Light emitting diode

Abstract

The utility model provides a light emitting diode. The light emitting diode comprises a substrate; the epitaxial layer comprises a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer which are stacked on the substrate in sequence, the doping type of the first semiconductor layer is opposite to that of the second semiconductor layer, a groove is formed in the epitaxial layer, the groove at least extends into part of the second semiconductor layer, and the first semiconductor layer and the second semiconductor layer are stacked on the epitaxial layer. The cross section of the groove is non-linear; a first electrode on the second semiconductor layer; and the second electrode is positioned on the surface, far away from the epitaxial layer, of the substrate. According to the technical scheme of the utility model, the luminous efficiency of the light-emitting diode can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a light emitting diode. Background Art

[0002] Light Emitting Diode (LED) is a commonly used light-emitting device that emits light by releasing energy through the recombination of electrons and holes. It is widely used in lighting, display and other fields. People's demand for lighting is getting higher and higher, and the "light quality" of LEDs has received widespread attention. High-quality LEDs should have the characteristics of low color temperature, high color rendering index and high light efficiency. At present, there is still much room for improvement in the luminous efficiency of LEDs.

[0003] Therefore, it is necessary to provide a light emitting diode to further improve the light emitting efficiency of the light emitting diode. Utility Model Content

[0004] The utility model aims to provide a light emitting diode, which can improve the light emitting efficiency of the light emitting diode.

[0005] To achieve the above object, the utility model provides a light emitting diode, comprising:

[0006] substrate;

[0007] An epitaxial layer, comprising a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer stacked in sequence on the substrate, wherein the first semiconductor layer and the second semiconductor layer have opposite doping types, a groove is formed in the epitaxial layer, the groove extends into at least a portion of the second semiconductor layer, and the cross-sectional shape of the groove is non-straight line;

[0008] A first electrode, located on the second semiconductor layer;

[0009] The second electrode is located on a surface of the substrate away from the epitaxial layer.

[0010] Optionally, the trench penetrates the epitaxial layer.

[0011] Optionally, the cross-sectional shape of the groove is a broken line or a wavy line or a combination of a broken line and a wavy line.

[0012] Optionally, the width of the groove is 5 μm to 100 μm.

[0013] Optionally, the light emitting diode further comprises:

[0014] The extended electrode is located on the second semiconductor layer, the extended electrode is electrically connected to the first electrode, and the groove is located between two adjacent extended electrodes.

[0015] Optionally, the groove is located in the middle between two adjacent extended electrodes.

[0016] Optionally, the distance between the groove and the extended electrodes on both sides of the groove is 1 / 3 of the distance between two adjacent extended electrodes.

[0017] Optionally, the extended electrode comprises:

[0018] A plurality of first parts, wherein the first parts extend in a first direction, and the first parts are arranged in sequence in a second direction, and the groove is located between two adjacent first parts;

[0019] The second portion extends in a second direction and is electrically connected to the first portion.

[0020] Optionally, one end of the extended electrode is connected to the first electrode, and the other end of the extended electrode extends in a direction away from the first electrode.

[0021] Optionally, the light emitting diode further comprises:

[0022] A protection layer is located on the side walls of the substrate and the epitaxial layer and on the inner wall of the trench.

[0023] Optionally, the protective layer has a thickness of 0.1 μm to 1 μm.

[0024] Optionally, when the doping type of the first semiconductor layer is P type and the doping type of the second semiconductor layer is N type, the light emitting diode further includes:

[0025] a reflector layer, located between the first semiconductor layer and the substrate;

[0026] A bonding layer is located between the reflector layer and the substrate.

[0027] Compared with the prior art, the light-emitting diode of the utility model comprises: a substrate; an epitaxial layer, comprising a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence on the substrate, the first semiconductor layer and the second semiconductor layer have opposite doping types, a groove is formed in the epitaxial layer, the groove at least extends into a portion of the second semiconductor layer, and the cross-sectional shape of the groove is non-linear; a first electrode is located on the second semiconductor layer; and a second electrode is located on a surface of the substrate away from the epitaxial layer, so that the light-emitting efficiency of the light-emitting diode can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1a is a schematic top view of a light emitting diode according to the first embodiment of the utility model;

[0029] Figure 1b is a schematic top view of a light emitting diode according to a second embodiment of the utility model;

[0030] Figure 1c is a top view schematic diagram of a light emitting diode according to Embodiment 3 of the present utility model;

[0031] Figure 1d is a schematic top view of a light emitting diode according to a fourth embodiment of the utility model;

[0032] Figure 1e is a top view schematic diagram of a light emitting diode according to a fifth embodiment of the utility model;

[0033] Figure 2 It is a structural schematic diagram of a light emitting diode according to an embodiment of the utility model;

[0034] Figure 3 It is a structural schematic diagram of a light emitting diode according to another embodiment of the utility model;

[0035] Figure 4 It is a schematic diagram of the light path of a light emitting diode according to an embodiment of the utility model.

[0036] Among them, Figure 1a to Figure 4 The reference numerals are described as follows:

[0037] 11-substrate; 12-epitaxial layer; 121-first semiconductor layer; 122-multi-quantum well layer; 123-second semiconductor layer; 13-groove; 14-first electrode; 15-extended electrode; 151-first part; 152-second part; 16-second electrode; 17-bonding layer. DETAILED DESCRIPTION

[0038] In order to make the purpose, advantages and features of the present invention more clear, the light emitting diode proposed by the present invention is further described in detail below. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0039] An embodiment of the utility model provides a light-emitting diode, comprising: a substrate; an epitaxial layer, comprising a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer stacked in sequence on the substrate, wherein the first semiconductor layer and the second semiconductor layer have opposite doping types, a groove is formed in the epitaxial layer, the groove extends into at least a portion of the second semiconductor layer, and the cross-sectional shape of the groove is non-linear; a first electrode is located on the second semiconductor layer; and a second electrode is located on a surface of the substrate away from the epitaxial layer.

[0040] See below Figure 1a to Figure 4 The light emitting diode provided in this embodiment is described in more detail. Figure 2-Figure 3 Too Figure 1a Schematic diagram of the longitudinal section along the AA' direction, Figure 1b to Figure 1e and Figure 1a The difference is that the distribution of the first electrode 14, the extended electrode 15 and the groove 13 and the cross-sectional shape of the groove 13 are different. Figure 4 Only a portion of the epitaxial layer 12 and the trench 13 are shown schematically.

[0041] The material of the substrate 11 can be at least one of semiconductor materials such as silicon, germanium, silicon carbide, gallium arsenide, gallium nitride and gallium oxide, and the conductive properties can be changed by doping the substrate 11.

[0042] In one embodiment, the thickness of the substrate 11 may be 100 μm to 500 μm.

[0043] The epitaxial layer 12 includes a first semiconductor layer 121, a multi-quantum well layer 122 and a second semiconductor layer 123 stacked in sequence on the substrate 11, the first semiconductor layer 121 and the second semiconductor layer 123 have opposite doping types, a groove 13 is formed in the epitaxial layer 12, and the groove 13 extends into at least a portion of the second semiconductor layer 123, and the cross-sectional shape of the groove 13 is non-straight.

[0044] The multi-quantum well layer 122 is a light-emitting layer, and the multi-quantum well layer 122 includes a confined field that provides holes and electrons for radiation recombination. The side of the second semiconductor layer 123 away from the multi-quantum well layer 122 is a positive light-emitting side.

[0045] The first semiconductor layer 121 may include a first ohmic contact layer, a first window layer, and a first confinement layer stacked sequentially from bottom to top, and the second semiconductor layer 123 may include a second confinement layer, a second window layer, and a second ohmic contact layer stacked sequentially from bottom to top, but are not limited thereto.

[0046] The material of the first semiconductor layer 121 may be at least one of GaN, AlGaN, GaAs, AlGaInP and SiC, etc.; the material of the second semiconductor layer 123 may be at least one of GaN, AlGaN, BAlN, GaAs, AlGaInP and SiC, etc.; the material of the multi-quantum well layer 122 may be at least one of AlN, GaN, AlGaN, InGaN, AlInGaN, GaAs, AlGaInP and SiC, etc. It should be noted that the materials of the first semiconductor layer 121, the second semiconductor layer 123 and the multi-quantum well layer 122 are not limited to the above-mentioned types.

[0047] When the doping type of the first semiconductor layer 121 is P-type, the doping type of the second semiconductor layer 123 is N-type; when the doping type of the first semiconductor layer 121 is N-type, the doping type of the second semiconductor layer 123 is P-type. The P-type dopant may be at least one of elements such as C, Mg, Zn, Ca, Sr and Ba, and the N-type dopant may be at least one of elements such as Si, Ge and Sn.

[0048] Preferably, the groove 13 penetrates the epitaxial layer 12, so that it is easier to control the position where the etching stops when etching to form the groove 13, and the lateral light output area is maximized. In other embodiments, the groove 13 may be located in the second semiconductor layer 123, but does not penetrate the second semiconductor layer 123; or, the groove 13 may just penetrate the second semiconductor layer 123; or, the groove 13 may penetrate the second semiconductor layer 123 and extend into the multi-quantum well layer 122, but does not penetrate the multi-quantum well layer 122; or, the groove 13 may just penetrate the second semiconductor layer 123 and the multi-quantum well layer 122; or, the groove 13 may penetrate the second semiconductor layer 123 and the multi-quantum well layer 122 and extend into the first semiconductor layer 121, but does not penetrate the first semiconductor layer 121.

[0049] The cross-sectional shape of the groove 13 may be a fold line or a wavy line, or the cross-sectional shape of the groove 13 may be a combination of a fold line and a wavy line. Figure 1a to Figure 1d As shown, the cross-sectional shape of the groove 13 is a broken line; Figure 1e As shown, the cross-sectional shape of the groove 13 is a wavy line. When the cross-sectional shape of the groove 13 includes a fold line, the shape of the fold line is arbitrary and can be Figure 1a to Figure 1c The square wave shape shown can also be Figure 1d The cross-sectional shape of the groove 13 is not limited to Figure 1a to Figure 1e The embodiment shown.

[0050] In one embodiment, the sidewall of the groove 13 is a flat surface; or, in another embodiment, the sidewall of the groove 13 is a roughened surface.

[0051] Preferably, the width of the groove 13 is 5 μm to 100 μm, so as to ensure that the sidewall of the groove 13 can smoothly emit light, while avoiding the loss of too much epitaxial layer 12 that leads to a reduction in the forward light emission area.

[0052] The light emitting diode further includes a first electrode 14 located on the second semiconductor layer 123 .

[0053] The light emitting diode further includes: an extended electrode 15 located on the second semiconductor layer 123 , the extended electrode 15 is electrically connected to the first electrode 14 , and the groove 13 is located between two adjacent extended electrodes 15 .

[0054] The first electrode 14 is used for bonding; the expansion electrode 15 is used for current expansion, so that the current in the vertical direction is expanded in the horizontal direction.

[0055] The thickness of the first electrode 14 is greater than or equal to the thickness of the extended electrode 15 .

[0056] Preferably, the groove 13 is located in the middle between two adjacent extended electrodes 15 .

[0057] Preferably, the distance between the groove 13 and the extended electrodes 15 on both sides of the groove 13 is 1 / 3 of the distance between two adjacent extended electrodes 15 .

[0058] like Figure 1a , Figure 1c to Figure 1e As shown, the extended electrode 15 may include:

[0059] A plurality of first portions 151, wherein the first portions 151 extend in a first direction, and the first portions 151 are sequentially spaced apart in a second direction, and the groove 13 is located between two adjacent first portions 151;

[0060] The second portion 152 extends in the second direction, the second portion 152 is electrically connected to the first portion 151 , and the first portion 151 and the second portion 152 are electrically connected to the first electrode 14 .

[0061] The angle between the first direction and the second direction may be any angle. Preferably, the first direction and the second direction are perpendicular to each other.

[0062] Among them, preferably, Figure 1a , Figure 1d and Figure 1e As shown, the first electrode 14 is located at the center of the second semiconductor layer 123, one end of the second portion 152 is connected to the first electrode 14, and the other end of the second portion 152 extends in the second direction, one end of each first portion 151 is connected to the second portion 152 or the first electrode 14, and the other end of each first portion 151 extends in the first direction, and the first portion 151 and the second portion 152 are centrally symmetrically distributed with the first electrode 14 as the center. In other embodiments, as Figure 1c As shown, the first electrode 14 may be located at a non-central position on the second semiconductor layer 123 .

[0063] Or, if Figure 1b As shown, one end of each of the extended electrodes 15 is connected to the first electrode 14, and the other end of each of the extended electrodes 15 extends in a direction away from the first electrode 14, and the groove 13 is located between two adjacent extended electrodes 15. Preferably, each of the extended electrodes 15 is centrally symmetrically distributed with the first electrode 14 as the center.

[0064] The distribution of the first electrode 14, the extended electrode 15 and the groove 13 is not limited to Figure 1a to Figure 1e The embodiment shown.

[0065] The cross-sectional shape of the first electrode 14 can be circular (eg Figure 1a to Figure 1e as shown), semicircular, rectangular or polygonal, etc.

[0066] The light emitting diode further includes a protective layer (not shown) located on the side walls of the substrate 11 and the epitaxial layer 12 and the inner wall of the trench 13 to protect the side walls of the substrate 11 and the epitaxial layer 12 and the inner wall of the trench 13 .

[0067] The material of the protective layer can be at least one of insulating materials such as silicon nitride, silicon oxide and silicon oxynitride.

[0068] The thickness of the protective layer is 0.1 μm to 1 μm.

[0069] In addition, when the doping type of the first semiconductor layer 121 is P type and the doping type of the second semiconductor layer 123 is N type, as shown in FIG. Figure 2 As shown, the light emitting diode further includes:

[0070] A reflector layer (not shown), located between the first semiconductor layer 121 and the substrate 11;

[0071] The bonding layer 17 is located between the reflector layer and the substrate 11. At this time, the light emitting diode is a reverse polarity light emitting diode.

[0072] When the doping type of the first semiconductor layer 121 is N-type and the doping type of the second semiconductor layer 123 is P-type, as Figure 3 As shown, the light emitting diode does not include the bonding layer 17 and the reflector layer. In this case, the light emitting diode is a positive polarity light emitting diode.

[0073] The bonding layer 17 may be made of at least one of metal materials such as Au and Sn, and the reflector layer may be made of at least one of metal materials such as Ni, Ag, Cu, Al, Rh and Au.

[0074] The light emitting diode further includes a second electrode 16 located on a surface of the substrate 11 away from the epitaxial layer 12 .

[0075] The light emitting diode may be, for example, a red light emitting diode.

[0076] The manufacturing method of the light emitting diode is described below:

[0077] When the doping type of the first semiconductor layer 121 is P-type and the doping type of the second semiconductor layer 123 is N-type, the manufacturing method of the light-emitting diode may include: first, providing a first substrate (not shown), and sequentially forming the second semiconductor layer 123, the multi-quantum well layer 122 and the first semiconductor layer 121 on the first substrate; then, forming the reflector layer on the first semiconductor layer 121; then, forming the bonding layer 17 on the reflector layer; then, providing a second substrate, and bonding the second substrate to the reflector layer through the bonding layer 17. ; Then, the first substrate is removed. At this time, the second substrate is the substrate 11. The light-emitting diode includes the substrate 11 and the bonding layer 17, the reflector layer, the first semiconductor layer 121, the multi-quantum well layer 122 and the second semiconductor layer 123 stacked in sequence on the substrate 11. The first semiconductor layer 121, the multi-quantum well layer 122 and the second semiconductor layer 123 constitute the epitaxial layer 12; Then, a first patterned photoresist layer exposing a portion of the second semiconductor layer 123 is formed by coating and photolithography, and then a vacuum A metal material is formed on the exposed second semiconductor layer 123 and the first patterned photoresist layer by a thermal evaporation or electron beam physical vapor deposition process, and the first patterned photoresist layer and the metal material thereon are removed by a stripping process, and the metal material on the second semiconductor layer 123 is retained as the first electrode 14; then, a second patterned photoresist layer is formed to expose a portion of the second semiconductor layer 123 by a coating and photolithography process, and a metal material is formed on the exposed second semiconductor layer 123 and the second patterned photoresist layer by a vacuum thermal evaporation or electron beam physical vapor deposition process. On the photoresist layer, a stripping process is used to remove the second patterned photoresist layer and the metal material thereon, and the metal material retained on the second semiconductor layer 123 is used as the extended electrode 15; then, a dry etching process is used to etch the epitaxial layer 12 not covered by the first electrode 14 and the extended electrode 15 to form the groove 13 in the epitaxial layer 12; then, a protective layer is formed by vapor deposition on the side walls of the substrate 11 and the epitaxial layer 12 and on the inner wall of the groove 13; then, the second electrode 16 is formed on the surface of the substrate 11 away from the epitaxial layer 12.

[0078] When the doping type of the first semiconductor layer 21 is N-type and the doping type of the second semiconductor layer 123 is P-type, the method for manufacturing the light-emitting diode may include: first, providing the substrate 11; then, sequentially forming the first semiconductor layer 121, the multi-quantum well layer 122 and the second semiconductor layer 123 on the substrate 11; then, forming the first electrode 14, the extended electrode 15, the groove 13, the protective layer and the second electrode 16 according to the above-mentioned method for manufacturing a light-emitting diode.

[0079] like Figure 4 As shown, since the groove 13 is formed in the epitaxial layer 12, the light emitted by the multi-quantum well layer 122 is not only emitted along a direction perpendicular to the second semiconductor layer 123 and away from a side of the multi-quantum well layer 122 (i.e., the L1 direction), but also emitted along the side wall direction of the groove 13 (i.e., the L2 direction). That is, the light emission direction of the light-emitting diode of the utility model not only includes the forward light emission along the L1 direction of the existing light-emitting diode, but also adds the lateral light emission along the L2 direction. After entering the groove 13, the light emitted from the side wall of the groove 13 is emitted from the opening of the groove 13 at different light emission angles.

[0080] Furthermore, since the cross-sectional shape of the groove 13 is non-linear, the groove 13 has a larger sidewall area, so that although the forward light-emitting area equivalent to the width of the groove 13 is lost, a larger lateral light-emitting area is obtained, thereby increasing the total light-emitting area, thereby improving the luminous efficiency of the light-emitting diode; and the curved groove 13 can provide more light-emitting angles, thereby improving the radiation compound luminous efficiency; and since the groove 13 greatly increases the sidewall area of ​​the epitaxial layer 12, the heat dissipation area is increased, the heat dissipation effect of the light-emitting diode in the working state is improved, the energy loss is reduced, and the photoelectric efficiency is improved.

[0081] From the above content, it can be known that the light-emitting diode of the utility model includes: a substrate; an epitaxial layer, including a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked on the substrate in sequence, the first semiconductor layer and the second semiconductor layer have opposite doping types, a groove is formed in the epitaxial layer, the groove at least extends to a part of the second semiconductor layer, and the cross-sectional shape of the groove is non-linear; a first electrode is located on the second semiconductor layer; a second electrode is located on the surface of the substrate away from the epitaxial layer. The utility model can improve the luminous efficiency of the light-emitting diode.

[0082] The above description is only a description of the preferred embodiment of the utility model, and is not any limitation on the scope of the utility model. Any changes and modifications made by ordinary technicians in the field of the utility model based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A light emitting diode, characterized in that: include: substrate; An epitaxial layer, comprising a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer stacked in sequence on the substrate, wherein the first semiconductor layer and the second semiconductor layer have opposite doping types, a groove is formed in the epitaxial layer, the groove extends into at least a portion of the second semiconductor layer, and the cross-sectional shape of the groove is non-straight line; A first electrode, located on the second semiconductor layer; The second electrode is located on a surface of the substrate away from the epitaxial layer.

2. The light emitting diode according to claim 1, characterized in that The trench penetrates the epitaxial layer.

3. The light emitting diode according to claim 1, characterized in that The cross-sectional shape of the groove is a fold line or a wavy line or a combination of a fold line and a wavy line.

4. The light emitting diode according to claim 1, characterized in that The width of the groove is 5 μm to 100 μm.

5. The light emitting diode according to claim 1, characterized in that: The light emitting diode further comprises: An extended electrode is located on the second semiconductor layer, the extended electrode is electrically connected to the first electrode, and the groove is located between two adjacent extended electrodes.

6. The light emitting diode according to claim 5, characterized in that The groove is located in the middle between two adjacent extended electrodes.

7. The light emitting diode according to claim 6, characterized in that The distance between the groove and the extended electrodes on both sides of the groove is 1 / 3 of the distance between two adjacent extended electrodes.

8. The light emitting diode according to claim 5, characterized in that The extended electrode comprises: A plurality of first parts, wherein the first parts extend in a first direction, and the first parts are arranged in sequence in a second direction, and the groove is located between two adjacent first parts; The second portion extends in a second direction and is electrically connected to the first portion.

9. The light emitting diode according to claim 5, characterized in that: One end of the extended electrode is connected to the first electrode, and the other end of the extended electrode extends in a direction away from the first electrode.

10. The light emitting diode according to claim 1, characterized in that The light emitting diode further comprises: A protection layer is located on the side walls of the substrate and the epitaxial layer and on the inner wall of the trench.

11. The light emitting diode according to claim 10, characterized in that The thickness of the protective layer is 0.1 μm to 1 μm.

12. The light emitting diode according to claim 1, characterized in that When the doping type of the first semiconductor layer is P type and the doping type of the second semiconductor layer is N type, the light emitting diode further includes: a reflector layer, located between the first semiconductor layer and the substrate; A bonding layer is located between the reflector layer and the substrate.

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