阅读说明：本技术 发光二极管及发光装置 (Light emitting diode and light emitting device ) 是由 蔡家豪 汪琴 周立 于 2021-08-30 设计创作，主要内容包括：本发明属于半导体技术领域,尤其涉及发光二极管及发光装置,本发明提供的发光二极管,其在第一电极的下方设置第一电流阻挡结构,并且第一电流阻挡结构的边缘与第一电极的分支部边缘的距离随着远离第一电极的焊盘的方向减小或者增大,从而促进电流的扩展,获得高亮度、发光均匀的发光二极管。(The invention belongs to the technical field of semiconductors, and particularly relates to a light-emitting diode and a light-emitting device.)

1. The light emitting diode at least comprises a first semiconductor layer, a second semiconductor layer and an active layer arranged between the first semiconductor layer and the second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer are different in conduction type, and a first electrode and a second electrode are respectively arranged on the first semiconductor layer and the second semiconductor layer, the first electrode comprises a first welding part and a first branch part, and the light emitting diode is characterized in that a first current blocking structure is arranged between the first electrode and the first semiconductor layer, and the distance between the edge of the first current blocking structure and the edge of the first branch part is increased or decreased along with the direction away from the first pad part.

2. The light-emitting diode according to claim 1, wherein the width of the first branch portion is constant in a direction away from the first pad portion, and the width of the first current blocking structure is gradually decreased or increased.

3. The light-emitting diode according to claim 1, wherein the width of the first branch portion gradually increases or decreases as the width of the first current blocking structure is constant in a direction away from the first pad portion.

4. The led of claim 1, wherein the first current blocking structure comprises a first blocking body under the first pad portion, and a first blocking branch under the first branch portion.

5. The LED of claim 4 wherein the first blocking leg is connected or not connected to the first blocking body.

6. The LED of claim 4, wherein the first blocking branch is a continuous integral strip structure or comprises a plurality of spaced first blocky blocking structures.

7. The light-emitting diode according to claim 6, wherein the pitch of the first blocking structures is constant or decreases or increases in a direction away from the first pad portion.

8. The light-emitting diode according to claim 6, wherein the length of the first blocking structure is constant or decreases or increases in a direction away from the first pad portion.

9. The LED of claim 4, wherein the second electrode comprises a second pad and a second branch portion, and further comprising a second barrier structure between the second semiconductor layer and the second electrode, the second barrier structure comprising a second barrier body under the second pad and a second barrier branch under the second branch portion.

10. The light-emitting diode according to claim 9, wherein a straight-line distance between an edge of the second blocking branch and an edge of the second branch portion is constant or increases or decreases in a direction away from the second pad portion.

11. The light-emitting diode according to claim 10, wherein the width of the second branch portion is constant in a direction away from the second pad portion, and the width of the second blocking branch is gradually decreased or increased.

12. The light-emitting diode according to claim 10, wherein the width of the second blocking branch is constant in a direction away from the second pad portion, and the width of the second branch portion is gradually increased or decreased.

13. The led of claim 9, wherein the second blocking branch is a continuous integral stripe structure or comprises a plurality of spaced second block-shaped blocking structures.

14. The led of claim 13, wherein the second blocking branch is connected or not connected to the second blocking body.

15. The led of claim 9, wherein the second barrier body is in the form of a unitary or discrete ring, block.

16. The led of claim 9, wherein the second blocking branch has an enlarged end.

17. The led of claim 9, wherein the first blocking branch end is located between the first blocking body and the second blocking body, and the first blocking branch end is at the same or different linear distance from the first blocking body and the second blocking body.

18. The led of claim 9, wherein the shortest straight distance between the first blocking branch and the second blocking branch decreases in a direction away from the first pad.

19. The led of claim 1, wherein a first transparent conductive layer is further disposed between the first electrode and the first current blocking structure, and the first transparent conductive layer covers the first current blocking structure and a surface of the first semiconductor layer.

20. The led of claim 9, further comprising a second transparent conductive layer between the second electrode and the second current blocking structure, the second transparent conductive layer covering the second current blocking structure and a surface of the second semiconductor layer.

21. The light-emitting diode of claim 1, further comprising a substrate, wherein the first and second electrodes are on the same side of the substrate.

22. The led of claim 21, wherein the surface of the substrate has recesses and protrusions, the protrusions comprising a first region proximate the surface of the substrate and a second region on the first region, the second region having a refractive index less than the refractive index of the first region.

23. A light-emitting device comprising the light-emitting diode according to any one of claims 1 to 22.

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to a light emitting diode with a current blocking structure and a light emitting device.

Background

Because the Light Emitting Diode (LED) structure has the advantages of low power consumption, environmental protection, long service life, and fast response speed, it has been widely used in the illumination field and the display field.

The conventional nitride light emitting element has a current crowding phenomenon in which a current is not uniformly distributed between a p-type electrode and an n-type electrode but is concentrated in a local region of a light emitting layer adjacent to the n-type electrode. This current crowding phenomenon not only increases the forward voltage of the light emitting diode, but also reduces the light emitting efficiency of the other side of the light emitting layer away from the n-type electrode, which reduces the overall brightness of the light emitting element. Furthermore, in the local region where the current is concentrated, heat is gradually generated and accumulated, thereby generating an overheating phenomenon, which greatly reduces the reliability of the light emitting diode.

Disclosure of Invention

The light emitting diode at least comprises a first semiconductor layer, a second semiconductor layer and an active layer arranged between the first semiconductor layer and the second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer are different in conduction type, and a first electrode and a second electrode are respectively arranged on the first semiconductor layer and the second semiconductor layer, the first electrode comprises a first welding part and a first branch part, and the light emitting diode is characterized in that a first current blocking structure is arranged between the first electrode and the first semiconductor layer, and the distance between the edge of the first current blocking structure and the edge of the first branch part is increased or decreased along with the direction away from the first pad part.

The invention also provides a light-emitting device comprising the light-emitting diode.

The invention provides a light-emitting diode, wherein a first current blocking structure is arranged below a first electrode, and the distance between the edge of the first current blocking structure and the edge of a branch part of the first electrode is reduced or increased along with the direction of a bonding pad far away from the first electrode, so that the current expansion is promoted, and the light-emitting diode with high brightness and uniform light emission is obtained.

The foregoing has outlined rather broadly the features and advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Other technical features and advantages are described below within the scope of the claims that form the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or manufacturing processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

Drawings

A full appreciation of the features and advantages of the invention can be gained by taking the foregoing description in conjunction with the following drawings.

Fig. 1 is a top view of a conventional light emitting diode in the prior art.

Fig. 2 is a top view of a light emitting diode according to a first embodiment of the present invention.

Fig. 3 is a cross-sectional view of the light emitting diode shown in fig. 2 taken along line a-a.

Fig. 4 is a cross-sectional view of the light emitting diode shown in fig. 2 taken along line B-B.

Fig. 5 is a top view of the led of fig. 4 according to a variation.

Fig. 6 is an enlarged view of a partial region P shown in fig. 2.

FIG. 7 is a top view of a second embodiment of the present invention.

FIG. 8 is a graph showing the brightness contrast of the light emitting diode according to the prior art, the first embodiment and the second embodiment.

Detailed Description

Fig. 1 is a top view of a prior art light emitting diode.

The light emitting diode 10 in the related art includes a substrate 11, a semiconductor stack including a first semiconductor layer 12, a light emitting layer 13, and a second semiconductor layer 14, a transparent conductive layer 162, and electrodes 171 and 172, wherein the first electrode 171 is electrically connected to the first semiconductor layer 12, and the second electrode 172 is electrically connected to the second semiconductor layer 14 through the transparent conductive layer 162. The first electrode 171 includes a first pad portion 1711 and a first branch portion 1712, and the second electrode 172 includes a second pad portion 1721 and a second branch portion 1722. In order to facilitate current spreading, a first current blocking structure 151 is formed between the first electrode 171 and the first semiconductor layer 12, and a second current blocking structure 152 is formed between the transparent conductive layer 162 and the second semiconductor layer 14, respectively.

The first current blocking structure 151 includes a first blocking body 1511 and a first blocking branch 1512, the first blocking body 1511 is located below the first pad portion 1711, and the first blocking branch 1512 is located below the first branch portion 1712. The second barrier structure 152 includes a second barrier body 1521 and a second barrier branch 1522, the second barrier body 1521 is located below the second pad portion 1721, and the second barrier branch 1522 is located below the second branch portion 1722.

The first blocking branch 1512 is composed of a plurality of first blocking structures 15121 spaced apart, and the first blocking structure 15121 closest to the first blocking body is not connected to the first blocking body 1511. The distance between the edge of the first barrier body 1511 and the edge of the first branch portion 1712 is constant in a direction away from the first pad portion 1711.

The current blocking structure of the light emitting diode in the prior art has a limited effect on current expansion, and the brightness of the light emitting diode cannot be further improved.

First embodiment

Fig. 2 is a top view of a light emitting diode according to a first embodiment of the present invention, fig. 3 is a cross-sectional view of the light emitting diode shown in fig. 2 taken along a line a-a, fig. 4 is a cross-sectional view of the light emitting diode shown in fig. 2 taken along a line B-B, and fig. 6 is an enlarged view of a partial region P of the light emitting diode shown in fig. 2.

In the top view shown in fig. 2, the light emitting diode 20 comprises at least a substrate 21; a semiconductor stack, which is stacked on a substrate 21 and includes a first semiconductor layer 22, a second semiconductor layer 24, and an active layer 23 disposed between the first semiconductor layer 22 and the second semiconductor layer 24, wherein the first semiconductor layer 22 and the second semiconductor layer 24 have different conductivity types; and a first electrode 271 and a second electrode 272 disposed on the first semiconductor layer 22 and the second semiconductor layer 24, respectively. A first current blocking structure 251 is formed between the first electrode 271 and the first semiconductor layer 22, and a second current blocking structure 252 and a second transparent conductive layer 262 are sequentially formed between the second electrode 272 and the second semiconductor layer 24. The first electrode 271 includes a first pad portion 2711 and a first branch portion 2712, and the second electrode 272 includes a second pad portion 2721 and a second branch portion 2722. The distance between the edge of the first current blocking structure 251 and the edge of the first branch portion 2712 increases in a direction away from the first pad portion 2711.

The first branch portion 2712 extends from the first pad portion 2711 in the direction of the second pad 2721 portion 2721, and the second branch portion 2722 extends from the second pad 2721 portion 2721 in the direction of the first pad portion 2711. The light emitting diode 20 has a rectangular shape having opposite long sides and opposite short sides, and the first pad part 2711 and the second pad 2721 part 2721 are located at opposite short side sides, respectively. Therefore, the first branch portion 2712 and the second branch portion 2722 each extend along a long side of the light emitting diode. In this embodiment, the first electrode 271 and the second electrode 272 are located on the same side of the substrate 21, and in another embodiment, the first electrode 271 and the second electrode 272 may also be located on two opposite sides of the substrate 21.

The substrate 21 is a growth substrate on which a semiconductor stack is grown on the substrate 21, and includes a gallium arsenide (GaAs) substrate for growing gallium indium phosphide (AlGaInP), sapphire (Al)₂O₃) A substrate, a gallium nitride (GaN) substrate, a silicon carbide (SiC) substrate, or an aluminum nitride (AlN) substrate for growing indium gallium nitride (InGaN) or aluminum gallium nitride (AlGaN), or a combination of two or more of the foregoing.

The upper surface of the substrate 21 for epitaxially growing the semiconductor stack may include a patterned structure having a recess and a protrusion, and light emitted from the semiconductor stack may be refracted through the patterned structure of the substrate, thereby improving the brightness of the photoelectric element. In addition, the patterned structure slows down or inhibits dislocation generated by lattice mismatch between the substrate and the semiconductor lamination, thereby improving the epitaxial quality of the semiconductor lamination. The protrusion may include a first region near the surface of the substrate 21 and a second region on the first region, and the refractive index of the second region may be smaller than that of the first region. For example, the substrate 21 is a sapphire substrate 21, the first region is made of sapphire, and the second region is made of silicon dioxide. The light output of the substrate 21 can be further improved by the protrusions made of materials with different refractive indexes.

On the patterned substrate 21, a semiconductor stack may be formed by Metal Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), or ion plating, such as sputtering or evaporation. The semiconductor stack includes a first semiconductor layer 22, an active layer 23, and a second semiconductor layer 24 sequentially formed on a surface of a substrate 21 having recesses and protrusions. The first semiconductor layer 22 and the second semiconductor layer 24 have different conductivity types, electric properties, polarities, or doping elements for supplying electrons or holes. For example, the first semiconductor layer 22 is an n-type semiconductor, and the second semiconductor layer 24 is a p-type semiconductor. n-type impurities such as Si, p-type impurities such as Mg, and the impurity species are not limited thereto. The active layer 23 is formed between the first semiconductor layer 22 and the second semiconductor layer 24. Under current driving, electrons and holes combine in the active layer 23, converting electric energy into light energy to emit light.

The wavelength of light emitted by the light emitting diode or the semiconductor stack is tuned by changing the physical properties and chemical composition of one or more layers of the semiconductor stack. The material of the semiconductor laminated layer comprises III-V semiconductor materials of AlxInyGa (1-x-y) N or AlxInyGa (1-x-y) P, wherein x is more than or equal to 0, and y is less than or equal to 1; (x + y) is less than or equal to 1. Depending on the material of the active layer 23, red light with a wavelength between 610nm and 650nm or yellow light with a wavelength between 550nm and 570nm can be emitted when the material of the semiconductor stack is of the AlInGaP series. When the material of the semiconductor stack is of the InGaN series, blue or deep blue light with a wavelength between 400nm and 490nm, or green light with a wavelength between 490nm and 550nm can be emitted. When the material of the semiconductor stack is of the AlGaN series, UV light having a wavelength between 400nm and 250nm can be emitted.

The active layer 23 may be a Single Heterostructure (SH), a Double Heterostructure (DH), a double-side double heterostructure (DDH), or a Multiple Quantum Well (MQW). The material of the active layer 23 may be an i-type, p-type or n-type semiconductor. The active layer 23 is formed by alternately stacking well layers and barrier layers having different energy bands, wherein the barrier layers have higher energy levels than the well layers, so that electrons and holes are combined in the well layers to emit light. The well layer is typically a layer of In-containing material, such as InGaN; the barrier layer can be one or the combination of at least two of GaN, AlGaN, AlN, AlInGaN and AlInN. The barrier layer closest to the second semiconductor layer 24 may have a higher energy level than the barrier layers of the other layers, for example, the barrier layer is AlN, which may block electrons overflowing from the inside of the active layer 23.

In addition, a buffer layer (not shown) may be formed on the upper surface of the substrate 21 before the semiconductor stack is formed. The buffer layer can reduce the lattice mismatch and suppress dislocation, thereby improving epitaxial quality. The material of the buffer layer comprises GaN, AlGaN, AlN or a combination of at least two, and the thickness distribution of the buffer layer is uniform or nonuniform.

Referring to fig. 3, after the semiconductor layer is fabricated, the second transparent conductive layer 262 is removed to the semiconductor layer of the first semiconductor layer 22 by etching until the upper surface of the first semiconductor layer 22 is exposed, and a first electrode 271 is formed on the first semiconductor layer 22, and a second electrode 272 is formed on the second semiconductor layer 24, the first electrode 271 and the second electrode 272 being electrically connected to the first semiconductor layer 22 and the second semiconductor layer 24, respectively, such that the first electrode 271 and the second electrode 272 are located on the same side of the substrate 21. The material of the first electrode 271 and the second electrode 272 is selected from a metal such as gold (Au), silver (Ag), copper (Cu), chromium (Cr), aluminum (Al), platinum (Pt), nickel (Ni), titanium (Ti), tin (Sn), rhodium (Rh), an alloy or a laminate of the above materials.

The first electrode 271 includes a first pad portion 2711 and a first branch portion 2712, and the first current blocking structure 251 is formed between the first electrode 271 and the first semiconductor layer 22, respectively. Accordingly, the first current blocking structure 251 includes a first blocking body 2511 under the first pad portion 2711, and a first blocking branch 2512 under the first branch portion 2712. The first blocking branch 2512 is a unitary strip structure or includes a plurality of first blocking structures 25121 spaced apart. In this embodiment, the first blocking structure 251 is formed by a plurality of first blocking structures 25121 arranged at intervals, a hole 2513 is formed between adjacent first blocking structures 25121, the bottom of the hole 2513 exposes the first semiconductor layer 22, as shown in fig. 4, the first electrode 271 above the hole 2513 extends to the bottom of the hole 2513 and is in direct contact with the first semiconductor layer 22 for conducting electricity.

Referring to fig. 2, in the present embodiment, as the width of the first branch portion 2712 is constant in a direction away from the first pad portion 2711, the distance d1 between the edge of the first blocking branch 2512 and the edge of the first branch portion 2712 increases (as shown in fig. 6), and the minimum width of the first blocking branch 2512 is greater than the width of the first branch portion 2712. At this time, the width w1 of the first blocking branch 2512 is gradually reduced as it goes away from the first pad part 2711. The first blocking branch 2512 closest to the first pad portion 2711 is widest, and the width of the end of the first blocking branch 2512 is smallest.

The second electrode 272 is on the second semiconductor layer 24, and the second electrode 272 includes a second pad portion 2721 and a second branch portion 2722. Accordingly, the second barrier structure 252 is formed between the second electrode 272 and the second semiconductor layer 24, and the second transparent conductive layer 262 is formed between the second barrier structure 252 and the second electrode 272, and the second barrier structure 252 and the second transparent conductive layer 262 may promote relatively uniform spreading of the current injected into the semiconductor layer by the second electrode 272. Corresponding to the second pad 2721 portion 2721 and the second branch portion 2722, respectively, the second blocking structure 252 includes a second blocking body 25221 located below the second pad 2721, and a second blocking branch 2522 located below the second branch portion 2722. The second blocking body 2521 blocks the current of the second pad portion 2721 from concentrating into a semiconductor layer, which may be in a whole or discrete ring shape, a block shape. A straight distance between an edge of the second blocking branch 2522 and an edge of the second branch portion 2722 is constant or increases or decreases in a direction away from the second pad portion 2721, and a width of the second blocking branch 2522 is greater than a width of the second branch portion 2722, facilitating current spreading of the second branch portion 2722. In this embodiment, as the width of the second blocking branch 2522 is constant in a direction away from the second pad portion 2721, the width of the second branch portion 2722 decreases, and thus a linear distance between an edge of the second blocking branch 2522 and an edge of the second branch portion 2722 increases in a direction away from the second pad portion 2721.

The first blocking branch 2512 is a discontinuous block structure (composed of a plurality of first blocking structures 25121), the first blocking structure 25121 closest to the first blocking body 2511 is connected or not connected with the first blocking body 2511, in another embodiment, the first blocking branch 2512 is a continuous integral strip structure, and the first blocking branch 2512 may be connected or not connected with the first blocking body 2511; preferably, in this embodiment, the first blocking branch 2512 is a discontinuous block structure, and the first block structure 25121 closest to the first blocking body 2511 is not connected to the blocking body 2511, and has a hole 2513 therebetween, and the first electrode 271 extends downward into the hole 2513 and is electrically connected to the first semiconductor layer 22.

The second blocking branch 2522 is a continuous integral strip structure, or comprises a plurality of second blocking structures distributed discontinuously at intervals, and the second blocking branch 2522 is connected or not connected to the second blocking body 2521. Preferably, the second blocking branch 2522 in this embodiment is a continuous integral strip structure, and the end of the second blocking branch 2522 is enlarged. The enlarged end may promote a more uniform spreading of the current at the end of the second blocking branch 2522 due to the greater current density at the end of the second blocking branch 2522.

The spacing d2 (shown in FIG. 6) of adjacent first blocky stop structures 25121 may be the same or different. In the present embodiment, the pitches d2 of the adjacent first bulk barrier structures 25121 are the same, and the widths of the first branch portions 2712 are not changed, the width w1 of the first current barrier structure 251 is decreased in a direction away from the first pad portion 2711, so that the distance d1 between the edge of the first current barrier structure 251 and the edge of the first branch portion 2712 is increased in a direction away from the first pad portion 2711. Further, the width w1 of the first blocking structure 25121 decreases in a direction away from the first pad portion 2711.

Current is injected into the semiconductor stack from the second electrode 272 and flows through the semiconductor stack back to the first electrode 271, with the current density at the end of the second branch portion 2722 being greatest. Therefore, in the region of the first semiconductor layer 22, the current density is higher in the region close to the second branch portion 2722, and is lower in the region far from the second branch portion 2722. Therefore, the first blocking branch 2512 near the end of the second branch portion 2722 is wider to better promote current spreading, and the first blocking branch 2512 far from the end of the second branch portion 2722 is narrower to reduce light loss caused by light absorption, thereby improving light extraction efficiency of the led.

The width of the first branch portion 2712 is smaller than the width of the first blocking branch 2512, which can facilitate the spread of current in the semiconductor stacked layer. In another embodiment, the spacing d2 of the first blocking structure 25121 decreases in a direction away from the first pad portion 2711. In another embodiment, the spacing d2 of the first blocking structure 25121 increases with distance from the first pad portion 2711.

The length L (shown in fig. 6) of the first block stop 25121 may be the same or different. In this embodiment, the length L of the first blocking structure 25121 is the same as the direction away from the first pad portion 2711, and in other embodiments the length L of the first blocking structure 25121 decreases as the direction away from the first pad portion 2711. The length L of the first blocking structure 25121 increases in a direction away from the first pad part 2711 in other embodiments.

In one embodiment, the lateral surfaces of the first blocking structures 25121 are perpendicular to the upper surface of the first semiconductor layer 22, and in another embodiment, the lateral surfaces are inclined with respect to the upper surface of the first semiconductor layer 22, and the inclined lateral surfaces facilitate light extraction. In an embodiment, the first blocking feature 25121 has a radiused angle or radiused edge, and the first blocking feature 25121 having a radiused angle or radiused edge facilitates light extraction.

In a top view of the light emitting diode, the first blocking branch 2512 ends between the first blocking body 2511 and the second blocking body 2521, and the linear distances of the first blocking branch 2512 ends are the same as or different from those of the first blocking body 2511 and the second blocking body 2521. In this embodiment, the linear distance between the end of the first blocking branch 2512 and the first blocking body 2511 and the linear distance between the end of the second blocking body 2521 are substantially the same, which can promote current spreading and make the current density more uniformly distributed on the surfaces of the first semiconductor layer 22 and the second semiconductor layer 24.

A straight distance d3 (shown in fig. 2) of the first blocking branch 2512 and the second blocking branch 2522 decreases in a direction away from the first pad portion 2711. The straight distance d3 between the first blocking branch 2512 and the second blocking branch 2522 is the largest near the first pad portion 2711, and the straight distance d3 between the end of the first blocking branch 2512 and the second blocking branch 2522 is the smallest far from the first pad portion 2711.

The first blocking branch 2512 is located at an edge of one side of the first semiconductor layer 22, and the second blocking branch 2522 is inclined towards an edge of the other side opposite to the first semiconductor layer 22 as the first blocking branch is away from the second pad 2721 part 2721, that is, a linear distance d4 (shown in fig. 2) between the second blocking branch 2522 and an edge of a side of the first semiconductor layer 22 decreases as the second blocking branch is away from the second pad 2721 part 2721, and a linear distance d4 between an end of the second blocking branch 2522 and the edge of the side is the smallest. Since the first branch portion 2712 and the second branch portion 2722 are respectively located above the first blocking branch 2512 and the second blocking branch 2522, the first branch portion 2712 and the second branch portion 2722 also conform to the aforementioned design rule. Since the distance between the first branch portion 2712 and the second branch portion 2722 is large, current can be promoted to be uniformly distributed over the entire surface of the semiconductor layer, and a light emitting diode with high luminance and high uniformity can be realized.

The material of the first current blocking structure 251 and the second current blocking structure 252 includes a transparent insulating material such as silicon oxide, silicon nitride, silicon oxynitride, titanium oxide, or aluminum oxide. The first current blocking structure 251 and the second current blocking structure 252 may be a single layer or an alternating multilayer structure, such as a Distributed Bragg Reflector (DBR). The thickness of the first current blocking structure 251 and the second current blocking structure 252 may range from 700 to 5000 a.

The second transparent conductive layer 262 is disposed on the light emitting side of the led, so that it is more suitable to select a conductive material having a transparent property. More specifically, the transparent conductive layer 262 may include a thin metal film or a metal oxide structure. The material of the thin metal film includes gold or nickel. The material of the metal oxide structure includes at least one element selected from metals such as zinc, indium, and tin, such as ZnO, InO, SnO, ITO (indium tin oxide), IZO (indium zinc oxide), and GZO (gallium-zinc oxide). The transparent conductive layer 262 has high optical transmittance, for example, 60%, 70%, 75%, 80% or more, to light emitted from the active layer 23, and has high conductivity. The area covered by the second transparent conductive layer 262 on the surface of the second semiconductor layer 24 is smaller than the area of the upper surface of the second semiconductor layer 24, and the area of the second transparent conductive layer 262 accounts for more than 80% of the area of the upper surface of the second semiconductor layer 24. In an embodiment, the coverage area of the second transparent conductive layer 262 is smaller in the area with smaller current density on the upper surface of the second semiconductor layer 24, and the second transparent conductive layer 262 is fully covered in the area with larger current density, so that the current utilization efficiency is improved.

Fig. 5 is a top view of a variation of the led shown in fig. 4.

Referring to fig. 5, a first transparent conductive layer 261 may be further disposed between the first electrode 271 and the first barrier structure 251, and the first transparent conductive layer 261 covers the surfaces of the first barrier structure 251 and the first semiconductor layer 22. In one embodiment, the first transparent conductive layer 261 on the holes 2513 between adjacent first blocking structures 25121 extends downward and contacts the first semiconductor layer 22, covering the first transparent conductive layer 261 on both the bottom and sides of the holes 2513. The first electrode 271 is located on the first transparent conductive layer 261, and is electrically connected to the first semiconductor layer 22 through the first transparent conductive layer 261. The first branch portion 2712 is located on the first transparent conductive layer 261, extends downward at the position of the hole 2513 and contacts the first transparent conductive layer 261 at the bottom of the hole 2513.

In another embodiment, the first transparent conductive layer 261 has an opening (not shown) above the hole 2513 to expose the first semiconductor layer 22 at the bottom of the hole 2513, and the first electrode 271 extends downward into the hole 2513 and is in direct contact with the first semiconductor layer 22 for conducting electricity. The plurality of first blocking structures 25121 block the current expanded by the first branch portion 2712 from flowing downward, and the current flows downward into the first semiconductor layer 22 through the hole 2513 between two adjacent first blocking structures 25121. The spaced apart first blocky barrier structures 25121 may promote a more uniform entry of current spreading by the first branch portion 2712 into the first semiconductor layer 22.

Since the first transparent conductive layer 261 is disposed on the light emitting side of the light emitting diode, it is more appropriate to select a conductive material having a transparent property. More specifically, the transparent conductive layer 261 may include a thin metal film or a metal oxide structure. The material of the thin metal film includes gold or nickel. The material of the metal oxide structure includes at least one element selected from metals such as zinc, indium, and tin, such as ZnO, InO, SnO, ITO (indium tin oxide), IZO (indium zinc oxide), and GZO (gallium-zinc oxide). The transparent conductive layer 261 has high optical transmittance, for example, 60%, 70%, 75%, 80% or more, for light emitted from the active layer 23, and has high conductivity.

In another embodiment, the width of the first blocking branch 2512 is constant as it goes away from the first pad part 2711, and the width of the first branch part 2712 is gradually decreased such that the distance between the edge of the first blocking branch 2512 and the edge of the first branch part 2712 is gradually increased. The width of first blocking branch 2512 is greater than the maximum width of first branch portion 2712.

Second embodiment

Referring to fig. 7, in the present embodiment, the light emitting diode 30 includes at least a substrate 31; a semiconductor stack laminated on a substrate 31, including a first semiconductor layer 32, a second semiconductor layer 34, and an active layer 33 disposed between the first semiconductor layer 32 and the second semiconductor layer 34, wherein the first semiconductor layer 32 and the second semiconductor layer 34 have different conductivity types; and a first electrode 371 and a second electrode 372 disposed on the first semiconductor layer 32 and the second semiconductor layer 34, respectively. A first current blocking structure 351 is formed between the first electrode 371 and the first semiconductor layer 32, and a second current blocking structure 352 and a second transparent conductive layer 362 are sequentially formed between the second electrode 372 and the second semiconductor layer 34. The first electrode 371 includes a first pad portion 3711 and a first branch portion 3712, and the second electrode 372 includes a second pad portion 3721 and a second branch portion 3721 and 3722. The distance between the edge of the first current blocking structure 351 and the edge of the first branch portion 3712 increases with the direction away from the first pad portion 3711.

In an embodiment, as the width of the first branch portion 3712 is constant in a direction away from the first pad portion 3711, the distance of the edge of the first blocking branch 3512 from the edge of the first branch portion 3712 is reduced, and the minimum width of the first blocking branch 3512 is greater than the width of the first branch portion 3712. At this time, the width of the first blocking branch 3512 gradually increases as it goes away from the first pad portion 3711. The first blocking branch 3512 closest to the first pad portion 3711 is narrowest, and the end of the first blocking branch 3512 is widest.

In another embodiment, the width of the first branch portion 3712 is constant as it goes away from the first pad portion 3711, and the width of the first branch portion 3712 is gradually increased such that the distance between the edge of the first branch portion 3512 and the edge of the first branch portion 3712 is gradually decreased. The width of the first blocking branch 3512 is greater than the maximum width of the first branch portion 3712.

Referring to fig. 8, through a comparative experiment on the light emitting diodes in the prior art, the first embodiment and the fourth embodiment, it is found that the brightness is improved in the first embodiment and the fourth embodiment compared with the light emitting diode in the prior art, and the brightness is improved more in the first embodiment, 0.13% in the first embodiment and 0.51% in the fourth embodiment.

The invention also provides a light-emitting device, which comprises any one of the light-emitting diodes and has the characteristic of higher brightness.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify and change the above-described embodiments without departing from the technical principles and spirit of the present invention. The scope of the invention is therefore intended to be indicated by the appended claims.