High-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafers

Abstract

This invention discloses a high-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafer. The epitaxial wafer comprises, sequentially grown on a GaAs substrate, an N-type GaAs buffer layer, an N-type GaInP etch stop layer, an N-type GaAs ohmic contact layer, an N-type AlGaInP current spreading layer, an N-type electron delay layer, an N-type AlInP confinement layer, a multi-quantum well layer, a P-type AlInP confinement layer, a P-type GaP current spreading layer, and a P-type GaP ohmic contact layer. By introducing the electron delay layer, a quantum barrier thickness gradient design, and a Mg diffusion blocking layer, electron leakage and Mg diffusion are effectively suppressed, non-radiative recombination is reduced, and the luminous efficiency and high-temperature operating stability of the LED are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of LED technology, specifically to a high-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafer. Prior Technology

[0002] AlGaInP yellow-green LED chips offer efficient, energy-saving, and environmentally friendly lighting solutions for home, commercial, and public lighting. Furthermore, they can be used to manufacture high-resolution, high-color-fidelity displays, enhancing the realism and detail of the visual experience. Simultaneously, yellow-green LED chips possess high-speed, high-efficiency data transmission capabilities, playing a crucial role in the development of modern communication networks in the field of optical communication. These superior performance characteristics rely on the unique advantages of the AlGaInP material system and its complex epitaxial structure design; the rationality of the epitaxial structure directly affects the chip's performance and application range.

[0003] Existing quaternary AlGaInP short-wavelength LED epitaxial structures typically include: a GaAs substrate, followed by sequentially grown N-type GaAs buffer layer, N-type GaInP etch stop layer, N-type GaAs ohmic contact layer, N-type AlGaInP current spreading layer, N-type AlInP confinement layer, multiple quantum well layer, P-type AlInP confinement layer, P-type GaP current spreading layer, and P-type GaP ohmic contact layer. This structure exhibits good luminous efficiency and high reliability in practical applications. However, in the development towards shorter wavelengths, the material system faces many challenges, especially the significant impact of Al content variations on device performance.

[0004] As the Al content in the multi-quantum-well layer increases, the AlGaInP material gradually transitions from a direct bandgap to an indirect bandgap, requiring phonon participation in the luminescence process. This significantly reduces the quantum efficiency of recombination luminescence and decreases the probability of electron-hole recombination. Furthermore, because electrons migrate much faster than holes, a large number of electrons easily leak into the P-region under non-equilibrium conditions, increasing nonradiative recombination. This not only leads to a decrease in luminescence efficiency but also causes a large amount of heat to accumulate in the interface layer region, narrowing the semiconductor's bandgap and further exacerbating electron leakage.

[0005] On the other hand, under high-temperature operating conditions, Mg elements in P-type doping easily diffuse into the quantum well region, forming impurity energy levels, trapping electrons, and further increasing non-radiative recombination, leading to a continuous decrease in the luminous efficiency of the quantum well. Furthermore, as the device's operating time increases, this effect gradually accumulates, causing a continuous decline in device brightness and a significant reduction in reliability. This coupling effect of electron leakage and Mg diffusion forms a vicious cycle, severely restricting the performance improvement and stability of short-wavelength AlGaInP LED devices. Summary of the Invention

[0006] To address the above problems, this invention provides an improved high-brightness yellow-green wavelength quaternary AlGaInP epitaxial wafer.

[0007] The specific technical solution of the present invention is as follows:

[0008] A high-brightness, low-leakage, and high-reliability AlGaInP yellow-green LED epitaxial wafer, comprising the following layers sequentially grown on a GaAs substrate: An N-type GaAs buffer layer with a thickness of 150-200 nm, a Si doping concentration of 1 × 10¹⁸ - 2 × 10¹⁸ atoms / cm³, and Si₂H₆ as the dopant; The N-type GaInP etch stop layer has a thickness of 100-200 nm, a Si doping concentration of 1 × 10¹⁸ - 3 × 10¹⁸ atoms / cm³, and the dopant is Si₂H₆. The N-type GaAs ohmic contact layer has a thickness of 30-100 nm, a carrier concentration of 3 × 10¹⁸ - 6 × 10¹⁸ atoms / cm³, and is doped with Si₂H₆. The N-type AlGaInP current-spreading layer has a thickness of 1000-2500 nm, a composition of (AlxGa1-x)0.5In0.5P, where 0.6≤x≤1, a carrier concentration of 13 × 10¹⁸ atoms / cm³, and is doped with Si₂H₆. The N-type electron retarding layer has a multilayer superlattice structure, consisting of sublayers of AlyGa1-yInP (0.6≤y≤0.8), Al₀.₅In₀.₅P, and Al₀.₆₅In₀.₃₅P. In this N-type electron retarding layer, the thickness of each sublayer increases progressively along the epitaxial growth direction, specifically determined by the following formula: Thickness of the nth layer = Initial thickness + (Maximum thickness / Total number of layers) × (n-1), where: The maximum thickness of the AlyGa1-yInP sublayer is 10-20 nm, and the initial thickness is 3-5 nm; The maximum thickness of the Al₀.₅In₀.₅P sublayer is 15-25 nm, with an initial thickness of 5-7 nm; The maximum thickness of the Al₀.₆₅In₀.₃₅P sublayer is 5-10 nm, and the initial thickness is 1-3 nm; The total number of layers is 10-25 pairs, the Si element doping concentration is 1 × 10¹⁸ - 2 × 10¹⁸ atoms / cm³, and the dopant is Si₂H₆; The N-type AlInP confinement layer has a thickness of 150-350 nm, a carrier concentration of 7 × 10¹⁷ - 2 × 10¹⁸ atoms / cm³, and is doped with Si₂H₆. Multiple quantum well layers, containing 30-80 pairs of quantum wells and quantum barriers, wherein: Each quantum well is 3-5 nm thick; The thickness of the quantum barrier decreases layer by layer from 10-15 nm to 4-6 nm along the growth direction; The Al content of the quantum barrier gradually increases from AlaGa1-aInP (0.6≤a≤0.7) to AlbGa1-bInP (0.8≤b≤0.9);

[0009] A p-type AlInP confinement layer with a thickness of 250-600 nm is formed. Within this layer, a Mg diffusion barrier layer with a thickness of 50-150 nm is placed along its thickness direction. The Mg doping concentration is 1 × 10¹⁷ - 3 × 10¹⁷ atoms / cm³, and the remaining portion has a carrier concentration of 8 × 10¹⁷ - 1.5 × 10¹⁸ atoms / cm³. The dopant is Cp₂Mg. P-type GaP current-spreading layers are divided into: The bottom layer has a low Mg doping layer with a thickness of 200-300 nm and a Mg doping concentration of 3 × 10¹⁷-5 × 10¹⁷ atoms / cm³, while the top layer has a high Mg doping layer with a thickness of 300-1500 nm and a Mg doping concentration of 4-8 × 10¹⁸ atoms / cm³. The dopant is Cp₂Mg. A p-type GaP ohmic contact layer with a thickness of 30-100 nm and a carrier concentration of [missing information]. [0.5-2E20], the dopant is CBr₄ or CCl₄.

[0010] Preferably, the thickness of the AlGaInP current spreading layer is 1500-2000 nm, and the x ranges from 0.7 to 0.9.

[0011] Preferably, the total number of N-type electron delay layers is 15-20 pairs, and the thickness of each sub-layer is designed according to the formula: thickness of the nth layer = initial thickness + maximum thickness / total number of layers × (n-1).

[0012] Preferably, the dopant of the N-type electron delay layer is Si₂H₆, and the doping concentration is 1.5 × 10¹⁸ - 2 × 10¹⁸ atoms / cm³.

[0013] Preferably, the number of quantum wells and quantum barriers in the multi-quantum well layer is 40-60 pairs, the thickness of the quantum wells in the multi-quantum well layer is 4-5 nm, the thickness of the quantum barriers in the multi-quantum well layer gradually decreases from 10 nm to 5 nm, and the Al content in the direction pointing to the P-type AlInP confinement layer gradually increases from AlaGa1-aInP (0.65≤a≤0.7) to AlbGa1-bInP (0.85≤b≤0.9).

[0014] Preferably, the thickness of the Mg diffusion barrier layer in the P-type AlInP confinement layer is 80-120 nm, and the doping concentration is 1.5 × 10¹⁷-2.5 × 10¹⁷ atoms / cm³. If the Mg diffusion barrier layer is too thick or the doping is too low, it will affect hole injection. If the thickness is too thin or the doping is too high, it will not be able to block Mg.

[0015] Preferably, the Mg diffusion barrier layer is located one-third of the way from the side of the P-type AlInP confinement layer closest to the multi-quantum-well layer. With the adjustment of the thickness and doping concentration of the Mg diffusion barrier layer, if it is far from the quantum well and close to the P-type GaP current extension layer, the Mg will diffuse too much and will bypass the barrier layer, resulting in reliability issues. If it is closer to the quantum well layer, it will lead to insufficient hole injection, affecting the quantum injection efficiency.

[0016] Preferably, the thickness of the low-doped layer of the P-type GaP current spreading layer is 250-300 nm, and the Mg doping concentration is 4 × 10¹⁷-5 × 10¹⁷ atoms / cm³.

[0017] Preferably, the thickness of the highly doped layer of the P-type GaP current spreading layer is 500-1000 nm, and the Mg element doping concentration is 5 × 10¹⁸-7 × 10¹⁸ atoms / cm³.

[0018] Preferably, the thickness of the P-type GaP ohmic contact layer is 50-80 nm, and the dopant is CBr₄.

[0019] Through the above technical solutions, the present invention achieves the following beneficial effects:

[0020] Improving electron mobility efficiency and limiting electron leakage: An N-type electron retarder layer is introduced. Through the superlattice structure and the gradient change of Al content, the electron mobility is significantly reduced, the leakage of electrons to the P-region is reduced, and the recombination efficiency of electrons and holes is improved. Through the thickness gradient design, the electron transport path is further optimized as the electron retarder layer gradually increases in thickness, effectively reducing the occurrence of nonradiative recombination.

[0021] Optimizing the luminescence efficiency of the multi-quantum-well layer: The thickness of the quantum barrier layer is gradually reduced from 10-15 nm to 4-6 nm, effectively improving the hole injection efficiency. Simultaneously, by gradually increasing the Al content in the quantum barrier layer, the bandgap is gradually increased, optimizing the efficiency of synchronous arrival of electrons and holes at the luminescent layer, thereby increasing the probability of radiative recombination. The purpose of this design is to adjust the position of the main luminescent layer to the center of the quantum well layer, thereby improving luminescence efficiency.

[0022] Suppressing Mg diffusion and improving device stability: A lightly doped Mg diffusion barrier layer is set in the P-type AlInP layer. The barrier effect effectively reduces the amount of Mg diffusing into the light-emitting layer, thereby reducing non-radiative recombination caused by Mg impurity energy levels. The thickness and doping concentration of the barrier layer are precisely designed to balance suppressing Mg diffusion and maintaining hole injection efficiency.

[0023] Improved performance of P-type GaP current spread layer: The P-type GaP current spread layer is designed as two parts, with the lower layer being low-doped to reduce the probability of Mg diffusion into the light-emitting layer, and the upper layer being high-doped to enhance the current spread capability and hole injection efficiency, thereby further improving the light-emitting performance of the device.

[0024] Significantly improves device brightness and reliability: Multiple innovative designs work together to significantly increase the recombination probability of electrons and holes, reduce carrier leakage and nonradiative recombination, and greatly improve the brightness and reliability of AlGaInP short-wavelength LEDs, especially showing greater stability under high-temperature conditions.

[0025] In summary, this invention solves the problems of brightness decay and insufficient device reliability in the prior art, giving the AlGaInP yellow-green LED chip of this invention significant advantages in terms of luminous efficiency and stability. Simple Explanation of the Diagram

[0026] Figure 1 is a schematic diagram of the structure of the AlGaInP yellow-green LED epitaxial wafer of the present invention, which features high brightness, low leakage, and high reliability. Figure 2 is a graph showing the relationship between the thickness of each sublayer of the N-type electron delay layer in Embodiment 1 of the present invention and the gradual linear increase of the number of layers. Figure 3 is a schematic diagram of the structure of the P-type AlInP confinement layer in this invention. Figure 4 is a schematic diagram of the structure of the P-type GaP current spreading layer in this invention. Figure 5 shows the relationship between the forward voltage and forward current of a 14mil yellow-green LED (in this embodiment and in the conventional). Figure 6 is a wavelength-current curve of a 14mil yellow-green LED (in this invention embodiment and conventional). Figure 7 shows the relationship between the luminous intensity of a 14mil yellow-green LED and the forward current (in this invention embodiment and conventional). Figure 8 shows a comparison of the ΔLOP of a 14mil yellow-green LED at room temperature and high temperature over time (the embodiment of this invention and the conventional method). Implementation

[0027] The preferred embodiments of the present invention are given below with reference to the accompanying drawings to illustrate the technical solution of the present invention in detail.

[0028] Example 1

[0029] As shown in Figure 1, this embodiment provides a high-brightness, low-leakage, and high-reliability AlGaInP yellow-green LED epitaxial wafer, the specific structure and parameters of which are as follows: N-type GaAs buffer layer L1: 200 nm thick, doped at 1.5 × 10¹⁸ atoms / cm³, with Si₂H₆ as the dopant; N-type GaInP etch stop layer L2: thickness 150 nm, doping concentration 2 × 10¹⁸ atoms / cm³, dopant Si₂H₆; The N-type GaAs ohmic contact layer L3 has a thickness of 50 nm, a carrier concentration of 4 × 10¹⁸ atoms / cm³, and is doped with Si₂H₆. The N-type AlGaInP current-spreading layer L4 has a thickness of 2000 nm and a composition of (AlxGa1-x)₀.₅In₀.₅P, where x = 0.7, and a carrier concentration of 2 × 10¹⁸ atoms / cm³. N-type electron retarder L5: It adopts a multilayer superlattice structure with a total of 20 pairs of layers. The thickness of each sublayer increases sequentially along the growth direction, as shown in Figure 2. The maximum thickness of the AlyGa1-yInP sublayer is 15 nm, and the initial thickness is 4 nm; The maximum thickness of the Al₀.₅In₀.₅P sublayer is 20 nm, and the initial thickness is 6 nm. The maximum thickness of the Al₀.₆₅In₀.₃₅P sublayer is 8 nm, and the initial thickness is 2 nm; N-type AlInP confinement layer L6: 300 nm thick, doping concentration of 1 × 10¹⁸ atoms / cm³; The electron retarding layer utilizes the principle that the electron mobility of AlGaInP changes with the Al content; the higher the Al content, the lower the mobility. In particular, the last layer in the three groups has a high Al content and a wide bandgap, which more strongly restricts electrons and can effectively reduce electron mobility. L7 multi-quantum-well layer: contains 60 pairs of quantum wells and quantum barriers, specific parameters: The quantum well thickness is 4 nm, and the quantum barrier thickness decreases linearly from 12 nm to 5 nm, which can improve hole injection; The Al content gradually increases from AlaGa1-aInP (a = 0.65) to AlbGa1-bInP (b = 0.85). As the Al content increases, the band gap of the quantum barrier layer gradually increases, which can slow down the electron migration speed. Its equivalent efficiency is to move the position of the main emitting layer towards the center of the emitting layer, increase the simultaneity of electrons and holes reaching the emitting layer, and increase the probability of radiative recombination. P-type AlInP confinement layer L8: The thickness is 500 nm, as shown in Figure 3. It includes a lower P-type AlInP barrier layer L71, a Mg diffusion barrier layer L72 with a thickness of 50 nm and a doping concentration of 1 × 10¹⁷ atoms / cm³ at one-third of the thickness direction, and an upper P-type AlInP confinement layer L73. The P-type GaP current-spreading layer L9, as shown in Figure 4, is divided into two parts: Bottom low-Mg doped layer L81: 200 nm thick, doping concentration 4 × 10¹⁷ atoms / cm³; The top highly Mg-doped layer L82 has a thickness of 1000 nm and a doping concentration of 6 × 10¹⁸ atoms / cm³. P-type GaP ohmic contact layer L10: thickness is 50 nm, carrier concentration is 1 × 10²⁰ atoms / cm³, and dopant is CBr₄.

[0030] Example 2

[0031] Based on Example 1, the following parameters are adjusted: N-type electron retarder: The total number of layers has been reduced from 20 pairs to 15 pairs; Multiple quantum well layers: The number of quantum well barrier pairs is reduced from 60 pairs to 50 pairs; P-type AlInP confinement layer: The thickness of the Mg diffusion barrier layer is adjusted to 100 nm, and the doping concentration is 2 × 10¹⁷ atoms / cm³. P-type GaP current spreading layer: The thickness of the low Mg doped layer was increased to 300 nm.

[0032] Example 3 Based on Example 2, the parameters were further optimized: N-type electron retarder: employs an 18-pair superlattice structure; Multiple quantum well layers: the Al content of the quantum barrier gradually increases from AlaGa1-aInP (a = 0.7) to AlbGa1-bInP (b = 0.9); the quantum barrier thickness decreases linearly to 4 nm; P-type GaP current spreading layer: The thickness of the low Mg doped layer was increased to 250 nm.

[0033] Test Experiment:

[0034] 1. Device fabrication and testing

[0035] Epitaxial wafers with conventional structures and those in Examples 1, 2, and 3 were prepared using metal-organic chemical vapor deposition (MOCVD).

[0036] The light output power and spectral distribution of the device are measured using electroluminescence (EL) spectroscopy.

[0037] The leakage current of a device can be evaluated by measuring its carrier leakage characteristics using IV curves.

[0038] The reliability and brightness degradation of the device under high temperature conditions were evaluated through high-temperature aging tests.

[0039] 2. Experimental results: As shown in Figures 5-8, Table 1 shows the data when the test current is 60mA. wafer size 14mil*14mil sample VF (V) WLD (nm) LOP (mcd) Example 1 2.24 568.7 1980 Example 2 2.24 567.9 2031 Example 3 2.26 568.2 2067 Tradition 2.21 568.5 1720

[0040] Parameter description:

[0041] VF (V): Forward Voltage, measured in volts (V).

[0042] WLD (nm): Dominant wavelength, measured in nanometers (nm).

[0043] LOP (mcd): Luminous Output Power, measured in millicandelas (mcd).

[0044] It can be seen that:

[0045] Brightness enhancement effect:

[0046] The optical output power of the device in Example 1 is increased by about 15% compared with the conventional structure, and it maintains stable output at 60°C.

[0047] Examples 2 and 3 further optimized the Al content and Mg diffusion inhibition effect, resulting in a 18% and 20% increase in brightness compared to the traditional structure, respectively.

[0048] Carrier leakage suppression:

[0049] Experiments show that the N-type electron delay layer effectively suppresses electron leakage. Under the same MQW logarithm, the saturation current of Example 1 is 10mA higher than that of the conventional structure.

[0050] High temperature stability:

[0051] After 1000 hours of continuous aging at 75mA in an 85°C environment, the brightness decay of Example 1 was only 4%, while that of conventional devices was as high as 17%.

[0052] Examples 2 and 3 showed a brightness attenuation of 3% and 2.5% respectively in this test, demonstrating higher reliability.

[0053] 3. Experimental Conclusions

[0054] Based on the above embodiments and experimental data, the AlGaInP yellow-green LED epitaxial wafer provided by this invention has the following advantages: Significantly improves the brightness and luminous efficiency of the device; Effectively suppresses carrier leakage and non-radiative recombination, reducing leakage current; Improve the stability and reliability of devices in high-temperature environments; The brightness decay of the device is further slowed down by designing a Mg diffusion barrier layer.

[0055] L1: N-type GaAs buffer layer L2: N-type GaInP corrosion stop layer L3: N-type GaAs ohmic contact layer L4: N-type AlGaInP current spreading layer L5: N-type electron retarder layer L6: N-type AlInP confinement layer L7: Multiple quantum well layers L8: P-type AlInP confinement layer L9: P-type GaP current spreading layer L10: P-type GaP ohmic contact layer L71: Lower P-type AlInP confinement layer L72: Mg diffusion barrier layer L73: Upper P-type AlInP confinement layer L81: Bottom low-Mg doped layer L82: Top high Mg doped layer

Claims

1. A high-brightness, low-leakage, and high-reliability AlGaInP yellow-green LED epitaxial wafer, comprising the following layers sequentially grown on a GaAs substrate: an N-type GaAs buffer layer with a thickness of 150-200 nm, a Si doping concentration of 1 × 10¹⁸-2 × 10¹⁸ atoms / cm³, and Si₂H₆ as the dopant; an N-type GaInP etch stop layer with a thickness of 100-200 nm, a Si doping concentration of 1 × 10¹⁸-3 × 10¹⁸ atoms / cm³, and Si₂H₆ as the dopant; an N-type GaAs ohmic contact layer with a thickness of 30-100 nm, a carrier concentration of 3 × 10¹⁸-6 × 10¹⁸ atoms / cm³, and Si₂H₆ as the dopant; and an N-type AlGaInP current spreading layer with a thickness of 1000-2500 nm. nm, composition is (AlxGa1-x)0.5In0.5P, where 0.6≤x≤1, carrier concentration is 1 × 10¹⁸ - 3 × 10¹⁸ atoms / cm³, dopant is Si₂H₆; N-type electron retardation layer, with multilayer superlattice structure, is composed of (AlyGa1-y)0.5In0.5P (0.6≤y≤0.8), Al₀.₅In₀.₅P, and Al₀.₆₅In₀.₃₅P sublayers. In the N-type electron retardation layer, the thickness of each sublayer increases layer by layer along the epitaxial growth direction, specifically determined according to the following formula: thickness of the nth layer = initial thickness + [(maximum thickness - initial thickness) / (total number of layers - 1)] × (n-1), where: The maximum thickness of the (AlyGa1-y)0.5In0.5P sublayer is 10-20 nm, with an initial thickness of 3-5 nm; the maximum thickness of the Al₀.₅In₀.₅P sublayer is 15-25 nm, with an initial thickness of 5-7 nm; the maximum thickness of the Al₀.₆₅In₀.₃₅P sublayer is 5-10 nm, with an initial thickness of 1-3 nm; the total number of layers is 10-25 pairs, the Si doping concentration is 1 × 10¹⁸ - 2 × 10¹⁸ atoms / cm³, and the dopant is Si₂H₆; the N-type AlInP confinement layer has a thickness of 150-350 nm, a carrier concentration of 7 × 10¹⁷ - 2 × 10¹⁸ atoms / cm³, and the dopant is Si₂H₆; A multi-quantum-well layer, comprising 30-80 pairs of quantum wells and quantum barriers, each pair consisting of one quantum well and one quantum barrier, wherein: each quantum well has a thickness of 3-5 nm; the thickness of the quantum barriers decreases layer by layer from 10-15 nm to 4-6 nm along the growth direction; the Al content of the quantum barriers gradually increases from (AlaGa1-a)0.5In0.5P (0.6≤a≤0.7) to (AlbGa1-b)0.5In0.5P (0.8≤b≤0.9); a p-type AlInP confinement layer with a thickness of 250-600 nm, wherein a Mg diffusion barrier layer with a thickness of 50-150 nm is disposed along its thickness direction, the Mg diffusion barrier layer having a doping concentration of 1 × 10¹⁷-3 × 10¹⁷ atoms / cm³, and the carrier concentration of the remaining portion being 8 × 10¹⁷-1.5 × 10¹⁸ atoms / cm³, doped with Cp₂Mg; P-type GaP current spreading layer, divided into: bottom low Mg doped layer, thickness 200-300 nm, Mg doping concentration 3 × 10¹⁷-5 × 10¹⁷ atoms / cm³, top high Mg doped layer, thickness 300-1500 nm, Mg doping concentration 4 × 10¹⁸-8 × 10¹⁸ atoms / cm³, doped with Cp₂Mg; P-type GaP ohmic contact layer, thickness 30-100 nm, carrier concentration 0.5 ×10²⁰-2 × 10²⁰ atoms / cm³, doped with CBr₄ or CCl₄.

2. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The total number of N-type electron delay layers is 15-20 pairs, and the thickness of each sub-layer is designed according to the formula: thickness of the nth layer = initial thickness + [(maximum thickness - initial thickness) / (total number of layers - 1)] × (n-1).

3. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The dopant of the N-type electron delay layer is Si₂H₆, and the doping concentration is 1.5 × 10¹⁸ - 2 × 10¹⁸ atoms / cm³.

4. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The number of quantum wells and quantum barriers in the multi-quantum well layer is 40 to 60 pairs, the thickness of the quantum wells in the multi-quantum well layer is 4 nm to 5 nm, the thickness of the quantum barriers in the multi-quantum well layer gradually decreases from 10 nm to 5 nm, and the Al content in the direction from the quantum well layer to the P-type AlInP confinement layer gradually increases from (AlaGa1-a)0.5In0.5P (0.65≤a≤0.7) to (AlbGa1-b)0.5In0.5P (0.85≤b≤0.9).

5. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The thickness of the Mg diffusion barrier layer in the P-type AlInP confinement layer is 80-120 nm, and the doping concentration is 1.5 × 10¹⁷-2.5 × 10¹⁷ atoms / cm³.

6. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The Mg diffusion barrier layer is positioned one-third of the way from the side of the P-type AlInP confinement layer closest to the multi-quantum-well layer.

7. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The thickness of the low-doped layer of the P-type GaP current extension layer is 250-300 nm, and the Mg doping concentration is 4 × 10¹⁷-5 × 10¹⁷ atoms / cm³.

8. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The thickness of the highly doped P-type GaP current extension layer is 500 nm to 1000 nm, and the Mg doping concentration is 5 × 10¹⁸ - 7 × 10¹⁸ atoms / cm³.

9. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The thickness of the P-type GaP ohmic contact layer is 50 to 80 nm, and the dopant is CBr₄.

10. The AlGaInP yellow-green LED epitaxial wafer as described in claim 1, wherein, The thickness of the N-type AlGaInP current-spreading layer is 1500 to 2000 nm, and x ranges from 0.7 to 0.9.

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