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 dielectric layer and a reflecting layer, the epitaxial structure comprises a first surface and a second surface opposite to the first surface; the dielectric layer is located on the first surface of the epitaxial structure, the edge of the first surface of the epitaxial structure is provided with a first step, and the reflecting layer covers the dielectric layer, the first surface of the epitaxial structure and the first step. The epitaxial structure comprises a first surface and a second surface opposite to the first surface, a first step is arranged on the first surface of the edge of the epitaxial structure, and then a dielectric layer, the first surface and the first step of the epitaxial structure are wrapped by a reflecting layer, so that water vapor is difficult to enter from the reflecting layer; the side wall of the epitaxial structure can be effectively prevented from being corroded by acid gas in the high-temperature and high-humidity loading process, and the yield of the light-emitting diode is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of light-emitting devices, and in particular to a light-emitting diode and a method for preparing the same. Background Art

[0002] Light Emitting Diode (LED) is a semiconductor device that can emit light. It has the advantages of energy saving, high brightness, high durability, long life and light weight. It has been widely used in fields such as lighting and display.

[0003] The related art provides a light emitting diode, which includes an epitaxial structure, a dielectric layer, a reflective layer and a protective layer, wherein the dielectric layer is located in the epitaxial structure, the reflective layer covers the dielectric layer, and the protective layer covers the side of the epitaxial structure.

[0004] In the above-mentioned light-emitting diode structure, although a protective layer is designed, water vapor can still enter from the contact surface between the dielectric layer and the epitaxial structure, causing the dielectric layer and the epitaxial structure to separate and reduce the reliability of the light-emitting diode. Summary of the invention

[0005] The disclosed embodiment provides a light emitting diode and a method for manufacturing the same, which can significantly improve the problem of the side wall of the epitaxial structure being corroded by acidic gas during high temperature and high humidity load, resulting in dimming or dead lamp beads. The technical solution is as follows:

[0006] In one aspect, a light emitting diode is provided, the light emitting diode comprising: an epitaxial structure, a dielectric layer and a reflective layer;

[0007] The epitaxial structure includes a first surface and a second surface opposite to the first surface;

[0008] The dielectric layer is located on the first surface of the epitaxial structure, a first step is provided at the edge of the first surface of the epitaxial structure, and the reflective layer covers the dielectric layer, the first surface of the epitaxial structure and the first step.

[0009] Optionally, the epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, the second semiconductor layer having a first surface close to the active layer, and a second surface away from the active layer; the second surface of the second semiconductor layer is the first surface of the epitaxial structure, and the height of the first step is less than half the thickness of the second semiconductor layer.

[0010] Optionally, the reflective layer extends from a side surface of the epitaxial structure to form a second step, and a width of the first step is equal to a width of the second step.

[0011] Optionally, the light emitting diode further includes a protection layer, wherein the protection layer covers the second surface of the epitaxial structure, the side surface of the epitaxial structure and the second step.

[0012] Optionally, the thickness of the protection layer is less than or equal to the width of the second step.

[0013] Optionally, the light emitting diode further comprises: a substrate, a transfer layer, a first electrode and a second electrode;

[0014] The reflective layer is connected to one side of the substrate through the transfer layer, the second surface of the epitaxial structure is connected to the first electrode, and the other side of the substrate is connected to the second electrode.

[0015] In another aspect, a method for preparing a light emitting diode comprises:

[0016] Manufacturing an epitaxial structure, the epitaxial structure comprising a first surface and a second surface opposite to the first surface;

[0017] Fabricating a dielectric layer on the first surface of the epitaxial structure;

[0018] A first step is provided at an edge of the first surface of the epitaxial structure;

[0019] A reflective layer is manufactured, wherein the reflective layer covers the dielectric layer, the first surface of the epitaxial structure, and the first step.

[0020] Optionally, the epitaxial structure includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence, the second semiconductor layer is located on a first surface of the epitaxial structure, and a height of the first step is less than half of a thickness of the second semiconductor layer.

[0021] Optionally, the method further comprises:

[0022] The epitaxial structure is patterned so that the reflective layer extends from a side surface of the epitaxial structure to form a second step, and the width of the first step is equal to the width of the second step.

[0023] Optionally, the method further comprises:

[0024] A protection layer is manufactured, wherein the protection layer covers the second surface of the epitaxial structure, the side surface of the epitaxial structure and the second step.

[0025] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0026] In the embodiment of the present disclosure, the epitaxial structure includes a first surface and a second surface opposite to the first surface. A first step is opened on the first surface at the edge of the epitaxial structure, and then the dielectric layer, the first surface and the first step of the epitaxial structure are wrapped by a reflective layer, so that it is difficult for water vapor to enter through the reflective layer. This can effectively prevent the side wall of the epitaxial structure from being corroded by acidic gases during high temperature and high humidity load, thereby improving the yield of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 is a structural schematic diagram of a light emitting diode provided by an embodiment of the present disclosure;

[0029] Figure 2 is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure;

[0030] Figure 3 is a flow chart of another method for preparing a light emitting diode provided by an embodiment of the present disclosure;

[0031] Figure 4 This is a structural schematic diagram of a light emitting diode manufacturing process provided by an embodiment of the present disclosure;

[0032] Figure 5 This is a structural schematic diagram of a light emitting diode manufacturing process provided by an embodiment of the present disclosure;

[0033] Figure 6 This is a structural schematic diagram of a light emitting diode manufacturing process provided by an embodiment of the present disclosure;

[0034] Figure 7 It is a structural schematic diagram of a light emitting diode manufacturing process provided by an embodiment of the present disclosure.

[0035] The reference numerals are as follows:

[0036] 10: epitaxial structure;

[0037] 100: substrate; 101: dielectric layer; 102: reflective layer; 103: protective layer; 104: first semiconductor layer; 105: active layer; 106: second semiconductor layer; 107: transfer layer; 108: first electrode; 109: second electrode;

[0038] 201: First step; 202: Second step;

[0039] 301: Temporary substrate;

[0040] H: height of the first step; W1: width of the first step; W2: width of the second step. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0042] Figure 1 is a schematic diagram of the structure of a light emitting diode provided by an embodiment of the present disclosure. Figure 1 , the light emitting diode comprises: an epitaxial structure 10, a dielectric layer 101 and a reflective layer 102;

[0043] The epitaxial structure 10 includes a first surface and a second surface opposite to the first surface;

[0044] The dielectric layer 101 is located on the first surface of the epitaxial structure 10 . A first step 201 is provided at the edge of the first surface of the epitaxial structure 10 . The reflective layer 102 covers the dielectric layer 101 , the first surface of the epitaxial structure 10 and the first step 201 .

[0045] In the embodiment of the present disclosure, the epitaxial structure includes a first surface and a second surface opposite to the first surface. A first step is opened on the first surface at the edge of the epitaxial structure, and then the dielectric layer, the first surface and the first step of the epitaxial structure are wrapped by a reflective layer, so that it is difficult for water vapor to enter from the reflective layer, which can effectively prevent the side wall of the epitaxial structure from being corroded by acidic gases during high temperature and high humidity load, thereby improving the yield of the light-emitting diode.

[0046] In the embodiment of the present disclosure, the dielectric layer 101 may be a SiO 2 dielectric layer.

[0047] exist Figure 1 In an implementation manner, the dielectric layer 101 is a dielectric layer having through holes.

[0048] In other implementations, the dielectric layer 101 may not be patterned with through holes and may be in a complete shape, and the reflective layer 102 is connected to the epitaxial structure via the first step 201. This method simplifies the manufacturing process while ensuring water vapor protection.

[0049] In the embodiment of the present disclosure, the epitaxial structure 10 may include a first semiconductor layer 104 , an active layer 105 , and a second semiconductor layer 106 which are sequentially stacked.

[0050] The first semiconductor layer 104 includes an N-type AlGaInP current spreading layer and an N-type AlInP carrier confinement layer stacked in sequence.

[0051] In the disclosed embodiment, the growth of the semiconductor layer can be achieved by using VeecoK465i or C4 or RB metal organic chemical vapor deposition (MOCVD) equipment or AIXTRON metal organic chemical vapor deposition equipment. High purity H2 (hydrogen) or high purity N2 (nitrogen) or a mixture of high purity H2 and high purity N2 is used as a carrier gas, high purity NH3 is used as an N source, trimethyl gallium (TMGa) and triethyl gallium (TEGa) are used as gallium sources, trimethyl indium (TMIn) is used as an indium source, silane (SiH4) is used as an N-type dopant, trimethylaluminum (TMAl) is used as an aluminum source, bis(cyclopentadienyl) magnesium (CP2Mg) is used as a P-type dopant, arsine (AsH3) is used as an arsenic source, and phosphine (PH3) is used as a phosphorus source.

[0052] In the embodiment of the present disclosure, the first semiconductor layer 104 may further include an etching stop layer located on the surface of the N-type AlGaInP current spreading layer, and the etching medium layer may be a solidified phosphoric acid mixture.

[0053] In the embodiment of the present disclosure, the active layer 105 is a multi-quantum well layer, including a plurality of periodically alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0054] In the embodiment of the present disclosure, the second semiconductor layer 106 includes a P-type AlInP carrier confinement layer and a P-type GaP window layer stacked in sequence.

[0055] Exemplarily, a P-type GaP window layer and a P-type AlInP carrier confinement layer are sequentially fabricated on the surface of the active layer using a Metal Organic Chemical Vapor Deposition (MOCVD) device.

[0056] In the embodiment of the present disclosure, the reflective layer 102 may be an AuZn metal reflective layer. AuZn has high reflectivity and good corrosion resistance, and can block water vapor corrosion while ensuring reflectivity, thereby improving the yield of the light-emitting diode.

[0057] In other implementations, the reflective layer 102 may also be an Ag metal reflective layer, or an Au metal reflective layer. In other implementations, the reflective layer 102 may also be a stack of Ag and Au, or a stack of Ag and TiW.

[0058] In the embodiment of the present disclosure, the protective layer 103 may be a SiN protective layer. SiN has excellent chemical stability and corrosion resistance, and can effectively prevent water, oxygen and other media from corroding the substrate material, thereby improving the reliability and stability of the device. In addition, the SiN protective layer also has high hardness and good resistance to water vapor penetration, which can prevent water vapor corrosion and improve the yield of the light-emitting diode.

[0059] In the embodiment of the present disclosure, the second semiconductor layer 106 has a first surface close to the active layer 105 and a second surface away from the active layer 105; the second surface of the second semiconductor layer 106 is the first surface of the epitaxial structure 10, and the height H of the first step 201 is less than half the thickness of the second semiconductor layer 106.

[0060] In this implementation, the height of the first step will not be too high, so as to avoid electrical anomalies caused by insufficient thickness of the second semiconductor layer surface (GaP) failing to prevent metal transition of the reflective layer.

[0061] Exemplarily, the height H of the first step 201 is 1 / 4 to 1 / 3 of the thickness of the second semiconductor layer 106 .

[0062] The height H of the first step 201 is designed to be 1 / 4 to 1 / 3 of the thickness of the second semiconductor layer 106 , so that the first step 201 is not too low to allow water vapor to easily enter.

[0063] In the embodiment of the present disclosure, the reflective layer 102 extends from the side of the epitaxial structure 10 to form a second step 202. The width W1 of the first step 201 is equal to the width W2 of the second step 202, which can ensure that the first step has a sufficient path to block the entry of water vapor, and the second step has a sufficient area to fit the protective layer. In addition, due to the existence of the first step and the second step, the side wall of the epitaxial structure can be effectively prevented from being corroded by acidic gas during high temperature and high humidity loading, thereby improving the yield of the light-emitting diode.

[0064] In other implementations, the width W1 of the first step 201 may also be smaller than or larger than the width W2 of the second step 202 .

[0065] In the disclosed embodiment, the light-emitting diode further includes: a protective layer 103, the protective layer 103 covers the second surface of the epitaxial structure 10, the side surface of the epitaxial structure 10 and the second step 202. The protective layer and the reflective layer together form a protective structure of the epitaxial structure, and due to the presence of the first step and the second step, it is difficult for water vapor to enter from the contact surface of the reflective layer and the protective layer, which can effectively prevent the side wall of the epitaxial structure from being corroded by acidic gas during high temperature and high humidity loading, thereby improving the yield of the light-emitting diode.

[0066] In the embodiment of the present disclosure, the thickness of the protective layer 103 is less than or equal to the width W2 of the second step 202, so as to ensure that the second step has enough area to fit with the protective layer.

[0067] In the embodiment of the present disclosure, the light emitting diode may further include: a substrate 100 , a transfer layer 107 , a first electrode 108 and a second electrode 109 .

[0068] Exemplarily, the reflective layer 102 is connected to one side of the substrate 100 through the transfer layer 107, the second surface of the epitaxial structure 10 is connected to the first electrode 108, and the other side of the substrate 100 is connected to the second electrode 109. The light-emitting diode facilitates the manufacture of the epitaxial structure through the transfer layer, and the arrangement of the first electrode and the second electrode can enable the light-emitting diode to form good electrical conduction, thereby improving the light-emitting diode yield.

[0069] In the embodiment of the present disclosure, the substrate 100 may be a Si substrate.

[0070] In the embodiment of the present disclosure, the transfer layer 107 may be an Au transfer layer, or a transfer layer formed by a combination of Au and In, or a transfer layer formed by a combination of Ni and Sn.

[0071] In the embodiment of the present disclosure, the first electrode 108 and the second electrode 109 may be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0072] Exemplarily, the first electrode 108 and the second electrode 109 are stacked layers of Cr, Al, AlCu, Ti, Ni, Pt, and Au.

[0073] It is worth noting that in the embodiments of the present disclosure, structures may be selectively increased or decreased based on the structure of the above-mentioned light emitting diode, and the present disclosure does not impose any limitation on this.

[0074] Figure 2 is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 2 The method steps include:

[0075] S11. Fabricate an epitaxial structure, wherein the epitaxial structure includes a first surface and a second surface opposite to the first surface.

[0076] S12, fabricating a dielectric layer on the first surface of the epitaxial structure.

[0077] S13, a first step is provided at an edge of the first surface of the epitaxial structure.

[0078] S14. The reflective layer covers the dielectric layer, the first surface of the epitaxial structure, and the first step.

[0079] In the embodiment of the present disclosure, the epitaxial structure includes a first surface and a second surface opposite to the first surface. A first step is opened on the first surface at the edge of the epitaxial structure, and then the dielectric layer, the first surface and the first step of the epitaxial structure are wrapped by a reflective layer, so that it is difficult for water vapor to enter from the reflective layer, which can effectively prevent the side wall of the epitaxial structure from being corroded by acidic gases during high temperature and high humidity load, thereby improving the yield of the light-emitting diode.

[0080] Figure 3 is a flow chart of another method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 3 The method steps include:

[0081] S21. Forming a first semiconductor layer, an active layer, and a second semiconductor layer in sequence on a temporary substrate, wherein the second semiconductor layer, the active layer, and the first semiconductor layer constitute an epitaxial structure.

[0082] In one example, step S21 includes:

[0083] In the first step, a first semiconductor layer is formed on a temporary substrate.

[0084] The temporary substrate may be a GaAs substrate.

[0085] In the embodiment of the present disclosure, the first semiconductor layer includes an N-type AlGaInP current spreading layer and an N-type AlInP carrier confinement layer stacked in sequence.

[0086] In the disclosed embodiment, the growth of the semiconductor layer can be realized by using Veeco K465i or C4 or RB MOCVD equipment or AIXTRON metal organic compound chemical vapor deposition equipment. High purity H2 (hydrogen) or high purity N2 (nitrogen) or a mixture of high purity H2 and high purity N2 is used as a carrier gas, high purity NH3 is used as an N source, trimethyl gallium (TMGa) and triethyl gallium (TEGa) are used as gallium sources, trimethyl indium (TMIn) is used as an indium source, silane (SiH4) is used as an N-type dopant, trimethyl aluminum (TMAl) is used as an aluminum source, bis(cyclopentadienyl) magnesium (CP2Mg) is used as a P-type dopant, arsine (AsH3) is used as an arsenic source, and phosphine (PH3) is used as a phosphorus source.

[0087] Exemplarily, an N-type AlGaInP current spreading layer and an N-type AlInP carrier confinement layer are sequentially fabricated on a temporary substrate using MOCVD equipment.

[0088] In the disclosed embodiment, an etching stop layer may be formed on the N-type AlGaInP current spreading layer and the temporary substrate, and the etching medium layer is a solidified phosphoric acid mixture.

[0089] The second step is to make the active layer.

[0090] In the embodiment of the present disclosure, the active layer is a multi-quantum well layer, including a plurality of periodically alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0091] Exemplarily, a plurality of AlGaInP quantum well layers and AlGaInP quantum barrier layers are alternately grown on the surface of the first semiconductor layer using MOCVD equipment.

[0092] The third step is to make the second semiconductor layer.

[0093] In the embodiment of the present disclosure, the second semiconductor layer includes a P-type AlInP carrier confinement layer and a P-type GaP window layer.

[0094] Exemplarily, a P-type GaP window layer and a P-type AlInP carrier confinement layer are sequentially formed on the surface of the active layer using MOCVD equipment.

[0095] S22, fabricating a dielectric layer on the first surface of the epitaxial structure.

[0096] In the embodiment of the present disclosure, the dielectric layer may be a SiO2 dielectric layer.

[0097] Exemplarily, step S22 may include: manufacturing a dielectric film layer on the first surface of the epitaxial structure; and performing patterning on the dielectric film layer to obtain a dielectric layer.

[0098] In one example, the dielectric film layer is patterned, including:

[0099] In the first step, a photoresist mask layer is formed on the dielectric layer; the photoresist mask layer is provided with through holes corresponding to the pattern of the dielectric layer.

[0100] In the second step, the dielectric layer is corroded by a corrosive solution under the protection of the photoresist mask layer to form a through hole.

[0101] The third step is to remove the photoresist mask layer and spin dry.

[0102] In the above implementation, the dielectric layer is a dielectric layer having through holes.

[0103] In other implementations, the dielectric layer may not be patterned with through holes and may be in a complete shape, and the reflective layer is connected to the epitaxial structure via the first step. This method simplifies the manufacturing process while ensuring water vapor protection.

[0104] Figure 4 Schematic diagram of a light emitting diode manufacturing process provided by the embodiment of the present disclosure. Figure 4The first semiconductor layer 104, the active layer 105 and the second semiconductor layer 106 are sequentially stacked on the temporary substrate 301 to form an epitaxial structure 10. The dielectric layer 101 is grown on the first surface of the epitaxial structure 10. The dielectric layer 101 has a pattern consisting of a plurality of through holes.

[0105] S23, opening a first step at an edge of the first surface of the epitaxial structure, wherein a bottom surface of the first step is located in the second semiconductor layer.

[0106] In the embodiment of the present disclosure, the second semiconductor layer is located on the first surface of the epitaxial structure, and the etching depth of the first isolation groove is less than half of the thickness of the second semiconductor layer.

[0107] In this implementation, the height of the first step will not be too high, so as to avoid electrical anomalies caused by insufficient thickness of the second semiconductor layer surface (GaP) failing to prevent metal transition of the reflective layer.

[0108] Exemplarily, the height of the first step is 1 / 4 to 1 / 3 of the thickness of the second semiconductor layer.

[0109] The height of the first step is designed to be 1 / 4 to 1 / 3 of the thickness of the second semiconductor layer, so that the first step will not be too low to allow water vapor to easily enter.

[0110] In an embodiment of the present disclosure, a method for forming a first step in an epitaxial structure may include: making a photoresist mask; performing a patterning process on the epitaxial structure under the protection of the photoresist mask; and removing the photoresist mask.

[0111] S24, manufacturing a reflective layer on the epitaxial structure, wherein the reflective layer covers the dielectric layer, the first surface and the first step of the epitaxial structure.

[0112] In the disclosed embodiment, the reflective layer is grown by electron beam evaporation equipment, which can provide a coating with a high deposition rate, high density and high purity.

[0113] Figure 5 Schematic diagram of a light emitting diode manufacturing process provided by the embodiment of the present disclosure. Figure 5 The second semiconductor layer 106 is provided with a first step 201, and the bottom of the first step 201 is located in the second semiconductor layer 106; the dielectric layer 101 is located on the surface of the second semiconductor layer 106 where the first step 201 is not provided, and the reflective layer 102 covers the dielectric layer 101, the first surface of the epitaxial structure 10 and the first step 201.

[0114] In the embodiment of the present disclosure, the reflective layer may be an AuZn metal reflective layer. AuZn has high reflectivity and good corrosion resistance and can block water vapor corrosion while ensuring emissivity, thereby improving the yield of the light-emitting diode.

[0115] In other implementations, the reflective layer may also be an Ag metal reflective layer or an Au metal reflective layer. In other implementations, the reflective layer may be a stack of Ag and Au, or a stack of Ag and TiW.

[0116] S25, making transfer layers on the reflective layer and the substrate surface respectively, and bonding the two transfer layers into one layer.

[0117] Figure 6 Schematic diagram of a light emitting diode manufacturing process provided by the embodiment of the present disclosure. Figure 6 , the substrate 100 is connected to the reflective layer 102 through the transfer layer 107 .

[0118] In the embodiment of the present disclosure, the substrate may be a Si substrate.

[0119] In the embodiment of the present disclosure, the transfer layer is produced on the reflective layer and the substrate surface by electron beam evaporation equipment.

[0120] In the embodiment of the present disclosure, the transfer layer may be an Au transfer layer, or a transfer layer formed by a combination of Au and In, or a transfer layer formed by a combination of Ni and Sn.

[0121] For example, an Au transfer layer and an In transfer layer are respectively formed on the reflective layer and the substrate surface, or a Ni transfer layer and a Sn transfer layer are respectively formed on the reflective layer and the substrate surface, and then bonding is performed.

[0122] S26, performing a patterning process on the epitaxial structure so that the reflective layer extends out from a side surface of the epitaxial structure to form a second step.

[0123] In the embodiment of the present disclosure, the method of forming the second step 202 is the same as that of the first step 201 , and the main difference lies in the different surfaces that are subjected to the graphic processing.

[0124] Figure 7 Schematic diagram of a light emitting diode manufacturing process provided by the embodiment of the present disclosure. Figure 7 , the epitaxial structure 10 is patterned again to form a second step 202 , the bottom of which is located at the reflective layer 102 .

[0125] In the embodiment of the present disclosure, the width of the first step is equal to the width of the second step, which can ensure that the first step has a sufficient path to block the entry of water vapor and that the second step has a sufficient area to fit with the protective layer.

[0126] In other implementations, the width of the first step may also be smaller than or larger than the width of the second step.

[0127] S27, manufacturing a first electrode on the first semiconductor layer.

[0128] In one example, step S27 includes:

[0129] The first step is to prepare a first electrode metal layer.

[0130] In the embodiment of the present disclosure, the first electrode metal layer is manufactured using electron beam evaporation equipment.

[0131] In the embodiment of the present disclosure, the first electrode metal layer may be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0132] Exemplarily, the first electrode metal layer is a stack of Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0133] The second step is to perform patterning on the first electrode metal layer.

[0134] S28, making a protective layer on the epitaxial structure, wherein the protective layer covers the second surface of the epitaxial structure, the side surface of the epitaxial structure, and the second step.

[0135] In the disclosed embodiment, the protective layer may be a SiN protective layer. SiN has excellent chemical stability and weather resistance, and can effectively prevent corrosion of the substrate material by media such as water and oxygen, thereby improving the reliability and stability of the device. In addition, the SiN protective layer also has high hardness and good resistance to water vapor penetration, which can prevent water vapor corrosion and improve the yield of the light-emitting diode.

[0136] S29. Making a second electrode on a side of the substrate away from the transfer layer.

[0137] In the embodiment of the present disclosure, an electron beam evaporation device is used to manufacture the second electrode, and the second electrode is a full-surface electrode.

[0138] In the embodiment of the present disclosure, the second electrode may be a combination of one or more metal or alloy layers such as Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0139] Exemplarily, the second electrode is a stack of Cr, Al, AlCu, Ti, Ni, Pt and Au.

[0140] S30, cutting the round wafer.

[0141] In the embodiment of the present disclosure, a light-emitting diode wafer is obtained through steps S21 to S29, and the wafer is cut into small-sized light-emitting diode chips through laser cutting.

[0142] Table 1 below is a comparison of the test failure rate parameters of the light-emitting diode provided by the related art and the light-emitting diode provided by the embodiment of the present disclosure. Wherein, Ta is the temperature in °C. RH is the relative humidity. Based on Table 1, it can be seen that in the sealing glue high pressure cooking test (Pressure Cooker Test, PCT), under the conditions of temperature of 121±2°C, relative humidity of 100%, and pressure of 205KPa, the failure rate of the solution provided by the embodiment of the present disclosure is significantly reduced.

[0143] Table 1

[0144]

[0145] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A light emitting diode, characterized in that: The light emitting diode comprises: an epitaxial structure (10), a dielectric layer (101) and a reflective layer (102); The epitaxial structure (10) comprises a first surface and a second surface opposite to the first surface; The dielectric layer (101) is located on the first surface of the epitaxial structure (10), a first step (201) is provided at the edge of the first surface of the epitaxial structure (10), and the reflective layer (102) covers the dielectric layer (101), the first surface of the epitaxial structure (10), and the first step (201).

2. The light emitting diode according to claim 1, characterized in that: The epitaxial structure (10) comprises a first semiconductor layer (104), an active layer (105) and a second semiconductor layer (106) which are stacked in sequence, the second semiconductor layer (106) having a first surface close to the active layer (105) and a second surface away from the active layer (105); the second surface of the second semiconductor layer (106) is the first surface of the epitaxial structure (10), and the height (H) of the first step (201) is less than half the thickness of the second semiconductor layer (106).

3. The light emitting diode according to claim 1 or 2, characterized in that: The reflective layer (102) extends from a side surface of the epitaxial structure (10) to form a second step (202), and a width (W1) of the first step (201) is equal to a width (W2) of the second step (202).

4. The light emitting diode according to claim 3, characterized in that: The light emitting diode further comprises a protective layer (103), wherein the protective layer (103) covers the second surface of the epitaxial structure (10), the side surface of the epitaxial structure (10) and the second step (202).

5. The light emitting diode according to claim 4, characterized in that: The thickness of the protective layer (103) is less than or equal to the width (W2) of the second step (202).

6. The light emitting diode according to claim 5, characterized in that: The light emitting diode further comprises: a substrate (100), a transfer layer (107), a first electrode (108) and a second electrode (109); The reflective layer (102) is connected to one side of the substrate (100) through the transfer layer (107), the second surface of the epitaxial structure (10) is connected to the first electrode (108), and the other side of the substrate (100) is connected to the second electrode (109).

7. A method for preparing a light emitting diode, characterized in that: The method comprises: Manufacturing an epitaxial structure, the epitaxial structure comprising a first surface and a second surface opposite to the first surface; Fabricating a dielectric layer on the first surface of the epitaxial structure; A first step is provided at an edge of the first surface of the epitaxial structure; A reflective layer is manufactured, wherein the reflective layer covers the dielectric layer, the first surface of the epitaxial structure, and the first step.

8. The method for preparing a light emitting diode according to claim 7, characterized in that: The epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence. The second semiconductor layer is located on a first surface of the epitaxial structure. The height of the first step is less than half of the thickness of the second semiconductor layer.

9. The method for preparing a light emitting diode according to claim 7 or 8, characterized in that: The method further comprises: The epitaxial structure is patterned so that the reflective layer extends from a side surface of the epitaxial structure to form a second step, and the width of the first step is equal to the width of the second step.

10. The method for preparing a light emitting diode according to claim 9, characterized in that: The method further comprises: A protection layer is manufactured, wherein the protection layer covers the second surface of the epitaxial structure, the side surface of the epitaxial structure and the second step.

Images