Light-emitting diode and horizontal light-emitting device

Abstract

The invention relates to a light-emitting diode and a horizontal light-emitting device. The light-emitting diode comprises a light-emitting layer, an upper electrode, a lower electrode, a first semiconductor layer, a second semiconductor layer, a third semiconductor layer and a low-refractive-index dielectric layer. Wherein the upper electrode and the lower electrode are respectively arranged on two opposite side edges of the light-emitting layer, the first semiconductor layer is arranged between the light-emitting layer and the upper electrode, the second semiconductor layer is arranged between the light-emitting layer and the lower electrode, the third semiconductor layer is arranged between the second semiconductor layer and the lower electrode, and the low-refractive-index dielectric layer is arranged around the lower electrode. The upper electrode and the lower electrode are arranged in an overlapping mode in the vertical direction, and the electrical property of the first semiconductor layer and the electrical property of the third semiconductor layer are opposite to the electrical property of the second semiconductor layer.

Description

Technical Field

[0001] The present invention relates to a light emitting diode, in particular to a high brightness light emitting diode. Background Art

[0002] Light Emitting Diode (LED) has the advantages of high brightness, small size, low power consumption and long life, and is widely used in lighting or display products. In order to achieve high brightness, LED often uses wafer bonding as a method to improve brightness. Among them, the bottom structure of the epitaxial layer of the wafer-bonded LED has the following characteristics: (1) The bottom structure of the epitaxial layer of the LED has a low refractive index dielectric layer and a reflective metal. Since the lower the refractive index value of the dielectric layer, the more total reflection there will be. Through this dielectric layer and reflective metal, the light emitted by the active light-emitting layer of the LED is reflected upward to achieve the purpose of improving brightness. (2) When observing the contact metal or transparent conductive layer at the bottom of the LED from top to bottom, the current conduction point is usually distributed in a dot or strip shape outside the upper electrode to achieve the current spreading outside the electrode, so that the light generated by the active light-emitting layer is not blocked by the upper electrode, thereby achieving the purpose of high brightness.

[0003] However, the above structure has a disadvantage. When the current diffuses through the active light-emitting layer to emit light, the position where the current is conducted is usually not corresponding to the dielectric layer with a low refractive index, resulting in the main light-emitting position not being able to correspond to the conditions of the optimal reflectivity, which reduces the overall light-emitting efficiency. In addition, in order to improve the effect of current diffusion of the light-emitting diode to improve the light-emitting efficiency, the prior art does not make the distance between the active light-emitting layer and the ohmic contact electrode too large. Generally speaking, the distance between the light-emitting layer and the ohmic contact electrode is not greater than 2 microns. However, too short a distance between the light-emitting layer and the ohmic contact electrode will lead to poor electrical properties of the light-emitting diode element, such as poor antistatic properties and excessive forward voltage.

[0004] U.S. Patent Publication No. 20130221367A1 discloses a light-emitting diode, which has a structure similar to that disclosed in the above-mentioned prior art, in which the metal contact electrode is located outside the upper electrode to spread the current. However, this metal contact electrode has the above-mentioned problem of light absorption and affecting the light extraction of the LED. In order to overcome the above-mentioned problems, the industry urgently needs an innovative light-emitting diode structure and process to improve the brightness, and at the same time improve the related electrical problems such as poor antistatic properties and excessive forward voltage. Summary of the invention

[0005] The main purpose of the present invention is to provide a high-brightness light-emitting diode, which achieves the effect of dispersing current away from electrodes by adjusting the epitaxial structure to avoid electrode shading, improve light extraction efficiency, and thereby improve the poor electrical properties of existing light-emitting diode structures such as poor antistatic properties and excessive forward voltage.

[0006] To achieve the above-mentioned purpose, the present invention provides a light-emitting diode, comprising: a light-emitting layer, an upper electrode and a lower electrode, a first semiconductor layer, a second semiconductor layer, a third semiconductor layer and a low-refractive-index dielectric layer. The upper electrode and the lower electrode are respectively arranged on two opposite sides of the light-emitting layer, the first semiconductor layer is arranged between the light-emitting layer and the upper electrode, the second semiconductor layer is arranged between the light-emitting layer and the lower electrode, the third semiconductor layer is arranged between the second semiconductor layer and the lower electrode, and the low-refractive-index dielectric layer is arranged around the lower electrode. The upper electrode and the lower electrode are arranged overlappingly at upper and lower positions, and the electrical properties of the first semiconductor layer and the third semiconductor layer are opposite to those of the second semiconductor layer.

[0007] In one embodiment, the light-emitting diode of the present invention further includes a plurality of epitaxial conduction points, which are arranged in the third semiconductor layer corresponding to the position of the low refractive index dielectric layer, so that a current can flow from the upper electrode through the first semiconductor layer, the light-emitting layer, the second semiconductor layer, each epitaxial conduction point, the third semiconductor layer, and into the lower electrode.

[0008] In one embodiment, the epitaxial conduction point of the light-emitting diode of the present invention is a composite layer with an extremely heavily doped tunneling effect. The tunneling effect of semiconductor physics is applied to form a tunneling effect from the N-type semiconductor to the P-type semiconductor when the N-type semiconductor and the P-type semiconductor are extremely heavily doped, thereby achieving the effect of dispersing the current away from the electrode.

[0009] In one embodiment, the light emitting diode of the present invention further comprises a current blocking layer, which is disposed in the second semiconductor layer corresponding to the positions of the upper electrode and the lower electrode, so as to prevent conduction between the upper electrode and the lower electrode, thereby achieving the effect of dispersing the current away from the electrodes.

[0010] In one embodiment, the current blocking layer of the light emitting diode of the present invention is formed by destroying a portion of the second semiconductor layer between the upper electrode and the lower electrode by etching.

[0011] In one embodiment, the light emitting diode of the present invention further comprises a reflective metal layer, and the reflective metal layer is electrically connected to the lower electrode.

[0012] In one embodiment, the reflective metal layer of the light emitting diode of the present invention is selected from the group consisting of gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), zinc gold (ZnAu) or a combination thereof.

[0013] In one embodiment, the low refractive index dielectric layer of the light emitting diode of the present invention is selected from the group consisting of silicon dioxide (SiO2), silicon nitride (Si3N4), indium tin oxide (ITO), magnesium fluoride (MgF2) or a combination thereof.

[0014] To achieve the above-mentioned purpose, the present invention further provides a horizontal light-emitting device, comprising the light-emitting diode as described above, a bonding metal layer and an external electrode, wherein the bonding metal layer extends horizontally outward from the first semiconductor layer, the light-emitting layer, the second semiconductor layer and the third semiconductor layer, one end of which is electrically connected to the lower electrode, and the other end of which is electrically connected to the external electrode.

[0015] In one embodiment, the horizontal light emitting device of the present invention further includes an insulating substrate, and the insulating substrate is connected to the bonding metal layer.

[0016] After referring to the accompanying drawings and the specific embodiments described below, a person skilled in the art will be able to understand other objectives of the present invention, as well as the technical means and embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figures 1 to 10 A diagram showing the steps of manufacturing a light emitting diode according to an embodiment of the present invention;

[0018] Fig.11 It is a top view of a light emitting diode structure in one embodiment of the present invention;

[0019] Figure 12 to Figure 16 A diagram showing the steps of manufacturing a light emitting diode according to another embodiment of the present invention; and

[0020] Fig.17 FIG. 4 is a schematic diagram of a horizontal light emitting device according to an embodiment of the present invention.

[0021] Description of reference numerals:

[0022] 10, 20 light emitting diodes

[0023] 30 Horizontal lighting device

[0024] 100, 200 substrate

[0025] 110, 210 first semiconductor layer

[0026] 120, 220 luminous layer

[0027] 130, 230 second semiconductor layer

[0028] 140 Composite Layer

[0029] 140a Epitaxial conduction point

[0030] 142 P-type epitaxial layer

[0031] 144 N-type epitaxial layer

[0032] 150, 250 Third semiconductor layer

[0033] 160, 260 dielectric layer

[0034] 170, 270 lower electrode

[0035] 172 Back Electrode

[0036] 174 External Electrode

[0037] 180, 280 reflective metal layer

[0038] 182, 282 Bonding metal layer

[0039] 184, 284 Permanently bonded substrate

[0040] 190, 290 upper electrode

[0041] 240 Depression area. DETAILED DESCRIPTION

[0042] The present invention will be explained below by way of examples, and the examples of the present invention are not intended to limit the present invention to any specific environment, application or special method as described in the examples. Therefore, the description of the examples is only for the purpose of illustrating the present invention, and is not intended to limit the present invention. It should be noted that in the following examples and drawings, elements not directly related to the present invention have been omitted and not shown, and the dimensional relationship between the elements in the drawings is only for easy understanding, and is not intended to limit the actual proportion.

[0043] Please refer to Figure 1, which discloses one embodiment of the present invention for making a light-emitting diode, using a gallium arsenide (GaAs) 100 as a growth substrate, but is not limited thereto. Subsequently, an aluminum gallium indium arsenide (AlGaInAs) double heterostructure is formed on the gallium arsenide substrate. Specifically, in this embodiment, the double heterostructure includes an N-type first semiconductor layer 110, a light-emitting layer 120 formed on the first semiconductor layer 110, and a P-type second semiconductor layer 130 formed on the light-emitting layer 120. Among them, the light-emitting layer 120 is formed by a multiple quantum well (MQW) structure, which includes aluminum gallium arsenide (AlGaAs) as a barrier layer of the multiple quantum well, and indium gallium arsenide (InGaAs) as a well layer of the multiple quantum well. In addition, the N-type first semiconductor layer 110 is a silicon (Si) doped aluminum gallium arsenide (AlGaAs) cladding layer, and the P-type second semiconductor layer 130 is a carbon (C) doped aluminum gallium arsenide (AlGaAs) cladding layer. It should be noted that the material described in the above embodiment is only one embodiment, and the present invention is not limited thereto. In practical applications, the material and its composition can be adjusted according to the light emission wavelength. For example, the epitaxial layer can be aluminum gallium indium phosphide (AlGaInP), indium gallium phosphide (InGaP), aluminum gallium arsenide (AlGaAs), indium gallium arsenide (InGaAs), indium phosphide (InP), etc.

[0044] Please continue reading Figure 1 , a heavily doped composite layer 140 with tunneling effect is formed on the P-type second semiconductor layer 130, and the heavily doped composite layer 140 with tunneling effect includes a P-type epitaxial layer 142 and an N-type epitaxial layer 144. Among them, the P-type epitaxial layer 142 can be a gallium arsenide (GaAs) epitaxial layer doped with extremely heavy carbon (C), and the N-type epitaxial layer 144 can be a gallium arsenide (GaAs) epitaxial layer doped with extremely heavy tellurium (Te). After the extremely heavily doped composite layer 140 with tunneling effect is formed on the P-type second semiconductor layer 130, a yellow light etching process is performed to pattern the extremely heavily doped composite layer 140, so that when the patterned extremely heavily doped composite layer 140 is operated in the subsequent light-emitting diode, a plurality of epitaxial conduction points 140a are formed due to the tunneling effect generated between the N-type semiconductor and the P-type semiconductor, thereby achieving the effect of dispersing the current, such as Figure 2 shown.

[0045] Next, see Figure 3 As shown, epitaxial growth and doping processes are performed again to form an N-type third semiconductor layer 150. The third semiconductor layer 150 will fill the patterned heavily doped composite layer 140 and continue to cover the entire second semiconductor layer 130 to a considerable thickness. In a specific embodiment, the third semiconductor layer 150 can be a silicon-doped gallium arsenide (GaAs) epitaxial layer.

[0046] like Figure 4 As shown, a dielectric layer 160 is formed on the third semiconductor layer 150. Specifically, the dielectric layer 160 is a low refractive index dielectric layer, and its material can be selected from the group consisting of silicon dioxide (SiO2), silicon nitride (Si3N4), indium tin oxide (ITO), magnesium fluoride (MgF2) or a combination thereof. Then, the low refractive index dielectric layer 160 is subjected to a patterning etching process to locate the subsequent lower electrode position, such as Figure 5 It should be emphasized that the patterned dielectric layer 160 in this step will vertically cover the patterned heavily doped composite layer 140, that is, cover the plurality of epitaxial conductive points 140a.

[0047] See also Figure 6 , followed by a metal plating process to form a lower electrode 170, which will be filled with Figure 5 The recessed area in the dielectric layer 160 removed by the etching process is shown, so that the lower electrode 170 is surrounded by the patterned low refractive index dielectric layer 160, and the lower electrode 170 is a P-type electrode used as an ohmic contact metal. As mentioned above, the position and pattern structure of the lower electrode 170 are defined by the dielectric layer 160, so that in the vertical position, the lower electrode 170 and the plurality of epitaxial conductive points 140a do not overlap.

[0048] See also Figure 7 After forming the lower electrode 170, the metal plating process can be continued to form a reflective metal layer 180, which covers the low refractive index dielectric layer 160 and the lower electrode 170 and forms an electrical connection between the lower electrode 170. In practical applications, the lower electrode 170 and the reflective metal layer 180 can use the same conductive material. Generally speaking, one of the groups consisting of gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), zinc gold (ZnAu) or a combination thereof can be selected. The reflective metal layer 180, in combination with the aforementioned low refractive index dielectric layer 160, can improve the reflection efficiency of the light emitted downward from the light-emitting layer 120.

[0049] See also Figure 8 A bonding metal layer 182 for subsequent bonding with a permanent bonding substrate is formed by evaporation above the lower electrode 170 and the reflective metal layer 180. Similarly, the bonding metal layer 182 is also evaporated on the permanent bonding substrate 184. The bonding metal material can be gold (Au) or indium gold (InAu) alloy, and the permanent bonding substrate 184 can be, but is not limited to, a silicon substrate or a sapphire substrate. Next, the light emitting diode structure on the epitaxial substrate 100 is metal-bonded to the permanent bonding substrate 184 through the bonding metal layer 182.

[0050] See also Fig. 9 , remove the GaAs epitaxial substrate 100 to expose the first semiconductor layer 110, and flip it over so that the permanent bonding substrate 184 is located at the bottom of the light emitting diode structure. Fig.10 , a MESA process is performed to etch a portion of the epitaxial composite layer to form a cutting path on the bonding substrate 184, and a patterned upper electrode 190 is formed on the first semiconductor layer 110. The upper electrode 190 is an N-type electrode with opposite electrical properties to the lower electrode 170. The material of the upper electrode 190 can be selected from one of the groups consisting of germanium (Ge), titanium (Ti), platinum (Pt), and gold (Au) or a combination thereof. In particular, the upper electrode 190 and the lower electrode 170 are overlapped at the upper and lower vertical positions, and the pattern structures of the upper electrode 190 and the lower electrode 170 are substantially the same. Then, a back electrode 172 is formed on the other side of the permanent bonding substrate 184 to be electrically connected to the lower electrode 170, and the final structure of the light-emitting diode 10 of the present invention is completed.

[0051] In the above structure, please refer to Fig.10 and Fig.11 ,in, Fig.11 So Fig.10 , which shows a plurality of epitaxial conductive points 140a, a low refractive index dielectric layer 160, an upper electrode 190, and a lower electrode 170 (such as Fig.11Since the third semiconductor layer 150 of the light-emitting diode 10 of the present invention is provided with a plurality of epitaxial conduction points 140a using the tunneling effect, the tunneling effect generated between the N-type epitaxial layer 144 and the P-type epitaxial layer 142 can be used to allow the injected current to flow from the upper electrode 190 through the first semiconductor layer 110, the light-emitting layer 120, and the second semiconductor layer 130, and then be guided and dispersed by each of the epitaxial conduction points 140a, and then flow into the third semiconductor layer 150 and the lower electrode 170, thereby achieving the light-emitting diode structure of the present invention using a plurality of epitaxial conduction points 1 The effect of current diffusion generated by the epitaxial conductive point 140a is more particularly that each epitaxial conductive point 140a overlaps with the low refractive index dielectric layer 160 in a vertical position. Therefore, when the injected current diffuses through the light-emitting layer to the epitaxial conductive point 140a and lights up, the low refractive index dielectric layer overlapping with the epitaxial conductive point 140a at each position can reflect most of the light emitted downward from the light-emitting layer through the low refractive index dielectric layer in a manner with the best reflection efficiency, and will not be shielded by the upper electrode 190, thereby improving the light extraction efficiency of the light-emitting diode. In addition, it should be noted that since the first semiconductor layer 110 and the third semiconductor layer 150 are both N-type and have opposite electrical properties to the P-type second semiconductor layer 130, the P-type second semiconductor layer 130 and the N-type third semiconductor layer 150 have the effect of a reverse diode, which can ensure that the upper electrode 190 and the lower electrode 170 will not be conductive and affect the light extraction efficiency.

[0052] In a preferred embodiment, the thickness of the third semiconductor layer 150 is at least 2 microns, and even reaches 8 microns. The thickened third semiconductor layer 150 can increase the distance between the light-emitting layer 120 and the lower electrode 170 in the complete structure of the light-emitting diode, so as to increase the antistatic ability of the light-emitting diode, thereby overcoming the shortcomings of the existing light-emitting diode structure that the short distance between the light-emitting layer and the lower electrode causes a current crowding effect and reduces the antistatic ability of the light-emitting diode.

[0053] In addition to the above disclosed embodiment, another embodiment of the light emitting diode of the present invention will be described below. Fig.12 , similar to the previous embodiment, a gallium arsenide 200 is also used as a growth substrate, and an AlGaInAs double heterostructure is formed on the gallium arsenide substrate, which includes an N-type first semiconductor layer 210, a light-emitting layer 220 and a P-type second semiconductor layer 230, wherein the light-emitting layer 220 is formed on the first semiconductor layer 210, and the P-type second semiconductor layer 230 is formed on the light-emitting layer 220. The material compositions of the light-emitting layer 220, the first semiconductor layer 210, and the second semiconductor layer 230 are the same as those of the previous embodiment, and the aforementioned contents may be referred to, and no further description is given here.

[0054] See also Fig.13As shown, a patterning process is performed on the P-type second semiconductor layer 230, for example, a yellow light wet etching process is used to remove part of the P-type second semiconductor layer 230 to form a patterned recessed area 240 until the surface of the light-emitting layer 220 is partially exposed. Then, epitaxial growth and doping processes are performed again to form an N-type third semiconductor layer 250. Among them, this third semiconductor layer 250 will fill the patterned recessed area 240 formed by the above-mentioned patterning process, and continue to cover the entire second semiconductor layer 230 to a considerable thickness. In a specific embodiment, the third semiconductor layer 250 can be a silicon-doped gallium arsenide epitaxial layer. In a preferred embodiment, the thickness of the third semiconductor layer 250 is at least 2 microns, and can even reach 8 microns.

[0055] like Fig.14 As shown, a dielectric layer 260 is formed on the third semiconductor layer 250. Specifically, the dielectric layer 260 is a low refractive index dielectric layer, and its material can be selected from one of the group consisting of silicon dioxide, silicon nitride, indium tin oxide, and magnesium fluoride, or a combination thereof. Then, the low refractive index dielectric layer 260 is subjected to a patterning etching process to locate the position of the lower electrode 270. Subsequently, a metal plating process is performed to form the lower electrode 270, which is surrounded by the low refractive index dielectric layer 260, and the lower electrode 270 is a P-type electrode, which is used as an ohmic contact metal. It should be noted that the position and pattern structure of the lower electrode 270 are positioned by the patterning process of the dielectric layer 260. When patterning the dielectric layer 260, the position and pattern structure of the lower electrode 270 to be formed subsequently must be relatively arranged at the vertical position of the recessed area 240 in the third semiconductor layer 250, so that the pattern structures of the lower electrode 270 and the recessed area 240 are roughly the same.

[0056] See also Fig.15 After forming the lower electrode 270, a metal plating process may be continuously performed to form a reflective metal layer 280, which covers the low refractive index dielectric layer 260 and the lower electrode 270 and forms an electrical connection between the lower electrode 270. In practical applications, the lower electrode 270 and the reflective metal layer 280 may use the same conductive material, which may be selected from the group consisting of gold, silver, aluminum, beryllium gold, zinc gold, or a combination thereof.

[0057] The subsequent process is similar to the previous embodiment, please refer to Fig.16, similar to the previous embodiment, a bonding metal layer 282 and a permanent bonding substrate 284 are successively formed on the lower electrode 270 and the reflective metal layer 280, and the epitaxial substrate 200 is removed. Subsequently, a MESA process is performed and a patterned upper electrode 290 is formed on the first semiconductor layer 210 to form the final structure of the light-emitting diode 20 of the second embodiment. The material of the upper electrode 290 can be selected from one of the groups consisting of germanium, titanium, platinum, and gold, or a combination thereof. Similarly, in this embodiment, the upper electrode 290 is relatively disposed above the position of the patterned recessed region 240 in the third semiconductor layer 250, and has substantially the same pattern structure as the recessed region 240 and the lower electrode 270.

[0058] In the aforementioned structure, the recessed area 240 is designed to be aligned with the upper electrode 290 and the lower electrode 270 in a vertical position. Therefore, when the light emitting diode 20 is in normal operation, the recessed area 240 has a good current blocking effect due to the destruction of the epitaxial structure in the etching process, so that the recessed area 240 becomes a current blocking layer to ensure that the current between the upper electrode and the lower electrode will not be conducted, so as to force the injected current to be dispersed outside the recessed area 240, and then dispersed among the entire light emitting diode structure. In conjunction with the low refractive index dielectric layer 260 outside the recessed area 240 and the lower electrode 270, most of the light emitted downward from the light emitting layer is reflected upward through the low refractive index dielectric layer in a manner with optimal reflection efficiency, and will not be shielded by the upper electrode 290, thereby improving the light extraction efficiency of the light emitting diode 20 and improving the brightness of the light emitting diode 20.

[0059] Although the above embodiments use a vertical light emitting diode structure to illustrate the technical features of the present invention, the light emitting diode of the present invention is not limited to the vertical light emitting diode structure. Fig.17 , which specifically shows an embodiment of applying the above-mentioned light-emitting diode structure to a horizontal light-emitting diode structure. Fig.17 A horizontal light emitting device 30 is shown, and its epitaxial structure is substantially the same as the above embodiment, and the only difference is that the bonding metal layer 182 extends horizontally outward from the first semiconductor layer 110, the light emitting layer 120, the second semiconductor layer 130 and the third semiconductor layer 150 relative to other epitaxial layers, one end of which is electrically connected to the lower electrode 170, and the other end of which is electrically connected to an external electrode 174, and the permanent bonding substrate 184 connected to the bonding metal layer 182 is an insulating substrate. The rest of the epitaxial structure can refer to the above content and will not be repeated here.

[0060] The above embodiments are only used to illustrate the embodiments of the present invention and explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily completed by those skilled in the art belong to the scope claimed by the present invention, and the scope of protection of the present invention shall be based on the claims.

Claims

1. A light emitting diode comprising: a luminescent layer; An upper electrode and a lower electrode are respectively disposed on two opposite sides of the light-emitting layer; A first semiconductor layer disposed between the light emitting layer and the upper electrode; A second semiconductor layer is disposed between the light emitting layer and the lower electrode; a third semiconductor layer disposed between the second semiconductor layer and the lower electrode; and a low refractive index dielectric layer disposed around the lower electrode; in, The upper electrode and the lower electrode are overlapped at upper and lower positions, and the electrical properties of the first semiconductor layer and the third semiconductor layer are opposite to the electrical property of the second semiconductor layer.

2. The light emitting diode as described in claim 1 further comprises a plurality of epitaxial conduction points, which are arranged in the third semiconductor layer corresponding to the position of the low refractive index dielectric layer, so that a current can flow from the upper electrode through the first semiconductor layer, the light emitting layer, the second semiconductor layer, each of the epitaxial conduction points, the third semiconductor layer, and into the lower electrode.

3. The light emitting diode according to claim 2, wherein: Each of the epitaxial conductive points is a composite layer with a very heavily doped tunneling effect.

4. The light emitting diode as claimed in claim 1, further comprising a current blocking layer, which is disposed in the second semiconductor layer corresponding to the positions of the upper electrode and the lower electrode, so as to prevent current from being conducted between the upper electrode and the lower electrode.

5. The light emitting diode according to claim 4, wherein: The current blocking layer is formed by destroying a portion of the second semiconductor layer corresponding to the position between the upper electrode and the lower electrode by etching. 6 . The light emitting diode as claimed in claim 1 , further comprising a reflective metal layer, wherein the reflective metal layer is electrically connected to the lower electrode. 7 . The light emitting diode as claimed in claim 6 , wherein the reflective metal layer is selected from the group consisting of gold, silver, aluminum, beryllium gold, zinc gold or a combination thereof. 8 . The light emitting diode as claimed in claim 1 , wherein the low refractive index dielectric layer is selected from the group consisting of silicon dioxide, silicon nitride, indium tin oxide, magnesium fluoride, or a combination thereof.

9. A horizontal light emitting device, comprising: The light-emitting diode according to any one of claims 1 to 8; a bonding metal layer; and an external electrode; in, The bonding metal layer horizontally extends out of the first semiconductor layer, the light emitting layer, the second semiconductor layer and the third semiconductor layer, and one end of the bonding metal layer is electrically connected to the lower electrode, and the other end is electrically connected to the external electrode. 10 . The horizontal light emitting device as claimed in claim 9 , further comprising an insulating substrate, wherein the insulating substrate is connected to the bonding metal layer.

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