LED chip and white light LED light source

Abstract

The invention relates to the technical field of semiconductors, and particularly discloses an LED chip and a white light LED light source, the LED chip comprises a substrate and an epitaxial layer arranged on the substrate, and the epitaxial layer comprises a light emitting layer. The light-emitting layer comprises a first wavelength multi-quantum well layer, a second wavelength multi-quantum well layer, a third wavelength multi-quantum well layer and a fourth wavelength multi-quantum well layer which are sequentially stacked in the epitaxial direction; wherein lambda1 > lambda2 > lambda3 = lambda4, 460 nm < = lambda1 < = 480 nm, 445 nm < = lambda2 < = 460 nm, and 430 nm < = lambda3 = lambda4 < = 445 nm; each multi-quantum well layer is of a periodic structure formed by alternately stacking well layers and barrier layers, the barrier layer of the first wavelength multi-quantum well layer and the barrier layer of the second wavelength multi-quantum well layer are doped with Si, the barrier layer of the fourth wavelength multi-quantum well layer is doped with Mg, and the barrier layer of the third wavelength multi-quantum well layer is a material layer which is not intentionally doped with Mg and Si. The LED chip serves as an excitation light source for exciting the red and green mixed fluorescent powder layer, the color rendering index of the output full-spectrum white light LED light source is higher, and meanwhile higher luminous efficiency is achieved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to an LED chip and a white LED light source. Background Art

[0002] Currently, the mainstream technical path of full-spectrum white LEDs is to use a blue LED chip to excite a red and green mixed phosphor layer (including a red phosphor and a green phosphor), thereby achieving the output of full-spectrum white light. Among them, the blue LED chip mainly uses a blue chip that emits a single high-energy short-wave blue light (generally around 450 nm). In the spectral curve of such a full-spectrum white LED light source, the spectral curve of the blue light band fluctuates greatly, with poor stability. It is difficult for the phosphor to be stably and fully excited by the blue light energy, affecting the color rendering index and luminous efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide an LED chip and a white LED light source in view of the existing technical status. The LED chip of the present invention is used as an excitation light source for exciting a red and green mixed phosphor layer, and the output full-spectrum white LED light source has a higher color rendering index and higher luminous efficiency at the same time.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] First, the present invention provides an LED chip, including a substrate and an epitaxial layer disposed on the substrate. The epitaxial layer includes a buffer layer, an N-type layer, a low-temperature stress release layer, a light-emitting layer, an electron blocking layer, and a P-type layer sequentially disposed along the epitaxial direction;

[0006] The light-emitting layer includes a first-wavelength multiple quantum well layer, a second-wavelength multiple quantum well layer, a third-wavelength multiple quantum well layer, and a fourth-wavelength multiple quantum well layer sequentially stacked along the epitaxial direction;

[0007] The emission wavelength of the first-wavelength multiple quantum well layer is λ1, the emission wavelength of the second-wavelength multiple quantum well layer is λ2, the emission wavelength of the third-wavelength multiple quantum well layer is λ3, and the emission wavelength of the fourth-wavelength multiple quantum well layer is λ4. Among them, λ1 > λ2 > λ3 = λ4, and 460 nm ≤ λ1 ≤ 480 nm, 445 nm ≤ λ2 ≤ 460 nm, 430 nm ≤ λ3 = λ4 ≤ 445 nm;

[0008] Each multiple quantum well layer is a periodic structure formed by alternating well layers and barrier layers. The barrier layers of the first-wavelength multiple quantum well layer and the second-wavelength multiple quantum well layer are doped with Si, the barrier layer of the fourth-wavelength multiple quantum well layer is doped with Mg, and the barrier layer of the third-wavelength multiple quantum well layer is a material layer that is not intentionally doped with Mg and Si.

[0009] In some embodiments, the well layers of each multi-quantum well layer are all InGaN layers.

[0010] The barrier layer of the first-wavelength multi-quantum well layer is the first barrier layer, and the first barrier layer includes a first Si-doped GaN layer, Al x Ga 1-x N layer and a second Si-doped GaN layer deposited in sequence along the epitaxial direction;

[0011] The barrier layer of the second-wavelength multi-quantum well layer is the second barrier layer, and the second barrier layer includes a first low-Si-doped GaN layer, Al y Ga 1-y N layer and a second low-Si-doped GaN layer, where x > y;

[0012] The barrier layer of the third-wavelength multi-quantum well layer is the third barrier layer, and the third barrier layer includes at least one layer of unintentionally doped GaN layer;

[0013] The barrier layer of the fourth-wavelength multi-quantum well layer is the fourth barrier layer, and the fourth barrier layer includes an unintentionally doped GaN layer, a first Mg-doped Al z Ga 1-z-i In i N layer, a second Mg-doped Al k Ga 1-k-j In j N layer and a Mg-doped GaN layer deposited in sequence along the epitaxial direction.

[0014] In some embodiments, the Si doping concentration of the first barrier layer is greater than that of the second barrier layer;

[0015] In the first-wavelength multi-quantum well layer, the Si doping concentration of the first barrier layer decreases periodically along the epitaxial direction, and in the same first barrier layer, the Si doping concentration of the first Si-doped GaN layer is equal to or greater than that of the second Si-doped GaN layer;

[0016] In the second-wavelength multi-quantum well layer, the Si doping concentration of the second barrier layer decreases periodically along the epitaxial direction, and in the same second barrier layer, the Si doping concentration of the first low-Si-doped GaN layer is equal to or greater than that of the second low-Si-doped GaN layer.

[0017] In some embodiments, in the first barrier layer, the Si doping concentration of the first Si-doped GaN layer is 1.18×10 17 / cm 3 ~7.56×10 17 / cm 3 and the Si doping concentration of the second Si-doped GaN layer is 1.18×1017 / cm 3 ~7.56×10 17 / cm 3 ;

[0018] In the second stack layer, the Si doping concentration of the first low-Si-doped GaN layer is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 , and the Si doping concentration of the second low-Si-doped GaN layer is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 .

[0019] In some embodiments, in the same fourth stack layer, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer and the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer are both less than the Mg doping concentration of the Mg-doped GaN layer.

[0020] In some embodiments, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 , and the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 , and the Mg doping concentration of the Mg-doped GaN layer is 2.8×10 18 / cm 3 ~7.6×10 19 / cm 3 .

[0021] In some embodiments, x > y > z = k, j > i.

[0022] In some embodiments, 0.02 ≤ x ≤ 0.28, 0.01 < y ≤ 0.19, 0.01 ≤ z = k ≤ 0.07, 0.02 ≤ j ≤ 0.12, 0.01 ≤ i ≤ 0.08.

[0023] In some embodiments, the number of periods of the second wavelength multiple quantum well layer and the number of periods of the third wavelength multiple quantum well layer are both greater than the number of periods of the fourth wavelength multiple quantum well layer, and the number of periods of the first wavelength multiple quantum well layer is equal to or greater than the number of periods of the fourth wavelength multiple quantum well layer.

[0024] Secondly, the present invention provides a white light LED light source, comprising a fluorescent glue layer and the above-mentioned LED chip, and the fluorescent glue layer comprises a red phosphor and a green phosphor.

[0025] The beneficial effects of the present invention are as follows:

[0026] In the present invention, a first wavelength multiple quantum well layer, a second wavelength multiple quantum well layer, a third wavelength multiple quantum well layer, and a fourth wavelength multiple quantum well layer are sequentially stacked along the epitaxial direction in the light-emitting layer of the LED chip, and the emission wavelengths of the respective multiple quantum well layers are controlled. While setting the emission wavelengths corresponding to the respective multiple quantum well layers to λ1 > λ2 > λ3 = λ4, Si is doped in the barrier layers of the first wavelength multiple quantum well layer and the second wavelength multiple quantum well layer, Mg is doped in the barrier layer of the fourth wavelength multiple quantum well layer, and the barrier layer of the third wavelength multiple quantum well layer is a material layer that is not intentionally doped with Mg and Si. Through the mutual cooperation between multiple multiple quantum well layers emitting different wavelengths, the red phosphor and the green phosphor are fully excited, the overall excitation efficiency is effectively improved, the spectral gaps when exciting the red phosphor and the green phosphor are compensated for each other, and the red light, green light, and the excitation light that is not absorbed and directly transmitted through at each wavelength can form a more continuous, smoother, and more natural light-like spectrum. The color rendering index of the output full-spectrum white light LED light source is higher, and at the same time, it has a higher luminous efficiency. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of an LED chip according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic structural diagram of the light-emitting layer of the LED chip according to an embodiment of the present invention.

[0029] Figure 3 It is a schematic structural diagram of a single period of the first wavelength multiple quantum well layer according to an embodiment of the present invention.

[0030] Figure 4 It is a schematic structural diagram of a single period of the second wavelength multiple quantum well layer according to an embodiment of the present invention.

[0031] Figure 5 Schematic diagram of a single period of the third wavelength multi - quantum well layer according to an embodiment of the present invention.

[0032] Figure 6 Schematic diagram of a single period of the fourth wavelength multi - quantum well layer according to an embodiment of the present invention. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below.

[0034] First, as shown in Figures 1 to 2 The present invention provides an LED chip, including a substrate 1 and an epitaxial layer disposed on the substrate 1. The epitaxial layer includes a buffer layer 2, an N - type layer 3, a low - temperature stress - release layer 4, a light - emitting layer 5, an electron - blocking layer 6 and a P - type layer 7 arranged in sequence along the epitaxial direction;

[0035] The light - emitting layer 5 includes a first - wavelength multi - quantum well layer 51, a second - wavelength multi - quantum well layer 52, a third - wavelength multi - quantum well layer 53 and a fourth - wavelength multi - quantum well layer 54 stacked in sequence along the epitaxial direction;

[0036] The emission wavelength of the first - wavelength multi - quantum well layer 51 is λ1, the emission wavelength of the second - wavelength multi - quantum well layer 52 is λ2, the emission wavelength of the third - wavelength multi - quantum well layer 53 is λ3, and the emission wavelength of the fourth - wavelength multi - quantum well layer 54 is λ4. Among them, λ1>λ2>λ3 = λ4, and 460nm≤λ1≤480nm, 445nm≤λ2≤460nm, 430nm≤λ3 = λ4≤445nm;

[0037] Each multi - quantum well layer is a periodic structure formed by alternately stacking well layers and barrier layers. Si is doped in the barrier layers of the first - wavelength multi - quantum well layer 51 and the second - wavelength multi - quantum well layer 52, Mg is doped in the barrier layers of the fourth - wavelength multi - quantum well layer 54, and the barrier layer of the third - wavelength multi - quantum well layer 53 is a material layer without deliberately doping Mg and Si.

[0038] In the LED chip of the present invention, the light-emitting layer 5 includes a first-wavelength multiple quantum well layer 51, a second-wavelength multiple quantum well layer 52, a third-wavelength multiple quantum well layer 53, and a fourth-wavelength multiple quantum well layer 54 that are sequentially stacked along the epitaxial direction. The emission wavelength λ1 of the first-wavelength multiple quantum well layer 51 satisfies 460 nm ≤ λ1 ≤ 480 nm, the emission wavelength λ2 of the second-wavelength multiple quantum well layer 52 satisfies 445 nm ≤ λ2 ≤ 460 nm, the emission wavelength λ3 of the third-wavelength multiple quantum well layer 53 and the emission wavelength λ4 of the fourth-wavelength multiple quantum well layer 54 satisfy 430 nm ≤ λ3 = λ4 ≤ 445 nm, and λ1 > λ2 > λ3 = λ4. Through the mutual cooperation between multiple multiple quantum well layers emitting different wavelengths, the LED chip can simultaneously emit excitation lights of multiple different bands, fully exciting the red phosphor and the green phosphor. The lights of different bands act synergistically to enhance the luminescence effect of the phosphor. When lights of multiple wavelengths act together, they can more comprehensively match the absorption spectrum of the phosphor. And because λ1 > λ2 > λ3 = λ4, when the LED chip emits light along the epitaxial direction, the low-energy long-wavelength light emitted by the front multiple quantum well layer is not easily absorbed by the subsequent short-wavelength multiple quantum well layer, effectively reducing the self-absorption loss of light, thereby effectively improving the overall excitation efficiency. At the same time, the cooperation between excitation lights of multiple different bands can make up for the spectral gaps in exciting the red phosphor and the green phosphor. The red light, green light, and the excitation light that is not absorbed and directly transmitted by each wavelength of light generated by the excitation can form a more continuous, smoother, and more natural-light-like spectrum, effectively improving the color rendering index.

[0039] Secondly, while setting the emission wavelengths corresponding to each multiple quantum well layer to λ1 > λ2 > λ3 = λ4 in the present invention, Si is doped in the barrier layers of the first-wavelength multiple quantum well layer 51 and the second-wavelength multiple quantum well layer 52, and Mg is doped in the barrier layer of the fourth-wavelength multiple quantum well layer 54, while the barrier layer of the third-wavelength multiple quantum well layer 53 is a material layer that is not deliberately doped with Mg and Si. Among them, Si is doped in the barrier layers of the long-wavelength multiple quantum well layers (the first-wavelength multiple quantum well layer 51 and the second-wavelength multiple quantum well layer 52). The local states introduced by Si are combined with the characteristics of the long-wavelength multiple quantum well layers, changing the electron migration from continuous diffusion to step-by-step tunneling. Compared with the electron retardation design that only depends on the barrier height, this cooperation method can achieve more controllable electron deceleration, increase the residence time of electrons in the light-emitting layer 5, and reduce the electron overshoot to the P-type layer 7, resulting in electron overflow. At the same time, the Mg doping of the short-wavelength quantum well layer (the fourth-wavelength multiple quantum well layer 54) realizes hole acceleration injection through polarization field regulation. The two work together to enable more effective electron-hole recombination to occur in the light-emitting layer 5, so that the overall light-emitting layer 5 can have better color rendering index and luminescence efficiency.

[0040] Accordingly, in the present invention, a first-wavelength multiple quantum well layer 51, a second-wavelength multiple quantum well layer 52, a third-wavelength multiple quantum well layer 53, and a fourth-wavelength multiple quantum well layer 54 are sequentially stacked along the epitaxial direction in the light-emitting layer 5 of the LED chip. The emission wavelengths of the respective multiple quantum well layers are controlled. While setting the emission wavelengths corresponding to the respective multiple quantum well layers as λ1 > λ2 > λ3 = λ4, Si is doped in the barrier layers of the first-wavelength multiple quantum well layer 51 and the second-wavelength multiple quantum well layer 52, and Mg is doped in the barrier layer of the fourth-wavelength multiple quantum well layer 54. The barrier layer of the third-wavelength multiple quantum well layer 53 is a material layer that is not intentionally doped with Mg and Si. Through the mutual cooperation between multiple multiple quantum well layers emitting different wavelengths, the red phosphor and the green phosphor are fully excited, effectively improving the overall excitation efficiency, making up for the spectral gaps when exciting the red phosphor and the green phosphor respectively. The red light, green light, and the excitation light that is not absorbed and directly transmitted at each wavelength can form a more continuous, smoother, and more natural light-like spectrum. The color rendering index of the output full-spectrum white LED light source is higher, and at the same time, it has a higher luminous efficiency.

[0041] Exemplarily, the emission wavelength λ1 of the first-wavelength multiple quantum well layer 51 is 460 nm, 462 nm, 465 nm, 468 nm, 470 nm, 472 nm, 475 nm, 478 nm, or 480 nm, but not limited thereto.

[0042] Exemplarily, the emission wavelength λ2 of the second-wavelength multiple quantum well layer 52 is 445 nm, 448 nm, 450 nm, 452 nm, 455 nm, 458 nm, or 460 nm, but not limited thereto.

[0043] Exemplarily, the emission wavelength λ3 of the third-wavelength multiple quantum well layer 53 is 430 nm, 432 nm, 435 nm, 438 nm, 440 nm, 442 nm, or 445 nm, but not limited thereto.

[0044] Exemplarily, the emission wavelength λ4 of the fourth-wavelength multiple quantum well layer 54 is 430 nm, 432 nm, 435 nm, 438 nm, 440 nm, 442 nm, or 445 nm, but not limited thereto.

[0045] In some embodiments, as shown in Figures 2 to 6 each well layer of the respective multiple quantum well layers is an InGaN layer.

[0046] The barrier layer of the first-wavelength multiple quantum well layer 51 is a first barrier layer 51B, and the first barrier layer 51B includes a first Si-doped GaN layer 511, an Al x Ga 1-x N layer 512, and a second Si-doped GaN layer 513 that are sequentially deposited along the epitaxial direction;

[0047] The barrier layer of the second-wavelength multi-quantum well layer 52 is the second barrier layer 52B, and the second barrier layer 52B includes a first low-Si-doped GaN layer 521, Al y Ga 1-y N layer 522, and a second low-Si-doped GaN layer 523 deposited in sequence along the epitaxial direction, where x > y;

[0048] The barrier layer of the third-wavelength multi-quantum well layer 53 is the third barrier layer 53B, and the third barrier layer 53B includes at least one unintentionally doped GaN layer;

[0049] The barrier layer of the fourth-wavelength multi-quantum well layer 54 is the fourth barrier layer 54B, and the fourth barrier layer 54B includes an unintentionally doped GaN layer 541, a first Mg-doped Al z Ga 1-z-i In i N layer 542, a second Mg-doped Al k Ga 1-k-j In j N layer 543, and a Mg-doped GaN layer 544.

[0050] Among them, the well layers of each multi-quantum well layer are all InGaN layers. Specifically, for the convenience of description, the well layer of the first-wavelength multi-quantum well layer 51 is denoted as the first InGaN layer 51A, the well layer of the second-wavelength multi-quantum well layer 52 is denoted as the second InGaN layer 52A, the well layer of the third-wavelength multi-quantum well layer 53 is denoted as the third InGaN layer 53A, and the well layer of the fourth-wavelength multi-quantum well layer 54 is denoted as the fourth InGaN layer 54A.

[0051] In the present invention, an AlGaN material layer (Al x Ga 1-x N layer 512, Al y Ga 1-y N layer 522) is introduced into the first barrier layer 51B and the second barrier layer 52B. The third barrier layer 53B is only an unintentionally doped GaN layer, and an AlGaInN material layer (the first Mg-doped Al z Ga 1-z-i In i N layer 542, the second Mg-doped Al k Ga 1-k-j In jFor the N-layer <543>, the band gaps of the first barrier layer <51B> to the fourth barrier layer <54B> decrease layer by layer. Combining with the emission wavelengths corresponding to each multiple quantum well layer decreasing layer by layer from the first-wavelength multiple quantum well layer <51> to the third-wavelength multiple quantum well layer <53> / fourth-wavelength multiple quantum well layer <54>, and the band gaps of the well layers increasing layer by layer. Thus, the potential barriers corresponding to each multiple quantum well layer decrease in sequence from the first-wavelength multiple quantum well layer <51> to the fourth-wavelength multiple quantum well layer <54>. The sequential decrease in the potential barriers of each multiple quantum well layer combined with the Si doping in the first barrier layer <51B> and the second barrier layer <52B> and the Mg doping in the fourth barrier layer <54B> achieve more controllable electron deceleration and hole acceleration injection. Among them, a part of the electrons recombine with the holes transported to this region in the first-wavelength multiple quantum well layer <51> and the second-wavelength multiple quantum well layer <52>. A part of the electrons are "slowly released" to the vicinity of the third-wavelength multiple quantum well layer <53> due to the stepped potential barriers and the Si doping in the first barrier layer <51B> and the second barrier layer <52B>. And part of the holes are gathered in the region of the third-wavelength multiple quantum well layer <53> due to the Mg acceleration in the fourth-wavelength multiple quantum well layer <54> and the undoped potential barrier in the third-wavelength multiple quantum well layer <53>. On the premise of ensuring that there are electrons and holes recombining in each multiple quantum well layer, more holes and electrons can gather near the third-wavelength multiple quantum well layer <53>, which is a high-energy multiple quantum well layer, and perform effective recombination, and the recombination probability is significantly improved. The third-wavelength multiple quantum well layer <53> has a higher energy, and the light emission efficiency of the light it emits is higher. Using the high energy excitation of the third-wavelength multiple quantum well layer <53> to compensate for the deficiency of long-wavelength light. Thus, it can not only ensure that the chip can form a more continuous, smoother, and more natural light-like spectrum under the cooperation of multiple quantum well layers with different emission wavelengths, but also ensure that it has a higher overall light emission efficiency.

[0052] Secondly, in the first barrier layer <51B> and the second barrier layer <52B>, introducing GaN material layers before and after the AlGaN material layer can ensure a higher lattice matching degree between the InGaN layer in the well layer and the AlGaN material layer in each multiple quantum well layer, and Si can be doped into the GaN material layer instead of the AlGaN material layer to avoid reducing the overall quality of the barrier layer due to the introduction of Si. In the fourth barrier layer <54B>, introducing GaN material layers before and after the AlGaInN material layer can ensure a higher lattice matching degree between the fourth InGaN layer <54A> and the AlGaInN material layer in the multiple quantum well layer, and Si can be doped into the GaN material layer instead of the AlGaInN material layer to avoid reducing the overall quality of the barrier layer due to the introduction of Si.

[0053] In some embodiments, the Si doping concentration of the first barrier layer <51B> is greater than the Si doping concentration of the second barrier layer <52B>;

[0054] In the first-wavelength multi-quantum well layer 51, the Si doping concentration of the first barrier layer 51B decreases periodically along the epitaxial direction, and in the same first barrier layer 51B, the Si doping concentration of the first Si-doped GaN layer 511 is equal to or greater than the Si doping concentration of the second Si-doped GaN layer 513;

[0055] In the second-wavelength multi-quantum well layer 52, the Si doping concentration of the second barrier layer 52B decreases periodically along the epitaxial direction, and in the same second barrier layer 52B, the Si doping concentration of the first low-Si-doped GaN layer 521 is equal to or greater than the Si doping concentration of the second low-Si-doped GaN layer 523.

[0056] By adjusting the Si doping concentrations inside the barrier layers of the first-wavelength multi-quantum well layer 51 and the second-wavelength multi-quantum well layer 52 and between the two, the migration rate of electrons in different regions is regulated, a more reasonable carrier distribution is achieved, the mutation during the electron migration process is avoided, it is ensured that electrons can move smoothly between the multi-quantum well layers, the problems of energy loss and reduced recombination efficiency caused by the mutation of the electron migration rate are reduced, the stability of electron migration in the entire light-emitting layer 5 is improved, and the continuity and smoothness of the spectrum are optimized. At the same time, through this Si doping setting, combined with the characteristic that the third barrier layer 53B is not deliberately doped, electrons are more likely to accumulate near the third-wavelength multi-quantum well layer 53, further improving the light-emitting efficiency.

[0057] In some embodiments, in the first barrier layer 51B, the Si doping concentration of the first Si-doped GaN layer 511 is 1.18×10 17 / cm 3 ~7.56×10 17 / cm 3 , and the Si doping concentration of the second Si-doped GaN layer 513 is 1.18×10 17 / cm 3 ~7.56×10 17 / cm 3 ;

[0058] In the second barrier layer 52B, the Si doping concentration of the first low-Si-doped GaN layer 521 is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 , and the Si doping concentration of the second low-Si-doped GaN layer 523 is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 .

[0059] Among them, the Si doping in the first stack layer 51B and the second stack layer 52B should not be too high, otherwise it is easy to cause an increase in the resistivity of the stack layer or an increase in non-radiative recombination, affecting the light-emitting efficiency.

[0060] Exemplarily, the Si doping concentration of the first Si-doped GaN layer 511 is 1.18×10 17 / cm 3 、1.2×10 17 / cm 3 、1.5×10 17 / cm 3 、1.8×10 17 / cm 3 、2.0×10 17 / cm 3 、2.2×10 17 / cm 3 、2.5×10 17 / cm 3 、2.8×10 17 / cm 3 、3.0×10 17 / cm 3 、3.2×10 17 / cm 3 、3.5×10 17 / cm 3 、3.8×10 17 / cm 3 、4.0×10 17 / cm 3 、4.2×10 17 / cm 3 、4.5×10 17 / cm 3 、4.8×10 17 / cm 3 、5.0×10 17 / cm 3 、5.2×10 17 / cm 3 、5.5×10 17 / cm 3 、5.8×10 17 / cm 3 、6.0×10 17 / cm 3 、6.2×10 17 / cm 3 、6.5×10 17 / cm 3 、6.8×10 17 / cm 3 、7.0×10 17 / cm3 , 7.2×10 17 / cm 3 , 7.5×10 17 / cm 3 or 7.56 × 10 17 / cm 3 , but not limited to this.

[0061] For example, the Si doping concentration of the second Si-doped GaN layer 513 is 1.18×10 17 / cm 3 , 1.2×10 17 / cm 3 , 1.5×10 17 / cm 3 , 1.8×10 17 / cm 3 , 2.0×10 17 / cm 3 , 2.2×10 17 / cm 3 , 2.5×10 17 / cm 3 , 2.8×10 17 / cm 3 , 3.0×10 17 / cm 3 , 3.2×10 17 / cm 3 , 3.5×10 17 / cm 3 , 3.8×10 17 / cm 3 4.0×10 17 / cm 3 4.2×10 17 / cm 3 , 4.5×10 17 / cm 3 , 4.8×10 17 / cm 3 , 5.0×10 17 / cm 3 , 5.2×10 17 / cm 3 , 5.5×10 17 / cm 3 , 5.8×10 17 / cm 3 , 6.0×10 17 / cm 3 , 6.2×10 17 / cm 3 , 6.5×10 17 / cm3 , 6.8×10 17 / cm 3 , 7.0×10 17 / cm 3 , 7.2×10 17 / cm 3 , 7.5×10 17 / cm 3 or 7.56×10 17 / cm 3 , but not limited to this.

[0062] Exemplarily, the Si doping concentration of the first low-doped GaN layer 521 is 1.0×10 17 / cm 3 , 1.2×10 17 / cm 3 , 1.5×10 17 / cm 3 , 1.8×10 17 / cm 3 , 2.0×10 17 / cm 3 , 2.2×10 17 / cm 3 , 2.5×10 17 / cm 3 , 2.8×10 17 / cm 3 , 3.0×10 17 / cm 3 , 3.2×10 17 / cm 3 , 3.5×10 17 / cm 3 , 3.8×10 17 / cm 3 , 4.0×10 17 / cm 3 , 4.2×10 17 / cm 3 , 4.5×10 17 / cm 3 , 4.8×10 17 / cm 3 , 5.0×10 17 / cm 3 , 5.2×10 17 / cm 3 , 5.5×10 17 / cm 3 , 5.8×10 17 / cm 3 , 6.0×10 17 / cm3 , 6.2×10 17 / cm 3 , 6.5×10 17 / cm 3 , 6.8×10 17 / cm 3 or 7.0×10 17 / cm 3 , but not limited thereto.

[0063] Exemplarily, the Si doping concentration of the second lowest doped Si-containing GaN layer 523 is 1.0×10 17 / cm 3 , 1.2×10 17 / cm 3 , 1.5×10 17 / cm 3 , 1.8×10 17 / cm 3 , 2.0×10 17 / cm 3 , 2.2×10 17 / cm 3 , 2.5×10 17 / cm 3 , 2.8×10 17 / cm 3 , 3.0×10 17 / cm 3 , 3.2×10 17 / cm 3 , 3.5×10 17 / cm 3 , 3.8×10 17 / cm 3 , 4.0×10 17 / cm 3 , 4.2×10 17 / cm 3 , 4.5×10 17 / cm 3 , 4.8×10 17 / cm 3 , 5.0×10 17 / cm 3 , 5.2×10 17 / cm 3 , 5.5×10 17 / cm 3 , 5.8×10 17 / cm 3 , 6.0×10 17 / cm 3 , 6.2×10 17 / cm3 , 6.5×10 17 / cm 3 , 6.8×10 17 / cm 3 or 7.0×10 17 / cm 3 , but not limited to this.

[0064] In some embodiments, in the same fourth barrier layer 54B, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer 542 and the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer 543 are both less than the Mg doping concentration of the Mg-doped GaN layer 544, which is beneficial to improving the overall quality of the fourth barrier layer 54B.

[0065] In some embodiments, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer 542 is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 , the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer 543 is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 , the Mg doping concentration of the Mg-doped GaN layer 544 is 2.8×10 18 / cm 3 ~7.6×10 19 / cm 3 .

[0066] The Mg doping concentration should not be too high, otherwise it may generate large stress inside the material, affecting the crystal structure and stability of the material.

[0067] Exemplarily, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer 542 is 2.5×10 18 / cm 3 , 3.0×10 18 / cm 3 , 3.5×10 18 / cm 3 、4.0×10 18 / cm 3 、4.5×10 18 / cm 3 、5.0×10 18 / cm 3 、5.5×10 18 / cm 3 、6.0×10 18 / cm 3 、6.5×10 18 / cm 3 、7.0×10 18 / cm 3 、7.5×10 18 / cm 3 、8.0×10 18 / cm 3 、8.5×10 18 / cm 3 、9.0×10 18 / cm 3 、1.0×10 19 / cm 3 、1.5×10 19 / cm 3 、2.0×10 19 / cm 3 、2.5×10 19 / cm 3 、3.0×10 19 / cm 3 、3.5×10 19 / cm 3 、4.0×10 19 / cm 3 、4.5×10 19 / cm 3 、5.0×10 19 / cm 3 、5.5×10 19 / cm 3 、6.0×10 19 / cm 3 、6.5×10 19 / cm 3 、7.0×10 19 / cm 3 or 7.2×10 19 / cm 3 ,but not limited thereto.

[0068] Exemplarily, the second Mg-doped Al k Ga 1-k-j Inj The Mg doping concentration of the N-layer 543 is 2.5×10 18 / cm 3 、3.0×10 18 / cm 3 、3.5×10 18 / cm 3 、4.0×10 18 / cm 3 、4.5×10 18 / cm 3 、5.0×10 18 / cm 3 、5.5×10 18 / cm 3 、6.0×10 18 / cm 3 、6.5×10 18 / cm 3 、7.0×10 18 / cm 3 、7.5×10 18 / cm 3 、8.0×10 18 / cm 3 、8.5×10 18 / cm 3 、9.0×10 18 / cm 3 、1.0×10 19 / cm 3 、1.5×10 19 / cm 3 、2.0×10 19 / cm 3 、2.5×10 19 / cm 3 、3.0×10 19 / cm 3 、3.5×10 19 / cm 3 、4.0×10 19 / cm 3 、4.5×10 19 / cm 3 、5.0×10 19 / cm 3 、5.5×10 19 / cm 3 、6.0×10 19 / cm 3 、6.5×10 19 / cm 3 、7.0×10 19 / cm 3or 7.2×10 19 / cm 3 , but not limited to this.

[0069] Exemplarily, the Mg doping concentration of the Mg-doped GaN layer 544 is 2.8×10 18 / cm 3 、3.0×10 18 / cm 3 、3.5×10 18 / cm 3 、4.0×10 18 / cm 3 、4.5×10 18 / cm 3 、5.0×10 18 / cm 3 、5.5×10 18 / cm 3 、6.0×10 18 / cm 3 、6.5×10 18 / cm 3 、7.0×10 18 / cm 3 、7.5×10 18 / cm 3 、8.0×10 18 / cm 3 、8.5×10 18 / cm 3 、9.0×10 18 / cm 3 、1.0×10 19 / cm 3 、1.5×10 19 / cm 3 、2.0×10 19 / cm 3 、2.5×10 19 / cm 3 、3.0×10 19 / cm 3 、3.5×10 19 / cm 3 、4.0×10 19 / cm 3 、4.5×10 19 / cm 3 、5.0×10 19 / cm 3 、5.5×10 19 / cm 3 、6.0×10 19 / cm 3 、6.5×1019 / cm 3 , 7.0×10 19 / cm 3 , 7.5×10 19 / cm 3 or 7.6×10 19 / cm 3 , but not limited to this.

[0070] In some embodiments, x>y>z=k, j>i.

[0071] As a result, the bandgap width of the first barrier layer 51B to the fourth barrier layer 54B forms a suitable barrier decreasing trend. Combined with the light emission wavelength corresponding to each multi-quantum well layer decreasing layer by layer from the first wavelength multi-quantum well layer 51 to the third wavelength multi-quantum well layer 53 / the fourth wavelength multi-quantum well layer 54, the bandgap width of the well layer increases layer by layer. As a result, the potential barrier corresponding to each multi-quantum well layer decreases from the first wavelength multi-quantum well layer 51 to the fourth wavelength multi-quantum well layer 54.

[0072] In some embodiments, 0.02≤x≤0.28, 0.01<y≤0.19, 0.01≤z=k≤0.07, 0.02≤j≤0.12, 0.01≤i≤0.08.

[0073] By controlling the content of each component, a suitable potential barrier difference is formed between the first wavelength multi-quantum well layer 51 to the fourth wavelength multi-quantum well layer 54 , which is beneficial to optimizing the transmission and distribution of carriers in the light-emitting layer 5 .

[0074] For example, Al x Ga 1-x In the N layer 512, x is 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28 or 0.29, but is not limited thereto.

[0075] For example, Al y Ga 1-y In the N layer 522, y is 0.015, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18 or 0.19, but is not limited thereto.

[0076] For example, the first Mg-doped Al z Ga1-z-i In i In the N-layer 542, z is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 or 0.07, but not limited thereto, and i is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, but not limited thereto.

[0077] Exemplarily, the second Mg-doped Al k Ga 1-k-j In j In the N-layer 543, k is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 or 0.07, but not limited thereto, and j is 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11 or 0.12, but not limited thereto.

[0078] In some embodiments, the number of periods of the second wavelength multiple quantum well layer 52 and the number of periods of the third wavelength multiple quantum well layer 53 are both greater than the number of periods of the fourth wavelength multiple quantum well layer 54, and the number of periods of the first wavelength multiple quantum well layer 51 is equal to or greater than the number of periods of the fourth wavelength multiple quantum well layer 54.

[0079] By regulating the number of periods of each multiple quantum well layer, the light emission ratio of each multiple quantum well layer is regulated, which is beneficial to improving the color rendering performance and light emission efficiency.

[0080] In some embodiments, the number of periods of the first wavelength multiple quantum well layer 51 is 1 to 5, the number of periods of the second wavelength multiple quantum well layer 52 is 2 to 6, the number of periods of the third wavelength is 2 to 5, and the number of periods of the fourth wavelength is 1.

[0081] Secondly, the present invention provides a white light LED light source, including a fluorescent glue layer and the above-mentioned LED chip, and the fluorescent glue layer includes a red phosphor and a green phosphor.

[0082] Exemplarily, the red phosphor can be at least one of a nitride red phosphor, a oxynitride red phosphor or a fluoride red phosphor. For example, CaAlSiN3:Eu 2+ 、Sr2Si5N8:Eu 2+ 、K2SiF6:Mn 4+ 。

[0083] Exemplarily, the green phosphor can be at least one of a silicate green phosphor, a oxynitride green phosphor or a garnet structure green phosphor. For example, β-SiAlON:Eu 2+ 、Lu3Al5O 12 :Ce 3+ 。

[0084] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0085] Embodiment 1

[0086] This embodiment discloses an LED chip, including a substrate and an epitaxial layer disposed on the substrate. The epitaxial layer includes a buffer layer, an N-type layer, a low-temperature stress release layer, a light-emitting layer, an electron blocking layer, and a P-type layer sequentially arranged along the epitaxial direction;

[0087] The light-emitting layer includes a first-wavelength multiple quantum well layer, a second-wavelength multiple quantum well layer, a third-wavelength multiple quantum well layer, and a fourth-wavelength multiple quantum well layer sequentially stacked along the epitaxial direction;

[0088] The emission wavelength of the first-wavelength multiple quantum well layer is λ1, the emission wavelength of the second-wavelength multiple quantum well layer is λ2, the emission wavelength of the third-wavelength multiple quantum well layer is λ3, and the emission wavelength of the fourth-wavelength multiple quantum well layer is λ4, where λ1 > λ2 > λ3 = λ4, and λ1 = 480 nm, λ2 = 460 nm, λ3 = λ4 = 445 nm;

[0089] Each multiple quantum well layer is a periodic structure formed by alternating well layers and barrier layers. Si is doped in the barrier layers of the first-wavelength multiple quantum well layer and the second-wavelength multiple quantum well layer, Mg is doped in the barrier layer of the fourth-wavelength multiple quantum well layer, and the barrier layer of the third-wavelength multiple quantum well layer is a material layer that is not intentionally doped with Mg and Si.

[0090] In this embodiment, the well layers of each multiple quantum well layer are all InGaN layers,

[0091] The barrier layer of the first-wavelength multiple quantum well layer is the first barrier layer, and the first barrier layer includes a first Si-doped GaN layer, Al x Ga 1-x N layer, and a second Si-doped GaN layer sequentially deposited along the epitaxial direction;

[0092] The barrier layer of the second-wavelength multiple quantum well layer is the second barrier layer, and the second barrier layer includes a first low-Si-doped GaN layer, Al y Ga 1-y N layer, and a second low-Si-doped GaN layer sequentially deposited along the epitaxial direction, where x > y;

[0093] The barrier layer of the third-wavelength multiple quantum well layer is the third barrier layer, and the third barrier layer includes at least one layer of unintentionally doped GaN layer;

[0094] The barrier layer of the fourth-wavelength multiple quantum well layer is the fourth barrier layer, and the fourth barrier layer includes an unintentionally doped GaN layer, a first Mg-doped Al z Ga 1-z-i In iN-layer, second Mg-doped Al k Ga 1-k-j In j N-layer and Mg-doped GaN layer.

[0095] In this embodiment, the Si doping concentration of the first barrier layer is greater than that of the second barrier layer;

[0096] In the first wavelength multi-quantum well layer, the Si doping concentration of the first barrier layer decreases periodically along the epitaxial direction, and in the same first barrier layer, the Si doping concentration of the first Si-doped GaN layer is equal to that of the second Si-doped GaN layer. Specifically, from the first period to the last period, the Si doping concentrations of both the first Si-doped GaN layer and the second Si-doped GaN layer decrease from 7.56×10 17 / cm 3 to 6.5×10 17 / cm 3 ;

[0097] In the second wavelength multi-quantum well layer, the Si doping concentration of the second barrier layer decreases periodically along the epitaxial direction, and in the same second barrier layer, the Si doping concentration of the first low-Si-doped GaN layer is equal to that of the second low-Si-doped GaN layer. Specifically, from the first period to the last period, the Si doping concentrations of both the first low-Si-doped GaN layer and the second low-Si-doped GaN layer decrease from 6×10 17 / cm 3 to 5×10 17 / cm 3 .

[0098] In this embodiment, in the same fourth barrier layer, the Mg doping concentrations of the first Mg-doped Al z Ga 1-z-i In i N layer and the second Mg-doped Al k Ga 1-k-j In j N layer are both less than the Mg doping concentration of the Mg-doped GaN layer, which is beneficial to improving the overall quality of the fourth barrier layer.

[0099] In this embodiment, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer is 7.2×10 19 / cm 3 , and the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer is 7.2×10 19 / cm3 , the Mg doping concentration of the Mg-doped GaN layer is 7.6×10 19 / cm 3 .

[0100] In this embodiment, x > y > z = k, j > i.

[0101] In this embodiment, x = 0.28, y = 0.19, z = k = 0.07, i = 0.08, j = 0.12.

[0102] In this embodiment, the number of periods of the second-wavelength multi-quantum well layer and the number of periods of the third-wavelength multi-quantum well layer are both greater than the number of periods of the fourth-wavelength multi-quantum well layer, and the number of periods of the first-wavelength multi-quantum well layer is equal to or greater than the number of periods of the fourth-wavelength multi-quantum well layer.

[0103] In this embodiment, the number of periods of the first-wavelength multi-quantum well layer is 3, the number of periods of the second-wavelength multi-quantum well layer is 3, the number of periods of the third wavelength is 5, and the number of periods of the fourth wavelength is 1.

[0104] Secondly, the present invention provides a white light LED light source, including a fluorescent glue layer and the above-mentioned LED chip, and the fluorescent glue layer includes a red phosphor and a green phosphor.

[0105] Example 2

[0106] The difference between this embodiment and Embodiment 1 is that the emission wavelength of the first-wavelength multi-quantum well layer is λ1, the emission wavelength of the second-wavelength multi-quantum well layer is λ2, the emission wavelength of the third-wavelength multi-quantum well layer is λ3, and the emission wavelength of the fourth-wavelength multi-quantum well layer is λ4, where λ1 > λ2 > λ3 = λ4, and λ1 = 460 nm, λ2 = 440 nm, λ3 = λ4 = 430 nm.

[0107] Example 3

[0108] The difference between this embodiment and Embodiment 1 is that the emission wavelength of the first-wavelength multi-quantum well layer is λ1, the emission wavelength of the second-wavelength multi-quantum well layer is λ2, the emission wavelength of the third-wavelength multi-quantum well layer is λ3, and the emission wavelength of the fourth-wavelength multi-quantum well layer is λ4, where λ1 > λ2 > λ3 = λ4, and λ1 = 475 nm, λ2 = 455 nm, λ3 = λ4 = 435 nm.

[0109] Example 4

[0110] The difference between this embodiment and Embodiment 1 is that the Si doping concentration of the first barrier layer is equal to the Si doping concentration of the second barrier layer.

[0111] In the first-wavelength multi-quantum well layer, the Si doping concentration of each first barrier layer is kept consistent. Specifically, from the first period to the last period, the Si doping concentration of the first Si-doped GaN layer and the Si doping concentration of the second Si-doped GaN layer are both 7×10 17 / cm 3 ;

[0112] In the second-wavelength multi-quantum well layer, the Si doping concentration of each second barrier layer is kept consistent. Specifically, from the first period to the last period, the Si doping concentration of the first low-Si-doped GaN layer and the Si doping concentration of the second low-Si-doped GaN layer are both 7×10 17 / cm 3 .

[0113] Example 5

[0114] The difference between this example and Example 1 is that in this example, x = 0.03, y = 0.02, z = k = 0.01.

[0115] Example 6

[0116] The difference between this example and Example 1 is that in this example, x = 0.20, y = 0.10, z = k = 0.04.

[0117] Example 7

[0118] The difference between this example and Example 1 is that in this example, the number of periods of the first-wavelength multi-quantum well layer to the fourth-wavelength multi-quantum well layer is 3 each.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is that in the first-wavelength multi-quantum well layer and the second-wavelength multi-quantum well layer, Si is not intentionally doped in the barrier layers, and in the fourth-wavelength multi-quantum well layer, Mg is not intentionally doped in the barrier layers, that is:

[0121] The barrier layer of the first-wavelength multi-quantum well layer is the first barrier layer, and the first barrier layer includes a first GaN layer, an Al x Ga 1-x N layer and a second GaN layer deposited in sequence along the epitaxial direction;

[0122] The barrier layer of the second-wavelength multi-quantum well layer is the second barrier layer, and the second barrier layer includes a first GaN layer, an Al y Ga 1-y N layer and a second GaN layer deposited in sequence along the epitaxial direction, where x > y;

[0123] The barrier layer of the third-wavelength multi-quantum well layer is the third barrier layer, and the third barrier layer includes at least one unintentionally doped GaN layer;

[0124] The barrier layer of the fourth-wavelength multi-quantum well layer is the fourth barrier layer, and the fourth barrier layer includes an unintentionally doped GaN layer, a first Al z Ga 1-z-i In i N layer, a second Al k Ga 1-k-j In j N layer, and a GaN layer, which are sequentially deposited along the epitaxial direction.

[0125] Comparative Example 2

[0126] The difference between this comparative example and Example 1 is that in the light-emitting layer of this comparative example, the emission wavelength of the first-wavelength multi-quantum well layer is equal to the emission wavelength of the second-wavelength multi-quantum well layer, and the emission wavelengths of the second-wavelength multi-quantum well layer to the fourth-wavelength multi-quantum well layer increase sequentially.

[0127] Specifically, the emission wavelength of the first-wavelength multi-quantum well layer is λ1, the emission wavelength of the second-wavelength multi-quantum well layer is λ2, the emission wavelength of the third-wavelength multi-quantum well layer is λ3, and the emission wavelength of the fourth-wavelength multi-quantum well layer is λ4, where λ1 = λ2 < λ3 < λ4, and λ1 = 445 nm, λ3 = 460 nm, and λ4 = 480 nm.

[0128] Comparative Example 3

[0129] The difference between this comparative example and Example 1 is that in this comparative example, the emission wavelengths of the first-wavelength multi-quantum well layer to the fourth-wavelength multi-quantum well layer are all 445 nm.

[0130] Test the electrical parameters of the above Examples 1 to 7 and Comparative Examples 1 to 3, calculate the luminous efficiency improvement rate of the remaining experimental groups relative to Comparative Example 3, and test the color rendering performance of each experimental group. The test results are as follows:

[0131]

[0132] Comparing Examples 1 to 3 and Comparative Examples 2 to 3, it can be seen that the coordinated setting of the emission wavelengths of the multi-quantum well layers in the light-emitting layer of the present invention is beneficial to improving the color rendering index and luminous efficiency.

[0133] Comparing Example 1, Example 4 and Comparative Example 1, it can be seen that in the present application, the decreasing doping setting of Si in the first-wavelength multi-quantum well layer and the second-wavelength multi-quantum well layer and the doping setting of Mg in the fourth-wavelength multi-quantum well layer are beneficial to improving the luminous efficiency.

[0134] Comparing Example 1, Example 5 and Example 6, it can be seen that the setting of the barrier height in each multi-quantum well layer of the present invention can affect the luminous efficiency.

[0135] Comparing Comparative Example 1 and Example 7, it can be seen that in the present invention, the number of periods of the second-wavelength multiple quantum well layer and the number of periods of the third-wavelength multiple quantum well layer are both greater than the number of periods of the fourth-wavelength multiple quantum well layer. The setting that the number of periods of the first-wavelength multiple quantum well layer is equal to or greater than the number of periods of the fourth-wavelength multiple quantum well layer is beneficial to improving the color rendering index.

[0136] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the technical content prompted above within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention.

Claims

1. An LED chip, comprising a substrate and an epitaxial layer disposed on the substrate, characterized in that, The epitaxial layer includes a buffer layer, an N-type layer, a low-temperature stress relaxation layer, a light-emitting layer, an electron blocking layer, and a P-type layer, which are sequentially arranged along the epitaxial direction; The light-emitting layer includes a first-wavelength multiple quantum well layer, a second-wavelength multiple quantum well layer, a third-wavelength multiple quantum well layer, and a fourth-wavelength multiple quantum well layer, which are sequentially stacked along the epitaxial direction; The light-emitting wavelength of the first-wavelength multiple quantum well layer is λ1, the light-emitting wavelength of the second-wavelength multiple quantum well layer is λ2, the light-emitting wavelength of the third-wavelength multiple quantum well layer is λ3, and the light-emitting wavelength of the fourth-wavelength multiple quantum well layer is λ4, where λ1 > λ2 > λ3 = λ4, and 460 nm ≤ λ1 ≤ 480 nm, 445 nm ≤ λ2 ≤ 460 nm, 430 nm ≤ λ3 = λ4 ≤ 445 nm; Each multiple quantum well layer is a periodic structure formed by alternating well layers and barrier layers. Si is doped in the barrier layer of the first-wavelength multiple quantum well layer and the barrier layer of the second-wavelength multiple quantum well layer. Mg is doped in the barrier layer of the fourth-wavelength multiple quantum well layer. The barrier layer of the third-wavelength multiple quantum well layer is a material layer that is not intentionally doped with Mg and Si.

2. An LED chip according to claim 1, wherein The well layer of each multiple quantum well layer is an InGaN layer. The barrier layer of the first wavelength multiple quantum well layer is the first barrier layer, and the first barrier layer includes a first Si-doped GaN layer, Al x Ga 1-x N layer and a second Si-doped GaN layer deposited in sequence along the epitaxial direction; The barrier layer of the second wavelength multi-quantum well layer is the second barrier layer, and the second barrier layer includes a first low-Si-doped GaN layer, Al y Ga 1-y N layer and a second low-Si-doped GaN layer, where x > y; The barrier layer of the third-wavelength multiple quantum well layer is the third barrier layer, and the third barrier layer includes at least one unintentionally doped GaN layer; The barrier layer of the fourth-wavelength multiple quantum well layer is the fourth barrier layer, and the fourth barrier layer includes an unintentionally doped GaN layer, a first Mg-doped Al z Ga 1-z-i In i N layer, a second Mg-doped Al k Ga 1-k-j In j N layer, and a Mg-doped GaN layer deposited in sequence along the epitaxial direction.

3. An LED chip according to claim 2, characterized in that, The Si doping concentration of the first barrier layer is greater than the Si doping concentration of the second barrier layer; In the first-wavelength multiple quantum well layer, the Si doping concentration of the first barrier layer decreases periodically along the epitaxial direction, and in the same first barrier layer, the Si doping concentration of the first Si-doped GaN layer is equal to or greater than the Si doping concentration of the second Si-doped GaN layer; In the second-wavelength multiple quantum well layer, the Si doping concentration of the second barrier layer decreases periodically along the epitaxial direction, and in the same second barrier layer, the Si doping concentration of the first low-Si-doped GaN layer is equal to or greater than the Si doping concentration of the second low-Si-doped GaN layer.

4. An LED chip according to claim 2, characterized in that, In the first buffer layer, the Si doping concentration of the first Si-doped GaN layer is 1.18×10 17 / cm 3 ~7.56×10 17 / cm 3 , and the Si doping concentration of the second Si-doped GaN layer is 1.18×10 17 / cm 3 ~7.56×10 17 / cm 3 ; In the second buffer layer, the Si doping concentration of the first low-Si-doped GaN layer is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 ; and the Si doping concentration of the second low-Si-doped GaN layer is 1.0×10 17 / cm 3 ~7.0×10 17 / cm 3 .

5. An LED chip according to claim 2, wherein, In the same fourth barrier layer, the Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer and the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer are both less than the Mg doping concentration of the Mg-doped GaN layer.

6. An LED chip according to claim 5, characterized in that, The Mg doping concentration of the first Mg-doped Al z Ga 1-z-i In i N layer is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 ; the Mg doping concentration of the second Mg-doped Al k Ga 1-k-j In j N layer is 2.5×10 18 / cm 3 ~7.2×10 19 / cm 3 ; the Mg doping concentration of the Mg-doped GaN layer is 2.8×10 18 / cm 3 ~7.6×10 19 / cm 3 .

7. An LED chip according to claim 2, characterized in that, x > y > z = k, j > i.

8. An LED chip according to claim 7, characterized in that, 0.02 ≤ x ≤ 0.28, 0.01 < y ≤ 0.19, 0.01 ≤ z = k ≤ 0.07, 0.02 ≤ j ≤ 0.12, 0.01 ≤ i ≤ 0.

08.

9. An LED chip according to claim 2, characterized in that, The number of periods of the second-wavelength multiple quantum well layer and the number of periods of the third-wavelength multiple quantum well layer are both greater than the number of periods of the fourth-wavelength multiple quantum well layer, and the number of periods of the first-wavelength multiple quantum well layer is equal to or greater than the number of periods of the fourth-wavelength multiple quantum well layer.

10. A white light LED light source, characterized in that, It includes a fluorescent glue layer and the LED chip according to any one of claims 1 to 9. The fluorescent glue layer includes red fluorescent powder and green fluorescent powder.

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