Light emitting diode and light emitting device

Abstract

The invention relates to the technical field of semiconductor manufacturing, in particular to a light-emitting diode and a light-emitting device.The light-emitting diode comprises a semiconductor laminated layer and a transparent conducting layer, the semiconductor laminated layer comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are sequentially laminated, and the semiconductor laminated layer is provided with a first table top and a second table top; the first mesa is exposed out of the first semiconductor layer, the second mesa is exposed out of the second semiconductor layer, the second mesa is higher than the first mesa, the transparent conducting layer is arranged on the second semiconductor layer, the transparent conducting layer and the second semiconductor layer are the same in morphology in a top view, and the area of the transparent conducting layer at least accounts for 95% of the area of the second semiconductor layer. Through the arrangement, the light emitting uniformity of the light emitting diode can be improved, and the performance of the device is improved.

Description

Technical Field

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

[0002] In recent years, light-emitting diodes (LEDs) have been widely used in general and commercial lighting applications. As a light source, LEDs offer many advantages, including lower energy consumption, longer lifespan, smaller size, and faster switching speed. Therefore, traditional lighting sources, such as incandescent lamps, are gradually being replaced by LED light sources. In an LED, when electrons and holes recombine across the semiconductor band gap, the recombination energy is emitted as photons, producing light. This recombination mechanism is known as radiative recombination.

[0003] Currently, for flip-chip Micro LEDs, a transparent conductive layer is typically deposited on the P-type layer during the chip fabrication process to serve as a current spreader, forming an ohmic contact. The design of this current spreader significantly impacts the device's luminous uniformity and luminous area. For example, if the current spreader overlaps with the sidewall of the mesa, there is a risk of leakage. Furthermore, the shape of the current spreader also significantly affects characteristics such as luminous uniformity. Therefore, providing a Micro LED chip with high luminous uniformity has become one of the technical challenges urgently needing to be solved by those skilled in the art.

[0004] It should be noted that the information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The present invention provides a light-emitting diode, which includes a semiconductor stack and a transparent conductive layer.

[0006] The semiconductor stack includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked sequentially. The semiconductor stack has a first mesa and a second mesa, with the first mesa exposing the first semiconductor layer and the second mesa exposing the second semiconductor layer. The second mesa is higher than the first mesa. A transparent conductive layer is disposed on top of the second semiconductor layer. Viewed from above, the transparent conductive layer and the second semiconductor layer have the same morphology, and the area of ​​the transparent conductive layer occupies at least 95% of the area of ​​the second semiconductor layer.

[0007] Furthermore, viewed from above, the second platform has an outer edge and an inner edge. The outer edge is farther from the first platform than the inner edge. The shortest distance from the outer edge to the transparent conductive layer is a first spacing, and the shortest distance from the inner edge to the transparent conductive layer is a second spacing. The second spacing is greater than the first spacing.

[0008] Furthermore, the first spacing ranges from 0.5 to 1.5 micrometers.

[0009] Furthermore, the second spacing ranges from 1.5 to 2.5 micrometers.

[0010] Furthermore, the second spacing is at least 1.5 times the first spacing.

[0011] Furthermore, the transparent conductive layer and the second semiconductor layer are etched together to make the transparent conductive layer and the second semiconductor layer have the same morphology.

[0012] Furthermore, the minimum single-sided size of the light-emitting diode ranges from 0.5 to 100 micrometers.

[0013] Furthermore, viewed from above, the first platform is located within the transparent conductive layer.

[0014] Furthermore, the light-emitting diode also includes an electrode layer and an insulating layer, the electrode layer being disposed on the first semiconductor layer, and the insulating layer covering a portion of the semiconductor stack, a portion of the transparent conductive layer, and a portion of the electrode layer.

[0015] Furthermore, the area of ​​the transparent conductive layer is less than 100% of the area of ​​the second semiconductor layer.

[0016] The present invention also provides a light-emitting device, which employs any of the light-emitting diodes provided above.

[0017] The present invention provides a light-emitting diode and a light-emitting device. By disposing a transparent conductive layer with the same morphology as the second semiconductor layer on the second semiconductor layer, and by having the area of ​​the transparent conductive layer be nearly the same as that of the second semiconductor layer, the current diffusion performance of the transparent conductive layer is improved, thereby improving the light emission uniformity of the light-emitting diode and improving the performance of the device.

[0018] By forming a second electrode covering the corner, a light-emitting diode with a side-plated second electrode can be obtained, which facilitates subsequent electrical connections and improves device performance.

[0019] Other features and advantages of the present invention will be set forth in the following description, and some of the technical features and advantages may be apparent from the description or learned by practicing the invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a traditional light-emitting diode; Figure 2A This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present invention; Figure 2B It is along Figure 2A A schematic diagram of the cross-sectional structure intercepted by the intercept line FF; Figure 3 yes Figure 2A Enlarged view of the first platform in the middle; Figure 4 yes Figure 2A Enlarged schematic diagram of the edge of the second platform in the middle; Figure 5 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention.

[0022] Figure label: 10-First semiconductor layer; 12-Light-emitting layer; 14-Second semiconductor layer; 16-Transparent conductive layer; 18-Electrode layer; 20-Insulating layer; 21-First mesa; 22-Second mesa; 30-Outer side; 32-Inner side; L1-First spacing; L2-Second spacing. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."

[0025] Please see Figures 2A to 4 , Figure 2A This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present invention. Figure 2B It is along Figure 2A A schematic diagram of the cross-sectional structure intercepted by the intercept line FF. Figure 3 yes Figure 2A An enlarged view of point 21 on the first platform. Figure 4 yes Figure 2A An enlarged view of the edge of the second platform 22. It should be noted that the attached diagram is for clarity. Figure 2A The opening of the insulating layer 20 is omitted. Figure 3 Electrode layer 18 is omitted. To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a light-emitting diode. As shown in the figure, the light-emitting diode includes a semiconductor stack and a transparent conductive layer 16.

[0026] The semiconductor stack includes a first semiconductor layer 10, a light-emitting layer 12, and a second semiconductor layer 14 stacked sequentially. That is, the light-emitting layer 12 is located between the first semiconductor layer 10 and the second semiconductor layer 14.

[0027] The first semiconductor layer 10 can be an N-type semiconductor layer, which can provide electrons to the light-emitting layer 12 under the influence of a power source. In some embodiments, the first semiconductor layer 10 includes an N-type doped nitride layer. The N-type doped nitride layer may include N-type impurities. N-type impurities may include one or a combination of Si, Ge, and Sn.

[0028] The light-emitting layer 12 can be a quantum well (QW) structure. In some embodiments, the light-emitting layer 12 can also be a multiple quantum well (MQW) structure, wherein the multiple quantum well structure includes multiple quantum well layers (Wells) and multiple quantum barrier layers arranged alternately in a repeating manner, such as a GaN / AlGaN, InAlGaN / InAlGaN, or InGaN / AlGaN multi-quantum well structure. Furthermore, the composition and thickness of the well layers within the light-emitting layer 12 determine the wavelength of the generated light. To improve the luminous efficiency of the light-emitting layer 12, this can be achieved by changing the depth of the quantum wells, the number of paired quantum wells and quantum barriers, the thickness, and / or other characteristics within the light-emitting layer 12.

[0029] The second semiconductor layer 14 can be a P-type semiconductor layer, which can provide holes to the light-emitting layer 12 under power. In some embodiments, the second semiconductor layer 14 includes a P-type doped nitride layer. The P-type doped nitride layer may include one or more P-type impurities. The P-type impurities may include one or a combination of Mg, Zn, and Be. The second semiconductor layer 14 can be a single-layer structure or a multi-layer structure with different compositions.

[0030] In some embodiments, the first semiconductor layer 10, the light-emitting layer 12, and the second semiconductor layer 14 may be formed from materials such as aluminum gallium indium nitride, gallium nitride, aluminum gallium nitride, aluminum indium phosphide, aluminum gallium indium phosphide, gallium arsenide, or aluminum gallium arsenide. The first semiconductor layer 10 or the second semiconductor layer 14 includes a capping layer that provides electrons or holes, and may include other layer materials, such as a current spreading layer, a window layer, or an ohmic contact layer, etc., configured as different multilayers depending on the doping concentration or composition content. The light-emitting layer 12 is the region that provides light radiation for electron-hole recombination, and different materials may be selected according to different emission wavelengths. The light-emitting layer 12 may be a periodic structure of a single quantum well or multiple quantum wells. By adjusting the composition ratio of the semiconductor materials in the light-emitting layer 12, it is desired to radiate light of different wavelengths.

[0031] The semiconductor stack has a first mesa 21 and a second mesa 22. The first mesa 21 exposes the first semiconductor layer 10, and the second mesa 22 exposes the second semiconductor layer 14. The second mesa 22 is higher than the first mesa 21. The second mesa 22 can refer to the upper surface of the second semiconductor layer 14. A portion of the semiconductor stack may have the second semiconductor layer 14 and the light-emitting layer 12 removed to expose the first semiconductor layer 10, forming one or more first mesa 21s. That is, the first mesa 21 is the upper surface of the first semiconductor layer 10 that is not covered by the second semiconductor layer 14 and the light-emitting layer 12, as shown in the figure. The first mesa 21 is used to set the electrode layer 18. The distribution of the first mesa 21 is not limited to that shown in the figure and can be designed according to the actual chip size and shape. The first mesa 21s can be connected together or separated from each other.

[0032] A transparent conductive layer 16 is disposed on the second semiconductor layer 14. The transparent conductive layer 16 is electrically connected to the second semiconductor layer 14. The transparent conductive layer 16 is made of a transparent conductive material, which may include indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium-doped zinc oxide (GZO), tungsten-doped indium oxide (IWO), or zinc oxide (ZnO), but the embodiments disclosed herein are not limited thereto. The transparent conductive layer 16 is completely disposed on the second semiconductor layer 14, that is, the horizontal projection of the transparent conductive layer 16 falls within the horizontal projection of the second platform 22.

[0033] Looking from above, for reference Figure 2A As shown, the transparent conductive layer 16 and the second semiconductor layer 14 have the same morphology. The area of ​​the transparent conductive layer 16 is at least 95% of the area of ​​the second semiconductor layer 14, thereby improving the luminous uniformity of the light-emitting diode and enhancing the device performance. Conventionally, as... Figure 1 The ITO structure shown is mainly distributed on one side of the first mesa 21. This results in poor light emission uniformity, for example... Figure 1The light emission from the left side of the first mesa 21 is significantly less than that from the right side. To address this issue, the present invention modifies the morphology and area ratio of the transparent conductive layer 16. Specifically, the transparent conductive layer 16, which has the same morphology as the second semiconductor layer 14, is disposed on the second semiconductor layer 14, and the area of ​​the transparent conductive layer 16 is nearly identical to that of the second semiconductor layer 14. This improves the current diffusion performance of the transparent conductive layer 16, thereby enhancing the light emission uniformity of the LED and improving the device performance.

[0034] To further clarify, the identical morphology of the transparent conductive layer 16 and the second semiconductor layer 14 means that their appearances are similar or close, but their dimensions do not need to be exactly the same. For example, the second semiconductor layer 14 may have an L-shaped morphology, and the transparent conductive layer 16 may also be L-shaped, but the transparent conductive layer 16 can be an L-shaped layer scaled down by half. In this case, the transparent conductive layer 16 still has the same morphology as the second semiconductor layer 14. Taking the figure as an example, the second semiconductor layer is generally square with a circular notch in the middle, and the transparent conductive layer 16 is also square with a circular notch in the middle, but their areas are not 100% identical and overlapping.

[0035] In some embodiments, the transparent conductive layer 16 and the second semiconductor layer 14 are etched together to make the transparent conductive layer 16 and the second semiconductor layer 14 have the same morphology, simplifying the fabrication process and ensuring the current diffusion performance of the transparent conductive layer 16, thereby improving the light emission uniformity of the light-emitting diode and enhancing the performance of the device.

[0036] In some embodiments, viewed from above, the area of ​​the transparent conductive layer 16 occupies less than 100% of the area of ​​the second semiconductor layer 14. That is, the two layers do not completely overlap, but rather have a non-overlapping outer region, thereby improving device performance. Optionally, the area of ​​the transparent conductive layer 16 occupies 98%, 99%, 99.5%, or 99.9% of the area of ​​the second semiconductor layer 14 to further improve the luminous uniformity of the light-emitting diode and enhance device performance.

[0037] In some embodiments, viewed from above, the second platform 22 has an outer edge 30 and an inner edge 32. The outer edge 30 is farther from the first platform 21 than the inner edge 32, and the inner edge 32 is closer to the first platform 21 than the outer edge 30. The shortest distance from the outer edge 30 to the transparent conductive layer 16 is a first spacing L1, and the shortest distance from the inner edge 32 to the transparent conductive layer 16 is a second spacing L2. The second spacing L2 is greater than the first spacing L1. This arrangement avoids the risk of leakage caused by the transparent conductive layer 16 being too close to the inner edge 32.

[0038] Optionally, the second spacing L2 is at least 1.5 times the first spacing L1. Optionally, the first spacing L1 ranges from 0.5 to 1.5 micrometers. Optionally, the second spacing L2 ranges from 1.5 to 2.5 micrometers.

[0039] In some embodiments, viewed from above, such as Figure 2A As shown, the first mesa 21 is located within the transparent conductive layer 16. That is, the first mesa 21 is completely covered by the transparent conductive layer 16. As a result, since the first mesa 21 is located inside the transparent conductive layer 16, the light emission uniformity of the light-emitting diode is better, further improving the device performance.

[0040] In some embodiments, the light-emitting diode further includes an electrode layer 18 and an insulating layer 20. The electrode layer 18 is disposed on the first semiconductor layer 10, and the insulating layer 20 covers a portion of the semiconductor stack, a portion of the transparent conductive layer 16, and a portion of the electrode layer 18.

[0041] The electrode layer 18 can be a multilayer structure, such as a metal stack structure of Cr / Ti / Ni / Ti / Pt, Cr / Ti / Al / Ni / Au, etc.

[0042] The insulating layer 20 is made of a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material may include silicone. The dielectric material includes electrically insulating materials such as aluminum oxide, silicon nitride, silicon oxide, titanium oxide, or magnesium fluoride. For example, the insulating layer 20 may be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or a combination thereof, such as a Bragg mirror (DBR) formed by repeatedly stacking two materials with different refractive indices.

[0043] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Compared to Figure 2A The main difference in this embodiment of the light-emitting diode is that the first mesa 21 is not completely surrounded by the transparent conductive layer 16, but only a portion of it. In this embodiment, the transparent conductive layer 16 still has the same morphology as the second semiconductor layer 14, and the area of ​​the transparent conductive layer 16 accounts for at least 95% of the area of ​​the second semiconductor layer 14, thereby improving the current diffusion performance of the transparent conductive layer 16 and thus improving the light emission uniformity of the light-emitting diode.

[0044] In this embodiment, the morphology of the second semiconductor in the figure is generally a square with a U-shaped notch, and the morphology of the transparent conductive layer 16 is also a square with a U-shaped notch.

[0045] In this embodiment, the outer edge 30 of the second platform 22 is farther from the first platform 21 than its inner edge 32, while the inner edge 32 is closer to the first platform 21 than the outer edge 30. Furthermore, the second spacing L2 is greater than the first spacing L1 to avoid the risk of leakage caused by the transparent conductive layer 16 being too close to the inner edge 32.

[0046] It should be noted that the shape of the second countertop 22 in this case is not limited to... Figure 2A , Figure 5 The morphology shown can be used for other purposes, as long as the morphology of the transparent conductive layer 16 and the second semiconductor layer 14 are the same, and the area of ​​the transparent conductive layer 16 accounts for at least 95% of the area of ​​the second semiconductor layer 14, the current diffusion performance of the transparent conductive layer 16 can be improved, thereby improving the light emission uniformity of the light-emitting diode.

[0047] In some embodiments, the light-emitting diode is a Micro LED, and the minimum single-sided size of the light-emitting diode ranges from 0.5 to 100 micrometers, or from 0.5 to 50 micrometers.

[0048] An embodiment of the present invention also provides a light-emitting device, which may employ a light-emitting diode from any of the foregoing embodiments.

[0049] In summary, the present invention provides a light-emitting diode and a light-emitting device that improves the current diffusion performance of the transparent conductive layer 16 by disposing a transparent conductive layer 16 with the same morphology as the second semiconductor layer 14 on the second semiconductor layer 14, and by having the area of ​​the transparent conductive layer 16 nearly the same as that of the second semiconductor layer 14, thereby improving the light emission uniformity of the light-emitting diode and improving the performance of the device.

[0050] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting diode, characterized in that: The light-emitting diode includes: A semiconductor stack, comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer stacked sequentially, the semiconductor stack having a first mesa and a second mesa, the first mesa exposing the first semiconductor layer, the second mesa exposing the second semiconductor layer, and the second mesa being higher than the first mesa. A transparent conductive layer is disposed on the second semiconductor layer; From a top view, the transparent conductive layer and the second semiconductor layer have the same morphology, and the area of ​​the transparent conductive layer accounts for at least 95% of the area of ​​the second semiconductor layer.

2. The light-emitting diode according to claim 1, characterized in that: Viewed from above, the second platform has an outer edge and an inner edge. The outer edge is farther from the first platform than the inner edge. The shortest distance from the outer edge to the transparent conductive layer is a first spacing, and the shortest distance from the inner edge to the transparent conductive layer is a second spacing. The second spacing is greater than the first spacing.

3. The light-emitting diode according to claim 2, characterized in that: The first spacing ranges from 0.5 to 1.5 micrometers.

4. The light-emitting diode according to claim 2, characterized in that: The second spacing ranges from 1.5 to 2.5 micrometers.

5. The light-emitting diode according to claim 2, characterized in that: The second spacing is at least 1.5 times the first spacing.

6. The light-emitting diode according to claim 1, characterized in that: The transparent conductive layer and the second semiconductor layer are etched together to make the transparent conductive layer and the second semiconductor layer have the same morphology.

7. The light-emitting diode according to claim 1, characterized in that: The minimum single-sided size of the light-emitting diode ranges from 0.5 to 100 micrometers.

8. The light-emitting diode according to claim 1, characterized in that: Viewed from above, the first platform is located within the transparent conductive layer.

9. The light-emitting diode according to claim 1, characterized in that: The light-emitting diode further includes an electrode layer and an insulating layer. The electrode layer is disposed on the first semiconductor layer, and the insulating layer covers a portion of the semiconductor stack, a portion of the transparent conductive layer, and a portion of the electrode layer.

10. The light-emitting diode according to claim 1, characterized in that: The area of ​​the transparent conductive layer is less than 100% of the area of ​​the second semiconductor layer.

11. A light-emitting device, characterized in that: The light-emitting device is a light-emitting diode as described in any one of claims 1 to 10.

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