High-brightness, low-leakage, high-reliability AlGaInP yellow-green light LED epitaxial wafer

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 an AlGaInP yellow-green LED epitaxial wafer with high brightness, low leakage, and high reliability. Background 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, which are of great significance to the development of modern communication networks in the field of optical communication. These superior performances 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, since 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, resulting in a continuous decrease in device brightness and a significant reduction in reliability. This coupling effect of electron leakage and Mg diffusion creates 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 highly reliable AlGaInP yellow-green LED epitaxial wafer, characterized by comprising the following layer structures sequentially grown on a GaAs substrate:

[0009] An N-type GaAs buffer layer with a thickness of 150-200 nm and a Si doping concentration of 1×10⁻⁶. 18 -2×10 18 atoms / cm 3 The dopant is Si2H6;

[0010] The N-type GaInP etch stop layer has a thickness of 100-200 nm and a Si doping concentration of 1×10⁻⁶. 18 -3×10 18 atoms / cm 3 The dopant is Si2H6;

[0011] An N-type GaAs ohmic contact layer with a thickness of 30-100 nm and a carrier concentration of 3 × 10⁻⁶. 18 -6×10 18 atoms / cm 3 The dopant is Si2H6;

[0012] The N-type AlGaInP current-spreading layer has a thickness of 1000-2500 nm and a composition of (Al... x Ga 1-x ) 0.5 In 0.5 P, 0.6≤x≤1, carrier concentration is 13×10 18 atoms / cm 3 The dopant is Si2H6;

[0013] The N-type electron retarding layer has a multilayer superlattice structure and is composed of Al. y Ga 1-y InP(0.6≤y≤0.8), Al 0.5 In 0.5 P, Al 0.65 In 0.35 The N-type electron retarding layer consists of P-layers, and 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:

[0014] Aly Ga 1-y The maximum thickness of the InP sublayer is 10-20 nm, and the initial thickness is 3-5 nm.

[0015] Al 0.5 In 0.4 The maximum thickness of the P sublayer is 15-25 nm, and the initial thickness is 5-7 nm.

[0016] Al 0.65 In 0.35 The maximum thickness of the P sublayer is 5-10 nm, and the initial thickness is 1-3 nm.

[0017] The total number of layers is 10-25 pairs, and the Si element doping concentration is 1×10⁻⁶. 18 -2×10 18 atoms / cm 3 The dopant is Si2H6;

[0018] An N-type AlInP confinement layer with a thickness of 150-350 nm and a carrier concentration of 7 × 10⁻⁶. 17 -2×10 18 atoms / cm 3 The dopant is Si2H6;

[0019] A multi-quantum-well layer, comprising 30–80 pairs of quantum wells and quantum barriers, wherein:

[0020] Each quantum well is 3-5 nm thick;

[0021] The thickness of the quantum barrier decreases layer by layer from 10-15 nm to 4-6 nm along the growth direction;

[0022] The Al content of the quantum barrier is from Al a Ga 1-a InP (0.6≤a≤0.7) gradually increases to Al b Ga 1-b InP(0.8≤b≤0.9);

[0023] A p-type AlInP confinement layer with a thickness of 250-600 nm is formed. Within this p-type AlInP confinement layer, a Mg diffusion barrier layer with a thickness of 50-150 nm is formed along its thickness direction. The Mg doping concentration of this Mg diffusion barrier layer is 1 × 10⁻⁶ nm. 17 -3×10 17 atoms / cm 3 The carrier concentration in the remaining portion is 8 × 10⁻⁶. 17 -1.5×10 18 atoms / cm 3 The dopant is Cp2Mg;

[0024] P-type GaP current-spreading layers are divided into:

[0025] The bottom layer is a low-Mg-doped layer with a thickness of 200-300 nm and a Mg doping concentration of 3 × 10⁻⁶. 17 -5×10 17 atoms / cm 3 The top layer is highly Mg-doped, with a thickness of 300-1500 nm and a Mg doping concentration of 4-8 × 10⁻⁶. 18 atoms / cm 3 The dopant is Cp2Mg;

[0026] The P-type GaP ohmic contact layer has a thickness of 30-100 nm, a carrier concentration of 0.5-2E20, and is doped with CBr4 or CCl4.

[0027] Preferably, the thickness of the AlGaInP current spreading layer is 1500-2000 nm, and the x ranges from 0.7 to 0.9.

[0028] 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).

[0029] Preferably, the dopant of the N-type electron delay layer is Si₂H₆, and the doping concentration is 1.5 × 10⁻⁶. 18 -2×10 18 atoms / cm 3 .

[0030] 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, and the thickness of the quantum barriers in the multi-quantum well layer gradually decreases from 10 nm to 5 nm. The Al element content in the direction pointing towards the P-type AlInP confinement layer decreases from Al... a Ga 1-a InP (0.65≤a≤0.7) gradually increases to Al b Ga 1-b InP(0.85≤b≤0.9).

[0031] Preferably, the Mg diffusion barrier layer in the P-type AlInP confinement layer has a thickness of 80-120 nm and a doping concentration of 1.5 × 10⁻⁶ nm. 17 -2.5×10 17 atoms / cm 3 If the Mg diffusion barrier layer is too thick or the doping level is too low, it will affect hole injection. If the layer is too thin or the doping level is too high, it will not be able to block Mg.

[0032] Preferably, the Mg diffusion barrier layer is disposed at one-third of the distance 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, thus failing to play its role and causing reliability issues; if it is closer to the quantum well layer, it will lead to insufficient hole injection, affecting the quantum injection efficiency.

[0033] Preferably, the thickness of the lightly doped layer of the P-type GaP current spreading layer is 250-300 nm, and the Mg doping concentration is 4 × 10⁻⁶. 17 -5×10 17 atoms / cm 3 .

[0034] Preferably, the thickness of the highly doped P-type GaP current spreading layer is 500-1000 nm, and the Mg doping concentration is 5 × 10⁻⁶. 18 -7×10 18 atoms / cm 3 .

[0035] Preferably, the thickness of the P-type GaP ohmic contact layer is 50-80 nm, and the dopant is CBr4.

[0036] Through the above technical solutions, the present invention achieves the following beneficial effects:

[0037] Improving electron mobility efficiency and limiting electron leakage: By introducing an N-type electron retarder layer, the electron mobility is significantly reduced through the superlattice structure and the gradient change of Al content, reducing electron leakage to the P-region and improving the recombination efficiency of electrons and holes; through the thickness gradient design, the electron retarder layer further optimizes the electron transport path as the thickness gradually increases, effectively reducing the occurrence of nonradiative recombination.

[0038] 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.

[0039] 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.

[0040] 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 less doped to reduce the probability of Mg diffusion into the light-emitting layer, and the upper layer being more doped to enhance the current spread capability and hole injection efficiency, thereby further improving the light-emitting performance of the device.

[0041] 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.

[0042] 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. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the high-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafer of the present invention.

[0044] Figure 2 This 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.

[0045] Figure 3 This is a schematic diagram of the structure of the P-type AlInP confinement layer in this invention.

[0046] Figure 4 This is a schematic diagram of the structure of the P-type GaP current spreading layer in this invention.

[0047] Figure 5 This is a graph showing the relationship between the forward voltage and forward current of a 14mil yellow-green LED (in this invention embodiment and conventional).

[0048] Figure 6 This is a wavelength-current curve of a 14mil yellow-green LED (in this invention embodiment and conventional).

[0049] Figure 7 This is a graph showing the relationship between the luminous intensity and forward current of a 14mil yellow-green LED (in this invention embodiment and conventional).

[0050] Figure 8 This is a comparison of the ΔLOP of a 14mil yellow-green LED under ambient and high-temperature aging over time (the embodiment of this invention and the conventional method). Detailed Implementation

[0051] 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.

[0052] Example 1

[0053] like Figure 1 As shown, this embodiment provides a high-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafer, the specific structure and parameters of which are as follows:

[0054] N-type GaAs buffer layer L1: 200 nm thick, doped at a concentration of 1.5 × 10⁻⁶. 18 atoms / cm 3 The dopant is Si2H6;

[0055] N-type GaInP etch stop layer L2: 150 nm thick, doping concentration 2 × 10⁻⁶ 18 atoms / cm 3 The dopant is Si2H6;

[0056] N-type GaAs ohmic contact layer L3: 50 nm thick, carrier concentration 4 × 10⁻⁶. 18 atoms / cm 3 The dopant is Si2H6;

[0057] N-type AlGaInP current-spreading layer L4: 2000 nm thick, composition (AlxGa1-x) 0.5 In 0.5 P, where x = 0.7, and the carrier concentration is 2 × 10⁻⁶. 18 atoms / cm 3 ;

[0058] N-type electron retardation layer L5: Employs a multilayer superlattice structure with a total of 20 layers. The thickness of each sublayer increases sequentially along the growth direction. Figure 2 As shown:

[0059] The maximum thickness of the AlyGa1-yInP sublayer is 15nm, and the initial thickness is 4nm;

[0060] Al 0.5 In 0.5 The maximum thickness of the P sublayer is 20 nm, and the initial thickness is 6 nm.

[0061] Al 0.65 In 0.35 The maximum thickness of the P sublayer is 8 nm, and the initial thickness is 2 nm.

[0062] N-type AlInP confinement layer L6: 300 nm thick, doping concentration 1 × 10⁻⁶ 18 atoms / cm 3 ;

[0063] The electron retarding layer utilizes the fact 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 high band gap, which has a stronger restriction on electrons and can effectively reduce electron mobility.

[0064] L7 multi-quantum-well layer: Contains 60 pairs of quantum wells and quantum barriers. Specific parameters:

[0065] The quantum well thickness is 4nm, and the quantum barrier thickness decreases linearly from 12nm to 5nm, which can improve hole injection.

[0066] Al element content from Al a Ga 1-a InP (a = 0.65) gradually increases to Al b Ga 1-b InP (b = 0.85); As the Al content increases, the band gap of the quantum barrier layer gradually increases, which can slow down the migration speed of electrons. Its equivalent efficiency is to move the position of the main emitting layer towards the center of the emitting layer, increase the simultaneous rate of electrons and holes reaching the emitting layer, and increase the probability of radiative recombination.

[0067] P-type AlInP confinement layer L8: 500 nm thick, such as Figure 3 As shown, it includes a lower P-type AlInP barrier layer L71, with a thickness of 50 nm and a doping concentration of 1 × 10⁻⁶ at one-third of the thickness direction. 17 atoms / cm 3 The Mg diffusion barrier layer L72, and the upper P-type AlInP confinement layer L73;

[0068] P-type GaP current-spreading layer L9: such as Figure 4 As shown, it is divided into two parts:

[0069] Bottom low-Mg doped layer L91: 200 nm thick, doping concentration 4 × 10⁻⁶ 17 atoms / cm 3 ;

[0070] Top highly Mg-doped layer L92: 1000 nm thick, doping concentration 6 × 10⁻⁶ 18 atoms / cm 3 ;

[0071] P-type GaP ohmic contact layer L10: 50 nm thick, carrier concentration 1 × 10⁻⁶ 20 atoms / cm 3 The dopant is CBr4.

[0072] Example 2

[0073] Based on Example 1, the following parameters are adjusted:

[0074] N-type electron retarder: The total number of layers has been reduced from 20 pairs to 15 pairs;

[0075] Multiple quantum well layers: The number of quantum well barrier pairs is reduced from 60 pairs to 50 pairs;

[0076] P-type AlInP confinement layer: The thickness of the Mg diffusion barrier layer is adjusted to 100 nm, and the doping concentration is 2 × 10⁻⁶. 17 atoms / cm 3 .

[0077] P-type GaP current spreading layer: The thickness of the low Mg doped layer was changed to 300 nm.

[0078] Example 3

[0079] Based on Example 2, the parameters were further optimized:

[0080] N-type electron retardation layer: employs an 18-pair superlattice structure;

[0081] 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 thickness of the quantum barrier decreases linearly to 4nm;

[0082] P-type GaP current spreading layer: The thickness of the low Mg doped layer was increased to 250 nm.

[0083] Test experiment:

[0084] 1. Device fabrication and testing

[0085] Epitaxial wafers with conventional structures and in Examples 1, 2, and 3 were prepared using metal-organic chemical vapor deposition (MOCVD).

[0086] The light output power and spectral distribution of the device are measured using electroluminescence (EL) spectroscopy.

[0087] The leakage current of a device can be evaluated by measuring its carrier leakage characteristics using IV curves.

[0088] The reliability and brightness degradation of the device under high temperature conditions were evaluated through high-temperature aging tests.

[0089] 2. Experimental results: such as Figures 5-8 As shown, Table 1 contains data when the test current is 60mA.

[0090]

[0091] Parameter description:

[0092] VF(V): Forward Voltage, measured in volts (V).

[0093] WLD (nm): Dominant wavelength, measured in nanometers (nm).

[0094] LOP (mcd): Luminous Output Power, measured in millicandelas (mcd).

[0095] It can be seen that:

[0096] Brightness enhancement effect:

[0097] 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.

[0098] 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.

[0099] Carrier leakage suppression:

[0100] 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.

[0101] High temperature stability:

[0102] After 1000 hours of continuous aging at 75mA current in an environment of 85°C, the brightness decay of Example 1 was only 4%, while that of conventional devices was as high as 17%.

[0103] Examples 2 and 3 showed a brightness attenuation of 3% and 2.5% respectively in this test, demonstrating higher reliability.

[0104] 3. Experimental Conclusions

[0105] Through the above embodiments and experimental data verification, the AlGaInP yellow-green LED epitaxial wafer provided by the present invention has the following advantages:

[0106] Significantly improves the brightness and luminous efficiency of the device;

[0107] Effectively suppresses carrier leakage and non-radiative recombination, reducing leakage current;

[0108] Improve the stability and reliability of devices in high-temperature environments;

[0109] The brightness decay of the device is further slowed down by designing a Mg diffusion barrier layer.

Claims

1. A high-brightness, low-leakage, and highly reliable AlGaInP yellow-green LED epitaxial wafer, characterized in that, This includes the following layer structures grown sequentially on a GaAs substrate: An N-type GaAs buffer layer with a thickness of 150-200 nm and a Si doping concentration of 1 × 10⁻⁶. 18 -2 × 10 18 atoms / cm 3 The dopant is Si2H6; The N-type GaInP etch stop layer has a thickness of 100-200 nm and a Si doping concentration of 1 × 10⁻⁶. 18 -3 × 10 18 atoms / cm 3 The dopant is Si2H6; The N-type GaAs ohmic contact layer has a thickness of 30-100 nm and a carrier concentration of 3 × 10⁻⁶. 18 -6 × 10 18 atoms / cm 3 The dopant is Si2H6; The N-type AlGaInP current-spreading layer has a thickness of 1000-2500 nm and a composition of (Al... x Ga 1-x ) 0.5 In 0.5 P, where 0.6 ≤ x ≤ 1, and the carrier concentration is 1 × 10⁻⁶. 18 -3 × 10 18 atoms / cm 3 The dopant is Si2H6; The N-type electron retarding layer has a multilayer superlattice structure and is composed of Al. y Ga 1-y InP, Al 0.5 In 0.5 P, Al 0.65 In 0.35 The N-type electron retarding layer consists of P sublayers, where 0.6 ≤ y ≤ 0.

8. The thickness of each sublayer in the N-type electron retarding layer 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: Al y Ga 1-y The maximum thickness of the InP sublayer is 10-20 nm, and the initial thickness is 3-5 nm. Al 0.5 In 0.5 The maximum thickness of the P sublayer is 15-25 nm, and the initial thickness is 5-7 nm; Al 0.65 In 0.35 The maximum thickness of the P sublayer is 5-10 nm, and the initial thickness is 1-3 nm; The total number of layers is 10-25 pairs, and the Si element doping concentration is 1 × 10⁻⁶. 18 -2 × 10 18 atoms / cm 3 The dopant is Si2H6; The N-type AlInP confinement layer has a thickness of 150-350 nm and a carrier concentration of 7 × 10⁻⁶. 17 -2 × 10 18 atoms / cm 3 The dopant is Si2H6; A multi-quantum-well layer contains 30-80 pairs of quantum wells and quantum barriers, each pair consisting of one quantum well and one quantum barrier, 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 is from Al a Ga 1-a InP gradually increases to Al b Ga 1-b InP, where 0.6≤a≤0.7, 0.8≤b≤0.9; A p-type AlInP confinement layer with a thickness of 250-600 nm is formed. Within this p-type AlInP confinement layer, a Mg diffusion barrier layer with a thickness of 50-150 nm is formed along its thickness direction. The Mg diffusion barrier layer has a doping concentration of 1 × 10⁻⁶. 17 -3 × 10 17 atoms / cm 3 The carrier concentration in the remaining portion is 8 × 10⁻⁶. 17 -1.5 × 10 18 atoms / cm 3 The dopant is Cp2Mg; P-type GaP current-spreading layers are divided into: The bottom layer has a low Mg doping concentration of 200-300 nm, with a Mg doping concentration of 3 × 10⁻⁶. 17 -5 × 10 17 atoms / cm 3 The top layer is highly Mg-doped, with a thickness of 300-1500 nm and a Mg doping concentration of 4 × 10⁻⁶. 18 -8 × 10 18 atoms / cm 3 The dopant is Cp2Mg; The p-type GaP ohmic contact layer has a thickness of 30-100 nm and a carrier concentration of 0.5 × 10⁻⁶. 20 -2× 10 20 atoms / cm 3 The dopant is CBr4 or CCl4.

2. The AlGaInP yellow-green LED epitaxial wafer according to claim 1, characterized in that, 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).

3. The AlGaInP yellow-green LED epitaxial wafer according to claim 1, characterized in that, The dopant for the N-type electron delay layer is Si₂H₆, with a doping concentration of 1.5 × 10⁻⁶. 18 -2 × 10 18 atoms / cm 3 .

4. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, 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, and the thickness of the quantum barriers in the multi-quantum well layer gradually decreases from 10 nm to 5 nm. The Al content in the direction from the quantum well layer to the P-type AlInP confinement layer decreases from Al... a Ga 1-a InP gradually increases to Al b Ga 1-b InP, where 0.65≤a≤0.7 and 0.85≤b≤0.

9.

5. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, The Mg diffusion barrier layer in the p-type AlInP confinement layer has a thickness of 80-120 nm and a doping concentration of 1.5 × 10⁻⁶. 17 -2.5 × 10 17 atoms / cm 3 .

6. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, 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 according to any one of claims 1, characterized in that, The thinnest doped layer of the p-type GaP current-spreading layer is 250-300 nm thick, and the Mg doping concentration is 4 × 10⁻⁶. 17 -5 × 10 17 atoms / cm 3 .

8. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, The highly doped layer of the p-type GaP current-spreading layer has a thickness of 500-1000 nm and a Mg doping concentration of 5 × 10⁻⁶. 18 -7 × 10 18 atoms / cm 3 .

9. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, The thickness of the p-type GaP ohmic contact layer is 50-80 nm, and the dopant is CBr4.

10. The AlGaInP yellow-green LED epitaxial wafer according to any one of claims 1, characterized in that, The thickness of the N-type AlGaInP current spreading layer is 1500-2000 nm, and x ranges from 0.7 to 0.9.

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