Light emitting diode and preparation method thereof

Abstract

The invention provides a light emitting diode and a preparation method thereof. The light-emitting diode comprises an epitaxial structure and a transparent conductive layer, the epitaxial structure comprises a first through hole, the transparent conductive layer is located on the surface of the epitaxial structure, the transparent conductive layer comprises a second through hole surrounding the first through hole, the second through hole comprises a main body part and a plurality of extension parts, and the extension parts surround the main body part and are connected with the main body part.

Description

Technical Field

[0001] This disclosure relates to the field of light-emitting devices, and in particular to a light-emitting diode and a method for fabricating the same. Background Technology

[0002] Light-emitting diodes (LEDs) are semiconductor devices that emit light. They have advantages such as energy saving, high brightness, high durability, long life and light weight, and have been widely used in lighting and display fields.

[0003] The related technology provides a light-emitting diode (LED) whose structure includes an epitaxial structure and a transparent conductive layer. The epitaxial structure includes a stepped structure with a top surface and a bottom surface, and the transparent conductive layer is located on the top surface of the stepped structure.

[0004] When fabricating the above-mentioned structure of light-emitting diode, the transparent conductive layer is deposited and etched. During the above-mentioned fabrication process, conductive particles of the transparent conductive layer may remain on the epitaxial structure, which can lead to leakage channels and low yield of light-emitting diode. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) and its fabrication method, which can prevent LED leakage and improve LED yield. The technical solution is as follows: A light-emitting diode is provided, the light-emitting diode comprising: an epitaxial structure and a transparent conductive layer; The epitaxial structure includes a first through-hole, the transparent conductive layer is located on the surface of the epitaxial structure, the transparent conductive layer includes a second through-hole surrounding the first through-hole, the second through-hole includes a main body portion and a plurality of extension portions, the plurality of extension portions surrounding the main body portion and connected to the main body portion.

[0006] Optionally, the main body and the first through hole are concentric circles, and the distance between the main body and the first through hole is 3~5μm.

[0007] Optionally, the outline of the extension is arc-shaped, and the distance between the vertex of the extension and the first through hole is 8~15μm.

[0008] Optionally, the second through hole is an axisymmetric shape.

[0009] Optionally, the second through hole includes 4 to 12 of the aforementioned extensions.

[0010] Optionally, the light-emitting diode further includes: a silver mirror layer; the silver mirror layer is located on the surface of the epitaxial structure and covers the transparent conductive layer; The silver mirror layer includes a third through-hole surrounding the first through-hole; The third through hole is located between the first through hole and the second through hole, or a portion of the third through hole is located between the first through hole and the second through hole, and another portion is located outside the second through hole.

[0011] Optionally, the distance between the third through hole and the first through hole is 3~5μm.

[0012] On the other hand, a method for fabricating a light-emitting diode is provided, the method comprising: fabricating an epitaxial structure, the epitaxial structure including a first through-hole; A transparent conductive layer is fabricated on the epitaxial structure. The transparent conductive layer includes a second through-hole surrounding the first through-hole. The second through-hole includes a main body and a plurality of extensions. The plurality of extensions surround the main body and are connected to the main body.

[0013] Optionally, the main body and the first through hole are concentric circles, and the distance between the main body and the first through hole is 3~5μm.

[0014] Optionally, the outline of the extension is arc-shaped, and the distance between the vertex of the extension and the first through hole is 8~15μm.

[0015] The beneficial effects of the technical solutions provided in this disclosure are: To prevent conductive particles remaining in the transparent conductive layer during etching from contacting the sidewalls of the epitaxial structure, the diameter of the second via is usually increased. However, this significantly reduces the area of ​​the transparent conductive layer, resulting in insufficient current spread and reduced brightness of the LED.

[0016] In this embodiment, the second through-hole includes a main body and multiple extensions, which surround and are connected to the main body. Compared to a circular hole, this design significantly increases the overall circumference of the second through-hole, thereby increasing the average distance from each point on the second through-hole to the first through-hole. This greatly reduces the risk of leakage caused by conductive particles contacting the epitaxial sidewall. Furthermore, the distance between the extensions and the first through-hole is relatively close, which ensures the current expansion effect of the transparent conductive layer, thereby improving the brightness of the light-emitting diode.

[0017] In summary, the second via adopts a structure of a main body and multiple extensions, which can ensure the current expansion effect and the brightness of the light-emitting diode as much as possible while avoiding leakage channels between the transparent conductive layer and the epitaxial structure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure; Figure 2 This is a top view of a light-emitting diode provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of the structure of a first through hole and a second through hole provided in an embodiment of this disclosure; Figure 4 This is a normal current conduction diagram of a light-emitting diode provided in an embodiment of the present disclosure; Figure 5 This is a diagram of abnormal current conduction in a light-emitting diode provided by related technologies; Figure 6 This is a schematic diagram of the leakage region of a light-emitting diode provided by related technologies; Figure 7 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure; Figure 8 This is a flowchart of another method for fabricating a light-emitting diode provided in this embodiment.

[0020] The attached figures are labeled as follows: 100: Epitaxial structure; 200: Transparent conductive layer; 300: Substrate; 400: Silver mirror layer; 501: First insulating layer; 502: Second insulating layer; 601: First electrode; 602: Second electrode; 701: First pad; 702: Second pad; 101: First semiconductor layer; 102: Active layer; 103: Second semiconductor layer; 2001: First through hole; 2002: Second through hole; 2003: Main body; 2004: Extension; 2005: Notch; 3000: Third through hole; 3001: Through-hole in the first insulating layer; 3002: Through-hole in the second insulating layer; A: First region; B: Second region; C: Leakage region; D: Current; L1: Distance between the main body and the first through hole; L2: Distance between the apex of the extension and the first through hole. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. Figure 2 This is a top view of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 1 and Figure 2 The light-emitting diode includes an epitaxial structure 100 and a transparent conductive layer 200.

[0023] The epitaxial structure 100 includes a first through hole 2001. A transparent conductive layer 200 is located on the surface of the epitaxial structure 100. The transparent conductive layer 200 includes a second through hole 2002 surrounding the first through hole 2001. The second through hole 2002 includes a main body portion 2003 and a plurality of extension portions 2004. The plurality of extension portions 2004 surround the main body portion 2003 and are connected to the main body portion 2003.

[0024] To prevent conductive particles remaining in the transparent conductive layer during etching from contacting the sidewalls of the epitaxial structure, the diameter of the second via is usually increased. However, this significantly reduces the area of ​​the transparent conductive layer, resulting in insufficient current spread and reduced brightness of the LED.

[0025] In this embodiment, the second through-hole includes a main body and multiple extensions, which surround and are connected to the main body. Compared to a circular hole, this design significantly increases the overall circumference of the second through-hole, thereby increasing the average distance from each point on the second through-hole to the first through-hole. This greatly reduces the risk of leakage caused by conductive particles contacting the epitaxial sidewall. Furthermore, the distance between the extensions and the first through-hole is relatively close, which ensures the current expansion effect of the transparent conductive layer, thereby improving the brightness of the light-emitting diode.

[0026] In summary, the second via adopts a structure of a main body and multiple extensions, which can ensure the current expansion effect and the brightness of the light-emitting diode as much as possible while avoiding leakage channels between the transparent conductive layer and the epitaxial structure.

[0027] Figure 3 This is a schematic diagram of the structure of a first through hole and a second through hole provided in an embodiment of this disclosure. See also... Figure 3 The main body 2003 and the first through hole 2001 are concentric circles, and the distance L1 between the main body 2003 and the first through hole 2001 is 3~5μm.

[0028] In this implementation, the distance between the circular body and the first through hole is 3~5μm. The distance between the circular body and the first through hole is not too close to prevent conductive particles remaining in the transparent conductive layer during the etching process from contacting the sidewall of the epitaxial structure, which would cause leakage of the light-emitting diode. The distance between the circular body and the first through hole is not too far. If the distance between the circular body and the first through hole is too far, the area of ​​the transparent conductive layer will be too small, which would reduce the brightness of the light-emitting diode.

[0029] For example, the distance L1 between the main body 2003 and the first through hole 2001 is 4μm.

[0030] In other embodiments, the main body 2003 and the first through hole 2001 may also be combinations of other shapes, such as the main body 2003 being rectangular and the first through hole 2001 being circular. Alternatively, the main body 2003 may be circular and the first through hole 2001 may be rectangular.

[0031] In this embodiment of the present disclosure, the outline of the extension 2004 is arc-shaped, and the distance L2 between the vertex of the extension 2004 and the first through hole 2001 is 8~15μm.

[0032] In this implementation, the distance between the apex of the extension and the first through hole is 8~15μm, and the overall perimeter of the second through hole is greatly increased, so that the average distance from each point on the second through hole to the first through hole is far, which can greatly reduce the risk of leakage caused by conductive particles contacting the epitaxial sidewall; at the same time, the distance between the main body and the first through hole is only 4μm, thereby ensuring the current expansion effect of the transparent conductive layer and improving the brightness of the light-emitting diode.

[0033] For example, the distance L2 between the apex of the extension 2004 and the first through hole 2001 is 10 μm.

[0034] In other implementations, the outer side of the extension 2004 can also be other shapes, such as U-shaped, V-shaped, L-shaped or other shapes.

[0035] In this embodiment, the second through hole 2002 is an axisymmetric shape.

[0036] In this implementation, the axisymmetric pattern can make the current distribution in the transparent conductive layer more uniform, avoid current accumulation, and improve the yield of the light-emitting diode.

[0037] For example, the second through-hole 2002 is petal-shaped. The petal-shaped structure has a larger perimeter, which makes the average distance between the second through-hole and the first through-hole larger, thereby avoiding the risk of contact leakage; while the petal shape makes part of the second through-hole closer to the first through-hole, which is beneficial for current spread.

[0038] In this embodiment of the disclosure, the second through hole 2002 includes 4 to 12 extensions 2004.

[0039] In this implementation, the second through hole includes 4 to 12 extensions, that is, a maximum of 12 extensions. More than 12 extensions would make the pattern too complex and difficult to manufacture. A minimum of 4 extensions would be required. If there are fewer than 4 extensions, it would be easy for the transparent conductive layer to come into contact with the conductive particles remaining on the epitaxial structure, causing the light-emitting diode to leak current.

[0040] For example, the second through hole 2002 includes four extensions 2004.

[0041] In this embodiment of the disclosure, the included angle between two adjacent extensions 2004 is 30~90°.

[0042] For example, the included angle between two adjacent extensions 2004 is 90°.

[0043] In this embodiment of the disclosure, the transparent conductive layer 200 includes a first region A and a second region B.

[0044] The number of second through holes 2002 in the second region B is greater than the number of second through holes 2002 in the first region A.

[0045] In this implementation, the second through hole corresponds to the first through hole, that is, the number of first through holes in the second region is greater than the number of first through holes in the first region. This allows N-type pads to be set in region B and P-type pads to be set in region A, which facilitates pad placement.

[0046] In this embodiment of the disclosure, the edge of the first region of the transparent conductive layer 200 has a plurality of notches 2005.

[0047] In this implementation, the edge of the first region of the transparent conductive layer has multiple gaps, which can improve the current distribution at the edge of the first region, help to further optimize current spread, reduce current congestion, and improve the light emission uniformity of the light-emitting diode.

[0048] In this embodiment of the disclosure, the epitaxial structure 100 includes a first semiconductor layer 101, an active layer 102, and a second semiconductor layer 103 stacked sequentially, and the bottom of the first via 2001 is located in the first semiconductor layer 101.

[0049] In this embodiment of the disclosure, the first semiconductor layer 101 can be an N-type semiconductor layer, and the second semiconductor layer 103 can be a P-type semiconductor layer.

[0050] For example, the first semiconductor layer 101 can be an N-type GaN layer, and the second semiconductor layer 103 can be a P-type GaN layer.

[0051] In other embodiments, the first semiconductor layer 101 may be a P-type semiconductor layer, and the second semiconductor layer 103 may be an N-type semiconductor layer.

[0052] In this embodiment of the disclosure, the active layer 102 can be a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0053] In this embodiment of the disclosure, the transparent conductive layer 200 may be an indium tin oxide (ITO) layer.

[0054] In this embodiment of the disclosure, the thickness of the transparent conductive layer 200 can be 170 to 250 angstroms.

[0055] For example, the thickness of the transparent conductive layer 200 is 200 angstroms. A thicker transparent conductive layer will absorb light and reduce light emission, while a thinner transparent conductive layer will result in poorer ohmic contact with the epitaxial structure and reduced current spreadability.

[0056] In this embodiment of the disclosure, the light-emitting diode may further include a substrate 300.

[0057] The epitaxial structure 100 is located on the substrate 300.

[0058] In this embodiment of the disclosure, the substrate 300 can be any one of a sapphire patterned substrate, a Si substrate, or a SiC substrate, and the material of the substrate 300 is not limited in this embodiment of the disclosure.

[0059] For example, substrate 300 is a patterned sapphire substrate.

[0060] In this embodiment of the disclosure, the light-emitting diode may further include a silver mirror layer 400.

[0061] The silver mirror layer 400 is located on the surface of the epitaxial structure 100 and covers the transparent conductive layer 200.

[0062] In this embodiment, the silver mirror layer 400 can be a metal stack composed of any material selected from Ag, Ni, Ti, TiW, Al, AlCu, Ti, Ni, Pt, and Au. Ag is the main structure, serving to reflect light and spread current, while Ni and TiW prevent the migration and diffusion of metallic silver.

[0063] like Figure 1 As shown, the silver mirror layer 400 includes a third through-hole 3000 surrounding the first through-hole 2001.

[0064] The third through hole 3000 and the first through hole 2001 can be similar shapes, such as circles.

[0065] Figure 3The diagram shows the location of two types of third through holes 3000. In one example, the third through hole 3000 is located between the first through hole 2001 and the second through hole 2002.

[0066] In another example, a portion of the third through hole 3000 is located between the first through hole 2001 and the second through hole 2002, while another portion is located outside the second through hole 2002.

[0067] In this embodiment, the above two arrangements of the third through hole 300 do not affect the through hole setting of the transparent conductive layer 200, and the silver mirror layer will also cause leakage problems.

[0068] The distance between the third through hole 3000 and the first through hole 2001 can be 3~5μm, for example 4μm.

[0069] In this implementation, the aforementioned through-hole distance ensures the area of ​​the silver mirror layer, thereby guaranteeing the reflection effect.

[0070] In this embodiment of the disclosure, the light-emitting diode may further include: a first insulating layer 501.

[0071] The first insulating layer 501 covers the epitaxial structure 100 and the silver mirror layer 400.

[0072] The first insulating layer 501 includes a first insulating layer through-hole 3001 communicating with the silver mirror layer 400, and a second insulating layer through-hole 3002 communicating with the bottom of the first through-hole 2001.

[0073] In this embodiment of the disclosure, the first insulating layer 501 is a distributed Bragg reflector (DBR) layer or a SiO2 layer, wherein the DBR layer is a stack formed by SiO2 and Ti3O5.

[0074] In this embodiment of the disclosure, the light-emitting diode may further include: a first electrode 601 and a second electrode 602.

[0075] The first electrode 601 and the second electrode 602 are located on the first insulating layer 501. The first electrode 601 is connected to the silver mirror layer 400 through the first insulating layer through hole 3001, and the second electrode 602 is connected to the epitaxial structure 100 through the second insulating layer through hole 3002. The second electrode 602 extends above the surface of the epitaxial structure 100.

[0076] The first electrode 601 and the second electrode 602 can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0077] In this embodiment of the disclosure, the light-emitting diode may further include a second insulating layer 502.

[0078] The second insulating layer 502 covers the first electrode 601, the second electrode 602, and the first insulating layer 501.

[0079] In this embodiment, the second insulating layer 502 is a DBR layer or a SiO2 layer, wherein the DBR layer is a stack formed of SiO2 and Ti3O5.

[0080] In this embodiment of the disclosure, the light-emitting diode further includes: a first pad 701 and a second pad 702.

[0081] The first pad 701 passes through the second insulating layer 502 and is electrically connected to the first electrode 601, and the second pad 702 passes through the second insulating layer 502 and is electrically connected to the second electrode 602.

[0082] In this embodiment of the disclosure, the first pad 701 and the second pad 702 can be a combination of one or more of the following metal or alloy layers: Cr, Al, AlCu, Ti, Ni, Pt, Au, and AuSn.

[0083] It is worth noting that, in the embodiments of this disclosure, the structure can be selectively added or reduced based on the structure of the light-emitting diode described above, and this disclosure does not limit this.

[0084] Figure 4 This is a normal current conduction diagram of a light-emitting diode provided in an embodiment of this disclosure. Figure 4 As can be seen, current D flows in from the first pad 701, connects to the first electrode 601, flows through the silver mirror layer 400, enters the second semiconductor layer 103 through the transparent conductive layer 200, and finally undergoes radiative recombination in the active layer 102. Electrons enter the second electrode 602 from the second pad 702, connect to the first semiconductor layer 101 through the first via 2001, and finally radiatively recombine with holes in the active layer 102 to emit light.

[0085] Figure 5 This is a diagram showing the abnormal current conduction of a light-emitting diode (LED) provided by related technologies. Figure 5 As can be seen, current D flows in from the first pad 701, connects to the first electrode 601, flows through the silver mirror layer 400, and passes through the transparent conductive layer 200, but does not enter the second semiconductor layer 103. Instead, it flows through the surface of the second semiconductor layer 103 and directly connects to the first semiconductor layer 101, causing a short circuit. This results in the current not passing through the interior of the active layer 102, causing a current congestion effect at the leakage channel, resulting in an excessively high current density and generating a large amount of heat that burns out the LED.

[0086] Figure 6 This is a schematic diagram of a leakage region in a light-emitting diode (LED) provided by related technologies. Figure 6It can be seen that in the self-aligned process, the transparent conductive layer 200 and the epitaxial structure 100 are etched in one photolithography step, that is, the transparent conductive layer 200 is etched first and then the epitaxial structure 100 is etched. This process can easily lead to the transparent conductive layer 200 not being etched cleanly, as shown in the leakage area C. At this time, the distance between the transparent conductive layer 200 and the first semiconductor layer 101 is further reduced, the resistance between the transparent conductive layer 200 and the first semiconductor layer 101 is reduced, and it is easier to generate leakage channels, which generates a lot of heat and burns the light-emitting diode.

[0087] In the light-emitting diode provided in this embodiment, the second via 2002 on the transparent conductive layer 200 includes a main body 2003 and multiple extensions 2004. The multiple extensions 2004 are far from the sidewall of the epitaxial structure 10, increasing the resistance between the transparent conductive layer 200 and the sidewall of the epitaxial structure 10, thus avoiding the occurrence of... Figure 5 leakage path and Figure 6 The leakage area C; and the distance between the main body 2003 and the sidewall of the epitaxial structure 10 is closer than the distance between the extension 2004 and the sidewall of the epitaxial structure 10, which can make the transparent conductive layer 200 have a larger current expansion area, thereby improving the brightness of the light-emitting diode.

[0088] Figure 7 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 7 The method includes the following steps: S11. Fabricate an epitaxial structure, wherein the epitaxial structure includes a first through hole.

[0089] S12. A transparent conductive layer is formed on the epitaxial structure. The transparent conductive layer includes a second through hole surrounding the first through hole. The second through hole includes a main body and a plurality of extensions. The plurality of extensions surround the main body and are connected to the main body.

[0090] To prevent conductive particles remaining in the transparent conductive layer during etching from contacting the sidewalls of the epitaxial structure, the diameter of the second via is usually increased. However, this significantly reduces the area of ​​the transparent conductive layer, resulting in insufficient current spread and reduced brightness of the LED.

[0091] In this embodiment, the second through-hole includes a main body and multiple extensions, which surround and are connected to the main body. Compared to a circular hole, this design significantly increases the overall circumference of the second through-hole, thereby increasing the average distance from each point on the second through-hole to the first through-hole. This greatly reduces the risk of leakage caused by conductive particles contacting the epitaxial sidewall. Furthermore, the distance between the extensions and the first through-hole is relatively close, which ensures the current expansion effect of the transparent conductive layer, thereby improving the brightness of the light-emitting diode.

[0092] In summary, the second via adopts a structure of a main body and multiple extensions, which can ensure the current expansion effect and the brightness of the light-emitting diode as much as possible while avoiding leakage channels between the transparent conductive layer and the epitaxial structure.

[0093] Figure 8 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure. See also... Figure 8 The method includes the following steps: S21. A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially formed on a substrate, and the second semiconductor layer, the active layer, and the first semiconductor layer constitute an epitaxial structure.

[0094] The substrate can be any one of the following: a patterned sapphire substrate, a Si substrate, or a SiC substrate.

[0095] In one example, step S21 includes: The first step is to fabricate the first semiconductor layer on the substrate.

[0096] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.

[0097] The second step is to fabricate an active layer on the first semiconductor layer.

[0098] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0099] The third step is to fabricate a second semiconductor layer on the active layer.

[0100] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.

[0101] In this embodiment of the present disclosure, a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially stacked on a substrate.

[0102] S22. Perform patterning on the epitaxial structure, which includes a first through hole.

[0103] In one example, step S22 includes: The first step is to coat the epitaxial structure with a layer of photoresist.

[0104] Of course, the various steps of the embodiments of this disclosure are illustrated by taking photoresist as an example. The mask can also be other shapes, such as hard mask of insulating material, metal mask, etc.

[0105] The second step is to expose and develop the photoresist to form a photoresist mask.

[0106] The third step involves etching the epitaxial structure under the cover of a photoresist mask to form the first via (also known as the MESA via).

[0107] The bottom of the first through-hole is located in the first epitaxial layer.

[0108] In this embodiment of the disclosure, inductively coupled plasma etching (ICP) is used to etch the epitaxial structure.

[0109] The fourth step is to remove the photoresist mask.

[0110] Optionally, this step may also include lithography and etching of isolation trenches at the edge of the epitaxial structure.

[0111] S23. Fabricate a transparent conductive layer on the epitaxial structure.

[0112] In one example, step S23 includes: The first step is to deposit a transparent conductive film on the epitaxial structure using PECVD.

[0113] In this embodiment of the disclosure, the transparent conductive film can be an ITO film.

[0114] The second step is to form a layer of photoresist on the surface of the transparent conductive film.

[0115] The third step is to expose and develop the photoresist to form a photoresist mask.

[0116] It is worth noting that the pattern of the photoresist mask formed in different steps of the embodiments of this disclosure is related to the shape of the film layer or structure to be formed in that step. Therefore, the pattern of the photoresist mask is usually different in different steps.

[0117] The fourth step involves patterning the transparent conductive film using an ITO etching solution under the cover of a photoresist mask to form a transparent conductive layer.

[0118] Step 5: Remove the photoresist mask.

[0119] In this embodiment of the disclosure, the patterned transparent conductive layer includes a second through hole surrounding the first through hole. The second through hole includes a main body and a plurality of extensions, which surround the main body and are connected to the main body.

[0120] In this embodiment, the main body and the first through hole are concentric circles, and the distance between the main body and the first through hole is 3~5μm.

[0121] In this implementation, the distance between the circular body and the first through hole is 3~5μm. The distance between the circular body and the first through hole is not too close to prevent conductive particles remaining in the transparent conductive layer during the etching process from contacting the sidewall of the epitaxial structure, which would cause leakage of the light-emitting diode. The distance between the circular body and the first through hole is not too far. If the distance between the circular body and the first through hole is too far, the area of ​​the transparent conductive layer will be too small, which would reduce the brightness of the light-emitting diode.

[0122] For example, the distance between the main body and the first through hole is 4 μm.

[0123] In this embodiment, the outline of the extension is arc-shaped, and the distance between the vertex of the extension and the first through hole is 8~15μm.

[0124] In this implementation, the distance between the vertex of the extension and the first through hole is 8~15μm, which can ensure that the vertex of the extension and the first through hole are at a certain distance, avoiding contact between the transparent conductive layer and the conductive particles remaining on the sidewall of the epitaxial structure, which would cause the light-emitting diode to leak.

[0125] For example, the distance between the apex of the extension and the first through hole is 10 μm.

[0126] In this embodiment of the disclosure, the second through hole is an axisymmetric shape.

[0127] In this implementation, the axisymmetric pattern can make the current distribution in the transparent conductive layer more uniform, avoid current accumulation, and improve the yield of the light-emitting diode.

[0128] In this embodiment, the second through hole includes 4 to 12 extensions.

[0129] In this implementation, the second through hole includes 4 to 12 extensions, that is, a maximum of 12 extensions. More than 12 extensions would make the pattern too complex and difficult to manufacture. A minimum of 4 extensions would be required. If there are fewer than 4 extensions, it would be easy for the transparent conductive layer to come into contact with the conductive particles remaining on the epitaxial structure, causing the light-emitting diode to leak current.

[0130] For example, the second through hole includes four extensions.

[0131] In this embodiment of the disclosure, the included angle between two adjacent extensions is 30~90°.

[0132] For example, the included angle between two adjacent extensions is 90°.

[0133] In this embodiment of the disclosure, the transparent conductive layer includes a first region and a second region.

[0134] The number of second through holes in the second region is greater than the number of second through holes in the first region.

[0135] In this implementation, the second through hole corresponds to the first through hole, that is, the number of first through holes in the second region is greater than the number of first through holes in the first region, which can disperse the current in the second region and avoid current accumulation.

[0136] In this embodiment of the disclosure, the edge of the first region of the transparent conductive layer has multiple notches.

[0137] In this implementation, the edge of the first region of the transparent conductive layer has multiple gaps, which can improve the current distribution at the edge of the first region, help to further optimize current spread, reduce current congestion, and improve the light emission uniformity of the light-emitting diode.

[0138] S24. A silver mirror layer is fabricated on the epitaxial structure, and the silver mirror layer is covered with a transparent conductive layer.

[0139] In this embodiment, the silver mirror layer can be a metal stack composed of any material selected from Ag, Ni, Ti, TiW, Al, AlCu, Ti, Ni, Pt, and Au. Ag is the main structure, serving to reflect light and spread current, while Ni and TiW prevent the migration and diffusion of metallic silver.

[0140] In one example, step S24 includes: The first step is to form a layer of photoresist on the epitaxial structure.

[0141] The second step is to expose and develop the photoresist to form a photoresist mask, which includes grooves.

[0142] The third step involves sputtering a silver mirror using a sputtering deposition machine under the cover of a photoresist mask.

[0143] The fourth step is to remove the photoresist mask and the silver mirror on the mask, leaving the silver mirror in the groove, thus obtaining the silver mirror layer.

[0144] like Figure 1 As shown, the silver mirror layer 400 includes a third through-hole 3000 surrounding the first through-hole 2001.

[0145] S25. Fabricate a first insulating layer, which covers the substrate, epitaxial structure and silver mirror layer.

[0146] In one example, step S25 includes: The first step is to deposit a first insulating film layer on the substrate, epitaxial structure, and silver mirror layer.

[0147] In this embodiment of the disclosure, when the first insulating film layer is a DBR layer, the first insulating film layer is prepared by an optical coating machine.

[0148] In this embodiment of the disclosure, when the first insulating film layer is a SiO2 layer, the first insulating film layer is deposited by plasma enhanced chemical vapor deposition (PECVD).

[0149] The second step is to form a photoresist layer on the surface of the first insulating film layer.

[0150] The third step is to expose and develop the photoresist to form a photoresist mask.

[0151] The fourth step involves patterning the first insulating layer by etching and / or corroding under the cover of a photoresist mask.

[0152] like Figure 1 As shown, the first insulating layer 501 includes a first insulating layer through hole 3001 communicating with the silver mirror layer 400, and a second insulating layer through hole 3002 communicating with the bottom of the first through hole 2001.

[0153] Step 5: Remove the photoresist mask.

[0154] S26. Fabricate a first electrode and a second electrode on the first insulating layer.

[0155] In one example, step S26 includes: The first step is to form a layer of photoresist on the surface of the first insulating layer.

[0156] The second step is to expose and develop the photoresist to form a photoresist mask, which includes grooves.

[0157] The third step involves depositing metal using a metal evaporation process under the cover of a photoresist mask.

[0158] The fourth step is to remove the photoresist mask and the metal on the mask, leaving the metal in the groove, to obtain the first electrode and the second electrode.

[0159] like Figure 1 As shown, the first electrode 601 is located above the surface of the epitaxial structure 100 and is connected to the silver mirror layer 400 through the first insulating layer through-hole 3001; the second electrode 602 is connected to the epitaxial structure 100 through the second insulating layer through-hole 3002 and extends above the surface of the epitaxial structure 100.

[0160] In the embodiments of this disclosure, the first electrode and the second electrode can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0161] S27. Fabricate a second insulating layer, which covers the first insulating layer, the first electrode, and the second electrode.

[0162] In one example, step S27 includes: The first step is to deposit a second insulating film layer on the first insulating layer, the first electrode, and the second electrode.

[0163] In this embodiment of the disclosure, when the second insulating film layer is a DBR layer, the second insulating film layer is prepared by an optical coating machine.

[0164] In this embodiment of the disclosure, when the second insulating film layer is a SiO2 layer, the second insulating film layer is deposited by PECVD.

[0165] The second step is to form a photoresist layer on the surface of the second insulating film layer.

[0166] The third step is to expose and develop the photoresist to form a photoresist mask.

[0167] The fourth step involves patterning the second insulating layer by etching and / or corroding under the cover of a photoresist mask.

[0168] like Figure 1 As shown, the second insulating layer 502 includes a through hole corresponding to the first electrode 601 and a through hole corresponding to the second electrode 602. Step 5: Remove the photoresist mask.

[0169] S28, Create the first and second pads.

[0170] In one example, step S28 includes: The first step is to form a layer of photoresist on the surface of the second insulating layer.

[0171] The second step is to expose and develop the photoresist to form a photoresist mask, which includes grooves.

[0172] The third step involves depositing metal using a metal evaporation process under the cover of a photoresist mask.

[0173] The fourth step is to remove the photoresist mask and the metal on the mask, leaving the metal in the groove, to obtain the first pad and the second pad.

[0174] like Figure 1 As shown, the first pad 701 passes through the through hole of the second insulating layer 502 and is electrically connected to the first electrode 601, and the second pad 702 passes through the through hole of the second insulating layer 502 and is electrically connected to the second electrode 602.

[0175] In this embodiment of the disclosure, the first pad and the second pad can be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt, Au and AuSn.

[0176] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: an epitaxial structure (100) and a transparent conductive layer (200). The epitaxial structure (100) includes a first through-hole (2001), and the transparent conductive layer (200) is located on the surface of the epitaxial structure (100). The transparent conductive layer (200) includes a second through-hole (2002) surrounding the first through-hole (2001). The second through-hole (2002) includes a main body (2003) and a plurality of extensions (2004). The plurality of extensions (2004) surround the main body (2003) and are connected to the main body (2003).

2. The light-emitting diode according to claim 1, characterized in that, The main body (2003) and the first through hole (2001) are concentric circles, and the distance L1 between the main body (2003) and the first through hole (2001) is 3~5μm.

3. The light-emitting diode according to claim 1, characterized in that, The outline of the extension (2004) is arc-shaped, and the distance L2 between the vertex of the extension (2004) and the first through hole (2001) is 8~15μm.

4. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The second through hole (2002) is an axisymmetric figure.

5. The light-emitting diode according to claim 4, characterized in that, The second through hole (2002) includes 4 to 12 of the aforementioned extensions (2004).

6. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The light-emitting diode further includes a silver mirror layer (400); the silver mirror layer (400) is located on the surface of the epitaxial structure (100) and covers the transparent conductive layer (200). The silver mirror layer (400) includes a third through-hole (3000) surrounding the first through-hole (2001). The third through hole (3000) is located between the first through hole (2001) and the second through hole (2002), or a portion of the third through hole (3000) is located between the first through hole (2001) and the second through hole (2002), and another portion is located outside the second through hole (2002).

7. The light-emitting diode according to claim 6, characterized in that, The distance between the third through hole (3000) and the first through hole (2001) is 3~5μm.

8. A method for fabricating a light-emitting diode, characterized in that, The method includes: An epitaxial structure is fabricated, the epitaxial structure including a first through-hole; A transparent conductive layer is fabricated on the epitaxial structure. The transparent conductive layer includes a second through-hole surrounding the first through-hole. The second through-hole includes a main body and a plurality of extensions. The plurality of extensions surround the main body and are connected to the main body.

9. The method according to claim 8, characterized in that, The main body and the first through hole are concentric circles, and the distance between the main body and the first through hole is 3~5μm.

10. The method according to claim 8, characterized in that, The extension has an arc-shaped profile, and the distance between the vertex of the extension and the first through hole is 8~15μm.

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