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, a first passivation layer, a transparent conductive layer, a second passivation layer and a third passivation layer, the first passivation layer is provided with a first groove, the second passivation layer is provided with a second groove, and the third passivation layer is provided with a third groove; the width of the third groove is larger than that of the second groove, and the width of the second groove is larger than that of the first groove; the first passivation layer is located on the surface of the epitaxial structure, the transparent conductive layer is located on the first passivation layer and penetrates through the first groove to be connected with the epitaxial structure, and a gap is formed between the edge of the transparent conductive layer and the edge of the first passivation layer; the second passivation layer is located on the first passivation layer, and the second passivation layer covers the gap and the edge of the transparent conductive layer; the third passivation layer is located on the second passivation layer.

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] A light-emitting diode (LED) is a semiconductor device that emits light. It has advantages such as energy saving and high durability, and has been widely used in lighting and display fields.

[0003] The related technology provides a light-emitting diode, the structure of which includes an epitaxial structure and a transparent conductive layer, wherein the transparent conductive layer is disposed on the surface of the epitaxial structure.

[0004] However, the current density at the edge of the transparent conductive layer in current LEDs is relatively high, which leads to uneven light emission and consequently, a dimmer LED brightness. Summary of the Invention

[0005] This disclosure provides a light-emitting diode and its fabrication method, which can improve the uniformity of current distribution and increase the brightness of the light-emitting diode. The technical solution is as follows:

[0006] On one hand, a light-emitting diode (LED) is provided, the LED comprising:

[0007] Epitaxial structure, first passivation layer, transparent conductive layer, second passivation layer and third passivation layer;

[0008] The first passivation layer has a first groove, the second passivation layer has a second groove, and the third passivation layer has a third groove;

[0009] The width of the third groove is greater than the width of the second groove, and the width of the second groove is greater than the width of the first groove;

[0010] The first passivation layer is located on the surface of the epitaxial structure, the transparent conductive layer is located on the first passivation layer and passes through the first groove to be connected to the epitaxial structure, and there is a gap between the edge of the transparent conductive layer and the edge of the first passivation layer;

[0011] The second passivation layer is located on the first passivation layer, and the second passivation layer covers the gap and the edge of the transparent conductive layer;

[0012] The third passivation layer is located on the second passivation layer.

[0013] Optionally, the ratio of the distance from the edge of the transparent conductive layer to the center of the transparent conductive layer to the distance from the edge of the transparent conductive layer to the edge of the first passivation layer is 3:1 to 4:1.

[0014] Optionally, the distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5 μm.

[0015] Optionally, the width of the first groove is 30-40 μm, the width of the second groove is 35-45 μm, and the width of the third groove is 40-50 μm.

[0016] Optionally, the thickness of the first passivation layer is 800–1200 angstroms, the thickness of the second passivation layer is 2800–3200 angstroms, and the thickness of the third passivation layer is 1800–2200 angstroms.

[0017] Optionally, the thickness of the transparent conductive layer is 2800–3200 angstroms.

[0018] On the other hand, a method for fabricating a light-emitting diode includes:

[0019] Fabrication of epitaxial structures;

[0020] A first passivation layer is formed on the surface of the epitaxial structure, the first passivation layer having a first groove;

[0021] A transparent conductive layer is fabricated, which is located on the first passivation layer and passes through the first groove to be connected to the epitaxial structure. There is a gap between the edge of the transparent conductive layer and the edge of the first passivation layer.

[0022] A second passivation layer is fabricated, which is located on top of the first passivation layer and covers the gap and the edge of the transparent conductive layer. The second passivation layer has a second groove, the width of which is greater than the width of the first groove.

[0023] A third passivation layer is fabricated, which is located on top of the second passivation layer. The third passivation layer has a third groove, the width of which is greater than the width of the second groove.

[0024] Optionally, the ratio of the distance from the edge of the transparent conductive layer to the center of the transparent conductive layer to the distance from the edge of the transparent conductive layer to the edge of the first passivation layer is 3:1 to 4:1.

[0025] Optionally, the distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5 μm.

[0026] Optionally, the width of the first groove is 30-40 μm, the width of the second groove is 35-45 μm, and the width of the third groove is 40-50 μm.

[0027] The beneficial effects of the technical solutions provided in this disclosure are:

[0028] In this embodiment, the first passivation layer is located on the surface of the epitaxial structure, and the first passivation layer has a first groove, such that the middle part of the transparent conductive layer located on the first passivation layer is located in the first groove, and the edge is located on the first passivation layer. This positional relationship makes the contact area between the transparent conductive layer and the epitaxial structure, i.e. the area of ​​the first groove, easier to control during the manufacturing process, making the contact area between the transparent conductive layer and the epitaxial structure more controllable, avoiding the problem of the transparent conductive layer being too small and difficult to control, improving the boundary effect of the light-emitting diode, and effectively improving the brightness of the light-emitting diode.

[0029] The second passivation layer is located on top of the first passivation layer, covering the gaps at the edge of the transparent conductive layer and providing edge protection. The third passivation layer is located on top of the second passivation layer, reinforcing it and thus improving both luminous efficiency and reliability. Furthermore, grooves with gradually increasing widths are incorporated into the second and third passivation layers to reduce light loss. Attached Figure Description

[0030] 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.

[0031] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0032] Figure 2 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0033] Figure 3 This is a top view of a light-emitting diode provided in an embodiment of this disclosure;

[0034] Figure 4 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure;

[0035] Figure 5 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure embodiment;

[0036] Figure 6 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0037] Figure 7 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0038] Figure 8 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0039] Figure 9 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0040] Figure 10 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0041] Figure 11 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0042] Figure 12 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0043] Figure 13 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of the present disclosure;

[0044] Figure 14 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure.

[0045] The attached figures are labeled as follows:

[0046] 100: Extensional structure;

[0047] 200: First passivation layer; 201: Transparent conductive layer; 202: Second passivation layer; 203: Third passivation layer;

[0048] 300: Electrode structure; 400: Reflective layer; 500: Substrate;

[0049] 301: First electrode; 302: Second electrode; 303: First electrode pad; 304: Second electrode pad;

[0050] 101: First semiconductor layer; 102: Active layer; 103: Second semiconductor layer;

[0051] 1001: Stepped structure; 1002: First groove; 1003: Second groove; 1004: Third groove;

[0052] 2001: First through hole; 2002: Second through hole;

[0053] a: Distance from the edge of the transparent conductive layer to the center of the transparent conductive layer; b: Distance from the edge of the transparent conductive layer to the edge of the first passivation layer; c: Distance between the edge of the second groove and the edge of the transparent conductive layer. Detailed Implementation

[0054] 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.

[0055] The boundary effect refers to the phenomenon that when the size of a light-emitting diode (LED) decreases, the current density at the boundary is higher, making the edges brighter while the central area is relatively darker, thus affecting the uniformity of light emission.

[0056] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 1 The light-emitting diode includes: an epitaxial structure 100, a first passivation layer 200, a transparent conductive layer 201, a second passivation layer 202, and a third passivation layer 203.

[0057] The first passivation layer 200 has a first groove 1002, the second passivation layer 202 has a second groove 1003, and the third passivation layer 203 has a third groove 1004.

[0058] The width of the third groove 1004 is greater than the width of the second groove 1003, and the width of the second groove 1003 is greater than the width of the first groove 1002.

[0059] The first passivation layer 200 is located on the surface of the epitaxial structure 100, the transparent conductive layer 201 is located on the first passivation layer 200 and passes through the first groove 1002 and is connected to the epitaxial structure 100, and there is a gap between the edge of the transparent conductive layer 201 and the edge of the first passivation layer 200.

[0060] The second passivation layer 202 is located on the first passivation layer 200, and the second passivation layer 202 covers the gaps and the edge of the transparent conductive layer 201.

[0061] The third passivation layer 203 is located on the second passivation layer 202.

[0062] In this embodiment, the first passivation layer is located on the surface of the epitaxial structure, and the first passivation layer has a first groove, such that the middle part of the transparent conductive layer located on the first passivation layer is located in the first groove, and the edge is located on the first passivation layer. This positional relationship makes the contact area between the transparent conductive layer and the epitaxial structure, i.e. the area of ​​the first groove, easier to control during the manufacturing process, making the contact area between the transparent conductive layer and the epitaxial structure more controllable, avoiding the problem of the transparent conductive layer being too small and difficult to control, improving the boundary effect of the light-emitting diode, and effectively improving the brightness of the light-emitting diode.

[0063] The second passivation layer is located on top of the first passivation layer, covering the gaps at the edge of the transparent conductive layer and providing edge protection. The third passivation layer is located on top of the second passivation layer, reinforcing it and thus improving both luminous efficiency and reliability. Furthermore, grooves with gradually increasing widths are incorporated into the second and third passivation layers to reduce light loss.

[0064] In this embodiment of the disclosure, the distance c between the edge of the second groove 1003 and the edge of the transparent conductive layer 201 is greater than 5 μm.

[0065] In this implementation, the distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5μm. This distance is not too small, which would cause the transparent conductive layer to be too close to the edge of the light-emitting diode, resulting in current concentration at the edge and a high current density at the edge of the light-emitting diode, thus causing a boundary effect. This distance is not too large, which would cause the current expansion area of ​​the transparent conductive layer to be too small, resulting in low brightness of the light-emitting diode.

[0066] For example, the distance c between the edge of the second groove 1003 and the edge of the transparent conductive layer 201 is 10 μm.

[0067] In one possible implementation of this disclosure, the projections of the first groove 1002, the second groove 1003, and the third groove 1004 onto the surface of the extension structure 100 can be rectangular.

[0068] In another possible implementation of the present disclosure, the projections of the first groove 1002, the second groove 1003, and the third groove 1004 onto the surface of the epitaxial structure 100 can be circular or elliptical, etc.

[0069] In this embodiment of the disclosure, the width of the first groove 1002 is 30-40 μm, the width of the second groove 1003 is 35-45 μm, and the width of the third groove 1004 is 40-50 μm.

[0070] Taking a rectangle as an example, the width is the same as the rectangle's width; taking a circle as an example, the width is the same as the circle's diameter.

[0071] In this implementation, the first groove adopts the aforementioned dimensions to limit the contact area between the transparent conductive layer and the epitaxial layer, preventing the transparent conductive layer from being too close to the edge of the epitaxial structure and reducing the boundary effect of the transparent conductive layer. The second and third grooves adopt the aforementioned dimensions, which on the one hand allows the remaining second and third passivation layers to provide better edge protection and reinforcement, improving the brightness and yield of the light-emitting diode; on the other hand, it ensures sufficient space for the subsequent fabrication of the electrode structure.

[0072] For example, the width of the first groove 1002 is 35 μm, the width of the second groove 1003 is 40 μm, and the width of the third groove 1004 is 45 μm.

[0073] In this embodiment of the disclosure, the thickness of the first passivation layer 200 can be 800 to 1200 angstroms, the thickness of the second passivation layer 202 can be 2800 to 3200 angstroms, and the thickness of the third passivation layer 203 can be 1800 to 2200 angstroms.

[0074] In this implementation, the first passivation layer adopts the aforementioned thickness, which on the one hand can limit the contact between the current spreading layer and the epitaxial layer; on the other hand, the thickness of the first passivation layer is smaller than that of the current spreading layer, which can prevent the transparent conductive layer from cracking at the edge of the groove due to bending while limiting the effective contact area between the transparent conductive layer and the epitaxial structure.

[0075] The second and third passivation layers use the aforementioned thickness, which achieves both edge protection and reinforcement while avoiding an overall thickness that would be detrimental to chip size.

[0076] For example, the thickness of the first passivation layer 200 is 1000 angstroms, the thickness of the second passivation layer 202 is 3000 angstroms, and the thickness of the third passivation layer 203 is 2000 angstroms.

[0077] In this embodiment of the disclosure, the thickness of the transparent conductive layer 201 can be 2800 to 3200 angstroms.

[0078] In this implementation, the transparent conductive layer has the aforementioned thickness, which is greater than the thickness of the first passivation layer. This is beneficial to the overall flatness of the transparent conductive layer and makes it less prone to cracking.

[0079] For example, the thickness of the transparent conductive layer 201 is 3000 angstroms.

[0080] In this embodiment of the disclosure, the distance from the inner edge of the second passivation layer 202 to the edge of the transparent conductive layer 201 is less than 5 μm.

[0081] In this implementation, the distance from the inner edge of the second passivation layer to the edge of the transparent conductive layer is less than 5 μm, which avoids the transparent conductive layer being too close to the edge of the epitaxial structure and causing an edge effect. At the same time, the second passivation layer can also play an edge protection role.

[0082] For example, the distance from the edge of the second passivation layer 202 to the edge of the transparent conductive layer 201 is 3 μm.

[0083] In this embodiment, the first passivation layer 200, the second passivation layer 202, and the third passivation layer 203 can be SiO2, Si3N4, or SiN. x Or a passivation layer made of SiON. Where x is greater than 0.

[0084] In this implementation, the aforementioned material has good insulation properties, which can limit the current spread range of the transparent conductive layer.

[0085] For example, the first passivation layer 200, the second passivation layer 202 and the third passivation layer 203 are SiO2 layers.

[0086] In this embodiment of the disclosure, the transparent conductive layer 201 may be an indium tin oxide (ITO) layer.

[0087] Figure 2 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 2 The extensional structure 100 is a stepped structure 1001, which includes a top surface and a bottom surface.

[0088] The light-emitting diode also includes an electrode structure 300 and a reflective layer 400, the reflective layer 400 covering the transparent conductive layer 201, the bottom surface of the step, and the top surface of the step. The electrode structure 300 is electrically connected to the transparent conductive layer 201 and the bottom surface of the step.

[0089] 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 together. The top surface of the step is located on the second semiconductor layer 103, and the bottom surface of the step is located on the first semiconductor layer 101.

[0090] In this embodiment, the electrode structure 300 includes a first electrode 301, a second electrode 302, a first electrode pad 303, and a second electrode pad 304. A transparent conductive layer 201 is located on the top surface of the step. The first electrode 301 is located within the second groove 1003 and the third groove 1004 and is connected to the transparent conductive layer 201. The second electrode 302 is connected to the bottom surface of the step. The first electrode pad passes through the reflective layer 400 and is connected to the first electrode 301. The second electrode pad 304 passes through the reflective layer 400 and is connected to the second electrode 302.

[0091] In this embodiment of the present disclosure, the light-emitting diode further includes a substrate 500, and an epitaxial structure 100 is located on the substrate 500.

[0092] In this embodiment of the disclosure, the substrate 500 can be any one of a sapphire substrate, a Si substrate, or a SiC substrate, and the material of the substrate 500 is not limited in this embodiment of the disclosure.

[0093] For example, substrate 500 is a sapphire substrate.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] In this embodiment of the disclosure, the first electrode 301, the second electrode 302, the first electrode pad 303, and the second electrode pad 304 can be electrodes or electrode pads with chromium as the base material.

[0099] In this embodiment of the disclosure, the thickness of the first electrode 301 and the second electrode 302 may be less than 100 angstroms.

[0100] For example, the thickness of the first electrode 301 and the second electrode 302 is 80 angstroms.

[0101] In this embodiment of the disclosure, the reflective layer 400 may be a distributed Bragg reflector (DBR) layer.

[0102] In this embodiment of the disclosure, the DBR layer can be a stack of alternating SiO2 and Ti3O5 layers.

[0103] In this embodiment of the disclosure, the alternation period of the SiO2 layer and the Ti3O5 layer can be 4 to 13 cycles.

[0104] For example, the alternation period of SiO2 layer and Ti3O5 layer can be 6 cycles.

[0105] In this embodiment of the disclosure, the light-emitting diode may further include a protective layer 600.

[0106] In this embodiment of the present disclosure, the protective layer 600 covers the sidewalls of the epitaxial structure 100, the sidewalls of the first passivation layer 200, the sidewalls of the second passivation layer 202, the sidewalls of the third passivation layer 203, the sidewalls of the reflective layer 400, and the top surface, and exposes a portion of the first electrode pad 303 and the second electrode pad 304.

[0107] In this embodiment, the protective layer 600 can be SiO2, Si3N4, or SiN. x Alternatively, a protective layer made of SiON. Where x can be greater than 0.

[0108] For example, the protective layer 600 is a SiO2 layer.

[0109] Figure 3 This is a top view of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 3 The ratio of the distance a from the edge of the transparent conductive layer 201 to the center of the transparent conductive layer 201 to the distance b from the edge of the transparent conductive layer 201 to the edge of the first passivation layer 200 is 3:1 to 4:1.

[0110] In this implementation, the above ratio can reduce the boundary effect of the transparent conductive layer while reasonably setting the area of ​​the transparent conductive layer, thereby improving the brightness of the light-emitting diode.

[0111] For example, the ratio of the distance a from the edge of the transparent conductive layer 201 to the center of the transparent conductive layer 201 to the distance b from the edge of the transparent conductive layer 201 to the edge of the first passivation layer 200 is 3:1.

[0112] For example, the distance a from the edge of the transparent conductive layer 201 to the center of the transparent conductive layer 201 is 35 μm, and the distance b from the edge of the transparent conductive layer 201 to the edge of the first passivation layer 200 is 15 μm.

[0113] 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.

[0114] Figure 4 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 4 The method includes the following steps:

[0115] S11. Fabricate the extensional structure.

[0116] S12. A first passivation layer is formed on the surface of the epitaxial structure, the first passivation layer having a first groove.

[0117] S13. Fabricate a transparent conductive layer, wherein the transparent conductive layer is located on the first passivation layer and passes through the first groove and is connected to the epitaxial structure, and there is a gap between the edge of the transparent conductive layer and the edge of the first passivation layer.

[0118] S14. Fabricate a second passivation layer, the second passivation layer being located on the first passivation layer and covering the gap and the edge of the transparent conductive layer, the second passivation layer having a second groove, the width of the second groove being greater than the width of the first groove.

[0119] S15. Fabricate a third passivation layer, the third passivation layer being located on the second passivation layer, the third passivation layer having a third groove, the width of the third groove being greater than the width of the second groove.

[0120] In this embodiment, the first passivation layer is located on the surface of the epitaxial structure, and the first passivation layer has a first groove, such that the middle part of the transparent conductive layer located on the first passivation layer is located in the first groove, and the edge is located on the first passivation layer. This positional relationship makes the contact area between the transparent conductive layer and the epitaxial structure, i.e. the area of ​​the first groove, easier to control during the manufacturing process, making the contact area between the transparent conductive layer and the epitaxial structure more controllable, avoiding the problem of the transparent conductive layer being too small and difficult to control, improving the boundary effect of the light-emitting diode, and effectively improving the brightness of the light-emitting diode.

[0121] The second passivation layer is located on top of the first passivation layer, covering the gaps at the edge of the transparent conductive layer and providing edge protection. The third passivation layer is located on top of the second passivation layer, reinforcing it and thus improving both luminous efficiency and reliability. Furthermore, grooves with gradually increasing widths are incorporated into the second and third passivation layers to reduce light loss.

[0122] Figure 5 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure. See also... Figure 5 The method includes the following steps:

[0123] 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.

[0124] The substrate can be any one of the following: patterned sapphire substrate (PPS), Si substrate, and SiC substrate.

[0125] For example, the substrate is a patterned sapphire substrate.

[0126] In one example, step S21 includes:

[0127] The first step is to fabricate the first semiconductor layer.

[0128] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.

[0129] The second step is to create the active layer.

[0130] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0131] The third step is to fabricate the second semiconductor layer.

[0132] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.

[0133] 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.

[0134] In the embodiments disclosed herein, the above-mentioned semiconductor layer can be grown using a Veeco K465i, C4, or RB MOCVD (Metal Organic Chemical Vapor Deposition) apparatus or an AIXTRON MOCVD apparatus. High-purity H2 (hydrogen), high-purity N2 (nitrogen), or a mixture of high-purity H2 and high-purity N2 is used as the carrier gas; high-purity NH3 is used as the N source; trimethylgallium (TMGa) and triethylgallium (TEGa) are used as gallium sources; trimethylindium (TMIn) is used as the indium source; silane (SiH4) is used as the N-type dopant; trimethylaluminum (TMAl) is used as the aluminum source; and magnesium pyrocene (CP2Mg) is used as the P-type dopant.

[0135] S22. The extensional structure is graphically processed to form a step structure, which includes the top surface and the bottom surface of the step.

[0136] For example, step S22 may include:

[0137] A patterned mask layer is formed on the surface of the second semiconductor layer; under the cover of the mask layer, the epitaxial structure is etched to form a step extending to the first semiconductor layer.

[0138] Figure 6 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 6 The epitaxial structure 100 includes a first semiconductor layer 101, an active layer 102, and a second semiconductor layer 103. The first semiconductor layer 101, the active layer 102, and the second semiconductor layer 103 are sequentially grown on the substrate 500. The epitaxial structure 100 has a step structure 1001, which includes a step top surface and a step bottom surface. The step bottom surface is located on the first semiconductor layer 101, and the step top surface is located on the second semiconductor layer 103.

[0139] S23. A first passivation layer is formed on the surface of the epitaxial structure, the first passivation layer having a first groove.

[0140] For example, step S23 may include:

[0141] The first step is to fabricate a first passivation film on the surface of the epitaxial structure.

[0142] In this embodiment, the first passivation film layer can be SiO2, Si3N4, or SiN. xOr a passivation film made of SiON. Where x is greater than 0.

[0143] In this implementation, the aforementioned material has good insulation properties, which can limit the current spread range of the transparent conductive layer.

[0144] For example, the first passivation film is a SiO2 film.

[0145] In this embodiment of the disclosure, the thickness of the first passivation film layer can be 800 to 1200 angstroms.

[0146] In this implementation, the first passivation layer adopts the aforementioned thickness, which on the one hand can limit the contact between the current spreading layer and the epitaxial layer; on the other hand, the thickness of the first passivation layer is smaller than that of the current spreading layer, which can prevent the transparent conductive layer from cracking at the edge of the groove due to bending while limiting the effective contact area between the transparent conductive layer and the epitaxial structure.

[0147] For example, the thickness of the first passivation film is 1000 angstroms.

[0148] The second step is to pattern the first passivation film to obtain the first passivation layer.

[0149] In this embodiment of the disclosure, the first passivation film is patterned to form a first passivation layer having a first groove.

[0150] In one possible implementation of this disclosure, the projection of the first groove onto the surface of the epitaxial structure can be rectangular.

[0151] In another possible implementation of the present disclosure, the projection of the first groove onto the surface of the epitaxial structure can be circular or elliptical, etc.

[0152] In this embodiment of the disclosure, the width of the first groove can be 30 to 40 μm.

[0153] Taking a rectangle as an example, the width is the same as the rectangle's width; taking a circle as an example, the width is the same as the circle's diameter.

[0154] In this implementation, the first groove adopts the above-mentioned dimensions to limit the contact area between the transparent conductive layer and the epitaxial layer, avoid the transparent conductive layer and the edge of the epitaxial structure being too close, and reduce the boundary effect of the transparent conductive layer; on the other hand, it can ensure that there is enough space to facilitate the subsequent fabrication of the electrode structure.

[0155] For example, the width of the first groove is 35 μm.

[0156] Figure 7 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 7The first passivation layer 200 is on the epitaxial structure 100 and has a first groove 1002.

[0157] S24. Fabricate a transparent conductive layer. The transparent conductive layer is located in the first passivation layer and passes through the first groove to connect with the epitaxial structure. There is a gap between the edge of the transparent conductive layer and the edge of the first passivation layer.

[0158] For example, step S24 may include:

[0159] The first step is to create a transparent conductive film layer.

[0160] In this embodiment of the disclosure, the transparent conductive film layer can be an ITO film layer.

[0161] In this embodiment of the disclosure, the thickness of the transparent conductive film layer can be 2800 to 3200 angstroms.

[0162] In this implementation, the transparent conductive layer has the aforementioned thickness, which is greater than the thickness of the first passivation layer. This is beneficial to the overall flatness of the transparent conductive layer and makes it less prone to cracking.

[0163] For example, the thickness of the transparent conductive film layer can be 3000 angstroms.

[0164] The second step is to pattern the transparent conductive film layer to form a transparent conductive layer.

[0165] In this embodiment of the disclosure, patterning the transparent conductive film layer may include: spin-coating photoresist; forming a mask pattern by exposure and development; and performing wet etching on the transparent conductive film layer under the cover of the mask pattern to form a transparent conductive layer.

[0166] In the embodiments of this disclosure, the ratio of the distance from the edge of the transparent conductive layer to the center of the transparent conductive layer to the distance from the edge of the transparent conductive layer to the edge of the first passivation layer is 3:1 to 4:1.

[0167] In this implementation, the above ratio can reduce the boundary effect of the transparent conductive layer while reasonably setting the area of ​​the transparent conductive layer, thereby improving the brightness of the light-emitting diode.

[0168] For example, the ratio of the distance from the edge of the transparent conductive layer to the center of the transparent conductive layer to the distance from the edge of the transparent conductive layer to the edge of the first passivation layer is 3:1.

[0169] Figure 8 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 8 The transparent conductive layer 201 is located on the first passivation layer 200 and passes through the first groove 1002 of the first passivation layer 200 to connect with the epitaxial structure 100.

[0170] S25. Fabricate a second passivation layer, which is located on the first passivation layer and covers the gap and the edge of the transparent conductive layer. The second passivation layer has a second groove, the width of which is greater than the width of the first groove.

[0171] For example, step S25 may include:

[0172] The first step is to fabricate a second passivation film layer on the surface of the first passivation layer and the surface of the transparent conductive layer.

[0173] In this embodiment, the second passivation film can be SiO2, Si3N4, or SiN. x Or a passivation film made of SiON. Where x is greater than 0.

[0174] In this implementation, the aforementioned material has good insulation properties, which can limit the current spread range of the transparent conductive layer.

[0175] For example, the second passivation film is a SiO2 film.

[0176] In this embodiment of the disclosure, the thickness of the second passivation film can be 2800 to 3200 angstroms.

[0177] In this implementation, the second passivation layer adopts the aforementioned thickness, which can achieve both edge protection and reinforcement effects, while avoiding an overall thickness that is too large and detrimental to chip size.

[0178] For example, the thickness of the second passivation film is 3000 angstroms.

[0179] The second step is to pattern the second passivation film to obtain the second passivation layer.

[0180] In this embodiment of the disclosure, the second passivation film layer is patterned to form a second passivation layer with a second groove.

[0181] In one possible implementation of this disclosure, the projection of the second groove onto the surface of the epitaxial structure can be rectangular.

[0182] In another possible implementation of the present disclosure, the projection of the second groove onto the surface of the epitaxial structure can be circular or elliptical, etc.

[0183] In this embodiment of the disclosure, the width of the second groove can be 35 to 45 μm.

[0184] Taking a rectangle as an example, the width is the same as the rectangle's width; taking a circle as an example, the width is the same as the circle's diameter.

[0185] In this implementation, the second groove adopts the above-mentioned dimensions, which on the one hand enables the remaining second passivation layer to play a better role in edge protection and reinforcement, thereby improving the brightness and yield of the light-emitting diode; on the other hand, it ensures that there is enough space to facilitate the subsequent fabrication of the electrode structure.

[0186] For example, the width of the second groove is 40 μm.

[0187] In this embodiment of the disclosure, the distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5 μm.

[0188] In this implementation, the distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5μm. This distance is not too small, which would cause the transparent conductive layer to be too close to the edge of the light-emitting diode, resulting in current concentration at the edge and a high current density at the edge of the light-emitting diode, thus causing a boundary effect. This distance is not too large, which would cause the current expansion area of ​​the transparent conductive layer to be too small, resulting in low brightness of the light-emitting diode.

[0189] For example, the distance between the edge of the second groove and the edge of the transparent conductive layer is 10 μm.

[0190] In this embodiment of the disclosure, the distance from the edge of the second passivation layer to the inner edge of the transparent conductive layer is less than 5 μm.

[0191] In this implementation, the distance from the inner edge of the second passivation layer to the edge of the transparent conductive layer is less than 5 μm, which avoids the transparent conductive layer being too close to the edge of the epitaxial structure and causing an edge effect. At the same time, the second passivation layer can also play an edge protection role.

[0192] For example, the distance from the edge of the second passivation layer to the inner edge of the transparent conductive layer is 3 μm.

[0193] Figure 9 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 9 The second passivation layer 202 wraps around the edge of the transparent conductive layer 201 on the first passivation layer 200, and the second passivation layer 202 has a second groove 1003.

[0194] S26. Fabricate a third passivation layer, which is located on the second passivation layer. The third passivation layer has a third groove, the width of which is greater than the width of the second groove.

[0195] For example, step S26 may include:

[0196] The first step is to fabricate a third passivation film layer on the surface of the second passivation layer.

[0197] In this embodiment, the third passivation film can be SiO2, Si3N4, or SiN. xOr a passivation film made of SiON. Where x is greater than 0.

[0198] In this implementation, the aforementioned material has good insulation properties, which can limit the current spread range of the transparent conductive layer.

[0199] For example, the third passivation film layer is a SiO2 layer.

[0200] In this embodiment of the disclosure, the thickness of the third passivation film layer can be 1800 to 2200 angstroms.

[0201] In this implementation, the third passivation layer adopts the aforementioned thickness, which can achieve both edge protection and reinforcement effects, while avoiding an overall thickness that is too large and detrimental to chip size.

[0202] The second step is to pattern the third passivation film layer to obtain the third passivation layer.

[0203] In this embodiment of the disclosure, the third passivation film layer is patterned to form a third passivation layer with a third groove.

[0204] In one possible implementation of this disclosure, the projection of the second groove onto the surface of the epitaxial structure can be rectangular.

[0205] In another possible implementation of the present disclosure, the projection of the second groove onto the surface of the epitaxial structure can be circular or elliptical, etc.

[0206] In this embodiment of the disclosure, the width of the third groove can be 40 to 50 μm.

[0207] Taking a rectangle as an example, the width is the same as the rectangle's width; taking a circle as an example, the width is the same as the circle's diameter.

[0208] In this implementation, the third groove adopts the above-mentioned dimensions, which on the one hand enables the remaining third passivation layer to play a better role in edge protection and reinforcement, thereby improving the brightness and yield of the light-emitting diode; on the other hand, it ensures that there is enough space to facilitate the subsequent fabrication of the electrode structure.

[0209] For example, the width of the third groove is 45 μm.

[0210] Figure 10 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 10 The third passivation layer 203 is located on the second passivation layer 202, and the third passivation layer 203 has a third groove 1004.

[0211] S27. Fabricate the first and second electrodes.

[0212] In this embodiment of the disclosure, the first electrode and the second electrode can be fabricated by stripping the negative electrode.

[0213] In this embodiment of the disclosure, the first electrode and the second electrode can be electrodes or electrode pads with chromium as the base material.

[0214] In this embodiment of the disclosure, the thickness of the first electrode and the second electrode can be less than 100 angstroms.

[0215] For example, the thickness of the first electrode and the second electrode is 80 angstroms.

[0216] Figure 11 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 11 The first electrode 301 is located in the third groove 1004 and the second groove 1003 and is connected to the transparent conductive layer 201. The second electrode 302 is located on the bottom surface of the step and is connected to the first semiconductor 101.

[0217] S28. Create a reflective layer.

[0218] In this embodiment of the disclosure, the reflective layer may be a DBR layer.

[0219] In this embodiment of the disclosure, the DBR layer can be a stack of alternating SiO2 and Ti3O5 layers.

[0220] In this embodiment of the disclosure, the alternation period of the SiO2 layer and the Ti3O5 layer can be 4 to 13 cycles.

[0221] For example, the alternation period of SiO2 layer and Ti3O5 layer can be 6 cycles.

[0222] Figure 12 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 12 The reflective layer covers the third passivation layer 203, the second passivation layer 202, the transparent conductive layer 201, the epitaxial structure 10, the first electrode 301, and the second electrode 302.

[0223] S29. Make openings on the reflective layer corresponding to the first and second electrodes.

[0224] In this embodiment of the disclosure, the reflective layer is perforated by wet etching or dry etching.

[0225] A first through hole is formed by opening a hole in the first electrode structure on the reflective layer, and a second through hole is formed by opening a hole in the second electrode structure on the reflective layer.

[0226] Figure 13This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 13 The reflective layer 400 has a first through-hole 2001 and a second through-hole 2002.

[0227] S30. A first electrode pad and a second electrode pad are fabricated on the reflective layer. The first electrode pad passes through the first through hole and is connected to the first electrode, and the second electrode pad passes through the second through hole and is connected to the second electrode.

[0228] In this embodiment of the disclosure, the first electrode pad and the second electrode pad can be fabricated by negative electrode stripping.

[0229] In this embodiment of the disclosure, the first electrode pad and the second electrode pad can be electrodes or electrode pads with chromium as the base material.

[0230] Figure 14 This is a schematic diagram illustrating the structure of a light-emitting diode (LED) during its fabrication process, as provided in an embodiment of this disclosure. See also... Figure 14 The first electrode pad 303 passes through the first through hole 2001 and is connected to the first electrode 301, and the second electrode pad 304 passes through the second through hole 2002 and is connected to the second electrode 302.

[0231] S31. Create a protective layer that covers the surface of the epitaxial structure, the first passivation layer, the second passivation layer, the third passivation layer, the reflective layer, the first electrode pad, and the second electrode pad, and exposes a portion of the first electrode pad and the second electrode pad.

[0232] In this embodiment, the protective layer may be SiO2, Si3N4, or SiN. x Or a protective layer made of SiON. Where x is greater than 0.

[0233] For example, the protective layer is a SiO2 layer.

[0234] 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), a first passivation layer (200), a transparent conductive layer (201), a second passivation layer (202), and a third passivation layer (203); The first passivation layer (200) has a first groove (1002), the second passivation layer (202) has a second groove (1003), and the third passivation layer (203) has a third groove (1004); The width of the third groove (1004) is greater than the width of the second groove (1003), and the width of the second groove (1003) is greater than the width of the first groove (1002). The first passivation layer (200) is located on the surface of the epitaxial structure (100), the transparent conductive layer (201) is located on the first passivation layer (200) and passes through the first groove (1002) and is connected to the epitaxial structure (100), and there is a gap between the edge of the transparent conductive layer (201) and the edge of the first passivation layer (200); The second passivation layer (202) is located on the first passivation layer (200), and the second passivation layer (202) covers the gap and the edge of the transparent conductive layer (201); The third passivation layer (203) is located on the second passivation layer (202).

2. The light-emitting diode according to claim 1, characterized in that, The ratio of the distance (a) from the edge of the transparent conductive layer (201) to the center of the transparent conductive layer (201) to the distance (b) from the edge of the transparent conductive layer (201) to the edge of the first passivation layer (200) is 3:1 to 4:

1.

3. The light-emitting diode according to claim 1, characterized in that, The distance (c) between the edge of the second groove (1003) and the edge of the transparent conductive layer (201) is greater than 5 μm.

4. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The width of the first groove (1002) is 30-40 μm, the width of the second groove (1003) is 35-45 μm, and the width of the third groove (1004) is 40-50 μm.

5. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The thickness of the first passivation layer (200) is 800-1200 angstroms, the thickness of the second passivation layer (202) is 2800-3200 angstroms, and the thickness of the third passivation layer (203) is 1800-2200 angstroms.

6. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The thickness of the transparent conductive layer (201) is 2800–3200 angstroms.

7. A method for fabricating a light-emitting diode, characterized in that, The method includes: Fabrication of epitaxial structures; A first passivation layer is formed on the surface of the epitaxial structure, the first passivation layer having a first groove; A transparent conductive layer is fabricated, which is located on the first passivation layer and passes through the first groove to be connected to the epitaxial structure. There is a gap between the edge of the transparent conductive layer and the edge of the first passivation layer. A second passivation layer is fabricated, which is located on top of the first passivation layer and covers the gap and the edge of the transparent conductive layer. The second passivation layer has a second groove, the width of which is greater than the width of the first groove. A third passivation layer is fabricated, which is located on top of the second passivation layer. The third passivation layer has a third groove, the width of which is greater than the width of the second groove.

8. The method for fabricating a light-emitting diode according to claim 7, characterized in that, The ratio of the distance from the edge of the transparent conductive layer to the center of the transparent conductive layer to the distance from the edge of the transparent conductive layer to the edge of the first passivation layer is 3:1 to 4:

1.

9. The method for fabricating a light-emitting diode according to claim 7, characterized in that, The distance between the edge of the second groove and the edge of the transparent conductive layer is greater than 5 μm.

10. The method for fabricating a light-emitting diode according to any one of claims 7 to 9, characterized in that, The width of the first groove is 30-40 μm, the width of the second groove is 35-45 μm, and the width of the third groove is 40-50 μm.

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