Epitaxial structure, preparation method thereof and light emitting diode

Abstract

The invention discloses an epitaxial structure, a preparation method thereof and a light-emitting diode, and belongs to the technical field of semiconductors. The epitaxial structure comprises a substrate, a light-emitting layer formed on the substrate, an N-type current expansion layer and a P-type current expansion layer which are formed on the two sides of the light-emitting layer, and an electron blocking layer formed between the light-emitting layer and the P-type current expansion layer. Wherein the light-emitting layer comprises at least one pair of quantum well layer In < x > Ga < 1-x > N and quantum barrier layer In < y > Ga < 1-y > N, and y < lt > is greater than or equal to 0; x < 1. The material components of the quantum well layer InxGa1-xN and the quantum barrier layer InyGa1-yN both comprise indium, gallium and nitrogen, so that lattice mismatch is reduced, compression stress caused by lattice mismatch is reduced, the piezoelectric polarization effect is weakened, meanwhile, the recombination efficiency of current carriers is improved, the external quantum efficiency is improved, and the performance of the light emitting diode is improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to an epitaxial structure and a preparation method thereof, and a light emitting diode. Background Art

[0002] At present, most light-emitting diodes use aluminum gallium indium phosphide (AlGaInP) as the light-emitting material. However, due to the long carrier diffusion length and the strong surface non-radiative recombination ability of AlGaInP materials, in micron-scale LED units, the efficiency of AlGaInP-based LEDs decreases faster due to the significant increase in the proportion of sidewall area, which limits its application in ultra-high-definition display fields such as augmented reality (AR) and virtual reality (VR).

[0003] Indium gallium nitride (InGaN)-based light-emitting diodes are one of the main research directions at present. However, in the related technologies, InGaN-based light-emitting diodes mainly have problems such as poor epitaxial crystal quality and unreasonable quantum well structure design, which will lead to a decrease in the external quantum efficiency of the light-emitting diodes and affect the performance of the light-emitting diodes. Summary of the invention

[0004] The present application provides an epitaxial structure of an InGaN-based light-emitting diode, a preparation method thereof, and a light-emitting diode, which are used to reduce the degree of lattice mismatch in a quantum well, improve the lattice mismatch problem, and improve the recombination efficiency of carriers, thereby improving the quality of the epitaxial crystal, reducing the non-radiative recombination ability, and further improving the external quantum efficiency of the light-emitting diode and enhancing the performance of the light-emitting diode.

[0005] In a first aspect, the present application provides an epitaxial structure of an InGaN-based light-emitting diode, the epitaxial structure comprising a substrate, a light-emitting layer formed on the substrate, an N-type current spreading layer and a P-type current spreading layer formed on both sides of the light-emitting layer, and an electron blocking layer formed between the light-emitting layer and the P-type current spreading layer. The light-emitting layer comprises at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0≤y <x<1。

[0006] In some embodiments, the quantum well layer In x Ga 1-x The thickness of N ranges from 2nm to 10nm, and the quantum barrier layer In y Ga 1-y The thickness range of N is 3nm~15nm.

[0007] In some embodiments, each quantum barrier layer In y Ga 1-y N includes the first quantum barrier sublayer In y1 Ga1-y1 N and the sub-layer In of the second quantum barrier layer y2 Ga 1-y2 N, the sub-layer In of the first quantum barrier layer y1 Ga 1-y1 N and the sub-layer In of the second quantum barrier layer y2 Ga 1-y2 There is a GaN interlayer or an AlGaN interlayer provided in N.

[0008] In some embodiments, each quantum barrier layer In y Ga 1-y N includes at least two sub-layers of quantum barrier layers. Among the at least two sub-layers of quantum barrier layers, the value of y takes one of gradually increasing, gradually decreasing, increasing first and then decreasing, and decreasing first and then increasing.

[0009] In some embodiments, in adjacent sub-layers of quantum barrier layers, the change amount of the value of y is less than a preset threshold.

[0010] In some embodiments, if the light-emitting layer includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y takes one of maintaining stability, gradually increasing, gradually decreasing, increasing first and then decreasing, decreasing first and then increasing, or being alternately arranged.

[0011] In some embodiments, the epitaxial structure further includes a GaN layer, and the GaN layer is formed between the N-type current spreading layer and the light-emitting layer.

[0012] In this application, the light-emitting layer includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0 ≤ y < x < 1. The quantum well structure thus formed can still ensure that the emission wavelength of light remains unchanged. And because both the quantum well layer In x Ga 1- x N and the quantum barrier layer In y Ga 1-y N include indium, gallium, and nitrogen in their material compositions, the lattice mismatch is reduced, the lattice mismatch degree in the quantum well is decreased, the lattice quality is improved, and thus the compressive stress caused by the lattice mismatch is reduced, the piezoelectric polarization effect is weakened, which is beneficial to improving the external quantum efficiency.

[0013] In addition, at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga1-y The potential barrier formed by N can assist or inhibit the migration of carriers, effectively control the concentration of carriers in each quantum well, thereby reducing the compressive stress of the quantum well, and improve the recombination efficiency of carriers, thereby improving the quality of epitaxial crystals, reducing non-radiative recombination ability, and further improving the external quantum efficiency of light-emitting diodes and enhancing the performance of light-emitting diodes.

[0014] In a second aspect, the present application further provides a light emitting diode, which includes the epitaxial structure of the InGaN-based light emitting diode mentioned in any embodiment of the first aspect.

[0015] The light-emitting diode has the same beneficial effects as the above-mentioned epitaxial structure, the light-emitting efficiency is improved, and the performance is good, which will not be described in detail here.

[0016] In a third aspect, the present application further provides a method for preparing an epitaxial structure of an InGaN-based light-emitting diode, comprising the following steps S01 to S02:

[0017] Step S01: providing a substrate.

[0018] Step S02: preparing a light-emitting layer, an N-type current spreading layer and a P-type current spreading layer on both sides of the light-emitting layer, and an electron blocking layer between the light-emitting layer and the P-type current spreading layer on a substrate.

[0019] The light-emitting layer includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0≤y <x<1。

[0020] In some embodiments, preparing a light-emitting layer on a substrate includes:

[0021] Step 1: epitaxial formation of quantum well layer In x Ga 1-x N;

[0022] Step 2: epitaxial formation of quantum barrier layer In y Ga 1-y N;

[0023] Perform the above steps 1 and 2 at least once.

[0024] In some embodiments, the quantum barrier layer In is formed by epitaxy. y Ga 1-y N includes: epitaxially forming the first quantum barrier layer sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2N, and epitaxially form a GaN interlayer or an AlGaN interlayer between the first quantum barrier sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N.

[0025] In some embodiments, each time the quantum barrier layer In y Ga 1-y N is epitaxially formed, it includes: epitaxially forming at least two quantum barrier sublayers, and controlling the y value in at least two quantum barrier sublayers by controlling the gas flow rates of the In source gas, Ga source gas, and N source gas when epitaxially forming each quantum barrier sublayer, so that the value of y gradually increases, gradually decreases, increases first and then decreases, or decreases first and then increases.

[0026] In some embodiments, in adjacent quantum barrier sublayers, the change amount of the y value is less than a preset threshold.

[0027] In some embodiments, if the light-emitting layer includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N, and at least two times of epitaxially forming the quantum barrier layer In y Ga 1-y N, it includes: by controlling the gas flow rates of the In source gas, Ga source gas, and N source gas, so that in at least two quantum barrier layers In y Ga 1-y N formed by epitaxy, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y is maintained stable, gradually increases, gradually decreases, increases first and then decreases, decreases first and then increases, or is alternately set.

[0028] In the preparation method provided in this application, by optimizing the formation process of the light-emitting layer, the light-emitting layer includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N (where 0 ≤ y < x < 1), thereby forming an innovative epitaxial structure. The light-emitting layer formed based on this preparation method can ensure that the emission wavelength of light remains unchanged, and reduces the lattice mismatch degree in the quantum well, improves the lattice quality, reduces the compressive stress caused by lattice mismatch, weakens the piezoelectric polarization effect, and is beneficial to improving the external quantum efficiency. In addition, at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-yThe potential barrier formed by N can assist or inhibit the migration of carriers, effectively control the concentration of carriers in each quantum well, thereby reducing the compressive stress of the quantum well, and improve the recombination efficiency of carriers, thereby improving the quality of epitaxial crystals, reducing non-radiative recombination ability, and further improving the external quantum efficiency of light-emitting diodes and enhancing the performance of light-emitting diodes.

[0029] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 A schematic diagram of an epitaxial structure provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of the first light-emitting layer provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of the second light-emitting layer provided in the embodiment of the present application;

[0034] Figure 4 A schematic diagram of the structure of the third light-emitting layer provided in the embodiment of the present application;

[0035] Figure 5 A schematic diagram of the structure of the fourth light-emitting layer provided in an embodiment of the present application;

[0036] Figure 6 A schematic diagram of the structure of the fifth light-emitting layer provided in the embodiment of the present application;

[0037] Figure 7 A schematic diagram of the structure of the sixth light-emitting layer provided in an embodiment of the present application;

[0038] Figure 8 A schematic diagram of the structure of the seventh light-emitting layer provided in the embodiment of the present application;

[0039] Fig. 9 A schematic diagram of the structure of an eighth light-emitting layer provided in an embodiment of the present application;

[0040] Fig.10 A schematic diagram of the structure of a ninth light-emitting layer provided in an embodiment of the present application;

[0041] Fig.11 A schematic diagram of the structure of the tenth light-emitting layer provided in an embodiment of the present application;

[0042] Fig.12A schematic diagram of the structure of a light emitting diode provided in an embodiment of the present application;

[0043] Fig.13 A flow chart of a method for preparing an epitaxial structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0045] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0046] In the description of the present application, “plurality” means two or more.

[0047] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0048] When describing some embodiments, the expression "connected" and its derivatives may be used. The term "connected" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. The term "electrically connected" indicates, for example, that two or more components are in direct physical or electrical contact, and may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0049] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0050] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0051] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0052] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0053] At present, in the study of indium gallium nitride (InGaN)-based light-emitting diodes, it is found that it is difficult to form InGaN-based light-emitting diodes (especially red light-emitting diodes) with high external quantum efficiency. On the one hand, the growth of InGaN-based quantum wells with high indium components is usually carried out at a relatively low temperature (600-800°C). However, InGaN materials with high indium components tend to spontaneously decompose into indium nitride (InN) and gallium nitride (GaN) at this temperature. Increasing the temperature will cause the precipitation of indium due to the breaking of the In-N bond, resulting in poor crystal quality. On the other hand, as the indium component increases, the stress in the quantum well system increases due to the increase in lattice mismatch. The increased stress will be released through penetration dislocations, groove defects, etc., resulting in a decrease in lattice quality. The increased stress will also cause a larger polarization field, resulting in a more serious quantum confined Stark effect (QCSE), making the light-emitting diode less efficient.

[0054] In addition, since the electron mobility is greater than the hole mobility, the electron concentration is greater than the hole concentration, which will lead to different recombination pairs of carriers in each quantum well. In the current design of almost all quantum wells, the radiative recombination in each quantum well is not evenly divided among the quantum wells. Some quantum wells have wasted recombination space, and excessive recombination in some quantum wells will lead to non-radiative recombination such as Auger recombination, which will also make the efficiency of the light-emitting diode low.

[0055] In summary, in the related technology, the lattice mismatch between InGaN with high indium content and GaN is large, resulting in poor crystal quality of epitaxial structure, which in turn causes dislocation defects and QCSE effect, resulting in a decrease in external quantum efficiency. In addition, the unreasonable design of quantum well structure causes non-radiative recombination, resulting in a decrease in external quantum efficiency. The above two reasons make the luminous efficiency of InGaN-based red light-emitting diodes still at a low level.

[0056] The related art attempts to solve the above problems by regulating the epitaxial layer outside the quantum well have great limitations.

[0057] Based on this, the present application provides an epitaxial structure of an InGaN-based light-emitting diode, aiming to improve the problem of quantum well lattice mismatch by improving the design within the quantum well, thereby improving the efficiency of the light-emitting diode.

[0058] like Figure 1 As shown, Figure 1 A schematic structural diagram of an epitaxial structure provided in an embodiment of the present application.

[0059] The epitaxial structure 10 includes a substrate 11, a light-emitting layer 12 formed on the substrate 11, an N-type current spreading layer 13 and a P-type current spreading layer 14 formed on both sides of the light-emitting layer 12, and an electron blocking layer 15 formed between the light-emitting layer 12 and the P-type current spreading layer 14. The light-emitting layer 12 includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0≤y <x<1。

[0060] The material of the substrate 11 may include any one of silicon wafer, C-plane sapphire, nano-patterned sapphire, patterned sapphire, mica sheet or silicon carbide, and is preferably nano-patterned sapphire.

[0061] The N-type current spreading layer 13 and the P-type current spreading layer 14 are respectively located on both sides of the light emitting layer 12, preferably as follows Figure 1 As shown, the N-type current spreading layer 13 is located on a side of the light emitting layer 12 close to the substrate 11 , and the P-type current spreading layer 14 is located on a side of the light emitting layer 12 away from the substrate 11 .

[0062] To improve the lattice matching degree, exemplarily, as Figure 1 shown, a low-temperature buffer layer 16 and a preparation layer 17 can also be provided between the substrate 11 and the N-type current spreading layer 13.

[0063] To ensure good electrical conductivity, exemplarily, as Figure 1 shown, an electrode layer 18 is also provided on the side of the P-type current spreading layer 14 away from the substrate 11.

[0064] In the epitaxial structure 10 provided in this application, the light-emitting layer 12 includes at least a pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N. Compared with the related art, the well layers in the original quantum well system are retained to ensure that the emission wavelength of light remains unchanged, and a new quantum barrier layer In y Ga 1-y N is adopted, so that both the quantum barrier layer In y Ga 1-y N and the quantum well layer In x Ga 1-x N include indium, gallium, and nitrogen in their material components. The same elemental components are beneficial to reducing the lattice mismatch, reducing the lattice mismatch degree in the quantum well, improving the lattice quality, and further reducing the compressive stress caused by the huge lattice mismatch, thereby improving the lattice quality, weakening the piezoelectric polarization effect, and being beneficial to improving the external quantum efficiency.

[0065] In the above-mentioned quantum well layer In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, x and y respectively represent the atomic number ratios of indium elements, where 0 ≤ y < x < 1. Due to the difference in materials between the quantum well layer In x Ga 1-x N and the quantum barrier layer In y Ga 1-y N, their band gaps are different. The potential barrier formed by a pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N can prevent electrons (or holes) from escaping from the quantum well layer. From the perspective of carrier transport, under the forward bias of the epitaxial layer, the electron mobility is greater than the hole mobility. Therefore, it is necessary to reduce the hole passing potential barrier or suppress the electron overshoot.

[0066] In the embodiments of this application, by regulating the quantum barrier layer In y Ga 1-yThe proportion of indium in N, that is, the value of y, can be adjusted to adjust the barrier size. x Ga 1-x N and quantum barrier layer In y Ga 1-y N, through reasonable design, a periodically changing potential barrier can be formed. This periodic potential barrier design can assist or inhibit the migration of carriers and effectively control the concentration of carriers in each quantum well. Therefore, a reasonable periodic potential barrier design can reduce the compressive stress of the quantum well, improve the recombination efficiency of carriers, and improve the external quantum efficiency.

[0067] Furthermore, when the epitaxial structure 10 includes multiple pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, through reasonable design, a periodically changing energy band structure can be formed on the epitaxial structure 10, which is beneficial to further reduce the quantum well layer In x Ga 1-x N and quantum barrier layer In y Ga 1-y N's internal stress, and the concentration of carriers in the quantum barrier layer can also be effectively suppressed, thereby improving the external quantum efficiency.

[0068] For example, Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of the first light-emitting layer provided in an embodiment of the present application.

[0069] The light emitting layer 12 includes 6 pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where x = 0.32, y = 0.1. Based on the above periodic barrier design, the light-emitting layer 12 can reduce the compressive stress of the quantum well, while improving the recombination efficiency of carriers, reducing the non-radiative recombination ability, and improving the external quantum efficiency, thereby improving the performance of the light-emitting diode formed based on the structure.

[0070] To sum up, the epitaxial structure 10 provided in the embodiment of the present application can reduce the compressive stress of the quantum well, reduce the degree of lattice mismatch in the quantum well, improve the lattice mismatch problem, and improve the recombination efficiency of carriers, thereby improving the quality of the epitaxial crystal, reducing the non-radiative recombination ability, and then improving the external quantum efficiency of the light-emitting diode and improving the performance of the light-emitting diode.

[0071] In some embodiments, the quantum well layer In x Ga 1-xThe thickness of N ranges from 2nm to 10nm. For example, the quantum well layer In x Ga 1-x The thickness of N can be 2nm, 3nm, 4nm, 5nm...10nm. y Ga 1-y N thickness ranges from 3nm to 15nm, for example, the quantum barrier layer In y Ga 1-y The thickness of N can be 3nm, 4nm, 5nm, 6nm...15nm.

[0072] For example, Figure 2 In the light emitting layer 12 shown, the quantum well layer In x Ga 1-x N thickness is 3nm, quantum barrier layer In y Ga 1-y The thickness of N is 5 nm.

[0073] In some embodiments, each quantum barrier layer In y Ga 1-y N includes the first quantum barrier sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N, the first quantum barrier sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 A GaN interlayer or an AlGaN interlayer is provided in the N.

[0074] For example, taking the AlGaN interlayer as an example, Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of the second light-emitting layer provided in the embodiment of the present application. Wherein, y1=y2=0.1, the quantum barrier layer In y Ga 1-y The thickness of N is 5 nm. That is, the quantum barrier layer In y Ga 1-y N includes the first quantum barrier sublayer In 0.1 Ga 0.9 N (thickness 2nm), AlGaN interlayer (specific composition is Al 0.02 Ga 0.98 N, thickness 1nm), the second quantum barrier layer sublayer In 0.1 Ga 0.9 N (thickness is 2nm).

[0075] By providing a GaN interlayer or an AlGaN interlayer, electron overshoot caused by the reduction of the quantum barrier layer in the quantum well can be prevented, thereby reducing non-radiative recombination and improving luminous efficiency.

[0076] In some embodiments, each quantum barrier layer In y Ga 1-y N includes at least two quantum barrier layer sublayers, and in the at least two quantum barrier layer sublayers, the value of y is one of gradually increasing, gradually decreasing, first increasing and then decreasing, and first decreasing and then increasing.

[0077] For example, Figures 4 to 6 As shown, Figure 4 This is a schematic diagram of the structure of the third light-emitting layer provided in the embodiment of the present application. Figure 5 This is a schematic diagram of the structure of the fourth light-emitting layer provided in the embodiment of the present application, Figure 6 This is a schematic diagram of the structure of the fifth light-emitting layer provided in an embodiment of the present application.

[0078] Along the direction of hole injection, Figure 4 It indicates the step-by-step change of the potential barrier from high to low (that is, the value of y gradually increases). Figure 5 It indicates the step-by-step change of the potential barrier from low to high (that is, the value of y gradually decreases). Figure 6 It indicates a step-by-step change in which the potential barrier first increases and then decreases (that is, the value of y first decreases and then increases).

[0079] Based on the value of the atomic number ratio of the indium element, multiple quantum barrier sublayers are reasonably arranged to form a slow change between the quantum well layer and the quantum barrier layer, which can further reduce the internal stress of the quantum well layer and the quantum barrier layer. At the same time, the concentration of carriers in the quantum barrier layer can also be effectively suppressed, reducing non-radiative recombination.

[0080] In some embodiments, in adjacent quantum barrier layer sub-layers, the value change of y is less than a preset threshold.

[0081] Exemplarily, the preset threshold is 15%, that is, the change in the indium element composition between adjacent quantum barrier sublayers is less than 15%. The slow change between the quantum well layer and the quantum barrier layer will further reduce the compressive stress caused by the huge lattice mismatch, thereby improving the lattice quality and weakening the piezoelectric polarization effect. At the same time, after passing through the potential barrier, electrons or holes will be injected into the quantum well layer faster, and will not stay in the quantum barrier layer, which is conducive to increasing the carrier concentration in the quantum well layer.

[0082] For example, Figure 6 As shown, the quantum barrier layer In y Ga 1-yN is 5nm thick and includes 5 quantum barrier sublayers, each of which is 1nm thick. The quantum barrier sublayer group with the highest potential barrier is In 0.12 Ga 0.88 N, the change in indium element composition between adjacent quantum barrier sublayers is 1%.

[0083] In some embodiments, if the light emitting layer 12 includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1- y N, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y is one of maintaining stability, gradually increasing, gradually decreasing, first increasing and then decreasing, first decreasing and then increasing, or alternating settings.

[0084] For example, Figure 7 to Figure 11 As shown, Figure 7 This is a schematic diagram of the structure of the sixth light-emitting layer provided in the embodiment of the present application, Figure 8 This is a schematic diagram of the structure of the seventh light-emitting layer provided in the embodiment of the present application, Fig. 9 This is a schematic diagram of the structure of the eighth light-emitting layer provided in the embodiment of the present application, Fig.10 This is a schematic diagram of the structure of the ninth light-emitting layer provided in the embodiment of the present application. Fig.11 This is a schematic diagram of the structure of the tenth light-emitting layer provided in an embodiment of the present application.

[0085] Along the direction of hole injection, Figure 7 It indicates the step-by-step change of the potential barrier from high to low (that is, the value of y gradually increases). Figure 8 It indicates the step-by-step change of the potential barrier from low to high (that is, the value of y gradually decreases). Fig. 9 It indicates a step-wise change in which the potential barrier first increases and then decreases (that is, the value of y first decreases and then increases). Fig.10 It indicates a step-wise change in which the potential barrier first decreases and then increases (that is, the value of y first increases and then decreases). Fig.11 It indicates that the potential barrier height changes periodically (that is, the value of y is set alternately).

[0086] Due to the high electron mobility, the concentration of electrons near the electron blocking layer 15 will be higher than that far away from the electron blocking layer 15, and the hole mobility is low, so the concentration of holes near the electron blocking layer 15 will be higher than that far away from the electron blocking layer 15. This results in most carrier recombination locations being near the electron blocking layer 15, and other quantum wells are in a state of low recombination rate.

[0087] Quantum barrier layer In y Ga 1-yBased on the value of the atomic ratio of indium in N, the multiple pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y A reasonable arrangement of N can form a stepped or periodic barrier design, thereby assisting or inhibiting the migration of carriers and effectively controlling the concentration of carriers in each quantum well.

[0088] Preferably, Figure 8 or Fig. 9 As shown, in the process of electron migration, the electron blocking layer 15 is the real limit of electron overshoot, so the high-concentration electrons near the electron blocking layer 15 are affected by the quantum barrier layer In y Ga 1-y The influence of N is relatively small, while holes are easily affected by the quantum barrier In due to their slow mobility. y Ga 1-y N is an obstacle. Figure 8 or Fig. 9 The quantum barrier layer In y Ga 1-y The N arrangement reduces the potential barrier of hole transmission in the first few quantum wells, transfers part of the carriers originally recombined in the injection area to the inside of the quantum well, reduces non-radiative recombination such as Auger recombination, and improves the recombination efficiency.

[0089] In some embodiments, Figure 1 As shown, the epitaxial structure 10 also includes a GaN layer 19, which is formed between the N-type current spreading layer 13 and the light-emitting layer 12. On the one hand, the GaN layer 19 can reduce electron leakage, and on the other hand, it can form a good energy band structure with the light-emitting layer 12 to promote the radiative recombination of electrons and holes in the quantum well, improve the luminous efficiency, and reduce non-radiative recombination. In addition, the interface quality of the quantum well can be optimized through stress regulation to reduce the quantum confinement Stark effect caused by stress.

[0090] In a second aspect, the present application also provides a light emitting diode, such as Fig.12 As shown, Fig.12 A schematic diagram of the structure of a light emitting diode provided in an embodiment of the present application. The light emitting diode 20 includes the epitaxial structure 10 of the InGaN-based light emitting diode mentioned in any embodiment of the first aspect above, and also includes a second electrode 21. The electrode layer 18 and the second electrode 21 constitute two electrodes of the diode 20 for electrically connecting to a driving circuit.

[0091] The light emitting diode 20 formed based on the epitaxial structure 10 is configured by optimizing the design of the light emitting layer 12 so that the light emitting layer 12 includes at least one pair of quantum well layers In x Ga 1-xN and InGaN quantum barrier layers y Ga 1-y N, where 0 ≤ y < x < 1. The resulting quantum well structure can still ensure that the emission wavelength of light remains unchanged. Moreover, since both the In x Ga 1-x N quantum well layer and the In y Ga 1-y N quantum barrier layer include indium, gallium, and nitrogen in their material compositions, the lattice mismatch is reduced, the lattice mismatch degree within the quantum well is decreased, the lattice quality is improved, and thus the compressive stress caused by the lattice mismatch is reduced, the piezoelectric polarization effect is weakened, which is beneficial to improving the external quantum efficiency.

[0092] In addition, the potential barriers formed by at least one pair of In x Ga 1-x N quantum well layers and In y Ga 1-y N quantum barrier layers can assist or inhibit the migration of carriers, effectively control the carrier concentration in each quantum well, thereby reducing the compressive stress of the quantum well, while improving the carrier recombination efficiency, thus improving the quality of the epitaxial crystal, reducing the non-radiative recombination ability, and further improving the external quantum efficiency of the light-emitting diode 20 and enhancing the performance of the light-emitting diode 20.

[0093] Thirdly, the present application also provides a method for preparing an epitaxial structure of an InGaN-based light-emitting diode. As Fig.13 shown, Fig.13 FIG. is a flowchart of a method for preparing an epitaxial structure provided by an embodiment of the present application.

[0094] As Fig.13 shown, the preparation method includes the following steps S01 to step S02:

[0095] Step S01: Provide a substrate 11.

[0096] Step S02: Prepare a light-emitting layer 12, an N-type current spreading layer 13 and a P-type current spreading layer 14 located on both sides of the light-emitting layer 12, and an electron blocking layer 15 located between the light-emitting layer 12 and the P-type current spreading layer 14 on the substrate 11. The light-emitting layer 12 includes at least one pair of In x Ga 1-x N quantum well layers and In y Ga 1-y N quantum barrier layers, where 0 ≤ y < x < 1.

[0097] Exemplarily, to improve the lattice matching degree, in some embodiments, a low-temperature buffer layer 16 is first formed on the substrate 11. The material of the low-temperature buffer layer 16 may include at least one of AlN, GaN, or AlGaN, etc., and the thickness range is 5 nm to 500 nm. Preferably, the material of the low-temperature buffer layer 16 includes AlN, which is formed by magnetron sputtering epitaxy, with a thickness of 25 nm and a growth temperature of 530 °C.

[0098] After that, a preparation layer 17 is formed on the side of the low-temperature buffer layer 16 away from the substrate 11, and the thickness range is 0.5 μm to 5 μm. Preferably, the preparation layer 17 is formed by metalorganic chemical vapor deposition (MOCVD) epitaxy. The material of the preparation layer 17 includes ultra-thin gallium nitride (U-GaN), with a thickness of 2 μm and a growth temperature of 1060 °C.

[0099] Next, an N-type current spreading layer 13 is formed, and the thickness range is 1 μm to 10 μm. Preferably, the N-type current spreading layer 13 is formed by metalorganic chemical vapor deposition (MOCVD) epitaxy. The material of the N-type current spreading layer 13 includes N-type gallium nitride (N-GaN), with a thickness of 3 μm and a growth temperature of 1080 °C.

[0100] Then, a GaN layer 19 is formed by epitaxy. Preferably, the thickness of the GaN layer 19 is 5 nm.

[0101] After that, a light-emitting layer 12 is formed. The light-emitting layer 12 includes at least a pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N, where 0 ≤ y < x < 1. The thickness range of the quantum well layer In x Ga 1-x N is 2 nm to 10 nm, and the thickness range of the quantum barrier layer In y Ga 1-y N is 3 nm to 15 nm. Preferably, as Figure 2 shown, in the design of 6 pairs of quantum well structures, the thickness of the quantum well layer In x Ga 1-x N is 3 nm, and the thickness of the quantum barrier layer In y Ga 1-y N is 5 nm, x = 0.32, and y = 0.1.

[0102] Next, an electron blocking layer 15 is formed, and the thickness range is 5 nm to 500 nm. Preferably, a P-type electron blocking layer 15 is formed by metalorganic chemical vapor deposition (MOCVD) epitaxy. The material of the electron blocking layer 15 includes p-Al 0.15 Ga 0.85N, with a thickness of 28 nm and an Mg doping concentration of 5E18 / cm 3 .

[0103] Then, a P-type current spreading layer 14 is formed, with a thickness ranging from 5 nm to 500 nm. Preferably, the P-type current spreading layer 14 is epitaxially formed by metalorganic chemical vapor deposition (MOCVD). The material of the P-type current spreading layer 14 includes p-GaN, with a thickness of 100 nm and an Mg doping concentration of 2E19 / cm 3 .

[0104] After that, an electrode layer 18 is formed, with a thickness ranging from 10 nm to 200 nm. Preferably, the material of the electrode layer 18 includes indium tin oxide (ITO), which is formed by magnetron sputtering deposition, with a thickness of 60 nm.

[0105] Up to this point, an epitaxial structure 10 as shown in Figure 1 can be formed.

[0106] In the above preparation method, by optimizing the formation process of the light-emitting layer 12, the light-emitting layer 12 includes at least a pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N (where 0 ≤ y < x < 1), thus forming an innovative epitaxial structure 10. Based on this preparation method, the formed light-emitting layer 12 can ensure that the emission wavelength of light remains unchanged, and reduces the lattice mismatch degree in the quantum well, improves the lattice quality, reduces the compressive stress caused by lattice mismatch, weakens the piezoelectric polarization effect, and is beneficial to improving the external quantum efficiency. In addition, the potential barriers formed by at least a pair of quantum well layers In x Ga 1-x N and quantum barrier layers In y Ga 1-y N can assist or inhibit the migration of carriers, effectively control the carrier concentration in each quantum well, thereby reducing the compressive stress of the quantum well, while improving the carrier recombination efficiency, thus improving the epitaxial crystal quality, reducing the non-radiative recombination ability, and further improving the external quantum efficiency of the light-emitting diode and enhancing the performance of the light-emitting diode.

[0107] In some embodiments, the steps of preparing the light-emitting layer 12 on the substrate 11 include:

[0108] Step 1, epitaxially form a quantum well layer In x Ga 1-x N;

[0109] Step 2, epitaxially form a quantum barrier layer In y Ga 1-y N;

[0110] Perform the above steps 1 and 2 at least once.

[0111] Exemplarily, step 1 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 20sccm to 100sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum well layer In with a certain component ratio x Ga 1-x N.

[0112] Step 2 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 0.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain component ratio. y Ga 1-y N.

[0113] Repeat the above steps 1 and 2 for 5 more times to obtain Figure 2 The light emitting layer 12 is shown.

[0114] In the above preparation process, the reaction time and the gas flow rates of Ga source, In source and N source are controlled to control the quantum well layer In x Ga 1-x N and quantum barrier layer In y Ga 1-y The component ratio and thickness of N finally form the preset light-emitting layer 12.

[0115] In some embodiments, the quantum barrier layer In is formed by epitaxy. y Ga 1-y N includes: epitaxially forming the first quantum barrier layer sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N, and in the first quantum barrier sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N interlayer is epitaxially grown to form a GaN interlayer or an AlGaN interlayer.

[0116] Exemplarily, taking the AlGaN interlayer as an example, step 1 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 60sccm to 100sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 5min to 30min, thereby forming a quantum well layer In with a certain component ratio x Ga 1-x N.

[0117] Step 2 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 0.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 10min, thereby forming a first quantum barrier layer sublayer In with a certain composition ratio. y1 Ga 1-y1 N (its component ratio is In 0.1 Ga 0.9 N).

[0118] Step 3: Set the chamber temperature to 750°C to 950°C, introduce 1 sccm to 50 sccm of trimethyl gallium (TMGa) gas, 0.1 sccm to 20 sccm of trimethyl aluminum (TMAl) gas, and 100 sccm to 1500 sccm of ammonia (NH3), and maintain the reaction time for 0.5 min to 3 min, thereby forming an AlGaN interlayer (whose composition ratio is Al 0.02 Ga 0.98 N).

[0119] Step 4 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 0.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 10min, thereby forming a second quantum barrier layer sublayer In with a certain composition ratio. y2 Ga 1-y2 N (its component ratio is In 0.1 Ga 0.9 N).

[0120] Repeat the above steps 1 to 4 for 5 more times to obtain Figure 3 The light emitting layer 12 is shown.

[0121] In some embodiments, each time the quantum barrier layer In is formed by epitaxy,y Ga 1-y N includes: epitaxially forming at least two quantum barrier layer sublayers, and controlling the gas flow rates of In source gas, Ga source gas and N source gas when epitaxially forming each quantum barrier layer sublayer, controlling the y value in at least two quantum barrier layer sublayers, so that the value of y gradually increases, gradually decreases, first increases and then decreases, or first decreases and then increases.

[0122] For example, when multiple quantum barrier sub-layers are formed under the same other conditions, different potential barrier changes can be finally presented by controlling the gas flow rate of the In source gas. Figures 4 to 6 As shown, along the direction of hole injection, Figure 4 It indicates the step-by-step change of the potential barrier from high to low (that is, the value of y gradually increases). Figure 5 It indicates the step-by-step change of the potential barrier from low to high (that is, the value of y gradually decreases). Figure 6 It indicates a step-wise change in which the potential barrier first increases and then decreases (that is, the value of y first decreases and then increases).

[0123] Exemplarily, step 1 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 30sccm to 50sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time at 0.6min to 5min, thereby forming a first quantum barrier layer sublayer In with a certain component ratio y1 Ga 1-y1 N.

[0124] Step 2 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 10sccm to 40sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 0.6min to 5min, thereby forming a second quantum barrier layer sublayer In with a certain composition ratio. y2 Ga 1-y2 N.

[0125] Step three is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 2sccm to 20sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 0.6min to 5min, thereby forming a third quantum barrier sublayer In with a certain component ratio. y3 Ga 1-y3 N.

[0126] Step 4 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 1sccm to 15sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 0.6min to 5min, thereby forming a fourth quantum barrier layer sublayer In with a certain composition ratio. y4 Ga 1-y4 N.

[0127] Step 5 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 0.5sccm to 5sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time at 0.6min to 5min, thereby forming a fifth quantum barrier layer sublayer In with a certain composition ratio. y4 Ga 1-y4 N.

[0128] You can get Figure 4 The light emitting layer 12 is shown.

[0129] Similarly, according to the above preparation steps, by reasonably controlling the gas flow rates of In source gas, Ga source gas and N source gas, the following can be obtained: Figure 5-6 The light emitting layer 12 is shown.

[0130] It can be understood that due to the step change of the quantum barrier layer, after the light-emitting layer 12 is formed, the design of the electron blocking layer 15 can also be based on the indium element ratio of the quantum barrier layer at the contact surface with the light-emitting layer 12, and set a corresponding gradient electron blocking barrier to reduce internal stress.

[0131] In some embodiments, in adjacent quantum barrier layer sub-layers, the value change of y is less than a preset threshold.

[0132] For example, under the same conditions, by controlling the gas flow rate of the In source gas (ie, trimethylindium), the value variation of y in adjacent quantum barrier sublayers can be regulated. Preferably, the preset threshold is 15%.

[0133] Exemplarily, by controlling the gas flow rate of the In source gas (ie, trimethylindium), the following is formed: Figure 6 The light-emitting layer 12 shown in FIG. y Ga 1-y N is 5nm thick and includes 5 quantum barrier sublayers, each of which is 1nm thick. The quantum barrier sublayer group with the highest potential barrier is In 0.12 Ga0.88 N, the change in indium element composition between adjacent quantum barrier sublayers is 1%.

[0134] By controlling the change in the indium element composition between adjacent quantum barrier sublayers to be less than a preset threshold, the change between the quantum well layer and the quantum barrier layer can be made slower. The slow change between the quantum well layer and the quantum barrier layer will further reduce the compressive stress caused by the huge lattice mismatch, thereby improving the lattice quality and weakening the piezoelectric polarization effect. At the same time, after passing through the potential barrier, electrons or holes will be injected into the quantum well layer faster, and will not stay in the quantum barrier layer, which is conducive to increasing the carrier concentration in the quantum well layer.

[0135] In some embodiments, if the light-emitting layer includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, at least twice epitaxy to form quantum barrier layer In y Ga 1-y N, including: by controlling the gas flow rates of In source gas, Ga source gas and N source gas, at least two quantum barrier layers In formed by epitaxy are formed. y Ga 1-y N, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y is one of maintaining stability, gradually increasing, gradually decreasing, first increasing and then decreasing, first decreasing and then increasing, or alternating settings.

[0136] For example, in each pair of quantum well layers In x Ga 1-x When the material composition of N is the same, the quantum barrier layer In in each pair is formed. y Ga 1-y N, the gas flow rate of the In source gas can be controlled to make each pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N forms different potential barriers. For example, Figure 7 to Figure 11 As shown, along the direction of hole injection, Figure 7 It indicates the step-by-step change of the potential barrier from high to low (that is, the value of y gradually increases). Figure 8 It indicates the step-by-step change of the potential barrier from low to high (that is, the value of y gradually decreases). Fig. 9 It indicates a step-wise change in which the potential barrier first increases and then decreases (that is, the value of y first decreases and then increases). Fig.10 It indicates a step-wise change in which the potential barrier first decreases and then increases (that is, the value of y first increases and then decreases). Fig.11It indicates that the potential barrier height changes periodically (that is, the value of y is set alternately).

[0137] Exemplarily, step 1 is: setting the chamber temperature at 650°C to 950°C, introducing 10sccm to 90sccm of trimethylgallium (TMGa) gas, 20sccm to 100sccm of trimethylindium (TMIn) gas, and 200sccm to 2000sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum well layer In with a certain component ratio x Ga 1-x N.

[0138] Step 2 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 7sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain composition ratio. y Ga 1-y N.

[0139] At this point, the first pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N.

[0140] Step three is the same as step one.

[0141] Step 4 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 5.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain composition ratio. y Ga 1-y N.

[0142] At this point, the second pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N.

[0143] Step 5 is the same as step 1.

[0144] Step 6: Set the chamber temperature at 650°C to 950°C, introduce 20sccm to 100sccm of trimethylgallium (TMGa) gas, 4sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), and maintain the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain composition ratio. y Ga 1-y N.

[0145] At this point, the third pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N.

[0146] Step seven is the same as step one.

[0147] Step eight is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 3.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain composition ratio. y Ga 1-y N.

[0148] At this point, the fourth pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N.

[0149] Step nine is the same as step one.

[0150] Step 10 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 2sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain component ratio. y Ga 1-y N.

[0151] At this point, the fifth pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N.

[0152] The operation of step 11 is the same as that of step 1.

[0153] Step 12 is: setting the chamber temperature at 650°C to 950°C, introducing 20sccm to 100sccm of trimethylgallium (TMGa) gas, 0.5sccm to 50sccm of trimethylindium (TMIn) gas, and 100sccm to 1500sccm of ammonia (NH3), maintaining the reaction time for 1min to 20min, thereby forming a quantum barrier layer In with a certain component ratio. y Ga 1-y N.

[0154] At this point, the sixth pair of quantum well layers In is formed. x Ga 1-x N and quantum barrier layer In y Ga 1-y N, we can get Figure 7 The light emitting layer 12 is shown.

[0155] Similarly, according to the above preparation steps, by reasonably controlling the gas flow rates of In source gas, Ga source gas and N source gas, the following can be obtained: Figure 8 to Figure 11 The light emitting layer 12 is shown.

[0156] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can think of within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An epitaxial structure of an InGaN-based light-emitting diode, characterized in that: include: substrate; a light emitting layer formed on the substrate; An N-type current spreading layer and a P-type current spreading layer are formed on both sides of the light-emitting layer; An electron blocking layer formed between the light emitting layer and the P-type current spreading layer; Wherein, the light-emitting layer includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0≤y <x<1。 2. The epitaxial structure according to claim 1, characterized in that: The quantum well layer In x Ga 1-x N thickness ranges from 2nm to 10nm, and the quantum barrier layer In y Ga 1-y The thickness range of N is 3nm~15nm.

3. The epitaxial structure according to claim 1, characterized in that: Each of the quantum barrier layers In y Ga 1-y N includes the first quantum barrier sublayer In y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N, the first quantum barrier layer sublayer In y1 Ga 1- y1 N and the second quantum barrier layer sublayer In y2 Ga 1-y2 A GaN interlayer or an AlGaN interlayer is provided in the N.

4. The epitaxial structure according to claim 1, characterized in that: Each of the quantum barrier layers In y Ga 1-y N includes at least two quantum barrier layer sublayers, in which the value of y is one of gradually increasing, gradually decreasing, first increasing and then decreasing, and first decreasing and then increasing.

5. The epitaxial structure according to claim 4, characterized in that: In adjacent quantum barrier layer sublayers, the value change of y is less than a preset threshold.

6. The epitaxial structure according to any one of claims 1 to 5, characterized in that: If the light-emitting layer includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y is one of maintaining stability, gradually increasing, gradually decreasing, first increasing and then decreasing, first decreasing and then increasing, or alternating settings.

7. The epitaxial structure according to claim 6, characterized in that: Also includes: The GaN layer is formed between the N-type current spreading layer and the light emitting layer.

8. A light emitting diode, characterized in that: The invention comprises the epitaxial structure of the InGaN-based light-emitting diode as claimed in any one of claims 1 to 7.

9. A method for preparing an epitaxial structure of an InGaN-based light-emitting diode, characterized in that: include: providing a substrate; A light-emitting layer, an N-type current spreading layer and a P-type current spreading layer located on both sides of the light-emitting layer, and an electron blocking layer located between the light-emitting layer and the P-type current spreading layer are prepared on the substrate; Wherein, the light-emitting layer includes at least one pair of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, where 0≤y <x<1。 10. The preparation method according to claim 9, characterized in that: Preparing a light-emitting layer on the substrate, comprising: Step 1: epitaxial formation of quantum well layer In x Ga 1-x N; Step 2: epitaxial formation of quantum barrier layer In y Ga 1-y N; Perform the above steps 1 and 2 at least once.

11. The preparation method according to claim 10, characterized in that: The epitaxial formation of quantum barrier layer In y Ga 1-y N, including: The first quantum barrier layer In is formed by epitaxy. y1 Ga 1-y1 N and the second quantum barrier sublayer In y2 Ga 1-y2 N, and in the first quantum barrier layer sublayer In y1 Ga 1-y1 N and the second quantum barrier layer sublayer In y2 Ga 1-y2 N interlayer is epitaxially grown to form a GaN interlayer or an AlGaN interlayer.

12. The preparation method according to claim 10, characterized in that: Each time the quantum barrier layer In is formed by epitaxy y Ga 1- y N, including: At least two quantum barrier sublayers are formed epitaxially, and the gas flow rates of In source gas, Ga source gas and N source gas are controlled when each quantum barrier sublayer is formed epitaxially to control the value of y in the at least two quantum barrier sublayers so that the value of y increases gradually, decreases gradually, increases first and then decreases, or decreases first and then increases.

13. The preparation method according to claim 12, characterized in that: In adjacent quantum barrier layer sublayers, the value change of y is less than a preset threshold.

14. The preparation method according to any one of claims 9 to 13, characterized in that: If the light-emitting layer includes at least two pairs of quantum well layers In x Ga 1-x N and quantum barrier layer In y Ga 1-y N, epitaxially forming the quantum barrier layer In at least twice y Ga 1-y N, including: By controlling the gas flow rates of the In source gas, the Ga source gas and the N source gas, the at least two quantum barrier layers In formed by epitaxy are y Ga 1-y N, in the direction from the N-type current spreading layer to the electron blocking layer, the value of y is one of maintaining stability, gradually increasing, gradually decreasing, first increasing and then decreasing, first decreasing and then increasing, or alternating settings.

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