Dual-band LED epitaxial wafer and preparation method thereof

Abstract

This invention relates to the field of semiconductor technology and discloses a dual-band LED epitaxial wafer and its fabrication method. The wafer comprises, sequentially arranged along the epitaxial direction, a substrate, a buffer layer, a first N-type semiconductor layer, a first stress relief layer, a first green quantum well layer, a second N-type semiconductor layer, a second stress relief layer, a blue quantum well layer, an electron blocking layer, a P-type semiconductor layer, a second green quantum well layer, and a P-type ohmic contact layer. Using this invention, while reducing the use of phosphors and lowering manufacturing costs, it not only improves color rendering performance and green light enhancement performance but also helps to increase luminous efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a dual-band LED epitaxial wafer and its preparation method. Background Technology

[0002] Light-emitting diodes (LEDs) are devices that efficiently convert electrical energy into light energy. They release light by recombination of electrons and holes and are widely used in lighting, displays, and other fields.

[0003] Currently, LED backlight sources used in the display field are mainly divided into the following two categories: (1) RGB-LED scheme. This scheme achieves three-primary-color emission by independently packaging three monochrome chips of red, green and blue, which has the advantages of wide color gamut and good color performance. However, this scheme requires the preparation of epitaxial wafers of three different material systems and independent processing into chips. The process complexity of epitaxial growth and chip manufacturing is high, the material utilization rate is low, and the single-wafer production capacity is limited, resulting in high overall manufacturing costs; (2) White LED scheme. It achieves white light emission by combining monochrome LED chips with phosphors, such as combining blue chips with green and red phosphors, or combining blue chips with yellow phosphors. Although this scheme has a lower cost, phosphors are prone to aging and failure in high temperature and high humidity environments, and the conversion efficiency decreases. At the same time, thermal light decay leads to luminous flux degradation and wavelength shift, ultimately deteriorating the color rendering performance.

[0004] Therefore, how to improve color development performance while reducing the use of phosphors and lowering costs has become an urgent technical issue to be addressed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a dual-band LED epitaxial wafer and its preparation method, which is beneficial to improve not only color rendering performance and green light enhancement performance, but also luminous efficiency, while reducing the use of phosphor and reducing manufacturing costs.

[0006] To solve the above-mentioned technical problems, the present invention provides a dual-band LED epitaxial wafer, comprising a substrate, a buffer layer, a first N-type semiconductor layer, a first stress relief layer, a first green quantum well layer, a second N-type semiconductor layer, a second stress relief layer, a blue quantum well layer, an electron blocking layer, a P-type semiconductor layer, a second green quantum well layer, and a P-type ohmic contact layer arranged sequentially along the epitaxial direction. The first stress relief layer includes a first InGaN layer and a first Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction; The second stress relief layer includes a second InGaN layer and a second Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction; The first green quantum well layer includes a green InGaN layer and a green Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The blue quantum well layer includes a blue InGaN layer and a blue Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The second green quantum well layer includes a green Mg-doped InGaN layer and a green Mg-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The In composition content of the first InGaN layer is X1, the In composition content of the second InGaN layer is X2, the In composition content of the green InGaN layer is X3, the In composition content of the blue InGaN layer is X4, and the In composition content of the green Mg-doped InGaN layer is X5, which satisfies X1 < X4 < X3 = X5 and X2 < X4 < X3 = X5.

[0007] In some embodiments, the difference between X4 and X1 ranges from 0.03 to 0.17; And / or, the difference between X4 and X2 ranges from 0.03 to 0.17; And / or, the difference between X3 and X4 is in the range of 0.03 to 0.23.

[0008] In some embodiments, the first InGaN layer satisfies the following condition: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1050℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the first Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1080℃; (4) The growth pressure is 30 torr to 360 torr.

[0009] In some embodiments, the second InGaN layer satisfies the following condition: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the second Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1020℃; (4) The growth pressure is 30 torr to 360 torr.

[0010] In some embodiments, the green InGaN layer satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 1 nm to 6 nm; (4) The growth temperature is 650℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 3nm to 30nm; (3) The growth temperature is 800℃~1050℃; (4) The growth pressure is 30 torr to 360 torr.

[0011] In some embodiments, the blue InGaN layer satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.05-0.19; (3) The growth thickness is 2nm to 5nm; (4) The growth temperature is 720℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the blue light Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.5 × 10⁻⁶. 17 / cm 3 ~8.6×10 17 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 760℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

[0012] In some embodiments, the green Mg-doped InGaN layer satisfies the following conditions: (1) The doping concentration of Mg is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 2.1 nm to 4.8 nm; (4) The growth temperature is 680℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Mg-doped GaN layer satisfies the following condition: (1) The Mg doping concentration is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 780℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

[0013] This invention also proposes a method for fabricating a dual-band LED epitaxial wafer, used to fabricate the dual-band LED epitaxial wafer as described above, comprising: A buffer layer is grown on the substrate; A first N-type semiconductor layer is grown on the buffer layer; A first stress-relieving layer is grown on the first N-type semiconductor layer; A first green quantum well layer is grown on the first stress-relieving layer; A second N-type semiconductor layer is grown on the first green quantum well layer; A second stress-relieving layer is grown on the second N-type semiconductor layer; A blue quantum well layer is grown on the second stress-relieving layer; An electron blocking layer is grown on a blue quantum well layer. A P-type semiconductor layer is grown on an electron blocking layer. A second green quantum well layer is grown on a P-type semiconductor layer; A P-type ohmic contact layer was grown on the second green quantum well layer to obtain a dual-band LED epitaxial wafer.

[0014] Implementing this invention has the following beneficial effects: 1. A portion of the blue light emitted by the electroluminescence of the blue quantum well layer can penetrate the second N-type semiconductor layer and enter the green InGaN layer of the first green quantum well layer. Since the In content of the blue InGaN layer is less than that of the green InGaN layer, and the bandgap of InGaN is negatively correlated with the In content, the bandgap of the green InGaN layer is smaller than that of the blue InGaN layer. This bandgap design allows the partial absorption of blue light emitted by the electroluminescence of the blue quantum well layer by the luminescent centers in the first green quantum well layer. After losing some energy through non-radiative relaxation, the absorbed blue photons are re-radiated as longer-wavelength green photons through a photoluminescence mechanism, achieving photoluminescence of green light, thus simultaneously exciting both blue and green wavelengths.

[0015] 2. The first N-type semiconductor layer and the second N-type semiconductor layer together serve as electron supply layers, both providing electrons. Together with the first stress relief layer and the first green quantum well layer, they also play a role in carrier regulation, optimizing the injection efficiency of electrons into the blue quantum well layer, coordinating the electron concentration distribution and electron-hole matching degree in the blue quantum well layer, thereby enhancing the emission intensity of blue light generated by the electroluminescence of the blue quantum well layer. The increased emission intensity of blue light ensures a sufficient number of blue photons available for absorption and utilization by the first green quantum well layer, thus contributing to enhanced emission intensity in the green light band. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a dual-band LED epitaxial wafer according to the present invention; The structure includes: substrate 1, buffer layer 2, first N-type semiconductor layer 3, first stress relief layer 4, first InGaN layer 41, first Si-doped GaN layer 42, first green quantum well layer 5, green InGaN layer 51, green Si-doped GaN layer 52, second N-type semiconductor layer 6, second stress relief layer 7, second InGaN layer 71, second Si-doped GaN layer 72, blue quantum well layer 8, blue InGaN layer 81, blue Si-doped GaN layer 82, P-type semiconductor layer 9, electron blocking layer 10, second green quantum well layer 100, green Mg-doped InGaN layer 1001, green Mg-doped GaN layer 1002, and P-type ohmic contact layer 200. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0018] Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Raw materials whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0019] This invention proposes a dual-band LED epitaxial wafer, comprising a substrate 1, a buffer layer 2, a first N-type semiconductor layer 3, a first stress relief layer 4, a first green quantum well layer 5, a second N-type semiconductor layer 6, a second stress relief layer 7, a blue quantum well layer 8, an electron blocking layer 10, a P-type semiconductor layer 9, a second green quantum well layer 100, and a P-type ohmic contact layer 200, arranged sequentially along the epitaxial direction; The first stress relief layer 4 includes a first InGaN layer 41 and a first Si-doped GaN layer 42 that are periodically and alternately grown along the epitaxial direction. The second stress relief layer 7 includes a second InGaN layer 71 and a second Si-doped GaN layer 72 that are periodically and alternately grown along the epitaxial direction; The first green quantum well layer 5 includes a green InGaN layer 51 and a green Si-doped GaN layer 52 that are periodically and alternately grown along the epitaxial direction. The blue quantum well layer 8 includes a blue InGaN layer 81 and a blue Si-doped GaN layer 82 that are periodically and alternately grown along the epitaxial direction. The second green quantum well layer 100 includes a green Mg-doped InGaN layer 1001 and a green Mg-doped GaN layer 1002 that are periodically and alternately grown along the epitaxial direction. The In composition content of the first InGaN layer 41 is X1, the In composition content of the second InGaN layer 71 is X2, the In composition content of the green InGaN layer 51 is X3, the In composition content of the blue InGaN layer 81 is X4, and the In composition content of the green Mg-doped InGaN layer 1001 is X5, which satisfies X1 < X4 < X3 = X5 and X2 < X4 < X3 = X5.

[0020] When energized, the blue quantum well layer 8 undergoes radiative recombination to generate blue light (electroluminescence). Simultaneously, the second N-type semiconductor layer 6 is rich in electrons, which readily recombine and annihilate with holes, suppressing hole injection into the first green quantum well layer 5. This significantly reduces the possibility of undesirable electroluminescence caused by radiative recombination of electrons and holes within the first green quantum well layer 5. Furthermore, the electron blocking layer 10 effectively suppresses electron injection into the second green quantum well layer 100, thereby inhibiting the possibility of undesirable electroluminescence caused by radiative recombination of electrons and holes within the second green quantum well layer 100.

[0021] Furthermore, some of the blue light emitted by the electroluminescent blue quantum well layer 8 can penetrate the second N-type semiconductor layer 6 and enter the green InGaN layer 51 of the first green quantum well layer 5. Since the In content of the blue InGaN layer 81 is less than that of the green InGaN layer 51, and the bandgap of InGaN is negatively correlated with the In content, the bandgap of the green InGaN layer 51 is smaller than that of the blue InGaN layer 81. This bandgap design allows some of the blue light emitted by the electroluminescent blue quantum well layer 8 to be selectively absorbed by the luminescent centers in the first green quantum well layer 5. After losing some energy through non-radiative relaxation, the absorbed blue photons are re-radiated as longer-wavelength green photons through a photoluminescence mechanism, achieving photoluminescence of green light, thus simultaneously exciting both blue and green wavelengths.

[0022] Furthermore, since the In content of the blue InGaN layer 81 is less than that of the green Mg-doped InGaN layer 1001, and the bandgap of InGaN is negatively correlated with the In content, the bandgap of the green Mg-doped InGaN layer 1001 is smaller than that of the blue InGaN layer 81. This bandgap design allows some of the blue light emitted by the electroluminescent blue quantum well layer 8 to be selectively absorbed by the luminescent centers in the second green quantum well layer 100. The absorbed blue photons, after losing some energy through non-radiative relaxation, are then re-radiated as longer-wavelength green photons through a photoluminescence mechanism, achieving photoluminescence of green light and enhancing the green light intensity.

[0023] The light-emitting mechanism described in this scheme enables the simultaneous excitation of two different light sources, green and blue, achieving dual-band emission through a single epitaxial growth process. This eliminates the need to fabricate chips with different material systems, reducing the complexity and cost of epitaxy and fabrication processes. Furthermore, the light-emitting structure avoids the use of phosphors, fundamentally eliminating the deterioration of color rendering performance caused by phosphor aging and thermal light decay.

[0024] Secondly, the first N-type semiconductor layer 3 and the second N-type semiconductor layer 6 together serve as electron supply layers, each undertaking the function of providing electrons. Together with the first stress relief layer 4 and the first green quantum well layer 5, they also play a role in carrier regulation, optimizing the injection efficiency of electrons into the blue quantum well layer 8, coordinating the electron concentration distribution and the matching degree between electrons and holes in the blue quantum well layer 8, thereby enhancing the emission intensity of blue light generated by the electroluminescence of the blue quantum well layer 8.

[0025] Furthermore, the green Mg-doped InGaN layer 1001 can store some holes, which can improve the hole injection efficiency of the P-type layer. Both the green Mg-doped InGaN layer 1001 and the green Mg-doped GaN layer 1002 are doped with Mg, which can provide some holes to the blue quantum well layer 8 to participate in radiative recombination luminescence, further improving the hole injection efficiency. This improves the hole distribution and electron-hole matching degree in the blue quantum well layer 8, thereby further increasing the blue light emission intensity.

[0026] Limiting the In content of the green Mg-doped InGaN layer 1001 and adopting a green Mg-doped InGaN layer 1001 with a higher In content can improve the hole injection efficiency, which is beneficial to further improve the blue light emission intensity of the blue quantum well layer 8.

[0027] The aforementioned design, which involves the interaction of the first N-type semiconductor layer 3, the second N-type semiconductor layer 6, the green Mg-doped InGaN layer 1001, and the green Mg-doped GaN layer 1002, as well as the design of the In content of the green Mg-doped InGaN layer 1001, is beneficial for improving the emission intensity of blue light. The increased emission intensity of blue light ensures a sufficient number of blue photons available for absorption and utilization by the first green quantum well layer 5, thereby enhancing the emission intensity in the green light band.

[0028] Furthermore, the bandgap of InGaN is negatively correlated with the content of In components: the lower the content of In components, the larger the bandgap and the shorter the corresponding emission wavelength. The In component content of the first InGaN layer 41 and the second InGaN layer 71 are both lower than the In component content of the blue InGaN layer 81, which means that the bandgap of the first InGaN layer 41 and the second InGaN layer 71 is greater than the bandgap of the blue InGaN layer 81. The above bandgap design has the following effects: (1) It effectively suppresses the absorption of some blue light emitted by the blue quantum well layer 8 by the first InGaN layer 41 and the second InGaN layer 71, so that the blue light photons mainly act on the first green quantum well layer 5, thereby improving its photoluminescence intensity; (2) It reduces the risk of yellow light and even red light emission caused by the higher In component content of the first InGaN layer 41 and the second InGaN layer 71 than the In component content of the blue InGaN layer 81, effectively improving the purity of the emission spectrum.

[0029] Finally, the first stress relief layer 4 and the second stress relief layer 7 are both InGaN pre-layers with relatively low In content, and have the following functions: (1) Improve the crystal quality of the subsequent quantum well. The first stress relief layer 4 serves as a buffer layer before the growth of the first green quantum well layer 5, and the second stress relief layer 7 serves as a buffer layer before the growth of the blue quantum well layer 8. The setting of the first stress relief layer 4 can improve the interface flatness between the first green quantum well layer 5 and the first N-type semiconductor layer 3, suppress the extension of defects and dislocations into the active region, and provide a good template for the subsequent high-quality growth of the first green quantum well layer 5; similarly, the second stress relief layer 7 also provides a good template for the high-quality growth of the blue quantum well layer 8; (2) Realize strain gradient transition. It can alleviate the abrupt stress caused by lattice mismatch, reduce the risk of strain relaxation and cracking, and improve the reliability of the epitaxial wafer; (3) Improve the well-barrier interface matching degree. The first stress relief layer 4 can make the band transition between the first N-type semiconductor layer 3 and the first green quantum well layer 5, and the second stress relief layer 7 can make the band transition between the second N-type semiconductor layer 6 and the blue quantum well layer 8 smoother, thereby improving the carrier confinement effect and interface quality and thus improving the luminous efficiency.

[0030] It should be noted that both the first N-type semiconductor layer 3 and the second N-type semiconductor layer 6 are existing N-type semiconductor layers. As an optional example, both the first N-type semiconductor layer 3 and the second N-type semiconductor layer 6 can be made of Si-doped GaN, with a growth thickness of 0.3 μm to 10 μm and a Si doping concentration of 3.2 × 10⁻⁶. 18 / cm 3 ~6.8×10 20 / cm 3 The growth temperature is 900℃~1250℃, and the growth pressure is 30 torr~360 torr.

[0031] The P-type semiconductor layer 9 is a P-type semiconductor layer in the prior art. As an optional example, the P-type semiconductor layer 9 satisfies the following conditions: (1) The material of the P-type semiconductor layer 9 is Mg-doped GaN, and the concentration of Mg doping is 2.5 × 10⁻⁶. 19 / cm 3 ~5.8×10 20 / cm 3 (2) Thickness is 20nm~500nm; (3) Growth temperature is 950℃~1050℃; (4) Growth pressure is 30torr~360torr.

[0032] The electron blocking layer 10 is an electron blocking layer structure in the prior art. As an optional example, the electron blocking layer 10 is formed by periodically alternating growth of an AlGaN layer and a Mg-doped InGaN layer; the period of alternating growth ranges from 2 to 20; the AlGaN layer satisfies the following conditions: (1) no doping; (2) the content of Al component is 0.2 to 1; (3) the growth thickness is 0.2 nm to 3.6 nm; (4) the growth temperature is 720℃ to 1050℃; (5) the growth pressure is 30 torr to 360 torr; the Mg-doped InGaN layer satisfies the following conditions: (1) the doping concentration of Mg is 1.5 × 10⁻⁶. 18 / cm 3 ~6.8×10 19 / cm 3 (2) The content of In component is 0.02 to 0.15; (3) The growth thickness is 0.2 nm to 3.6 nm; (4) The growth temperature is 720℃ to 1050℃; (5) The growth pressure is 30 torr to 360 torr.

[0033] The P-type ohmic contact layer 200 is a P-type ohmic contact layer in the prior art. As an optional example, the P-type ohmic contact layer 200 satisfies the following conditions: (1) The material of the P-type ohmic contact layer 200 is Mg-doped AlInGaN, and the Mg doping concentration is 3×10⁻⁶. 19 / cm 3 ~5×10 21 / cm 3 , Al content > 0 and ≤ 0.15, In content > 0 and ≤ 0.5; (2) Thickness is 0.2nm to 30nm; (3) Growth temperature is 950℃ to 1050℃; (4) Growth pressure is 30torr to 360torr.

[0034] Preferably, the number of alternating growth cycles of the first stress relief layer 4 is 2 to 9; And / or, the number of alternating growth cycles of the second stress-relieving layer 7 is 2 to 9; And / or, the number of alternating growth cycles of the first green quantum well layer 5 is 1 to 12; And / or, the number of alternating growth cycles of the blue quantum well layer 8 is 2 to 15; And / or, the number of growth cycles of the second green quantum well layer 100 is 2 to 15.

[0035] For example, the number of alternating growth cycles of the first stress-relief layer 4 includes, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, or any two of the above values. The number of alternating growth cycles of the second stress-relief layer 7 includes, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, or any two of the above values. The number of alternating growth cycles of the first green quantum well layer 5 includes, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or any two of the above values. The number of alternating growth cycles of the blue quantum well layer 8 includes, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or any two of the above values. The number of growth cycles of the second green quantum well layer 100 includes, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or any two of the above values.

[0036] Substrate 1 may be a silicon substrate, a silicon carbide substrate, a sapphire substrate, a gallium nitride substrate, or a zinc oxide substrate, but is not limited to these.

[0037] In some embodiments, the difference between X4 and X1 ranges from 0.03 to 0.17; And / or, the difference between X4 and X2 ranges from 0.03 to 0.17; And / or, the difference between X3 and X4 is in the range of 0.03 to 0.23.

[0038] The aforementioned limitations are more conducive to enhancing the emission intensity, luminous efficiency, and luminous purity of the green light band. For example, the difference range between X4 and X1, and between X4 and X2, includes, but is not limited to, 0.03, 0.06, 0.09, 0.12, 0.15, 0.17, or any interval formed by any two of the above values. The difference range between X3 and X4 includes, but is not limited to, 0.03, 0.06, 0.09, 0.12, 0.15, 0.18, 0.21, 0.23, or any interval formed by any two of the above values.

[0039] In some embodiments, the first InGaN layer 41 satisfies the following condition: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1050℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the first Si-doped GaN layer 42 satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1080℃; (4) The growth pressure is 30 torr to 360 torr.

[0040] The above configuration allows the first stress-relieving layer 4 to better perform its functions of improving luminescence purity, enhancing the crystal quality of subsequent quantum wells, improving epitaxial wafer reliability, and increasing luminescence efficiency. For example, the In content of the first InGaN layer 41 includes, but is not limited to, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, or any two of the above values. The growth thickness of the first InGaN layer 41 includes, but is not limited to, 0.6 nm, 1 nm, 2 nm, 3 nm, 4 nm, or any two of the above values. The growth temperature of the first InGaN layer 41 includes, but is not limited to, 720℃, 750℃, 800℃, 850℃, 950℃, 1000℃, 1050℃, or any two of the above values. The growth pressure of the first InGaN layer 41 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values ​​within a range.

[0041] The Si doping concentration in the first Si-doped GaN layer 42 includes, but is not limited to, 1.2 × 10⁻⁶. 17 / cm 3 5×10 17 / cm 3 1×10 18 / cm 3 6.8×10 18 / cm 3The growth thickness of the first Si-doped GaN layer 42 includes, but is not limited to, 1.2 nm, 5 nm, 10 nm, 15 nm, 20 nm, or any two of the above values. The growth temperature of the first Si-doped GaN layer 42 includes, but is not limited to, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1080℃, or any two of the above values. The growth pressure of the first Si-doped GaN layer 42 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values.

[0042] In some embodiments, the second InGaN layer 71 satisfies the following condition: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the second Si-doped GaN layer 72 satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1020℃; (4) The growth pressure is 30 torr to 360 torr.

[0043] The above configuration allows the second stress-relieving layer 7 to better perform its functions of improving luminescence purity, enhancing the crystal quality of subsequent quantum wells, improving epitaxial wafer reliability, and increasing luminescence efficiency. For example, the In content of the second InGaN layer 71 includes, but is not limited to, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, or any two of the above values. The growth thickness of the second InGaN layer 71 includes, but is not limited to, 0.6 nm, 1 nm, 2 nm, 3 nm, 4 nm, or any two of the above values. The growth temperature of the second InGaN layer 71 includes, but is not limited to, 720℃, 750℃, 800℃, 850℃, 950℃, 1000℃, or any two of the above values. The growth pressure of the second InGaN layer 71 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values ​​within a range.

[0044] The Si doping concentration in the second Si-doped GaN layer 72 includes, but is not limited to, 1.2 × 10⁻⁶. 17 / cm 3 5×10 17 / cm 3 1×10 18 / cm 3 6.8×10 18 / cm 3 The growth thickness of the second Si-doped GaN layer 72 is, but is not limited to, 1.2 nm, 5 nm, 10 nm, 15 nm, 20 nm, or any two of the above values ​​within a range. The growth temperature of the second Si-doped GaN layer 72 is, but is not limited to, 800℃, 850℃, 900℃, 950℃, 1000℃, 1020℃, or any two of the above values ​​within a range. The growth pressure of the second Si-doped GaN layer 72 is, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values ​​within a range.

[0045] In some embodiments, the green InGaN layer 51 satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 1 nm to 6 nm; (4) The growth temperature is 650℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Si-doped GaN layer 52 satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 3nm to 30nm; (3) The growth temperature is 800℃~1050℃; (4) The growth pressure is 30 torr to 360 torr.

[0046] The above configuration enables the first green quantum well layer 5 to effectively absorb blue light and efficiently emit green light, thereby improving its green light emission intensity. For example, the In content in the green InGaN layer 51 includes, but is not limited to, 0.22, 0.24, 0.26, 0.28, or any two of the above values ​​within a range. The growth thickness of the green InGaN layer 51 includes, but is not limited to, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, or any two of the above values ​​within a range. The growth temperature of the green InGaN layer 51 includes, but is not limited to, 650℃, 700℃, 750℃, 800℃, 850℃, 950℃, 1000℃, or any two of the above values ​​within a range. The growth pressure of the green InGaN layer 51 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values ​​within a range.

[0047] The Si doping concentration in the green Si-doped GaN layer 52 includes, but is not limited to, 1.2 × 10⁻⁶. 17 / cm 3 5×10 17 / cm 3 1×10 18 / cm 3 6.8×10 18 / cm 3 The growth thickness of the green Si-doped GaN layer 52 includes, but is not limited to, 3nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, or any two of the above values. The growth temperature of the green Si-doped GaN layer 52 includes, but is not limited to, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, or any two of the above values. The growth pressure of the green Si-doped GaN layer 52 includes, but is not limited to, 30torr, 90torr, 150torr, 210torr, 270torr, 330torr, 360torr, or any two of the above values.

[0048] In some embodiments, the blue InGaN layer 81 satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.05-0.19; (3) The growth thickness is 2nm to 5nm; (4) The growth temperature is 720℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the blue light Si-doped GaN layer 82 satisfies the following condition: (1) The doping concentration of Si is 1.5 × 10⁻⁶. 17 / cm 3 ~8.6×10 17 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 760℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

[0049] For example, the In content of the blue InGaN layer 81 includes, but is not limited to, 0.05, 0.1, 0.15, 0.19, or any two of the above values. The growth thickness of the blue InGaN layer 81 includes, but is not limited to, 2 nm, 3 nm, 4 nm, 5 nm, or any two of the above values. The growth temperature of the blue InGaN layer 81 includes, but is not limited to, 720°C, 750°C, 800°C, 850°C, 900°C, 930°C, or any two of the above values. The growth pressure of the blue InGaN layer 81 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values.

[0050] The Si doping concentration in the blue light Si-doped GaN layer 82 includes, but is not limited to, 1.5 × 10⁻⁶. 17 / cm 3 3×10 17 / cm 3 4.5×10 17 / cm 3 6×10 17 / cm 3 8.6×10 17 / cm 3The growth thickness of the blue Si-doped GaN layer 82 includes, but is not limited to, 5 nm, 10 nm, 15 nm, or any two of the above values. The growth temperature of the blue Si-doped GaN layer 82 includes, but is not limited to, 760℃, 800℃, 850℃, 900℃, 950℃, or any two of the above values. The growth pressure of the blue Si-doped GaN layer 82 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values.

[0051] In some embodiments, the green Mg-doped InGaN layer 1001 satisfies the following conditions: (1) The doping concentration of Mg is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 2.1 nm to 4.8 nm; (4) The growth temperature is 680℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Mg-doped GaN layer 1002 satisfies the following conditions: (1) The Mg doping concentration is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 780℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

[0052] The above configuration allows the green Mg-doped InGaN layer 1001 to store some holes, improving the hole injection efficiency of the P-type layer. Furthermore, both the green Mg-doped InGaN layer 1001 and the green Mg-doped GaN layer 1002 are doped with Mg, which can provide some holes to the blue quantum well layer 8 to participate in radiative recombination luminescence, further improving the hole injection efficiency. This improves the hole distribution and electron-hole matching degree in the blue quantum well layer 8, thereby increasing luminous efficiency and blue light emission intensity. For example, the Mg doping concentration in the green Mg-doped InGaN layer 1001 may include, but is not limited to, 3.5 × 10⁻⁶. 17 / cm 35×10 17 / cm 3 1×10 18 / cm 3 5×10 18 / cm 3 1×10 19 / cm 3 6.8×10 19 / cm 3 The In content of the green Mg-doped InGaN layer 1001 is, but is not limited to, 0.22, 0.24, 0.26, 0.28, or any two of the above values ​​within a range. The growth thickness of the green Mg-doped InGaN layer 1001 is, but is not limited to, 2.1 nm, 3 nm, 4 nm, 4.8 nm, or any two of the above values ​​within a range. The growth temperature of the green Mg-doped InGaN layer 1001 is, but is not limited to, 680℃, 700℃, 750℃, 800℃, 850℃, 900℃, 930℃, or any two of the above values ​​within a range. The growth pressure of the green Mg-doped InGaN layer 1001 is, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values ​​within a range.

[0053] The Mg doping concentration in the green Mg-doped GaN layer 1002 includes, but is not limited to, 3.5 × 10⁻⁶. 17 / cm 3 5×10 17 / cm 3 1×10 18 / cm 3 5×10 18 / cm 3 1×10 19 / cm 3 6.8×10 19 / cm 3 The growth thickness of the green Mg-doped GaN layer 1002 includes, but is not limited to, 5 nm, 10 nm, 15 nm, or any two of the above values. The growth temperature of the green Mg-doped GaN layer 1002 includes, but is not limited to, 780℃, 800℃, 850℃, 900℃, 950℃, or any two of the above values. The growth pressure of the green Mg-doped GaN layer 1002 includes, but is not limited to, 30 torr, 90 torr, 150 torr, 210 torr, 270 torr, 330 torr, 360 torr, or any two of the above values.

[0054] This invention also proposes a method for fabricating a dual-band LED epitaxial wafer, used to fabricate the dual-band LED epitaxial wafer as described above, comprising: A buffer layer 2 is grown on substrate 1; A first N-type semiconductor layer 3 is grown on buffer layer 2; A first stress relief layer 4 is grown on the first N-type semiconductor layer 3; A first green quantum well layer 5 is grown on the first stress relief layer 4; A second N-type semiconductor layer 6 is grown on the first green quantum well layer 5; A second stress-relieving layer 7 is grown on the second N-type semiconductor layer 6; A blue quantum well layer 8 is grown on the second stress-relieving layer 7; An electron blocking layer 10 is grown on the blue quantum well layer 8. A P-type semiconductor layer 9 is grown on the electron blocking layer 10. A second green quantum well layer 100 is grown on the P-type semiconductor layer 9; A P-type ohmic contact layer 200 is grown on the second green quantum well layer 100 to obtain a dual-band LED epitaxial wafer.

[0055] This invention also proposes a method for preparing a blue-green dual-band LED epitaxial wafer. The method is simple and, while reducing the use of phosphors and manufacturing costs, not only improves color rendering performance and green light enhancement performance, but also increases luminous efficiency. It should be noted that the growth processes of the substrate 1, buffer layer 2, first N-type semiconductor layer 3, first stress relief layer 4, first green quantum well layer 5, second N-type semiconductor layer 6, second stress relief layer 7, blue quantum well layer 8, electron blocking layer 10, P-type semiconductor layer 9, second green quantum well layer 100, and P-type ohmic contact layer 200 are all conventional processes in the prior art, and will not be elaborated upon here.

[0056] The technical solution of the present invention will be further described below through embodiments and comparative examples.

[0057] Example 1 This embodiment provides a blue-green dual-band LED epitaxial wafer, comprising a sapphire substrate 1, a buffer layer 2, a first N-type semiconductor layer 3, a first stress relief layer 4, a first green quantum well layer 5, a second N-type semiconductor layer 6, a second stress relief layer 7, a blue quantum well layer 8, an electron blocking layer 10, a P-type semiconductor layer 9, a second green quantum well layer 100, and a P-type ohmic contact layer 200, arranged sequentially along the epitaxial direction. The first stress relief layer 4 comprises a first InGaN layer 41 and a first Si-doped GaN layer 42 that are periodically and alternately grown along the epitaxial direction; the number of alternating growth cycles of the first stress relief layer 4 is 6; the first InGaN layer 41 is undoped; the In content is 0.09%; the growth thickness is 2 nm; the growth temperature is 900 °C; the growth pressure is 180 torr; and the Si doping concentration of the first Si-doped GaN layer 42 is 3 × 10⁻⁶. 18 / cm 3 The growth thickness was 10 nm; the growth temperature was 940℃; and the growth pressure was 180 torr. The first green quantum well layer 5 comprises a green InGaN layer 51 and a green Si-doped GaN layer 52 that are periodically and alternately grown along the epitaxial direction; the number of alternating growth periods of the first green quantum well layer 5 is 6; the green InGaN layer 51 is undoped; the In content is 0.26%; the growth thickness is 3 nm; the growth temperature is 850 °C; the growth pressure is 180 torr; and the Si doping concentration of the green Si-doped GaN layer 52 is 3 × 10⁻⁶. 18 / cm 3 The growth thickness was 15 nm; the growth temperature was 920℃; and the growth pressure was 180 torr. The second stress relief layer 7 comprises a second InGaN layer 71 and a second Si-doped GaN layer 72 that are periodically and alternately grown along the epitaxial direction; the number of alternating growth periods of the second stress relief layer 7 is 5; the second InGaN layer 71 is undoped; the In content is 0.1%; the growth thickness is 2 nm; the growth temperature is 850 °C; the growth pressure is 190 torr; and the Si doping concentration of the second Si-doped GaN layer 72 is 3 × 10⁻⁶. 18 / cm 3 The growth thickness was 10 nm; the growth temperature was 870℃; and the growth pressure was 170 torr. The blue quantum well layer 8 comprises a blue InGaN layer 81 and a blue Si-doped GaN layer 82 that are periodically and alternately grown along the epitaxial direction; the number of alternating growth periods of the blue quantum well layer 8 is 9; the blue InGaN layer 81 is undoped; the In content is 0.14%; the growth thickness is 3 nm; the growth temperature is 820 °C; the growth pressure is 160 torr; and the Si doping concentration of the blue Si-doped GaN layer 82 is 4 × 10⁻⁶. 17 / cm 3 The growth thickness was 10 nm; the growth temperature was 850℃; and the growth pressure was 180 torr. The second green quantum well layer 100 includes a green Mg-doped InGaN layer 1001 and a green Mg-doped GaN layer 1002 that are periodically and alternately grown along the epitaxial direction; the number of growth cycles of the second green quantum well layer 100 is 9; the Mg doping concentration of the green Mg-doped InGaN layer 1001 is 5 × 10⁻⁶. 18 / cm 3 The In content was 0.26%; the growth thickness was 3.4 nm; the growth temperature was 810℃; the growth pressure was 180 torr; and the Mg doping concentration of the green Mg-doped GaN layer 1002 was 5 × 10⁻⁶. 18 / cm 3 The growth thickness was 10 nm; the growth temperature was 870℃; and the growth pressure was 180 torr. The first N-type semiconductor layer 3 and the second N-type semiconductor layer 6 are both made of Si-doped GaN, with a growth thickness of 5 μm and a Si doping concentration of 6 × 10⁻⁶. 19 / cm 3 The growth temperature was 1050℃, and the growth pressure was 165 torr; The material of the p-type semiconductor layer 9 is Mg-doped GaN, and the Mg doping concentration is 1×10⁻⁶. 20 / cm 3 Thickness: 300 nm; Growth temperature: 1000℃; Growth pressure: 150 torr; The electron blocking layer 10 is formed by periodically alternating AlGaN layers and Mg-doped InGaN layers; the number of alternating growth cycles is 5; the AlGaN layer is undoped; the Al content is 0.6%; the growth thickness is 3 nm; the growth temperature is 900 °C; the growth pressure is 140 torr; and the Mg doping concentration in the Mg-doped InGaN layer is 1 × 10⁻⁶. 19 / cm 3 The In content was 0.08; the growth thickness was 2 nm; the growth temperature was 880℃; and the growth pressure was 130 torr.

[0058] The P-type ohmic contact layer 200 is made of Mg-doped AlInGaN with a Mg doping concentration of 5 × 10⁻⁶. 20 / cm 3 The content of Al component is 0.1%, the content of In component is 0.2%, the thickness is 15nm, the growth temperature is 980℃, and the growth pressure is 160torr.

[0059] Example 2-Example 3 Examples 2 and 3 are based on Example 1, but differ from Example 1 in that the parameters of the first stress-relieving layer 4 in Examples 2 and 3 are different from those in Example 1. Specific experimental parameters are shown in Table 1.

[0060] Examples 4-5 Examples 4 and 5 are based on Example 1, but differ from Example 1 in that the parameters of the second stress-relieving layer 7 in Examples 4 and 5 are different from those in Example 1. Specific experimental parameters are shown in Table 1.

[0061] Examples 6-7 Examples 6-7 refer to Example 1. The difference between Examples 6-7 and Example 1 lies in the parameters of the second green quantum well layer 100 and the In content of the green InGaN layer 51. Specifically, the In content of the green InGaN layer 51 in Example 6 is 0.22, while the In content of the green InGaN layer 51 in Example 7 is 0.28. The parameters of the second green quantum well layer 100 in Examples 6-7 are shown in Table 1.

[0062] Comparative Example 1 Comparative Example 1 refers to Example 1. The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 lacks the first stress relief layer 4, the second N-type semiconductor layer 6, the second stress relief layer 7, and the second green light quantum well layer 100.

[0063] Comparative Example 2 Comparative Example 2 is the same as Example 1. The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 lacks the second N-type semiconductor layer 6 and the second green quantum well layer 100.

[0064] Comparative Example 3 Comparative Example 3 refers to Example 1. The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 lacks the first stress relief layer 4 and the second green light quantum well layer 100.

[0065] Comparative Example 4 Comparative Example 4 refers to Example 1. The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 lacks the second stress relief layer 7 and the second green light quantum well layer 100.

[0066] Comparative Example 5 Comparative Example 5 refers to Example 1. The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 lacks the second green light quantum well layer 100.

[0067] Comparative Example 6 Comparative Example 6 refers to Example 1. The difference between Comparative Example 6 and Example 1 is that Comparative Example 6 lacks the first green quantum well layer 5.

[0068] Table 1. Experimental parameters in the LED epitaxial wafer fabrication process of Examples 1-7

[0069] The performance of the blue-green dual-band LED epitaxial wafers obtained in the examples and comparative examples was tested, and the specific testing methods are as follows: Luminous efficiency improvement performance: The epitaxial wafer is fabricated into a 20μm×20μm LED chip, and the luminous efficiency is improved at 20A / cm. 2 The chip's luminous efficacy was improved under the tested operating current density. The improvement in luminous efficacy was calculated based on Comparative Example 1.

[0070] Color rendering index (Ra): When an epitaxial wafer is fabricated into a 20μm × 20μm LED chip, the color rendering index is measured at 20 A / cm². 2 The chip was lit up at the operating current density, and its emission spectrum was measured using a spectroradiometer. The general color rendering index Ra was calculated according to CIE 13.3-1995. The evaluation criteria were: Ra ≥ 80 for good color rendering, Ra ≥ 95 for excellent color rendering, and Ra < 80 for poor color rendering.

[0071] Fidelity Index (Rf): The emission spectrum of the chip is measured using a spectroradiometer. The Rf index is calculated according to the IES TM-30-15 standard. This index characterizes the overall performance of the light source in terms of color fidelity to the standard color sample. The evaluation criteria are: Rf ≥ 80 indicates good fidelity, Rf ≥ 95 indicates excellent fidelity, and Rf < 80 indicates insufficient fidelity and significant color distortion.

[0072] Green light emission intensity: An epitaxial wafer was fabricated into a 20μm × 20μm LED chip, and under the same driving current (20A / cm²), the green light emission intensity was measured. 2 The emission (EL) spectrum of the chip was measured using a spectroradiometer. The emission peak intensity in the green light band (500–560 nm) and its integral area ratio in the total visible light spectrum (380–780 nm) were recorded (i.e., the green light ratio). At the same time, based on the green light ratio of Comparative Example 1, the relative increase percentage of the green light ratio in the embodiment of the present invention was calculated to evaluate the green light enhancement effect.

[0073] Table 2 Test Results of Dual-Band LED Epitaxial Wafers

[0074] As shown in Table 2, the dual-band LED epitaxial wafers obtained in Examples 1-7 have a luminous efficiency improvement of >3.4%, a color rendering index of >85, a fidelity index of >83, and a green light emission intensity of >60%. This technical solution is beneficial for improving not only color rendering performance and green light enhancement performance, but also luminous efficiency, while reducing the use of phosphors and lowering manufacturing costs.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A dual-band LED epitaxial wafer, characterized in that, It includes a substrate, a buffer layer, a first N-type semiconductor layer, a first stress relief layer, a first green quantum well layer, a second N-type semiconductor layer, a second stress relief layer, a blue quantum well layer, an electron blocking layer, a P-type semiconductor layer, a second green quantum well layer, and a P-type ohmic contact layer, which are sequentially arranged along the epitaxial direction. The first stress relief layer includes a first InGaN layer and a first Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction; The second stress relief layer includes a second InGaN layer and a second Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction; The first green quantum well layer includes a green InGaN layer and a green Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The blue quantum well layer includes a blue InGaN layer and a blue Si-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The second green quantum well layer includes a green Mg-doped InGaN layer and a green Mg-doped GaN layer that are periodically and alternately grown along the epitaxial direction. The In composition content of the first InGaN layer is X1, the In composition content of the second InGaN layer is X2, the In composition content of the green InGaN layer is X3, the In composition content of the blue InGaN layer is X4, and the In composition content of the green Mg-doped InGaN layer is X5, which satisfies X1 < X4 < X3 = X5 and X2 < X4 < X3 = X5.

2. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The difference between X4 and X1 ranges from 0.03 to 0.17; And / or, the difference between X4 and X2 ranges from 0.03 to 0.17; And / or, the difference between X3 and X4 is in the range of 0.03 to 0.

23.

3. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The first InGaN layer satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1050℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the first Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1080℃; (4) The growth pressure is 30 torr to 360 torr.

4. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The second InGaN layer satisfies the following condition: (1) No doping was performed; (2) The content of In component is 0.02-0.16; (3) The growth thickness is 0.6 nm to 4 nm; (4) The growth temperature is 720℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the second Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 1.2 nm to 20 nm; (3) The growth temperature is 800℃~1020℃; (4) The growth pressure is 30 torr to 360 torr.

5. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The green InGaN layer satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 1 nm to 6 nm; (4) The growth temperature is 650℃~1000℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.2 × 10⁻⁶. 17 / cm 3 ~6.8×10 18 / cm 3 ; (2) The growth thickness is 3nm to 30nm; (3) The growth temperature is 800℃~1050℃; (4) The growth pressure is 30 torr to 360 torr.

6. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The blue light InGaN layer satisfies the following conditions: (1) No doping was performed; (2) The content of In component is 0.05-0.19; (3) The growth thickness is 2nm to 5nm; (4) The growth temperature is 720℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the blue light Si-doped GaN layer satisfies the following condition: (1) The doping concentration of Si is 1.5 × 10⁻⁶. 17 / cm 3 ~8.6×10 17 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 760℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

7. The dual-band LED epitaxial wafer according to claim 1, characterized in that, The green Mg-doped InGaN layer satisfies the following conditions: (1) The doping concentration of Mg is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The content of In component is 0.22-0.28; (3) The growth thickness is 2.1 nm to 4.8 nm; (4) The growth temperature is 680℃~930℃; (5) Growth pressure is 30 torr to 360 torr; And / or, the green Mg-doped GaN layer satisfies the following condition: (1) The Mg doping concentration is 3.5 × 10⁻⁶. 17 / cm 3 ~6.8×10 19 / cm 3 ; (2) The growth thickness is 5nm to 15nm; (3) The growth temperature is 780℃~950℃; (4) The growth pressure is 30 torr to 360 torr.

8. A method for fabricating a dual-band LED epitaxial wafer, characterized in that, For fabricating a dual-band LED epitaxial wafer as described in any one of claims 1 to 7, comprising: A buffer layer is grown on the substrate; A first N-type semiconductor layer is grown on the buffer layer; A first stress-relieving layer is grown on the first N-type semiconductor layer; A first green quantum well layer is grown on the first stress-relieving layer; A second N-type semiconductor layer is grown on the first green quantum well layer; A second stress-relieving layer is grown on the second N-type semiconductor layer; A blue quantum well layer is grown on the second stress-relieving layer; An electron blocking layer is grown on the blue quantum well layer. A P-type semiconductor layer is grown on an electron blocking layer. A second green quantum well layer is grown on a P-type semiconductor layer; A P-type ohmic contact layer was grown on the second green quantum well layer to obtain a dual-band LED epitaxial wafer.

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