Blue-green dual-band light emitting diode epitaxial wafer and preparation method thereof

Abstract

The invention relates to a blue-green dual-band light-emitting diode epitaxial wafer which comprises a substrate, a buffer layer, an N-type semiconductor layer, a low-temperature stress release layer, a multi-quantum well light-emitting layer, an electron blocking layer and a P-type semiconductor layer which are sequentially stacked in the epitaxial direction. The multi-quantum light-emitting layer comprises a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer and a second blue light barrier layer which are sequentially, periodically and alternately grown in the epitaxial direction. The first green light barrier layer comprises a pre-well low-energy-level barrier layer, a pre-well high-energy-level barrier layer and a pre-well polarization compensation barrier layer which are sequentially grown along the epitaxial direction; the second green light barrier layer comprises a post-well polarization compensation barrier layer, a post-well high-energy-level barrier layer and a post-well low-energy-level barrier layer which are sequentially grown along the epitaxial direction; the preparation cost of the backlight source can be effectively reduced, the use of fluorescent powder is reduced, the luminous efficiency is high, and the color rendering performance is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, in particular to a blue-green dual-band light emitting diode epitaxial wafer and a preparation method thereof. BACKGROUND

[0002] Light Emitting Diode, abbreviated as LED, as a new type of energy-saving and environment-friendly light source, has attracted great attention in recent years, and many countries regard semiconductor lighting related to LED as a strategic technology.

[0003] The LED backlight light source applied to the display screen has two types of RGB-LED and white light LED, wherein the RGB-LED is packaged by three single-color LED chips of blue, green and red, and the white light LED is formed by combining single-color LED chips with fluorescent powder, for example, combining single-color blue chips with green and red fluorescent powder, or combining single blue LED chips with yellow fluorescent powder. Among them, the display effect of RGB three-primary color LED backlight light source is the best, but the cost is higher, and the white light LED needs to use fluorescent powder, but the color gamut of different fluorescent powder schemes has obvious differences, and the uniformity of the mixture of fluorescent powder and glue is also difficult to control, which can cause problems such as poor light uniformity, poor color consistency, easy deviation of color temperature, and not ideal color rendering performance. SUMMARY

[0004] The present application provides a blue-green dual-band light emitting diode epitaxial wafer and a preparation method thereof, which can effectively reduce the preparation cost of the backlight light source, reduce the use of fluorescent powder, have high light emitting efficiency, and have good color rendering performance.

[0005] In order to solve the above problems, the present application provides a blue-green dual-band light emitting diode epitaxial wafer, which comprises a substrate, a buffer layer, an N-type semiconductor layer, a low-temperature stress release layer, a multi-quantum well light emitting layer, an electron blocking layer and a P-type semiconductor layer which are sequentially stacked along the epitaxial direction. The multi-quantum light emitting layer comprises a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer and a second blue light barrier layer which are alternately grown periodically along the epitaxial direction. The first green light barrier layer comprises a pre-well low-energy barrier layer, a pre-well high-energy barrier layer and a pre-well polarization compensation barrier layer which are sequentially grown along the epitaxial direction. The second green light barrier layer comprises a post-well polarization compensation barrier layer, a post-well high-energy barrier layer and a post-well low-energy barrier layer which are sequentially grown along the epitaxial direction. Among them, H2 atmosphere heat treatment is needed before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy barrier layer.

[0006] As the improvement of the above technical scheme, the growth cycle number of the multi-quantum well light-emitting layer is 2-7; The first blue light InGaN layer has a light-emitting wavelength of 391nm-487nm; The first green light InGaN layer has a light-emitting wavelength of 511nm-565nm; The second blue light InGaN layer has a light-emitting wavelength of 391nm-487nm.

[0007] As the improvement of the above technical scheme, the pre-well low-energy barrier layer and the post-well low-energy barrier layer are both made of Si-doped GaN material, the Si doping concentration is both 1.2×10 17 / cm³-8.7×10 17 / cm³, the growth thickness is both 1nm-9nm, the growth temperature is both 720℃-980℃, and the growth pressure is both 30torr-360torr; The pre-well high-energy barrier layer and the post-well high-energy barrier layer are both made of AlGaN material without intentional doping, the content of Al component is both less than or equal to 0.5, the growth thickness is both 0.2nm-3nm, the growth temperature is both 720℃-980℃, and the growth pressure is both 30torr-360torr; The pre-well polarization compensation barrier layer and the post-well polarization compensation barrier layer are both made of AlGaInN material without intentional doping, the content of Al component is both less than or equal to 0.5, the content of In component is both less than or equal to 0.28, the growth thickness is both 0.2nm-3nm, the growth temperature is both 720℃-980℃, and the growth pressure is both 30torr-360torr.

[0008] As the improvement of the above technical scheme, before depositing the pre-well high-energy barrier layer, and before depositing the post-well high-energy barrier, it further includes heat treatment in H2 atmosphere, the treatment time is 5s-180s, the treatment temperature is 800℃-1030℃, and the treatment pressure is 30torr-360torr.

[0009] As the improvement of the above technical scheme, before depositing the pre-well high-energy barrier layer, H2 atmosphere heat treatment is performed, the treatment time is t1, and the treatment temperature is W1; Before depositing the post-well high-energy barrier layer, H2 atmosphere heat treatment is performed, the treatment time is t2, and the treatment temperature is W2; Wherein, t1>t2, and W1>W2.

[0010] As the improvement of the above technical scheme, the first blue light InGaN layer is a single layer or a multi-layer structure made of InGaN material without intentional doping, the content of In component is X1, 0.05≤X1≤0.19, the growth thickness is H1, H1 is 2.1nm~4.9nm, the growth temperature is 720℃~880℃, and the growth pressure is 30torr~360torr; The first green light InGaN layer is a single layer or a multi-layer structure made of InGaN material without intentional doping, the content of In component is X2, 0.22≤X2≤0.28, the growth thickness is H2, H2 is 2.0nm~4.8nm, the growth temperature is 680℃~880℃, and the growth pressure is 30torr~360torr; The second blue light InGaN layer is a single layer or a multi-layer structure made of InGaN material without intentional doping, the content of In component is X3, 0.05≤X3≤0.19, the growth thickness is H3, H3 is 2.1nm~4.9nm, the growth temperature is 720℃~880℃, and the growth pressure is 30torr~360torr As the improvement of the above technical scheme, the content of In component of the first blue light InGaN layer, the first green light InGaN layer and the second blue light InGaN layer satisfies X2>X1=X3; The growth thickness of the first blue light InGaN layer, the first green light InGaN layer and the second blue light InGaN layer satisfies H2<H1=H3.

[0011] As the improvement of the above technical scheme, the first blue light barrier layer is a single layer or a multi-layer structure, which comprises a first GaN layer and / or a first AlGaN layer, the growth thickness is 6.2nm~15.9nm, the growth temperature is 720℃~980℃, and the growth pressure is 30torr~360torr; The first GaN layer is doped with Si element, the Si doping concentration is 1.5×10 17 / cm³~9.6×10 17 / cm³; The Al component content of the first AlGaN layer is Y1, Y1≤0.65; The second blue light barrier layer is a single layer or a multi-layer structure, which comprises a second GaN layer and / or a second AlGaN layer, the growth thickness is 5.8nm~15.3nm, the growth temperature is 720℃~980℃, and the growth pressure is 30torr~360torr; The second GaN layer is doped with Si element, the Si doping concentration is 1.5×10 17 / cm³~9.6×10 17 / cm³; The Al component content of the second AlGaN layer is Y2, where Y2≤0.35.

[0012] Accordingly, the present invention also provides a method for fabricating a blue-green dual-band light-emitting diode epitaxial wafer, comprising the following steps: Provide a substrate; A buffer layer is deposited on the substrate; An N-type semiconductor layer is deposited on the buffer layer; A low-temperature stress relief layer is deposited on the N-type semiconductor layer; A multi-quantum-well light-emitting layer is deposited on the low-temperature stress-relieving layer; An electron blocking layer is deposited on the multi-quantum-well light-emitting layer; A P-type semiconductor layer is deposited on the electron blocking layer; The multi-quantum light-emitting layer includes a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer, and a second blue light barrier layer that are periodically and alternately grown along the epitaxial direction. The first green light barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction. The second green light barrier layer includes a back-well polarization compensation barrier layer, a back-well high-level barrier layer, and a back-well low-level barrier layer that grow sequentially along the epitaxial direction. Specifically, H2 atmosphere heat treatment is required before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy barrier layer.

[0013] As an improvement to the above technical solution, the number of growth cycles of the multi-quantum-well light-emitting layer is 2 to 7; The emission wavelength of the first blue InGaN layer is 391nm~487nm; The emission wavelength of the second green InGaN layer is 511nm~565nm; The emission wavelength of the third blue InGaN layer is 391nm~487nm; Before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy layer, the process includes heat treatment in an H2 atmosphere for 5 s to 180 s, at a temperature of 800 ℃ to 1030 ℃, and at a pressure of 30 torr to 360 torr.

[0014] The implementation of this invention has the following beneficial effects: (1) This invention provides a blue-green dual-band light-emitting diode epitaxial wafer, wherein the multi-quantum-well light-emitting layer in the epitaxial wafer includes a first blue InGaN layer, a first blue barrier layer, a first green barrier layer, a first green InGaN layer, a second green barrier layer, a second blue InGaN layer, and a second blue barrier layer, which are periodically and alternately grown along the epitaxial direction. That is, the light-emitting diode prepared from this epitaxial wafer can excite a light source in a blue light band and a light source in a green light band, thereby reducing the cost of RGB-LED backlight source and reducing the use of phosphor in white LED backlight source.

[0015] (2) The first green barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction; the second green barrier layer includes a polarization compensation barrier layer behind the well, a high-level barrier layer behind the well, and a low-level barrier layer behind the well, which are grown sequentially along the epitaxial direction; wherein, heat treatment in H2 atmosphere is required before depositing the high-level barrier layer in front of the well and before depositing the high-level barrier layer behind the well. After this treatment, the surface of the epitaxial layer material will form a rough material surface, on which atomic deposition can be performed. The surface of the epitaxial layer material is filled, which can reduce the interface of the first green InGaN layer to be smoother and reduce the defect density. It can bind the charge carriers in the first green InGaN layer to generate radiative recombination luminescence, improve the luminescence efficiency, and effectively prevent electron leakage caused by electron overflow.

[0016] (3) The setting of the pre-well polarization compensation barrier layer and the post-well polarization compensation barrier layer allows the energy band to be affected by the spontaneous polarization electric field and the piezoelectric polarization electric field. The spontaneous polarization electric field is opposite in direction to the applied electric field, and the influence of the spontaneous polarization electric field of the first green InGaN layer can be offset by increasing the applied electric field. Furthermore, the intensity of the piezoelectric polarization electric field of the first green InGaN layer can be controlled, so that the difference in polarization electric field intensity of the first blue InGaN layer, the first green InGaN layer, and the second blue InGaN layer is reduced, and the wavelength shift amplitude is more consistent under different current densities, which effectively improves the stability of the intensity ratio of light in each band and improves the luminous efficiency. Attached Figure Description

[0017] Fig. 1 This is a schematic diagram of the structure of a blue-green dual-band light-emitting diode epitaxial wafer according to an embodiment of the present invention; Fig. 2 This is a schematic diagram of the structure of a multi-quantum-well light-emitting layer according to an embodiment of the present invention; Fig. 3 This is a schematic diagram of the structure of the first green light barrier layer according to an embodiment of the present invention; Fig. 4 This is a schematic diagram of the structure of the second green light barrier layer according to an embodiment of the present invention. Detailed Implementation

[0018] 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.

[0019] See Figs. 1 to 4 As shown, this embodiment of the invention provides a blue-green dual-band light-emitting diode epitaxial wafer, comprising a substrate 100, a buffer layer 200, an N-type semiconductor layer 300, a low-temperature stress relief layer 400, a multi-quantum well light-emitting layer 500, an electron blocking layer 600, and a P-type semiconductor layer 700, which are sequentially stacked along the epitaxial direction.

[0020] The multi-quantum light-emitting layer 500 includes a first blue InGaN layer 510, a first blue barrier layer 520, a first green barrier layer 530, a first green InGaN layer 540, a second green barrier layer 550, a second blue InGaN layer 560, and a second blue barrier layer 570, which are sequentially and periodically grown along the epitaxial direction, with a period number of 2 to 7. Examples of period numbers are 2, 3, 4, 5, 6, and 7.

[0021] The multi-quantum-well light-emitting layer in this embodiment of the invention can excite a blue light band and a green light band, thereby reducing the cost of RGB-LED backlight sources and reducing the use of phosphors in white LED backlight sources.

[0022] The first blue InGaN layer 510 emits light at a wavelength of 391nm~487nm; The first green InGaN layer 540 emits light at a wavelength of 511 nm to 565 nm. The emission wavelength of the second blue InGaN layer 560 is 391nm~487nm.

[0023] Preferably, the first blue InGaN layer 510 is a single-layer or multi-layer structure made of InGaN material without intentional doping, the In content is X1, 0.05≤X1≤0.19, the growth thickness is H1, H1 is 2.1nm~4.9nm, the growth temperature is 720℃~880℃, and the growth pressure is 30torr~360torr. Exemplary values ​​of X1 are 0.05, 0.07, 0.08, 0.09, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, and 0.19, but are not limited thereto. Examples of H1 wavelengths include 2.1nm, 2.3nm, 2.5nm, 2.7nm, 2.9nm, 3.3nm, 3.7nm, 3.9nm, 4.1nm, 4.2nm, 4.5nm, 4.7nm, and 4.9nm, but are not limited thereto. Examples of growth temperatures include 720℃, 730℃, 770℃, 790℃, 810℃, 830℃, 860℃, and 880℃, but are not limited thereto. Examples of growth pressures include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited thereto.

[0024] Preferably, the first blue light barrier layer 520 is a single-layer or multi-layer structure, comprising a first GaN layer and / or a first AlGaN layer, with a growth thickness of 6.2 nm to 15.9 nm, a growth temperature of 720 °C to 980 °C, and a growth pressure of 30 torr to 360 torr. Exemplary growth thicknesses include 6.2 nm, 6.9 nm, 7.6 nm, 7.9 nm, 8.6 nm, 9.6 nm, 11.9 nm, 12.8 nm, 15.6 nm, and 15.9 nm, but are not limited thereto. Exemplary growth temperatures include 720 °C, 730 °C, 770 °C, 790 °C, 810 °C, 830 °C, 860 °C, and 880 °C, but are not limited thereto. Examples of growth stresses include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0025] The first GaN layer is doped with Si, and the Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³~9.6×10 17 / cm³. An exemplary Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³, 2.7×10 17 / cm³, 3.8×1017 / cm³, 4.3×10 17 / cm³, 5.9×10 17 / cm³, 6.7×10 17 / cm³, 8.1×10 17 / cm³, 8.5×10 17 / cm³, 9.3×10 17 / cm³, 9.6×10 17 / cm³, but not limited to this.

[0026] The Al component content of the first AlGaN layer is Y1, where Y1 ≤ 0.65. Examples of Y1 are 0.11, 0.19, 0.23, 0.25, 0.39, 0.42, 0.53, 0.61, and 0.65, but it is not limited to these.

[0027] Preferably, the first green light barrier layer 530 includes a low-level barrier layer 531, a high-level barrier layer 532, and a polarization compensation barrier layer 533 that grow sequentially along the epitaxial direction.

[0028] The first green InGaN layer 540 is a single-layer or multi-layer structure made of undoped InGaN material. The In content is X2, where 0.22 ≤ X2 ≤ 0.28. The growth thickness is H2, where H2 is 2.0 nm to 4.8 nm. The growth temperature is 680 °C to 880 °C, and the growth pressure is 30 torr to 360 torr. Examples of X2 include 0.22, 0.23, 0.25, 0.26, 0.27, and 0.28, but are not limited to these. Examples of H2 include 2.1 nm, 2.3 nm, 2.6 nm, 2.9 nm, 3.4 nm, 3.5 nm, 3.9 nm, 4.1 nm, 4.3 nm, 4.5 nm, and 4.8 nm, but are not limited to these. Examples of growth temperatures include 720℃, 730℃, 770℃, 790℃, 810℃, 830℃, 860℃, and 880℃, but are not limited to these. Examples of growth pressures include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0029] The second green light barrier layer 550 includes a back-well polarization compensation barrier layer 551, a back-well high-level barrier layer 552, and a back-well low-level barrier layer 553 that are grown sequentially along the epitaxial direction.

[0030] Both the low-level barrier layer 531 before the well and the low-level barrier layer 553 after the well are made of Si-doped GaN material, with a Si doping concentration of 1.2 × 10⁻⁶. 17 / cm³~8.7×10 17 The growth thickness was 1 nm to 9 nm, the growth temperature was 720°C to 980°C, and the growth pressure was 30 torr to 360 torr. An example Si doping concentration was 1.5 × 10⁻⁶ cm³. 17 / cm³, 2.7×10 17 / cm³, 3.8×10 17 / cm³, 4.3×10 17 / cm³, 5.9×10 17 / cm³, 6.7×10 17 / cm³, 8.1×10 17 / cm³, 8.5×10 17 / cm³, but not limited to this. Exemplary growth thicknesses include 1nm, 1.5nm, 2.3nm, 3.3nm, 5.5nm, 6.9nm, 7.6nm, 7.9nm, 8.6nm, and 9nm, but not limited to this. Exemplary growth temperatures include 720℃, 730℃, 770℃, 790℃, 810℃, 830℃, 860℃, 880℃, and 980℃, but not limited to this. Exemplary growth pressures include 30torr, 50torr, 70torr, 100torr, 150torr, 200torr, 210torr, 260torr, 290torr, 310torr, 350torr, and 360torr, but not limited to this.

[0031] Both the pre-well high-energy barrier layer 532 and the post-well high-energy barrier layer 552 are made of undoped AlGaN material, with an Al content of less than or equal to 0.5%, a growth thickness of 0.2 nm to 3 nm, a growth temperature of 720 °C to 980 °C, and a growth pressure of 30 torr to 360 torr. Examples of Al content include 0.1, 0.15, 0.23, 0.28, 0.35, 0.39, 0.42, and 0.5%, but are not limited to these. Examples of growth thickness include 0.2 nm, 0.8 nm, 1.5 nm, 1.7 nm, 2.3 nm, 2.8 nm, and 3 nm, but are not limited to these. Examples of growth temperature include 720 °C, 730 °C, 770 °C, 790 °C, 810 °C, 830 °C, 860 °C, 880 °C, and 980 °C, but are not limited to these. Examples of growth stresses include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0032] Both the pre-well polarization compensation barrier layer 533 and the post-well polarization compensation barrier layer 551 are made of undoped AlGaInN material, with an Al content of less than or equal to 0.5% and an In content of less than or equal to 0.28%. The growth thickness is 0.2 nm to 3 nm, the growth temperature is 720 °C to 980 °C, and the growth pressure is 30 torr to 360 torr. Examples of Al content include 0.1%, 0.15%, 0.23%, 0.28%, 0.35%, 0.39%, 0.42%, and 0.5%, but are not limited to these. Examples of In content include 0.11%, 0.17%, 0.19%, 0.21%, 0.23%, 0.25%, and 0.28%, but are not limited to these. Examples of growth thickness include 0.2 nm, 0.5 nm, 1.2 nm, 1.5 nm, 1.9 nm, 2.2 nm, 2.8 nm, and 3 nm, but are not limited to these. Examples of growth temperatures include 720℃, 730℃, 770℃, 790℃, 810℃, 830℃, 860℃, 880℃, and 980℃, but are not limited to these. Examples of growth pressures include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0033] Specifically, H2 atmosphere heat treatment is required before depositing the pre-well high-energy barrier layer 532 and before depositing the post-well high-energy barrier layer 552.

[0034] Specifically, heat treatment is performed in an H2 atmosphere for a duration of 5 to 180 seconds, at a temperature of 800°C to 1030°C, and at a pressure of 30 torr to 360 torr. Examples of treatment times include 5 seconds, 50 seconds, 70 seconds, 90 seconds, 100 seconds, 120 seconds, 150 seconds, and 180 seconds, but these are not limited to these. Examples of treatment temperatures include 800°C, 820°C, 870°C, 910°C, 930°C, 980°C, and 1030°C, but these are not limited to these. Examples of treatment pressures include 0 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but these are not limited to these.

[0035] The low-level barrier layer 531 before the well and the low-level barrier layer 553 after the well are made of Si-doped GaN material with low doping concentration, which can obtain a barrier layer with high crystal quality and flatness.

[0036] The pre-well high-level barrier layer 532 and post-well high-level barrier layer 552 are made of undoped AlGaN material and are heat-treated in an H2 atmosphere before deposition. The surface roughness of the epitaxial layer material increases after treatment, while the small Al atoms can form a dense AlGaN film, which fills the rough surface, reduces the roughness of the first green InGaN layer, makes its interface smoother and reduces the defect density. At the same time, the higher bandgap of Al atoms can bind charge carriers within the first green InGaN layer to achieve radiative recombination luminescence, improve luminescence efficiency and effectively prevent electron leakage caused by electron overflow.

[0037] The pre-well polarization compensation barrier layer 533 and post-well polarization compensation barrier layer 551 are made of AlGaInN material without intentional doping. Since the energy band of the first green InGaN layer is affected by the spontaneous polarization electric field and the piezoelectric polarization electric field, and the spontaneous polarization electric field is opposite in direction to the applied electric field, the influence of the spontaneous polarization electric field of the first green InGaN layer can be offset by increasing the applied electric field. However, the piezoelectric polarization electric field is in the same direction as the applied electric field and cannot be offset by the applied electric field. Therefore, by selecting AlGaInN material and controlling its Al composition, In composition, and growth thickness, the piezoelectric polarization electric field intensity of the first green InGaN layer can be controlled. This reduces the difference in polarization electric field intensity among the first blue InGaN layer, the first blue barrier layer, the first green barrier layer, the first green InGaN layer, the second green barrier layer, the second blue InGaN layer, and the second blue barrier layer. Consequently, the wavelength shift amplitude is more consistent under different current densities, effectively improving the stability of the intensity ratio of light in each band and increasing the luminous efficiency.

[0038] Before the high-energy barrier layer 532 in front of the deposit trap and before the high-energy barrier layer 552 behind the trap, H2 atmosphere heat treatment is required. This will decompose the defects such as poor crystal quality material and high-In content In clusters on the surface of the epitaxial wafer, which is beneficial to improve the crystal quality of the material. At the same time, the rough surface of the barrier material can reduce the in-plane total internal reflection and light absorption loss of photons in the semiconductor material, and improve the light extraction efficiency.

[0039] More preferably, after depositing the pre-well low-energy barrier layer 531 and before depositing the pre-well high-energy barrier layer 532, the heat treatment in H2 atmosphere is performed for a treatment time of t1 and a treatment temperature of W1; after depositing the post-well polarization compensation barrier layer 551 and before depositing the post-well high-energy barrier layer 552, the heat treatment in H2 atmosphere is performed for a treatment time of t2 and a treatment temperature of W2; wherein, t1>t2, W1>W2.

[0040] First, the longer heat treatment time and higher heat treatment temperature of the 531 low-barrier layer in front of the well allow for more thorough decomposition of high-In cluster defects on the surface in the region in front of the well, resulting in a smoother interface. This reduces non-radiative recombination centers, ensuring efficient injection of electron-hole pairs into the first green InGaN layer and improving the internal quantum efficiency in the green light band.

[0041] Secondly, the pre-well region is treated at a higher temperature and for a longer time to avoid In composition segregation caused by excessive annealing of the post-well polarization compensation barrier layer 551, maintain the polarization electric field compensation effect, and prevent carrier leakage.

[0042] In traditional dual-band LEDs, the green light efficiency is often lower than that of the blue light. Strong pre-well thermal processing improves the crystal quality of the first green InGaN layer 540, bringing the green light efficiency close to that of a single green LED chip. Meanwhile, gentle post-well processing ensures the stability of the second blue InGaN layer 560, achieving balanced blue-green dual-peak luminescence.

[0043] Preferably, the second blue InGaN layer 560 is a single-layer or multi-layer structure made of undoped InGaN material, with an In content of X3, 0.05 ≤ X3 ≤ 0.19, a growth thickness of H3, H3 being 2.1 nm to 4.9 nm, a growth temperature of 720 °C to 880 °C, and a growth pressure of 30 torr to 360 torr. Exemplary values ​​of X3 include 0.05, 0.07, 0.09, 0.12, 0.15, 0.17, and 0.19, but are not limited thereto. Exemplary values ​​of H3 include 2.1 nm, 2.5 nm, 2.7 nm, 3.3 nm, 3.5 nm, 3.8 nm, 4.1 nm, 4.3 nm, 4.5 nm, and 4.9 nm, but are not limited thereto. Examples of growth temperatures include 720℃, 730℃, 770℃, 790℃, 810℃, 830℃, 860℃, and 880℃, but are not limited to these. Examples of growth pressures include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0044] Preferably, the second blue light barrier layer 570 is a single-layer or multi-layer structure, comprising a second GaN layer and / or a second AlGaN layer, with a growth thickness of 5.8 nm to 15.3 nm, a growth temperature of 720 °C to 980 °C, and a growth pressure of 30 torr to 360 torr. Exemplary growth thicknesses include 5.8 nm, 6.3 nm, 7.7 nm, 8.1 nm, 8.6 nm, 9.8 nm, 10.3 nm, 10.5 nm, 11.5 nm, 13.6 nm, 14.8 nm, and 15.3 nm, but are not limited thereto. Exemplary growth temperatures include 720 °C, 730 °C, 770 °C, 790 °C, 810 °C, 830 °C, 860 °C, 880 °C, and 980 °C, but are not limited thereto. Examples of growth stresses include 30 torr, 50 torr, 70 torr, 100 torr, 150 torr, 200 torr, 210 torr, 260 torr, 290 torr, 310 torr, 350 torr, and 360 torr, but are not limited to these.

[0045] The second GaN layer is doped with Si, and the Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³~9.6×10 17 / cm³. An exemplary Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³, 2.7×10 17 / cm³, 3.8×10 17 / cm³, 4.3×10 17 / cm³, 5.9×10 17 / cm³, 6.7×10 17 / cm³, 8.1×10 17 / cm³, 8.5×10 17 / cm³, 9.3×10 17 / cm³, 9.6×10 17 / cm³, but not limited to this.

[0046] The Al component content of the second AlGaN layer is Y2, where Y2 ≤ 0.35. Examples of Y2 values ​​are 0.11, 0.15, 0.27, 0.31, 0.32, and 0.35, but it is not limited to these.

[0047] More preferably, the In content relationship of the first blue InGaN layer 510, the first green InGaN layer 540, and the second blue InGaN layer 560 is X2>X1=X3. The In content of each InGaN layer in the multi-quantum-well emitting layer forms a gradient design that first increases and then decreases. The above structural and process design can effectively reduce the lattice mismatch stress between the InGaN layer and the barrier layer material. The reduction of defects caused by the lattice mismatch stress can significantly improve the quality of the multi-quantum-well emitting layer, which is beneficial to improving the radiative recombination efficiency of the active region, thereby improving the luminous efficiency and production yield of the epitaxial wafer. At the same time, the reduction of the lattice mismatch stress between the quantum well InGaN material and the barrier layer material can reduce the band bending phenomenon caused by the piezoelectric polarization effect of the quantum well InGaN material, thereby improving the coupling degree between the electron and hole wave functions in the quantum well InGaN material, so as to improve the radiative recombination efficiency in the multi-quantum-well emitting layer and ultimately improve the luminous efficiency of the epitaxial wafer.

[0048] Existing multi-quantum-well (MFU) light-emitting layers employ an InGaN-GaN structure. The lattice mismatch between these two structures often leads to the formation of polarization electric fields, with varying intensities for MFU layers of different In compositions. When driven by different currents, these polarization electric fields result in varying band tilts, causing changes in the intensity ratio of blue and green light wavelengths and resulting in unstable emission wavelengths. Similarly, different polarization electric fields also cause varying degrees of carrier leakage, leading to different levels of efficiency degradation across different emission bands, which also contributes to wavelength instability.

[0049] Optimally, the growth thicknesses of the first blue InGaN layer 510, the second green InGaN layer 540, and the third blue InGaN layer 560 are related as H2.

[0050] Accordingly, the present invention also provides a method for fabricating a blue-green dual-band light-emitting diode epitaxial wafer, comprising the following steps: Provide a substrate 100; A buffer layer 200 is deposited on the substrate 100; An N-type semiconductor layer 300 is deposited on the buffer layer 200; A low-temperature stress relief layer 400 is deposited on the N-type semiconductor layer 300; A multi-quantum-well light-emitting layer 500 is deposited on the low-temperature stress-relieving layer 400; ​An electron blocking layer 600 is deposited on the multi-quantum well emitting layer 500; A P-type semiconductor layer 700 is deposited on the electron blocking layer 600; The multi-quantum light-emitting layer 500 includes a first blue light InGaN layer 510, a first blue light barrier layer 520, a first green light barrier layer 530, a first green light InGaN layer 540, a second green light barrier layer 550, a second blue light InGaN layer 560, and a second blue light barrier layer 570 that are periodically and alternately grown along the epitaxial direction. The first green light barrier layer 530 includes a low-level barrier layer 531, a high-level barrier layer 532, and a polarization compensation barrier layer 533 that grow sequentially along the epitaxial direction. The second green light barrier layer 550 includes a back-well polarization compensation barrier layer 551, a back-well high-level barrier layer 552, and a back-well low-level barrier layer 553 that are grown sequentially along the epitaxial direction. Specifically, H2 atmosphere heat treatment is required before depositing the pre-well high-energy barrier layer 532 and before depositing the post-well high-energy barrier layer 552.

[0051] Preferably, the growth cycle number of the multi-quantum-well light-emitting layer 500 is 2 to 7; The first blue InGaN layer 510 emits light at a wavelength of 391nm~487nm; The emission wavelength of the second green InGaN layer 540 is 511nm~565nm; The emission wavelength of the third blue InGaN layer 560 is 391nm~487nm.

[0052] The following specific embodiments will provide further explanation.

[0053] Example 1 This embodiment provides a blue-green dual-band light-emitting diode epitaxial wafer, comprising a substrate, a buffer layer, an N-type semiconductor layer, a low-temperature stress relief layer, a multi-quantum-well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer sequentially stacked along the epitaxial direction; The multi-quantum light-emitting layer includes a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer, and a second blue light barrier layer that are grown alternately and periodically along the epitaxial direction, with a period number of 5. The first blue light InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping, with an In content of X1, X1=0.12, a growth thickness of H1, H1=3.5nm, a growth temperature of 800℃, and a growth pressure of 250 torr. The first blue light barrier layer is a multilayer structure, including a first GaN layer and a first AlGaN layer, with a growth thickness of 12.5 nm, a growth temperature of 850 °C, and a growth pressure of 250 torr; The first GaN layer is doped with Si, and the Si doping concentration is 5.5 × 10⁻⁶. 17 / cm³; The Al component content of the AlGaN layer is Y1, where Y1 = 0.35; The first green light barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction. The low-level barrier layer in front of the well is made of Si-doped GaN material with a Si doping concentration of 4.5 × 10⁻⁶. 17 / cm³, growth thickness of 5nm, growth temperature of 850℃, growth pressure of 250torr; The high-level barrier layer in front of the well is made of undoped AlGaN material, with an Al content of Y. 01 Y 01 =0.25, growth thickness of 1.5 nm, growth temperature of 850℃, and growth pressure of 250 torr; The pre-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 02 Y 02 =0.25, the content of In component is X 01 X 01 =0.14, growth thickness of 1.5 nm, growth temperature of 850℃, growth pressure of 250 torr; The first green InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping, with an In content of X2, X2=0.19, a growth thickness of H2, H2=2.4nm, a growth temperature of 780℃, and a growth pressure of 250 torr. The second green light barrier layer includes a back-well polarization compensation barrier layer, a back-well high-level barrier layer, and a back-well low-level barrier layer that grow sequentially along the epitaxial direction. The post-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 03 Y 03 =0.25, the content of In component is X 02 X 02 =0.14, growth thickness of 1.5 nm, growth temperature of 850℃, growth pressure of 250 torr; The high-barrier layer behind the well is made of undoped AlGaN material, with an Al content of Y. 04 Y04 =0.25, growth thickness of 1.5 nm, growth temperature of 850℃, and growth pressure of 250 torr; The low-level barrier layer behind the well is made of Si-doped GaN material, with a Si doping concentration of 4.5 × 10⁻⁶. 17 / cm³, growth thickness of 5nm, growth temperature of 850℃, growth pressure of 250torr; The second blue light InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping, with an In content of X3, X3=0.12, a growth thickness of H3, H3=3.5nm, a growth temperature of 800℃, and a growth pressure of 250 torr. The second blue light barrier layer is a multilayer structure, which includes a second GaN layer and a second AlGaN layer, with a growth thickness of 10 nm, a growth temperature of 780 °C, and a growth pressure of 250 torr. The second GaN layer is doped with Si, and the Si doping concentration is 4.3 × 10⁻⁶. 17 / cm³; The Al component content of the second AlGaN layer is Y2, Y2=0.18.

[0054] In particular, H2 atmosphere heat treatment is required before depositing the pre-well high-energy level barrier layer and before depositing the post-well high-energy level barrier layer. Before depositing the high-level barrier layer in front of the well, heat treatment is performed in H2 atmosphere for a time of t1, t1 = 100s, a temperature of W1, W1 = 950℃, and a pressure of 250 torr. Before depositing the high-level barrier layer after the well, a heat treatment in H2 atmosphere is performed for a time of t2, t2 = 75 s, a temperature of W2, W2 = 880 °C, and a pressure of 250 torr.

[0055] Example 2 The difference between this embodiment and Embodiment 1 is that: Before depositing the high-level barrier layer in front of the well, heat treatment is performed in H2 atmosphere for a time of t1, t1 = 180s, a temperature of W1, W1 = 1000℃, and a pressure of 250 torr. Before depositing the high-level barrier layer behind the trap, a heat treatment in H2 atmosphere is performed for a time of t2, t2 = 180 s, a temperature of W2, W2 = 1000 °C, and a pressure of 250 torr.

[0056] Example 3 The difference between this embodiment and Embodiment 1 is that: Before depositing the high-level barrier layer in front of the well, heat treatment is performed in H2 atmosphere for a time of t1, t1 = 30s, a temperature of W1, W1 = 810℃, and a pressure of 250 torr. Before depositing the high-level barrier layer behind the trap, a heat treatment in H2 atmosphere is performed for a time of t2, t2 = 120 s, a temperature of W2, W2 = 900 °C, and a pressure of 250 torr.

[0057] Example 4 The difference between this embodiment and Embodiment 1 is that: The low-level barrier layer in front of the well is made of Si-doped GaN material with a Si doping concentration of 2.3 × 10⁻⁶. 17 / cm³, growth thickness of 1.5nm, growth temperature of 730℃, growth pressure of 250torr; The high-level barrier layer in front of the well is made of undoped AlGaN material, with an Al content of Y. 01 Y 01 =0.15, growth thickness of 1.1 nm, growth temperature of 730℃, and growth pressure of 250 torr; The pre-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 02 Y 02 =0.13, the content of In component is X 01 X 01 =0.11, with a growth thickness of 1.1 nm, a growth temperature of 750 °C, and a growth pressure of 250 torr; The post-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 03 Y 03 =0.45, the content of In component is X 02 X 02 =0.25, the growth thickness was 2.5 nm, the growth temperature was 940℃, and the growth pressure was 250 torr; The high-barrier layer behind the well is made of undoped AlGaN material, with an Al content of Y. 04 Y 04 =0.41, growth thickness of 2.5 nm, growth temperature of 920℃, and growth pressure of 250 torr; The low-level barrier layer behind the well is made of Si-doped GaN material, with a Si doping concentration of 8.1 × 10⁻⁶. 17 / cm³, growth thickness of 8.4nm, growth temperature of 900℃, and growth pressure of 250torr.

[0058] Example 5 The difference between this embodiment and Embodiment 1 is that: The low-level barrier layer in front of the well is made of Si-doped GaN material with a Si doping concentration of 8.5 × 10⁻⁶. 17 / cm³, growth thickness of 9nm, growth temperature of 970℃, growth pressure of 250torr; The high-level barrier layer in front of the well is made of undoped AlGaN material, with an Al content of Y. 01 Y 01 =0.49, growth thickness of 2.7 nm, growth temperature of 900℃, and growth pressure of 250 torr; The pre-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 02 Y 02 =0.43, the content of In component is X 01 X 01 =0.27 The growth thickness was 4.8 nm, the growth temperature was 960℃, and the growth pressure was 250 torr; The post-well polarization compensation barrier layer is made of undoped AlGaInN material, with an Al content of Y. 03 Y 03 =0.1, the content of In component is X 02 X 02 =0.1 The growth thickness was 0.5 nm, the growth temperature was 730℃, and the growth pressure was 250 torr; The high-barrier layer behind the well is made of undoped AlGaN material, with an Al content of Y. 04 Y 04 =0.12, growth thickness of 0.3 nm, growth temperature of 720℃, and growth pressure of 250 torr; The low-level barrier layer behind the well is made of Si-doped GaN material, with a Si doping concentration of 1.5 × 10⁻⁶. 17 / cm³, growth thickness of 1nm, growth temperature of 720℃, and growth pressure of 250 torr.

[0059] Example 6 The difference between this embodiment and Embodiment 1 is that: The growth thickness of the first blue InGaN layer is H1, where H1 = 2.9 nm; The growth thickness of the first green InGaN layer is H2, where H2 = 4.8 nm; The growth thickness of the second blue InGaN layer is H3, where H3 = 2.1 nm.

[0060] Example 7 The difference between this embodiment and Embodiment 1 is that: The In content of the first blue InGaN layer is X1, where X1 = 0.19. The In content of the first green InGaN layer is X2, X2=0.28; The In content of the second blue InGaN layer is X3, X3=0.13.

[0061] Comparative Example 1 An LED epitaxial wafer is provided, comprising a substrate, a buffer layer, an N-type semiconductor layer, a low-temperature stress relief layer, a multi-quantum-well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer sequentially stacked along the epitaxial direction; The multi-quantum-well light-emitting layer has a periodic structure of alternating InGaN multi-quantum-well layers and GaN quantum barrier layers, with a stacking period of 8. Within a single period, the InGaN quantum well layer has an In composition of 0.17, and the thickness of the InGaN quantum well layer is 3.4 nm; the thickness of the GaN quantum barrier layer is 13 nm.

[0062] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: The multi-quantum-well light-emitting layer comprises a first blue InGaN layer, a first blue barrier layer, a first green InGaN layer, a first green barrier layer, a second blue InGaN layer, and a second blue barrier layer that are periodically and alternately grown along the epitaxial direction, with a period number of 5. The first green light barrier layer is a single-layer or multi-layer structure, which includes a GaN layer and an AlGaN layer, with a growth thickness of 10 nm, a growth temperature of 780 °C, and a growth pressure of 250 torr. The GaN layer is doped with Si, and the Si doping concentration is 4.3 × 10⁻⁶. 17 / cm³; The Al content of the AlGaN layer is 0.18%.

[0063] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: No H2 atmosphere heat treatment is performed before the deposition of the pre-well high-level barrier layer and before the deposition of the post-well high-level barrier layer.

[0064] The epitaxial wafers obtained in the examples and comparative examples were fabricated into 20μm×20μm LED chips, and subjected to 20A / cm 2The chip's luminous efficacy improvement, WD STD (nm) and epitaxial wafer XRD test results were obtained under the working current density. The luminous efficacy improvement was calculated based on Comparative Example 1.

[0065] It should be noted that arcsec(002) data can characterize screw dislocations, while arcsec(102) data can characterize mixed dislocations of screw and edge dislocations. The smaller the value of arcsec(002) or arcsec(102), the lower the dislocation density and the better the crystal quality. WD STD mainly reflects the wavelength standard deviation. The smaller the standard deviation, the more concentrated the chip parameter distribution and the more stable the manufacturing process.

[0066] It should be noted that the color rendering index (CRI) is a metric established by the International Commission on Illumination (ICI) to evaluate the color rendering performance of light sources. It measures the ability of a light source to reproduce the colors of objects. Its core principle is to quantify color rendering performance by comparing the color difference between the tested light source and a standard color sample under a reference light source.

[0067] Evaluation criteria: Ra≥80: Good color rendering, meeting general lighting needs; Ra≥95: Excellent color rendering, close to the effect of natural light; Ra<70: Poor color rendering, which may lead to color distortion.

[0068] The fidelity index is a light source color quality evaluation index proposed by the Illuminating Engineering Society of North America in the TM-30-15 standard. It is specifically used to evaluate how well a light source reproduces the true colors of an object.

[0069] Evaluation criteria: Rf≥80: Good fidelity; Rf≥95: Excellent fidelity; Rf<70: Insufficient fidelity, obvious color distortion.

[0070] The test results are as follows:

[0071] As can be seen from the above test results, the present invention provides a blue-green dual-band light-emitting diode epitaxial wafer. The multi-quantum-well light-emitting layer in the epitaxial wafer includes a first blue InGaN layer, a first blue barrier layer, a first green barrier layer, a first green InGaN layer, a second green barrier layer, a second blue InGaN layer, and a second blue barrier layer, grown sequentially and alternately along the epitaxial direction. That is, the light-emitting diode prepared from this epitaxial wafer can excite a light source in both a blue and a green light band, thereby reducing the cost of RGB-LED backlight sources and reducing the amount of phosphor used in white LED backlight sources.

[0072] Secondly, a first green barrier layer and a second green barrier layer are set on both sides of the first green InGaN layer. The first green barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction. The second green barrier layer includes a polarization compensation barrier layer in back of the well, a high-level barrier layer in back of the well, and a low-level barrier layer in back of the well, which are grown sequentially along the epitaxial direction. Before depositing the high-level barrier layer in front of the well and the high-level barrier layer in back of the well, H2 atmosphere heat treatment is performed. This decomposes the defects such as poor crystal quality materials and high-In-content In clusters on the surface of the epitaxial wafer, which is beneficial to improving the crystal quality of the material. At the same time, the rough surface of the barrier layer material is formed, which can reduce the in-plane total internal reflection and light absorption loss of photons in the semiconductor material and improve the light extraction efficiency.

[0073] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A blue-green dual-band light-emitting diode epitaxial wafer, comprising a substrate, a buffer layer, an N-type semiconductor layer, a low-temperature stress relief layer, a multi-quantum-well light-emitting layer, an electron blocking layer, and a P-type semiconductor layer sequentially stacked along the epitaxial direction, characterized in that: The multi-quantum light-emitting layer includes a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer, and a second blue light barrier layer that are periodically and alternately grown along the epitaxial direction. The first green light barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction. The second green light barrier layer includes a back-well polarization compensation barrier layer, a back-well high-level barrier layer, and a back-well low-level barrier layer that grow sequentially along the epitaxial direction. Specifically, H2 atmosphere heat treatment is required before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy barrier layer.

2. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The growth cycle number of the multi-quantum-well light-emitting layer is 2 to 7; The emission wavelength of the first blue InGaN layer is 391nm~487nm; The emission wavelength of the first green InGaN layer is 511nm~565nm; The emission wavelength of the second blue InGaN layer is 391nm~487nm.

3. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 1, characterized in that, Both the pre-well low-level barrier layer and the post-well low-level barrier layer are made of Si-doped GaN material, with a Si doping concentration of 1.2 × 10⁻⁶. 17 / cm³~8.7×10 17 / cm³, the growth thickness was 1nm~9nm, the growth temperature was 720℃~980℃, and the growth pressure was 30torr~360torr; Both the pre-well high-level barrier layer and the post-well high-level barrier layer are made of AlGaN material without intentional doping, with an Al content of less than or equal to 0.5, a growth thickness of 0.2 nm to 3 nm, a growth temperature of 720 °C to 980 °C, and a growth pressure of 30 torr to 360 torr. Both the pre-well polarization compensation barrier layer and the post-well polarization compensation barrier layer are made of AlGaInN material without intentional doping. The content of Al component is less than or equal to 0.5%, the content of In component is less than or equal to 0.28%, the growth thickness is 0.2nm~3nm, the growth temperature is 720℃~980℃, and the growth pressure is 30torr~360torr.

4. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 1, 2, or 3, characterized in that, Before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy layer, the process includes heat treatment in an H2 atmosphere for 5 s to 180 s, at a temperature of 800 ℃ to 1030 ℃, and at a pressure of 30 torr to 360 torr.

5. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 4, characterized in that, Before depositing the high-level barrier layer in front of the well, a heat treatment in H2 atmosphere is performed for a treatment time of t1 and a treatment temperature of W1. Before depositing the high-level barrier layer behind the well, heat treatment in H2 atmosphere is performed for a treatment time of t2 and a treatment temperature of W2. Where t1>t2, W1>W2.

6. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The first blue light InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping. The In content is X1, 0.05≤X1≤0.19, the growth thickness is H1, H1 is 2.1nm~4.9nm, the growth temperature is 720℃~880℃, and the growth pressure is 30torr~360torr. The first green InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping, with an In content of X2, 0.22≤X2≤0.28, a growth thickness of H2, H2 is 2.0nm~4.8nm, a growth temperature of 680℃~880℃, and a growth pressure of 30torr~360torr. The second blue InGaN layer is a single-layer or multi-layer structure made of InGaN material without intentional doping. The In content is X3, 0.05≤X3≤0.19, the growth thickness is H3, H3 is 2.1nm~4.9nm, the growth temperature is 720℃~880℃, and the growth pressure is 30torr~360torr.

7. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 6, characterized in that, The content relationship of In components in the first blue InGaN layer, the first green InGaN layer, and the second blue InGaN layer satisfies X2>X1=X3; The growth thicknesses of the first blue InGaN layer, the first green InGaN layer, and the second blue InGaN layer satisfy H2. <H1=H3。 8. The blue-green dual-band light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The first blue light barrier layer is a single-layer or multi-layer structure, which includes a first GaN layer and / or a first AlGaN layer, with a growth thickness of 6.2nm~15.9nm, a growth temperature of 720℃~980℃, and a growth pressure of 30torr~360torr. The first GaN layer is doped with Si, and the Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³~9.6×10 17 / cm³; The Al component content of the first AlGaN layer is Y1, where Y1≤0.65; The second blue light barrier layer is a single-layer or multi-layer structure, which includes a second GaN layer and / or a second AlGaN layer, with a growth thickness of 5.8 nm to 15.3 nm, a growth temperature of 720 °C to 980 °C, and a growth pressure of 30 torr to 360 torr. The second GaN layer is doped with Si, and the Si doping concentration is 1.5 × 10⁻⁶. 17 / cm³~9.6×10 17 / cm³; The Al component content of the second AlGaN layer is Y2, where Y2≤0.

35.

9. A method for fabricating a blue-green dual-band light-emitting diode epitaxial wafer as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Provide a substrate; A buffer layer is deposited on the substrate; An N-type semiconductor layer is deposited on the buffer layer; A low-temperature stress relief layer is deposited on the N-type semiconductor layer; A multi-quantum-well light-emitting layer is deposited on the low-temperature stress-relieving layer; An electron blocking layer is deposited on the multi-quantum-well light-emitting layer; A P-type semiconductor layer is deposited on the electron blocking layer; The multi-quantum light-emitting layer includes a first blue light InGaN layer, a first blue light barrier layer, a first green light barrier layer, a first green light InGaN layer, a second green light barrier layer, a second blue light InGaN layer, and a second blue light barrier layer that are periodically and alternately grown along the epitaxial direction. The first green light barrier layer includes a low-level barrier layer in front of the well, a high-level barrier layer in front of the well, and a polarization compensation barrier layer in front of the well, which are grown sequentially along the epitaxial direction. The second green light barrier layer includes a back-well polarization compensation barrier layer, a back-well high-level barrier layer, and a back-well low-level barrier layer that grow sequentially along the epitaxial direction. Specifically, H2 atmosphere heat treatment is required before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy barrier layer.

10. The method for fabricating a blue-green dual-band light-emitting diode epitaxial wafer as described in claim 9, characterized in that, The growth cycle number of the multi-quantum-well light-emitting layer is 2 to 7; The emission wavelength of the first blue InGaN layer is 391nm~487nm; The emission wavelength of the second green InGaN layer is 511nm~565nm; The emission wavelength of the third blue InGaN layer is 391nm~487nm; Before depositing the pre-well high-energy barrier layer and before depositing the post-well high-energy layer, the process includes heat treatment in an H2 atmosphere for 5 s to 180 s, at a temperature of 800 ℃ to 1030 ℃, and at a pressure of 30 torr to 360 torr.

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