LED epitaxial structure, preparation method thereof and LED chip

Abstract

The application provides an LED epitaxial structure and a preparation method thereof and an LED chip, wherein the MQW layer of the LED epitaxial structure comprises quantum barriers and quantum wells which are alternately and layerwisely grown along a first direction, the quantum barriers comprise a plurality of InGaN / GaN / AlGaN layers, and the two contact surfaces of the quantum barriers are respectively provided with GaN layers; the InGaN / GaN / AlGaN layers produce multi-stage scattering to electrons, reduce the electron migration rate, and increase the probability that the electrons are captured by the MQW; meanwhile, a polarization electric field (P→N) in a counter-growth direction is formed between the layers of the InGaN / GaN / AlGaN, multi-stage acceleration is generated to holes, deceleration is generated to electrons, the injection efficiency of the holes is increased, and the electron overflow is reduced, so that the carrier distribution is balanced, the radiation recombination rate is increased, and the light-emitting efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of light-emitting diodes, and more particularly to an LED epitaxial structure, its fabrication method, and an LED chip. Background Technology

[0002] In recent years, III-V group nitrides have received widespread attention and application in the fields of electrical and optical engineering due to their excellent physical and chemical properties (large bandgap, high breakdown electric field, high electron saturation mobility, etc.). However, in practical applications, due to limitations in materials, structure, and processes, the large-scale application of various emerging LED products still faces many problems. For example, insufficient electron binding leads to severe leakage; low hole injection efficiency limits further improvement in luminous efficiency; and strong polarization fields caused by large lattice mismatch, etc. These all hinder the efficient recombination of charge carriers in the active region, posing a significant challenge to the large-scale commercialization of LEDs. Therefore, reducing electron leakage, increasing hole injection efficiency, weakening strong polarization fields, and promoting efficient recombination of charge carriers in the active region have become key to improving LED luminous efficiency.

[0003] Current quantum barrier structure designs, which involve growing intercalation layers (AlGaN, AlInGaN) between quantum barriers or employing stepped quantum barriers, aim to increase the conduction band barrier height, reduce electron overflow, and thus improve luminescence efficiency. However, while the quantum barrier intercalation layer / stepped barrier utilizes a high barrier to block electrons, this high barrier also hinders hole injection to some extent. Furthermore, excessive lattice mismatch between the intercalation layer and GaN inevitably affects the subsequent MQW crystal growth quality and reduces device reliability.

[0004] In view of this, the inventors have specifically designed an LED epitaxial structure and its preparation method, as well as an LED chip, which leads to this invention. Summary of the Invention

[0005] The purpose of this invention is to provide an LED epitaxial structure and its preparation method, as well as an LED chip, to reduce electron overflow and thus improve the luminous efficiency of the LED.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An LED epitaxial structure, comprising: A substrate, and an N-type semiconductor layer, an MQW layer, a last quantum barrier layer, and a P-type semiconductor layer sequentially stacked on the surface of the substrate; The MQW layer comprises quantum barriers and quantum wells that are alternately stacked along a first direction. The quantum barriers include several groups of InGaN / GaN / AlGaN layers to form a hierarchical scattering of electrons and a polarized electric field in the reverse growth direction. The first direction is perpendicular to the substrate and points from the substrate to the N-type semiconductor layer.

[0007] Preferably, the two contact surfaces of the quantum barrier are each provided with a GaN layer.

[0008] Preferably, a protective layer is provided between the N-type semiconductor layer and the MQW layer, and the protective layer comprises alternately stacked second N-type GaN layers and UGaN layers.

[0009] Preferably, the N-type doping concentration of the second N-type GaN layer is lower than the N-type doping concentration of the N-type semiconductor layer.

[0010] Preferably, the last quantum barrier layer comprises a GaN-AlGaN-AlN composite layered structure.

[0011] Preferably, in the last quantum barrier layer, the thickness of the GaN layer is not less than the thickness of the AlGaN layer.

[0012] Preferably, in the last quantum barrier layer, the thickness of the AlN layer is not greater than the thickness of the AlGaN layer.

[0013] Preferably, the N-type semiconductor layer comprises several groups of N-type doped AlGaN / GaN layers.

[0014] This invention also provides a method for preparing an LED epitaxial structure, comprising: Provide a substrate; An N-type semiconductor layer, a protective layer, an MQW layer, a last quantum barrier layer, and a P-type semiconductor layer are sequentially grown on the surface of the substrate. The MQW layer comprises quantum barriers and quantum wells that are alternately stacked along the growth direction. The quantum barriers consist of several groups of InGaN / GaN / AlGaN layers to form a polarization electric field in the opposite growth direction. The two contact surfaces of the quantum barrier are each provided with a GaN layer.

[0015] Preferably, the protective layer comprises alternately stacked second N-type GaN layers and UGaN layers; and the N-type doping concentration of the second N-type GaN layer is lower than the N-type doping concentration of the N-type semiconductor layer; The N-type semiconductor layer includes several groups of N-type doped AlGaN / GaN layers; The last quantum barrier layer comprises a GaN-AlGaN-AlN composite layered structure.

[0016] Preferably, during the discontinuous growth of the In component in the quantum barrier through the InGaN / GaN / AlGaN layer, the incorporation of H2 is maintained, and the incorporation of In and H2 is in opposite states.

[0017] The present invention also provides an LED chip, comprising: The LED epitaxial structure described in any of the above items; An N-type electrode is formed in an ohmic contact with the N-type semiconductor layer; The P-type electrode forms an ohmic contact with the P-type semiconductor layer.

[0018] As can be seen from the above technical solution, the LED epitaxial structure provided by the present invention includes a quantum barrier and a quantum well that are alternately stacked along a first direction in the MQW layer. The quantum barrier includes several groups of InGaN / GaN / AlGaN layers. Furthermore, GaN layers are respectively provided on the two contact surfaces of the quantum barrier. The InGaN / GaN / AlGaN layers generate multi-level scattering of electrons, reducing the electron migration rate and increasing the probability of electrons being captured by the MQW. At the same time, a polarized electric field (P→N) in the opposite growth direction is formed between the InGaN / GaN / AlGaN layers, which generates multi-level acceleration of holes and deceleration of electrons, increasing the hole injection efficiency and reducing electron overflow, thereby balancing the carrier distribution, increasing the radiative recombination rate, and improving the luminous efficiency.

[0019] Secondly, a protective layer is provided between the N-type semiconductor layer and the MQW layer, and the protective layer includes alternately stacked second N-type GaN layers and UGaN layers. Further, the N-type doping concentration of the second N-type GaN layer is lower than the N-type doping concentration of the N-type semiconductor layer. This achieves a transition in N-type doping between the N-type semiconductor layer and the MQW layer (high doping-low doping-no doping); simultaneously, it increases the LED's electrostatic discharge (ESD) immunity, thereby improving the overall reliability of the device.

[0020] Then, by setting the last quantum barrier layer to include a GaN-AlGaN-AlN composite layered structure, a higher barrier gradient can be formed to reduce electron overflow, and a relatively thin thickness can be achieved, which is conducive to holes tunneling into the MQW layer. Then, the subsequent electron blocking layer can be removed, weakening the band bending of the electron blocking layer and the last quantum barrier layer, reducing the valence band barrier height, and increasing hole injection. Especially under low current injection, the beneficial effect of increasing hole injection is greater than the blocking effect on electrons.

[0021] The present invention also provides a method for preparing an LED epitaxial structure, which achieves the above-mentioned technical effects while being simple to operate and easy to implement.

[0022] Furthermore, the present invention provides a method for fabricating an LED epitaxial structure, in which H2 is incorporated during the discontinuous growth of the In component in the quantum barrier through the InGaN / GaN / AlGaN layer, and the incorporation of In and H are in opposite states. In one embodiment, H2 incorporation is achieved by gradually introducing H. Since H2 is detrimental to In incorporation, the purpose of gradually introducing H is to modify the InGaN-GaN interface to make the entire interface smoother and the transition more natural; at the same time, it can also reduce the formation of In clusters in the InGaN layer and improve the crystal quality of the entire quantum barrier.

[0023] The present invention also provides an LED chip formed using the aforementioned LED epitaxial structure, which has a simple structure and greatly improves the luminous efficiency and reliability of the LED chip. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will describe the embodiments. The accompanying drawings used in the description of embodiments or prior art are briefly introduced below. It is obvious that... The accompanying drawings are merely embodiments of the present invention. For those skilled in the art, they will not reveal the full meaning of the invention. Provided that creative effort is put in, other accompanying drawings can be obtained based on the provided drawings.

[0025] Figure 1 This is a schematic diagram of the LED epitaxial structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the MQW layer structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an N-type semiconductor layer provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the protective layer provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the last quantum barrier layer provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the growth control method of the quantum barrier provided in an embodiment of the present invention; Symbol explanations in the diagram: 1. Substrate; 2. Buffer layer; 3. Unintentionally doped layer. 4. N-type semiconductor layer; 41. N-type doped AlGaN layer; 42. N-type doped GaN layer; 5. Protective layer; 51. Second N-type GaN layer; 52. UGaN layer; 6. MQW layer, 60. GaN layer, 61. Quantum barrier, 61.1. InGaN layer, 61.2. GaN layer, 61.3. AlGaN layer, 62. InGaN quantum well; 7. The last quantum barrier layer; 71. GaN layer; 72. AlGaN layer; 73. AlN layer; 8. P-type semiconductor layer. Detailed Implementation

[0026] To make the content of this invention clearer, the following description, in conjunction with the accompanying drawings, further illustrates the invention. This invention is not limited to this specific embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0027] like Figure 1 , Figure 2 The aforementioned LED epitaxial structure includes: Substrate 1, and N-type semiconductor layer 4, MQW layer 6, last quantum barrier layer and P-type semiconductor layer sequentially stacked on the surface of substrate 1; The MQW layer 6 includes quantum barriers and quantum wells that are alternately stacked along a first direction. The quantum barriers include several groups of InGaN / GaN / AlGaN (61.1, 61.2, 61.3) layers to form a hierarchical scattering of electrons and a polarized electric field in the reverse growth direction. The first direction is perpendicular to the substrate 1 and points from the substrate 1 to the N-type semiconductor layer 4.

[0028] It is worth mentioning that the type of substrate 1 is not limited in this embodiment. For example, substrate 1 includes any one of sapphire, silicon carbide, silicon, gallium nitride, and aluminum nitride. In addition, the types of N-type semiconductor layer 4 and P-type semiconductor layer are also not limited. For example, N-type semiconductor layer 4 can be, but is not limited to, gallium nitride layer, and correspondingly, P-type semiconductor layer can be, but is not limited to, gallium nitride layer.

[0029] Furthermore, based on the above embodiments of the present invention, the two contact surfaces of the quantum barrier are respectively provided with GaN layers 60.

[0030] Furthermore, based on the above embodiments of the present invention, such as Figure 4 As shown, a protective layer is provided between the N-type semiconductor layer 4 and the MQW layer 6, and the protective layer includes alternately stacked second N-type GaN layer 51 and UGaN layer 52.

[0031] Furthermore, based on the above embodiments of the present invention, the N-type doping concentration of the second N-type GaN layer 51 is less than the N-type doping concentration of the N-type semiconductor layer 4.

[0032] Furthermore, based on the above embodiments of the present invention, such as Figure 5 As shown, the last quantum barrier layer consists of GaN-AlGaN-AlN composite layered structures (71, 72, 73).

[0033] Furthermore, based on the above embodiments of the present invention, in the last quantum barrier layer, the thickness 71 of the GaN layer is not less than the thickness of the AlGaN layer 72.

[0034] Furthermore, based on the above embodiments of the present invention, in the last quantum barrier layer, the thickness of the AlN layer 73 is not greater than the thickness of the AlGaN layer 72.

[0035] Furthermore, based on the above embodiments of the present invention, such as Figure 3 As shown, the N-type semiconductor layer 4 includes several groups of N-type doped AlGaN / GaN layers (41, 42).

[0036] This invention also provides a method for fabricating an LED epitaxial structure, comprising: S01, Provide a substrate 1; In this step, the substrate 11 includes, but is not limited to, a sapphire substrate 11.

[0037] S02, A buffer layer 2, an unintentionally doped layer 3, and an N-type semiconductor layer 4 are grown on the surface of the substrate 1, wherein the N-type semiconductor layer 4 includes several groups of N-type doped AlGaN / GaN layers; In this step, substrate 1 is placed in the MOCVD reaction chamber and hydrogenated for about 5 minutes at a temperature of about 1100°C by introducing high-purity hydrogen gas. Then, the temperature is lowered to about 960°C, and Al and N sources are introduced to grow an undoped AlN buffer layer 2 with a thickness of about 10 nm.

[0038] Continue heating to 1050℃-1100℃, turn off the Al source, and introduce the TMGa source to grow an undoped GaN layer of 2.0μm-2.5μm. The purpose is to reduce the lattice mismatch between the sapphire substrate 1 and the subsequent film material by growing a high-quality unintentionally doped layer 3.

[0039] Next, an Al source is introduced, and the ambient temperature is maintained at 980℃-1020℃ to grow an AlGaN layer with a thickness of approximately 10nm-20nm. The Al source is then turned off, and silane is introduced to grow a GaN layer of approximately 5nm-10nm, doped with an N-type dopant (such as Si) at a doping concentration of 5*10⁻⁶. 18 cm -3 -10*10 18 cm -3These two layers grow alternately, forming 10-20 cycles, and finally obtaining an N-type semiconductor layer 4 of N-type doped AlGaN / GaN (41, 42).

[0040] S03. A protective layer is formed on the surface of the N-type semiconductor layer 4, and the protective layer includes alternately stacked second N-type GaN layer 51 and UGaN layer 52; further, in this embodiment, the N-type doping concentration of the second N-type GaN layer 51 is less than the N-type doping concentration of the N-type semiconductor layer 4. Based on step S02 above, the flux of the N-type dopant (such as Si) is reduced to grow low-doped GaN (e.g., doping concentration less than 5*10). 17 cm -3 The second N-type GaN layer 51 is grown to a thickness of 10-20 nm. Si is then turned off, and a corresponding 10-20 nm undoped UGaN layer is grown. This process is repeated, alternating between growing the second N-type GaN layer 51 and the UGaN layer 52 for 4-8 cycles. This achieves the N-type doping transition (high doping-low doping-undoped) between the N-type semiconductor layer 4 and the MQW layer 6. Simultaneously, it increases the LED's electrostatic discharge (ESD) immunity, thereby improving the overall reliability of the device.

[0041] S04. An MQW layer 6 is formed on the surface of the protective layer; wherein the MQW layer 6 includes quantum barriers and quantum wells that are alternately stacked along the growth direction, the quantum wells including an InGaN layer 62; the quantum barriers include several groups of InGaN / GaN / AlGaN (61.1, 61.2, 61.3) layers, and the two contact surfaces of the quantum barriers are GaN layers 60 respectively. In this step, such as Figure 6As shown, firstly, Ga and N sources are introduced to grow a 1-3 nm thick surface GaN layer 60; then, an In source is introduced for t0 to grow an InGaN layer 61.1; then the In source is turned off and a Ga source is introduced for t1 to grow a GaN layer 61.2; then an Al source is introduced for t2 to grow an AlGaN layer 61.3. One cycle is T = t0 + t1 + t2, and the InGaN / GaN / AlGaN layers (61.1, 61.2, 61.3) are grown alternately for 3-5 cycles, with a thickness of M. Then, the In source is turned off, and another 1-3 nm thick surface GaN layer 60 is grown, thus forming a complete quantum barrier (QB) with a total thickness between 10-20 nm, including the endpoint values. Furthermore, based on the above embodiments of the present invention, during the discontinuous growth of the In component in the quantum barrier through the InGaN / GaN / AlGaN layers (61.1, 61.2, 61.3), the incorporation of H2 is maintained, and the incorporation of In and H are in opposite states. In one embodiment, the incorporation of H2 is achieved by gradually changing the H flow. Since H2 is not conducive to the incorporation of In, the purpose of gradually changing the H flow is to modify the InGaN-GaN interface to make the entire interface smoother and the transition more natural; at the same time, it can also reduce the formation of In clusters in the InGaN layer and improve the crystal quality of the entire quantum barrier. Then, a 2-4 nm InGaN quantum well 62 is grown. Repeat the above cycle for 5-10 cycles to form MQW layer 6.

[0042] S05. A last quantum barrier layer is formed on the surface of the MQW layer 6; the last quantum barrier layer includes a GaN-AlGaN-AlN composite layered structure (71, 72, 73); and the thickness of the GaN layer 71 is not less than the thickness of the AlGaN layer 72; the thickness of the AlN layer 73 is not greater than the thickness of the AlGaN layer 72.

[0043] In this step, the In source is turned off, and a GaN layer is grown first 71; Then an Al source was introduced to grow an AlGaN layer 72; Finally, the Ga source was turned off, and a thin AlN layer 73 was grown to form the last quantum barrier layer. Furthermore, the thickness of the last quantum barrier layer is 10-15 nm, of which the thickness of the GaN layer is 5-10 nm, and the thickness of the AlN layer is no greater than that of the AlGaN layer.

[0044] S06. Form a P-type semiconductor layer 8 on the surface of the last quantum barrier layer; In this step, the temperature is adjusted to 900-1000℃, and a TMGa source, a nitrogen source, and magnesia-diocene are introduced to grow a p-type GaN layer with a thickness of 100-150 nm and a doping concentration of 5*10⁻⁶. 18 cm -3 Up to 10 * 10 18 cm -3 Ultimately, a P-type semiconductor layer is formed.

[0045] This invention also provides an LED chip, comprising: The LED epitaxial structure described in any of the above items; The N-type electrode forms an ohmic contact with the N-type semiconductor layer 4; The P-type electrode forms an ohmic contact with the P-type semiconductor layer.

[0046] As can be seen from the above technical solution, the LED epitaxial structure provided by the present invention includes a quantum barrier and a quantum well that are alternately stacked along a first direction in the MQW layer 6. The quantum barrier includes several groups of InGaN / GaN / AlGaN layers. Furthermore, GaN layers are respectively provided on the two contact surfaces of the quantum barrier. The InGaN / GaN / AlGaN layers generate multi-level scattering of electrons, reducing the electron migration rate and increasing the probability of electrons being captured by the MQW. At the same time, a polarized electric field (P→N) in the opposite growth direction is formed between the InGaN / GaN / AlGaN layers, which generates multi-level acceleration of holes and deceleration of electrons, increasing the hole injection efficiency and reducing electron overflow, thereby balancing the carrier distribution, increasing the radiative recombination rate, and improving the luminous efficiency.

[0047] Secondly, a protective layer is provided between the N-type semiconductor layer 4 and the MQW layer 6, and the protective layer includes alternately stacked second N-type GaN layers 51 and UGaN layers 52. Further, the N-type doping concentration of the second N-type GaN layer 51 is lower than the N-type doping concentration of the N-type semiconductor layer 4. This achieves a transition in N-type doping between the N-type semiconductor layer 4 and the MQW layer 6 (high doping-low doping-no doping); simultaneously, it increases the LED's electrostatic discharge (ESD) immunity, thereby improving the overall reliability of the device.

[0048] Then, by setting the last quantum barrier layer to include a GaN-AlGaN-AlN composite layered structure, a higher barrier gradient can be formed to reduce electron overflow, and a relatively thin thickness can be achieved, which is beneficial for holes to tunnel into the MQW layer 6. Then, the subsequent electron blocking layer can be removed, weakening the band bending between the electron blocking layer and the last quantum barrier layer, reducing the valence band barrier height, and increasing hole injection. Especially under low current injection, the beneficial effect of increasing hole injection is greater than the blocking effect on electrons.

[0049] The present invention also provides a method for preparing an LED epitaxial structure, which achieves the above-mentioned technical effects while being simple to operate and easy to implement.

[0050] Furthermore, the present invention provides a method for fabricating an LED epitaxial structure, in which H2 is incorporated during the discontinuous growth of the In component in the quantum barrier through the InGaN / GaN / AlGaN layer, and the incorporation of In and H are in opposite states. In one embodiment, H2 incorporation is achieved by gradually introducing H. Since H2 is detrimental to In incorporation, the purpose of gradually introducing H is to modify the InGaN-GaN interface to make the entire interface smoother and the transition more natural; at the same time, it can also reduce the formation of In clusters in the InGaN layer and improve the crystal quality of the entire quantum barrier.

[0051] The present invention also provides an LED chip formed using the aforementioned LED epitaxial structure, which has a simple structure and greatly improves the luminous efficiency and reliability of the LED chip.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0053] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An LED epitaxial structure, characterized in that, include: A substrate, and an N-type semiconductor layer, a protective layer, an MQW layer, a last quantum barrier layer, and a P-type semiconductor layer sequentially stacked on the surface of the substrate; The MQW layer comprises quantum barriers and quantum wells that are alternately stacked along a first direction. The quantum barriers comprise several groups of InGaN / GaN / AlGaN layers to form a hierarchical scattering of electrons and a polarized electric field in the reverse growth direction. The first direction is perpendicular to the substrate and points from the substrate to the N-type semiconductor layer. The two contact surfaces of the quantum barrier are each provided with a GaN layer.

2. The LED epitaxial structure according to claim 1, characterized in that, A protective layer is provided between the N-type semiconductor layer and the MQW layer, and the protective layer comprises alternating stacked second N-type GaN layers and UGaN layers.

3. The LED epitaxial structure according to claim 2, characterized in that, The N-type doping concentration of the second N-type GaN layer is lower than that of the N-type semiconductor layer.

4. The LED epitaxial structure according to claim 1, characterized in that, The last quantum barrier layer consists of a GaN-AlGaN-AlN composite layered structure.

5. The LED epitaxial structure according to claim 1, characterized in that, In the last quantum barrier layer, the thickness of the GaN layer is not less than the thickness of the AlGaN layer.

6. The LED epitaxial structure according to claim 4, characterized in that, In the last quantum barrier layer, the thickness of the AlN layer is no greater than the thickness of the AlGaN layer.

7. The LED epitaxial structure according to claim 1, characterized in that, The N-type semiconductor layer includes several groups of N-type doped AlGaN / GaN layers.

8. A method for fabricating an LED epitaxial structure, characterized in that, include: Provide a substrate; An N-type semiconductor layer, a protective layer, an MQW layer, a last quantum barrier layer, and a P-type semiconductor layer are sequentially grown on the surface of the substrate. The MQW layer includes quantum barriers and quantum wells that are alternately stacked along the growth direction. The quantum barriers include several groups of InGaN / GaN / AlGaN layers to form a hierarchical scattering of electrons and a polarization electric field in the opposite growth direction. The two contact surfaces of the quantum barrier are each provided with a GaN layer.

9. The method for preparing an LED epitaxial structure according to claim 8, characterized in that, The protective layer comprises alternately stacked second N-type GaN layers and UGaN layers; and the N-type doping concentration of the second N-type GaN layer is lower than the N-type doping concentration of the N-type semiconductor layer. The N-type semiconductor layer includes several groups of N-type doped AlGaN / GaN layers; The last quantum barrier layer comprises a GaN-AlGaN-AlN composite layered structure.

10. The method for preparing an LED epitaxial structure according to claim 8, characterized in that, During the discontinuous growth of the In component in the quantum barrier through the InGaN / GaN / AlGaN layer, the incorporation of H2 is maintained, and the incorporation of In and H2 is in opposite states.

11. An LED chip, comprising: The LED epitaxial structure according to any one of claims 1-7; An N-type electrode is formed in an ohmic contact with the N-type semiconductor layer; The P-type electrode forms an ohmic contact with the P-type semiconductor layer.

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