CN116845158A - LED epitaxial wafer, preparation method thereof and LED - Google Patents

Abstract

The invention discloses a light-emitting diode epitaxial wafer, a preparation method thereof, and an LED. The light-emitting diode epitaxial wafer includes a substrate. The substrate is sequentially provided with a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, and a uniform wavelength layer. property control layer, multiple quantum well layer, electron blocking layer, and P-type semiconductor layer; the wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer, and the compressive stress providing layer includes a first AlN layer deposited in sequence , AlGaN layer, and second AlN layer. The tensile stress providing layer includes a first InGaN layer, an InN layer, and a second InGaN layer deposited in sequence. The light-emitting diode epitaxial wafer provided by the invention can improve the uniformity of the light-emitting wavelength of the light-emitting diode.

Description

Light-emitting diode epitaxial wafer and preparation method thereof, LED

Technical field

The present invention relates to the field of optoelectronic technology, and in particular to a light-emitting diode epitaxial wafer and a preparation method thereof, and an LED.

Background technique

At present, GaN-based light-emitting diodes have been widely used in the field of solid-state lighting and display, attracting more and more people's attention. GaN-based light-emitting diodes have achieved industrial production and are used in backlights, lighting, landscape lights, etc.

The epitaxial structure has a great influence on the photoelectric performance of light-emitting diodes. A traditional light-emitting diode epitaxial wafer includes a substrate, and a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a multi-quantum well layer, an electron blocking layer, and a P-type semiconductor layer grown sequentially on the substrate; As the active area, the well layer is the core structure of the light-emitting diode. The existing multi-quantum well layer is composed of an InGaN potential well layer and a GaN quantum barrier layer periodically stacked. The traditional multi-quantum well layer has the following problems:

At present, domestic MOCVD using sapphire patterned substrates to grow LED epitaxial wafers will encounter quality fluctuations due to switching between different types of sapphire patterned substrates. Among them, due to differences in substrate pattern depth, spacing and other specifications, the product growth process Medium warpage changes affect the uniformity of wavelength distribution. Products grown using original conditions are prone to concentric circles with longer or shorter wavelengths, resulting in non-concentrated wavelength distribution. The produced chips have scattered wavelength distribution and low bin rate. Low. The existing technical solution is mainly to adjust the stress by modifying the growth parameters of the nucleation layer. The significant disadvantage is that it is far away from the light-emitting active area, that is, the multi-quantum well layer, and the uniformity of the output wavelength is difficult to control. Moreover, the multi-quantum well layer InGaN potential well layer affects the luminous efficiency due to In segregation problem.

Contents of the invention

The technical problem to be solved by the present invention is to provide a light-emitting diode epitaxial wafer that can improve the uniformity of the light-emitting wavelength of the light-emitting diode.

The technical problem to be solved by the present invention is to provide a method for preparing a light-emitting diode epitaxial wafer, which has a simple process and can stably produce a light-emitting diode epitaxial wafer with good luminous efficiency.

In order to solve the above technical problems, the present invention provides a light-emitting diode epitaxial wafer, which includes a substrate. The substrate is sequentially provided with a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity control layer, and a multi-quantum semiconductor layer. Well layer, electron blocking layer, P-type semiconductor layer;

The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited sequentially. The tensile stress providing layer includes a sequentially deposited The first InGaN layer, the InN layer, and the second InGaN layer.

In one embodiment, the thickness of the compressive stress providing layer is 10nm~100nm;

The thickness of the tensile stress providing layer is 10nm~100nm.

In one embodiment, the thickness of the first AlN layer or the second AlN layer is 5nm~20nm;

The thickness of the AlGaN layer is 10nm~80nm.

In one implementation, the Al composition of the AlGaN layer is 0.2 to 0.7.

In one implementation, the thickness of the first InGaN layer or the second InGaN layer is 10nm~50nm;

The thickness of the InN layer is 5nm~20nm.

In one implementation, the In composition of the first InGaN layer or the second InGaN layer is 0.1 to 0.5.

In order to solve the above problems, the present invention also provides a method for preparing a light-emitting diode epitaxial wafer, which includes the following steps:

S1. Prepare the substrate;

S2. Deposit sequentially on the substrate a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity control layer, a multi-quantum well layer, an electron blocking layer, and a P-type semiconductor layer;

The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited sequentially. The tensile stress providing layer includes a sequentially deposited The first InGaN layer, the InN layer, and the second InGaN layer.

In one embodiment, the compressive stress providing layer is made by the following method:

Control the temperature of the reaction chamber at 1000℃~1100℃ and the pressure of the reaction chamber at 100torr~500torr. Pass in the Al source and N source to complete the deposition of the first AlN layer. Then feed in the Al source, Ga source and N source to complete. After the deposition of the AlGaN layer, the Al source and the N source are introduced to complete the deposition of the second AlN layer.

In one embodiment, the tensile stress providing layer is made by the following method:

The temperature of the reaction chamber is controlled at 800°C~900°C, and the pressure of the reaction chamber is controlled at 100torr~500torr. The Ga source, In source, and N source are introduced to complete the deposition of the first InGaN layer, and then the In source and N source are introduced. , to complete the deposition of the InN layer, and then pass in the Ga source, In source, and N source to complete the deposition of the second InGaN layer.

Correspondingly, the present invention also provides an LED, which includes the above-mentioned light-emitting diode epitaxial wafer.

Implementing the present invention has the following beneficial effects:

In the light-emitting diode epitaxial wafer provided by the invention, a wavelength uniformity control layer of a specific structure is inserted between the N-type semiconductor layer and the multi-quantum well layer. The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited in sequence, and the tensile stress providing layer includes a first InGaN layer, an InN layer, and a second InGaN layer deposited in sequence.

In the compressive stress providing layer, since Al atoms are small and AlN and AlGaN materials have small lattice constants, compressive stress can be provided to the epitaxial layer. The compressive stress providing layer is an AlN/AlGaN/AlN sandwich structure. The AlN layer at high temperatures has a high density. However, continuous high-temperature growth of an AlN layer that is too thick will easily cause cracks, so the middle AlGaN material serves as a buffer. The AlN/AlGaN/AlN sandwich structure has a good blocking effect on underlying defects, causing dislocation defects to be distorted and annihilated in this layer, preventing defects from accumulating into the multi-quantum well layer and affecting the uniform distribution of the In component.

In the tensile stress providing layer, due to the large In atoms and the large lattice quality of InN and InGaN materials, tensile stress can be provided. The tensile stress providing layer is an InGaN/InN/InGaN sandwich structure, which can not only alleviate the problem of poor stability of InN materials, but also has a small lattice mismatch with the InGaN material of the potential well layer in the multi-quantum well layer, which can reduce the number of multi-quantum wells. The compressive stress on the well layer prevents uneven distribution of In components caused by excessive compressive stress, thereby avoiding aggravation of In segregation.

In summary, the wavelength uniformity control layer proposed by the present invention can adjust the warpage before the growth of the multi-quantum well layer, more accurately control the warpage during the growth of the multi-quantum well layer, and increase the uniformity of the luminescence wavelength. At the same time, the defects of the multi-quantum well layer are reduced, the stress during the growth of the multi-quantum well layer is reduced, the uniformity of the In component distribution is increased, and the uniformity of the luminescence wavelength is increased. At the same time, due to the reduction of stress and defects in the multi-quantum well layer, the recombination efficiency of electrons and holes can be increased, and the luminous efficiency of the light-emitting diode can be increased.

Description of the drawings

Figure 1 is a schematic structural diagram of a light-emitting diode epitaxial wafer provided by the present invention;

Figure 2 is a flow chart of a method for preparing a light-emitting diode epitaxial wafer provided by the present invention;

FIG. 3 is a flow chart of step S2 of the method for preparing a light-emitting diode epitaxial wafer provided by the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below.

Unless otherwise stated or contradictory, the terms or phrases used in this article have the following meanings:

In the present invention, "preferred" is only used to describe an embodiment or example with better effect. It should be understood that it does not constitute a limitation on the scope of protection of the present invention.

In the present invention, the technical features described in open terms include closed technical solutions composed of the listed features, and also include open technical solutions including the listed features.

In the present invention, when it comes to a numerical interval, unless otherwise specified, it includes the two endpoints of the numerical interval.

In order to solve the above problems, the present invention provides a light-emitting diode epitaxial wafer, as shown in Figure 1, including a substrate 1, which is sequentially provided with a nucleation layer 2, an intrinsic GaN layer 3, and an N-type semiconductor layer. 4. Wavelength uniformity control layer 5, multiple quantum well layer 6, electron blocking layer 7, and P-type semiconductor layer 8;

The wavelength uniformity control layer 5 includes a compressive stress providing layer 51 and a tensile stress providing layer 52. The compressive stress providing layer 51 includes a first AlN layer 511, an AlGaN layer 512, and a second AlN layer 513 deposited in sequence. The tensile stress providing layer includes a first InGaN layer 521, an InN layer 522, and a second InGaN layer 523 deposited in sequence.

The specific structures of the compressive stress providing layer 51 and the tensile stress providing layer 52 are as follows:

In one embodiment, the thickness of the compressive stress providing layer 51 is 10nm~100nm; the thickness of the exemplary compressive stress providing layer 51 is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, but not Limited to this; the thickness of the first AlN layer 511 or the second AlN layer 513 is 5nm~20nm; the exemplary thickness of the first AlN layer 511 or the second AlN layer 513 is 7nm, 9nm, 11nm, 13nm, 15nm, 17nm, 19nm, but not limited thereto; the thickness of the AlGaN layer 512 is 10nm~80nm; the thickness of the exemplary AlGaN layer 512 is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, but not limited thereto; The Al composition of the AlGaN layer 512 is 0.2~0.7; the exemplary Al composition of the AlGaN layer 512 is 0.3, 0.4, 0.5, and 0.6, but is not limited thereto. In the compressive stress providing layer, since Al atoms are small and AlN and AlGaN materials have small lattice constants, compressive stress can be provided to the epitaxial layer. The compressive stress providing layer is an AlN/AlGaN/AlN sandwich structure. The AlN layer at high temperatures has a high density. However, continuous high-temperature growth of an AlN layer that is too thick will easily cause cracks, so the middle AlGaN material serves as a buffer. The AlN/AlGaN/AlN sandwich structure has a good blocking effect on underlying defects, causing dislocation defects to be distorted and annihilated in this layer, preventing defects from accumulating into the multi-quantum well layer and affecting the uniform distribution of the In component.

In one embodiment, the thickness of the tensile stress providing layer 52 is 10nm~100nm; the thickness of the exemplary tensile stress providing layer 52 is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, but not Limited to this; the thickness of the first InGaN layer 521 or the second InGaN layer 523 is 10nm~50nm; the thickness of the exemplary first InGaN layer 521 or the second InGaN layer 523 is 20nm, 30nm, or 40nm, but is not limited thereto. ; The thickness of the InN layer 522 is 5nm~20nm; Exemplary thicknesses of the InN layer 522 are 7nm, 9nm, 11nm, 13nm, 15nm, 17nm, 19nm, but are not limited thereto; The first InGaN layer 521 Or the In composition of the second InGaN layer 523 is 0.1~0.5; the exemplary In composition of the first InGaN layer 521 or the second InGaN layer 523 is 0.2, 0.3, or 0.4, but is not limited thereto. In the tensile stress providing layer, due to the large In atoms and the large lattice quality of InN and InGaN materials, tensile stress can be provided. The tensile stress providing layer is an InGaN/InN/InGaN sandwich structure, which can not only alleviate the problem of poor stability of InN materials, but also has a small lattice mismatch with the InGaN material of the potential well layer in the multi-quantum well layer, which can reduce the number of multi-quantum wells. The compressive stress on the well layer prevents uneven distribution of In components caused by excessive compressive stress, thereby avoiding aggravation of In segregation.

It should be noted that the compressive stress providing layer and the tensile stress providing layer of the present invention adjust the warpage during the growth of the multi-quantum well layer by setting a specific thickness and Al/In composition. Specifically, if the compressive stress providing layer of the present invention has a large Al component and is thicker, the warpage will be concave when growing to the multi-quantum well layer; the tensile stress providing layer has a large In component and is thicker. , then when the multi-quantum well layer is grown, the warpage becomes convex. The position closest to the multi-quantum well layer is more sensitive to the growth of the multi-quantum well layer, so it is more accurate and has better wavelength uniformity than controlling the warpage of the multi-quantum well layer through the thickness of the nucleation layer.

In summary, the wavelength uniformity control layer proposed by the present invention can adjust the warpage before the growth of the multi-quantum well layer, more accurately control the warpage during the growth of the multi-quantum well layer, and increase the uniformity of the luminescence wavelength. At the same time, the defects of the multi-quantum well layer are reduced, the stress during the growth of the multi-quantum well layer is reduced, the uniformity of the In component distribution is increased, and the uniformity of the luminescence wavelength is increased. At the same time, due to the reduction of stress and defects in the multi-quantum well layer, the recombination efficiency of electrons and holes can be increased, and the luminous efficiency of the light-emitting diode can be increased.

Correspondingly, the present invention provides a method for preparing a light-emitting diode epitaxial wafer, as shown in Figure 2, including the following steps:

S1. Prepare substrate 1;

In one embodiment, a sapphire substrate is used. Preferably, the temperature of the reaction chamber is controlled to be 1000℃~1200℃, the pressure of the reaction chamber is controlled to be 200torr~600torr, the substrate is annealed at a high temperature for 5min~8min in an _H2 atmosphere, and the particles and oxides on the surface of the substrate are cleaned. .

S2. Deposit sequentially on the substrate 1 the nucleation layer 2, the intrinsic GaN layer 3, the N-type semiconductor layer 4, the wavelength uniformity control layer 5, the multiple quantum well layer 6, the electron blocking layer 7, and the P-type semiconductor layer. 8.

As shown in Figure 3, step S2 includes the following steps:

S21. Deposit the nucleation layer 2 on the substrate 1.

In one implementation, the material of the nucleation layer is AlGaN or AlN. This layer is mainly used to provide crystal seeds, alleviate the lattice mismatch between the substrate and the epitaxial layer, and improve the lattice quality of the epitaxial wafer. Preferably, the reaction chamber temperature is controlled to 500°C~700°C, the reaction chamber pressure is 200torr~400torr, N source, Ga source, and Al source are introduced, N ₂ and H ₂ are used as carrier gases, and AlGaN with a thickness of 20nm~40nm is grown. as nucleation layer.

S22. Deposit the intrinsic GaN layer 3 on the nucleation layer 2.

In one embodiment, the temperature of the reaction chamber is controlled at 1100°C to 1150°C, the pressure is controlled at 100torr to 500torr, N source and Ga source are introduced, and an intrinsic GaN layer with a thickness of 300nm to 800nm is grown.

S23. Deposit the N-type semiconductor layer 4 on the intrinsic GaN layer 3.

In one embodiment, the temperature of the reaction chamber is controlled at 1100°C~1150°C, the pressure is controlled at 100torr~500torr, N source, Ga source, and Si source are introduced, and an N-type GaN layer with a thickness of 1 μm~3 μm is grown as N-type semiconductor layer that mainly provides electrons.

S24. Deposit the wavelength uniformity control layer 5 on the N-type semiconductor layer 4.

In one embodiment, the compressive stress providing layer is made by the following method:

Control the temperature of the reaction chamber at 1000℃~1100℃ and the pressure of the reaction chamber at 100torr~500torr. Pass in the Al source and N source to complete the deposition of the first AlN layer. Then feed in the Al source, Ga source and N source to complete. After the deposition of the AlGaN layer, the Al source and the N source are introduced to complete the deposition of the second AlN layer.

In one embodiment, the tensile stress providing layer is made by the following method:

The temperature of the reaction chamber is controlled at 800°C~900°C, and the pressure of the reaction chamber is controlled at 100torr~500torr. The Ga source, In source, and N source are introduced to complete the deposition of the first InGaN layer, and then the In source and N source are introduced. , to complete the deposition of the InN layer, and then pass in the Ga source, In source, and N source to complete the deposition of the second InGaN layer.

It should be noted that the compressive stress providing layer is grown at high temperature. The AlN layer grown at high temperature has a high density. However, continuous high-temperature growth of an AlN layer that is too thick will easily cause cracks, so the intermediate AlGaN material serves as a buffer. The tensile stress providing layer adopts low-temperature growth. The incorporation of the In component requires low-temperature growth. Since InN material has poor stability, the stability can be improved by using an InGaN/InN/InGaN sandwich structure.

S25. Deposit the multi-quantum well layer 6 on the wavelength uniformity control layer 5.

In one embodiment, the multiple quantum well layer is an alternately stacked InGaN quantum well layer and a GaN quantum barrier layer, with a stacking cycle number of 3 to 15; wherein the growth temperature of the InGaN quantum well layer is 700°C to 800°C. The thickness is 2nm~5nm, and the growth pressure is 100torr~500torr; the growth temperature of the GaN quantum barrier layer is 800℃~900℃, the thickness is 5nm~15nm, and the growth pressure is 100torr~500torr.

S26. Deposit the electron blocking layer 7 on the multi-quantum well layer 6.

In one implementation, the electron blocking layer is an alternately stacked InGaN layer and an AlGaN layer. The number of stacking cycles is 3 to 15. The temperature of the reaction chamber is controlled to 900°C to 1000°C, and the pressure of the reaction chamber is controlled to 100torr to 500torr. Input the corresponding material source and grow the electron blocking layer.

S27. Deposit the P-type semiconductor layer 8 on the electron blocking layer 7.

In one embodiment, the temperature of the reaction chamber is controlled at 800°C~1000°C, the pressure is controlled at 100torr~300torr, N source, Ga source, and Mg source are introduced, and a P-type GaN layer with a thickness of 10nm~50nm is grown as The P-type semiconductor layer has a Mg doping concentration of 5×10 ¹⁷ atoms/cm ³ ~1×10 ²⁰ atoms/cm ³ . Too high a Mg doping concentration will destroy the crystal quality, while a low doping concentration will affect the hole concentration.

Correspondingly, the present invention also provides an LED, which includes the above-mentioned light-emitting diode epitaxial wafer. The photoelectric efficiency of the LED is effectively improved, and other electrical properties are good.

The present invention will be further described below with specific examples:

Example 1

This embodiment provides a light-emitting diode epitaxial wafer, including a substrate. The substrate is sequentially provided with a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity control layer, a multi-quantum well layer, and an electron blocking layer. , P-type semiconductor layer;

The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited sequentially. The tensile stress providing layer includes a sequentially deposited The first InGaN layer, the InN layer, and the second InGaN layer.

The thickness of the first AlN layer or the second AlN layer is 10 nm, the thickness of the AlGaN layer is 50 nm, and the Al composition is 0.5.

The thickness of the first InGaN layer or the second InGaN layer is 30 nm, the In composition is 0.3, and the thickness of the InN layer is 10 nm.

Example 2

This embodiment provides a light-emitting diode epitaxial wafer, including a substrate. The substrate is sequentially provided with a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity control layer, a multi-quantum well layer, and an electron blocking layer. , P-type semiconductor layer;

The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited sequentially. The tensile stress providing layer includes a sequentially deposited The first InGaN layer, the InN layer, and the second InGaN layer.

The thickness of the first AlN layer or the second AlN layer is 5 nm, the thickness of the AlGaN layer is 80 nm, and the Al composition is 0.2.

The thickness of the first InGaN layer or the second InGaN layer is 10 nm, the In composition is 0.5, and the thickness of the InN layer is 20 nm.

Example 3

This embodiment provides a light-emitting diode epitaxial wafer, including a substrate. The substrate is sequentially provided with a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity control layer, a multi-quantum well layer, and an electron blocking layer. , P-type semiconductor layer;

The wavelength uniformity control layer includes a compressive stress providing layer and a tensile stress providing layer. The compressive stress providing layer includes a first AlN layer, an AlGaN layer, and a second AlN layer deposited sequentially. The tensile stress providing layer includes a sequentially deposited The first InGaN layer, the InN layer, and the second InGaN layer.

The thickness of the first AlN layer or the second AlN layer is 20 nm, the thickness of the AlGaN layer is 10 nm, and the Al composition is 0.7.

The thickness of the first InGaN layer or the second InGaN layer is 40 nm, the In composition is 0.1, and the thickness of the InN layer is 5 nm.

Comparative example 1

This comparative example provides a light-emitting diode epitaxial wafer. The difference from Embodiment 1 is that there is no wavelength uniformity control layer, and the rest are the same as Embodiment 1.

Comparative example 2

This comparative example provides a light-emitting diode epitaxial wafer. The difference from Embodiment 1 is that the wavelength uniformity control layer does not have a compressive stress providing layer. The rest is the same as Embodiment 1.

Comparative example 3

This comparative example provides a light-emitting diode epitaxial wafer. The difference from Embodiment 1 is that the wavelength uniformity control layer does not have a tensile stress providing layer. The rest is the same as Embodiment 1.

The light-emitting diode epitaxial wafers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were prepared into 10 mil*24 mil chips using the same chip process conditions, and 300 LED chips were extracted respectively. At 120 mA/60 The wavelength uniformity and brightness were tested under mA current. The specific test results are shown in Table 1.

Table 1 Performance test results of LEDs prepared in Examples 1 to 3 and Comparative Examples 1 to 3

It can be seen from the above results that the light-emitting diode epitaxial wafer provided by the present invention has a wavelength uniformity control layer with a specific structure, which can adjust the warpage before the growth of the multi-quantum well layer and more accurately control the warpage during the growth of the multi-quantum well layer. Curved to increase the uniformity of the luminous wavelength. At the same time, the defects of the multi-quantum well layer are reduced, the stress during the growth of the multi-quantum well layer is reduced, the uniformity of the In component distribution is increased, and the uniformity of the luminescence wavelength is increased. At the same time, due to the reduction of stress and defects in the multi-quantum well layer, the recombination efficiency of electrons and holes can be increased, and the luminous efficiency of the light-emitting diode can be increased.

The above is the preferred embodiment of the invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the invention, and these improvements and modifications are also regarded as protection scope of the present invention.

Claims (10)

1. The light-emitting diode epitaxial wafer is characterized by comprising a substrate, wherein a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity regulating layer, a multiple quantum well layer, an electron blocking layer and a P-type semiconductor layer are sequentially arranged on the substrate;

the wavelength uniformity regulating and controlling layer comprises a compressive stress providing layer and a tensile stress providing layer, wherein the compressive stress providing layer comprises a first AlN layer, an AlGaN layer and a second AlN layer which are sequentially deposited, and the tensile stress providing layer comprises a first InGaN layer, an InN layer and a second InGaN layer which are sequentially deposited.

2. The light-emitting diode epitaxial wafer of claim 1, wherein the compressive stress providing layer has a thickness of 10nm to 100nm;

the tensile stress providing layer has a thickness of 10 nm-100 nm.

3. The light-emitting diode epitaxial wafer according to claim 1, wherein the thickness of the first AlN layer or the second AlN layer is 5 nm-20 nm;

the thickness of the AlGaN layer is 10 nm-80 nm.

4. The light-emitting diode epitaxial wafer of claim 1, wherein the Al composition of the AlGaN layer is 0.2 to 0.7.

5. The light emitting diode epitaxial wafer of claim 1, wherein the thickness of the first InGaN layer or the second InGaN layer is 10 nm-50 nm;

the thickness of the InN layer is 5 nm-20 nm.

6. The light-emitting diode epitaxial wafer of claim 1, wherein the In composition of the first InGaN layer or the second InGaN layer is 0.1-0.5.

7. A method for preparing the light-emitting diode epitaxial wafer according to any one of claims 1 to 6, comprising the following steps:

s1, preparing a substrate;

s2, sequentially depositing a nucleation layer, an intrinsic GaN layer, an N-type semiconductor layer, a wavelength uniformity regulating layer, a multiple quantum well layer, an electron blocking layer and a P-type semiconductor layer on the substrate;

the wavelength uniformity regulating and controlling layer comprises a compressive stress providing layer and a tensile stress providing layer, wherein the compressive stress providing layer comprises a first AlN layer, an AlGaN layer and a second AlN layer which are sequentially deposited, and the tensile stress providing layer comprises a first InGaN layer, an InN layer and a second InGaN layer which are sequentially deposited.

8. The method for manufacturing a light-emitting diode epitaxial wafer according to claim 7, wherein the compressive stress providing layer is manufactured by the following method:

controlling the temperature of a reaction chamber at 1000-1100 ℃, controlling the pressure of the reaction chamber at 100-500 torr, introducing an Al source and an N source to finish the deposition of a first AlN layer, introducing the Al source, the Ga source and the N source to finish the deposition of the AlGaN layer, and then introducing the Al source and the N source to finish the deposition of a second AlN layer.

9. The method of manufacturing a light emitting diode epitaxial wafer of claim 7, wherein the tensile stress providing layer is manufactured by:

and controlling the temperature of the reaction chamber at 800-900 ℃, controlling the pressure of the reaction chamber at 100-500 torr, introducing a Ga source, an In source and an N source to finish the deposition of the first InGaN layer, introducing the In source and the N source to finish the deposition of the InN layer, and then introducing the Ga source, the In source and the N source to finish the deposition of the second InGaN layer.

10. An LED, characterized in that the LED comprises a light emitting diode epitaxial wafer according to any one of claims 1 to 6.