Light emitting diode and method of manufacturing light emitting diode

Abstract

The present disclosure provides a light emitting diode and a light emitting diode preparation method. The light emitting diode comprises an epitaxial structure and a reflective layer; the reflective layer comprises a first film layer group, a second film layer group and a third film layer group which are sequentially stacked, the first film layer group comprises first material sublayers and second material sublayers which are alternately and sequentially stacked, the refractive index of the first material sublayer is lower than the refractive index of the second material sublayer, the second film layer group comprises a first adhesive layer, a high-reflection layer, a protective layer and a second adhesive layer which are sequentially stacked, and the third film layer group comprises first material sublayers and second material sublayers which are alternately and sequentially stacked.

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 a light-emitting diode. 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 reflective layer. The quality of the reflective layer directly affects the brightness of the LED.

[0004] The reflective layer is poorly stable and has low reflectivity, resulting in low LED brightness. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) and a method for fabricating an LED, which improves the stability of the reflective layer in the silver mirror structure of the LED, increases the reflectivity of the reflective layer for light, and improves the luminous brightness of the LED. The technical solution is as follows:

[0006] On one hand, a light-emitting diode is provided, the light-emitting diode comprising: an epitaxial structure and a reflective layer;

[0007] The reflective layer covers the epitaxial structure; the reflective layer includes a first film layer group, a second film layer group, and a third film layer group stacked sequentially, the first film layer group including a first material sublayer and a second material sublayer stacked alternately, the refractive index of the first material sublayer being lower than that of the second material sublayer, the second film layer group including a first adhesive layer, a high reflective layer, a protective layer, and a second adhesive layer stacked sequentially, and the third film layer group including the first material sublayer and the second material sublayer stacked alternately.

[0008] Optionally, the number of stacking periods of the first material sublayer and the second material sublayer in the first film layer group is 10 to 25, and the number of stacking periods of the first material sublayer and the second material sublayer in the third film layer group is 2 to 10.

[0009] Optionally, the first material sublayer is a silicon oxide sublayer, and the second material sublayer is a titanium oxide sublayer.

[0010] Optionally, in the first film layer group, the thickness of the first material sublayer is greater than the thickness of the second material sublayer; in the third film layer group, the thickness of the first material sublayer is less than the thickness of the second material sublayer.

[0011] Optionally, in the first film layer group, the thickness of the first material sublayer is 1000–4000 angstroms, and the thickness of the second material sublayer is 50–800 angstroms; in the third film layer group, the thickness of the first material sublayer is 50–800 angstroms, and the thickness of the second material sublayer is 1000–4000 angstroms.

[0012] Optionally, the first adhesive layer is a Ti layer, the high-reflectivity layer is an Ag layer, the protective layer is a Ni layer, and the second adhesive layer is a TiW layer.

[0013] On the other hand, a method for fabricating a light-emitting diode includes:

[0014] Fabrication of epitaxial structures;

[0015] A reflective layer is fabricated on the epitaxial structure. The reflective layer includes a first film layer group, a second film layer group, and a third film layer group stacked sequentially. The first film layer group includes a first material sublayer and a second material sublayer stacked alternately in sequence. The refractive index of the first material sublayer is lower than that of the second material sublayer. The second film layer group includes a first adhesive layer, a high-reflectivity layer, a protective layer, and a second adhesive layer stacked sequentially in sequence. The third film layer group includes the first material sublayer and the second material sublayer stacked alternately in sequence in sequence.

[0016] Optionally, the number of stacking periods of the first material sublayer and the second material sublayer in the first film layer group is 10 to 25, and the number of stacking periods of the first material sublayer and the second material sublayer in the third film layer group is 2 to 10.

[0017] Optionally, in the first film layer group, the thickness of the first material sublayer is greater than the thickness of the second material sublayer; in the third film layer group, the thickness of the first material sublayer is less than the thickness of the second material sublayer.

[0018] The beneficial effects of the technical solutions provided in this disclosure are:

[0019] In this embodiment, the reflective layer of the light-emitting diode uses a three-layer stacked structure. The first layer group comprises alternating layers of a first material sublayer and a second material sublayer. The refractive index of the first material sublayer is lower than that of the second material sublayer. This first layer group, composed of the first and second material sublayers, provides high reflectivity for specific wavelengths of light. The second layer group comprises alternating layers of a first adhesive layer, a high-reflectivity layer, a protective layer, and a second adhesive layer. This metal stack provides high reflectivity across the entire wavelength range, allowing for secondary reflection of light not reflected by the first layer group, and also ensures adhesion between the first and third layers. The third layer group comprises alternating layers of a first material sublayer and a second material sublayer. This third layer group effectively protects the second layer group and provides supplementary reflection for both the first and second layers. These three layer groups improve the stability of the reflective layer, increase its reflectivity, and enhance the LED's brightness. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0022] Figure 2 This is a schematic diagram of the structure of a reflective layer provided in an embodiment of this disclosure;

[0023] Figure 3 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure;

[0024] Figure 4 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure embodiment;

[0025] Figure 5 This is a schematic diagram showing the comparison of reflectance provided in the embodiments of this disclosure.

[0026] The attached figures are labeled as follows:

[0027] 10: Electrode structure; 100: Substrate; 101: First semiconductor layer; 102: Active layer; 103: Second semiconductor layer; 104: Transparent conductive layer; 105: First electrode; 106: Second electrode; 107: Reflective layer; 108: First electrode pad; 109: Second electrode pad; 110: First via; 111: Second via; 120: Step surface of stepped structure; 1000: Epitaxial structure; 200: First film layer group; 300: Second film layer group; 400: Third film layer group; 201: First material sublayer; 202: Second material sublayer; 301: First adhesive layer; 302: High reflectivity layer; 303: Protective layer; 304: Second adhesive layer. Detailed Implementation

[0028] 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.

[0029] 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 1000 and a reflective layer 107. The reflective layer 107 covers the epitaxial structure 1000.

[0030] Figure 2 This is a schematic diagram of the structure of a reflective layer provided in an embodiment of this disclosure. Figure 2 As shown, the reflective layer 107 includes a first film layer group 200, a second film layer group 300, and a third film layer group 400 stacked sequentially. The first film layer group 200 includes a first material sublayer 201 and a second material sublayer 202 stacked sequentially and alternately. The refractive index of the first material sublayer 201 is lower than that of the second material sublayer 202. The second film layer group 300 includes a first adhesive layer 301, a high reflectivity layer 302, a protective layer 303, and a second adhesive layer 304 stacked sequentially. The third film layer group 400 includes a first material sublayer 201 and a second material sublayer 202 stacked sequentially and alternately.

[0031] In this embodiment, the reflective layer of the light-emitting diode uses a three-layer stacked structure. The first layer group comprises alternating layers of a first material sublayer and a second material sublayer. The refractive index of the first material sublayer is lower than that of the second material sublayer. This first layer group, composed of the first and second material sublayers, provides high reflectivity for specific wavelengths of light. The second layer group comprises alternating layers of a first adhesive layer, a high-reflectivity layer, a protective layer, and a second adhesive layer. This metal stack provides high reflectivity across the entire wavelength range, allowing for secondary reflection of light not reflected by the first layer group, and also ensures adhesion between the first and third layers. The third layer group comprises alternating layers of a first material sublayer and a second material sublayer. This third layer group effectively protects the second layer group and provides supplementary reflection for both the first and second layers. These three layer groups improve the stability of the reflective layer, increase its reflectivity, and enhance the LED's brightness.

[0032] In this embodiment of the present disclosure, the first and third film layers in the reflective layer 107 are distributed Bragg reflector (DBR) layers. The first and third film layers reflect light and absorb almost no light.

[0033] In this embodiment of the disclosure, the number of cycles of the first film layer group 200 is greater than the number of cycles of the third film layer group 400.

[0034] For example, in the first film layer group 200, the number of stacking periods of the first material sublayer 201 and the second material sublayer 202 is 10 to 25, and in the third film layer group 400, the number of stacking periods of the first material sublayer 201 and the second material sublayer 202 is 2 to 10.

[0035] For example, the number of stacking periods of the first material sublayer 201 and the second material sublayer 202 in the first film layer group 200 is 20, and the number of stacking periods of the first material sublayer 201 and the second material sublayer 202 in the third film layer group 400 is 6.

[0036] In this implementation, the number of cycles of the first film layer group 200 is greater than the number of cycles of the third film layer group 400, that is, the thickness of the first film layer group 200 is greater than the thickness of the third film layer group 400. The greater the thickness of the DBR film, the higher the reflectivity. Therefore, using a thicker first film layer group 200 can improve the reflectivity of the first film layer group 200, reduce the amount of light absorbed by the second film layer, and decrease the LED light loss rate.

[0037] In this embodiment of the disclosure, the first material sublayer 201 can be a silicon oxide sublayer (e.g., SiO2), and the second material sublayer 202 can be a titanium oxide sublayer (e.g., Ti3O5, Ti2O3).

[0038] In this embodiment of the disclosure, the thickness of the first material sublayer 201 in the first film layer group 200 is greater than the thickness of the second material sublayer 202. This thickness design results in better reflectivity of the first film layer group.

[0039] In one example, the thickness of the first material sublayer 201 in the first film layer group 200 can be 1000 to 4000 angstroms, and the thickness of the second material sublayer 202 can be 50 to 800 angstroms.

[0040] For example, in the first film layer group 200, the thickness of the first material sublayer 201 is 2500 angstroms and the thickness of the second material sublayer 202 is 500 angstroms.

[0041] In this embodiment, the thickness of the first material sublayer 201 in the third film layer group 400 is less than the thickness of the second material sublayer 202. When the film system of the third film layer group is designed according to the thickness of the film system of the first film layer group, an abnormal appearance phenomenon of uneven color will appear on the chip surface (the DBR design of the second film layer group + the first film layer group has a mismatch in reflection superposition effect). When the thicknesses of the two material sublayers in the third film layer group and the first film layer group are designed to be opposite, the above problem can be improved, and the chip appearance will not have an abnormal uneven color.

[0042] In one example, the thickness of the first material sublayer 201 in the third film layer group 400 can be 50 to 800 angstroms, and the thickness of the second material sublayer 202 can be 1000 to 4000 angstroms.

[0043] For example, in the third film layer group 400, the thickness of the first material sublayer 201 is 400 angstroms and the thickness of the second material sublayer 202 is 2000 angstroms.

[0044] In this embodiment of the disclosure, the first adhesive layer 301 may be a Ti layer, and the thickness of the first adhesive layer 301 may be 5 to 1000 angstroms.

[0045] For example, the thickness of the first adhesive layer 301 can be 500 angstroms.

[0046] In this embodiment, the high reflectivity layer 302 can be an Ag layer, and the thickness of the high reflectivity layer 302 can be 500 to 2000 angstroms.

[0047] For example, the thickness of the high-reflectivity layer 302 can be 1000 angstroms.

[0048] In this embodiment of the disclosure, the protective layer 303 can be a Ni layer with a thickness of 200 to 1000 angstroms.

[0049] For example, the protective layer 303 can be 600 angstroms thick.

[0050] In this embodiment of the disclosure, the second adhesive layer 304 can be a TiW layer, and the thickness of the second adhesive layer 304 can be 5 to 1000 angstroms.

[0051] For example, the thickness of the second adhesive layer 304 can be 500 angstroms.

[0052] In this implementation, the second film layer group is formed using the aforementioned materials and thickness, which can ensure both the reflection effect and the adhesion effect.

[0053] like Figure 1 As shown, the light-emitting diode also includes a substrate 100, and an epitaxial structure 1000 is located on the substrate 100.

[0054] In the embodiments of this disclosure, the substrate 100 can be any one of sapphire substrate, Si substrate, SiC substrate, etc., and this disclosure does not limit the material of the substrate.

[0055] For example, substrate 100 is a sapphire substrate.

[0056] For example, the epitaxial structure 1000 includes a first semiconductor layer 101, an active layer 102 and a second semiconductor layer 103 stacked sequentially, the first semiconductor layer 101, the active layer 102 and the second semiconductor layer 103 forming a stepped structure, and a reflective layer 107 covering the stepped structure.

[0057] 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.

[0058] 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.

[0059] In another example, the first semiconductor layer 101 can be a P-type semiconductor layer and the second semiconductor layer 103 can be an N-type semiconductor layer.

[0060] 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.

[0061] Optionally, the light-emitting diode further includes an electrode structure 10, which includes a first electrode structure and a second electrode structure. The first electrode structure passes through the reflective layer 107 and is connected to the first semiconductor layer 101, and the second electrode structure passes through the reflective layer 107 and is connected to the second semiconductor layer 103.

[0062] In this embodiment of the disclosure, the first electrode structure includes a first electrode 105 and a first electrode pad 108, and the second electrode structure includes a second electrode 106 and a second electrode pad 109.

[0063] The first electrode 105 is located on the stepped surface 120, the second electrode 106 is located on the surface of the second semiconductor layer 103, the first electrode pad 108 penetrates the reflective layer 107 and is connected to the first electrode 105, and the second electrode pad 109 penetrates the reflective layer 107 and is connected to the second electrode 106.

[0064] In this embodiment of the disclosure, both the first electrode pad 108 and the second electrode pad 109 may include a Cr layer, an Al layer, a Ti layer, a Ni layer and an Au alloy layer stacked sequentially.

[0065] In one example, the thickness of the Cr layer is 80–120 nm, the thickness of the Al layer is 2500–3500 nm, the thickness of the Ti layer is 450–550 nm, the thickness of the Ni layer is 1800–2200 nm, and the thickness of the Au alloy layer is 18000–22000 nm.

[0066] For example, the thickness of the Cr layer is 100 nm, the thickness of the Al layer is 3000 nm, the thickness of the Ti layer is 500 nm, the thickness of the Ni layer is 2000 nm, and the thickness of the Au alloy layer is 20000 nm.

[0067] In one example, the first electrode structure can be an N-electrode structure, including an N-electrode and an N-electrode pad; the second electrode structure can be a P-electrode structure, including a P-electrode and a P-electrode pad.

[0068] In another example, the first electrode structure can be a P electrode structure, and the second electrode structure can be an N electrode structure.

[0069] In other examples, the first or second electrode structure may include only electrode pads and not electrodes. For example, when the first electrode structure is an N-electrode structure, it may include only N-electrode pads, and this disclosure does not impose any limitations on this. It is worth noting that if the first electrode structure includes only N-electrode pads, the material of the N-electrode pads needs to be selectively chosen to ensure good ohmic contact between the first electrode structure and the first semiconductor layer.

[0070] Optionally, the light-emitting diode may further include a transparent conductive layer 104, which is located between the epitaxial structure 1000 and the second electrode 106, for example, between the surface of the second semiconductor layer 103 and the second electrode 106.

[0071] In this embodiment of the disclosure, the transparent conductive layer 104 can be an indium tin oxide (ITO) layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.

[0072] 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.

[0073] Figure 3 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 3 The method includes the following steps:

[0074] S11. Fabricate the extensional structure.

[0075] S12. A reflective layer is fabricated on the epitaxial structure. The reflective layer includes a first film layer group, a second film layer group, and a third film layer group stacked sequentially. The first film layer group includes a first material sublayer and a second material sublayer stacked alternately in sequence. The refractive index of the first material sublayer is lower than that of the second material sublayer. The second film layer group includes a first adhesive layer, a high reflective layer, a protective layer, and a second adhesive layer stacked sequentially in sequence. The third film layer group includes a first material sublayer and a second material sublayer stacked alternately in sequence in sequence.

[0076] In this embodiment, the reflective layer of the light-emitting diode uses a three-layer stacked structure. The first layer group comprises alternating layers of a first material sublayer and a second material sublayer. The refractive index of the first material sublayer is lower than that of the second material sublayer. This first layer group, composed of the first and second material sublayers, provides high reflectivity for specific wavelengths of light. The second layer group comprises alternating layers of a first adhesive layer, a high-reflectivity layer, a protective layer, and a second adhesive layer. This metal stack provides high reflectivity across the entire wavelength range, allowing for secondary reflection of light not reflected by the first layer group, and also ensures adhesion between the first and third layer groups. The third layer group comprises alternating layers of a first material sublayer and a second material sublayer. This third layer group effectively protects the second layer group and provides supplementary reflection for both the first and second layer groups. These three layer groups improve the stability of the reflective layer, increase its reflectivity, and enhance the LED's brightness.

[0077] Figure 4 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure. See also... Figure 4 The method includes the following steps:

[0078] S21. A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially formed on a substrate, wherein the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial structure.

[0079] In one example, step S21 includes:

[0080] The first step is to fabricate the first semiconductor layer.

[0081] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.

[0082] The second step is to create the active layer.

[0083] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0084] The third step is to fabricate the second semiconductor layer.

[0085] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.

[0086] In the embodiments disclosed herein, the substrate can be any one of a sapphire substrate, a Si substrate, etc., for example, a sapphire substrate.

[0087] For example, the first semiconductor layer, the active layer, and the second semiconductor layer are fabricated using a metal-organic chemical vapor deposition (MOCVD) apparatus.

[0088] S22. The first semiconductor layer, the active layer and the second semiconductor layer are patterned to form a stepped structure.

[0089] In one example, step S22 includes:

[0090] Etching techniques are used to pattern the sequentially stacked first semiconductor layer, active layer, and second semiconductor layer to form a stepped structure.

[0091] In this embodiment of the disclosure, the stepped surface of the stepped structure is located in the first semiconductor layer.

[0092] S23. Fabricate a transparent conductive layer on the epitaxial structure.

[0093] For example, the transparent conductive layer is located on the surface of the second semiconductor layer of the epitaxial structure.

[0094] In this embodiment, the transparent conductive layer can be an ITO layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.

[0095] S24. Fabricate a first electrode and a second electrode, with the first electrode located on the stepped surface and the second electrode located on the surface of the transparent conductive layer.

[0096] In one example, step S24 includes:

[0097] A first electrode is formed on the step surface of the first semiconductor layer and a second electrode is formed on the surface of the transparent conductive layer using electron beam evaporation or magnetron sputtering technology.

[0098] S25. Fabricate a reflective layer, which covers a stepped structure, a transparent conductive layer, a first electrode, and a second electrode.

[0099] In one example, step S25 includes:

[0100] In this embodiment of the present disclosure, the reflective layer includes a first film layer group, a second film layer group, and a third film layer group stacked sequentially. The first film layer group includes a first material sublayer and a second material sublayer stacked sequentially and alternately. The second film layer group includes a first adhesive layer, a high reflective layer, a protective layer, and a second adhesive layer stacked sequentially. The third film layer group includes a first material sublayer and a second material sublayer stacked sequentially and alternately.

[0101] In the embodiments disclosed herein, the number of stacking periods of the first material sublayer and the second material sublayer in the first film layer group is 10 to 25, and the number of stacking periods of the first material sublayer and the second material sublayer in the third film layer group is 2 to 10.

[0102] For example, the number of stacking periods of the first material sublayer and the second material sublayer in the first film layer group is 20, and the number of stacking periods of the first material sublayer and the second material sublayer in the third film layer group is 6.

[0103] In this implementation, the number of cycles of the first film layer group is greater than the number of cycles of the third film layer group, that is, the thickness of the first film layer group is greater than the thickness of the third film layer group. The greater the thickness of the DBR film, the higher the reflectivity. Therefore, using a thicker first film layer group can improve the reflectivity of the first film layer group, reduce the amount of light absorbed by the second film layer, and decrease the LED light loss rate.

[0104] In the embodiments disclosed herein, the first material sublayer may be a silicon oxide sublayer (e.g., SiO2), and the second material sublayer may be a titanium oxide sublayer (e.g., Ti3O5, Ti2O3).

[0105] In this embodiment of the disclosure, the thickness of the first material sublayer in the first film layer group is greater than the thickness of the second material sublayer. This thickness design results in better reflectivity of the first film layer group.

[0106] In one example, the thickness of the first material sublayer in the first film layer group can be 1000 to 4000 angstroms, and the thickness of the second material sublayer can be 50 to 800 angstroms.

[0107] For example, the thickness of the first material sublayer in the first film layer group is 2500 angstroms and the thickness of the second material sublayer is 500 angstroms.

[0108] In this embodiment, the thickness of the first material sublayer in the third film layer group is less than the thickness of the second material sublayer. When the film system of the third film layer group is designed according to the thickness of the film system of the first film layer group, an abnormal appearance phenomenon of uneven color will appear on the chip surface (the DBR design of the second film layer group + the first film layer group has a mismatch in reflection superposition effect). When the thicknesses of the two material sublayers in the third film layer group and the first film layer group are reversed, the above problem can be improved, and the chip appearance will not have an abnormal uneven color.

[0109] In one example, the thickness of the first material sublayer in the third film layer group can be 50 to 800 angstroms, and the thickness of the second material sublayer can be 1000 to 4000 angstroms.

[0110] For example, in the third film layer group, the thickness of the first material sublayer is 400 angstroms and the thickness of the second material sublayer is 2000 angstroms.

[0111] In this embodiment of the disclosure, the first adhesive layer may be a Ti layer, and the thickness of the first adhesive layer may be 5 to 1000 angstroms.

[0112] For example, the thickness of the first adhesive layer can be 500 angstroms.

[0113] In this embodiment, the high-reflectivity layer can be an Ag layer, and the thickness of the high-reflectivity layer can be 500 to 2000 angstroms.

[0114] For example, the thickness of the high-reflectivity layer can be 1000 angstroms.

[0115] In this embodiment of the disclosure, the protective layer can be a Ni layer, and the thickness of the protective layer can be 200 to 1000 angstroms.

[0116] For example, the protective layer thickness can be 600 angstroms.

[0117] In this embodiment of the disclosure, the second adhesive layer may be a TiW layer, and the thickness of the second adhesive layer may be 5 to 1000 angstroms.

[0118] For example, the thickness of the second adhesive layer can be 500 angstroms.

[0119] In this embodiment, the first and third film layers are fabricated using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD) techniques. The second film layer is fabricated using evaporation or sputtering processes.

[0120] S26. Fabricate a first electrode pad and a second electrode pad, wherein the first electrode pad penetrates the reflective layer and is connected to the first electrode, and the second electrode pad penetrates the reflective layer and is connected to the second electrode.

[0121] In one example, step S26 includes:

[0122] The first step is to pattern the reflective layer to form the first and second through holes.

[0123] The first through-hole penetrates the reflective layer and connects to the first electrode, while the second through-hole penetrates the reflective layer and connects to the second electrode.

[0124] The second step is to create the first electrode pad and the second electrode pad.

[0125] The first electrode pad and the second electrode pad are fabricated using electron beam evaporation or magnetron sputtering techniques.

[0126] In this embodiment of the disclosure, the first electrode pad and the second electrode pad include a Cr layer, an Al layer, a Ti layer, a Ni layer and an Au alloy layer stacked sequentially.

[0127] In one example, the thickness of the Cr layer is 80–120 nm, the thickness of the Al layer is 2500–3500 nm, the thickness of the Ti layer is 450–550 nm, the thickness of the Ni layer is 1800–2200 nm, and the thickness of the Au alloy layer is 18000–22000 nm.

[0128] For example, the thickness of the Cr layer is 100 nm, the thickness of the Al layer is 3000 nm, the thickness of the Ti layer is 500 nm, the thickness of the Ni layer is 2000 nm, and the thickness of the Au alloy layer is 20000 nm.

[0129] In this embodiment of the disclosure, the first electrode and the first electrode pad form a first electrode structure, and the second electrode and the second electrode pad form a second electrode structure.

[0130] S27. Fabricate a passivation layer, which covers the surface of the reflective layer.

[0131] In one example, step S27 includes:

[0132] A SiO2 layer is fabricated on the surface of the stepped structure using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD) techniques to form a passivation layer.

[0133] In the embodiments disclosed herein, the passivation layer may also be a transparent insulating material such as Al2O3, and the material of the passivation layer is not limited in this disclosure.

[0134] Figure 5 This is a schematic diagram comparing the reflectivity of a light-emitting diode provided in this embodiment with that of a light-emitting diode provided in related technologies. For example... Figure 5 As shown, the X-axis represents the incident angle of light, and the Y-axis represents the reflectivity. The conventional DBR scheme is a related technology, while the novel DBR scheme is an embodiment of this disclosure. It can be seen that the structure provided in this embodiment significantly improves reflectivity when the angle is around 50 degrees. Therefore, the overall reflectivity of the light-emitting diode provided in this application is better than that of the light-emitting diodes provided by related technologies.

[0135] 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 (1000) and a reflective layer (107); The reflective layer (107) covers the epitaxial structure (1000); the reflective layer (107) includes a first film layer group (200), a second film layer group (300) and a third film layer group (400) stacked sequentially. The first film layer group (200) includes a first material sublayer (201) and a second material sublayer (202) stacked sequentially and alternately. The refractive index of the first material sublayer (201) is lower than that of the second material sublayer (202). The second film layer group (300) includes a first adhesive layer (301), a high reflective layer (302), a protective layer (303) and a second adhesive layer (304) stacked sequentially. The third film layer group (400) includes the first material sublayer (201) and the second material sublayer (202) stacked sequentially and alternately. The first adhesive layer (301) is a Ti layer, the high reflectivity layer (302) is an Ag layer, the protective layer (303) is a Ni layer, and the second adhesive layer (304) is a TiW layer; The number of stacking cycles of the first material sublayer (201) and the second material sublayer (202) in the first film layer group (200) is 20, and the number of stacking cycles of the first material sublayer (201) and the second material sublayer (202) in the third film layer group (400) is 6; In the first film layer group (200), the thickness of the first material sublayer (201) is 2500 angstroms and the thickness of the second material sublayer (202) is 500 angstroms; in the third film layer group (400), the thickness of the first material sublayer (201) is 400 angstroms and the thickness of the second material sublayer (202) is 2000 angstroms.

2. The light-emitting diode according to claim 1, characterized in that, The first material sublayer (201) is a silicon oxide sublayer, and the second material sublayer (202) is a titanium oxide sublayer.

3. The light-emitting diode according to claim 1 or 2, characterized in that, The first adhesive layer (301) has a thickness of 5 to 1000 angstroms, the high reflectivity layer (302) has a thickness of 500 to 2000 angstroms, the protective layer (303) has a thickness of 200 to 1000 angstroms, and the second adhesive layer (304) has a thickness of 5 to 1000 angstroms.

4. A method for fabricating a light-emitting diode, characterized in that, The method includes: Fabrication of epitaxial structures; A reflective layer is fabricated on the epitaxial structure. The reflective layer comprises a first film layer group, a second film layer group, and a third film layer group stacked sequentially. The first film layer group comprises a first material sublayer and a second material sublayer stacked alternately, with the refractive index of the first material sublayer being lower than that of the second material sublayer. The second film layer group comprises a first adhesion layer, a high-reflectivity layer, a protective layer, and a second adhesion layer stacked sequentially. The third film layer group comprises the first material sublayer and the second material sublayer stacked alternately, with the first adhesion layer being a Ti layer, the high-reflectivity layer being an Ag layer, the protective layer being a Ni layer, and the second adhesion layer being a TiW layer. The number of stacking periods for the first and second material sublayers in the first film layer group is 20, and the number of stacking periods for the first and second material sublayers in the third film layer group is 6. The thickness of the first material sublayer in the first film layer group is 2500 angstroms, and the thickness of the second material sublayer is 500 angstroms. The thickness of the first material sublayer in the third film layer group is 400 angstroms, and the thickness of the second material sublayer is 2000 angstroms.

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