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 which comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer, the first semiconductor layer is provided with a first surface and a second surface which are opposite, the light-emitting layer is arranged on the first surface of the first semiconductor layer, and the second semiconductor layer is arranged on the light-emitting layer. The light-emitting layer is located between the first semiconductor layer and the second semiconductor layer, the light-emitting diode is provided with a table top and a concave hole, the table top is a first surface, not covered by the light-emitting layer, of the first semiconductor layer, the second semiconductor layer extends towards the first semiconductor layer to form the concave hole, and the concave hole is formed by the second semiconductor layer when being overlooked towards the first semiconductor layer from the upper portion of the light-emitting diode. The recessed hole is closer to the center point of the first semiconductor layer than the mesa. By means of the arrangement, lighting diffusion of the light-emitting diode can be effectively improved, and the brightness and the heat sink of the light-emitting diode are increased.

Description

Technical Field

[0001] The present invention 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 light-emitting element, usually made of semiconductors such as GaN, GaAs, GaP, GaAsP, etc., and its core is a PN junction with light-emitting characteristics. LED has the advantages of high luminous intensity, high efficiency, small size, and long service life, and is considered to be one of the most promising light sources at present. LED has been widely used in lighting, monitoring and command, high-definition broadcasting, high-end cinemas, office displays, conference interactions, virtual reality and other fields. In recent years, LEDs generally have the problems of low brightness and low luminous efficiency. Therefore, how to solve this problem has become one of the difficulties that technicians in this field need to solve urgently.

[0003] It should be noted that the information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as admitting or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0004] The present invention provides a light-emitting diode, which includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer. The first semiconductor layer has a first surface and a second surface opposite to each other. The light-emitting layer is arranged on the first surface of the first semiconductor layer. The second semiconductor layer is arranged on the light-emitting layer. The light-emitting diode has a table and a concave hole, wherein the table is the first surface of the first semiconductor layer not covered by the light-emitting layer, and the concave hole extends from the second semiconductor layer to the first semiconductor layer, and when looking down from the top of the light-emitting diode toward the first semiconductor layer, the concave hole is closer to the center point of the first semiconductor layer than the table.

[0005] The present invention further provides a light emitting device, which includes a circuit board and a light emitting diode. The light emitting diode is arranged on the circuit board, and the light emitting diode can be the light emitting diode of any of the above embodiments.

[0006] An embodiment of the present invention provides a light emitting diode and a light emitting device, which can effectively improve the lighting diffusion of the light emitting diode and increase the brightness and heat sink of the light emitting diode by setting a concave hole and a table.

[0007] Other features and beneficial effects of the present invention will be described in the following description, and some of the technical features and beneficial effects can be obviously derived from the description or understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0009] Figure 1 is a schematic structural diagram of a light emitting diode provided by an embodiment of the present invention;

[0010] Figure 2 is along Figure 1 A schematic cross-sectional view taken along the interception line FF;

[0011] Figure 3 It is a schematic diagram of the central area and edge area of ​​the first semiconductor layer provided by one embodiment of the present invention.

[0012] Reference numerals:

[0013] 12-first semiconductor layer; 121-first surface; 122-second surface; 123-edge region; 124-central region; 14-light-emitting layer; 16-second semiconductor layer; 18-table; 20-recess; 22-insulating layer; 221-first opening; 222-second opening; 223-third opening; 24-first electrode; 26-second electrode; Z-center point; H1-first vertical distance from table to second surface; H2-second vertical distance from recess to second surface; L1-size of recess; L2-minimum spacing between recess and table. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0015] In the description of the present invention, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variation thereof all mean "at least including".

[0016] See also Figure 1 , Figure 2 and Figure 3 , Figure 1 is a schematic diagram of the structure of a light emitting diode provided by an embodiment of the present invention, Figure 2 is along Figure 1 A schematic cross-sectional view of the interception line FF, Figure 3 1 is a schematic diagram of a central region 124 and an edge region 123 of a first semiconductor layer 12 provided in an embodiment of the present invention. To achieve at least one of the above advantages or other advantages, an embodiment of the present invention provides a light emitting diode. As shown in the figure, the light emitting diode includes a first semiconductor layer 12, a light emitting layer 14 and a second semiconductor layer 16.

[0017] The first semiconductor layer 12 has a first surface 121 and a second surface 122 opposite to each other. In the present embodiment, the first surface 121 and the second surface 122 are the lower surface and the upper surface of the first semiconductor layer 12, respectively. The first semiconductor layer 12 may be an N-type semiconductor layer, which may provide electrons to the light-emitting layer 14 under the action of a power source. In some embodiments, the first semiconductor layer 12 includes an N-type doped nitride layer. The N-type doped nitride layer may include N-type impurities. The N-type impurities may include one of Si, Ge, Sn, or a combination thereof.

[0018] The light emitting layer 14 is disposed on the first surface 121 of the first semiconductor layer 12. The light emitting layer 14 may be a quantum well structure (Quantum Well, referred to as QW). In some embodiments, the light emitting layer 14 may also be a multiple quantum well structure (Multiple Quantum Well, referred to as MQW), wherein the multiple quantum well structure includes multiple quantum well layers (Well) and multiple quantum barrier layers (Barrier) alternately arranged in a repeated manner, for example, it may be a multiple quantum well structure of GaN / AlGaN, InAlGaN / InAlGaN or InGaN / AlGaN. In addition, the composition and thickness of the well layer in the light emitting layer 14 determine the wavelength of the generated light. In order to improve the luminous efficiency of the light emitting layer 14, it can be achieved by changing the depth of the quantum well, the number of layers, thickness and / or other features of the paired quantum wells and quantum barriers in the light emitting layer 14.

[0019] The second semiconductor layer 16 is disposed on the light emitting layer 14. That is, the light emitting layer 14 is located between the first semiconductor layer 12 and the second semiconductor layer 16. The second semiconductor layer 16 may be a P-type semiconductor layer, which may provide holes to the light emitting layer 14 under the action of a power source. In some embodiments, the second semiconductor layer 16 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 16 may be a single-layer structure or a multi-layer structure, and the multi-layer structure has different compositions.

[0020] The light-emitting diode has a table 18 and a recessed hole 20. The table 18 is a first surface 121 of the first semiconductor layer 12 that is not covered by the light-emitting layer 14. That is, the second semiconductor layer 16 and the light-emitting layer 14 corresponding to the table 18 are removed to expose the first semiconductor layer 12, thereby forming the table 18. As shown in the figure, the table 18 can be used to set the first electrode 24 later. The distribution of the table 18 is not limited to that shown in the figure and can be designed according to the actual chip size and shape. In some embodiments, the table 18 can be a surrounding table 18, such as a circle around the light-emitting layer 14 is provided with a table 18. In some embodiments, the table 18 and the recessed hole 20 can be formed by a single process.

[0021] The concave hole 20 extends from the second semiconductor layer 16 to the first semiconductor layer 12. It should be noted that the concave hole 20 does not completely penetrate the entire first semiconductor layer 12, but extends to a certain depth inside the first semiconductor layer 12. Looking down from the top of the light emitting diode toward the first semiconductor layer 12, as shown in FIG. Figure 1As shown, the concave hole 20 is closer to the center point Z of the first semiconductor layer 12 than the table 18. The so-called center point Z refers to the position of the center. When the morphology of the first semiconductor layer 12 is a regular figure, the center point Z can be the geometric center point Z of the regular figure. When the morphology of the first semiconductor layer 12 is an irregular figure, the center point Z is more difficult to determine. The center point Z can refer to an area roughly corresponding to the center of the irregular figure. With this design, the table 18 and the concave hole 20 are used as current diffusion paths at the same time, which can effectively improve the lighting diffusion of the light-emitting diode and increase the brightness and heat sink of the light-emitting diode; at the same time, since the concave hole 20 is close to the center point Z of the first semiconductor layer 12, the current diffuses radially, which is conducive to current diffusion; and it can maximize the possibility of ensuring that the areas of the first electrode 24 and the second electrode 26 set later are equal, thereby increasing the electrical contact area between the two electrodes and the substrate and improving the reliability of the device. When only the table 18 is designed, the current flows directly from the p-type semiconductor to the n-electrode, which is not conducive to current diffusion.

[0022] In some embodiments, the first vertical distance H1 from the table 18 to the second surface 122 is greater than the second vertical distance H2 from the recessed hole 20 to the second surface 122. In other words, the recessed hole 20 is deeper than the table 18, so that the current flows to the table 18 and the recessed hole 20 evenly distributed, and the current path is shorter, which can further improve the current expansion effect. Optionally, the first vertical distance H1 can range from 0.5 to 2.5 μm, and the second vertical distance H2 can range from 0.5 to 2.5 μm. In some embodiments, the first vertical distance H1 can also be equal to the second vertical distance H2, or the first vertical distance H1 can be less than the second vertical distance H2.

[0023] In some embodiments, Figure 3 As shown, the first semiconductor layer 12 has an edge region 123 and a central region 124. The mesas 18 are located in the edge region 123, and the recesses 20 are located in the central region 124. In the figure, the edge region 123 and the central region 124 are shown with different shades.

[0024] Looking down from the top of the light-emitting diode toward the first semiconductor layer 12, the central region 124 refers to a region formed by extending from the center point Z of the first semiconductor layer 12 to the side of the first semiconductor layer 12, and the horizontal projection area of ​​the central region 124 is between 10% and 45% of the horizontal projection area of ​​the first semiconductor layer 12, and the distances extending to each side may be different. Alternatively, the central region 124 refers to a region formed by extending from the center point Z of the first semiconductor layer 12 to each side of the first semiconductor layer 12, and the distances extending to each side may be different, and the central region 124 may be an irregular shape, and the length of the longest line segment in the central region 124 is between 5 and 85 microns.

[0025] Looking down from the top of the light-emitting diode toward the first semiconductor layer 12, the edge region 123 refers to the region formed by the side edges of the first semiconductor layer 12 extending toward the center point Z of the first semiconductor layer 12, and the horizontal projection area of ​​the peripheral region is between 55% and 90% of the horizontal projection area of ​​the light-emitting layer 14, and the spreading distances of the side edges may be different. The peripheral region may be an irregular shape. In some embodiments, there is a blank area between the edge region 123 and the center region 124, that is, the edge region 123 is not connected to the center region 124; or, there are some overlapping areas between the edge region 123 and the center region 124, etc.

[0026] In some embodiments, looking down at the first semiconductor layer 12 from above the light-emitting diode, the area of ​​the recessed hole 20 accounts for 2% to 20% of the area of ​​the first semiconductor layer 12, and the area of ​​the mesa 18 accounts for 5% to 35% of the area of ​​the first semiconductor layer 12, so as to further enhance the current diffusion effect.

[0027] In order to further improve the current diffusion effect, the size L1 of the concave hole 20 can be in the range of 0.5 to 15 microns. The minimum spacing L2 between the concave hole 20 and the table 18 can be in the range of 0.5 to 20 microns. If L1 is too small, it will be detrimental to the diffusion of current. If L1 is too large, it will affect the light emission of the light-emitting layer 14. If L2 is too small, the possibility of mutual interference will increase. If L2 is too large, it will affect the photoelectric performance.

[0028] The light emitting diode further includes an insulating layer 22 , a first electrode 24 and a second electrode 26 .

[0029] The insulating layer 22 covers the first semiconductor layer 12, the light emitting layer 14 and the second semiconductor layer 16. The insulating layer 22 has a first opening 221, a second opening 222 and a third opening 223. The first opening 221 exposes the table 18, the second opening 222 exposes the recessed hole 20, and the third opening 223 exposes the second semiconductor layer 16. The material of the insulating layer 22 includes a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material may include silica gel. The dielectric material includes an electrically insulating material such as aluminum oxide, silicon nitride, silicon oxide, titanium oxide, or magnesium fluoride. For example, the insulating layer 22 may be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate or a combination thereof, and the combination thereof may be, for example, a Bragg reflector (DBR) formed by repeatedly stacking two materials with different refractive indices.

[0030] The first electrode 24 is disposed on the insulating layer 22 and electrically connected to the first semiconductor layer 12 through the first opening 221 and the second opening 222. The first electrode 24 covers the first opening 221 and the second opening 222, ensuring that the first electrode 24 has a sufficiently large area to facilitate subsequent electrical contact with the substrate.

[0031] The second electrode 26 is disposed on the insulating layer 22 and is electrically connected to the second semiconductor layer 16 through the third opening 223. In some embodiments, the surface of the first electrode 24 is flush with the surface of the second electrode 26 to improve the stability of the device. The first electrode 24 and the second electrode 26 can be metal pads, which are made of metal materials. It can be a single-layer, double-layer or multi-layer structure, for example: Ti / Al, Ti / Al / Ti / Au, Ti / Al / Ni / Au, V / Al / Pt / Au and other stacked structures.

[0032] In some embodiments, the light emitting diode is a Micro LED, and the size of the light emitting diode may be less than or equal to 100 μm.

[0033] In some embodiments, the recessed hole 20 and the mesa 18 can be realized by a MESA mask, thereby effectively controlling the etching angle to facilitate the subsequent better growth of the insulating layer 22 to protect the sidewalls, and less prone to sidewall defects, and can effectively increase the process window area to minimize the chip walkway.

[0034] The present invention further provides a light emitting device, which includes a circuit board and a light emitting diode. The light emitting diode is arranged on the circuit board, and the light emitting diode can be the light emitting diode of any of the above embodiments.

[0035] An embodiment of the present invention provides a light emitting diode and a light emitting device, which can effectively improve the lighting diffusion of the light emitting diode and increase the brightness and heat sink of the light emitting diode by distributing the concave holes 20 and the mesas 18 .

[0036] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light emitting diode, characterized in that: The light emitting diode comprises: A first semiconductor layer having a first surface and a second surface opposite to each other; A light emitting layer is disposed on the first surface of the first semiconductor layer; A second semiconductor layer is disposed on the light emitting layer; The light-emitting diode has a table and a recessed hole, the table is the first surface of the first semiconductor layer not covered by the light-emitting layer, the recessed hole extends from the second semiconductor layer to the first semiconductor layer, and when looking down from the top of the light-emitting diode toward the first semiconductor layer, the recessed hole is closer to the center point of the first semiconductor layer than the table.

2. The light emitting diode according to claim 1, characterized in that: A first vertical distance from the mesa to the second surface is greater than a second vertical distance from the recessed hole to the second surface.

3. The light emitting diode according to claim 2, characterized in that: The first vertical distance ranges from 0.5 to 2.5 μm.

4. The light emitting diode according to claim 2, characterized in that: The second vertical distance ranges from 0.5 to 2.5 μm.

5. The light emitting diode according to claim 1, characterized in that: The first semiconductor layer has an edge region and a central region, the mesa is located in the edge region, and the concave hole is located in the central region.

6. The light emitting diode according to claim 5, characterized in that: Looking down from the top of the light-emitting diode toward the first semiconductor layer, the central region refers to a region extending from the center point of the first semiconductor layer to the side edges of the first semiconductor layer, and the horizontal projection area of ​​the central region is between 10% and 45% of the horizontal projection area of ​​the first semiconductor layer; or, the central region refers to a region extending from the center point of the first semiconductor layer to the side edges of the first semiconductor layer, and the length of the longest line segment in the central region is between 5 and 85 microns; Looking down toward the first semiconductor layer from above the light-emitting diode, the edge region refers to a region formed by extending the side edges of the first semiconductor layer toward the center point of the first semiconductor layer, and the horizontal projection area of ​​the peripheral region is between 55% and 90% of the horizontal projection area of ​​the light-emitting layer.

7. The light emitting diode according to claim 1, characterized in that: Looking down toward the first semiconductor layer from above the light emitting diode, the area of ​​the concave hole accounts for 2% to 20% of the area of ​​the first semiconductor layer, and the area of ​​the terrace accounts for 5% to 35% of the area of ​​the first semiconductor layer.

8. The light emitting diode according to claim 1, characterized in that: The size of the concave holes ranges from 0.5 to 15 microns.

9. The light emitting diode according to claim 1, characterized in that: The minimum distance between the concave hole and the terrace is in the range of 0.5 to 15 microns.

10. The light emitting diode according to claim 1, characterized in that: The light-emitting diode also includes an insulating layer, a first electrode and a second electrode, the insulating layer covers the first semiconductor layer, the light-emitting layer and the second semiconductor layer, the insulating layer has a first opening, a second opening and a third opening, the first opening exposes the table, the second opening exposes the recessed hole, and the third opening exposes the second semiconductor layer, the first electrode is arranged on the insulating layer and is electrically connected to the first semiconductor layer through the first opening and the second opening, and the second electrode is arranged on the insulating layer and is electrically connected to the second semiconductor layer through the third opening.

11. The light emitting diode according to claim 10, characterized in that: The first electrode is flush with the surface of the second electrode.

12. The light emitting diode according to claim 10, characterized in that: The first electrode covers the first opening and the second opening.

13. The light emitting diode according to claim 1, characterized in that: The size of the light emitting diode is less than or equal to 100 μm.

14. A light emitting device, characterized in that: The light emitting device comprises a circuit board and a light emitting diode. The light emitting diode is arranged on the circuit board. The light emitting diode is the light emitting diode according to any one of claims 1 to 13.

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