CN113782655A

CN113782655A - A kind of light-emitting diode and preparation method thereof

Info

Publication number: CN113782655A
Application number: CN202110893890.3A
Authority: CN
Inventors: 黄敏; 刘小亮; 彭康伟; 林素慧
Original assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Current assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2021-12-10
Also published as: CN110491980A; CN110491980B

Abstract

The present invention provides a light-emitting diode and a method for preparing the same. The light-emitting diode includes a light-emitting epitaxial layer, and the light-emitting epitaxial layer includes a first mesa and a second mesa and is formed on the surfaces and side surfaces of the first mesa and the second mesa The insulating protective layer includes an Al-containing insulating layer, and can form a single-layer or multi-layer stack structure. The use of an insulating protective layer containing Al can reduce the replacement of Al ions in the epitaxial layer, and at the same time can effectively compensate for the missing Al ions in the epitaxial layer in the chip manufacturing process, and will not affect the Si doping in the epitaxial layer, so that the epitaxial layer will not be damaged. , to avoid the aging failure of the epitaxial layer. The Al-containing insulating protective layer has a low absorption rate in the ultraviolet band, and at the same time, when the Al-containing insulating layer with a multilayer structure is formed, a layered structure of insulating films with high and low refractive indices can be formed, thereby achieving the purpose of brightening.

Description

Light emitting diode and preparation method thereof

The application is a divisional application of an invention patent with the application number of 2019107041772 and the invention name of 'an ultraviolet LED chip and a preparation method thereof' filed by 'Xiamensan Ann photoelectric Co Ltd' on 2019.

Technical Field

The invention relates to the technical field of semiconductor lighting, in particular to a light-emitting diode and a preparation method thereof.

Background

A Light Emitting Diode (LED) is a semiconductor device that emits light by releasing energy when carriers are combined. The huge application value of ultraviolet light LEDs (uv LEDs), especially deep ultraviolet light LEDs, has attracted people's high attention and become a new research hotspot.

The insulating protective layer of the UV LED product on the market at present usually adopts SiO₂. In the process of depositing the insulating protective layer, the insulating protective layer covers not only the P-AlGaN and the metal contact layer thereof, but also the cutting channel and the quantum hydrazine. Thus, in depositing SiO₂In the process (no matter PECVD or ALD is used), the deposition temperature needs to reach over 240 ℃ so as to achieve the purpose of high density, and because the content proportion of Si in the deposition process is far lower than that of Si in quantum hydrazine (if the content proportion of Si in the deposition process is consistent with that of Si in the quantum hydrazine, SiO is added₂The Si content of the film layer becomes larger, the absorption rate of the film layer becomes higher, and brightness loss is caused), so the Si in the quantum hydrazine is replaced out to enter the SiO by the diffusion principle₂The Si content in the quantum hydrazine of the film layer is changed, so that EPI (light-emitting epitaxial layer) is damaged in the deposition process, and the EPI is easy to lose efficacy in the aging process. This theory has been verified on blue GaN and FC. In other publications it is proposed to use SiO₂Are laminated, i.e. high and low refractive index, to achieve the brightening effect, but SiO₂When the Si content is more, the refractive index of the film becomes larger, and the film is stacked with other high-refractive-index film layers, so that the brightening effect is greatly reduced. And SiO₂The thermal conductivity is only 1.4W/m.k, the thicker the film thickness,the poorer the heat dissipation, the more it will fail due to thermal effects during aging. In addition, SiO₂The material is hydrophilic, the water vapor entering time is only delayed by adjusting the recipe proportion or increasing the thickness of the material, the water vapor entering cannot be avoided essentially, and the high-humidity aging resistance of the material is weak due to the characteristic.

Disclosure of Invention

Aiming at the defects of an insulating protection layer of an ultraviolet LED chip in the prior art, the invention provides the ultraviolet LED chip and the preparation method thereof. Meanwhile, the insulating layer containing Al is adopted, Al ions missing from the luminous epitaxial layer in the chip preparation process can be compensated, and the purpose of protecting the luminous epitaxial layer is achieved.

According to a first aspect of the present invention, there is provided an ultraviolet LED chip comprising:

the light-emitting epitaxial layer comprises a first table top and a second table top, the first table top comprises a first semiconductor layer, the second table top comprises an active layer formed on the first semiconductor layer and a second semiconductor layer formed above the active layer and having the opposite conductivity type to that of the first semiconductor layer; and

and the insulating protective layer is formed above the light-emitting epitaxial layer, formed on the surfaces and the side surfaces of the first table board and the second table board and comprises an insulating layer containing Al.

Optionally, the insulating protection layer comprises at least one insulating layer, wherein the underlying insulating layer in direct contact with the light emitting epitaxial layer comprises an Al-containing insulating layer. Optionally, the insulating protection layer includes at least one insulating layer, and the at least one insulating layer includes an Al-containing insulating layer.

Optionally, the insulating protective layer is made of Al₂O₃AlN, AlON and AlF₃At least one of (a).

Optionally, the insulating protection layer has an electrode through hole, the ultraviolet LED chip further includes a first electrode and a second electrode formed through the electrode through hole, the first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the second semiconductor layer.

Optionally, the first electrode includes a first metal contact layer formed over the first semiconductor layer and a first electrode layer formed in the electrode via and covering the electrode via and connected to the first metal contact layer; the second electrode comprises a metal reflecting layer formed above the second semiconductor layer and a second electrode layer formed in the electrode through hole and covering the electrode through hole and the metal reflecting layer.

Optionally, the insulating protection layer includes a stacked structure formed by alternately forming a first insulating layer and a second insulating layer, wherein a refractive index of the first insulating layer is smaller than a refractive index of the second insulating layer, and the stacked structure of the insulating protection layer forms a reflective structure of the ultraviolet LED chip.

Optionally, the first insulating layer comprises AlF₃And the second insulating layer comprises AlN.

According to a second aspect of the present invention, the present invention provides a method for preparing an ultraviolet LED chip, comprising the steps of:

forming a light-emitting epitaxial layer, and sequentially depositing a first semiconductor layer, an active layer and a second semiconductor layer with the conductivity type opposite to that of the first semiconductor layer, wherein the first semiconductor layer forms a first table top of the light-emitting epitaxial layer, and the active layer and the second semiconductor layer form a second table top of the light-emitting epitaxial layer;

and forming an insulating protection layer above the light-emitting epitaxial layer, wherein the insulating protection layer covers the surfaces and the side faces of the first mesa and the second mesa, and comprises an insulating layer containing Al.

Optionally, forming an insulating protection layer over the light emitting epitaxial layer comprises sequentially depositing at least one insulating layer over the light emitting epitaxial layer, wherein a bottom insulating layer in direct contact with the light emitting epitaxial layer comprises an insulating layer comprising Al.

Optionally, forming an insulating protection layer over the light emitting epitaxial layer includes sequentially depositing at least one insulating layer over the light emitting epitaxial layer, the at least one insulating layer including an insulating layer containing Al.

Optionally, the method for preparing the ultraviolet LED chip further includes the following steps:

forming electrode vias in the insulating protection layer over the first mesa and the second mesa, respectively;

and respectively forming a first electrode and a second electrode in the electrode through holes, wherein the first electrode is electrically connected with the first semiconductor layer, and the second electrode is electrically connected with the second semiconductor layer.

Optionally, the forming of the first electrode and the second electrode in the electrode through hole respectively comprises the steps of:

forming a first metal contact layer above the first semiconductor layer, and forming a first electrode layer connected with the first metal contact layer in and above the electrode through hole;

and forming a metal reflecting layer above the second semiconductor layer, forming a second electrode layer connected with the metal reflecting layer in the electrode through hole and above the electrode through hole, and forming a reflecting structure of the ultraviolet LED chip by the insulating protective layer.

Optionally, sequentially depositing at least one insulating layer over the light emitting epitaxial layer includes alternately depositing a first insulating layer and a second insulating layer, wherein a refractive index of the first insulating layer is smaller than a refractive index of the second insulating layer, and the stacked structure of the insulating protective layer forms a reflection structure of the ultraviolet LED chip.

As described above, the ultraviolet LED chip and the method for manufacturing the same of the present invention have the following technical effects:

the ultraviolet LED chip comprises an insulating protection layer formed above a light-emitting epitaxial layer, wherein the insulating protection layer comprises an insulating layer containing Al, such as Al₂O₃AlN and AlF₃And the like, a single-layer structure containing Al may be formed by deposition, and a multilayer structure of stacked layers may also be formed. The adoption of the Al-containing insulating protection layer can reduce the replacement of Al ions in the epitaxial layer, can effectively compensate the Al ions missing from the epitaxial layer in the chip manufacturing process, and can not influence the Si doping in the epitaxial layer, thereby not damaging the epitaxial layer and avoiding the aging failure of the epitaxial layer.

Absorptivity ratio SiO of insulating protective layer containing Al in ultraviolet band₂When an Al-containing insulating layer having a multilayer structure is formed with a low content of Si-based materials such as/SiNx, an insulating film having a high and low refractive index can be formed in a laminated structure, thereby achieving the purpose of brightness enhancement.

In addition, for example, Al therein₂O₃High water resistance and better insulating property than SiO₂. Thermal conductivity ratio SiO of Al-containing film layer₂The Al-containing insulating protection layer is formed, so that the heat dissipation performance and the moisture resistance of the LED chip can be improved, and the aging failure of the LED chip can be effectively relieved.

Under the condition that the insulating protection layer is of a multilayer structure of insulating layers containing Al, a stacked structure with high and low refractive indexes is formed, and due to the different refractive indexes of different insulating layers to incident light, the effect of improving the brightness of the ultraviolet LED chip can be achieved.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

fig. 1 is a schematic structural diagram of an ultraviolet LED chip according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an ultraviolet LED chip according to a preferred embodiment of the first embodiment.

Fig. 3 is a schematic structural diagram of an ultraviolet LED chip according to another preferred embodiment of the first embodiment.

Fig. 4 is a schematic flow chart of a method for manufacturing an ultraviolet LED chip according to a second embodiment of the present invention.

Fig. 5 is a schematic view of a light emitting epitaxial layer formed in the method of fig. 4.

Fig. 6 is a schematic view of a structure in which an insulating protective layer is formed on the structure shown in fig. 5.

Fig. 7 is a view showing a structure of forming an electrode via hole in the insulating protective layer shown in fig. 6.

Fig. 8 is a schematic structural view of the insulating protective layer formed in the preferred embodiment of the second embodiment.

Fig. 9 is a schematic structural diagram of an insulating protection layer formed in another preferred embodiment of the second embodiment.

Reference numerals

100 substrate

100-11 light emitting epitaxial layer

100-1 first table top

100-2 second table top

101 first semiconductor layer

102 AlN layer

103 active layer

104 second semiconductor layer

105 insulating protective layer

1051 a first insulating layer

1052 second insulating layer

1053 third insulating layer

1054 electrode via

106 transparent conductive layer

107 metal reflective layer

1081 first electrode

1082 second electrode

109 first metal contact layer

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

In the following embodiments of the present invention, words indicating orientations, such as "upper", "lower", "left", "right", "horizontal", "vertical", etc., are referred to only to enable those skilled in the art to better understand the present invention, and should not be construed as limiting the present invention.

Example one

As shown in fig. 1 to 4, a light emitting epitaxial layer 100-11 in the present embodiment is formed over a substrate 100, and includes a first semiconductor layer 102, an active layer 103, and a second semiconductor layer 104 of an opposite conductivity type to the first semiconductor layer, which are sequentially formed over the substrate 100. The first semiconductor layer 102 forms a first mesa 100-1 (shown in fig. 4) of the light emitting epitaxial layer 100-11, and the active layer 103 and the second semiconductor layer 104 form a second mesa 100-2 of the light emitting epitaxial layer 100-11.

In a preferred embodiment of the present embodiment, the substrate may be a sapphire substrate, and the first semiconductor layer 102 may be an N-type semiconductor layer, which may include, for example, an AlN/AlGaN superlattice layer, a heavily doped N-type AlGaN layer, a lightly doped N-type AlGaN layer, and the like, which form a common N-type semiconductor layer of the ultraviolet LED chip. In a preferred embodiment, an AlN layer 101 is also formed between the substrate 100 and the first semiconductor layer 102. The second semiconductor layer 104 is a P-type AlGaN layer.

As shown in fig. 1, the ultraviolet LED chip further includes an insulating protection layer 105 formed on the surfaces and side surfaces of the first mesa 100-1 and the second mesa 100-2. In the present embodiment, the insulating protective layer is formed of an insulating material containing Al.

In the embodiment shown in FIG. 1, the insulating protective layer 105 has a single-layer structure, and the single-layer insulating protective layer may be made of, for example, Al₂O₃、AlN、AlON、AlF₃Etc. For example, the insulating protective layer may be made of Al₂O₃Form a. Experiments show that Al₂O₃Has high water resistance and better insulating property than SiO₂. Thermal conductivity ratio SiO of Al-containing film layer₂High of (2), Al₂O₃30W/m.k, and 150-200W/m.k AlN, so that the aging failure time can be extended.

As shown in fig. 1, the ultraviolet LED chip of the present embodiment further includes a first electrode 1081 and a second electrode 1082. An electrode through hole 1054 (shown with reference to fig. 6) is formed in the insulating protection layer 105, and a first electrode 1081 and a second electrode 1082 are formed in the electrode through hole 1054 and cover the electrode through hole. As shown in fig. 1, the first electrode 1081 includes a first metal contact layer 109 formed over the first semiconductor layer 102, and a first electrode layer (not shown) formed within and covering the electrode via hole. The first electrode 1081 is electrically connected to the first semiconductor layer 102 through the first metal contact layer 109. The second electrode 1082 includes a metal reflective layer 107 formed over the second semiconductor layer, and a second electrode layer (not shown) formed in and covering the electrode via hole. Preferably, a transparent conductive layer 106 may be further formed between the metal reflective layer 107 and the second semiconductor layer, and the transparent conductive layer 106 may be ITO (indium tin oxide). The second electrode 1082 is electrically connected to the second semiconductor layer through the metal reflective layer 107 and the transparent conductive layer 106.

In a preferred embodiment of the present embodiment, the insulating protection layer 105 forms a laminated structure including a plurality of insulating layers. As shown in fig. 2, in the preferred embodiment the insulating protection layer 105 includes a first insulating layer 1051, a second insulating layer 1052 and a third insulating layer 1053 formed in this order from the surface and side edges of the first and second mesas. The first insulating layer 1051, the second insulating layer 1052, and the third insulating layer 1053 are all insulating layers containing Al, for example, Al₂O₃、AlN、AlON、AlF₃And the like. Or in another preferred embodiment, the first insulating layer 1051 in contact with the first and second mesas is an Al-containing insulating layer, and the second insulating layer 1052 and the third insulating layer 1053 formed outside the first insulating layer may be Al-free insulating layers, for example, Si-containing insulating layers SiO₂Or SiN, etc.

In a more preferred embodiment, as shown in fig. 3, the insulating protection layer 105 is formed in a stacked structure formed of first insulating layers 1051 and second insulating layers 1052 which are alternately stacked. In the present preferred embodiment, the first insulating layer and the second insulating layer are both insulating layers containing Al, and the refractive index of the first insulating layer is smaller than that of the second insulating layer, whereby the stacked structure of the insulating protective layers forms the reflective structure of the ultraviolet LED chip. In a more preferred embodiment, the first insulating layer 1051 is AlF₃The second insulating layer may have a refractive index greater than AlF₃Is an AlN layer or Al₂O₃Layers or AlON layers, etc. The insulating protection layer 105 thus forms a laminated structure with high and low refractive indices due to the different refractive indices of the different insulating layers to the incident light (e.g., AlF)₃Has a refractive index of 1.35, Al₂O₃The refractive index of the aluminum nitride (AlN) is 1.6-1.7, and the refractive index of the AlN is 2.15), so that the effect of improving the brightness of the ultraviolet LED chip can be achieved.

In a more preferred embodiment, in which the first insulating layer 1051 is an Al-containing insulating layer, the second insulating layer 1052 may be an Al-free insulating layer, for example, may be a Si-containing insulating layer SiO₂Or SiN, etc.

The insulating protective layer of this embodiment adopts the insulating layer that contains Al, and the Al ion in the reducible epitaxial layer is replaced, and can not influence the Si doping in the epitaxial layer to can not harm the epitaxy, guarantee that the epitaxial layer can not consequently become invalid, and traditional adoption SiO₂And the film layer can cause the failure of the epitaxial layer due to the change of the Si doping content in the quantum hydrazine.

In addition, since both the insulating property and the heat dissipation property of the insulating layer containing Al are better than those of the insulating layer containing Si, the insulating protective layer of this embodiment can improve the heat dissipation property of the ultraviolet LED chip while protecting the epitaxial layer.

Example two

The embodiment also provides a method for preparing an ultraviolet LED chip, as shown in fig. 4, the method includes the following steps:

The light emitting epitaxial layer may be formed using a method commonly used in the art. As shown in fig. 5, for example, a substrate 100 is provided first, and then a first semiconductor layer 102, an active layer 103 and a second semiconductor layer 104 are sequentially deposited on the substrate 100. And etching the structure to expose the first semiconductor layer 102, thereby forming a first mesa 100-1, and forming a second mesa 100-2 shown in fig. 4 by the rest of the active layer and the second semiconductor layer, so as to form a light emitting epitaxial layer 100-11 of the ultraviolet LED chip. Preferably, the method further comprises forming a first metal contact layer 109 over the exposed first semiconductor layer 102. A metal reflective layer 107 is further formed over the second semiconductor layer 104, and more preferably, a transparent conductive layer 106 may also be deposited between the metal reflective layer and the second semiconductor layer.

In a preferred embodiment of the present embodiment, the substrate may be a sapphire substrate, and the first semiconductor layer 101 may be an N-type semiconductor layer, which may include, for example, an AlN/AlGaN superlattice layer, a heavily doped N-type AlGaN layer, a lightly doped N-type AlGaN layer, and the like, which form a common N-type semiconductor layer of the ultraviolet LED chip. In a preferred embodiment, an AlN layer 101 is also formed between the substrate 100 and the first semiconductor layer 102. The second semiconductor layer 104 is a P-type AlGaN layer, and the transparent conductive layer 106 thereon may be ITO (indium tin oxide).

Then, as shown in fig. 6, an insulating protection layer 105 is formed on the upper surfaces and the side surfaces of the first and second mesas 100-1 and 100-2. As shown in FIG. 5, the insulating protection layer 105 has a single-layer structure, and the single-layer insulating protection layer may be made of, for example, Al₂O₃、AlN、AlON、AlF₃Etc. For example, the insulating protective layer may be made of Al₂O₃The Deposition can be performed by an ALD (Atomic layer Deposition) process, a PECVD (Plasma Enhanced Chemical Vapor Deposition) process, or a physical Deposition (such as sputtering or electron evaporation), and the reaction temperature of the Deposition is controlled to be below 240 ℃, thereby reducing the displacement of Al particles in the active layer.

In addition, there are experiments to show that Al₂O₃Has high water resistance and better insulating property than SiO₂. Thermal conductivity ratio SiO of Al-containing film layer₂High of (2), Al₂O₃30W/m.k, and 150-200W/m.k AlN, so that the aging failure time can be extended.

Thereafter, as shown in fig. 7, electrode holes 1054 are formed in the insulating protective layer 105, and then conductive materials are deposited in the electrode holes 1054 to form the first and

second electrodes

1081 and 1082 shown in fig. 1, respectively. The first electrode 1081 and the second electrode 1082 cover the electrode hole 1054.

In a preferred embodiment of the present embodiment, a stacked structure including multiple insulating layers sequentially on the upper surfaces and the side surfaces of the first mesa and the second mesa, that is, in this preferred embodiment, the insulating protection layer 105 forms a stacked structure. As shown in fig. 8, the insulating protection layer 105 in the preferred embodiment includes a first insulating layer 1051, a second insulating layer 1052, and a third insulating layer 1053 formed in this order from the surface and side of the first and second mesas. Similarly, the first insulating layer 1051, the second insulating layer 1052 and the third insulating layer 1053 may be sequentially deposited by an ALD (Atomic layer Deposition) process, a PECVD (Plasma Enhanced Chemical Vapor Deposition) process or a physical Deposition (such as sputtering or electron evaporation).

In a preferred embodiment, the first insulating layer 1051, the second insulating layer 1052, and the third insulating layer 1053 are all Al-containing insulating layers, such as Al₂O₃、AlN、AlON、AlF₃And the like. Or in a further preferred embodiment, with the firstThe first insulating layer 1051 where the mesa and the second mesa are in contact is an Al-containing insulating layer, and the second insulating layer 1052 and the third insulating layer 1053 formed outside the first insulating layer may be Al-free insulating layers, for example, Si-containing insulating layers SiO₂Or SiN, etc.

In a more preferred embodiment, as shown in fig. 9, first and second insulating

layers

1051 and 1052 are alternately deposited over and laterally to the first and second mesas, and insulating protection layer 105 forms a stacked structure from the alternately deposited first and second insulating layers. In a preferred embodiment of the present embodiment, the first insulating layer and the second insulating layer are both insulating layers containing Al, and the refractive index of the first insulating layer is smaller than that of the second insulating layer, whereby the stacked structure of the insulating protective layers forms a reflective structure of the ultraviolet LED chip. In a more preferred embodiment, the first insulating layer 1051 is AlF₃The second insulating layer may be a layer having a refractive index greater than AlF₃Is an AlN layer or Al₂O₃Layers or AlON layers, etc. The insulating protection layer 105 thus forms a laminated structure with high and low refractive indices due to the different refractive indices of the different insulating layers to the incident light (e.g., AlF)₃Has a refractive index of 1.35, Al₂O₃The refractive index of the aluminum nitride (AlN) is 1.6-1.7, and the refractive index of the AlN is 2.15), so that the effect of improving the brightness of the ultraviolet LED chip can be achieved.

Thereafter, as shown in fig. 7, an electrode hole is formed in the insulating protective layer shown in fig. 8 or 9 and a first electrode and a second electrode are formed in the electrode hole (as shown in fig. 2 and 3).

The insulating protective layer of this embodiment adopts the insulating layer that contains Al, and the Al ion in the reducible epitaxial layer is displaced, and can not influence the Si doping in the epitaxial layer to can not harm the epitaxy, guarantee that the epitaxial layer can not consequently become invalid, and traditional LED chip generally adopts SiO₂And the film layer can cause the failure of the epitaxial layer due to the change of the Si doping content in the quantum hydrazine.

In addition, since both the insulating property and the heat dissipation property of the insulating layer containing Al are better than those of the insulating layer containing Si, the insulating protective layer of the embodiment of the present year can improve the heat dissipation property of the ultraviolet LED chip while protecting the epitaxial layer.

The foregoing embodiments are merely illustrative of the principles of this invention and its efficacy, rather than limiting it, and various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the invention, which is defined in the appended claims.

Claims

1. A light-emitting diode, characterized in that, comprising:

a light-emitting epitaxial layer, comprising a first semiconductor layer, an active layer formed over the first semiconductor layer, and a second semiconductor layer formed over the active layer and having an opposite conductivity type to the first semiconductor layer;

and an insulating protective layer formed at least on the side of the light-emitting epitaxial layer, the insulating protective layer includes at least two insulating layers, the layer close to the light-emitting epitaxial layer is the first insulating layer, and the remaining insulating layers are far away from the light-emitting epitaxial layer. layer, wherein the thermal conductivity of the first insulating layer is higher than the thermal conductivity of the remaining insulating layers.

2 . The light emitting diode of claim 1 , wherein the first insulating layer is in direct contact with the light emitting epitaxial layer. 3 .

3 . The light emitting diode of claim 2 , wherein the first insulating layer contains Al element. 4 .

4. The light emitting diode of claim 3, wherein the first insulating layer is formed of at least one of Al ₂ O ₃ , AlN, AlON and AlF ₃ .

5 . The light emitting diode according to claim 1 , wherein the remaining insulating layers formed outside the first insulating layer are insulating layers that do not contain Al. 6 .

6. The light emitting diode of claim 5, wherein the remaining insulating layers are formed of _SiO2 or SiN.

7 . The light emitting diode according to claim 1 , wherein the insulating protection layer has electrode through holes, and the ultraviolet LED chip further comprises a first electrode and a second electrode formed through the electrode through holes, and the The first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the second semiconductor layer.

8 . The light emitting diode of claim 7 , wherein the first electrode comprises a first metal contact layer formed over the first semiconductor layer and a first metal contact layer formed in the electrode through hole and covering the a first electrode layer in which an electrode through hole is connected to the first metal contact layer; the second electrode includes a metal reflective layer formed above the second semiconductor layer and a metal reflective layer formed in the electrode through hole and covering the The electrode through hole is connected to the second electrode layer of the metal reflective layer.

9. A method for preparing a light-emitting diode, comprising the following steps:

forming a light-emitting epitaxial layer, and sequentially depositing a first semiconductor layer, an active layer, and a second semiconductor layer of opposite conductivity type to the first semiconductor layer;

An insulating protective layer is formed on the side of the light-emitting epitaxial layer, the insulating protective layer includes at least two insulating layers, the layer close to the light-emitting epitaxial layer is a first insulating layer, and the remaining insulating layers are far from the light-emitting epitaxial layer, The thermal conductivity of the first insulating layer is higher than the thermal conductivity of the remaining insulating layers.

10 . The method for fabricating a light emitting diode according to claim 9 , wherein the first insulating layer and the remaining insulating layers have different fabrication processes. 11 .

11 . The method for manufacturing a light emitting diode according to claim 9 , wherein the insulating protective layer is formed by an atomic layer deposition process, a plasma enhanced chemical vapor deposition process, or a physical deposition process. 12 .

12 . The manufacturing method of a light emitting diode according to claim 9 , wherein forming an insulating protective layer on the side surface of the light emitting epitaxial layer comprises a first insulating layer in direct contact with the light emitting epitaxial layer, and the first insulating layer is in direct contact with the light emitting epitaxial layer. 13 . The layer contains Al element.

13 . The method for preparing a light-emitting diode according to claim 12 , wherein the first insulating layer in direct contact with the light-emitting epitaxial layer is made of at least one of Al ₂ O ₃ , AlN, AlON and AlF ₃ . form.

14. The method for preparing a light-emitting diode according to claim 9, wherein forming an insulating protective layer on the side of the light-emitting epitaxial layer comprises the remaining insulating layers covering the outside of the first insulating layer, and the remaining insulating layers are not. Contains Al element.

15 . The method for manufacturing a light-emitting diode according to claim 14 , wherein forming an insulating protective layer on the side of the light-emitting epitaxial layer comprises the remaining insulating layers covering the outside of the first insulating layer, and the remaining insulating layers are composed of 15 . _SiO2 or SiN formation.

16. The method for preparing a light-emitting diode according to claim 9, further comprising the following steps:

forming electrode through holes in the insulating protection layer above the first mesa and the second mesa, respectively;

A first electrode and a second electrode are respectively formed in the electrode through holes, the first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the second semiconductor layer.

17 . The method for manufacturing a light emitting diode according to claim 16 , wherein forming the first electrode and the second electrode in the electrode through hole respectively comprises the following steps: 18 .

A first metal contact layer is formed above the first semiconductor layer, and a first electrode layer connected to the first metal contact layer is formed in the electrode through hole and above the electrode through hole;

A metal reflection layer is formed above the second semiconductor layer, and a second electrode layer connected to the metal reflection layer is formed in the electrode through hole and above the electrode through hole.