Light emitting diode and light emitting device

Abstract

The invention relates to the technical field of semiconductors, and provides a light-emitting diode and a light-emitting device.The light-emitting diode comprises an epitaxial structure, a first electrode and a second electrode; the epitaxial structure comprises a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence; the first electrode is located on the epitaxial structure and electrically connected with the first semiconductor layer; the second electrode is located on the epitaxial structure and is electrically connected with the second semiconductor layer; the first electrode and / or the second electrode are / is of a titanium-free laminated structure. Through the above arrangement, the anti-aging capability of the chip can be improved, and then the reliability of the chip is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a light emitting diode and a light emitting device. Background Art

[0002] Light Emitting Diode (LED) is a semiconductor light-emitting element, usually made of semiconductors such as GaN, GaAs, GaP, GaAsP, etc., and its core is a PN junction with light-emitting characteristics. LED has the advantages of high luminous intensity, high efficiency, small size, and long service life, and is considered to be one of the most promising light sources at present.

[0003] Existing light-emitting diodes generally contain a metal electrode design containing Ti. Ti is prone to cause voids during the preparation process, and has problems such as unstable reliability and extremely high aging abnormality rate. Especially during long-term use, the traditional metal electrode design containing Ti is prone to accelerate the aging speed of LED devices, reduce luminous efficiency, and even cause failure. Therefore, how to improve the anti-aging risk of chips is a major problem that technicians in this field need to solve. Summary of the invention

[0004] In order to solve at least one of the shortcomings of the light emitting diode in the above-mentioned prior art, the purpose of the present application is to provide a light emitting diode that can improve the anti-aging ability of the chip and thus improve the reliability of the chip.

[0005] In a first aspect, the present application provides a light-emitting diode, comprising an epitaxial structure, a first electrode, and a second electrode; the epitaxial structure comprises a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; the first electrode is located on the epitaxial structure and is electrically connected to the first semiconductor layer; the second electrode is located on the epitaxial structure and is electrically connected to the second semiconductor layer; the first electrode and / or the second electrode is a titanium-free stacked structure.

[0006] In a second aspect, the present application provides a light-emitting diode, comprising: an epitaxial structure, a first contact electrode, a first electrode, a second contact electrode, and a second electrode; the epitaxial structure comprises a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; the first contact electrode is located on the epitaxial structure and is electrically connected to the first semiconductor layer; the first electrode is located on the first contact electrode and is electrically connected to the first contact electrode; the second contact electrode is located on the epitaxial structure and is electrically connected to the second semiconductor layer; the second electrode is located on the second contact electrode and is electrically connected to the second contact electrode; at least one of the first contact electrode, the first electrode, the second contact electrode, and the second electrode is a titanium-free stacked structure.

[0007] In a third aspect, the present application also provides a light-emitting device, which uses the light-emitting diode described in the above embodiment.

[0008] Based on the above, compared with the prior art, the light-emitting diode provided in the present application can effectively avoid the problems of unstable reliability and extremely high aging abnormality rate of the electrode by limiting the material of the electrode to a titanium-free laminated structure, thereby improving the reliability and anti-aging ability of the entire chip.

[0009] Other features and beneficial effects of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The positional relationships described in the drawings in the following description are based on the directions in which the components are drawn in the diagrams, unless otherwise specified.

[0011] Figure 1 A cross-sectional view of a light emitting diode provided in an implementation manner of Example 1 of the present application; Figure 2 for Figure 1 A partial enlarged view of middle A; Figure 3 A cross-sectional view of a light emitting diode provided in another implementation manner of Example 1 of the present application; Figure 4 for Figure 3 A schematic diagram of a stacked structure of a first electrode or a second electrode; Figure 5 A schematic diagram of a stacked structure of a first electrode or a second electrode provided in another implementation manner in Example 1 of the present application; Figure 6 A cross-sectional view of a light emitting diode provided in an implementation manner of Example 2 of the present application; Figure 7 for Figure 6 A partial enlarged view of B in the middle; Figure 8 A cross-sectional view of a light emitting diode provided in another embodiment of the second embodiment of the present application; Fig. 9 for Figure 8Schematic diagram of the stacked structure of the first contact electrode or the second contact electrode and the first electrode or the second electrode.

[0012] Reference numerals: 10-epitaxial structure; 11-first semiconductor layer; 12-active layer; 13-second semiconductor layer; 21-first contact electrode; 22-second contact electrode; 20a-first bottom layer; 20b-first top layer; 31-first electrode; 32-second electrode; 30a-second bottom layer; 30b-second top layer; 40-insulating layer; 51-current spreading layer; 52-current blocking layer. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0014] In the description of the present invention, it should be noted that all terms (including technical terms and scientific terms) used in the present invention have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and should not be understood as limitations on the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in this invention.

[0015] To achieve at least one advantage or other advantages in the present application, an embodiment of the present application provides a light-emitting diode, which includes at least an epitaxial structure, a first electrode, and a second electrode; the epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; the first electrode is located on the epitaxial structure and electrically connected to the first semiconductor layer; the second electrode is located on the epitaxial structure and electrically connected to the second semiconductor layer; the first electrode and / or the second electrode is a titanium-free stacked structure.

[0016] By setting the electrode to a titanium-free laminated structure, the electrode has good quality, avoiding the occurrence of holes that may cause water vapor erosion, thereby improving the chip's anti-aging ability and reliability.

[0017] In some embodiments, the titanium-free stack includes a gold layer on the side farthest from the epitaxial structure. The gold layer has excellent electrical conductivity, chemical stability and mechanical strength, helps to improve current injection efficiency, and has good welding performance.

[0018] In some embodiments, the thickness of the gold layer is more than 50% of the thickness of the titanium-free laminate to achieve an effect of easy welding.

[0019] In some embodiments, the titanium-free stack includes a nickel layer, which is at least located on the layer closest to the epitaxial structure; the nickel layer can not only form a good interface with the semiconductor material but also block the doping components from extending from the semiconductor to the electrode.

[0020] In some embodiments, the nickel layer is further located below the gold layer and in direct contact with the gold layer to achieve good adhesion with the gold layer.

[0021] In some embodiments, in the titanium-free stack, the thickness of the nickel layer located on the side closest to the epitaxial structure is thinner than the thickness of other nickel layers, so as to effectively exert their respective functions.

[0022] In some embodiments, in the titanium-free stack, the thickness of the nickel layer closest to the epitaxial structure is less than the thickness of other single layers to reduce resistance, improve contact with the semiconductor layer, and reduce uneven stress distribution.

[0023] In some embodiments, the titanium-free laminate further includes a platinum layer; in the titanium-free laminate, the nickel layer and the platinum layer are alternately stacked with each other, and the number of alternately stacked pairs is between 1 and 5. The alternately stacked nickel layer and platinum layer can reduce the stress in the nickel layer and greatly improve the thermal stability of the electrode.

[0024] In some embodiments, in the titanium-free stack, the total thickness of the nickel layer is not greater than the total thickness of the platinum layer, so as to improve the influence of the stress of the nickel layer and avoid the abnormality of metal warping.

[0025] The present application also provides a light-emitting diode, which comprises at least an epitaxial structure, a first contact electrode, a first electrode, a second contact electrode, and a second electrode; The epitaxial structure includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence; a first contact electrode is located on the epitaxial structure and electrically connected to the first semiconductor layer; a first electrode is located on the first contact electrode and electrically connected to the first contact electrode; a second contact electrode is located on the epitaxial structure and electrically connected to the second semiconductor layer; a second electrode is located on the second contact electrode and electrically connected to the second contact electrode; at least one of the first contact electrode, the first electrode, the second contact electrode and the second electrode is a titanium-free stacked structure.

[0026] The double electrode design formed by adding the first contact electrode and the second contact electrode and using a titanium-free laminated electrode can further effectively protect the contact electrodes and prevent water vapor from entering, thereby greatly reducing the abnormal aging rate of the light-emitting diode and increasing the service life of the light-emitting diode.

[0027] In some embodiments, the first contact electrode and / or the second contact electrode includes a first bottom layer closest to a side of the epitaxial structure and a first top layer farthest from a side of the epitaxial structure.

[0028] In some embodiments, the first bottom layer and the first top layer are the same metal material.

[0029] In some embodiments, the first bottom layer and the first top layer both include a nickel layer; the thickness of the first top layer is not greater than the thickness of the first bottom layer. Through the above arrangement, the contact resistance can be reduced, the current transmission efficiency can be improved, and the thermal stability of the electrode can also be improved.

[0030] In some embodiments, the first contact electrode and / or the second contact electrode further includes a platinum layer, and the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of alternating stacking is between 1 and 5 pairs, so as to improve the thermal stability of the electrode and effectively relieve the stress in the nickel layer.

[0031] In some embodiments, the total thickness of the platinum layer on the first contact electrode or the second contact electrode is more than 50% of the thickness of the first contact electrode or the second contact electrode, so that the electrode has better mechanical strength and corrosion resistance, and also helps to reduce electromigration.

[0032] In some embodiments, in the first contact electrode and / or the second contact electrode, the thickness of the single-layer nickel layer located between the first top layer and the first bottom layer is greater than the thickness of the nickel layer located in the first top layer or the first bottom layer, so as to effectively play the different roles of the nickel layers in each layer.

[0033] In some embodiments, the thickness of the first contact electrode and / or the second contact electrode is between 500 and 3500 angstroms.

[0034] In some embodiments, the first electrode and / or the second electrode includes a second top layer farthest from a side of the epitaxial structure and a second bottom layer closest to a side of the epitaxial structure.

[0035] In some embodiments, the thickness of the second top layer is more than 50% of the thickness of the first electrode or the second electrode where the second top layer is located, thereby facilitating welding.

[0036] In some embodiments, the first bottom layer and the second bottom layer are made of the same metal material to effectively control current distribution while reducing stress caused by differences in thermal expansion coefficients, and / or, the first top layer and the second bottom layer are made of the same metal material, so that the same materials can be more tightly combined at the interface, thereby improving connection strength and reducing resistance.

[0037] In some embodiments, the second bottom layer comprises a nickel layer and the second top layer comprises a gold layer.

[0038] In some embodiments, the first electrode and / or the second electrode further includes a platinum layer, the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of the alternate stacking is between 1 and 4 pairs.

[0039] In some embodiments, the thickness of the first electrode is greater than the thickness of the first contact electrode, the thickness of the second electrode is greater than the thickness of the second contact electrode, and the thickness of the first electrode and the second electrode is between 1 and 3 μm. This configuration helps improve electrical properties and thermal management.

[0040] In some embodiments, the light emitting diode further includes an insulating layer, wherein the insulating layer covers the epitaxial structure and at least partially covers a sidewall of the epitaxial structure.

[0041] In some embodiments, the insulating layer includes a stacked first insulating layer, a second insulating layer, and a third insulating layer, the thickness of the first insulating layer is less than the thickness of the second insulating layer, the thickness of the second insulating layer is less than the thickness of the third insulating layer; the thickness of the first insulating layer is less than or equal to 100 angstroms. By designing the multi-layer insulating layer, it is possible to further resist the entry of water vapor, effectively achieve electrical isolation, and improve anti-aging ability.

[0042] In some embodiments, the size of the light emitting diode is less than or equal to 150 μm.

[0043] The present application also provides a light-emitting device, which uses the light-emitting diode described in any of the above embodiments to improve the performance of the light-emitting device.

[0044] The technical solution of the present application will be clearly and completely described below through a variety of specific implementation methods in conjunction with the drawings in the embodiments of the present application.

[0045] Embodiment 1 See also Figure 1 , Figure 1 1 is a cross-sectional view of a light emitting diode provided in an embodiment of the present application. The light emitting diode provided in this embodiment at least includes an epitaxial structure 10 , a first electrode 31 , and a second electrode 32 .

[0046] The epitaxial structure 10 is disposed on a substrate. The substrate may be an insulating substrate. Preferably, the substrate may be made of a transparent material or a semi-transparent material. For example, the substrate is a sapphire substrate or a patterned sapphire substrate. The substrate may also be made of a conductive material or a semiconductor material. For example, the material of the substrate may include at least one of silicon carbide, silicon, magnesium aluminum oxide, magnesium oxide, lithium aluminum oxide, aluminum gallium oxide, and gallium nitride.

[0047] The epitaxial structure 10 includes a first semiconductor layer 11, an active layer 12, and a second semiconductor layer 13 stacked in sequence. The first semiconductor layer 11 may be an N-type semiconductor layer, which may provide electrons to the active layer 12 under the action of a power source. In some embodiments, the first semiconductor layer 11 includes an N-type doped nitride layer. The N-type doped nitride layer may include one or more N-type impurities of group IV elements. The N-type impurities may include one or a combination of Si, Ge, and Sn.

[0048] The active layer 12 may be a quantum well structure (QuantumWell, referred to as QW). In some embodiments, the active layer 12 may also be a multiple quantum well structure (MultipleQuantumWell, referred to as MQW), wherein the multiple quantum well structure includes multiple quantum well layers (Well) and multiple quantum barrier layers (Barrier) alternately arranged in a repeated manner, for example, a multiple quantum well structure of GaN / AlGaN, InAlGaN / InAlGaN or InGaN / AlGaN. In addition, the composition and thickness of the well layer in the active layer 12 determine the wavelength of the generated light. In order to improve the luminous efficiency of the active layer 12, it can be achieved by changing the depth of the quantum well, the number of layers, thickness and / or other characteristics of the paired quantum wells and quantum barriers in the active layer 12.

[0049] The second semiconductor layer 13 can be a P-type semiconductor layer, which can provide holes to the active layer 12 under the action of a power supply. In some embodiments, the second semiconductor layer 13 includes a P-type doped nitride layer. The P-type doped nitride layer may include one or more P-type impurities of Group II elements. The P-type impurities may include one or a combination of Mg, Zn, and Be. The second semiconductor layer 13 can be a single-layer structure or a multi-layer structure, and the multi-layer structure has different compositions. In addition, the setting of the epitaxial structure 10 is not limited thereto, and epitaxial structures of other functions or types can be selected according to actual needs.

[0050] Please continue reading Figure 1, the first electrode 31 is located on the epitaxial structure 10 and is electrically connected to the first semiconductor layer 11; the second electrode 32 is located on the epitaxial structure 10 and is electrically connected to the second semiconductor layer 13. In some embodiments, a current spreading layer 51 may be provided between the electrode and the epitaxial structure 10 to further improve the conductivity and enhance the photoelectric characteristics of the light-emitting diode. A current blocking layer 52 may also be provided under the electrode to suppress the current gathering phenomenon near the electrode and improve the current spreading performance. For example Figure 6 In the embodiment, a current spreading layer 51 and a current blocking layer 52 are arranged between the second electrode 32 and the epitaxial structure 10. The current blocking layer 52 is located within the orthographic projection range of the current spreading layer 51.

[0051] Furthermore, the light-emitting diode further includes an insulating layer 40, which covers the epitaxial structure 10 and at least covers a portion of the sidewall of the epitaxial structure 10. The insulating layer 40 has different functions according to the position involved. For example, when the insulating layer 40 covers the sidewall of the epitaxial structure 10, it can be used to prevent the first semiconductor layer 11 and the second semiconductor layer 13 from being electrically connected due to leakage of conductive materials, thereby reducing the possibility of short circuit abnormalities of the light-emitting diode, but the embodiments of the present disclosure are not limited thereto.

[0052] As a preferred solution, in this embodiment, the insulating layer 40 includes a first insulating layer, a second insulating layer and a third insulating layer stacked in sequence. Among them, the thickness of the first insulating layer is less than the thickness of the second insulating layer, and the thickness of the second insulating layer is less than the thickness of the third insulating layer. The first insulating layer, the second insulating layer, and the third insulating layer can be a silicon oxide passivation layer, an organic passivation layer, a DBR stacked reflective layer, etc. composed of dielectric materials. They are stacked on each other according to actual application needs and technical requirements to achieve different performance goals. Through the multi-layer stacked insulating layer 40, it is possible to further resist the entry of water vapor, effectively achieve electrical isolation, and improve anti-aging ability.

[0053] As an example, the first insulating layer is an ALD layer, the second insulating layer is a PECVD layer, and the third insulating layer is a DBR stack. Among them, the ALD layer is a uniform and high-quality insulating interface film formed by atomic layer deposition (ALD) to protect the chip structure from environmental factors. In this embodiment, the material of the ALD layer is preferably aluminum oxide. Preferably, the thickness of the ALD layer is less than or equal to 100 angstroms, such as 50 angstroms, to avoid the ALD layer being too thick, resulting in over-etching in the subsequent etching process, causing damage to the DBR stack, improving electrical insulation performance, and preventing current leakage. The PECVD layer is an insulating film with good mechanical strength and electrical insulation formed by plasma-enhanced chemical vapor deposition (PECVD). In this embodiment, the material of the PECVD layer is preferably silicon oxide or silicon nitride. As an example, the thickness of the PECVD layer is greater than the thickness of the ALD layer to provide better mechanical protection and higher insulation resistance. In this embodiment, the thickness of the PECVD layer is preferably between 1000 and 5000 angstroms, such as 2000 angstroms. The DBR stack (Distributed Bragg Reflector) includes a structure composed of multiple layers of materials with different refractive indices alternating with each other, which is used to reflect light of a specific wavelength. It not only serves as an insulator, but also plays an optical role in improving the light extraction efficiency. The material of the DBR stack is, for example, silicon dioxide and titanium dioxide, which are periodically stacked. In this embodiment, the thickness of the DBR stack is preferably greater than the thickness of the PECVD layer to ensure that the DBR stack has sufficient reflective effect. The thickness of the DBR stack is greater than 5000 angstroms, for example, 8000 angstroms. The above-mentioned design of the specific insulating layer 40 can effectively protect the electrode from water vapor erosion, thereby greatly improving the anti-aging performance of the chip.

[0054] Traditional metal electrodes are generally designed with titanium materials. This design meets the basic light-emitting area of ​​the LED to a certain extent. However, since the titanium material is easily corroded and causes holes during the subsequent etching process, the light-emitting diode has unstable reliability and extremely high aging abnormality rate during long-term use.

[0055] Based on the above, the present embodiment designs the first electrode 31 and the second electrode 32 to solve the above problems. Specifically, in the present embodiment, the first electrode 31 and / or the second electrode 32 is a titanium-free laminated structure, so that the electrode has good quality, avoids the occurrence of holes and causes water vapor erosion, fundamentally solves the problem of abnormal aging, and improves the reliability of the light-emitting diode.

[0056] In a preferred embodiment, the titanium-free laminate includes a gold layer on the side farthest from the epitaxial structure 10. The gold layer has excellent electrical conductivity, chemical stability and mechanical strength, and has good welding performance. Placing it in the outermost layer of the titanium-free laminate helps to improve the current injection efficiency and prevent the electrode material from being corroded during manufacturing and use, thereby improving the performance and reliability of the device. In order to ensure that the gold layer has the above-mentioned good properties and achieve the effect of easy welding, the thickness of the gold layer in this embodiment is preferably more than 50% of the thickness of the titanium-free laminate. More preferably, the thickness of the gold layer is more than 60% or 80% to 90% of the thickness of the titanium-free laminate.

[0057] In addition, in the first electrode 31 or the second electrode 32, the outermost gold layer is arranged to cover the laminated structures below the gold layer, thereby protecting the laminated structures below the gold layer, and effectively realizing the anti-oxidation and anti-corrosion of the electrode. In specific implementation, only the gold layer may cover the laminated structures below, such as Figure 4 As shown, each layer can also be coated from top to bottom in sequence, such as Figure 5 As shown, the good function of the electrodes is further ensured. At the same time, the cross-sectional outer contour of the first electrode 31 and / or the second electrode 32 can be set as follows Figure 4 Rectangular shape as shown or Figure 5 The trapezoidal shape with a slope shown can of course be set to other regular or irregular shapes according to actual needs, and the present embodiment is not limited thereto.

[0058] In another preferred embodiment, please continue to refer to Figure 2 , Figure 4 , Figure 5 , the titanium-free stack includes a nickel layer, and the nickel layer is at least located at the layer closest to the epitaxial structure 10. Among them, if the layer uses conventional chromium as a contact layer (usually a layer in direct contact with the semiconductor layer), it is easy to cause an extremely high aging abnormality rate. Therefore, in this embodiment, the layer closest to the epitaxial structure 10 uses a nickel layer. The nickel layer can not only form a good interface with the semiconductor material and reduce interface defects, but also serve as an extended barrier layer to prevent or reduce the diffusion of doping components from the semiconductor layer to the metal layer. In addition, the nickel layer also has good heat dissipation, electrical conductivity, water vapor resistance and aging resistance, and can effectively resist high temperature aging while ensuring electrical conductivity. Of course, the layer closest to the epitaxial structure 10 can also use other materials, such as Nb.

[0059] Preferably, the nickel layer is also located below the gold layer and in direct contact with the gold layer, so that the gold layer and the nickel layer below can form good adhesion, which helps to enhance the mechanical stability of the entire metal stack. Of course, the layer structure in direct contact with the gold layer can also be other materials besides the nickel layer, such as a copper layer, an aluminum layer, etc.

[0060] Furthermore, in the titanium-free stack, the thickness of the nickel layer closest to the epitaxial structure 10 is less than the thickness of other single layers. By providing a thinner nickel layer as a contact layer, the resistance can be reduced, the contact effect with the semiconductor layer can be improved, and the current transmission efficiency of the light-emitting diode can be improved. At the same time, the heat conduction can be effectively controlled, the uneven stress distribution caused by the mismatch of the thermal expansion coefficient can be reduced, and the risk of damage to the semiconductor layer can be reduced.

[0061] The titanium-free stack may further include an intermediate layer between the bottom layer and the top layer, and the material of the intermediate layer may be a Ni / Pt stack. As an example, the thickness of the bottom layer is between 10 and 50 angstroms.

[0062] Preferably, please continue to see Figure 2 , Figure 4 , Figure 5 , the titanium-free laminate further includes a platinum layer; in the titanium-free laminate, the nickel layer and the platinum layer are stacked alternately with each other, and the number of pairs of alternating stacking is between 1 and 5 pairs. By arranging the alternating stacking of nickel layers and platinum layers, the thermal stability of the electrode can be greatly improved, and it can be used in high temperature environments for a long time, thereby improving the service life of the device. And because the nickel layer has greater stress than other metal layers, the alternating nickel layers and platinum layers can reduce the stress in the nickel layer. At the same time, the thickness of the nickel layer is further adjusted, and the total thickness of the nickel layer is set not greater than the total thickness of the platinum layer, so as to further improve the influence of the stress of the nickel layer and avoid subsequent abnormalities of gold warping, thereby improving the quality of the electrode.

[0063] Furthermore, in the titanium-free laminate, the thickness of the nickel layer on the side closest to the epitaxial structure 10 is less than the thickness of other nickel layers. Based on the different functions of the nickel layer on the side closest to the epitaxial structure 10 and other nickel layers, the thickness of the nickel layer on the side closest to the epitaxial structure 10 is adjusted to be less than the thickness of other nickel layers, so that their respective functions can be effectively exerted. Specifically, a thinner nickel layer is provided on the side closest to the epitaxial structure 10 to reduce the thermal stress generated by the difference in thermal expansion coefficient between it and the epitaxial structure 10, thereby improving the stability and reliability of the electrode. A thicker nickel layer is provided at other locations on the titanium-free laminate to provide sufficient mechanical strength, conductivity and corrosion resistance.

[0064] More preferably, the size of the light emitting diode in the first embodiment is preferably less than or equal to 150 μm. That is, the present embodiment is not only applicable to conventional LEDs, but also to Micro LEDs, so as to effectively improve the high temperature, high humidity and aging resistance of Micro LEDs.

[0065] Embodiment 2 See also Figure 6, which is different from the first embodiment, the second embodiment adopts a double-layer electrode structure, that is, a first contact electrode 21 is added between the first electrode 31 and the epitaxial structure 10, and a second contact electrode 22 is added between the second electrode 32 and the epitaxial structure 10. In a specific implementation, the light-emitting diode includes the epitaxial structure 10, the first contact electrode 21, the first electrode 31, the second contact electrode 22, and the second electrode 32.

[0066] The epitaxial structure 10 includes a first semiconductor layer 11, an active layer 12, and a second semiconductor layer 13 stacked in sequence; the first contact electrode 21 is located on the epitaxial structure 10 and is electrically connected to the first semiconductor layer 11; the second contact electrode 22 is located on the epitaxial structure 10 and is electrically connected to the second semiconductor layer 13. Of course, this embodiment also includes an insulating layer 40, and the insulating layer 40 also includes a first insulating layer, a second insulating layer, and a third insulating layer. The functions and characteristics of the above structures can be referred to the description of the first embodiment, and will not be repeated here.

[0067] In this embodiment, the first electrode 31 is located on the first contact electrode 21 and electrically connected to the first contact electrode 21; the second electrode 32 is located on the second contact electrode 22 and electrically connected to the second contact electrode 22. Among them, at least one of the first contact electrode 21, the first electrode 31, the second contact electrode 22, and the second electrode 32 is a titanium-free laminated structure. That is, the material of the double-layer electrode does not contain titanium.

[0068] The double electrode design formed by adding the first contact electrode 21 and the second contact electrode 22 and using a titanium-free laminated electrode can further effectively protect the electrode and prevent water vapor from entering, thereby significantly reducing the abnormal aging rate of the light-emitting diode and increasing the service life of the light-emitting diode.

[0069] Optionally, the thickness of the first electrode 31 is greater than the thickness of the first contact electrode 21, and the thickness of the second electrode 32 is greater than the thickness of the second contact electrode 22. The first electrode 31 and the second electrode 32 that are thicker than the first contact electrode 21 and the second contact electrode 22 can not only provide a larger current capacity, but also help optimize the distribution of current in the electrode, while providing a better heat conduction path to improve thermal management; it can also better resist mechanical stress during manufacturing and use. As an example, the thickness of the first electrode 31 and the second electrode 32 is between 1 and 3 μm. The thickness of the first contact electrode 21 and / or the second contact electrode 22 is between 500 and 3500 angstroms.

[0070] As a preferred solution, the first contact electrode 21 and / or the second contact electrode 22 includes a first bottom layer 20a closest to the epitaxial structure 10 and a first top layer 20b farthest from the epitaxial structure 10. The thickness of the first top layer 20b is not greater than the thickness of the first bottom layer 20a. Specifically, the first top layer 20b needs to be in contact with the first electrode 31 or the second electrode 32. By setting the first top layer 20b thinner than the first bottom layer 20a, the contact resistance can be reduced, the current transmission efficiency can be improved, and the thermal stability of the electrode can be improved. In addition, by controlling the thinner thickness of the first top layer 20b, the influence of the etching rate on the electrode structure can be avoided.

[0071] Further, the first bottom layer 20a and the first top layer 20b are made of the same metal material. As an example, the first bottom layer 20a and the first top layer 20b both include a nickel layer to prevent the laminated material between the first bottom layer 20a and the first top layer 20b from diffusing outwards, and to prevent the outer material from diffusing into the first bottom layer 20a and the first top layer 20b. In addition, the material of the first bottom layer 20a can also be chromium, and the laminated material between the first bottom layer 20a and the first top layer 20b includes, but is not limited to, metals or alloys such as aluminum, copper, nickel, and platinum.

[0072] As another preferred solution, the first contact electrode 21 and / or the second contact electrode 22 further comprises a platinum layer, and the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of alternate stacking is between 1 and 5. Specifically, this arrangement can not only greatly improve the thermal stability of the electrode, but also help to relieve the stress in the nickel layer. And the alternate stacking can improve the distribution of current in the electrode and reduce local hot spots.

[0073] Preferably, the total thickness of the platinum layer on the first contact electrode 21 or the second contact electrode 22 is more than 50% of the thickness of the first contact electrode 21 or the second contact electrode 22. Pt has better mechanical strength and wear resistance than Ni. By setting the total thickness of the platinum layer to be more than 50% of the thickness of the entire electrode, the mechanical stability of the electrode can be improved, deformation during manufacturing and use can be prevented, and electromigration can also be reduced.

[0074] Further, in the first contact electrode 21 and / or the second contact electrode 22, the thickness of the single nickel layer between the first top layer 20b and the first bottom layer 20a is greater than the thickness of the nickel layer in the first top layer 20b or the first bottom layer 20a. This arrangement can effectively play the different roles of the nickel layers in each layer. Specifically, the thinner nickel layer in the first top layer 20b and the first bottom layer 20a can reduce stress and contact resistance; while the thicker single nickel layer between the first top layer 20b and the first bottom layer 20a can provide sufficient mechanical strength, conductivity and corrosion resistance.

[0075] In other optional embodiments, the first electrode 31 and / or the second electrode 32 include a second top layer 30b on the side farthest from the epitaxial structure 10 and a second bottom layer 30a on the side closest to the epitaxial structure 10. In this embodiment, the second bottom layer 30a preferably includes a nickel layer and the second top layer 30b includes a gold layer. The nickel layer selected for the second bottom layer 30a has good adhesion, which can ensure good adhesion between the stacked layers and prevent them from falling off during subsequent process steps or device use; at the same time, it can also improve the interface characteristics between the double-layer electrodes, reduce the interface resistance, and prevent the mutual diffusion of materials between the double-layer electrodes. The gold layer selected for the second top layer 30b has excellent electrical conductivity, chemical stability, mechanical strength and good welding performance.

[0076] In this embodiment, the thickness of the second top layer 30b is preferably more than 50% of the thickness of the first electrode 31 or the second electrode 32 where the second top layer 30b is located, so as to facilitate welding. More preferably, the thickness of the second top layer 30b is more than 60% or 80% to 90% of the thickness of the first electrode 31 or the second electrode 32 where the second top layer 30b is located.

[0077] Of course, the second bottom layer 30a and the second top layer 30b may also be made of other metals or alloy layers, for example, the second bottom layer 30a may be made of tungsten, tantalum, etc., and the second top layer 30b may be made of platinum or tin, but this embodiment is not limited thereto. In this embodiment, it is preferred that the second bottom layer 30a does not include chromium. Since the contact property of chromium is relatively poor, it is easy to have a voltage rise in the second bottom layer 30a of the first electrode 31 or the second bottom layer 30a of the second electrode 32, resulting in high voltage, and it is easy to transfer under high temperature and high pressure, resulting in chromium failure. Therefore, it is preferred that the second bottom layer 30a includes a nickel layer, which has good contact property and will not have the above problems.

[0078] Preferably, the first bottom layer 20a and the second bottom layer 30a are made of the same metal material, and / or, the first top layer 20b and the second bottom layer 30a are made of the same metal material. Among them, setting the first bottom layer 20a and the second bottom layer 30a to the same metal material can effectively control the current distribution while reducing the stress caused by the difference in thermal expansion coefficient. In addition, setting the first top layer 20b and the second bottom layer 30a to the same metal material allows the same materials to be more tightly combined at the interface, enhancing the connection strength between the first electrode 31 and the first contact electrode 21 or between the second electrode 32 and the second contact electrode 22, and helping to prevent interface peeling or failure due to mechanical application or chemical corrosion during use; at the same time, the first top layer 20b and the second bottom layer 30a of the same metal material can provide a smoother current transition at the interface, reduce resistance and energy loss, and help ensure uniform distribution of current in the laminated structure. In this embodiment, it is preferred that the first bottom layer 20a, the first top layer 20b, and the second bottom layer 30a include a nickel layer to effectively improve performance.

[0079] The first electrode 31 and / or the second electrode 32 further include a platinum layer, and the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of alternate stacking is between 1 and 4 pairs. As an example, the first electrode 31 and / or the second electrode 32 may form a Ni / Pt / Au structure. In this embodiment, it is preferred that the number of pairs of alternate stacking of the nickel layer and the platinum layer in the first contact electrode 21 is less than the number of pairs of alternate stacking of the nickel layer and the platinum layer in the first electrode 31, and / or the number of pairs of alternate stacking of the nickel layer and the platinum layer in the second contact electrode 22 is less than the number of pairs of alternate stacking of the nickel layer and the platinum layer in the second electrode 32.

[0080] Of course, the laminate between the second bottom layer 30a and the second top layer 30b is not limited to nickel layer and platinum layer, and can also be other metals or alloys such as copper, tungsten, etc. In this embodiment, it is preferred that the middle bottom layer does not contain aluminum material.

[0081] In addition, in the first electrode 31 and the second electrode 32, the outermost second top layer 30b is configured to cover the stacked structures below the second top layer 30b, thereby protecting the stacked layers and effectively realizing the anti-oxidation and anti-corrosion of the electrodes. In specific implementation, only the second top layer 30b may cover the stacked layers below, such as Fig. 9 As shown, each stacking layer may be covered sequentially from top to bottom to further ensure the good function of the electrode. Similarly, in the first contact electrode 21 and the second contact electrode 22, each stacking layer structure may not be covered, or only the first top layer 20b may cover the following stacking layers, or each stacking layer may be covered sequentially from top to bottom, for example Fig. 9 shown.

[0082] Meanwhile, the cross-sectional outer contours of the first electrode 31 , the second electrode 32 , the first contact electrode 21 , and the second contact electrode 22 can be set to a rectangular shape or a trapezoidal shape with a slope, and can of course be set to other regular or irregular shapes according to actual needs, and the present embodiment is not limited thereto.

[0083] Similarly, in the second embodiment, the size of the light emitting diode is preferably less than or equal to 150 μm. That is, the present embodiment is not only applicable to conventional LEDs, but also to Micro LEDs, so as to effectively improve the high temperature, high humidity and aging resistance of Micro LEDs.

[0084] Embodiment 3 The present invention also provides a light emitting device, which uses the light emitting diode described in any of the above embodiments to effectively improve the performance of the light emitting device. The specific structure, function and effect of the light emitting diode can be referred to above and will not be repeated here.

[0085] In summary, compared with the prior art, the light-emitting diode and the light-emitting device provided by the present invention can effectively prevent water vapor from entering the interior of the light-emitting diode during long-term use through the structure and material design of the electrode, greatly improve the anti-aging ability of the chip, and have good reliability.

[0086] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0087] Although the terms such as epitaxial structure, first contact electrode, second contact electrode, first electrode, second electrode, etc. are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention; the terms "first" and "second" in the description and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 comprises: An epitaxial structure comprises a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence; a first electrode, located on the epitaxial structure and electrically connected to the first semiconductor layer; a second electrode, located on the epitaxial structure and electrically connected to the second semiconductor layer; The first electrode and / or the second electrode is a titanium-free laminated structure.

2. The light emitting diode according to claim 1, characterized in that: The titanium-free stack includes a gold layer on a side farthest from the epitaxial structure.

3. The light emitting diode according to claim 2, characterized in that: The thickness of the gold layer is more than 50% of the thickness of the titanium-free laminate.

4. The light emitting diode according to claim 2, characterized in that: The titanium-free stack includes a nickel layer, and the nickel layer is at least located at a layer closest to a side of the epitaxial structure.

5. The light emitting diode according to claim 4, characterized in that: The nickel layer is also located below the gold layer and in direct contact with the gold layer.

6. The light emitting diode according to claim 5, characterized in that: In the titanium-free stack, the thickness of the nickel layer located on the side closest to the epitaxial structure is smaller than the thickness of other nickel layers.

7. The light emitting diode according to claim 4, characterized in that: In the titanium-free stack, the thickness of the nickel layer closest to the epitaxial structure is smaller than the thickness of other single layers.

8. The light emitting diode according to claim 4, characterized in that: The titanium-free laminate further includes a platinum layer. In the titanium-free laminate, the nickel layer and the platinum layer are alternately stacked, and the number of alternately stacked pairs is between 1 and 5 pairs.

9. The light emitting diode according to claim 8, characterized in that: In the titanium-free stack, the total thickness of the nickel layers is no greater than the total thickness of the platinum layers.

10. A light emitting diode, characterized in that: The light emitting diode comprises: An epitaxial structure comprises a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence; a first contact electrode, located on the epitaxial structure and electrically connected to the first semiconductor layer; a first electrode, located on the first contact electrode and electrically connected to the first contact electrode; a second contact electrode, located on the epitaxial structure and electrically connected to the second semiconductor layer; a second electrode, located on the second contact electrode and electrically connected to the second contact electrode; At least one of the first contact electrode, the first electrode, the second contact electrode, and the second electrode is a titanium-free laminated structure.

11. The light emitting diode according to claim 10, characterized in that: The first contact electrode and / or the second contact electrode includes a first bottom layer closest to a side of the epitaxial structure and a first top layer farthest from a side of the epitaxial structure.

12. The light emitting diode according to claim 11, characterized in that: The first bottom layer and the first top layer are made of the same metal material.

13. The light emitting diode according to claim 11, characterized in that: The first bottom layer and the first top layer both include a nickel layer; and the thickness of the first top layer is not greater than the thickness of the first bottom layer.

14. The light emitting diode according to claim 13, characterized in that: The first contact electrode and / or the second contact electrode further includes a platinum layer, and the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of the alternate stacking is between 1 and 5 pairs.

15. The light emitting diode according to claim 14, characterized in that: The total thickness of the platinum layer on the first contact electrode or the second contact electrode is more than 50% of the thickness of the first contact electrode or the second contact electrode.

16. The light emitting diode according to claim 14, characterized in that: In the first contact electrode and / or the second contact electrode, the thickness of the single nickel layer between the first top layer and the first bottom layer is greater than the thickness of the nickel layer in the first top layer or the first bottom layer.

17. The light emitting diode according to claim 10, characterized in that: The thickness of the first contact electrode and / or the second contact electrode is between 500 and 3500 angstroms.

18. The light emitting diode according to claim 11, characterized in that: The first electrode and / or the second electrode includes a second top layer farthest from the epitaxial structure and a second bottom layer closest to the epitaxial structure.

19. The light emitting diode according to claim 13, characterized in that: The thickness of the second top layer is more than 50% of the thickness of the first electrode or the second electrode where the second top layer is located.

20. The light emitting diode according to claim 18, characterized in that: The first bottom layer and the second bottom layer are made of the same metal material, and / or the first top layer and the second bottom layer are made of the same metal material.

21. The light emitting diode according to claim 18, characterized in that: The second bottom layer includes a nickel layer and the second top layer includes a gold layer.

22. The light emitting diode according to claim 21, characterized in that: The first electrode and / or the second electrode further includes a platinum layer, and the nickel layer and the platinum layer are alternately stacked with each other, and the number of pairs of the alternate stacking is between 1 and 4 pairs.

23. The light emitting diode according to claim 10, characterized in that: The thickness of the first electrode is greater than that of the first contact electrode, and the thickness of the second electrode is greater than that of the second contact electrode; the thickness of the first electrode and the second electrode is between 1 and 3 μm.

24. The light emitting diode according to claim 1 or 10, characterized in that: The light emitting diode further includes an insulating layer, which covers the epitaxial structure and at least partially covers a side wall of the epitaxial structure.

25. The light emitting diode according to claim 24, characterized in that: The insulating layer includes a stacked first insulating layer, a second insulating layer and a third insulating layer, the thickness of the first insulating layer is less than the thickness of the second insulating layer, the thickness of the second insulating layer is less than the thickness of the third insulating layer; the thickness of the first insulating layer is less than or equal to 100 angstroms.

26. The light emitting diode according to claim 1 or 10, characterized in that: The size of the light emitting diode is less than or equal to 150 μm.

27. A light emitting device, characterized in that: A light emitting diode as described in any one of claims 1 to 26 is used.

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