Light emitting diode and light emitting device

Abstract

The invention belongs to the technical field of semiconductor manufacturing, and provides a light-emitting diode and a light-emitting device.The light-emitting diode comprises an epitaxial lamination layer, an insulating layer and a connecting electrode, the epitaxial lamination layer comprises a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence, and a groove hole is formed in the epitaxial lamination layer; the connecting electrode comprises a first electrode electrically connected with the first semiconductor layer and a second electrode electrically connected with the second semiconductor layer, the first electrode comprises a first electrode layer and a second electrode layer formed on the first electrode layer and the surface of the first semiconductor layer exposed by the slotted hole, and the first electrode layer comprises a first contact layer in contact with the insulating layer; the second electrode layer comprises a second contact layer in contact with the second semiconductor layer, the thickness of the second contact layer is smaller than that of the first contact layer, the adhesion of the first electrode is improved through the first contact layer with the larger thickness, the reflection effect of the first electrode is improved through the second contact layer with the smaller thickness, and the light-emitting effect of the light-emitting diode is enhanced.

Description

Technical Field

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

[0002] Light Emitting Diode (LED) is a semiconductor solid-state light-emitting device. With the continuous development of semiconductor technology, the luminous efficiency of LEDs has been continuously improved, making LEDs one of the most valued light sources in recent years. Commercial LED packaging initially used a positive structure that connected the chip PN junction with the positive and negative electrodes of the bracket with gold wire. However, positive structure LEDs have problems such as large light attenuation, light quenching and heat dissipation, which restricts the development of positive structure LEDs. Based on this, researchers have successively developed vertical structure LEDs and flip-chip structure LEDs.

[0003] Among them, flip-chip light-emitting diodes can be integrated and mass-produced, with a simple preparation process and excellent performance. Flip-chip light-emitting diodes eutectically bond the PN junction to the positive and negative electrodes on the substrate without using gold wires, which improves the problem of light quenching. The heat generated by the light emission can be directly conducted to the heat sink without passing through the contrast, thereby improving the heat dissipation effect. The interconnection between the chip and the substrate shortens the electrical path, speeds up signal transmission, reduces response delays, and improves overall performance.

[0004] However, in a flip-chip light-emitting diode, in order to achieve the connection between the metal electrode and the light-emitting structure, a through hole is opened in the light-emitting structure to expose the bottom N-type semiconductor layer. The metal electrode is electrically connected to the N-type semiconductor layer via the through hole. Since the metal layer and the reflective layer of the light-emitting diode cannot cover the through hole, the light extraction efficiency of the light-emitting diode will inevitably be reduced during use, thereby affecting the light-emitting effect of the light-emitting diode. Summary of the invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of the present application is to provide a light emitting diode and a light emitting device, which are used to improve the light extraction efficiency of the light emitting diode and enhance the light emitting effect.

[0006] In order to achieve the above-mentioned and other related purposes, the present application provides a light emitting diode, including:

[0007] An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer;

[0008] an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole;

[0009] A connecting electrode is formed on the insulating layer, comprising a first electrode and a second electrode, the first electrode being electrically connected to the first electrode layer via the fifth through hole, the second electrode being electrically connected to the second semiconductor layer via the fourth through hole, the first electrode comprising a first electrode layer formed on the insulating layer and a second electrode layer partially formed on the first electrode layer, the second electrode layer also comprising a portion of the surface of the first semiconductor layer exposed by the slot through the fifth through hole, the first electrode layer comprising a first contact layer in contact with the insulating layer, and the second electrode layer comprising a second contact layer in contact with the surface of the first semiconductor layer; wherein the thickness of the second contact layer is less than the thickness of the first contact layer.

[0010] On the other hand, the present application also provides a light emitting diode, comprising:

[0011] An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer;

[0012] an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole;

[0013] A connecting electrode is formed on the insulating layer, including a first electrode and a second electrode, the first electrode is electrically connected to the first semiconductor layer via the fifth through hole, and the second electrode is electrically connected to the second semiconductor layer via the fourth through hole, the first electrode includes a contact layer, the contact layer includes a first contact portion formed on the insulating layer and a second contact portion formed on the surface of the first semiconductor layer exposed by the slot, and the thickness of the second contact portion is less than the thickness of the first contact portion.

[0014] On the other hand, the present application further provides a light-emitting device, including a circuit substrate and a plurality of light-emitting elements connected to the circuit substrate, wherein the light-emitting elements include the light-emitting diode described in the present application.

[0015] As described above, the light emitting diode and light emitting device provided by the present application have at least the following beneficial effects:

[0016] In the first aspect, the light-emitting diode of the present application includes an epitaxial stack, an insulating layer and a connecting electrode, the connecting electrode includes a first electrode and a second electrode, the first electrode is electrically connected to the first semiconductor layer, the first electrode includes a contact layer, the contact layer includes a first contact portion and a second contact portion, the first contact portion is formed on the insulating layer, the second contact portion is formed on the surface of the first semiconductor layer exposed by the slot, the thickness of the first contact portion is greater than the thickness of the second contact portion, the relatively thin first contact portion effectively improves the reflectivity of the first electrode, and the relatively thick second contact portion can ensure good adhesion between the first electrode and the insulating layer, thereby ensuring that the light-emitting diode has good structural stability and working reliability.

[0017] On the second aspect, in the light-emitting diode of the present application, the first electrode includes a first electrode layer and a second electrode layer, the first electrode layer is formed on the insulating layer, the second electrode layer is formed on the first electrode layer and on the surface of the first semiconductor layer exposed by the slot, the first electrode layer includes a first contact layer in contact with the insulating layer, and the second electrode layer includes a second contact layer in contact with the surface of the first semiconductor layer. By making the thickness of the second contact layer smaller than the thickness of the first contact layer, the reflectivity of the first electrode is further improved, so that the light-emitting diode has a better light extraction efficiency. At the same time, the relatively thick second contact layer can ensure good adhesion between the first electrode and the insulating layer, thereby ensuring the structural stability and working reliability of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 Shown is a schematic diagram of the structure of a light emitting diode provided in Example 1 of the present application.

[0020] Figure 1a to Figure 1d Shown as Figure 1 A partial enlarged view of regions M1 to M4 in the light emitting diode is shown.

[0021] Figure 2 Display as Figure 1 Schematic diagram of the structure of the epitaxial stack in the light-emitting diode shown.

[0022] Figure 3 Display as Figure 1 A schematic structural diagram of the first insulating layer in a light emitting diode is shown.

[0023] Figure 4 Display as Figure 1 A schematic diagram of the top view structure of the connecting electrodes in the light emitting diode shown.

[0024] Figure 5 Display as Figure 2 Schematic diagram of the top view structure of the epitaxial stack shown.

[0025] Figure 6 Shown is a schematic diagram of a curve showing a change in reflectivity and wavelength of the connecting electrode provided in the first embodiment of the present application.

[0026] Figure 7 Display as Figure 1 The schematic diagram of the top view structure of the light emitting diode shown.

[0027] Figure 8 Display as Figure 7 An enlarged view of the structure of region M5 in the light-emitting diode is shown.

[0028] Fig. 9 Shown is a schematic structural diagram of a transparent conductive layer in a light-emitting diode provided in Example 1 of the present application.

[0029] Fig.10 Display as Fig. 9 Schematic diagram of the top view structure of the transparent conductive layer shown.

[0030] Fig.11 Shown is a schematic structural diagram of the second insulating layer in the light emitting diode provided in the first embodiment of the present application.

[0031] Fig.12 Display as Fig.11 A schematic top view of the structure of the second insulating layer is shown.

[0032] Fig.13 Shown is a schematic structural diagram of a metal layer in a light-emitting diode provided in Example 1 of the present application.

[0033] Fig.14 Shown is a schematic diagram of the structure of a light emitting diode provided in Example 2 of the present application.

[0034] Fig.14a and Fig.14b Shown as Fig.14 A partial enlarged view of regions M6 and M7 in the light emitting diode is shown.

[0035] Fig.15 Shown is a schematic diagram of the top view structure of the transparent conductive layer in the light emitting diode provided in the third embodiment of the present application.

[0036] Fig.16 Shown is a schematic structural diagram of a light emitting diode with a metal barrier layer provided in Example 4 of the present application.

[0037] Fig.17 Shown is a schematic structural diagram of a first insulating layer having an insulating barrier layer provided in Embodiment 5 of the present application.

[0038] Fig.18 Shown is a schematic diagram of the structure of the light-emitting device provided in Example 6 of the present application.

[0039] Reference numerals:

[0040] 10. substrate; 20. epitaxial stack; 21. first semiconductor layer; 22. active layer; 23. second semiconductor layer; 241. slot; 242. recess; 240. edge table; 30. connection electrode; 31. first electrode; 301. contact layer; 3011. first contact portion; 3012. second contact portion; 302. metal reflective layer; 311. first electrode layer; 3111. first contact layer; 3112. first metal reflective layer; 312. second electrode layer; 3121. second contact layer; 3122. second metal reflective layer; 32. second electrode; 321. third electrode layer; 3211. third contact layer; 3212. a third metal reflective layer; 322, a fourth electrode layer; 3221, a fourth contact layer; 3222, a fourth metal reflective layer; 41, a transparent conductive layer; 411, a third through hole; 42, a second insulating layer; 421, a first through hole; 422, a second through hole; 51, a metal layer; 52, a metal barrier layer; 60, an insulating layer; 61, a first insulating layer; 611, a fourth through hole; 612, a fifth through hole; 601, an insulating barrier layer; 6011, a sixth through hole; 62, a third insulating layer; 621, an opening; 71, a pad electrode; 711, a first pad layer; 712, a second pad layer; 80, a light-emitting device; 81, a light-emitting element; 82, a circuit substrate. DETAILED DESCRIPTION

[0041] The following describes the implementation of the present application through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in the present application specification. The present application can also be implemented or applied through other different specific implementations, and the details in the present application can also be modified, changed or combined in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0042] In the description of the present application, it should be noted that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance; the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only used to facilitate the description and simplify the description of the present application, and cannot be understood as limiting the present application; the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, they can be fixed connections or detachable connections; when a layer is referred to as "between" two layers, it can be the only layer between the two layers, or there can be one or more layers in between. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0043] In view of the problem of low light extraction efficiency of light-emitting diodes in the prior art, in order to improve the light-emitting effect of light-emitting diodes, this embodiment provides a light-emitting diode, including:

[0044] An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer;

[0045] an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole;

[0046] The connecting electrode is formed on the insulating layer, and includes a first electrode and a second electrode. The first electrode is electrically connected to the first electrode layer via the fifth through hole, and the second electrode is electrically connected to the second semiconductor layer via the fourth through hole. The first electrode includes a first electrode layer formed on the insulating layer and a second electrode layer partially formed on the first electrode layer. The second electrode layer also includes a portion of the surface of the first semiconductor layer exposed by the slot through the fifth through hole. The first electrode layer includes a first contact layer in contact with the insulating layer, and the second electrode layer includes a second contact layer in contact with the surface of the first semiconductor layer; wherein the thickness of the second contact layer is less than that of the first contact layer. The second contact layer has a relatively small thickness, which effectively improves the reflectivity of the first electrode to light, so that the light-emitting diode has a better light extraction efficiency; the first contact layer has a relatively large thickness, so that it has better adhesion, thereby improving the adhesion effect of the first electrode, and ensuring that the light-emitting diode has good structural stability and working reliability.

[0047] Optionally, the first contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the first contact layer is

[0048] The second contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the second contact layer is

[0049] Optionally, the first electrode layer further includes a first metal reflective layer formed on the first contact layer, and the second electrode layer further includes a second metal reflective layer formed on the second contact layer, and the thickness of the first metal reflective layer is equal to the thickness of the second metal reflective layer. The first contact layer and the second contact layer respectively form a reflective structure with the first metal reflective layer and the second metal reflective layer, thereby improving the reflective effect of the first electrode. By controlling the thickness of the first contact layer and the second contact layer, the absorption of light can be reduced, and the light extraction effect of the light-emitting diode can be enhanced.

[0050] Optionally, the reflectivity of the first electrode layer is less than the reflectivity of the second electrode layer. The first electrode layer can be set to have a relatively small reflectivity to ensure that the first electrode can have a relatively thick first contact layer, thereby ensuring good adhesion between the first electrode and the insulating layer, and at the same time having a certain reflection effect on light; the second electrode layer has a relatively large reflectivity, which can further reflect the light passing through the first electrode layer, while ensuring that the first electrode has good adhesion, and at the same time ensuring that the first electrode has an excellent reflection effect on light, thereby improving the light extraction efficiency of the light-emitting diode.

[0051] Optionally, the second electrode layer has a first portion in contact with the first electrode layer, and a second portion in contact with the first semiconductor layer, and in a top view of the light-emitting diode along the thickness direction of the epitaxial stack, the area of ​​the first portion is larger than the area of ​​the second portion. By making the area of ​​the first portion larger than the area of ​​the second portion, a larger contact area can be provided between the first electrode layer and the second electrode layer, thereby ensuring good adhesion between the first electrode layer and the second electrode layer and improving the structural stability of the light-emitting diode.

[0052] Optionally, a plurality of recessed portions are further provided at the periphery of the epitaxial stack, and the recessed portions penetrate the second semiconductor layer, the active layer and part of the first semiconductor layer along the thickness direction of the epitaxial stack to expose part of the surface of the first semiconductor layer, and the second electrode layer contacts the surface of the first semiconductor layer exposed by the recessed portions via the fifth through hole. By providing the recessed portions at the periphery of the epitaxial stack, the diffusion of the current can be enhanced and the uniformity of the internal field strength can be improved.

[0053] Optionally, it further comprises a substrate, the epitaxial stack is formed on the substrate;

[0054] In the top view of the light-emitting diode, the distance between the first electrode layer and the edge of the substrate is greater than the distance between the second electrode layer and the edge of the substrate, the distance between the edge of the first electrode layer and the edge of the second electrode layer is the electrode layer edge spacing, and the value of the electrode layer edge spacing in the area where the recessed portion is located is greater than the value of the electrode layer edge spacing in other areas of the light-emitting diode. By making the second electrode layer completely cover the edge of the first electrode layer, it is ensured that the light passing through the first electrode layer can be effectively reflected, thereby improving the light extraction efficiency of the light-emitting diode, and by regulating the electrode layer edge spacing, the electrical connection effect between the second electrode layer and the first semiconductor layer exposed in the recessed portion can be ensured, thereby improving the performance of the light-emitting diode.

[0055] Optionally, the second electrode includes a third electrode layer and a fourth electrode layer, the third electrode layer includes a third contact layer formed on the insulating layer, the fourth electrode layer includes a fourth contact layer formed on the third electrode layer, and the thickness of the third contact layer is greater than the thickness of the fourth contact layer. The thicker third contact layer can ensure the adhesion effect between the second electrode and the insulating layer, and the thinner fourth contact layer effectively improves the reflectivity of the second electrode, thereby improving the light extraction efficiency of the light-emitting diode.

[0056] Optionally, there is a first gap between the first electrode layer and the third electrode layer, and a second gap between the second electrode layer and the fourth electrode layer, and the width of the first gap is smaller than the width of the second gap; the first electrode can be prevented from contacting the second electrode, ensuring electrical insulation between the first electrode and the second electrode.

[0057] Optionally, the third electrode layer further includes a third metal reflective layer formed on the third contact layer, the fourth electrode layer further includes a fourth metal reflective layer formed on the fourth contact layer, and the thickness of the third metal reflective layer is equal to the thickness of the fourth metal reflective layer.

[0058] Optionally, the third contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the third contact layer is

[0059] The fourth contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the fourth contact layer is The third contact layer and the fourth contact layer form a total reflection structure with the third metal reflection layer and the fourth metal reflection layer respectively, thereby improving the reflectivity of the second electrode. By controlling the thickness of the third contact layer and the fourth contact layer, the absorption of light can be reduced and the light extraction effect of the light-emitting diode can be enhanced.

[0060] This embodiment also provides another light emitting diode, including:

[0061] An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer;

[0062] an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole;

[0063] The connecting electrode is formed on the insulating layer, and includes a first electrode and a second electrode. The first electrode is electrically connected to the first semiconductor layer via the fifth through hole, and the second electrode is electrically connected to the second semiconductor layer via the fourth through hole. The first electrode includes a contact layer, and the contact layer includes a first contact portion formed on the insulating layer and a second contact portion formed on the surface of the first semiconductor layer exposed by the slot, and the thickness of the second contact portion is less than the thickness of the first contact portion. The relatively thin first contact portion effectively improves the reflectivity of the first electrode, and the relatively thick second contact portion can ensure good adhesion between the first electrode and the insulating layer, thereby ensuring that the light-emitting diode has good structural stability and working reliability.

[0064] Optionally, in the top view of the light emitting diode, the area of ​​the first contact portion is larger than the area of ​​the second contact portion. By making the area of ​​the first contact portion larger than the area of ​​the second contact portion, a larger contact area can be provided between the first electrode and the insulating layer, thereby ensuring good adhesion between the first electrode and the insulating layer and improving the structural stability of the light emitting diode.

[0065] Optionally, the light emitting diode further includes a transparent conductive layer and a metal layer, and the insulating layer includes a first insulating layer and a second insulating layer:

[0066] The transparent conductive layer is formed on the epitaxial stack; it can enhance the diffusion effect of current and improve the performance of the light emitting diode;

[0067] The second insulating layer is formed on the epitaxial stack and covers the transparent conductive layer. The second insulating layer has a first through hole and a second through hole. The first through hole exposes the transparent conductive layer, and the second through hole exposes the surface of the first semiconductor layer exposed by the slot.

[0068] The metal layer is formed on the second insulating layer and contacts the transparent conductive layer via the first through hole;

[0069] The first insulating layer is formed on the metal layer and covers the second insulating layer. The second insulating layer can enhance the uniformity of current distribution and can also serve as a reflective structure for light radiated from the epitaxial stack. The metal layer can achieve electrical connection between the second electrode and the second semiconductor layer, has a good light reflection effect, and cooperates with the second insulating layer to form a light reflection structure to improve light extraction efficiency.

[0070] Optionally, a plurality of third through holes spaced apart from each other are provided in the transparent conductive layer, the third through holes expose the second semiconductor layer, and are arranged in a staggered manner with the first through holes. By providing a plurality of third through holes, the absorption effect of the transparent conductive layer on the light radiated by the active layer can be reduced, thereby improving the light extraction efficiency and light emitting effect of the light emitting diode.

[0071] Optionally, the light-emitting diode further includes a metal barrier layer formed on the second insulating layer and covering the metal layer, the fourth through hole exposes the metal barrier layer, and the second electrode contacts the metal barrier layer via the fourth through hole. The metal barrier layer can prevent the components of the metal layer from being diffused by heat or migrated by electricity, and prevent the metal layer surface from being oxidized, resulting in a decrease in the reflectivity of the metal layer, thereby ensuring the working reliability of the light-emitting diode.

[0072] Optionally, the second insulating layer includes an insulating barrier layer covering the metal layer, a sixth through hole is provided in the insulating barrier layer, and the second electrode contacts the metal layer via the fourth through hole and the sixth through hole. The insulating barrier layer can prevent the components of the metal layer from being diffused by heat or migrated by electricity, and prevent the metal layer surface from being oxidized, resulting in a decrease in the reflectivity of the metal layer, thereby ensuring the working reliability of the light-emitting diode.

[0073] Optionally, the light emitting diode further comprises:

[0074] a third insulating layer, located on a side of the first insulating layer away from the second insulating layer, covering the connecting electrode, and having an opening exposing the connecting electrode;

[0075] The pad electrode is located at a side of the connection electrode away from the first insulating layer and is electrically connected to the connection electrode via the opening.

[0076] This embodiment also provides a light emitting device, including a circuit substrate and a plurality of light emitting elements connected to the circuit substrate, wherein the light emitting elements include any of the light emitting diodes described in the above embodiments. Since the light emitting device includes the light emitting diodes described in this application, it also has the above beneficial effects.

[0077] The present application scheme will be described in detail below in conjunction with specific embodiments.

[0078] Embodiment 1

[0079] This embodiment provides a light emitting diode, referring to Figure 1 , including an epitaxial stack 20, an insulating layer 60 and a connecting electrode 30. The epitaxial stack 20 is a light-emitting structure of a light-emitting diode, which can radiate light of a specific wavelength, such as blue light with a wavelength of 450nm, yellow light with a wavelength of 550nm or red light with a wavelength of 620nm. The connecting electrode 30 is electrically connected to the epitaxial stack 20.

[0080] Reference Figure 2 The epitaxial stack 20 includes a first semiconductor layer 21, an active layer 22, and a second semiconductor layer 23 stacked in sequence, and a slot 241 is provided in the epitaxial stack 20, and the slot 241 penetrates the second semiconductor layer 23, the active layer 22, and a portion of the first semiconductor layer 21 to expose a portion of the surface of the first semiconductor layer 21. Optionally, the first semiconductor layer 21 has a first surface and a second surface that are arranged opposite to each other, the second surface is a surface of the first semiconductor layer 21 close to the active layer 22 and connected to the active layer 22, the first surface is a surface of the first semiconductor layer 21 away from the active layer 22, and the slot 241 exposes the second surface of the first semiconductor layer 21; further, the shape of the slot 241 can be circular, elliptical, rectangular, polygonal or other acceptable shapes.

[0081] In an optional embodiment, the first semiconductor layer 21, the active layer 22, and the second semiconductor layer 23 may be semiconductor layers made of compounds of the III-group gallium nitride series, such as GaN, AlN, InGaN, AlGaN, InAlGaN, and one or more of the above materials. The first semiconductor layer 21, the active layer 22, and the second semiconductor layer 23 may be made by a chemical vapor deposition process, a hydride vapor phase epitaxy process, a molecular beam epitaxy process, or other acceptable methods. The first semiconductor layer 21 and the second semiconductor layer 23 have different conductivity types and can provide electrons and holes, respectively. For example, the first semiconductor layer 21 is an N-type semiconductor layer, and the second semiconductor layer 23 is a P-type semiconductor layer, or the first semiconductor layer 21 is a P-type semiconductor layer, and the second semiconductor layer 23 is an N-type semiconductor layer. The active layer 22 is a layer that combines electrons and holes to output light of a specific wavelength. The active layer 22 can be formed by a multilayer semiconductor film having a single-layer or multi-layer quantum well structure in which potential well layers and potential barrier layers are alternately stacked. The active layer 22 adjusts the wavelength of the output light by controlling the material ratio or component composition.

[0082] Furthermore, the first semiconductor layer 21 is an N-type semiconductor layer, which can provide electrons. The first semiconductor layer 21 can be formed by injecting N-type dopants such as Si, Ge, Se, Te, C and other materials. The second semiconductor layer 23 is a P-type semiconductor layer, which can provide holes. The second semiconductor layer 23 can be formed by injecting P-type dopants such as Mg, Zn, Be, Ca, Sr, Ba and other materials.

[0083] In this embodiment, refer to Figure 1 and Figure 3 The insulating layer 60 is formed on the epitaxial stack 20 and is located between the connecting electrode 30 and the epitaxial stack 20. The fourth through hole 611 and the fifth through hole 612 are provided in the insulating layer 60. The thickness direction of the epitaxial stack 20 is the vertical direction. Optionally, in the top view of the light-emitting diode along the vertical direction, the contour structure of the fourth through hole 611 and the fifth through hole 612 can be circular, elliptical, polygonal or other suitable structures.

[0084] In an optional embodiment, the insulating layer 60 includes a first insulating layer 61, the first insulating layer 61 is located between the connecting electrode 30 and the epitaxial stack 20, and the material of the first insulating layer 61 includes a material that is transparent to the light radiated by the active layer 22; optionally, the material of the first insulating layer 61 includes SiO 2 、SiN、SiO x N y 、TiO 2 、Si 3 N 4 、Al 2 O 3 , TiN, AlN and other transparent inorganic insulating materials, for example, the first insulating layer 61 is SiO 2 further, the first insulating layer 61 can be formed by a physical vapor deposition process or a chemical vapor deposition process and the like to form the first insulating layer 61, and then the first insulating layer 61 is patterned by photolithography and etching to form a fourth through hole 611 and a fifth through hole 612.

[0085] Reference Figure 1 and Figure 4The connecting electrode 30 is formed on the insulating layer 60 and is located on the side of the second semiconductor layer 23 away from the active layer 22. The connecting electrode 30 includes a first electrode 31 and a second electrode 32. The second electrode 32 is electrically connected to the second semiconductor layer 23, and the first electrode 31 is electrically connected to the first semiconductor layer 21. Optionally, the first semiconductor layer 21 is an N-type semiconductor layer, and the first electrode 31 can conduct electrons to the first semiconductor layer 21. The second semiconductor layer 23 is a P-type semiconductor layer, and the second electrode 32 can conduct holes to the second semiconductor layer 23. The first electrode 31 includes a first electrode layer 311 and a second electrode layer 312. The first electrode layer 311 is formed on the first insulating layer 61, and the second electrode layer 312 is formed on the first electrode layer 311 and on the first semiconductor layer 21 exposed by the slot 241. Optionally, in the top view of the light-emitting diode, the second electrode layer 312 completely covers the first electrode layer 311. The second electrode layer 312 contacts the surface of the first semiconductor layer 21 via the fifth through hole 612, referring to Figure 1a and Figure 1b The first electrode layer 311 includes a first contact layer 3111 in contact with the first insulating layer 61 , and the second electrode layer includes a second contact layer 3121 in contact with the surface of the first semiconductor layer 21 , and the thickness of the second contact layer 3121 is less than the thickness of the first contact layer 3111 .

[0086] In an optional embodiment, the connection electrode 30 may be a single-layer structure or a laminated structure, and the material of the connection electrode 30 includes a metal material, such as titanium (Ti), tungsten (W), aluminum (Al), indium (In), tin (Sn), nickel (Ni), platinum (Pt), chromium (Cr), gold (Au), titanium tungsten (TiW) and other metals or one or more of the above materials. Further, the connection electrode 30 adopts a laminated structure, and the first contact layer 3111 and the second contact layer 3121 are respectively the first layers of the laminated structure of the first electrode layer 311 and the laminated structure of the second electrode layer 312, and have good adhesion, and are used to fix the positions of the first electrode layer 311 and the second electrode layer 312 in the light-emitting diode, thereby ensuring the structural stability of the light-emitting diode.

[0087] In the prior art, when the connecting electrode adopts a laminated structure, the first layer of the laminated structure usually has a large thickness, and the large thickness of the first layer will reduce the reflection effect of the connecting electrode, thereby reducing the light extraction efficiency of the light-emitting diode. In this embodiment, the first electrode 31 includes a first electrode layer 311 and a second electrode layer 312, the first electrode layer 311 includes a first contact layer 3111, and the second electrode layer 312 includes a second contact layer 3121. The thickness of the first contact layer 3111 is greater than that of the second contact layer 3121. The relatively thin second contact layer 3121 can improve the reflection effect of the first electrode 31 on light while ensuring good ohmic contact between the first electrode 31 and the first semiconductor layer 21, thereby enhancing the light extraction efficiency of the light-emitting diode. The first contact layer 3111 has a relatively thick thickness, which improves the adhesion effect between the first electrode 31 and the first insulating layer 61, thereby ensuring that the light-emitting diode has good structural stability and working reliability.

[0088] In an optional embodiment, the first contact layer 3111 is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the first contact layer 3111 is Optionally, the thickness of the first contact layer 3111 can be, for example, or other suitable values. Further, the first contact layer 3111 is a metal chromium layer. The second contact layer 3121 is a metal chromium layer, a metal nickel layer or a metal titanium layer. The thickness of the second contact layer 3121 is Optionally, the thickness of the second contact layer 3121 can be, for example, or other suitable values, further, the second contact layer 3121 is a metal chromium layer. In practical applications, the metal chromium layer, the metal nickel layer, and the metal titanium layer have good adhesion, especially the metal chromium layer. By setting the first contact layer 3111 of suitable thickness, the absorption of light can be reduced to the maximum extent while ensuring the adhesion effect between the first contact layer 3111 and the first insulating layer 61. The thinner second contact layer 3121 can improve the reflection effect of the first electrode 31 on light, thereby improving the light emitting effect, structural stability and working reliability of the light emitting diode.

[0089] In an alternative embodiment, reference Figure 5, a plurality of recessed portions 242 are further provided at the periphery of the epitaxial stack 20, and the recessed portions 242 penetrate the second semiconductor layer 23, the active layer 22 and part of the first semiconductor layer 21 in the vertical direction to expose part of the surface of the first semiconductor layer 21, and the second electrode layer 312 contacts the surface of the first semiconductor layer 21 exposed by the recessed portions 242 via the fifth through hole 612. Optionally, the number of slots 241 and the number of recessed portions 242 are both multiple, and the multiple slots 241 are arranged at intervals in the epitaxial stack 20, and the multiple recessed portions 242 are arranged at intervals at the periphery of the epitaxial stack 20. By providing multiple slots 241 and recessed portions 242 spaced apart from each other, the diffusion of current can be enhanced and the uniformity of the internal field strength can be improved.

[0090] In this embodiment, refer to Figure 1 The light emitting diode also includes a substrate 10, which is located on a side of the first semiconductor layer 21 away from the active layer 22. The material of the substrate 10 can be a transparent material. Optionally, the material of the substrate 10 is sapphire, gallium nitride, silicon carbide, gallium arsenide or other suitable materials. Further, the material of the substrate 10 includes sapphire, which has good light transmittance and conductivity.

[0091] In an alternative embodiment, reference Figure 2 and Figure 5 An edge terrace 240 is formed on the periphery of the epitaxial stack 20, and the edge terrace 240 exposes the second surface of the first semiconductor layer 21. The epitaxial stack 20 can be patterned by photolithography and etching to form the edge terrace 240, the slot 241 and the recess 242. In the top view of the light-emitting diode, the recess 242 is closer to the center area of ​​the light-emitting diode than the edge terrace 240 at other positions.

[0092] In an optional embodiment, in the top view of the light-emitting diode, the distance between the first electrode layer 311 and the edge of the substrate 10 is greater than the distance between the second electrode layer 312 and the edge of the substrate 10, and the distance between the edge of the first electrode layer 311 and the edge of the second electrode layer 312 is the electrode layer edge spacing, and the electrode layer edge spacing in the area where the recess 242 is located is greater than the electrode layer edge spacing in other areas of the light-emitting diode. By making the second electrode layer 312 completely cover the edge of the first electrode layer 311, it is possible to ensure effective reflection of light passing through the first electrode layer 311, improve the light extraction efficiency of the light-emitting diode, and by regulating the electrode layer edge spacing, the electrical connection effect between the second electrode layer 312 and the first semiconductor layer 21 exposed in the recess 242 is ensured, thereby improving the performance of the light-emitting diode.

[0093] In this embodiment, both the first electrode layer 311 and the second electrode layer 312 are stacked structures, and the first electrode layer 311 and the second electrode layer 312 can be formed respectively by physical vapor deposition process, magnetron sputtering process or other suitable methods.

[0094] In an alternative embodiment, reference Figure 1a and Figure 1b , the first electrode layer 311 further includes a first metal reflective layer 3112 formed on the first contact layer 3111, and the second electrode layer 312 further includes a second metal reflective layer 3122 formed on the second contact layer 3121. Optionally, the thickness of the first metal reflective layer 3112 is equal to or substantially equal to the thickness of the second metal reflective layer 3122, and substantially equal can be understood as the difference ratio between the two is not more than 10%, for example, the absolute value of the difference between the thickness of the first metal reflective layer 3112 and the thickness of the second metal reflective layer 3122 and the thickness of the second metal reflective layer 3122 is less than 10%; further, the first metal reflective layer 3112 and the second metal reflective layer 3122 are both metal silver layers. The first metal reflective layer 3112 and the first contact layer 3111, as well as the second metal reflective layer 3122 and the second contact layer 3121, all cooperate to form a reflective structure, which improves the reflection effect of the first electrode 31 and enhances the light-emitting effect of the light-emitting diode.

[0095] In an optional embodiment, the reflectivity of the first electrode layer 311 is less than the reflectivity of the second electrode layer 312. The first electrode layer 311 can be set to have a relatively small reflectivity, which can ensure that the first electrode 31 has a relatively thick first contact layer 3111, thereby ensuring that the first electrode 31 has a good adhesion effect with the first insulating layer 61, and at the same time has a certain reflection effect on light; the second electrode layer 312 has a relatively large reflectivity, which can further reflect the light passing through the first electrode layer 311, and ensure that the first electrode 31 has good adhesion and excellent reflection effect on light, thereby improving the light extraction efficiency of the light-emitting diode.

[0096] Furthermore, the reflectivity of the first electrode layer 311 is 78% to 90%, and the reflectivity of the second electrode layer 312 is 89% to 95%. Figure 6 For example, the first contact layer 3111 and the second contact layer 3121 are both metal chromium layers, and the thickness of the first contact layer 3111 is The thickness of the second contact layer 3121 is set to A comparative example made of other materials is set, for example, Al is used as the first layer of the comparative example, and the reflectivity of the first electrode layer 311, the second electrode layer 312 and the comparative example is tested to obtain the reflectivity of different wavelengths, wherein the reflectivity of the first electrode layer 311 to 450nm blue light is 83.2%, and the reflectivity to 620 red light is 91.1%, and the reflectivity of the second electrode layer 312 to 450nm blue light is 89.2%, and the reflectivity to 620 red light is 94.3%. It can be seen that for light with a wavelength of 450nm and above, the thinner second electrode layer 312 has a more excellent reflection effect, therefore, by setting a thinner second contact layer 3121, the reflectivity of the connecting electrode 30 is improved, and the light extraction efficiency of the light emitting diode is enhanced.

[0097] In an alternative embodiment, reference Figure 7 and Figure 8 The second electrode layer 312 has a first portion in contact with the first electrode layer 311 and a second portion in contact with the first semiconductor layer 21, and the area of ​​the first portion is greater than the area of ​​the second portion; optionally, in the top view of the light-emitting diode, the ratio between the area of ​​the first portion and the area of ​​the second electrode layer 312 is greater than 80%. By making the second electrode layer 312 and the first electrode layer 311 have a larger contact area, the first electrode layer 311 and the first insulating layer 61 also have a larger contact area, which effectively ensures that the first electrode layer 311 and the second electrode layer 312 and the first electrode layer 311 and the first insulating layer 61 have good adhesion effects, thereby improving the structural stability of the light-emitting diode.

[0098] In this embodiment, refer to Figure 1c and Figure 1d The second electrode 32 includes a third electrode layer 321 and a fourth electrode layer 322. The second electrode 32 can be made of the same material as the first electrode 31, or can be made of a different material. The third electrode layer 321 includes a third contact layer 3211 formed on the first insulating layer 61, and the fourth electrode layer 322 includes a fourth contact layer 3221 formed on the third electrode layer 321. The thickness of the third contact layer 3211 is greater than the thickness of the fourth contact layer 3221. Similar to the first electrode 31, the relatively thick third electrode layer 321 can improve the adhesion effect between the second electrode 32 and the first insulating layer 61, and the relatively thin fourth electrode layer 322 can improve the reflection effect of the second electrode 32, thereby enhancing the light-emitting effect of the light-emitting diode.

[0099] In an optional embodiment, the third contact layer 3211 is a metal chromium layer, a metal nickel layer or a metal titanium layer. For example, the third contact layer 3211 can be set as a metal chromium layer. The thickness of the third contact layer 3211 is Optionally, the thickness of the third contact layer 3211 may be, for example, or other suitable values; the fourth contact layer 3221 is a metal chromium layer, a metal nickel layer or a metal titanium layer. For example, the fourth contact layer 3221 can be set to a metal chromium layer, and the thickness of the fourth contact layer 3221 is Optionally, the thickness of the fourth contact layer 3221 may be, for example, By controlling the thickness of the third contact layer 3211 and the thickness of the fourth contact layer 3221 , the absorption of light by the second electrode can be reduced, thereby enhancing the light extraction efficiency of the light emitting diode.

[0100] In this embodiment, the structure of the second electrode 32 may be a single-layer structure or a stacked-layer structure. Optionally, the third electrode layer 321 and the fourth electrode layer 322 are both stacked-layer structures, the third electrode layer 321 further includes a third metal reflective layer 3212 formed on the third contact layer 3211, and the fourth electrode layer 322 further includes a fourth metal reflective layer 3222 formed on the fourth contact layer 3221; further, the thickness of the fourth metal reflective layer 3222 is equal to or substantially equal to the thickness of the third metal reflective layer 3212, and the third metal reflective layer 3212 and the fourth metal reflective layer 3222 may be, for example, a metal silver layer or other suitable material layer. A reflective structure is formed between the third metal reflective layer 3212 and the third contact layer 3211, and between the fourth metal reflective layer 3222 and the fourth contact layer 3221, so as to ensure that the second electrode 32 has a good reflection effect and enhance the light extraction efficiency of the light-emitting diode.

[0101] In an alternative embodiment, reference Figure 7 In the top view of the light emitting diode, the area of ​​the third electrode layer 321 is larger than the area of ​​the fourth electrode layer 322. Optionally, there is a first gap between the first electrode layer 311 and the third electrode layer 321, and there is a second gap between the second electrode layer 312 and the fourth electrode layer 322. The width of the first gap is smaller than the width of the second gap. By controlling the width of the first gap and the width of the second gap, the first electrode 31 and the second electrode 32 are spaced apart to ensure electrical insulation between the two.

[0102] In this embodiment, refer to Fig. 9 and Fig.10The light emitting diode may further include a transparent conductive layer 41, which is located on the side of the second semiconductor layer 23 away from the active layer 22. The transparent conductive layer 41 is formed on the second semiconductor layer 23 and covers at least part of the surface of the second semiconductor layer 23. Optionally, the transparent conductive layer 41 may be formed on the second semiconductor layer 23 by a chemical vapor deposition process, a physical vapor deposition process or other acceptable methods, and forms an ohmic contact with the second semiconductor layer 23. The transparent conductive layer 41 may enhance the diffusion effect of the current and improve the performance of the light emitting diode. The material of the transparent conductive layer 41 includes a material that is transparent to the light radiated by the epitaxial stack 20. Optionally, the transparent conductive layer 41 includes ITO, InO, SnO, CTO, ATO, ZnO, GaP or a combination of one or more of the above materials. Further, the thickness of the transparent conductive layer 41 is 5nm to 100nm.

[0103] In this embodiment, refer to Fig.11 and Fig.12 In the light emitting diode, the insulating layer 60 may further include a second insulating layer 42, which is located on a side of the second semiconductor layer 23 away from the active layer 22 and covers at least a portion of the transparent conductive layer 41. Optionally, the second insulating layer 42 is formed on the epitaxial stack 20 and covers the exposed surface of the transparent conductive layer 41 and the epitaxial stack 20. The material of the second insulating layer 42 includes a material that is transparent to the light radiated by the epitaxial stack 20. Optionally, the material of the second insulating layer 42 includes SiO 2 、SiN、SiO x N y 、TiO 2 、Si 3 N 4 、Al 2 O 3 , TiN, AlN and other transparent inorganic insulating materials, for example, the second insulating layer 42 is SiO 2 layer.

[0104] The second insulating layer 42 is provided with a first through hole 421 and a second through hole 422. In the top view of the light-emitting diode, the outline structure of the first through hole 421 and the second through hole 422 can be circular, elliptical, polygonal or other suitable structures. The first through hole 421 penetrates the second insulating layer 42 in the vertical direction and exposes the second semiconductor layer 23. The second through hole 422 is located directly above the slot 241 in the vertical direction to expose at least part of the second surface located in the slot 2414. Optionally, the number of the first through holes 421 is multiple, and in the top view of the light-emitting diode, the multiple first through holes 421 are distributed in the second insulating layer 42 in an array-like interval. After the second insulating layer 42 is formed, the second insulating layer 42 can be patterned by photolithography and etching to form the first through hole 421 to expose the second semiconductor layer 23, or to form the second through hole 422 to expose the second surface. In the top view of the light-emitting diode, the fifth through hole 612 at least partially overlaps with the second through hole 422. Optionally, in the top view of the light-emitting diode, the fifth through hole 612 coincides with the second through hole 422. The fifth through hole 612 and the second through hole 422 can be formed by an etching process.

[0105] In an optional embodiment, the second insulating layer 42 includes a distributed Bragg layer (DBR), and the DBR layer is a multilayer structure in which insulating films with different refractive indices are alternately stacked. Optionally, the DBR layer at least covers the transparent conductive layer 41, and the multilayer structure of the DBR layer is a structure in which a first insulating film with a first refractive index and a second insulating film with a second refractive index are alternately stacked. Further, the second insulating layer 42 is formed of a material having a refractive index lower than the refractive index of the second semiconductor layer 23, which is used to improve the reflection effect of light, thereby improving the light extraction efficiency. The second insulating layer 42 can also be a DBR layer and SiO 2 Layer stacking structure, SiO 2 The layer is formed on the DBR layer.

[0106] In this embodiment, refer to Figure 1 and Fig.13The light emitting diode may further include a metal layer 51, a first insulating layer 61 is formed on the metal layer 51 and covers the second insulating layer 42, the metal layer 51 is formed on the second insulating layer 42 and is located between the first insulating layer 61 and the second insulating layer 42, the second electrode 32 contacts the metal layer 51 via the fourth through hole 611, and the metal layer 51 is electrically connected to the transparent conductive layer 41 via the first through hole 421, so that the current applied to the metal layer 51 can diffuse through the transparent conductive layer 41. Part of the light radiated by the epitaxial stack 20 passes through the second insulating layer 42 to reach the surface of the metal layer 51 and is reflected by the metal layer 51. Optionally, the refractive index of the second insulating layer 42 is less than the refractive index of the epitaxial stack 20, so that part of the light radiated by the active layer 22 can be incident on the metal layer 51 at a small angle, and the light exceeding the total reflection angle is totally reflected back, and a more excellent reflection effect is achieved through the cooperation of the metal layer 51 and the second insulating layer 42. Optionally, the metal layer 51 is a single-layer or multi-layer structure formed of a metal material, for example, it can be formed of one or more materials such as Au, W, Pt, Ir, Ag, Al, Cu, Ni, Ti, Cr and their alloys.

[0107] In an optional embodiment, in the top view of the light-emitting diode, the distance between the metal layer 51 and the edge of the substrate 10 is greater than the distance between the transparent conductive layer 41 and the edge of the substrate 10, so that the contact area between the transparent conductive layer 41 and the second semiconductor layer 23 is greater than the area of ​​the metal layer 51, thereby reducing the voltage. Optionally, in the top view of the light-emitting diode, the first through hole 421 is located within the projection range of the metal layer 51, so that the metal layer 51 can be electrically connected to the transparent conductive layer 41 via the first through hole 421.

[0108] In this embodiment, refer to Figure 1 The light emitting diode further includes a third insulating layer 62, which is located on the side of the first insulating layer 61 away from the second insulating layer 42 and covers the connecting electrode 30. The third insulating layer 62 can be formed by a physical vapor deposition process or a chemical vapor deposition process or other suitable methods. The third insulating layer 62 can be a single-layer structure formed by the same material or a stacked structure formed by stacking different materials. The third insulating layer 62 can be formed of a material substantially the same as the first insulating layer 61, or can be formed of a different material. An opening 621 is provided in the third insulating layer 62, and the opening 621 exposes the surface of the connecting electrode 30.

[0109] In this embodiment, the light emitting diode further includes a pad electrode 71, which is located on a side of the connecting electrode 30 away from the first insulating layer 61, and is electrically connected to the connecting electrode 30 via the opening 621. The pad electrode 71 may be a single-layer structure or a multi-layer structure, and the material of the pad electrode 71 includes one or more materials such as Au, Sn, Ni, Pb, Ag, In, Cr, Ge, Si, Ti, W, and Pt. Optionally, the pad electrode 71 includes a first pad layer 711 and a second pad layer 712, wherein the first pad layer 711 is formed on the first electrode 31 and is located on a side of the first electrode 31 away from the first insulating layer 61, and the second pad layer 712 is formed on the second electrode 32 and is located on a side of the second electrode 32 away from the first insulating layer 61.

[0110] As described above, the light-emitting diode of this embodiment ensures good ohmic contact between the first electrode 31 and the first semiconductor layer 21 by setting a second contact layer 3121 with a smaller thickness, thereby improving the reflectivity of the first electrode 31 and further improving the light-emitting effect of the light-emitting diode. By utilizing the first contact layer 3111 with a larger thickness, it is ensured that the first electrode 31 has good adhesion with the first insulating layer 61, thereby improving the structural stability and working reliability of the light-emitting diode.

[0111] Embodiment 2

[0112] This embodiment provides another light emitting diode, referring to Fig.14 , including an epitaxial stack 20, an insulating layer 60 and a connecting electrode 30. For details of the epitaxial stack 20 and the insulating layer 60 of this embodiment, please refer to the first embodiment.

[0113] In this embodiment, refer to Fig.14a and Fig.14b The connecting electrode 30 is formed on the first insulating layer 61, and includes a first electrode 31 and a second electrode 32. The first electrode is electrically connected to the first semiconductor layer 21 via a fifth through hole 612, and the second electrode is electrically connected to the second semiconductor layer 23 via a fourth through hole 611; wherein the first electrode 31 includes a contact layer 301, and the contact layer 301 includes a first contact portion 3011 formed on the first insulating layer 61 and a second contact portion 3012 formed on the surface of the first semiconductor layer 21 exposed by the slot 241. Optionally, the thickness of the second contact portion 3012 is less than that of the first contact portion 3011.

[0114] The thickness and material of the first contact portion 3011 and other parameters refer to the first contact layer in the first embodiment, and the thickness and material of the second contact portion 3012 and other parameters refer to the second contact layer in the first embodiment, that is, the contact layer 301 of this embodiment corresponds to the first contact layer 3111 and the second contact layer 3112 in the first embodiment. Compared with the prior art, the relatively thin second contact portion 3012 can reduce the absorption of light, effectively improve the reflectivity of the first electrode, and enhance the light extraction efficiency of the light emitting diode. The relatively thick first contact portion 3011 can ensure good adhesion between the first electrode 31 and the first insulating layer 61, and improve the structural stability and working reliability of the light emitting diode.

[0115] In an optional embodiment, in the top view of the light emitting diode, the area of ​​the first contact portion 3011 is greater than the area of ​​the second contact portion 3012; optionally, in the top view of the light emitting diode, the ratio between the area of ​​the first contact portion 3011 and the area of ​​the first electrode 31 is greater than 80%. The first contact portion 3011 contacts the first insulating layer 61, and by making the first contact portion 3011 have a larger contact area, it is possible to ensure that the first electrode 31 has a good adhesion effect with the first insulating layer 61, thereby improving the structural stability of the light emitting diode.

[0116] Please refer to the first embodiment for parameters such as the material and preparation method of the connection electrode 30. Optionally, the first electrode 31 in this embodiment is a laminated structure, and the contact layer 301 is the first layer of the laminated structure. Further, the first electrode 31 also includes a metal reflective layer 302 formed on the contact layer 301. The metal reflective layer can be, for example, a metal silver layer. The first electrode 31 can also include other material layers formed on the metal reflective layer 302. By providing the metal reflective layer 302, which cooperates with the contact layer 301 to form a reflective structure, the reflectivity of the first electrode 31 is effectively improved, and the light extraction efficiency of the light-emitting diode is enhanced.

[0117] In this embodiment, the second electrode 32 may adopt the same stacked structure as the first electrode 31 of this embodiment, or may adopt the structure of the second electrode 32 described in Embodiment 1, or other suitable structures; optionally, the light-emitting diode may also include the transparent conductive layer 41, the second insulating layer 42, the metal layer 51, the pad electrode 71 and the third insulating layer 62 described in Embodiment 1.

[0118] Embodiment 3

[0119] This embodiment provides another light emitting diode, referring to Fig.15, the similarities with the first embodiment are not repeated, the difference is that in the light emitting diode of this embodiment, a plurality of third through holes 411 are provided in the transparent conductive layer 41, the third through holes 411 penetrate the transparent conductive layer 41 in the vertical direction to expose the second semiconductor layer 23, and the third through holes 411 and the first through holes 421 are arranged in a staggered manner, and the second insulating layer 42 is filled in the third through holes 411 to cover the exposed surface of the second semiconductor layer 23. By providing the third through holes 411, the absorption of light by the transparent conductive layer 41 can be reduced, the light extraction efficiency of the light emitting diode can be improved, and the light emitting effect of the light emitting diode can be enhanced.

[0120] In an optional embodiment, the third through hole 411 includes a plurality of holes, and the transparent conductive layer 41 is patterned by photolithography and etching to obtain a plurality of third through holes 411 uniformly distributed in an array. In the top view of the light-emitting diode, the shape of the third through hole 411 can be circular, elliptical, polygonal or other acceptable shapes, the shape of the first through hole 421 can be the same as or different from the shape of the third through hole 411, and the third through hole 411 and the first through hole 421 are staggered.

[0121] Embodiment 4

[0122] This embodiment provides another light emitting diode, referring to Fig.16 , the similarities with the first embodiment are not repeated here, the difference is that the light emitting diode of this embodiment further includes a metal barrier layer 52, the metal barrier layer 52 is located on the side of the second insulating layer 42 away from the transparent conductive layer 41, and covers the metal layer 51, the fourth through hole 611 of the first insulating layer 61 exposes the metal barrier layer 52, and the second electrode 32 contacts the metal barrier layer 52 via the fourth through hole 611.

[0123] In an optional embodiment, the material of the metal barrier layer 52 includes a metal material, such as Ti, Pt, W, In, Sn, Al, Ni, Cr, Au and other metal materials or alloy materials formed by the above metals. The metal barrier layer 52 can be a single-layer structure or a stacked structure formed by stacking at least two materials.

[0124] In an optional embodiment, the metal layer 51 is formed on the second insulating layer 42, and the metal barrier layer 52 covers at least part of the surface of the metal layer 51, for example, the metal barrier layer 52 covers part of the surface of the metal layer 51 away from the second insulating layer 42 or the entire surface, or also covers the side of the metal layer 51 to completely cover the exposed surface of the metal layer 51. By providing the metal barrier layer 52 to cover the metal layer 51, it is possible to prevent the components of the metal layer 51 from being diffused by heat or electricity, and to prevent the surface of the metal layer 51 from being oxidized, thereby reducing the reflectivity of the metal layer 51.

[0125] Embodiment 5

[0126] This embodiment provides another light emitting diode, referring to Fig.17 , the similarities with the first embodiment are not repeated here, the difference is that, in the light-emitting diode of this embodiment, the first insulating layer 61 includes an insulating barrier layer 601, the insulating barrier layer 601 covers the metal layer 51, and a sixth through hole 6011 is provided in the insulating barrier layer 601, the second electrode 32 is electrically connected to the metal layer 51 via the first through hole 421 and the sixth through hole 6011, and optionally, in the top view of the light-emitting diode, the first through hole 421 and the sixth through hole 6011 at least partially overlap, so that the second electrode 32 is electrically connected to the metal layer 51 via the first through hole 421 and the sixth through hole 6011.

[0127] In an optional embodiment, the material of the insulating barrier layer 601 includes an insulating material that can have a blocking effect on the metal layer 51, for example, the material of the insulating barrier layer 601 includes aluminum oxide, etc., and the insulating barrier layer 601 can be formed by methods such as atomic deposition process. The first insulating layer 61 also includes an insulating filling layer, which is formed on the second insulating layer 42 and covers the insulating barrier layer 601. Optionally, the material of the insulating filling layer can be substantially the same as the material of the insulating barrier layer 601, or it can be different. For example, the material of the insulating filling layer includes silicon oxide. By providing the insulating barrier layer 601 to cover the metal layer 51, it is possible to block the components of the metal layer 51 from being diffused by heat or electricity, and to prevent the surface oxidation of the metal layer 51 from causing the reflectivity of the metal layer 51 to be reduced. A sixth through hole 6011 partially overlapping the first through hole 421 is opened in the second barrier to ensure that the second electrode 32 is electrically connected to the metal layer 51.

[0128] Embodiment 6

[0129] This embodiment provides a light emitting device 80, referring to Fig.18 The light emitting device 80 includes a circuit substrate 82 and a plurality of light emitting elements 81 connected to the circuit substrate 82. The light emitting element 81 includes any light emitting diode in the aforementioned embodiments and combinations thereof. The light emitting device 80 may be an LED backlight device, an RGB display device, or other light emitting devices 80. Since the light emitting device 80 includes the light emitting diode in the aforementioned embodiments, it also has the beneficial effects of the aforementioned embodiments.

[0130] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify, change or combine the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A light emitting diode, characterized in that: include: An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer; an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole; A connecting electrode is formed on the insulating layer, comprising a first electrode and a second electrode, the first electrode being electrically connected to the first electrode layer via the fifth through hole, the second electrode being electrically connected to the second semiconductor layer via the fourth through hole, the first electrode comprising a first electrode layer formed on the insulating layer and a second electrode layer partially formed on the first electrode layer, the second electrode layer also comprising a portion of the surface of the first semiconductor layer exposed by the slot through the fifth through hole, the first electrode layer comprising a first contact layer in contact with the insulating layer, and the second electrode layer comprising a second contact layer in contact with the surface of the first semiconductor layer; wherein the thickness of the second contact layer is less than the thickness of the first contact layer.

2. The light emitting diode according to claim 1, characterized in that: The first contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the first contact layer is The second contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the second contact layer is 3. The light emitting diode according to claim 1, characterized in that: The first electrode layer further includes a first metal reflective layer formed on the first contact layer, and the second electrode layer further includes a second metal reflective layer formed on the second contact layer. The thickness of the first metal reflective layer is equal to the thickness of the second metal reflective layer.

4. The light emitting diode according to claim 1 or 3, characterized in that: The reflectivity of the first electrode layer is lower than the reflectivity of the second electrode layer.

5. The light emitting diode according to claim 1, characterized in that: The second electrode layer has a first portion in contact with the first electrode layer and a second portion in contact with the first semiconductor layer. In a top view of the light-emitting diode along the thickness direction of the epitaxial stack, an area of ​​the first portion is larger than an area of ​​the second portion.

6. The light emitting diode according to claim 1, characterized in that: A plurality of recessed portions are also provided on the periphery of the epitaxial stack, and the recessed portions penetrate the second semiconductor layer, the active layer and part of the first semiconductor layer along the thickness direction of the epitaxial stack to expose part of the surface of the first semiconductor layer, and the second electrode layer contacts the surface of the first semiconductor layer exposed by the recessed portions via the fifth through hole.

7. The light emitting diode according to claim 6, characterized in that: Also included is a substrate, the epitaxial stack is formed on the substrate; In the top view of the light-emitting diode, the distance between the first electrode layer and the edge of the substrate is greater than the distance between the second electrode layer and the edge of the substrate, the distance between the edge of the first electrode layer and the edge of the second electrode layer is the electrode layer edge spacing, and the value of the electrode layer edge spacing in the area where the recess is located is greater than the value of the electrode layer edge spacing in other areas of the light-emitting diode.

8. The light emitting diode according to claim 1, characterized in that: The second electrode includes a third electrode layer and a fourth electrode layer, the third electrode layer includes a third contact layer formed on the insulating layer, the fourth electrode layer includes a fourth contact layer formed on the third electrode layer, and the thickness of the third contact layer is greater than that of the fourth contact layer.

9. The light emitting diode according to claim 8, characterized in that: A first gap is provided between the first electrode layer and the third electrode layer, a second gap is provided between the second electrode layer and the fourth electrode layer, and a width of the first gap is smaller than a width of the second gap.

10. The light emitting diode according to claim 8, characterized in that: The third electrode layer further includes a third metal reflective layer formed on the third contact layer, and the fourth electrode layer further includes a fourth metal reflective layer formed on the fourth contact layer. The thickness of the third metal reflective layer is equal to that of the fourth metal reflective layer.

11. The light emitting diode according to claim 8, characterized in that: The third contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the third contact layer is The fourth contact layer is a metal chromium layer, a metal nickel layer or a metal titanium layer, and the thickness of the fourth contact layer is 12. A light emitting diode, characterized in that: include: An epitaxial stack, comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the epitaxial stack has a slot, and the slot penetrates the second semiconductor layer, the active layer, and a portion of the first semiconductor layer to expose a portion of the surface of the first semiconductor layer; an insulating layer formed on the epitaxial stack, wherein the insulating layer is provided with a fourth through hole and a fifth through hole; A connecting electrode is formed on the insulating layer, including a first electrode and a second electrode, the first electrode is electrically connected to the first semiconductor layer via the fifth through hole, and the second electrode is electrically connected to the second semiconductor layer via the fourth through hole, the first electrode includes a contact layer, the contact layer includes a first contact portion formed on the insulating layer and a second contact portion formed on the surface of the first semiconductor layer exposed by the slot, and the thickness of the second contact portion is less than the thickness of the first contact portion.

13. The light emitting diode according to claim 12, characterized in that: In a top view of the light emitting diode, an area of ​​the first contact portion is greater than an area of ​​the second contact portion.

14. The light emitting diode according to claim 1 or 12, characterized in that: The light emitting diode further comprises a transparent conductive layer and a metal layer, and the insulating layer comprises a first insulating layer and a second insulating layer: The transparent conductive layer is formed on the epitaxial stack; The second insulating layer is formed on the epitaxial stack and covers the transparent conductive layer. The second insulating layer has a first through hole and a second through hole. The first through hole exposes the transparent conductive layer, and the second through hole exposes the surface of the first semiconductor layer exposed by the slot. The metal layer is formed on the second insulating layer and contacts the transparent conductive layer via the first through hole; The first insulating layer is formed on the metal layer and covers the second insulating layer.

15. The light emitting diode according to claim 14, characterized in that: A plurality of third through holes spaced apart from each other are arranged in the transparent conductive layer, the third through holes expose the second semiconductor layer and are arranged in a staggered manner with the first through holes.

16. The light emitting diode according to claim 14, characterized in that: The light emitting diode further includes a metal barrier layer formed on the second insulating layer and covering the metal layer. The fourth through hole exposes the metal barrier layer. The second electrode contacts the metal barrier layer via the fourth through hole.

17. The light emitting diode according to claim 14, characterized in that: The second insulating layer includes an insulating barrier layer covering the metal layer, a sixth through hole is provided in the insulating barrier layer, and the second electrode contacts the metal layer via the fourth through hole and the sixth through hole.

18. The light emitting diode according to claim 14, characterized in that: Also includes: a third insulating layer, located on a side of the first insulating layer away from the second insulating layer, covering the connecting electrode, and having an opening exposing the connecting electrode; The pad electrode is located at a side of the connection electrode away from the first insulating layer and is electrically connected to the connection electrode via the opening.

19. A light emitting device, characterized in that: The invention comprises a circuit substrate and a plurality of light emitting elements connected to the circuit substrate, wherein the light emitting elements comprise the light emitting diodes according to any one of claims 1 to 18.

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