Vertical light emitting diode

Abstract

A light emitting diode includes a support substrate, a first conductive type semiconductor layer, an upper insulating layer on the first conductive type semiconductor layer, a mesa including an active layer and a second conductive type semiconductor layer and located below a portion of the first conductive type semiconductor layer to expose an edge of the first conductive type semiconductor layer, the mesa including a second through hole exposing the first conductive type semiconductor layer, a first electrode including a first contact portion electrically connected to the first conductive type semiconductor layer through the first through hole and a second contact portion electrically connected to the first conductive type semiconductor layer through the second through hole, a second electrode electrically connected to the second conductive type semiconductor layer, and at least one upper electrode pad connected to the second electrode, the first through hole being disposed in an area surrounded by the edge of the mesa, a portion of each second through hole being surrounded by the active layer and the second conductive type semiconductor layer and disposed along the edge of the mesa, and the upper insulating layer including a plurality of material layers.

Description

Technical Field

[0001] This invention relates to a light-emitting diode, and more particularly to a vertical light-emitting diode with improved current dispersion performance. Background Technology

[0002] Typically, nitrides of group III elements such as gallium nitride (GaN) and aluminum nitride (AlN) exhibit excellent thermal stability and possess direct transition band structures, making them highly sought-after materials for light sources in the visible and ultraviolet light regions.

[0003] These group III element nitride semiconductor layers are difficult to fabricate into homogeneous substrates suitable for their growth. Therefore, they are grown on heterogeneous substrates with similar crystalline structures using processes such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). Sapphire substrates, which have a hexagonal crystal structure, are primarily used as heterogeneous substrates. However, sapphire is an electrical insulator, thus limiting the structure of light-emitting diodes (LEDs). Therefore, a technique has been developed to grow epitaxial layers, such as nitride semiconductor layers, on heterogeneous substrates like sapphire. After bonding a support substrate to the epitaxial layer, the heterogeneous substrate is separated using techniques such as laser lift-off to fabricate high-efficiency LEDs with vertical structures.

[0004] Typically, compared to conventional horizontal LEDs, vertical LEDs offer superior current dispersion and utilize a support substrate with higher thermal conductivity than sapphire, resulting in excellent heat dissipation. Furthermore, a reflective metal layer is placed between the support substrate and the semiconductor layer to reflect light directed towards the support substrate, thereby improving light extraction efficiency.

[0005] Furthermore, vertically oriented LEDs can improve light extraction efficiency by roughening the surface of the light-emitting epitaxial layer (n-type semiconductor layer). For this purpose, wet etching processes such as photoelectrochemical etching (PEC) are performed on the epitaxial layer. It is necessary to protect the roughened surface of the epitaxial layer from external environmental influences such as moisture. In particular, LEDs emitting short-wavelength ultraviolet light are vulnerable to moisture due to their Al-containing nitride epitaxial layer, such as AlGaN, and therefore require protection.

[0006] Furthermore, vertically oriented light-emitting diodes (LEDs) typically use a conductive support substrate, with an anode electrode pad formed on the support substrate side and a cathode electrode pad formed on the epitaxial layer. To further facilitate current dispersion in the epitaxial layer, an electrode extension extending from the cathode electrode pad and making electrical contact with the epitaxial layer is used. To uniformly disperse the current across a wide area of ​​the epitaxial layer, the electrode extension can be formed not only in the central region of the LED but also near the edges of the epitaxial layer. However, since the cathode electrode pad and the electrode extension are located on the light-emitting epitaxial layer, they block light, thus reducing the luminous efficiency of the LED. Summary of the Invention

[0007] The problem to be solved by the present invention is to provide a new type of vertical light-emitting diode with a novel structure that can distribute current more uniformly across a wide area.

[0008] Another problem to be solved by the present invention is to provide a light-emitting diode with a vertical structure that can prevent moisture from penetrating from the external environment.

[0009] An embodiment of the present invention provides a light-emitting diode (LED) comprising: a support substrate; a first conductive semiconductor layer disposed above the support substrate; an upper insulating layer disposed on the first conductive semiconductor layer; a mesa comprising an active layer and a second conductive semiconductor layer, and disposed below a portion of the first conductive semiconductor layer to expose the edge of the first conductive semiconductor layer, the mesa comprising a first through-hole and a second through-hole exposing the first conductive semiconductor layer through the second conductive semiconductor layer and the active layer; and a first electrode disposed between the second conductive semiconductor layer and the support substrate, and comprising an electrode that contacts the first conductive semiconductor layer through the first through-hole. The upper insulating layer comprises a first contact portion electrically connected to the conductor layer and a second contact portion electrically connected to the first conductive semiconductor layer through the second through-hole; a second electrode disposed between the first electrode and the second conductive semiconductor layer and electrically connected to the second conductive semiconductor layer; and at least one upper electrode pad adjacent to the first conductive semiconductor layer and connected to the second electrode, the first through-hole being surrounded by the active layer and the second conductive semiconductor layer and disposed in a region surrounded by the edge of the mesa, a portion of each of the second through-holes being surrounded by the active layer and the second conductive semiconductor layer and disposed along the edge of the mesa, and the upper insulating layer comprising a plurality of material layers.

[0010] According to one embodiment of the present invention, current can be uniformly distributed across the entire area of ​​the mesa by a first contact portion formed within a first through hole arranged along the edge of the mesa. Furthermore, the upper insulating layer is formed of multiple material layers, thereby preventing damage to the nitride semiconductor layer by external environments such as moisture, and improving the reliability of the light-emitting diode.

[0011] The features and advantages of the present invention will become clearer from the following detailed description. Attached Figure Description

[0012] Figure 1 This is a top view illustrating a light-emitting diode according to an embodiment of the present invention.

[0013] Figure 2 It is along Figure 1 The cross-sectional view of the section cut by the intercepting line AA.

[0014] Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 5a , Figure 5b , Figure 6a , Figure 6b , Figure 7a as well as Figure 7b These are top views and cross-sectional views illustrating a method for manufacturing a light-emitting diode according to an embodiment of the present invention.

[0015] Figure 8 This is a schematic top view illustrating a light-emitting diode according to another embodiment of the present invention.

[0016] Figure 9 This is an image showing the light emission pattern of a conventional light-emitting diode and a light-emitting diode according to an embodiment of the present invention.

[0017] Figure 10 This is an exploded perspective view illustrating a lighting device using a light-emitting diode according to an embodiment of the present invention.

[0018] Figure 11 This is a cross-sectional view illustrating a display device using a light-emitting diode to which another embodiment of the present invention is applied.

[0019] Figure 12 This is a cross-sectional view illustrating a display device using a light-emitting diode to which another embodiment of the present invention is applied.

[0020] Figure 13 This is a cross-sectional view illustrating an example of a light-emitting diode to which another embodiment of the present invention is applied in a headlamp. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are provided as examples to fully convey the concept of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, and may be embodied in other forms. Moreover, in the drawings, the same reference numerals denote the same constituent elements, and for convenience, the width, length, thickness, etc., of the constituent elements are sometimes exaggerated.

[0022] An embodiment of the present invention provides a light-emitting diode (LED) comprising: a support substrate; a first conductive semiconductor layer disposed above the support substrate; an upper insulating layer disposed on the first conductive semiconductor layer; a mesa comprising an active layer and a second conductive semiconductor layer, and disposed below a portion of the first conductive semiconductor layer to expose the edge of the first conductive semiconductor layer, the mesa comprising a first through-hole and a second through-hole exposing the first conductive semiconductor layer through the second conductive semiconductor layer and the active layer; and a first electrode disposed between the second conductive semiconductor layer and the support substrate, and comprising an electrode that contacts the first conductive semiconductor layer through the first through-hole. The upper insulating layer comprises a first contact portion electrically connected to the conductor layer and a second contact portion electrically connected to the first conductive semiconductor layer through the second through-hole; a second electrode disposed between the first electrode and the second conductive semiconductor layer and electrically connected to the second conductive semiconductor layer; and at least one upper electrode pad adjacent to the first conductive semiconductor layer and connected to the second electrode, the first through-hole being surrounded by the active layer and the second conductive semiconductor layer and disposed in a region surrounded by the edge of the mesa, a portion of each of the second through-holes being surrounded by the active layer and the second conductive semiconductor layer and disposed along the edge of the mesa, and the upper insulating layer comprising a plurality of material layers.

[0023] The first conductive semiconductor layer may have a rough surface. In one embodiment, the upper insulating layer may include: a first layer covering the rough surface of the first conductive semiconductor layer; a second layer covering the first layer and having a higher refractive index than the first layer; and a third layer covering the second layer and having a lower refractive index than the second layer. For example, the first and third layers may contain SiO2, and the second layer may contain Al2O3. Furthermore, the first layer may be thicker than the second and third layers. The upper insulating layer may include an Al2O3 layer covering the rough surface of the first conductive semiconductor layer and a SiO2 layer covering the Al2O3 layer.

[0024] Alternatively, the first conductive semiconductor layer may include an Al-containing nitride semiconductor layer.

[0025] The support substrate may have a rectangular shape. In one embodiment, the upper electrode pad may be arranged elongated along one side edge of the support substrate between one side edge of the mesa and one side edge of the support substrate. Furthermore, a portion of the second through-hole may be disposed between the upper electrode pad and the mesa.

[0026] In another embodiment, the two upper electrode pads may be arranged near the two corners along one side edge of the support substrate. Furthermore, a portion of the mesa may be located between the two upper electrode pads, and a portion of the second through-hole may be formed in this portion of the mesa located between the two upper electrode pads.

[0027] Alternatively, the second through holes may be arranged adjacent to the four edges of the support substrate.

[0028] Alternatively, the light-emitting diode may have a mirror-symmetrical structure. This allows the current to be distributed symmetrically.

[0029] Alternatively, the light-emitting diode may further include: a first insulating layer that insulates the first electrode from the first conductive semiconductor layer; and a second insulating layer located between the first electrode and the second electrode. Furthermore, the light-emitting diode may further include: a reflective layer located between the second insulating layer and the first electrode. Additionally, the reflective layer may include a distributed Bragg reflector.

[0030] Alternatively, the light-emitting diode may further include: a welding metal layer between the first electrode and the support substrate; and a first electrode protection metal layer between the welding metal layer and the first electrode to cover the first electrode.

[0031] The second electrode may include: an ohmic reflective layer in ohmic contact with the second conductive semiconductor layer; and a protective metal layer protecting the ohmic reflective layer. Furthermore, the protective metal layer may extend outward from the first conductive semiconductor layer, and the upper electrode pad may be connected to the protective metal layer. In one embodiment, the upper electrode pad may be connected to the protective metal layer through the upper insulating layer and the first insulating layer.

[0032] Alternatively, the light-emitting diode may further include a second insulating layer between the first electrode and the second electrode, the second insulating layer covering the side of the protective metal layer.

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic top view illustrating a light-emitting diode according to an embodiment of the present invention. Figure 2 It is along Figure 1 The cross-sectional view of the section cut by the intercepting line AA.

[0035] Reference Figure 1 as well as Figure 2The light-emitting diode 100 includes: a support substrate 51, a semiconductor stacked structure 30, a first insulating layer 31, a second insulating layer 37, a first electrode 39, a second electrode 34, a first electrode protective metal layer 41, a welding metal layer 45, an upper insulating layer 53, and an upper electrode pad 55. The semiconductor stacked structure 30 may include a first conductive semiconductor layer 25, an active layer 27, and a second conductive semiconductor layer 29. The second electrode 34 may include an ohmic reflective layer 33 and a protective metal layer 35.

[0036] The support substrate 51 differs from the growth substrate used to grow the compound semiconductor layer; it is a secondary substrate attached to the already grown compound semiconductor layer. The support substrate 51 can be a conductive substrate, such as a metal substrate or a semiconductor substrate, but is not limited to these; it can be an insulating substrate such as sapphire. The support substrate 51 can be generally rectangular, especially square.

[0037] The semiconductor stack structure 30 is located on the support substrate 51 and includes a second conductivity semiconductor layer 29, an active layer 27, and a first conductivity semiconductor layer 25. The second conductivity semiconductor layer 29 may be a p-type nitride semiconductor layer, and the first conductivity semiconductor layer 25 may be an n-type nitride semiconductor layer, but these are not necessarily limited to these, and vice versa. The semiconductor stack structure 30 is located on a portion of the support substrate 51. That is, compared to the semiconductor stack structure 30, the support substrate 51 has a relatively wide area, and the semiconductor stack structure 30 is located in a region surrounded by the edge of the support substrate 51.

[0038] The first conductive semiconductor layer 25, the active layer 27, and the second conductive semiconductor layer 29 can be formed of III-N series compound semiconductors, such as (Al, Ga, In)N semiconductors. The first conductive semiconductor layer 25 and the second conductive semiconductor layer 29 can each be a single layer or multiple layers. For example, the first conductive semiconductor layer 25 and / or the second conductive semiconductor layer 29 may include a contact layer and a cladding layer, and may also include a superlattice layer. Additionally, a rough surface R can be formed on the top surface of the first conductive semiconductor layer 25. On the other hand, the active layer 27 can be a single quantum well structure or a multiple quantum well structure. In one embodiment, the active layer can be configured to emit ultraviolet light, and the first conductive semiconductor layer may include an Al-containing nitride semiconductor layer such as AlGaN or AlInGaN.

[0039] On the other hand, the semiconductor stack structure 30 may include a mesa M disposed beneath the first conductive semiconductor layer 25. The mesa M includes a second conductive semiconductor layer 29 and an active layer 27, and is located beneath a portion of the first conductive semiconductor layer 25. Thus, the lower surface of the first conductive semiconductor layer 25 is exposed around the mesa M. The mesa M also has a first through-hole 32a and a second through-hole 32b that penetrate the second conductive semiconductor layer 29 and the active layer 27 to expose the first conductive semiconductor layer 25.

[0040] The first through-hole 32a is disposed in the region surrounded by the edge of the mesa M. The first through-hole 32a is surrounded by the active layer 27 and the second conductive semiconductor layer 29, respectively. The first through-holes 32a can be arranged at approximately a certain interval and are separated from the edge of the mesa M.

[0041] A portion of each second through-hole 32b is surrounded by an active layer 27 and a second conductive semiconductor layer 29. The second through-holes 32b are arranged along the edge of the mesa M, and the first conductive semiconductor layer 25 exposed through the second through-holes 32b is connected to the first conductive semiconductor layer 27 exposed around the mesa M.

[0042] The second through hole 32b is recessed from the edge of the platform M towards the inside of the platform M. This ensures the light-emitting area between adjacent second through holes 32b, thus reducing the reduction in the light-emitting area.

[0043] like Figure 4a As shown, the second through hole 32b can be arranged on each of the four edges of the platform M, so that the current can be evenly distributed even in the edge region of the platform M.

[0044] On the other hand, the spacing between adjacent second through holes 32b can also be constant, but is not necessarily limited to this. For example, the spacing between adjacent second through holes 32b can vary depending on the arrangement of the upper electrode pads 55. In one embodiment, the spacing between second through holes 32b arranged in the region between the upper electrode pads 55 can be smaller than the spacing between first through holes 32a.

[0045] In addition, the interval between the first through hole 32a and the second through hole 32b can be the same or greater than the interval between the first through holes 32a.

[0046] The first insulating layer 31 is located between the semiconductor stack structure 30 and the support substrate 51, and covers the first conductive semiconductor layer 25 exposed around the mesa M and the first conductive semiconductor layer 25 exposed in the first through hole 32a and the second through hole 32b. The first insulating layer 31 may also cover the side surface of the mesa M and a portion of the bottom surface of the mesa M. In addition, the first insulating layer 31 may extend to the outside of the semiconductor stack structure 30. However, the first insulating layer 31 has openings in the first through hole 32a and the second through hole 32b to expose the first conductive semiconductor layer 25 so that the first electrode 39 is connected to the first conductive semiconductor layer 25, and also has an opening to expose the bottom surface of the mesa M so that the second electrode 34 is connected to the second conductive semiconductor layer 29.

[0047] The first insulating layer 31 can be a single layer or multiple layers of silicon oxide film or silicon nitride film, or it can be a distributed Bragg reflector obtained by repeatedly stacking insulating layers with different refractive indices, such as SiO2 / TiO2 or SiO2 / Nb2O5.

[0048] The ohmic reflective layer 33 makes ohmic contact with the second conductive semiconductor layer 29 exposed through the trench of the first insulating layer 31. The ohmic reflective layer 33 may be connected to the first insulating layer 31, but as shown, the edges of the ohmic reflective layer 33 may be spaced apart from the first insulating layer 31. The ohmic reflective layer 33 may include a reflective layer such as Ag, or a metal layer such as Ni for ohmic contact. The ohmic reflective layer 33 defines and exists in the region below the mesa M.

[0049] On the other hand, the protective metal layer 35 is located between the ohmic reflective layer 33 and the support substrate 51, and covers the ohmic reflective layer 33. The protective metal layer 35 can contact the second conductive semiconductor layer 29 exposed between the ohmic reflective layer 33 and the first insulating layer 31. The protective metal layer 35 also covers the first insulating layer 31 and extends outward into the region below the semiconductor stack structure 30. The protective metal layer 35 exposes the first insulating layer 31 beneath the first through-hole 32a and the second through-hole 32b of the mesa M.

[0050] The protective metal layer 35 prevents the movement of metallic materials, such as Ag, from the ohmic reflective layer 33, while also preventing the sides of the ohmic reflective layer 33 from being exposed to the outside. The protective metal layer 35 may, for example, include Pt, Ni, Ti, W, Au, or alloys thereof.

[0051] The second insulating layer 37 covers the protective metal layer 35 below it. The second insulating layer 37 may cover the entire bottom surface of the protective metal layer 35. Furthermore, the second insulating layer 37 may cover the sides of the protective metal layer 35 to prevent the sides of the protective metal layer 35 from being exposed to the outside.

[0052] The second insulating layer 37 can be a single layer or multiple layers of silicon oxide film or silicon nitride film, or it can be a distributed Bragg reflector obtained by repeatedly stacking insulating layers with different refractive indices, such as SiO2 / TiO2 or SiO2 / Nb2O5.

[0053] On the other hand, the first electrode 39 is located between the second insulating layer 37 and the support substrate 51, and is electrically connected to the first conductive semiconductor layer 25 through the first insulating layer 31 and the second insulating layer 37. The first electrode 39 is arranged between the second electrode 34 and the support substrate 51.

[0054] The first electrode 39 has a first contact portion 39a that communicates with the first conductive semiconductor layer 25 within a first through hole 32a, and a second contact portion 39b that communicates with the first conductive semiconductor layer 25 within a second through hole 32b. The first contact portion 39a and the second contact portion 39b are insulated from the mesa M by a first insulating layer 31 and a second insulating layer 37.

[0055] The first electrode 39 may include an ohmic layer in ohmic contact with the first conductive semiconductor layer 25, and may also include a reflective metal layer. For example, the first electrode 39 may include Cr / Al, and may further include Ti / Ni.

[0056] On the other hand, the first electrode protective metal layer 41 can cover the bottom surface of the first electrode 39. The first electrode protective metal layer 41 prevents metallic substances such as Sn from diffusing from the solder metal layer 45 and protects the first electrode 39. The first electrode protective metal layer 41 may include, for example, Au, and may also include Ti and Ni. The first electrode protective metal layer 41 can be formed, for example, by repeatedly stacking Ti / Ni followed by stacking Au.

[0057] On the other hand, the support substrate 51 can be soldered onto the first electrode protection metal layer 41 via a solder metal layer 45. The solder metal layer 45 can be formed, for example, using AuSn or NiSn. Conversely, the support substrate 51 can also be formed on the first electrode protection metal layer 41 using a plating technique. When the support substrate 51 is a conductive substrate, it can function as a lower electrode pad. Conversely, when the support substrate 51 is an insulating substrate, a lower electrode pad can be formed on the first electrode 39 or the first electrode protection metal layer 41 located on the support substrate 51.

[0058] The upper insulating layer 53 may cover the semiconductor stack structure 30, particularly the top and side surfaces of the first conductive semiconductor layer 25. The upper insulating layer 53 may cover the rough surface R and be formed along the unevenness of the rough surface R.

[0059] The upper insulating layer 53 may have a structure consisting of multiple layers of material. (See reference...) Figure 2The enlarged portion shown in the cross-sectional view indicates that the upper insulating layer 53 may include a first layer 53a covering the rough surface R of the first conductive semiconductor layer 25, a second layer 53b covering the first layer 53a, and a third layer 53c covering the second layer 53b.

[0060] In one embodiment, the first layer 53a covering the rough surface R of the first conductive semiconductor layer 25 may contain SiO2. The second layer 53b may contain Al2O3, and the third layer 53c may contain SiO2. The first layer 53a may be formed to be thicker than the second layer 53b and the third layer 53c. The second layer 53b may be the same thickness as or thinner than the third layer 53c. For example, the first layer 53a may be formed with a thickness of 400 nm, and the second layer 53b and the third layer 53c may be formed with a thickness of approximately 60 nm.

[0061] The upper insulating layer 53 can be formed of multiple material layers to prevent moisture from penetrating into the light-emitting diode from the outside. In particular, Al2O3 can be used to prevent moisture from damaging the nitride semiconductor layer. Especially in the case of a light-emitting diode that emits ultraviolet light, the first conductive semiconductor layer 25 may include an Al-containing nitride semiconductor layer, which is vulnerable to moisture penetration. Therefore, the reliability of the light-emitting diode can be improved by using an upper insulating layer 53 containing Al2O3.

[0062] Furthermore, the light uniformity can be improved by controlling the refractive index of the first conductive semiconductor layer 25, the first layer 53a, the second layer 53b, and the third layer 53c.

[0063] As an example, the first conductive semiconductor layer 25 has a refractive index of approximately 2.4, SiO2 has a refractive index of approximately 1.54, and Al2O3 has a refractive index of approximately 1.77. The refractive index of the first conductive semiconductor layer 25 is greater than that of the first layer 53a, resulting in total internal reflection at the interface between the first conductive semiconductor layer 25 and the first layer 53a. Furthermore, the refractive index of the second layer 53b is greater than that of the third layer 53c, resulting in total internal reflection at the interface between the second layer 53b and the third layer 53c.

[0064] On the other hand, light that is totally internally reflected at the interface between the second layer 53b and the third layer 53c can be directed toward the interface between the second layer 53b and the first layer 53a, where at least a portion of the light is totally internally reflected again. As a result, a portion of the light from the second layer 53b toward the third layer 53c is totally internally reflected at the interface between the second layer 53b and the third layer 53c, and a portion of the totally internally reflected light is totally internally reflected again at the interface between the second layer 53b and the first layer 53a, thus allowing horizontal diffusion of light to occur in the second layer 53b.

[0065] The light uniformity of the light-emitting diode can be improved by total internal reflection of light occurring at the interface between the second and third layers 53c and at the interface between the second and first layers. Furthermore, total internal reflection at the interface between the first conductive semiconductor layer 25 and the first layer 53a can also improve the light uniformity of the light-emitting diode in this embodiment.

[0066] In this embodiment, the upper insulating layer 53 is described as including a first layer 53a, a second layer 53b, and a third layer 53c, but is not limited thereto. For example, the upper insulating layer 53 can be formed from two layers or from more material layers. However, the upper insulating layer 53 may include: an Al2O3 layer; and a SiO2 layer covering the Al2O3 layer. The Al2O3 layer may also be connected to the surface of the first conductive semiconductor layer 25. When the upper insulating layer 53 is formed by both the Al2O3 layer and the SiO2 layer, the Al2O3 layer may be thinner than the SiO2 layer. For example, the Al2O3 layer may have a thickness of about 100 nm to 200 nm, and the SiO2 layer may have a thickness of about 300 nm to 500 nm.

[0067] Al2O3 layers can be formed, for example, using atomic layer deposition (ALD) technology, thereby creating high-density thin films. Al2O3 layers formed via ALD have high density and excellent layer coverage, thus exhibiting excellent blocking properties against external moisture inflow.

[0068] The upper insulating layer 53 may have a hole 53h that exposes the protective metal layer 35. The hole 53h may also penetrate the first insulating layer 31 to expose the protective metal layer 35.

[0069] The upper electrode pad 55 is adjacent to the first conductive semiconductor layer 25 and connected to the second electrode 34, such as the protective metal layer 35. The upper electrode pad 55 can be arranged near the two corners of one side edge of the support substrate 51 and can be horizontally separated from the semiconductor stack structure 30. The upper electrode pad 55 can be connected to the protective metal layer 35 through holes 53h that respectively penetrate the first insulating layer 31 and the upper insulating layer 53.

[0070] The upper electrode pad 55 is insulated from the first conductive semiconductor layer 25. The upper electrode pad 55 is also separated from the first electrode 39.

[0071] The elevation of the surface where the upper electrode pad 55 is connected to the protective metal layer 35 can be located in the region between the first conductive semiconductor layer 25 and the ohmic reflective layer 33, that is, in the region between the bottom surface of the first conductive semiconductor layer 25 and the bottom surface of the second conductive semiconductor layer 29. Therefore, the bottom surface of the upper electrode pad 55 can be located lower than the bottom surface of the first conductive semiconductor layer 29 and higher than the bottom surface of the second conductive semiconductor layer 29. The first insulating layer 31 is located between the bottom surface of the first conductive semiconductor layer 25 and the protective metal layer 35. By making the height of the upper electrode pad 55 higher than the bottom surface of the second conductive semiconductor layer 29, various processes for forming the upper electrode pad 55 can be easily performed, thereby optimizing the LED manufacturing process.

[0072] In this embodiment, as Figure 1 As shown, the light-emitting diode 100 can have a mirror-symmetric structure, thus the current can be uniformly distributed throughout the entire area of ​​the light-emitting diode 100.

[0073] Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 5a , Figure 5b , Figure 6a , Figure 6b , Figure 7a as well as Figure 7b These are top and cross-sectional views illustrating a method for manufacturing a light-emitting diode according to an embodiment of the present invention. The structure of the light-emitting diode according to an embodiment of the present invention will be more clearly understood through the following description of the manufacturing method.

[0074] Reference Figure 3a as well as Figure 3b A semiconductor stack structure 30, comprising a first conductive semiconductor layer 25, an active layer 27, and a second conductive semiconductor layer 29, is formed on a growth substrate 21. The growth substrate 21 can be a sapphire substrate, but is not limited to it; it can be other heterogeneous substrates, such as a silicon substrate. The first conductive semiconductor layer 25 and the second conductive semiconductor layer 29 can be formed as a single layer or multiple layers, respectively. Furthermore, the active layer 27 can be formed as a single quantum well structure or a multiple quantum well structure.

[0075] The compound semiconductor layer can be formed from III-N series compound semiconductors and can be grown on the growth substrate 21 by processes such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0076] On the other hand, a core layer can be formed before forming the compound semiconductor layer. The core layer is used to alleviate the lattice mismatch between the sacrificial substrate 21 and the compound semiconductor layer, and can be a gallium nitride or aluminum nitride and other gallium nitride-based materials.

[0077] Next, the second conductive semiconductor layer 29 and the active layer 27 are patterned to expose the first conductive semiconductor layer 25. This forms a mesa M, through which a first through-hole 32a and a second through-hole 32b are formed. As previously described, the second through-hole 32b is arranged along the edge of the mesa M, and the first through-hole 32a is disposed in the area surrounded by the edge of the mesa M.

[0078] On the other hand, despite Figure 3a as well as Figure 3b A single light-emitting diode (LED) region is shown, but multiple LED regions can be defined on a single growth substrate 21, with segmented regions arranged between them. Figure 3a In this process, the edges of the growth substrate 21 correspond to the dicing regions. In these dicing regions, during the formation of the mesa M, the second conductive semiconductor layer 29 and the active layer 27 are removed, exposing the first conductive semiconductor layer 25. Furthermore, in the region P for forming the upper electrode pad 55 (described later), the second conductive semiconductor layer 29 and the active layer 27 are also removed, exposing the first conductive semiconductor layer 25. By pre-removing the second conductive semiconductor layer 29 and the active layer 27 in the dicing regions and the upper electrode pad formation region P, the upper electrode pad 55 formation process and the light-emitting diode dicing process described later can be facilitated.

[0079] Reference Figure 4a as well as Figure 4b A first insulating layer 31 is formed covering the mesa M. The first insulating layer 31 covers the area around the mesa M and the first conductive semiconductor layer 25 exposed through the first through-hole 32a and the second through-hole 32b, and covers the side surface of the mesa M. The first insulating layer 31 may also cover a portion of the top surface of the second conductive semiconductor layer 29. However, the first insulating layer 31 leaves most of the top surface of the second conductive semiconductor layer 29 exposed.

[0080] The first insulating layer 31 can be deposited using plasma-enhanced chemical vapor deposition and patterned using photolithography and etching techniques.

[0081] On the other hand, an ohmic reflective layer 33 is formed on the second conductive semiconductor layer 29. The ohmic reflective layer 33 can be deposited using electron beam evaporation and can be patterned using a lift-off technique. The sidewalls of the ohmic reflective layer 33 can be connected to the first insulating layer 31, but... Figure 4b As shown, the side of the ohmic reflective layer 33 can be separated from the first insulating layer 31.

[0082] Next, a protective metal layer 35 is formed on the ohmic reflective layer 33. The protective metal layer 35 covers the upper surface of the ohmic reflective layer 33, and also covers and surrounds the edge 33a of the ohmic reflective layer 33. A portion of the protective metal layer 35 can contact the second conductive semiconductor layer 29 between the first insulating layer 31 and the ohmic reflective layer 33. At this time, the protective metal layer 35 can make Schottky contact with the second conductive semiconductor layer 29. Therefore, current will not be directly injected into the second conductive semiconductor layer 29 through the protective metal layer 35, thereby preventing current concentration near the side of the mesa M. Furthermore, when the protective metal layer 35 includes a reflective layer, light incident around the ohmic reflective layer 33 can be reflected, thereby improving light extraction efficiency.

[0083] The protective metal layer 35 exposes the first insulating layer 31 disposed within the first through hole 32a and the second through hole 32b. The protective metal layer 35 has through holes similar in shape to the first through hole 32a and the second through hole 32b, through which the first insulating layer 31 within the first through hole 32a and the second through hole 32b is exposed.

[0084] On the other hand, a portion of the protective metal layer 35 covers the first insulating layer 31 surrounding the mesa M and extends outward from the mesa M. The protective metal layer 35 extending outward from the mesa M is connected to the upper electrode pad 55, which will be described later.

[0085] A second insulating layer 37 is formed on the protective metal layer 35. The second insulating layer 37 covers the top surface and side surfaces of the protective metal layer 35. Therefore, the protective metal layer 35 can be prevented from being exposed to the outside. However, the present invention is not limited to this. The second insulating layer 37 may cover the top surface of the protective metal layer 35 but not the side surfaces. Therefore, in the finished light-emitting diode, the side surfaces of the protective metal layer 35 may also be exposed to the outside.

[0086] Refer to 5a and Figure 5b The second insulating layer 37 and the first insulating layer are photolithographically and etched to form openings in which the first conductive semiconductor layer 25 is exposed inside the first through-hole 32a and the second through-hole 32b. The bottom surface of the opening corresponds to the first contact portion 39a and the second contact portion 39b, which will be described later.

[0087] On the other hand, a first electrode 39 is formed on the second insulating layer 37. The first electrode 39 covers the second insulating layer 37 and includes a first contact portion 39a and a second contact portion 39b that are connected to the first conductive semiconductor layer 25 through an opening penetrating the second insulating layer 37 and the first insulating layer 31. The first contact portion 39a is connected to the first conductive semiconductor layer 25 in the region surrounded by the edge of the mesa M, and the second contact portion 39b is connected to the first conductive semiconductor layer 25 near the edge of the mesa M.

[0088] A first electrode protective metal layer 41 is formed on the first electrode 39. The first electrode protective metal layer 41 is formed to prevent the diffusion of metal elements such as Sn to the first electrode 39, and may contain Ti, Ni, and Au. Alternatively, the first electrode protective metal layer 41 may be omitted.

[0089] Reference Figure 6a as well as Figure 6b The support substrate 51 is attached. The support substrate 51 can be fabricated separately relative to the semiconductor stack structure 30 and then soldered to the first electrode 39 or the first electrode protection metal layer 41 using a solder metal layer 45. In contrast, the support substrate 51 can be formed by plating on the first electrode 39 or the first electrode protection metal layer 41.

[0090] Subsequently, the growth substrate 21 is removed, exposing the surface of the first conductive semiconductor layer 25 of the semiconductor stack structure 30. The growth substrate 21 can be removed, for example, using laser lift-off (LLO) technology. After removing the growth substrate 21, the nitride semiconductor layer 25a can be locally etched to remove the laser-damaged areas.

[0091] On the other hand, the first conductive semiconductor layer 25 is removed along the LED segmentation region. At this time, the first conductive semiconductor layer 25 is also removed in the region P where the upper electrode pad 55 is to be formed. With the removal of the first conductive semiconductor layer 25, the first insulating layer 31 is exposed.

[0092] As explained above, when forming the mesa M, the second conductive semiconductor layer 29 and the active layer 27 are pre-removed in the partitioned region and the upper electrode pad formation region P. Therefore, when removing the semiconductor layer in the partitioned region, only the first conductive semiconductor layer 25 needs to be removed, without the need to additionally remove the second conductive semiconductor layer 29 and the active layer 27. This saves process time in removing the first conductive semiconductor layer 25 in the partitioned region, further simplifying the process.

[0093] Furthermore, in this embodiment, when the first conductive semiconductor layer 25 is removed, no other metal layers, including the protective metal layer 35, are exposed. Consequently, the second conductive semiconductor layer 29 and the active layer 27 are sealed by the first insulating layer 31, thus preventing short circuits caused by etching byproducts of metallic materials, resulting in high process reliability.

[0094] On the other hand, a rough surface R is formed on the surface of the first conductive semiconductor layer 25. The rough surface R can be formed using techniques such as photo-enhanced chemical etching.

[0095] In this embodiment, it is described that the first conductive semiconductor layer 25 is removed from the segmented region before forming a rough surface. However, it is also possible to form a rough surface R first and then remove the first conductive semiconductor layer 25 from the segmented region.

[0096] Reference Figure 7a as well as Figure 7b An upper insulating layer 53 is formed on a first conductive semiconductor layer 25 having a rough surface R. The upper insulating layer 53 may be formed along the rough surface R and have a surface with irregularities corresponding to the rough surface R. The upper insulating layer 53 also covers the first insulating layer 31 exposed around the first conductive semiconductor layer 25.

[0097] As described above, the upper insulating layer 53 may include a first layer 53a, a second layer 53b, and a third layer 53c, but is not limited thereto, and may include two or more layers of Al2O3 and SiO2.

[0098] Next, the upper insulating layer 53 and the first insulating layer 31 are partially removed to form a hole 53h that exposes the protective metal layer 35. The hole 53h is formed in the upper electrode pad region P, thus exposing the protective metal layer 35 extending into the upper electrode pad region P. Subsequently, an upper electrode pad is formed within the hole 53h. Figure 1 (55), divided into individual light-emitting diodes along the segmentation region, thus completing the light-emitting diode (refer to 55). Figure 1 At this point, the first insulating layer 31, the second insulating layer 37, the first electrode 39, the first electrode protective metal layer 41, the welding metal layer 45, and the support substrate 51 can be separated together, thus enabling their sides to be aligned. On the other hand, the ohmic reflective layer 33 and the protective metal layer 35 are located inside the area surrounded by the edges of the separated support substrate, thereby not being exposed to the outside and being buried inside the light-emitting diode.

[0099] In this embodiment, when forming the mesa M, the second conductive semiconductor layer 29 and the active layer 27 are removed first in the upper electrode pad region P. Therefore, compared to the previous case, in the upper electrode pad region P, the heights of the first insulating layer 31 and the upper insulating layer 53 are close to the surface of the first conductive semiconductor layer 25. As a result, the process of forming the hole 53h becomes easier. In addition, even if the height of the top surface of the upper electrode pad 55 is the same, the overall thickness can still be reduced, and the formation process of the upper electrode pad 55 is simplified.

[0100] Figure 8 This is a schematic top view illustrating a light-emitting diode according to another embodiment of the present invention.

[0101] Reference Figure 8 In this embodiment, the light-emitting diode 200 is compared with the reference diode 200. Figure 1 as well as Figure 2 The light-emitting diodes described are generally similar, except that the upper electrode pad 55a is arranged long along one side edge of the support substrate 51.

[0102] That is, in the previous embodiment, it was described that the two upper electrode pads 55 were arranged apart from each other near the two side corners of the support substrate 51, but in this embodiment, one upper electrode pad 55a extends along one side edge of the support substrate 51 to the two side corners.

[0103] The upper electrode pad 55a can be connected to the protective metal layer 35 through a through-hole 53h that penetrates the upper insulating layer 53 and the first insulating layer 31. In this embodiment, the through-hole 53h is formed elongated along the edge of the support substrate 51 in a shape similar to that of the upper electrode pad 55a. The protective metal layer 35 can be exposed across the entire area below the through-hole 53h.

[0104] On the other hand, the second through hole 32b is arranged along the edge of the mesa M. In particular, the second through hole 32b may also be arranged near the edge of the mesa M adjacent to the upper electrode pad 55a.

[0105] Figure 9 This is an image illustrating the light-emitting patterns of a conventional light-emitting diode and a light-emitting diode according to an embodiment of the present invention. Figure 9 (a) shows the light-emitting pattern of a light-emitting diode with an anode electrode pad formed on one side of the support substrate and a cathode electrode pad formed on the epitaxial layer, and thus using the vertical structure of the electrode extension. Figure 9 (b) shows a light-emitting pattern of a light-emitting diode similar to an embodiment of the present invention, but without a second through-hole in which the first contact portion is formed in the first through-hole. Figure 9 (c) shows the light-emitting pattern of a light-emitting diode in which contacts are formed in the first through hole and the second through hole, respectively, according to an embodiment of the present invention.

[0106] Reference Figure 9 As can be confirmed in (a), the light is blocked by the cathode electrode pads and the electrode extension, and the light cannot be emitted uniformly even in the light-emitting area.

[0107] On the contrary, in Figure 9 In (b), light is not blocked in the area other than where the upper electrode pad is formed. However, it can be confirmed that relatively weak light is emitted at the edges of the semiconductor stack structure.

[0108] On the other hand, Figure 9 As can be confirmed in (c), light is emitted across the entire region of the semiconductor stack structure, and in particular, light is emitted even at the edges of the semiconductor stack structure. Figure 9 (b) The light-emitting diode emits more light.

[0109] from Figure 9 As can be confirmed in (b), when the second through-hole is omitted and only the first through-hole is arranged, the first through-hole results in a reduction in the light-emitting area, and consequently, less light is emitted in the edge region of the light-emitting diode. Conversely, as Figure 9 As in (c), arranging a second through-hole in the edge region of the light-emitting diode reduces the number of first through-holes and increases the effective light-emitting area. Furthermore, since the second through-hole is located in the edge region of the light-emitting diode where less light is emitted, the arrangement of the second through-hole does not reduce the effective light-emitting area.

[0110] Based on the results of luminance measurement using the driving current, it was confirmed that the luminance of the light-emitting diode in the embodiment of the present invention is higher than that of the light-emitting diode in the prior art, and the difference in luminance further increases with the increase of current.

[0111] Figure 10 This is an exploded perspective view illustrating a lighting device using a light-emitting diode according to an embodiment of the present invention.

[0112] Reference Figure 10 The lighting device of this embodiment includes a diffuser 1010, a light-emitting element module 1020, and a main body 1030. The main body 1030 can accommodate the light-emitting element module 1020, and the diffuser 1010 can be arranged on the main body 1030 to cover the top of the light-emitting element module 1020.

[0113] The main body 1030 is not limited to any form that accommodates and supports the light-emitting element module 1020 and is capable of supplying power to the light-emitting element module 1020. For example, as shown in the figure, the main body 1030 may include a main body housing 1031, a power supply device 1033, a power supply housing 1035, and a power connection part 1037.

[0114] A power supply device 1033 can be housed within a power supply housing 1035 and electrically connected to the light-emitting element module 1020, and includes at least one IC chip. The IC chip can adjust, convert, or control the power characteristics supplied to the light-emitting element module 1020. The power supply housing 1035 can house and support the power supply device 1033, and the power supply housing 1035, in which the power supply device 1033 is fixed, can be located inside the main housing 1031. A power connection portion 1035 can be arranged at the lower end of the power supply housing 1035 and combined with the power supply housing 1035. Thus, the power connection portion 1037 is electrically connected to the power supply device 1033 inside the power supply housing 1035, and can function as a channel for supplying external power to the power supply device 1033.

[0115] The light-emitting element module 1020 includes a substrate 1023 and light-emitting elements 1021 disposed on the substrate 1023. The light-emitting element module 1020 can be disposed above the main housing 1031 and electrically connected to the power supply device 1033.

[0116] The substrate 1023 is not limited to any substrate capable of supporting the light-emitting element 1021; for example, it can be a printed circuit board including wiring. The substrate 1023 may have a shape corresponding to the fixing portion above the main housing 1031 so as to be stably fixed to the main housing 1031. The light-emitting element 1021 may include at least one of the light-emitting diodes described in the embodiments of the present invention.

[0117] A diffuser 1010 can be arranged on the light-emitting element 1021 and fixed to the main housing 1031 to cover the light-emitting element 1021. The diffuser 1010 can be made of a light-transmitting material, and the light direction characteristics of the lighting device can be adjusted by adjusting the shape and light transmittance of the diffuser 1010. Therefore, the diffuser 1010 can be changed into various forms according to the purpose and applicable form of the lighting device.

[0118] Figure 11 This is a cross-sectional view illustrating a display device using a light-emitting diode to which another embodiment of the present invention is applied.

[0119] The display device of this embodiment includes: a display panel 2110; a backlight unit for providing light to the display panel 2110; and a panel guide for supporting the lower edge of the display panel 2110.

[0120] The display panel 2110 is not particularly limited, and for example, it can be a liquid crystal display panel including a liquid crystal layer. A gate driving PCB (printed circuit board) supplied with driving signals by the gate lines may also be provided at the edge of the display panel 2110. Here, the gate driving PCB may also be formed on a thin film transistor substrate instead of being a separate PCB.

[0121] The backlight unit includes a light source module, which includes at least one substrate and a plurality of light-emitting elements 2160. Furthermore, the backlight unit may also include a bottom cover 2180, a reflective sheet 2170, a diffuser plate 2131, and an optical sheet 2130.

[0122] The bottom cover 2180 can open upwards to accommodate the substrate, the light-emitting element 2160, the reflective sheet 2170, the diffuser plate 2131, and the optical sheet 2130. Additionally, the bottom cover 2180 can be combined with a panel guide. The substrate can be located below the reflective sheet 2170 and arranged to be surrounded by the reflective sheet 2170. However, it is not limited to this; when a reflective material is coated on the surface, it can also be located on the reflective sheet 2170. Furthermore, multiple substrates can be formed and arranged side-by-side, but it is not limited to this; a single substrate can also be formed.

[0123] The light-emitting element 2160 may include the light-emitting diode described in the above embodiment of the present invention. The light-emitting elements 2160 may be arranged regularly in a certain pattern on the substrate. In addition, arranging lenses 2210 on each light-emitting element 2160 can improve the uniformity of light emitted from the multiple light-emitting elements 2160.

[0124] The diffuser plate 2131 and the optical sheet 2130 are located on the light-emitting element 2160. The light emitted from the light-emitting element 2160 can be supplied to the display panel 2110 in the form of a surface light source through the diffuser plate 2131 and the optical sheet 2130.

[0125] Thus, the light-emitting element of this embodiment can be applied to a direct-lit display device such as this embodiment.

[0126] Figure 12 This is a cross-sectional view illustrating a display device using a light-emitting diode to which another embodiment of the present invention is applied.

[0127] The display device having the backlight unit of this embodiment includes: a display panel 3210 for displaying images; and a backlight unit disposed on the back of the display panel 3210 and irradiating light. Furthermore, the display device includes: a frame 3240 for supporting the display panel 3210 and housing the backlight unit; and covers 3270 and 3280 for covering the display panel 3210.

[0128] The display panel 3210 is not particularly limited; for example, it can be a liquid crystal display panel including a liquid crystal layer. A gate driving PCB for supplying driving signals to the gate lines may also be provided at the edge of the display panel 3210. Here, the gate driving PCB may not be constructed as a separate PCB but formed on a thin-film transistor substrate. The display panel 3210 can be fixed by covers 3270 and 3280 located above and below it, with the lower cover 3270 potentially integrated with a backlight unit.

[0129] The backlight unit that provides light to the display panel 3210 includes: a lower cover 3270 with a partial opening on its top surface; a light source module disposed on one side inside the lower cover 3270; and a light guide plate 3250 disposed alongside the light source module to convert point light into surface light. Additionally, the backlight unit in this embodiment may further include: an optical sheet 3230 located on the light guide plate 3250 to diffuse and focus light; and a reflective sheet 3260 disposed below the light guide plate 3250 to reflect light traveling in the downward direction of the light guide plate 3250 toward the display panel 3210.

[0130] The light source module includes a substrate 3220 and a plurality of light-emitting elements 3110 arranged at certain intervals on one side of the substrate 3220. The substrate 3220 is not limited as long as it supports and is electrically connected to the light-emitting elements 3110; for example, it can be a printed circuit board. The light-emitting elements 3110 may include at least one light-emitting diode as described in the above embodiments of the present invention. Light emitted from the light source module is incident on a light guide plate 3250 and supplied to the display panel 3210 through an optical sheet 3230. The point light source emitted from the light-emitting elements 3110 can be converted into a surface light source through the light guide plate 3250 and the optical sheet 3230.

[0131] Thus, the light-emitting element of this embodiment can be applied to edge-type display devices such as those in this embodiment.

[0132] Figure 13 This is a cross-sectional view illustrating an example of a light-emitting diode to which another embodiment of the present invention is applied in a headlamp.

[0133] Reference Figure 13 The headlamp includes a lamp body 4070, a substrate 4020, a light-emitting element 4010, and a cover lens 4050. Furthermore, the headlamp may also include a heat dissipation part 4030, a support rib 4060, and a connecting part 4040.

[0134] The substrate 4020 is fixed and spaced apart on the lamp body 4070 by support ribs 4060. The substrate 4020 is not limited to any substrate capable of supporting the light-emitting element 4010; for example, it can be a substrate with conductive patterns, such as a printed circuit board. The light-emitting element 4010 can be located on the substrate 4020 and supported and fixed by it. Furthermore, the light-emitting element 4010 can be electrically connected to an external power source through the conductive patterns of the substrate 4020. Additionally, the light-emitting element 4010 may include at least one light-emitting diode as described in the above-described embodiment of the invention.

[0135] The cover lens 4050 is located on the path of light emitted from the light-emitting element 4010. For example, as shown, the cover lens 4050 can be arranged separately from the light-emitting element 4010 via the connecting member 4040, and can be arranged in the direction in which light emitted from the light-emitting element 4010 is to be provided. The pointing angle and / or color of the light emitted from the headlamp can be adjusted by the cover lens 4050. On the other hand, the connecting member 4040 can also be arranged around the light-emitting element 4010 to provide a light-emitting path 4045 while fixing the cover lens 4050 to the substrate 4020. In this case, the connecting member 4040 can be formed of a light-reflective material or coated with a light-reflective material. On the other hand, the heat dissipation part 4030 can include a heat sink 4031 and / or a cooling fan 4033, which can dissipate the heat generated when the light-emitting element 4010 is driven to the outside.

[0136] Thus, the light-emitting element of this embodiment can be applied to headlights like those in this embodiment, and is especially applicable to automotive headlights.

[0137] The various embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Furthermore, the content or constituent elements described in one embodiment can be applied to other embodiments without departing from the technical concept of the present invention.

Claims

1. A light-emitting diode, comprising: support base plate; A first conductivity type semiconductor layer is disposed above the support substrate; An upper insulating layer is located on the first conductive semiconductor layer; A mesa, including an active layer and a second conductive semiconductor layer, is located below a portion of the first conductive semiconductor layer to expose the edge of the first conductive semiconductor layer. The mesa includes a plurality of first through-holes and a plurality of second through-holes that penetrate the second conductive semiconductor layer and the active layer to expose the first conductive semiconductor layer. A first electrode is disposed between the second conductive semiconductor layer and the support substrate, and includes a first contact portion electrically connected to the first conductive semiconductor layer through the first through hole and a second contact portion electrically connected to the first conductive semiconductor layer through the second through hole. The second electrode is disposed between the first electrode and the second conductive semiconductor layer and is electrically connected to the second conductive semiconductor layer; as well as At least one upper electrode pad is adjacent to the first conductive semiconductor layer and connected to the second electrode. Each of the plurality of first through-holes is surrounded by an active layer and a second conductive semiconductor layer and arranged in a region surrounded by the edge of the mesa. The plurality of first through-holes are arranged at certain intervals and are spaced apart from the edge of the mesa. Each of the plurality of second through holes is partially surrounded by the active layer and the second conductive semiconductor layer and arranged along the edge of the mesa, and each of the plurality of second through holes is recessed from the edge of the mesa toward the inward side of the mesa. The upper insulating layer comprises multiple material layers.

2. The light-emitting diode according to claim 1, wherein, The first conductive semiconductor layer has a rough surface. The upper insulating layer includes: a first layer covering the rough surface of the first conductive semiconductor layer; a second layer covering the first layer and having a larger refractive index than the first layer; and a third layer covering the second layer and having a smaller refractive index than the second layer.

3. The light-emitting diode according to claim 2, wherein, The first and third layers contain SiO2, and the second layer contains Al2O3.

4. The light-emitting diode according to claim 3, wherein, The first layer is thicker than the second layer and the third layer.

5. The light-emitting diode according to claim 2, wherein, The first conductive semiconductor layer includes an Al-containing nitride semiconductor layer.

6. The light-emitting diode according to claim 1, wherein, The first conductive semiconductor layer has a rough surface. The upper insulating layer includes an Al2O3 layer covering the rough surface of the first conductive semiconductor layer and a SiO2 layer covering the Al2O3 layer.

7. The light-emitting diode according to claim 1, wherein, The support substrate has a rectangular shape. The upper electrode pad is arranged along one side edge of the support substrate between one side edge of the platform and one side edge of the support substrate.

8. The light-emitting diode according to claim 7, wherein, A portion of the second through hole is disposed between the upper electrode pad and the mesa.

9. The light-emitting diode according to claim 1, wherein, The support substrate has a rectangular shape. Two upper electrode pads are arranged near the two corners along one side edge of the support substrate.

10. The light-emitting diode according to claim 9, wherein, A portion of the platform is located between the two upper electrode pads. A portion of the second through hole is formed in a portion of the mesa located between the two upper electrode pads.

11. The light-emitting diode according to claim 10, wherein, The second through holes are arranged adjacent to the four edges of the support substrate.

12. The light-emitting diode according to claim 10, wherein, The light-emitting diode has a mirror-symmetrical structure.

13. The light-emitting diode according to claim 1, wherein, The light-emitting diode also includes: A first insulating layer insulates the first electrode from the first conductive semiconductor layer; and A second insulating layer is located between the first electrode and the second electrode.

14. The light-emitting diode according to claim 13, wherein, The light-emitting diode also includes: A reflective layer is located between the second insulating layer and the first electrode. The reflective layer includes distributed Bragg reflectors.

15. The light-emitting diode according to claim 13, wherein, The light-emitting diode also includes: A welded metal layer is disposed between the first electrode and the support substrate; and A first electrode protective metal layer is located between the welding metal layer and the first electrode, thereby covering the first electrode.

16. The light-emitting diode according to claim 13, wherein, The second electrode includes: an ohmic reflective layer in ohmic contact with the second conductive semiconductor layer; and a protective metal layer protecting the ohmic reflective layer.

17. The light-emitting diode according to claim 16, wherein, The protective metal layer extends outward from the first conductive semiconductor layer. The upper electrode pad is connected to the protective metal layer.

18. The light-emitting diode according to claim 17, wherein, The upper electrode pad is connected to the protective metal layer through the upper insulating layer and the first insulating layer.

19. The light-emitting diode according to claim 16, wherein, The second insulating layer covers the sides of the protective metal layer.

Images