0080] This embodiment also provides a light-emitting device, which adopts a light-emitting diode structure as described in any of the above embodiments or preferred embodiments and combinations thereof, and uses the red light or infrared light radiation provided by the light-emitting diode for corresponding display, lighting or other optical device use.

[0081] Figures 8-10 This is a schematic diagram illustrating the structure of a light-emitting diode at different manufacturing stages, as shown in embodiments of the present invention. The present invention also provides a method for manufacturing a light-emitting diode, the method comprising at least the following steps:

[0082] Please refer to Figure 8 An epitaxial structure 20 is fabricated on a temporary substrate 90. The epitaxial structure 20 has opposing first and second surfaces and includes a first semiconductor layer 21, a light-emitting layer 22, and a second semiconductor layer 23 sequentially stacked on the temporary substrate 90 from the first surface to the second surface. The epitaxial structure 20 can be grown on the temporary substrate 90 using known methods, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), epitaxial growth (EGT), and atomic beam deposition (ALD).

[0083] The first type of semiconductor 21 includes a first ohmic contact layer 21a and a first window layer 21b; the material of the first ohmic contact layer 21a is Al. x Ga y InP, where 0≤x≤1 or 0≤y≤1.

[0084] Furthermore, the fabrication of a vertically oriented diode also includes the following steps: Please refer to... Figure 9A current blocking layer 50 is prepared on the side of the second type semiconductor layer 23 away from the light-emitting layer 22. In this embodiment, the current blocking layer 50 is preferably SiO2. An opening is formed in the current blocking layer 50 using a masking and etching process. Then, a reflective mirror layer 40 is prepared on the side of the current blocking layer 50 away from the second type semiconductor layer 23. A bonding layer 70 is formed on the side of the reflective mirror layer 40 and bonded to the substrate 60 using a bonding process. Next, a wet etching process is used to remove the temporary substrate 90 and expose the first ohmic contact layer 21a to obtain the desired result. Figure 10 The structure of the light-emitting diode shown is shown.

[0085] Next, a first metal electrode 30 is fabricated on the first surface of the epitaxial structure 20. The first metal electrode 30 includes a main electrode 31 and a plurality of extended electrodes 32. The main electrode 31 is deposited on the first ohmic contact layer 21a or on the first surface not covering the first ohmic contact layer 21a. The extended electrodes 32 are deposited on the first ohmic contact layer 21a, and from a top view, the projected area of ​​the extended electrodes 32 on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer 21a on the first surface.

[0086] Simultaneously, a second metal electrode 80 is fabricated on the side of the substrate 60 away from the mirror layer 40 to obtain, as shown in the figure. Figure 2 , Figure 3 The structure of the light-emitting diode shown is shown.

[0087] Alternatively, the first surface can be roughened using a masking and etching process. In this embodiment, a wet etching method is preferred, using a mixture of one or more of sulfuric acid, phosphoric acid, nitric acid, acetic acid, oxalic acid, and hydrofluoric acid for roughening, thereby obtaining the desired result. Figure 4 , Figure 5 , Figure 6 The structure of the light-emitting diode shown is shown.

[0088] In a preferred embodiment, the fabrication of the first metal electrode includes the steps of: forming a first metal electrode 30 by high-temperature fusion of at least three elements, namely gold, germanium, and nickel, and their alloys; or forming a first metal electrode 30 by low-temperature fusion of at least five elements, namely gold, germanium, nickel, titanium, and platinum, and their alloys.

[0089] Specifically, for light-emitting diodes where the reflection system and bonding structure are not completed before the metal electrodes are fused, for example... Figure 7 The horizontally structured light-emitting diode shown can be formed by high-temperature fusion of a material containing at least three elements—gold, germanium, and nickel—and their alloys to form the first metal electrode 30. Optionally, the high-temperature fusion temperature range is between 380°C and 520°C. For light-emitting diodes where the reflective system and bonding structure are completed before the metal electrode fusion, for example... Figures 2-6The vertically structured light-emitting diode shown can be formed by low-temperature fusion of a material containing at least five elements—gold, germanium, nickel, titanium, and platinum—and their alloys to form the first metal electrode 30. Optionally, the low-temperature fusion temperature range is between 280°C and 380°C.

[0090] In summary, compared with the prior art, the light-emitting diode provided by the present invention sets the material of the ohmic contact layer to Al. x Ga y The InP material has a much lower light absorption effect than GaAs, thus effectively solving the problem of poor light extraction efficiency in LEDs caused by the strong light absorption of traditional GaAs as an ohmic contact layer, significantly improving the brightness of the LED. Specifically, the projected area of ​​the first metal electrode on the epitaxial structure is less than or equal to the projected area of ​​the first ohmic contact layer on the epitaxial structure. This design avoids the problem of unstable forward voltage caused by wafer deformation or misalignment during fabrication when the ohmic contact layer is located inside the metal electrode, further improving the reliability of the entire diode and effectively enhancing the electrochemical corrosion resistance of the entire electrode structure. Simultaneously, by adjusting the material composition of the first metal electrode, a good ohmic contact is formed between the first metal electrode and the first ohmic contact layer, thereby obtaining a stable operating voltage.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: An epitaxial structure having opposing first and second surfaces, the epitaxial structure comprising a first type of semiconductor layer, a light-emitting layer, and a second type of semiconductor layer stacked sequentially; the first type of semiconductor layer includes a first ohmic contact layer located on the first surface side of the epitaxial structure; the material of the first ohmic contact layer is Al. x Ga y InP, where 0≤x≤1 and 0≤y≤1; A first metal electrode is located on a first surface of the epitaxial structure; the first metal electrode includes at least three elements: gold, germanium, and nickel; the nickel content first increases and then decreases along the direction from the bottom surface of the first metal electrode close to the first surface to the top surface; the first metal electrode also includes titanium and platinum; the titanium element is located closer to the first ohmic contact layer on the first metal electrode than the platinum element, and the platinum element is adjacent to the titanium element. The first metal electrode includes a main electrode and a plurality of extended electrodes; the extended electrodes are located on the first ohmic contact layer and are electrically connected to the first ohmic contact layer; from a top view, the projected area of ​​the extended electrodes on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer on the first surface.

2. The light-emitting diode according to claim 1, characterized in that: The extended electrode does not cover the side of the first ohmic contact layer.

3. The light-emitting diode according to claim 1, characterized in that: The main electrode is located on the first ohmic contact layer or on the first surface that is not covered by the first ohmic contact layer.

4. The light-emitting diode according to claim 1, characterized in that: The thickness of the titanium element on the first metal electrode is greater than 800 angstroms.

5. The light-emitting diode according to claim 1, characterized in that: The first ohmic contact layer contains nickel.

6. The light-emitting diode according to claim 1, characterized in that: The first type of semiconductor layer further includes at least one first window layer, the first window layer being located on the side of the first ohmic contact layer away from the first metal electrode; the material of the first window layer is Al. m Ga n InP, where 0≤m≤1 and 0≤n≤1; wherein the Al content in the first ohmic contact layer is less than the Al content in the first window layer.

7. The light-emitting diode according to claim 6, characterized in that: The thickness of the first ohmic contact layer is greater than 300 angstroms and less than the thickness of the first window layer.

8. The light-emitting diode according to claim 6, characterized in that: The thickness of the first window layer is less than 5 μm.

9. The light-emitting diode according to claim 6, characterized in that: The first ohmic contact layer is N-type doped, the first window layer is N-type doped, and the doping concentration of the first window layer is lower than that of the first ohmic contact layer.

10. The light-emitting diode according to claim 9, characterized in that: The doping concentration of the first ohmic contact layer is greater than 4E+18 / cm 3 The doping concentration of the first window layer is 4 E + 17~4 E + 18 / cm. 3 .

11. The light-emitting diode according to claim 6, characterized in that: The Al x Ga y InP and Al m Ga n In InP, mx≥0.

2.

12. The light-emitting diode according to claim 6, characterized in that: The Al x Ga y InP and Al m Ga n In InP, x ranges from 0.2 to 1, and m ranges from 0 to 0.

8.

13. The light-emitting diode according to claim 1, characterized in that: The first surface of the epitaxial structure is either a roughened surface or an unroughened surface.

14. The light-emitting diode according to claim 13, characterized in that: In the epitaxial structure, where the first surface is a roughened surface, the first metal electrode is located on the unroughened surface.

15. The light-emitting diode according to claim 1, characterized in that: The wavelength range emitted by the light-emitting diode is 550~750nm.

16. A light-emitting diode, characterized in that, The light-emitting diode includes: An epitaxial structure having opposing first and second surfaces, the epitaxial structure comprising a first type of semiconductor layer, a light-emitting layer, and a second type of semiconductor layer stacked sequentially; the first type of semiconductor layer includes a first ohmic contact layer located on the first surface side of the epitaxial structure; the material of the first ohmic contact layer is Al. x Ga y InP, where 0≤x≤1 and 0≤y≤1; A first metal electrode is located on a first surface of the epitaxial structure; the first metal electrode includes a main electrode and a plurality of extended electrodes; the extended electrodes are located on the first ohmic contact layer and are electrically connected to the first ohmic contact layer. The first metal electrode comprises at least three elements: gold, germanium, and nickel. The nickel content increases and then decreases along the direction from the bottom surface of the first metal electrode close to the first surface to the top surface. The first metal electrode also comprises titanium and platinum. The titanium element is located closer to the first ohmic contact layer on the first metal electrode than the platinum element, and the platinum element is adjacent to the titanium element.

17. The light-emitting diode according to claim 16, characterized in that: The thickness of the titanium element on the first metal electrode is greater than 800 angstroms.

18. The light-emitting diode according to claim 16, characterized in that: The first ohmic contact layer contains nickel.

19. The light-emitting diode according to claim 16, characterized in that: The first type of semiconductor layer further includes at least one first window layer, the first window layer being located on the side of the first ohmic contact layer away from the first metal electrode; the material of the first window layer is Al. m Ga n InP, where 0≤m≤1 or 0≤n≤1; wherein the Al content in the first ohmic contact layer is less than the Al content in the first window layer.

20. The light-emitting diode according to claim 19, characterized in that: The first ohmic contact layer is N-type doped, the first window layer is N-type doped, and the doping concentration of the first window layer is lower than that of the first ohmic contact layer.

21. The light-emitting diode according to claim 20, characterized in that: The doping concentration of the first ohmic contact layer is greater than 4E+18 / cm 3 The doping concentration of the first window layer is 4 E + 17~4 E + 18 / cm. 3 .

22. The light-emitting diode according to claim 19, characterized in that: The Al x Ga y InP and Al m Ga n In InP, mx≥0.

2.

23. The light-emitting diode according to claim 19, characterized in that: The Al x Ga y InP and Al m Ga n In InP, x ranges from 0.2 to 1, and m ranges from 0 to 0.

8.

24. A light-emitting device, characterized in that: The light-emitting device is a light-emitting diode as described in any one of claims 1-23.

25. A method for manufacturing a light-emitting diode, characterized in that, Including the following steps: An epitaxial structure is prepared, the epitaxial structure having a first surface and a second surface opposite to each other, and comprising a first type semiconductor layer, a light-emitting layer and a second type semiconductor layer sequentially stacked from the first surface to the second surface; The first type of semiconductor layer includes a first ohmic contact layer; the material of the first ohmic contact layer is Al. x Ga y InP, where 0≤x≤1 and 0≤y≤1; A first metal electrode is fabricated on a first surface of an epitaxial structure. The first metal electrode includes a main electrode and a plurality of extended electrodes. The main electrode is deposited on a first ohmic contact layer or on a first surface not covered by the first ohmic contact layer. The first metal electrode includes at least three elements: gold, germanium, and nickel. The nickel content first increases and then decreases along the direction from the bottom surface of the first metal electrode close to the first surface to the top surface. The first metal electrode also includes titanium and platinum. The titanium element is located closer to the first ohmic contact layer on the first metal electrode than the platinum element, and the platinum element is adjacent to the titanium element. The extended electrode is deposited on the first ohmic contact layer, and from a top view, the projected area of ​​the extended electrode on the first surface is less than or equal to the projected area of ​​the first ohmic contact layer on the first surface.

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