Light emitting diode and method of manufacturing the same

Abstract

Disclosed are a light emitting diode and a method of manufacturing the same. The light emitting diode includes a second substrate, a bonding layer on the second substrate, a second semiconductor layer on the bonding layer, a quantum well layer on the second semiconductor layer, and a first semiconductor layer on the quantum well layer. The bonding layer of the light emitting diode of the present invention employs a doped oxide layer, and a doped element in the bonding layer absorbs moisture accumulated in the bonding layer during a high temperature process to prevent the epitaxial layer from peeling off.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a light emitting diode and a manufacturing method thereof. BACKGROUND

[0002] In the light emitting diode and the Mini / Micro light emitting diode, the sapphire substrate is usually used to replace the silicon substrate to realize the direct light emission from the transparent substrate. The specific process is to peel off the silicon substrate from the epitaxial layer, and then bond the epitaxial layer and the sapphire substrate through a bonding layer, which is usually an oxide or other polymer transparent adhesive material.

[0003] In order to improve the light emission efficiency of the epitaxial layer, the epitaxial layer is usually roughened to improve the surface roughness. However, with the increase of the roughness, the compactness of the bonding layer formed on the surface of the epitaxial layer will also decrease significantly, and the pores of the bonding layer will inevitably appear. This part of the pores is located at the bottom of the oxide layer and close to the roughened surface of the epitaxial layer, or presents a penetrating hole posture, and the depth can penetrate through the oxide layer and cannot be removed by polishing. In the subsequent cleaning and activation process, a large amount of gas and liquid will be adsorbed in this part of the pores or defects. The liquid and gas will expand sharply in the subsequent high temperature process, and will shrink sharply after cooling, causing the pores to bulge and collapse, and finally causing a large number of holes of the epitaxial layer to fall off.

[0004] Therefore, there is an urgent need for a light emitting diode and a manufacturing method thereof to absorb and remove the excess water and gas accumulated in the pores or defects of the bonding layer to prevent the epitaxial layer from falling off. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide a light emitting diode and a manufacturing method thereof, wherein the bonding layer of the light emitting diode adopts a doped oxide layer, and the doped element in the bonding layer absorbs the water accumulated in the bonding layer in the high temperature process to prevent the epitaxial layer from falling off.

[0006] According to a first aspect of the present application, a light emitting diode is provided, comprising:

[0007] a second substrate;

[0008] a bonding layer located on the second substrate;

[0009] a second semiconductor layer located on the bonding layer;

[0010] a quantum well layer located on the second semiconductor layer; and

[0011] a first semiconductor layer located on the quantum well layer.

[0012] Preferably, the bonding layer is one or several of a SiO2 layer, an Al2O3 layer, a SiN layer, and a MgF2 layer. x Preferably, the doping element of the bonding layer is at least one of silicon, copper, calcium, and barium.

[0013] Preferably, the doping element of the bonding layer is at least one of silicon, copper, calcium, and barium.

[0014] Preferably, the mass ratio of the doping element in the bonding layer is 1% to 5%.

[0015] Preferably, the thickness of the bonding layer is 1 μm to 4 μm.

[0016] Preferably, the bonding layer is free of water and gas.

[0017] Preferably, the method further comprises:

[0018] a first electrode on the first semiconductor layer and electrically connected to the first semiconductor layer; and

[0019] a second electrode on a surface of the second substrate distal to the bonding layer and electrically connected to the second substrate.

[0020] Preferably, the bonding layer comprises a first bonding layer and a second bonding layer.

[0021] Preferably, the light emitting diode is a Micro Light Emitting Diode or a Mini Light Emitting Diode.

[0022] According to a second aspect of the present application, there is provided a method of manufacturing a light emitting diode, comprising:

[0023] forming a first semiconductor layer, a quantum well layer, and a second semiconductor layer on a first substrate in sequence;

[0024] forming a bonding layer on at least the second semiconductor layer;

[0025] bonding the second semiconductor layer to a second substrate via the bonding layer;

[0026] peeling the first substrate from the first semiconductor layer.

[0027] Preferably, the bonding layer is one or several of a SiO2 layer, an Al2O3 layer, a SiN layer, and a MgF2 layer. x Preferably, the doping element of the bonding layer is at least one of silicon, copper, calcium, and barium.

[0028] Preferably, the doping element of the bonding layer is at least one of silicon, copper, calcium, and barium.

[0029] Preferably, the thickness of the bonding layer is 1 μm to 4 μm.

[0030] Preferably, the bonding layer is free of water and gas.

[0031] Preferably, the bonding layer is formed by one of electron beam evaporation deposition, metal organic chemical vapor deposition or plasma enhanced chemical vapor deposition.

[0032] Preferably, the mass ratio of the doping element in the reaction target for forming the bonding layer is 1% to 5%.

[0033] Preferably, the reaction target for forming the bonding layer is a ceramic target.

[0034] Preferably, the method further comprises a pre-bonding treatment of the bonding layer before bonding the bonding layer with the second substrate.

[0035] Preferably, the method of pre-bonding treatment of the bonding layer comprises at least one of vacuum heating of the bonding layer and ultraviolet irradiation of the bonding layer.

[0036] Preferably, the vacuum heating of the bonding layer is performed in an environment with a vacuum degree of 1 x 10 -5 ~1 x 10 -6 torr.

[0037] Preferably, the temperature of the vacuum heating of the bonding layer is 110°C to 150°C.

[0038] Preferably, the ultraviolet irradiation of the bonding layer is performed for 1 minute to 10 minutes.

[0039] Preferably, the method further comprises, before the pre-bonding treatment of the bonding layer:

[0040] polishing the surface of the bonding layer; and

[0041] cleaning the surface of the bonding layer with ammonia water or organic solution;

[0042] wherein, after the polishing of the surface of the bonding layer, the roughness of the surface of the bonding layer is less than 1 nm.

[0043] Preferably, the surface of the second semiconductor layer in contact with the bonding layer is a rough surface.

[0044] Preferably, the method further comprises:

[0045] forming a first electrode on the first semiconductor layer; and

[0046] forming a second electrode on the second substrate.

[0047] Preferably, the method of forming the bonding layer comprises:

[0048] forming a first bonding layer on a second semiconductor layer; and

[0049] forming a second bonding layer on the second substrate;

[0050] The second semiconductor layer is bonded together with the second substrate through the first bonding layer and the second bonding layer.

[0051] Preferably, the light emitting diode is a Micro Light Emitting Diode or a Mini Light Emitting Diode.

[0052] In the embodiments of the present application, the bonding layer adopts a doped oxide layer, wherein the doped element of the oxide layer reacts with water adsorbed in the pores or defects of the bonding layer, eliminating the water adsorbed in the pores or defects of the bonding layer, preventing the water in the pores or defects of the bonding layer from expanding violently under the action of high temperature and shrinking sharply after cooling, causing the pores to swell and collapse, further preventing the exfoliation of the epitaxial layer, so that the light emitting diode can maintain the integrity of the epitaxial layer morphology, which is beneficial to the yield and output of the light emitting diode.

[0053] In some embodiments, the bonding layer is formed by an electron beam evaporation deposition process to meet the thickness requirement of the bonding layer, reduce the cost, and further prevent the accumulation of hydrogen under the bonding layer and the further exfoliation of the epitaxial layer.

[0054] In some embodiments, the mass ratio of the doped element of the bonding layer is 1% to 5% to prevent insufficient reaction with water due to too low doping amount, and to prevent changes in the lattice of the bonding layer due to too high doping amount, further preventing a large number of dislocations and defects in the bonding layer.

[0055] In some embodiments, the bonding layer is subjected to a pre-bonding treatment to remove water, gas, and hydrocarbons that may exist at the bonding interface, and the surface of the bonding layer is polished and cleaned to improve the bonding strength of the bonding layer, reduce the bonding failure area, and further improve the overall bonding yield and bonding strength. BRIEF DESCRIPTION OF DRAWINGS

[0056] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings, in which:

[0057] Figure 1 shows a cross-sectional schematic diagram of a light emitting diode of the prior art;

[0058] Figure 2 shows a cross-sectional schematic diagram of a light emitting diode of the present application;

[0059] Figures 3a to 3c shows the structure cross-sectional diagram of a light emitting diode of the present application at different stages of the manufacturing process. DETAILED DESCRIPTION

[0060] The present application will be described in more detail with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. Each part of the figures is not drawn to scale for the sake of clarity. Further, certain known elements can not be shown.

[0061] The present application can take various forms, some examples of which will be described below.

[0062] Figure 1 A schematic diagram showing a bonding process in the prior art is shown in FIG. 1. In the prior art, the light emitting diode comprises, from bottom to top, a second electrode 260, a second substrate 240, a bonding layer 230, an epitaxial layer 220, and a first electrode 250. The epitaxial layer 220 comprises, from bottom to top, a second semiconductor layer 223, a quantum well layer 222, and a first semiconductor layer 221. The first electrode 250 is electrically connected to the first semiconductor layer 221, and the second electrode 260 is electrically connected to the second substrate 240.

[0063] The bonding of the epitaxial layer 220 and the second substrate 240 is achieved through the bonding layer 230. Due to the process of forming the bonding layer 230 and the surface topography of the second semiconductor layer 223, there will be holes or defects in the bonding layer 230 (as shown in S of FIG. 2). During the cleaning of the surface of the bonding layer 230, a large number of water molecules are adsorbed on the surface of the bonding layer 230. During the bonding process, the excessive hydrogen bonds (more than four hydrogen bonds) will break, and the excessive water molecules will also cause a large amount of water molecules to accumulate in the bonding layer 230. These water molecules accumulate in the holes or defects in the bonding layer 230. The water molecules accumulated in the holes and defects of the bonding layer 230 will expand dramatically during the subsequent high temperature process, and will shrink sharply after cooling, further causing the epitaxial layer 220 to bubble or break (as shown in S1 of FIG. 2), and finally causing the epitaxial layer 220 to fall off. Figure 1 Figure 1

[0064] Figure 2 A cross-sectional schematic diagram of a light emitting diode according to an embodiment of the present application is shown. It should be noted that the embodiment of the present application is described by taking a light emitting diode with a vertical structure as an example, but it is not difficult to understand that the embodiment of the present application is applicable to any light emitting diode that needs oxide bonding.

[0065] As shown in FIG. 3, the light emitting diode according to the embodiment of the present application comprises, from bottom to top, a second electrode 260, a second substrate 240, a bonding layer 230, an epitaxial layer 220, and a first electrode 250. The epitaxial layer 220 comprises, from bottom to top, a second semiconductor layer 223, a quantum well layer 222, and a first semiconductor layer 221. The first electrode 250 is electrically connected to the first semiconductor layer 221, and the second electrode 260 is electrically connected to the second substrate 240. Figure 2 ​​As shown, the light emitting diode is a Micro Light Emitting Diode or a Mini Light Emitting Diode, which comprises a second electrode 160, a second substrate 140, a bonding layer 130, an epitaxial layer 120 and a first electrode 150 from bottom to top, the epitaxial layer 120 comprises a second semiconductor layer 123, a quantum well layer 122 and a first semiconductor layer 121 from bottom to top, the first electrode 150 is electrically connected with the first semiconductor layer 121, and the second electrode 160 is electrically connected with the second substrate 140.

[0066] The surface of the second semiconductor layer 123 away from the first semiconductor layer 121 has a rough morphology, which is more conducive to light emitting diode light emission and improves the light emitting efficiency of the epitaxial layer 120. The bonding layer 130 is located on the surface of the second semiconductor layer 123 with rough morphology, that is, the bonding layer 130 and the second semiconductor layer 123 are in contact with the rough surface. The second substrate 140 and the epitaxial layer 120 (the second semiconductor layer 123) are bonded together through the bonding layer 130.

[0067] The second substrate 140 is a sapphire substrate, a silicon oxide substrate, a zinc oxide substrate with a surface evaporation SiO2 layer, etc., and the material of the epitaxial layer 120 is a III-V semiconductor material.

[0068] In one specific embodiment, the second substrate 140 is, for example, a sapphire substrate, the material of the first semiconductor layer 121 is, for example, gallium arsenide (GaAs), the quantum well layer 122 is configured as a multi-period quantum well layer, and the material of the second semiconductor layer 123 is, for example, gallium phosphide (GaP), but is not limited thereto.

[0069] The bonding layer 130 is, for example, a calcium-doped silicon oxide layer. In a preferred embodiment, the bonding layer 130 is, for example, a combination of one or more of a SiO2 layer, an Al2O3 layer, a SiN x layer, a MgF2 layer, and the doping element is at least one of Si, Cu, Ca and Ba.

[0070] In this embodiment, the elemental or oxide dopant in the bonding layer 130 has the chemical property of reacting with and consuming water. The dopant element (e.g., at least one of Si, Cu, Ca, and Ba) reacts with the water adsorbed in the pores or defects of the bonding layer 130 in the form of an elemental or oxide during the bonding process of the second substrate 140 and the epitaxial layer 120 through the bonding layer 130. This eliminates the water adsorbed in the pores or defects of the bonding layer 130, thereby compensating for the impact of the bonding layer 130 quality caused by the process of forming the bonding layer 130 and the rough morphology of the epitaxial layer 120. This allows the light-emitting diode, Micro light-emitting diode, or Mini light-emitting diode to maintain the integrity of the epitaxial layer morphology, which is beneficial to improving the bonding strength and the yield and output of the light-emitting diode.

[0071] Among them, the doping elements Cu, Ca, and Ba are more reactive and generally react with water in the form of oxides, while the doping element Si generally reacts with water in the form of an element.

[0072] Figures 3a to 3c The accompanying drawings show cross-sectional views of the light-emitting diode (LED) at different stages of its manufacturing process according to an embodiment of the present invention. The manufacturing method provided in this embodiment operates on the entire wafer; for ease of understanding, only one LED unit is shown in the drawings.

[0073] like Figure 3a As shown, an epitaxial layer 120 is formed on the surface of the first substrate 110.

[0074] In this step, for example, a metal-organic chemical vapor deposition process is used to form an epitaxial layer 120 on the surface of the first substrate 110, wherein the epitaxial layer 120 includes a first semiconductor layer 121, a quantum well layer 122 and a second semiconductor layer 123 from bottom to top.

[0075] The surface of the second semiconductor layer 123 has a rough morphology (e.g., Figure 3a The serrated surface of the epitaxial layer 123 (compared to a smooth surface) is more conducive to light emission from the LED, thus improving the light emission efficiency of the epitaxial layer 120. For example, the surface of the second semiconductor layer 123 can be roughened by dry etching or wet etching to form a rough surface on the surface of the second semiconductor layer 123.

[0076] The first substrate 110 is, for example, a gallium arsenide (GaAs) substrate, a silicon carbide (SiC) substrate, a gallium nitride (GaN) substrate, a sapphire substrate, etc. In one specific embodiment, the first substrate 110 is, for example, a gallium arsenide (GaAs) substrate, the material of the first semiconductor layer 121 is, for example, gallium arsenide (GaAs), the quantum well layer 122 is configured as a multi-period quantum well layer, and the material of the second semiconductor layer 123 is, for example, gallium phosphide (GaP), but is not limited thereto.

[0077] As shown in Figure 3b The surface of the second semiconductor layer 123 forms a bonding layer 130. The bonding layer 130 can be formed by an electron beam evaporation deposition process, a MOVCD (metal organic chemical vapor deposition) process, a PECVD (plasma enhanced chemical vapor deposition) process, etc.

[0078] In this embodiment, the bonding layer 130 is formed by an electron beam evaporation deposition process. An ALD atomic layer deposition process can obtain a pore-free and defect-free oxide layer, but the ALD atomic layer deposition process is suitable for forming an oxide layer with a thickness of 100 nm or less. In this embodiment, the thickness of the bonding layer 130 is required to be greater than 1 μm, and the ALD atomic layer deposition process cannot meet the thickness requirement of the bonding layer 130. Moreover, the ALD atomic layer deposition process is expensive and is not suitable for widespread industrial production. On the other hand, the ALD atomic layer deposition process is a chemical reaction method, so after the oxide layer is formed by the ALD atomic layer deposition process, hydrogen will accumulate under the oxide layer. In the subsequent high-temperature bonding process of the oxide layer, the hydrogen accumulated under the oxide layer will be converted into H2 and H2O, causing a dramatic volume expansion change, which leads to the rupture of the epitaxial layer.

[0079] In this embodiment, the bonding layer 130 is formed by an electron beam evaporation deposition process to meet the thickness requirement of the bonding layer, reduce costs, and prevent the accumulation of hydrogen under the bonding layer and further prevent the rupture of the epitaxial layer.

[0080] The deposition rate of the electron beam evaporation deposition process is fast, and due to the influence of the rough morphology of the surface of the second semiconductor layer 123, there will be pores or defects in the bonding layer 130 formed, as shown in Figure 3bAs shown at point S in the diagram. During subsequent polishing of the bonding layer 130 surface, some pores or defects formed on the surface of the bonding layer 130 can be eliminated, but pores or defects deeply embedded within the bonding layer 130, as well as those penetrating the entire thickness direction of the bonding layer 130, cannot be eliminated. During subsequent cleaning of the bonding layer 130 surface, a large number of water molecules are adsorbed into the pores and defects of the bonding layer 130. During subsequent high-temperature treatment (e.g., high-temperature annealing), the water molecules expand violently and contract rapidly after cooling, causing bulging and collapse at the pores or defects, ultimately leading to the detachment of the epitaxial layer 120.

[0081] To eliminate the impact of pores or defects inside or on the surface of the bonding layer 130, in this embodiment, the bonding layer 130 is a doped oxide layer, wherein the elemental or oxide dopant of the oxide layer has the chemical property of reacting with and consuming water. The elemental or oxide dopant reacts with the water adsorbed in the pores or defects of the bonding layer 130, eliminating the water adsorbed in the pores or defects of the bonding layer 130, thereby compensating for the impact of the process for forming the bonding layer 130 and the rough morphology of the epitaxial layer 120 on the quality of the bonding layer 130.

[0082] In a preferred embodiment, the bonding layer 130 is, for example, a SiO2 layer, an Al2O3 layer, or a SiN layer. x One or more of the MgF2 layer and the doping element is at least one of Si, Cu, Ca and Ba.

[0083] In one specific embodiment, the bonding layer 130 is a calcium-doped silicon oxide layer, and the bonding layer 130 is formed using a ceramic target, which is formed, for example, from silicon oxide powder and calcium oxide powder. The mass ratio of calcium in the silicon oxide powder and calcium oxide powder after doping is 1% to 5%. Too low a calcium content will lead to insufficient subsequent water bonding; too high a calcium content will cause changes in the lattice of the bonding layer 130, further resulting in a large number of dislocations and defects in the formed bonding layer 130.

[0084] In one specific embodiment, the purity of the silicon oxide powder is, for example, 99.99%, and the particle size is, for example, 100 nm to 1 μm. The particle size of the calcium oxide powder is 50 nm. The silicon oxide powder and calcium oxide powder are mixed and ground uniformly. The doped silicon oxide powder and calcium oxide powder are pressed into a cylindrical block with a diameter of 25 mm under a uniaxial pressure of 20 MPa, for example. Finally, the block is sintered at 1100°C for 6 hours, for example, to form a ceramic target.

[0085] Then, the cleaned ceramic target and the semiconductor wafer are installed into a reaction chamber of an evaporation device, and an oxidizing gas (e.g., oxygen) is introduced into the reaction chamber under vacuum and high temperature, and then evaporation deposition is performed on the surface of the second semiconductor layer to improve the density of the bonding layer.

[0086] In one embodiment, the reaction chamber of the evaporation device is evacuated to 6 x 10 -6 torr, the semiconductor wafer is heated to 300°C, the rotation speed of the semiconductor wafer is maintained at 6 rpm to 10 rpm (e.g., 8 rpm), and the semiconductor wafer is preheated for 30 minutes before oxygen is introduced at a flow rate of 0 sccm to 10 sccm (e.g., 6 sccm). During the evaporation, the voltage of the electron beam is, for example, 5 kV to 10 kV (e.g., 8 kV), the electron beam current is, for example, 0.05 mA to 0.15 mA (e.g., 0.1 mA), and the evaporation rate is, for example, 0.5 Å / s to 3 Å / s (e.g., 2 Å / s).

[0087] Further, the semiconductor wafer including the bonding layer is subjected to vacuum annealing, and the annealing time is, for example, 0 to 40 minutes. In one embodiment, the annealing time is, for example, 10 minutes.

[0088] The bonding layer 130 having a thickness of 1 μm to 4 μm is formed through the above steps. In one embodiment, the thickness of the bonding layer 130 is, for example, 2 μm.

[0089] In this embodiment, the bonding layer 130 is a calcium-doped silicon oxide layer, and the reaction target is a ceramic target. It is understood that when the material of the bonding layer 130 is changed, the reaction target is correspondingly changed, and the material ratio of the reaction target, the evaporation process conditions of the bonding layer 130, etc. are also correspondingly changed. Those skilled in the art can make corresponding changes according to specific needs, as long as the mass ratio of the doping element in the reaction target is 1% to 5%. This embodiment is not limited in this regard.

[0090] Further, the surface of the bonding layer 130 away from the epitaxial layer 120 is polished, and the surface of the bonding layer 130 away from the epitaxial layer 120 and the first surface of the second substrate 140 are bonded together in a subsequent bonding process. By polishing the surface of the bonding layer 130 away from the epitaxial layer 120, part of the pores and defects on the surface of the bonding layer 130 away from the second substrate 200 can be removed. After polishing, the roughness of the surface of the bonding layer 130 away from the epitaxial layer 120 is less than 1 nm, and the bonding layer 130 has a relatively smooth bonding surface, thereby improving the bonding strength.

[0091] Further, the surface of the bonding layer 130 away from the epitaxial layer 120 and the second substrate 140 are cleaned to remove the polishing solution particles and the bonding layer material particles remained on the surface of the bonding layer 130, and the particles and organic impurities in the air adsorbed on the second substrate 140, so as to obtain the bonding layer 130 and the second substrate 140 with clean surface and no organic matter attached, and improve the hydrophilicity of the surface of the bonding layer 130 away from the epitaxial layer 120. In an embodiment, the surface of the bonding layer 130 and the first surface of the second substrate 140 are cleaned by using ammonia solution. Further, the cleaning is performed by using organic solvent.

[0092] In the bonding process, the water molecules act as a bridge. When the water molecules adsorbed on the surface of the bonding layer 130 away from the epitaxial layer 120 are insufficient, the bonding cannot be performed, and the bonding fails. In this embodiment, the surface of the bonding layer 130 away from the epitaxial layer 120 is cleaned, and a large amount of water is adsorbed on the surface of the bonding layer 130 away from the epitaxial layer 120, so as to ensure the sufficiency of water on the surface of the bonding layer 130 away from the epitaxial layer 120.

[0093] Further, the surface of the bonding layer 130 is treated before bonding, and the treatment of the surface of the bonding layer 130 before bonding includes vacuum heating of the bonding layer 130 and / or ultraviolet irradiation of the bonding layer.

[0094] Specifically, the semiconductor structure including the bonding layer 130 is placed in a vacuum environment, and the vacuum degree is 1x10 -5 ~1x10 -6 torr, for example, 6x10 -5 torr. The temperature is increased from room temperature to 110-150°C (for example, 130°C) within 3 minutes. By vacuum heating of the semiconductor wafer including the bonding layer 130, the water vapor in the bonding layer 130 and the water vapor on the surface of the bonding layer 130 are removed.

[0095] Further, the bonding layer 130 is irradiated by ultraviolet light to remove the hydrocarbons possibly existing on the surface of the bonding layer 130. In an embodiment, the bonding layer 130 is irradiated by ultraviolet light with a power of 20 W for 1-10 minutes, for example, 2 minutes.

[0096] In this embodiment, by treating the surface of the bonding layer before bonding, the water, gas and hydrocarbons possibly existing on the bonding interface are removed, the cleanliness of the bonding interface is greatly improved, the surface of the bonding layer is polished and cleaned to improve the bonding strength of the bonding layer, the bonding failure area is reduced, and the overall bonding yield and bonding strength are improved.

[0097] As Figure 3c shown, the semiconductor wafer is bonded to the second substrate 140 through the bonding layer 130. In this embodiment, the second substrate 140 is, for example, a sapphire substrate.

[0098] The method of bonding the semiconductor wafer including the bonding layer 130 to the second substrate 140 includes a pre-bonding process and a secondary bonding process.

[0099] In the pre-bonding process, the water molecules adsorbed on the surface of the bonding layer 130 and the water molecules adsorbed on the surface of the second substrate 140 are linked together through hydrogen bonds, thereby realizing the pre-bonding between the bonding layer 130 and the second substrate 140.

[0100] Further, the pre-bonding process is performed in a vacuum environment.

[0101] The bonding layer 130 and the second substrate 140 after the pre-bonding are subjected to the secondary bonding within a first time interval, and the secondary bonding is completed in a bonder. In this embodiment, the first time interval is less than or equal to 3 minutes.

[0102] In this embodiment, the second substrate 140 is directly bonded to the bonding layer 130, and in other embodiments, the same bonding layer 130 can be formed on the surface of the second substrate 140 and the second semiconductor layer 123 by the above method, and the bonding process between the second substrate 140 and the second semiconductor layer 123 is actually the bonding between the first bonding layer on the surface of the second semiconductor layer 123 and the second bonding layer on the surface of the second substrate 140.

[0103] Further, the first substrate 110 is peeled off, and a first electrode 150 is formed on the first semiconductor layer 121, and a second electrode 160 is formed on the second substrate 140, as Figure 1 shown.

[0104] In this step, the first electrode 150 and the second electrode 160 are formed, for example, by evaporation, and after the evaporation is completed, annealing is performed at a temperature of 300°C to 600°C.

[0105] In this embodiment, the element or oxide of the bonding layer 130 has a chemical property of reacting with water and consuming water. For example, in a specific embodiment, the element of the bonding layer 130 is calcium, which is oxidized to form an oxide in the process of forming the bonding layer, and the oxide reacts with water in the bonding process. The chemical equation of the oxidation of calcium to form the oxide and the reaction of the oxide with water is:

[0106] 2Ca + O2 = 2CaO

[0107] CaO + H2O = Ca(OH)2

[0108] In yet another specific embodiment, the doping element in the bonding layer 130 is barium element, and the doping element in the bonding layer 130 is oxidized to form an oxide, and the chemical equation of the reaction between the oxide and water is:

[0109] 2Ba + O2 = 2BaO

[0110] BaO + H2O = Ba(OH)2

[0111] In yet another specific embodiment, the doping element in the bonding layer 130 is silicon element, and the silicon element remains as an element during the formation of the bonding layer, and the elemental silicon reacts with water during the bonding process, and the chemical equation is:

[0112] Si + 4H2O = H4SiO4 + 2H2↑

[0113] The hydrogen molecule formed has a small molecular weight, and does not cause a sharp change in volume when expanded at high temperature, thereby preventing the epitaxial layer from being broken.

[0114] In the embodiment, the element or the oxide formed by the oxidation of the doping element in the bonding layer 130 reacts with water present in the bonding layer 130 at high temperature, preventing the water in the holes or defects in the bonding layer 130 from being vaporized and sharply expanded under the action of high temperature, and from being sharply contracted after cooling, causing the holes to swell and collapse, further preventing the epitaxial layer from being detached, so that the light emitting diode can maintain the integrity of the epitaxial layer morphology, which is beneficial to the yield and output of the light emitting diode.

[0115] In the embodiment, the bonding layer adopts a doped oxide layer, and the element or the oxide of the doping element of the oxide layer reacts with the water adsorbed in the holes or defects of the bonding layer, eliminating the water adsorbed in the holes or defects of the bonding layer, preventing the water in the holes or defects in the bonding layer from being sharply expanded under the action of high temperature, and from being sharply contracted after cooling, causing the holes to swell and collapse, further preventing the epitaxial layer from being detached, so that the light emitting diode can maintain the integrity of the epitaxial layer morphology, which is beneficial to the yield and output of the light emitting diode.

[0116] In some embodiments, the bonding layer is formed by an electron beam evaporation deposition process to meet the thickness requirement of the bonding layer, reduce the cost, and prevent the aggregation of hydrogen under the bonding layer, further preventing the epitaxial layer from being broken.

[0117] In some embodiments, the mass ratio of the doping element of the bonding layer is 1% to 5%, so as to prevent too low doping amount from causing insufficient reaction with water later, while preventing too high doping amount from causing change of the lattice of the bonding layer, further preventing the bonding layer from generating a large number of dislocations and defects.

[0118] In some embodiments, the bonding layer is subjected to a pre-bonding treatment to remove water, gas, hydrocarbon that may exist at the bonding interface, and the surface of the bonding layer is polished and cleaned to improve the bonding strength of the bonding layer, reduce the bonding failure area, and further improve the overall bonding yield and bonding strength.

[0119] The embodiments in accordance with the present application as described above are not exhaustive in describing all details, nor limit the present application to only the specific embodiments described. It is apparent that many modifications and variations can be made in light of the above description. The present description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses based on the present application. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. A light emitting diode, characterized by, The application relates to a light emitting diode, comprising: a second substrate; a bonding layer on the second substrate; a second semiconductor layer on the bonding layer; a quantum well layer on the second semiconductor layer; and a first semiconductor layer on the quantum well layer; a mass ratio of a doping element in the bonding layer is 1%-5%. The bonding layer is one or more of SiO2 layer, Al2O3 layer, SiN x layer, MgF2 layer, and the doping element of the bonding layer is at least one of silicon, copper, calcium, and barium; the doping element or oxide thereof has a chemical property of reacting with water and consuming water.

2. The light emitting diode of claim 1, wherein, The thickness of the bonding layer is 1-4 mu m.

3. The light emitting diode of claim 1, wherein, The bonding layer is free of water and gas.

4. The light emitting diode of claim 1, wherein, The application further comprises:

5. The light emitting diode of claim 1, wherein, a first electrode on the first semiconductor layer and electrically connected to the first semiconductor layer; and a second electrode on a surface of the second substrate away from the bonding layer and electrically connected to the second substrate. The bonding layer comprises a first bonding layer and a second bonding layer. The light emitting diode is a micro light emitting diode or a mini light emitting diode.

6. The light emitting diode of claim 1, wherein, The application relates to a method for manufacturing a light emitting diode, comprising:

7. The light emitting diode of claim 1, wherein, forming a first semiconductor layer, a quantum well layer and a second semiconductor layer on a first substrate in sequence; 8. A method of manufacturing a light emitting diode, characterized by: forming a bonding layer on at least the second semiconductor layer; bonding the second semiconductor layer to a second substrate through the bonding layer; peeling the first substrate from the first semiconductor layer; The thickness of the bonding layer is 1-4 mu m. The bonding layer is free of water and gas. The bonding layer is one or more of SiO2 layer, Al2O3 layer, SiN x layer, MgF2 layer; the doping element of the bonding layer is at least one of silicon, copper, calcium, barium; the doping element or oxide thereof of the bonding layer has a chemical property of reacting with water and consuming water.

9. The method of manufacturing a light emitting diode according to claim 8, wherein The bonding layer is formed by one of electron beam evaporation deposition, metal organic chemical vapor deposition and plasma enhanced chemical vapor deposition.

10. The method of manufacturing a light emitting diode according to claim 8, wherein A mass ratio of a doping element in a reaction target for forming the bonding layer is 1%-5%.

11. The method of manufacturing a light emitting diode according to claim 8, wherein The reaction target for forming the bonding layer is a ceramic target.

12. The method of claim 8, wherein the method further comprises: The method further comprises a pre-bonding treatment of the bonding layer before the bonding of the bonding layer to the second substrate.

13. The method of manufacturing a light emitting diode according to claim 12, wherein The pre-bonding treatment of the bonding layer comprises at least one of vacuum heating of the bonding layer and ultraviolet irradiation of the bonding layer.

14. The method of claim 8, wherein the method further comprises: The temperature of the vacuum heating of the bonding layer is 110-150 DEG C.

15. The method of manufacturing a light emitting diode according to claim 14, wherein The ultraviolet irradiation of the bonding layer lasts for 1-10 minutes.

16. The method of manufacturing a light emitting diode according to claim 15, wherein The process of vacuum heating the bonding layer is performed in an environment having a vacuum degree of 1 x 10 -5 -1 x 10 -6 torr.

17. The method of claim 15, wherein the method further comprises: The method further comprises:

18. The method of claim 15, wherein the method further comprises: polishing a surface of the bonding layer; and 19. The method of claim 14, wherein cleaning the surface of the bonding layer by using ammonia water or an organic solution. The roughness of the surface of the bonding layer is less than 1 nm after the polishing of the surface of the bonding layer. The surface of the second semiconductor layer in contact with the bonding layer is a rough surface. The method further comprises:

20. The method of claim 8, wherein the method further comprises: forming a first electrode on the first semiconductor layer; and 21. The method of claim 8, wherein the method further comprises: forming a second electrode on the second substrate. The method for forming the bonding layer comprises: forming a first bonding layer on the second semiconductor layer; and forming a second bonding layer on the second substrate; 22. The method of claim 8, wherein the method further comprises: The second semiconductor layer is bonded to the second substrate through the first bonding layer and the second bonding layer. The light emitting diode is a micro light emitting diode or a mini light emitting diode. ​ ​ 23. The method of claim 8, wherein the method further comprises: ​

Images