An epitaxial structure for a light-emitting diode, the light-emitting diode and its fabrication method

Abstract

This invention relates to the field of semiconductor technology, specifically disclosing an epitaxial structure for a light-emitting diode (LED), the LED itself, and a method for fabricating the same. The epitaxial structure includes a substrate and an epitaxial layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer in the epitaxial layer, and this dislocation shielding layer fills and merges the V-shaped pits on the active layer. The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer, and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes periodically alternating two-dimensional AlGaN layers and two-dimensional Mg and H co-doped InGaN layers. The boron (B) content in the three-dimensional BAlN layer decreases along the epitaxial direction. In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layers increases layer by layer with the accumulation of the number of periods. This invention can effectively improve the luminous efficiency and reliability of the LED.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an epitaxial structure for a light-emitting diode, a light-emitting diode, and a method for fabricating the same. Background Technology

[0002] Light-emitting diodes (LEDs) are the fourth generation of solid-state lighting sources, characterized by their small size, low operating voltage, fast response speed, long lifespan, and high luminous quality. They are widely used in various fields of production and daily life, including lighting, transportation, agriculture, and medicine. However, the limited luminous efficiency of existing LEDs restricts their further development.

[0003] Currently, the three-dimensional pn junction caused by the V-shaped pit is considered one of the key factors in improving luminous efficiency. Therefore, how to fabricate this pn junction well is very important for silicon-based gallium nitride LEDs. The performance of the pn junction can be affected by factors such as material quality and the pn junction interface. How to utilize it to maximize its effect is worthy of in-depth research.

[0004] It is currently believed that retaining an appropriate number of V-shaped pits in a multi-quantum-well layer can not only encourage holes to enter the plateau quantum well through the sidewall quantum wells, increasing the number of injected holes, but also increase the depth of hole injection into the n-GaN layer, improving the uniformity of hole distribution in the quantum well region. However, since V-shaped pits are generated along the line dislocations in the bottom layer, and line dislocations act as nonradiative recombination centers for charge carriers, this leads to increased nonradiative recombination, increased leakage current, and decreased electrical performance of the light-emitting diode. This makes it difficult to achieve high luminous efficiency by simply retaining V-shaped pits in a multi-quantum-well layer. Summary of the Invention

[0005] The purpose of this invention is to provide a light-emitting diode epitaxial structure, a light-emitting diode, and a method for fabricating the same, in light of the existing technology.

[0006] This invention deposits a dislocation shielding layer on an active layer with V-shaped pits. By utilizing the interaction between the multilayer material layers in the dislocation shielding layer and the V-shaped pit structure, it effectively reduces problems such as carrier capture by defects, increased non-radiative recombination, and increased leakage current caused by the V-shaped pits in the active layer, thereby effectively improving the overall luminous efficiency and reliability of the light-emitting diode.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] First, the present invention provides an epitaxial structure for a light-emitting diode, including a substrate and an epitaxial layer. The epitaxial layer includes a buffer layer, an undoped GaN layer, an N-type layer, an active layer, an electron blocking layer, and a P-type layer grown sequentially along the epitaxial direction. A V-shaped pit is formed from the N-type layer to the active layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer, and the dislocation shielding layer fills and merges the V-shaped pit on the active layer.

[0009] The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a periodically alternating two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer.

[0010] The content of the B component in the three-dimensional BAlN layer decreases along the epitaxial direction.

[0011] In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the accumulation of the number of periods.

[0012] In some embodiments, the content of the B component in the three-dimensional BAlN layer is 0.01~0.5.

[0013] In some embodiments, the Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is greater than the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer; and / or,

[0014] The Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer is 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 The Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is 1×10⁻⁶. 20 cm -3 ~1×10 21 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 .

[0015] In some embodiments, the Mg doping concentration of the two-dimensional Mg, H co-doped InGaN layer in the i-th period is N. iThe Mg doping concentration of the two-dimensional Mg, H co-doped InGaN layer in the (i+1)th period is N. i+1 where i is a positive integer, and 101%*N i ≤N i+1 ≤150%*N i .

[0016] In some embodiments, the growth atmosphere of the three-dimensional BaAlN layer and the two-dimensional AlN layer is N2 and NH3, and the flow rate ratio of N2 to NH3 is 1:1~10.

[0017] The growth atmosphere of the three-dimensional Mg and H co-doped AlInGaN layer and the two-dimensional Mg and H co-doped InGaN layer is N2, H2 and NH3, and the flow rate ratio of N2, H2 and NH3 is 1:1~10:1~10.

[0018] In some embodiments, the growth pressure of the three-dimensional BAlN layer and the growth pressure of the three-dimensional Mg,H co-doped AlInGaN layer are both greater than the growth pressure of the two-dimensional AlN layer and the growth pressure of the two-dimensional superlattice layer; and / or,

[0019] The growth pressure of the three-dimensional BAlN layer is 300 torr to 600 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer is 300 torr to 600 torr, the growth pressure of the two-dimensional AlN layer is 50 torr to 300 torr, and the growth pressure of the two-dimensional superlattice layer is 50 torr to 300 torr.

[0020] In some embodiments, the thicknesses of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg,H co-doped AlInGaN layer, and the two-dimensional superlattice layer increase sequentially; and / or,

[0021] The thickness of the three-dimensional BAlN layer is 1 nm to 10 nm, the thickness of the two-dimensional AlN layer is 1 nm to 10 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 1 nm to 100 nm, and the thickness of the two-dimensional superlattice layer is 1 nm to 200 nm.

[0022] In some embodiments, within the same period of the two-dimensional superlattice layer, the thickness ratio of the two-dimensional AlGaN layer to the two-dimensional Mg,H co-doped InGaN layer is 1:1~10; or,

[0023] In the same period of the two-dimensional superlattice layer, the thickness of the two-dimensional AlGaN layer is less than the thickness of the two-dimensional Mg, H co-doped InGaN layer.

[0024] Secondly, the present invention also provides a method for fabricating a light-emitting diode epitaxial structure, comprising:

[0025] Provide substrate;

[0026] A buffer layer and an undoped GaN layer are sequentially grown on the substrate.

[0027] An N-type layer with V-shaped pits is grown on the undoped GaN layer;

[0028] An active layer is grown on the N-type layer, and the active layer forms a V-shaped pit at the corresponding position of the V-shaped pit in the N-type layer.

[0029] A dislocation shielding layer is grown on the active layer, and the dislocation shielding layer fills and merges the V-shaped pits on the active layer;

[0030] An electron blocking layer and a P-type layer are sequentially grown on the dislocation shielding layer;

[0031] The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer grown periodically and alternately.

[0032] The content of the B component in the three-dimensional BAlN layer decreases along the epitaxial direction.

[0033] In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the accumulation of the number of periods.

[0034] Furthermore, the present invention also provides a light-emitting diode, comprising the above-described light-emitting diode epitaxial structure; or,

[0035] The above-mentioned method for fabricating an epitaxial structure of a light-emitting diode includes an epitaxial structure of a light-emitting diode.

[0036] The beneficial effects of this invention are as follows:

[0037] In this invention, the V-shaped pits begin in the N-type layer and extend to the entire active layer. Since the V-shaped pits begin before the active layer is deposited, they can initially shield dislocations. The extension of the V-shaped pits to the entire active layer can increase the number of holes injected and increase the depth of hole injection towards the N-type layer, thereby increasing the hole concentration of the quantum well near the N-type layer and improving the uniformity of hole distribution in the quantum well region.

[0038] Based on this, a dislocation shielding layer consisting of a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg, H co-doped AlInGaN layer, and a two-dimensional superlattice layer is deposited on the active layer to fill and merge the V-shaped pits on the active layer. Specifically:

[0039] First, a three-dimensional BAlN layer grown in a three-dimensional growth mode is deposited. Because the lattice constant of BAlN is smaller than that of GaN material layer, a dense material layer can be formed at the bottom of the V-shaped pit, which blocks the upward extension of the dislocations in the bottom layer. The three-dimensional island structure is used to twist the direction of dislocation extension. In addition, the B component content of the three-dimensional BAlN layer decreases along the epitaxial direction, which is conducive to improving its lattice fit with the subsequent two-dimensional AlN layer.

[0040] Next, a two-dimensional AlN layer grown in a two-dimensional growth mode is deposited to annihilate the dislocations twisted in the three-dimensional BAlN layer, further blocking the upward extension of dislocation defects, improving the crystal quality of the subsequently deposited epitaxial material, reducing the probability of charge carriers being trapped by defects, and reducing the probability of nonradiative recombination inside the V-shaped pit.

[0041] Subsequently, a three-dimensional Mg and H co-doped AlInGaN layer, grown in a three-dimensional growth mode, is deposited. Compared to a two-dimensional material layer, the three-dimensional material layer can fit more closely with the V-shaped pit, reducing interface defects. At the same time, the AlInGaN material layer can reduce the polarization effect, further increasing the probability of hole injection from the sidewall of the V-shaped pit. Mg and H are co-doped in the AlInGaN material layer, and the effective doping of Mg is improved by appropriate H doping (high hole concentration is obtained after subsequent annealing activation). Compared to the method of depositing a Mg-doped material layer on the epitaxial layer without V-shaped pits in the light-emitting layer, this method of depositing a Mg and H co-doped material layer on the active layer with V-shaped pits can better improve the hole injection efficiency through the synergistic effect of structure and material, further increasing the hole concentration of the quantum well near the N-type layer and improving the overall carrier recombination efficiency of the active layer.

[0042] Furthermore, a two-dimensional superlattice layer is deposited. Through the periodic alternating growth of two-dimensional AlGaN layers and two-dimensional Mg and H co-doped InGaN layers, V-shaped pits are filled, forming a smooth and high-quality epitaxial layer surface, effectively reducing leakage channels. Specifically, Mg and H co-doping is performed only in the InGaN layer, while the AlGaN layer remains undoped. This leverages the shallower Mg acceptor level in the InGaN layer to achieve higher hole activation efficiency. Moreover, the Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer increases layer by layer with each period, avoiding excessively high Mg doping concentration in a single layer that could lead to a decrease in crystal quality. Thus, a high hole concentration is achieved while maintaining good crystal quality. The periodic stacking of the two-dimensional AlGaN layer and the two-dimensional Mg and H co-doped InGaN layer alleviates stress and works synergistically with the three-dimensional Mg and H co-doped AlInGaN layer to optimize the hole transport path, further improving the uniformity and transport efficiency of the hole injection active layer.

[0043] Therefore, this invention effectively reduces problems such as carrier capture by defects, increased nonradiative recombination, and increased leakage current caused by the V-shaped pits in the active layer by depositing a dislocation shielding layer on the active layer with the cooperation between the multilayer material layers in the dislocation shielding layer and the V-shaped pit structure, thereby effectively improving the overall luminous efficiency and reliability of the light-emitting diode. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of a light-emitting diode epitaxial structure according to an embodiment of the present invention.

[0045] Figure 2 This is a schematic diagram of the structure of the dislocation shielding layer according to an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0047] First, see Figure 1 and Figure 2 As shown, the present invention provides an epitaxial structure for a light-emitting diode, including a substrate 1 and an epitaxial layer. The epitaxial layer includes a buffer layer 2, an undoped GaN layer 3, an N-type layer 4, an active layer 5, an electron blocking layer 7, and a P-type layer 8 grown sequentially along the epitaxial direction. V-shaped pits are formed from the N-type layer 4 to the active layer 5. A dislocation shielding layer 6 is provided between the active layer 5 and the electron blocking layer 7, and the dislocation shielding layer 6 fills and merges the V-shaped pits on the active layer 5.

[0048] The dislocation shielding layer 6 includes a three-dimensional BAlN layer 61, a two-dimensional AlN layer 62, a three-dimensional Mg and H co-doped AlInGaN layer 63 and a two-dimensional superlattice layer 64 grown sequentially along the epitaxial direction. The two-dimensional superlattice layer 64 includes a two-dimensional AlGaN layer 641 and a two-dimensional Mg and H co-doped InGaN layer 642 grown periodically and alternately.

[0049] The content of B component in the three-dimensional BAlN layer 61 decreases along the epitaxial direction;

[0050] In the two-dimensional superlattice layer 64, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in each period increases layer by layer with the accumulation of the number of periods.

[0051] In the two-dimensional superlattice layer 64, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in each period increases progressively with the number of periods. This means that in the two-dimensional superlattice layer 64, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in the i-th period is N. i The Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in the (i+1)th period is N. i+1 , where i is a positive integer, and N i+1 >N i .

[0052] The substrate 1 can be any one of sapphire substrate, silicon carbide substrate, silicon substrate, gallium nitride substrate, and zinc oxide substrate, but is not limited to this.

[0053] In this invention, the V-shaped pits begin in the N-type layer 4 and extend to the entire active layer 5. Since the V-shaped pits begin before the deposition of the active layer 5, they can initially shield dislocations. The extension of the V-shaped pits to the entire active layer 5 can increase the number of holes injected and increase the depth of hole injection towards the N-type layer 4, thereby increasing the hole concentration of the quantum well near the N-type layer 4 and improving the uniformity of hole distribution in the quantum well region.

[0054] Based on this, a dislocation shielding layer 6, consisting of a three-dimensional BAlN layer 61, a two-dimensional AlN layer 62, a three-dimensional Mg, H co-doped AlInGaN layer 63, and a two-dimensional superlattice layer 64, is deposited on the active layer 5 to fill and merge the V-shaped pits on the active layer 5. Specifically:

[0055] First, a three-dimensional BAlN layer 61 grown in a three-dimensional growth mode is deposited. Because the lattice constant of BAlN is smaller than that of GaN material layer, a dense material layer can be formed at the bottom of the V-shaped pit to block the upward extension of the dislocations in the bottom layer. The three-dimensional island structure is used to twist the direction of dislocation extension. In addition, the B component content of the three-dimensional BAlN layer 61 decreases along the epitaxial direction, which is conducive to improving the lattice fit between it and the subsequent two-dimensional AlN layer 62.

[0056] Next, a two-dimensional AlN layer 62 grown in a two-dimensional growth mode is deposited to annihilate the dislocations twisted in the three-dimensional BAlN layer 61, further blocking the upward extension of dislocation defects, improving the crystal quality of the subsequently deposited epitaxial material, reducing the probability of charge carriers being trapped by defects, and reducing the non-radiative recombination probability inside the V-shaped pit.

[0057] Subsequently, a three-dimensional Mg and H co-doped AlInGaN layer 63, grown in a three-dimensional growth mode, is deposited. Compared with a two-dimensional material layer, the three-dimensional material layer can fit more closely with the V-shaped pit, reducing interface defects. At the same time, the AlInGaN material layer can reduce the polarization effect, further increasing the probability of hole injection from the sidewall of the V-shaped pit. Mg and H are co-doped in the AlInGaN material layer, and the effective doping of Mg is improved by an appropriate amount of H doping (high hole concentration is obtained after subsequent annealing activation). Compared with the method of depositing a Mg-doped material layer on the epitaxial layer without V-shaped pits in the light-emitting layer, this method of depositing a Mg and H co-doped material layer on the active layer 5 with V-shaped pits can better improve the hole injection efficiency through the synergistic cooperation of structure and material, further increasing the hole concentration of the quantum well near the N-type layer 4, and improving the overall carrier recombination efficiency of the active layer 5.

[0058] Furthermore, a two-dimensional superlattice layer 64 is deposited. Through the periodically alternating growth of two-dimensional AlGaN layers 641 and two-dimensional Mg and H co-doped InGaN layers 642, V-shaped pits are filled, forming a smooth and high-quality epitaxial layer surface, effectively reducing leakage channels. Specifically, Mg and H co-doping is performed only in the InGaN material layer, while the AlGaN material layer remains undoped. This leverages the shallower Mg acceptor level in the InGaN material layer to achieve higher hole activation efficiency. Moreover, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layers 642 increases layer by layer with the number of cycles, avoiding excessively high Mg doping concentration in a single layer that could lead to a decrease in crystal quality. Thus, a high hole concentration is achieved while maintaining good crystal quality. The periodic stacking of the two-dimensional AlGaN layers 641 and 642 alleviates stress and works synergistically with the three-dimensional Mg and H co-doped AlInGaN layer 63 to optimize the hole transport path, further improving the uniformity and transport efficiency of the hole injection active layer 5.

[0059] Therefore, by depositing a dislocation shielding layer 6 on the active layer 5 with V-shaped pits, the present invention effectively reduces the problems caused by the V-shaped pits in the active layer 5, such as carrier capture by defects, increased non-radiative recombination, and increased leakage current, by utilizing the cooperation between the multilayer material layers in the dislocation shielding layer 6 and the V-shaped pit structure. This effectively improves the overall luminous efficiency and reliability of the light-emitting diode.

[0060] In some embodiments, the B component content in the three-dimensional BAlN layer 61 is 0.01~0.5, that is, B x Al 1-x N, x is 0.01~0.5.

[0061] For example, the content of component B in the three-dimensional BAlN layer 61 may be 0.01, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48 or 0.5, but is not limited thereto.

[0062] When the content of B component in the three-dimensional BAlN layer 61 is too low, the dislocation shielding effect is weak. When the content of B component in the three-dimensional BAlN layer 61 is too high, the lattice mismatch between the three-dimensional BAlN layer 61 and its adjacent material layers increases sharply, and the defect density increases easily.

[0063] In some embodiments, preferably, the Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer 642 is greater than the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer 63. On the one hand, a doping concentration gradient can be formed, and the diffusion effect generated by the concentration gradient further promotes the efficient injection of holes into the active layer 5; on the other hand, given that the three-dimensional material layer in the three-dimensional growth mode has higher requirements for crystal quality, using the three-dimensional Mg, H co-doped AlInGaN layer 63 with a relatively low Mg doping concentration is beneficial to improving its adhesion to the V-shaped pit and reducing interface defects.

[0064] In some embodiments, the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer 63 is 1 × 10⁻⁶. 19 cm -3 ~1×10 20 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 The Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer 642 is 1×10⁻⁶. 20 cm -3 ~1×10 21 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 .

[0065] For example, the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer 63 can be 1×10⁻⁶. 19 cm -3 2×10 19 cm -3 3×10 19 cm -3 4×10 19 cm -3 5×10 19 cm -3 6×10 19 cm -3 7×10 19 cm -3 8×10 19 cm -3 9×10 19 cm -3 Or 1×10 20 cm -3 However, it is not limited to this; the H doping concentration can be 1×10⁻⁶. 16 cm -3 2×10 16 cm -3 3×10 16 cm -3 4×10 16 cm -3 5×10 16 cm -3 6×10 16 cm -3 7×10 16 cm -3 8×10 16 cm -3 9×10 16 cm -3 1×10 17 cm -3 2×10 17 cm -3 5×10 17 cm -3 8×10 17 cm -3 Or 1×10 18 cm -3 However, it is not limited to this.

[0066] For example, the Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer 642 can be 1×10⁻⁶. 20 cm -3 2×10 20 cm -3 3×10 20 cm -34×10 20 cm -3 5×10 20 cm -3 6×10 20 cm -3 7×10 20 cm -3 8×10 20 cm -3 9×10 20 cm -3 Or 1×10 21 cm -3 However, it is not limited to this; the H doping concentration can be 1×10⁻⁶. 16 cm -3 2×10 16 cm -3 3×10 16 cm -3 4×10 16 cm -3 5×10 16 cm -3 6×10 16 cm -3 7×10 16 cm -3 8×10 16 cm -3 9×10 16 cm -3 Or 1×10 17 cm -3 However, it is not limited to this; the H doping concentration can be 1×10⁻⁶. 16 cm -3 2×10 16 cm -3 3×10 16 cm -3 4×10 16 cm -3 5×10 16 cm -3 6×10 16 cm -3 7×10 16 cm -3 8×10 16 cm -3 9×10 16 cm -3 1×10 17 cm -3 2×10 17 cm -3 5×10 17 cm -3 8×10 17cm -3 Or 1×10 18 cm -3 However, it is not limited to this.

[0067] In some embodiments, in the two-dimensional superlattice layer 64, the Mg doping concentration of the two-dimensional Mg, H co-doped InGaN layer 642 in the i-th period is N. i The Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in the (i+1)th period is N. i+1 where i is a positive integer, and 101%*N i ≤N i+1 ≤150%*N i .

[0068] That is, as the number of cycles of the two-dimensional superlattice layer 64 increases, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in a certain cycle increases by 1% to 50% compared to the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in the previous cycle. Among them, the increase in Mg doping concentration should not be too high, otherwise it will easily lead to crystal quality degradation and a decrease in hole activation rate.

[0069] For example, N i+1 It can be 101%*N i 105%*N i 108%*N i 110%*N i 115%*N i 120%*N i 125%*N i 130%*N i 135%*N i 140%*N i 145%*N i Or 150%*N i However, it is not limited to this.

[0070] In some embodiments, the number of periods of the two-dimensional superlattice layer 64 is 1 to 20, preferably 8 to 12.

[0071] In some embodiments, the growth atmosphere of the three-dimensional BaAlN layer 61 and the two-dimensional AlN layer 62 is N2 and NH3, and the flow rate ratio of N2 to NH3 is 1:1~10.

[0072] The growth atmospheres for the three-dimensional Mg and H co-doped AlInGaN layer 63 and the two-dimensional Mg and H co-doped InGaN layer 642 are N2, H2 and NH3, and the flow rates of N2, H2 and NH3 are 1:1~10:1~10.

[0073] For example, in the growth atmosphere of the three-dimensional BaAlN layer 61 and the two-dimensional AlN layer 62, the flow ratio of N2 to NH3 can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited thereto.

[0074] For example, in the growth atmosphere of the three-dimensional Mg and H co-doped AlInGaN layer 63 and the two-dimensional Mg and H co-doped InGaN layer 642, the flow ratio of N2, H2 and NH3 can be 1:1:1, 1:2:1, 1:2:2, 1:2:5, 1:2:10, 1:5:2, 1:5:5, 1:5:8, 1:5:10, 1:10:1, 1:10:2, 1:10:5, 1:10:8, 1:10:10, but is not limited to these.

[0075] In some embodiments, preferably, the growth pressure of the three-dimensional BAlN layer 61 and the three-dimensional Mg, H co-doped AlInGaN layer 63 are both greater than the growth pressure of the two-dimensional AlN layer 62 and the two-dimensional superlattice layer 64. The relatively higher growth pressure of the three-dimensional material layers helps reduce the line defect density after twisting and merging, thus improving crystal quality; the relatively lower growth pressure of the two-dimensional material layers helps increase atomic surface mobility, achieving planar growth. The two layers work together to effectively block the upward extension of dislocations and reduce leakage current.

[0076] In some embodiments, the growth pressure of the three-dimensional BAlN layer 61 is 300 torr to 600 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer 63 is 300 torr to 600 torr, the growth pressure of the two-dimensional AlN layer 62 is 50 torr to 300 torr, and the growth pressure of the two-dimensional superlattice layer 64 is 50 torr to 300 torr.

[0077] For example, the growth pressure of the three-dimensional BAlN layer 61 is 300 torr, 320 torr, 350 torr, 380 torr, 400 torr, 420 torr, 450 torr, 480 torr, 500 torr, 520 torr, 550 torr, 580 torr or 600 torr, but is not limited to this.

[0078] For example, the growth pressure of the three-dimensional Mg, H co-doped AlInGaN layer 63 is 300 torr, 320 torr, 350 torr, 380 torr, 400 torr, 420 torr, 450 torr, 480 torr, 500 torr, 520 torr, 550 torr, 580 torr or 600 torr, but is not limited to this.

[0079] For example, the growth pressure of the two-dimensional AlN layer 62 is 50 torr, 80 torr, 100 torr, 120 torr, 150 torr, 180 torr, 200 torr, 220 torr, 250 torr, 280 torr or 300 torr, but is not limited to this.

[0080] For example, the growth pressure of the two-dimensional superlattice layer 64 is 50 torr, 80 torr, 100 torr, 120 torr, 150 torr, 180 torr, 200 torr, 220 torr, 250 torr, 280 torr or 300 torr, but is not limited thereto.

[0081] In some embodiments, preferably, the thicknesses of the three-dimensional BAlN layer 61, the two-dimensional AlN layer 62, the three-dimensional Mg, H co-doped AlInGaN layer 63, and the two-dimensional superlattice layer 64 increase sequentially.

[0082] This incremental thickness design along the epitaxial direction introduces a relatively thin three-dimensional BAlN layer 61 in the early stage to form a high-density dislocation blocking interface, avoiding the introduction of additional stress due to excessive thickness. A two-dimensional AlN layer 62, which is slightly thicker than the three-dimensional BAlN layer 61, is then used to further annihilate dislocations and provide a better growth platform for subsequent three-dimensional material layers. The incremental thickness of the subsequent three-dimensional Mg and H co-doped AlInGaN layer 63 and two-dimensional superlattice layer 64 not only ensures the dislocation shielding effect but also effectively alleviates interlayer stress accumulation, reduces interface defect density, and gradually optimizes the hole transport path, improving the uniformity and stability of hole injection.

[0083] In some embodiments, the thickness of the three-dimensional BAlN layer 61 is 1 nm to 10 nm, the thickness of the two-dimensional AlN layer 62 is 1 nm to 10 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer 63 is 1 nm to 100 nm, and the thickness of the two-dimensional superlattice layer 64 is 1 nm to 200 nm.

[0084] The thickness of the three-dimensional BAlN layer 61 and the two-dimensional AlN layer 62 should not be too large. If the thickness of the three-dimensional BAlN layer 61 and the two-dimensional AlN layer 62 is too large in the early stage, it is easy to induce stress relaxation and defect proliferation, resulting in lattice defects or even voids at the interface between the dislocation shielding layer 6 and the V-shaped pit, which will destroy the compactness and continuity of the interface, thereby weakening its dislocation shielding ability and affecting the growth quality and hole injection effect of subsequent material layers.

[0085] The thickness of the two-dimensional superlattice layer 64 should not be too small, otherwise it will be difficult to form a smooth surface on the surface of the active layer 5 with V-shaped pits, which will affect the growth quality of subsequent epitaxial materials and the hole injection effect.

[0086] For example, the thickness of the three-dimensional BAlN layer 61 can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, but is not limited thereto.

[0087] For example, the thickness of the two-dimensional AlN layer 62 can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, but is not limited thereto.

[0088] For example, the thickness of the three-dimensional Mg, H co-doped AlInGaN layer 63 can be 1 nm, 5 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 30 nm, 32 nm, 35 nm, 38 nm, 40 nm, 42 nm, 45 nm, 48 nm, 50 nm, 52 nm, 55 nm, 58 nm, 60 nm, 62 nm, 65 nm, 68 nm, 70 nm, 72 nm, 75 nm, 78 nm, 80 nm, 82 nm, 85 nm, 88 nm, 90 nm, 92 nm, 95 nm, 98 nm or 100 nm, but is not limited thereto.

[0089] For example, the thickness of the two-dimensional superlattice layer 64 may be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm or 200 nm, but is not limited thereto.

[0090] In some embodiments, in the three-dimensional Mg and H co-doped AlInGaN layer 63, the Al component content is 0.01~0.1 and the In component content is 0.01~0.1.

[0091] In some embodiments, the In content in the two-dimensional Mg and H co-doped InGaN layer 642 is 0.01~0.1%.

[0092] In some embodiments, the Al component content in the two-dimensional AlGaN layer 641 is 0.01~0.1%.

[0093] In some embodiments, in the same period of the two-dimensional superlattice layer 64, the thickness ratio of the two-dimensional AlGaN layer 641 to the two-dimensional Mg, H co-doped InGaN layer 642 is 1:1 to 10.

[0094] For example, in the same period of the two-dimensional superlattice layer 64, the thickness ratio of the two-dimensional AlGaN layer 641 to the two-dimensional Mg,H co-doped InGaN layer 642 is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited thereto.

[0095] Preferably, in the same period of the two-dimensional superlattice layer 64, the thickness of the two-dimensional AlGaN layer 641 is less than the thickness of the two-dimensional Mg and H co-doped InGaN layer 642. The thicker two-dimensional Mg and H co-doped InGaN layer 642 can provide more sufficient transport channels for holes, effectively improving the uniformity of holes.

[0096] Preferably, in the same period of the two-dimensional superlattice layer 64, the thickness ratio of the two-dimensional AlGaN layer 641 to the two-dimensional Mg,H co-doped InGaN layer 642 is 1:2 to 10. More preferably, in the same period of the two-dimensional superlattice layer 64, the thickness ratio of the two-dimensional AlGaN layer 641 to the two-dimensional Mg,H co-doped InGaN layer 642 is 1:2 to 3. Within this range, it is beneficial for efficient hole transport and can effectively alleviate stress accumulation.

[0097] Secondly, the present invention also provides a method for fabricating a light-emitting diode epitaxial structure, comprising:

[0098] S100. Provide substrate 1;

[0099] S200. A buffer layer 2 and an undoped GaN layer 3 are sequentially grown on substrate 1;

[0100] S300. An N-type layer 4 with V-shaped pits is grown on an undoped GaN layer 3;

[0101] S400. An active layer 5 is grown on the N-type layer 4. The active layer 5 forms a V-shaped pit at the corresponding position of the V-shaped pit in the N-type layer 4. Here, "forms according to shape" means that it grows epitaxially according to the morphological contour of the surface of the N-type layer 4 so that the active layer 5 also sinks to form a V-shaped pit at the corresponding position of the V-shaped pit in the N-type layer 4.

[0102] S500. A dislocation shielding layer 6 is grown on the active layer 5, and the dislocation shielding layer 6 fills and merges the V-shaped pits on the active layer 5;

[0103] S600. An electron blocking layer 7 and a P-type layer 8 are sequentially grown on the dislocation shielding layer 6;

[0104] The dislocation shielding layer 6 includes a three-dimensional BAlN layer 61, a two-dimensional AlN layer 62, a three-dimensional Mg and H co-doped AlInGaN layer 63 and a two-dimensional superlattice layer 64 that are grown sequentially along the epitaxial direction. The two-dimensional superlattice layer 64 includes a two-dimensional AlGaN layer 641 and a two-dimensional Mg and H co-doped InGaN layer 642 that are grown periodically and alternately.

[0105] The content of B component in the three-dimensional BAlN layer 61 decreases along the epitaxial direction;

[0106] In the two-dimensional superlattice layer 64, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer 642 in each period increases layer by layer with the accumulation of the number of periods.

[0107] In some embodiments, the growth temperature of the undoped GaN layer 3 is 1050℃~1200℃, the growth pressure is 100 torr~600 torr, and the growth thickness is 1μm~5μm. Using a higher growth temperature for the undoped GaN layer 3 can improve crystal quality. As its growth thickness increases, compressive stress is released through stacking faults, thereby reducing line defects, improving crystal quality, and reducing reverse leakage current. However, increasing the GaN layer thickness consumes a large amount of Ga source material, significantly increasing material costs. Therefore, preferably, the growth thickness is 2μm~3μm. Within this range, high crystal quality can be ensured while saving production costs.

[0108] In some embodiments, the N-type layer 4 can be an N-type GaN layer, with a growth temperature of 1050℃~1200℃, a growth thickness of 2μm~3μm, a growth pressure of 100torr~600torr, and a Si doping concentration of 1×10⁻⁶. 19 cm -3 ~5×10 19 cm -3 .

[0109] In some embodiments, the active layer 5 is an InGaN quantum well layer and an AlGaN quantum barrier layer grown in alternating cycles, with 6 to 12 cycles. The growth temperature of the InGaN quantum well layer is 790°C to 810°C, the thickness of a single layer is 2 nm to 5 nm, and the growth pressure is 50 torr to 300 torr. The growth temperature of the AlGaN quantum barrier layer is 800°C to 900°C, the thickness of a single layer is 5 nm to 15 nm, the growth pressure is 50 torr to 300 torr, and the Al content is 0.01 to 0.1%.

[0110] In some embodiments, the electron blocking layer 7 may be AlInGaN, grown at a temperature of 900℃~1000℃, a growth pressure of 100 torr~300 torr, and a growth thickness of 10 nm~40 nm, wherein the Al content is 0.005~0.1% and the In content is 0.01~0.2%. Preferably, the Al content in AlInGaN increases along the epitaxial direction, and the In content decreases along the epitaxial direction.

[0111] In some embodiments, the p-type layer 8 may be a p-type GaN layer with a growth thickness of 10 nm to 50 nm, a growth pressure of 100 torr to 600 torr, and a Mg doping concentration of 1 × 10⁻⁶. 19 cm -3 ~1×10 21 cm -3 Excessive Mg doping concentration can damage crystal quality, while low doping concentration can affect hole concentration. Preferably, the P-type GaN layer is a high-temperature P-type layer 8, with a growth temperature of 900℃~1050℃. Using a higher growth temperature for the P-type GaN layer helps to reduce leakage current channels and effectively limit electron overflow.

[0112] Furthermore, the present invention also provides a light-emitting diode, comprising the above-described light-emitting diode epitaxial structure; or,

[0113] The above-mentioned method for fabricating an epitaxial structure of a light-emitting diode includes an epitaxial structure of a light-emitting diode.

[0114] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0115] Example 1

[0116] This embodiment discloses a light-emitting diode epitaxial structure, including a substrate and an epitaxial layer. The epitaxial layer includes a buffer layer, an undoped GaN layer, an N-type layer, an active layer, an electron blocking layer and a P-type layer grown sequentially along the epitaxial direction. A V-shaped pit is formed from the N-type layer to the active layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer, and the dislocation shielding layer fills and merges the V-shaped pit on the active layer.

[0117] The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a periodically alternating two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer.

[0118] The content of the B component in the three-dimensional BAlN layer decreases from 0.2 to 0.05 along the epitaxial direction;

[0119] In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the cumulative number of periods, with a single increase of 15% and 10 periods.

[0120] In this embodiment, the Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer is greater than the Mg doping concentration in the three-dimensional Mg and H co-doped AlInGaN layer.

[0121] In this embodiment, the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer is 6.7 × 10⁻⁶. 19 cm -3 The H doping concentration is 3.5 × 10⁻⁶. 16 cm -3 In the first period of the two-dimensional superlattice layer, the Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is 2.1 × 10⁻⁶. 20 cm -3 The H doping concentration is 2.6 × 10⁻⁶. 17 cm -3 .

[0122] In this embodiment, the growth pressure of the three-dimensional BAlN layer and the three-dimensional Mg and H co-doped AlInGaN layer are both greater than the growth pressure of the two-dimensional AlN layer and the two-dimensional superlattice layer.

[0123] In this embodiment, the growth pressure of the three-dimensional BAlN layer is 500 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer is 500 torr, the growth pressure of the two-dimensional AlN layer is 200 torr, and the growth pressure of the two-dimensional superlattice layer is 200 torr.

[0124] In this embodiment, preferably, the thicknesses of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg, H co-doped AlInGaN layer, and the two-dimensional superlattice layer increase sequentially.

[0125] In this embodiment, the thickness of the three-dimensional BAlN layer is 3.7 nm, the thickness of the two-dimensional AlN layer is 5.3 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 25 nm, and the thickness of the two-dimensional superlattice layer is 60 nm.

[0126] In this embodiment, the Al component content in the three-dimensional Mg and H co-doped AlInGaN layer is 0.07 and the In component content is 0.05.

[0127] In this embodiment, the In content in the two-dimensional Mg and H co-doped InGaN layer is 0.05%.

[0128] In this embodiment, the Al component content in the two-dimensional AlGaN layer is 0.06%.

[0129] In this embodiment, the thickness ratio of the two-dimensional AlGaN layer to the two-dimensional Mg, H co-doped InGaN layer in the same period of the two-dimensional superlattice layer is 1:2.

[0130] Example 2

[0131] This embodiment discloses a light-emitting diode epitaxial structure, including a substrate and an epitaxial layer. The epitaxial layer includes a buffer layer, an undoped GaN layer, an N-type layer, an active layer, an electron blocking layer and a P-type layer grown sequentially along the epitaxial direction. A V-shaped pit is formed from the N-type layer to the active layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer, and the dislocation shielding layer fills and merges the V-shaped pit on the active layer.

[0132] The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a periodically alternating two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer.

[0133] The content of the B component in the three-dimensional BAlN layer decreases from 0.2 to 0.05 along the epitaxial direction;

[0134] In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the cumulative number of periods, with a single increase of 10% and 10 periods.

[0135] In this embodiment, the Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer is greater than the Mg doping concentration in the three-dimensional Mg and H co-doped AlInGaN layer.

[0136] In this embodiment, the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer is 2.5 × 10⁻⁶. 19 cm -3 The H doping concentration is 2.7 × 10⁻⁶. 16 cm -3 In the first period of the two-dimensional superlattice layer, the Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer is 1.5 × 10⁻⁶. 20 cm -3 The H doping concentration is 1.9 × 10⁻⁶. 17 cm -3 .

[0137] In this embodiment, the growth pressure of the three-dimensional BAlN layer and the three-dimensional Mg and H co-doped AlInGaN layer are both greater than the growth pressure of the two-dimensional AlN layer and the two-dimensional superlattice layer.

[0138] In this embodiment, the growth pressure of the three-dimensional BAlN layer is 500 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer is 500 torr, the growth pressure of the two-dimensional AlN layer is 200 torr, and the growth pressure of the two-dimensional superlattice layer is 200 torr.

[0139] In this embodiment, preferably, the thicknesses of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg, H co-doped AlInGaN layer, and the two-dimensional superlattice layer increase sequentially.

[0140] In this embodiment, the thickness of the three-dimensional BAlN layer is 3.7 nm, the thickness of the two-dimensional AlN layer is 5.3 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 25 nm, and the thickness of the two-dimensional superlattice layer is 60 nm.

[0141] In this embodiment, the Al component content in the three-dimensional Mg and H co-doped AlInGaN layer is 0.07 and the In component content is 0.05.

[0142] In this embodiment, the In content in the two-dimensional Mg and H co-doped InGaN layer is 0.05%.

[0143] In this embodiment, the Al component content in the two-dimensional AlGaN layer is 0.06%.

[0144] In this embodiment, the thickness ratio of the two-dimensional AlGaN layer to the two-dimensional Mg, H co-doped InGaN layer in the same period of the two-dimensional superlattice layer is 1:2.

[0145] Example 3

[0146] This embodiment discloses a light-emitting diode epitaxial structure, including a substrate and an epitaxial layer. The epitaxial layer includes a buffer layer, an undoped GaN layer, an N-type layer, an active layer, an electron blocking layer and a P-type layer grown sequentially along the epitaxial direction. A V-shaped pit is formed from the N-type layer to the active layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer, and the dislocation shielding layer fills and merges the V-shaped pit on the active layer.

[0147] The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a periodically alternating two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer.

[0148] The content of the B component in the three-dimensional BAlN layer decreases from 0.45 to 0.2 along the epitaxial direction;

[0149] In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the cumulative number of periods, with a single increase of 15% and 10 periods.

[0150] In this embodiment, the Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer is greater than the Mg doping concentration in the three-dimensional Mg and H co-doped AlInGaN layer.

[0151] In this embodiment, the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer is 6.7 × 10⁻⁶. 19 cm -3 The H doping concentration is 3.5 × 10⁻⁶. 16 cm -3 In the first period of the two-dimensional superlattice layer, the Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is 2.1 × 10⁻⁶. 20 cm -3 The H doping concentration is 2.6 × 10⁻⁶. 17 cm -3 .

[0152] In this embodiment, the growth pressure of the three-dimensional BAlN layer and the three-dimensional Mg and H co-doped AlInGaN layer are both greater than the growth pressure of the two-dimensional AlN layer and the two-dimensional superlattice layer.

[0153] In this embodiment, the growth pressure of the three-dimensional BAlN layer is 500 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer is 500 torr, the growth pressure of the two-dimensional AlN layer is 200 torr, and the growth pressure of the two-dimensional superlattice layer is 200 torr.

[0154] In this embodiment, preferably, the thicknesses of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg, H co-doped AlInGaN layer, and the two-dimensional superlattice layer increase sequentially.

[0155] In this embodiment, the thickness of the three-dimensional BAlN layer is 3.7 nm, the thickness of the two-dimensional AlN layer is 5.3 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 25 nm, and the thickness of the two-dimensional superlattice layer is 60 nm.

[0156] In this embodiment, the Al component content in the three-dimensional Mg and H co-doped AlInGaN layer is 0.07 and the In component content is 0.05.

[0157] In this embodiment, the In content in the two-dimensional Mg and H co-doped InGaN layer is 0.05%.

[0158] In this embodiment, the Al component content in the two-dimensional AlGaN layer is 0.06%.

[0159] In this embodiment, the thickness ratio of the two-dimensional AlGaN layer to the two-dimensional Mg, H co-doped InGaN layer in the same period of the two-dimensional superlattice layer is 1:2.

[0160] Comparative Example 1

[0161] The difference between this comparative example and Example 1 is that, in this comparative example, the three-dimensional Mg, H co-doped AlInGaN layer is replaced with a three-dimensional Mg-doped AlInGaN layer. That is, during deposition, H is not intentionally doped, and the Mg doping concentration is 6.7 × 10⁻⁶. 19 cm -3 .

[0162] The two-dimensional Mg, H co-doped InGaN layer was replaced with a two-dimensional Mg-doped InGaN layer; that is, H was not intentionally doped during deposition. The Mg doping concentration in the two-dimensional Mg-doped InGaN layer in each period of the two-dimensional superlattice layer was 6.7 × 10⁻⁶. 19 cm -3 .

[0163] Comparative Example 2

[0164] The difference between this comparative example and Example 1 is that in this comparative example, the thickness of the three-dimensional BAlN layer is 25 nm, the thickness of the two-dimensional AlN layer is 30 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 3.7 nm, and the thickness of the two-dimensional superlattice layer is 35.3 nm. Furthermore, the B component content in the three-dimensional BAlN layer is maintained at 0.2%.

[0165] Comparative Example 3

[0166] The difference between this comparative example and Example 1 is that in this comparative example, the dislocation shielding layer does not have a three-dimensional BAlN layer and a two-dimensional AlN layer, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 25 nm, and the thickness of the two-dimensional superlattice layer is 69.1 nm.

[0167] Comparative Example 4

[0168] The difference between this comparative example and Example 1 is that in this comparative example, the dislocation shielding layer does not have a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer, the thickness of the three-dimensional BAlN layer is 3.7 nm, and the thickness of the two-dimensional AlN layer is 90.3 nm.

[0169] Comparative Example 5

[0170] The difference between this comparative example and Example 1 is that the dislocation shielding layer is replaced with a GaN layer with a thickness of 94 nm.

[0171] The brightness of the samples prepared by Examples 1 to 3 and Comparative Examples 1 to 5 was tested. The brightness L1 measured by Examples 1 to 3 and Comparative Examples 1 to 4 was compared with the brightness L2 measured by Comparative Example 5 to obtain the corresponding luminous efficacy improvement rate.

[0172] The formula for calculating the luminous efficacy improvement rate W is: W=(L1-L2) / L2.

[0173] The results are as follows:

[0174]

[0175] Comparing Example 1, Example 2 and Comparative Example 1, it can be seen that the dislocation shielding layer of the present invention adopts a three-dimensional Mg and H co-doped AlInGaN and a two-dimensional Mg and H co-doped InGaN layer, and controls the Mg doping concentration in the three-dimensional Mg and H co-doped AlInGaN to be lower than that in the two-dimensional Mg and H co-doped InGaN layer. The Mg doping concentration in the two-dimensional Mg and H co-doped InGaN layer increases layer by layer with the accumulation of the number of periods, which can effectively improve the luminous efficiency.

[0176] Comparing Example 1, Example 3 and Comparative Example 2, it can be seen that by controlling the content of the B component in the three-dimensional BAlN layer to decrease along the epitaxial direction and by increasing the thickness of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg, H co-doped AlInGaN layer and the two-dimensional superlattice layer in sequence, the luminescence efficiency can be effectively improved.

[0177] Comparing Example 1 with Comparative Examples 3 to 5, it can be seen that the sub-layers of the dislocation shielding layer in this invention cooperate with each other to effectively improve luminous efficiency.

[0178] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A light-emitting diode epitaxial structure, comprising a substrate and an epitaxial layer, characterized in that, The epitaxial layer includes a buffer layer, an undoped GaN layer, an N-type layer, an active layer, an electron blocking layer, and a P-type layer that are grown sequentially along the epitaxial direction. A V-shaped pit is formed from the N-type layer to the active layer. A dislocation shielding layer is provided between the active layer and the electron blocking layer, and the dislocation shielding layer fills and merges the V-shaped pit on the active layer. The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a periodically alternating two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer. The content of the B component in the three-dimensional BAlN layer decreases along the epitaxial direction. In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the accumulation of the number of periods.

2. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, The content of B component in the three-dimensional BAlN layer is 0.01~0.5%.

3. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, The Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is greater than the Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer; and / or, The Mg doping concentration in the three-dimensional Mg, H co-doped AlInGaN layer is 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 The Mg doping concentration in the two-dimensional Mg, H co-doped InGaN layer is 1×10⁻⁶. 20 cm -3 ~1×10 21 cm -3 The H doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3 .

4. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg, H co-doped InGaN layer in the i-th period is N. i The Mg doping concentration of the two-dimensional Mg, H co-doped InGaN layer in the (i+1)th period is N. i+1 , where i is a positive integer, and 101%N i ≤N i+1 ≤150%N i .

5. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, The growth atmosphere for both the three-dimensional BaAlN layer and the two-dimensional AlN layer is N2 and NH3, and the flow rate ratio of N2 to NH3 is 1:1~10. The growth atmosphere of the three-dimensional Mg and H co-doped AlInGaN layer and the two-dimensional Mg and H co-doped InGaN layer is N2, H2 and NH3, and the flow rate ratio of N2, H2 and NH3 is 1:1~10:1~10.

6. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, The growth pressure of the three-dimensional BAlN layer and the growth pressure of the three-dimensional Mg,H co-doped AlInGaN layer are both greater than the growth pressure of the two-dimensional AlN layer and the growth pressure of the two-dimensional superlattice layer; and / or, The growth pressure of the three-dimensional BAlN layer is 300 torr to 600 torr, the growth pressure of the three-dimensional Mg and H co-doped AlInGaN layer is 300 torr to 600 torr, the growth pressure of the two-dimensional AlN layer is 50 torr to 300 torr, and the growth pressure of the two-dimensional superlattice layer is 50 torr to 300 torr.

7. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, The thicknesses of the three-dimensional BAlN layer, the two-dimensional AlN layer, the three-dimensional Mg,H co-doped AlInGaN layer, and the two-dimensional superlattice layer increase sequentially; and / or, The thickness of the three-dimensional BAlN layer is 1 nm to 10 nm, the thickness of the two-dimensional AlN layer is 1 nm to 10 nm, the thickness of the three-dimensional Mg and H co-doped AlInGaN layer is 1 nm to 100 nm, and the thickness of the two-dimensional superlattice layer is 1 nm to 200 nm.

8. The epitaxial structure of a light-emitting diode according to claim 1, characterized in that, In the same period of the two-dimensional superlattice layer, the thickness ratio of the two-dimensional AlGaN layer to the two-dimensional Mg,H co-doped InGaN layer is 1:1~10; or, In the same period of the two-dimensional superlattice layer, the thickness of the two-dimensional AlGaN layer is less than the thickness of the two-dimensional Mg, H co-doped InGaN layer.

9. A method for fabricating an epitaxial structure of a light-emitting diode, characterized in that, include: Provide substrate; A buffer layer and an undoped GaN layer are sequentially grown on the substrate; An N-type layer with V-shaped pits is grown on the undoped GaN layer; An active layer is grown on the N-type layer, and the active layer forms a V-shaped pit at the corresponding position of the V-shaped pit in the N-type layer. A dislocation shielding layer is grown on the active layer, and the dislocation shielding layer fills and merges the V-shaped pits on the active layer; An electron blocking layer and a P-type layer are sequentially grown on the dislocation shielding layer; The dislocation shielding layer includes a three-dimensional BAlN layer, a two-dimensional AlN layer, a three-dimensional Mg and H co-doped AlInGaN layer and a two-dimensional superlattice layer grown sequentially along the epitaxial direction. The two-dimensional superlattice layer includes a two-dimensional AlGaN layer and a two-dimensional Mg and H co-doped InGaN layer grown periodically and alternately. The content of the B component in the three-dimensional BAlN layer decreases along the epitaxial direction. In the two-dimensional superlattice layer, the Mg doping concentration of the two-dimensional Mg and H co-doped InGaN layer in each period increases layer by layer with the accumulation of the number of periods.

10. A light-emitting diode, characterized in that, Includes a light-emitting diode epitaxial structure according to any one of claims 1 to 8; or, This includes the light-emitting diode epitaxial structure prepared by the method for preparing a light-emitting diode epitaxial structure according to claim 9.

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