Light emitting diode, preparation method thereof and communication system

Abstract

The invention relates to the technical field of semiconductors, and provides a light-emitting diode, a preparation method thereof and a communication system. The light emitting diode comprises a substrate, a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence. The active layer comprises at least one group of quantum well layers and quantum barrier layers which are periodically and alternately stacked; the quantum well layer comprises an In component; the active layer further comprises at least one covering layer; the covering layer is located between the quantum well layer and the quantum barrier layer; the material of the covering layer is selected from a III-V group nitride semiconductor material, and the bond energy of a chemical bond formed by a metal element contained in the III-V group nitride semiconductor material and a nitrogen element is higher than the bond energy of In-N formed by an indium element and the nitrogen element in the quantum well layer. Through the above arrangement, mutual diffusion of In atoms in the quantum well containing the In component is effectively inhibited, a clear interface of the quantum well layer is maintained, and high-speed LED communication is further realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a light-emitting diode, its fabrication method, and a communication system. Background Technology

[0002] Light-emitting diodes (LEDs), as efficient and stable solid-state light sources, have been widely used in lighting, displays, and other fields. In recent years, with the development of technologies such as visible light communication, higher requirements have been placed on the photoelectric performance of LEDs.

[0003] In LEDs, the emission wavelength is achieved by adjusting the indium (In) composition in the active layer quantum well. Generally, increasing the In composition yields a longer emission wavelength. However, a higher In composition leads to significant lattice mismatch between the quantum well and adjacent layers, causing disordered atomic arrangement at the interface, increasing interface roughness, and forming numerous crystal defects. Furthermore, In atoms have low binding energy in the nitride lattice, making them prone to diffuse outward from the quantum well during subsequent high-temperature epitaxial processes, thus degrading the LED's luminous efficiency, wavelength stability, and other performance characteristics. Summary of the Invention

[0004] To address the technical problems of easy outward diffusion of In atoms and high interface roughness in In-containing quantum well layers in the prior art, the present invention provides a light-emitting diode, comprising a substrate and a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the substrate; the active layer comprises at least one set of periodically alternating quantum well layers and quantum barrier layers; the quantum well layer contains an In component; the active layer further comprises at least one capping layer; the capping layer is located between the quantum well layer and the quantum barrier layer; the material of the capping layer is selected from group III-V nitride semiconductor materials, wherein the bond energy of the chemical bond formed between the metal element and nitrogen element in the group III-V nitride semiconductor material is higher than the In-N bond energy formed between indium element and nitrogen element in the quantum well layer.

[0005] In one embodiment, the material of the capping layer is selected from one or more of GaN, AlGaN, and AlInGaN.

[0006] In one embodiment, the thickness of the capping layer is less than the thickness of the quantum well layer, or the thickness of the capping layer is less than the thickness of the quantum barrier layer, or the thickness of the capping layer is less than both the thickness of the quantum well layer and the thickness of the quantum barrier layer.

[0007] In one embodiment, the In content in the quantum well layer is between 0.10 and 0.45, and the emission wavelength of the light-emitting diode is between 500 nm and 750 nm.

[0008] In one embodiment, when the material of the covering layer is selected from Al x Ga （1-x） When N is constant, 0.03 < x < 0.7; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.03 < y < 0.7.

[0009] In one embodiment, when the material of the covering layer is selected from Al x Ga （1-x） When N is constant, 0.1 < x < 0.3; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.1 < y < 0.3.

[0010] In one embodiment, the thickness of the covering layer is between 0.5 nm and 3 nm.

[0011] In one embodiment, during the growth of the active layer, an interface interruption process is performed at the quantum well layer interface, the capping layer interface, or the interface between the two; the interface interruption process involves stopping the supply of the metal-organic source and introducing a processing gas; the processing gas is selected from any one or a mixture of nitrogen, hydrogen, and ammonia.

[0012] In one embodiment, the root mean square roughness of the interface of the quantum well layer is less than 3 nm.

[0013] In one embodiment, the root mean square roughness of the interface of the quantum well layer is less than 0.5 nm.

[0014] In one embodiment, the light-emitting diode has a modulation bandwidth greater than 100MHz under the −3dB standard.

[0015] In one embodiment, the light-emitting diode has a modulation bandwidth greater than 1 GHz under the −3dB standard.

[0016] In one embodiment, the second semiconductor layer includes an electron blocking layer and a p-type nitride layer, wherein the electron blocking layer is located above the active layer and is made of a wide bandgap material; the p-type nitride layer may be selected from GaN or InGaN.

[0017] In one embodiment, the light-emitting diode further includes a transparent electrode and an n-type electrode. The transparent electrode is located on the light-emitting side of the light-emitting diode and is electrically connected to the second semiconductor layer. The n-type electrode is located on the non-light-emitting side of the light-emitting diode and is electrically connected to the first semiconductor layer.

[0018] This invention also provides a method for fabricating a light-emitting diode, comprising the following steps: Provide substrate; A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially grown on the substrate; wherein, the active layer includes at least one set of periodically alternating quantum well layers and quantum barrier layers; the quantum well layers contain an In composition; the active layer further includes at least one capping layer, the capping layer being located between the quantum well layers and the quantum barrier layers; During the growth of the active layer, at least one interface interruption process is performed, which includes stopping the supply of the metal-organic source and introducing a processing gas, wherein the processing gas is selected from any one or a mixture of nitrogen, hydrogen, and ammonia. The timing for executing the interface interruption handling is selected from at least one of the following: After the quantum well layer has been grown, but before the corresponding capping layer has been grown; After at least one of the capping layers has been grown, but before the corresponding quantum barrier layer has been grown; After the quantum well layer is grown and the interface interruption process is executed, another capping layer is grown, but before the corresponding quantum barrier layer is grown.

[0019] In one embodiment, the processing time of the interface interruption process is between 1s and 80s, the temperature of the interface interruption process is between 500℃ and 1000℃, and the flow rate of the processing gas is between 500 sccm and 100000 sccm; or the processing time of the interface interruption process is between 2s and 30s, the temperature of the interface interruption process is between 700℃ and 900℃, and the flow rate of the processing gas is between 500 sccm and 5000 sccm.

[0020] In one embodiment, the material of the capping layer is selected from group III-V nitride semiconductor materials, wherein the bond energy of the chemical bond formed between the metal element and the nitrogen element in the group III-V nitride semiconductor material is higher than the In-N bond energy formed between the indium element and the nitrogen element in the quantum well layer.

[0021] This invention also provides a communication system that uses a light-emitting diode as described in any of the above embodiments, wherein the data transmission rate of the communication system is greater than 1Gbps.

[0022] Based on the above, compared with the prior art, the light-emitting diode, its preparation method and communication system provided by the present invention have at least the following technical effects: 1. By setting a capping layer between the quantum well layer and the quantum barrier layer within at least one set of cycles of the active layer, the interdiffusion of In atoms in the In-containing quantum well is effectively suppressed, the clear interface of the quantum well layer is maintained, and thus the accuracy and consistency of the emission wavelength are ensured, enabling high-speed LED communication.

[0023] 2. By employing an interface interruption process, and through precise control of the interruption time, temperature, and processing gas, atomic-level reconstruction of the quantum well interface was achieved, significantly improving the interface quality.

[0024] 3. The interface interruption handling and the overlay layer work together to build a functional closed loop of "repair-blockage-stabilization", which significantly improves the overall performance of the device.

[0025] 4. Optimized interface characteristics effectively reduce carrier scattering and barrier fluctuations, improve carrier transport efficiency and recombination efficiency, and enable light-emitting diodes to meet the requirements of high-speed optical communication systems.

[0026] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other beneficial effects of the invention can be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0028] Figure 1 This is a cross-sectional view of a light-emitting diode provided in Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of another light-emitting diode provided in Embodiment 1 of the present invention; Figure 3 This is a bandwidth-current density characteristic curve of a light-emitting diode provided in Embodiment 2 of the present invention.

[0029] Figure label: 10. Substrate; 20. First semiconductor layer; 21. GaN template layer; 22. InGaN buffer layer; 30. Active layer; 31. Quantum well layer; 32. Capping layer; 33. Quantum barrier layer; 40. Second semiconductor layer; 41. Electron blocking layer; 42. p-type nitride layer. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0032] Example 1 Please see Figure 1 This invention provides a light-emitting diode, which includes a substrate 10, a first semiconductor layer 20, an active layer 30 and a second semiconductor layer 40 stacked sequentially.

[0033] The substrate 10 can be a conductive substrate or a non-conductive substrate, or a transparent substrate or a non-transparent substrate. For example, the substrate 10 can be sapphire (Al2O3), silicon carbide (SiC), silicon (Si), magnesium oxide (MgO), aluminum gallium oxide (LiGaO2), or gallium nitride (GaN), and this embodiment is not limited thereto. In some embodiments, the substrate 10 can be thinned or removed in subsequent processes.

[0034] The first semiconductor layer 20 can be selected as an N-type semiconductor layer or a P-type semiconductor layer according to the device structure requirements (such as upright, flip-chip or vertical structure). In this embodiment, the first semiconductor layer 20 preferably includes a GaN template layer 21 and an InGaN buffer layer 22. The InGaN buffer layer 22 acts as a strain transition layer to solve the significant lattice constant mismatch problem between the high indium composition quantum well 31 and the lower GaN template layer 21.

[0035] Accordingly, the second semiconductor layer 40 can be an N-type semiconductor layer or a P-type semiconductor layer, and its electrical properties differ from those of the first semiconductor layer 20. In this embodiment, the second semiconductor layer 40 preferably includes an electron blocking layer 41 and a p-type nitride layer 42. The p-type nitride layer 42 can be selected from GaN or InGaN materials. The electron blocking layer 41 is located above the entire active layer 30 and uses a wide bandgap material (such as p-type AlGaN). By forming a high barrier, it blocks electrons from escaping from the active region 30 and confines them within the well to recombine with holes.

[0036] It should be understood that both the first semiconductor layer 20 and the second semiconductor layer 40 can be single-layer structures or multi-layer structures with different compositions. It should also be noted that other functional structural layers that optimize the performance of the light-emitting element, such as ohmic contact layers and current-blocking layers, can be selected on the substrate according to actual needs.

[0037] Further, the active layer 30 includes at least one set of periodically alternating quantum well layers 31 and quantum barrier layers 33. To improve the luminous efficiency of the active layer 30, this can be achieved by changing the depth of the quantum well layers 31, the number of paired quantum well layers 31 and quantum barrier layers 32, their thickness, and / or other characteristics. The quantum well layers 31 contain an indium (In) component, specifically InGaN material, and the emission wavelength can be set by adjusting the In component. Preferably, the In component in the quantum well layers 31 is between 0.10 and 0.45, where a higher In component enables longer emission wavelengths while keeping lattice mismatch within an acceptable range. More preferably, the emission wavelength of the light-emitting diode is set in the range of 500 nm to 750 nm, meaning the visible light emitted by the active layer can be blue-green, green, yellow, orange, or red. Meanwhile, the quantum barrier layer 33 uses GaN or AlGaN material to confine charge carriers.

[0038] In one embodiment, the light-emitting diode further includes a transparent electrode (not shown), an n-type electrode (not shown), and a heat dissipation substrate. The transparent electrode is located on the light-emitting side of the light-emitting diode and is electrically connected to the second semiconductor layer, while the n-type electrode is located on the non-light-emitting side of the light-emitting diode and is electrically connected to the first semiconductor layer. These electrodes respectively perform current spreading, ohmic contact, and thermal management functions, jointly ensuring the device's electrical injection efficiency and thermal stability.

[0039] In a preferred embodiment, the heat dissipation substrate is used for device thermal management to ensure thermal stability under high current density operation. Specific implementation methods include, but are not limited to: directly using the substrate as a heat dissipation substrate, where the substrate is selected from materials with excellent thermal conductivity, such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN) substrates. Alternatively, after epitaxial structure growth is completed, the light-emitting diode structure is transferred and bonded to a dedicated thermally conductive substrate, such as an aluminum nitride (AlN) ceramic substrate, a copper-clad ceramic substrate (such as a directly copper-clad AlN or directly copper-clad Si3N4 substrate), or a high thermal conductivity metal substrate, through substrate peeling and bonding processes.

[0040] However, a high In content leads to significant lattice mismatch between the quantum well layer 31 and adjacent layers, resulting in disordered atomic arrangement at the interface, increased interface roughness, and the formation of a large number of crystal defects. Moreover, the binding energy of In atoms in the nitride lattice is low, making them prone to diffusion from the quantum well to the outside during subsequent high-temperature epitaxial processes, which in turn degrades the luminous efficiency, wavelength stability, and other properties of the LED.

[0041] To address the aforementioned issues, this embodiment introduces and optimizes the design of a capping layer 32 to effectively block the outward diffusion of In atoms, thereby maintaining the compositional uniformity of the quantum well layer 31 and preventing wavelength shifts caused by component migration. Simultaneously, interface interruption processing further reduces the interface roughness of the quantum well layer 31, optimizes carrier transport and recombination efficiency, and enhances the luminous performance and operational stability of the LED.

[0042] Please see Figure 1 and Figure 2Specifically, the active layer 30 also includes at least one capping layer 32, which is grown between the quantum well layer 31 and the quantum barrier layer 33. It should be noted that the capping layer 32 can be flexibly configured: it can be a single layer located between the topmost quantum well layer 31 and the quantum barrier layer 33 within the cycle; or it can be configured as multiple layers, each located between each quantum well layer 31 and the quantum barrier layer 33, to optimize the interface quality of each light-emitting unit. Furthermore, the capping layer 32 serves as a functional layer for suppressing indium diffusion in the quantum well layer 31, and its material is selected from group III-V nitride semiconductor materials, specifically one or more of GaN, AlGaN, and AlInGaN. These materials have good compatibility with the crystal structure of the quantum well layer 31, forming a tightly fitted interface with few defects. Moreover, the bond energy of the chemical bonds formed between the metal elements and nitrogen elements in these materials is higher than the In-N bond energy formed between indium and nitrogen elements in the quantum well layer 31, resulting in superior bonding strength. Therefore, it can both form a physical barrier through the tightly ordered atomic arrangement, blocking the migration path of In atoms, and rely on stronger chemical bonding forces to suppress the diffusion of In atoms outward from the quantum well due to thermal vibrations during subsequent high-temperature processes. More importantly, through the above settings, the periodic arrangement of interface atoms is stabilized, greatly reducing the fluctuations in carrier scattering centers and local barriers caused by missing or misaligned atoms at the interface. This improves the smoothness and stability of the interface, thereby affecting the modulation bandwidth of the light-emitting device.

[0043] It should be noted that when AlGaN or AlInGaN is used, the introduced Al atoms can further enhance the chemical bond energy and improve diffusion barrier capabilities, but precise control of composition parameters is needed to balance performance and compatibility. Specifically, when the coating material is selected from Al... x Ga （1-x） When N is constant, 0.03 < x < 0.7; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.03 < y < 0.7. More preferably, when the material of the covering layer is selected from Al... x Ga （1-x） When N is constant, 0.1 < x < 0.3; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.1 < y < 0.3. If the values ​​of x or y are too small, the bond energy increase brought by Al atoms is limited, making it difficult to effectively enhance the diffusion blocking effect; if the values ​​of x or y are too large, it will exacerbate the lattice mismatch with quantum well layer 31, leading to an increase in interface defects. By limiting the above-mentioned Al composition x and y, the In diffusion suppression effect can be maximized while ensuring interface quality, avoiding stress concentration or an increase in defects, and ensuring efficient carrier transport and recombination.

[0044] In a preferred embodiment, the thickness of the capping layer 32 is less than the thickness of the quantum well layer 31 or the quantum barrier layer 33; or the thickness of the capping layer 32 is less than the thickness of the quantum well layer 31 or the quantum barrier layer 33. As an example, the thickness of the capping layer 32 is between 0.5 and 3 nm. This relatively thin capping layer 32 design allows for rapid film formation, achieving immediate passivation and protection of highly active In atoms; it also avoids a degradation in the quality of the active layer 30 due to an excessively thick capping layer 32.

[0045] Furthermore, to address the lattice mismatch and interface instability caused by the high indium content in the active layer 30, this embodiment of the invention also achieves a significant improvement in interface characteristics by introducing an interface interruption process. This process, after interface growth is complete, involves pausing the supply of the metal-organic source and introducing a specific processing gas to provide kinetic conditions for the migration and rearrangement of atoms on the interface surface, thereby effectively repairing interface micro-defects. Specifically, the interface interruption process can be performed at the following three different times: 1. An interface interruption process is performed at the interface of the quantum well layer 31. That is, after the growth of each quantum well layer 31 is completed and before the growth of the capping layer 32 begins, the interface interruption process is performed. This method can directly repair the disordered atomic arrangement and dangling bonds caused by the growth of high In composition on the surface of the quantum well layer 31, so that a flat and ordered atomic structure is formed on the surface of the quantum well layer 31. This provides a high-quality substrate for the subsequent capping layer 32 and suppresses the initial diffusion tendency of In atoms at the interface from the source.

[0046] 2. An interface interruption process is performed at the interface of capping layer 32, that is, after at least one capping layer 32 has grown and before the growth of quantum barrier layer 33 begins. This process optimizes the surface morphology of capping layer 32, eliminates lattice distortion and interface stress that may remain during the growth of capping layer 32, and allows capping layer 32 to form a tightly fitted, gapless interface with the subsequent quantum barrier layer 33. This prevents interface gaps from providing channels for In atom diffusion and further enhances the diffusion blocking effect of the capping layer.

[0047] 3. Interface interruption processing is performed at both the quantum well layer 32 interface and the capping layer 33 interface. Specifically, interface interruption processing is performed once after each quantum well layer 31 has grown to repair surface defects in the quantum well layer 31; then, after at least one capping layer 32 has grown, interface interruption processing is performed again to optimize the surface of the capping layer 32. This progressive processing of the two key interfaces ensures both the interface matching degree between the quantum well layer 31 and the capping layer 32 and improves the connection quality between the capping layer 32 and the quantum barrier layer 33, blocking the diffusion of In atoms through a dual-pathway approach and enhancing the overall suppression effect.

[0048] After the aforementioned interface interruption process, the root mean square roughness of the quantum well layer 31 can be controlled within a range of less than 3 nm; preferably, the root mean square roughness is controlled within a range of less than 0.5 nm. Compared to the case without interface interruption, where the root mean square roughness of the quantum well layer 31 is generally only maintained between 0.5 nm and 1 nm due to the high In composition growth and lattice mismatch, this embodiment significantly achieves interface smoothing through this process. Furthermore, it greatly reduces interface scattering and barrier fluctuations, improving carrier transport.

[0049] This invention is applicable to a wide wavelength range of 500 nm to 750 nm, and is particularly effective for red Micro-LEDs with high In content. As wavelength increases, higher In content exacerbates lattice mismatch and In atom diffusion, leading to interface quality deterioration and reduced modulation bandwidth. This invention addresses the three core challenges of diffusion, defects, and lattice mismatch caused by high In content in red LEDs through the synergistic effect of the capping layer 32 and interface interruption treatment.

[0050] Specifically, on the one hand, the interface interruption treatment provides the foundation for the function of the capping layer 32: by optimizing the interface structure and repairing the surface defects of the quantum well layer 31, the "defect" problem is solved, and the capping layer 32 can be tightly attached to the quantum well layer 31, avoiding the formation of In atom diffusion channels and ensuring that the barrier function of the capping layer 32 is fully utilized. On the other hand, the capping layer 32 and the interface interruption treatment complement each other: the capping layer 32 grows on the optimized interface, which can effectively suppress the outward diffusion of In atoms and, to a certain extent, buffer the lattice mismatch between the quantum well layer 31 and the quantum barrier layer 33. In addition, the capping layer 32 also helps to solidify the smooth interface obtained by the interface interruption treatment, preventing secondary roughening of the interface or defect regeneration in subsequent high-temperature processes.

[0051] In summary, the interface interruption processing and the cover layer 32 together form a closed loop of "repair-blocking-stabilization". The former is responsible for interface repair and optimization, while the latter undertakes diffusion blocking and structural stabilization functions. The two work together to fundamentally improve the interface quality, wavelength stability and modulation bandwidth performance of high In composition red light devices.

[0052] Example 2 This invention also provides a method for fabricating a light-emitting diode using a metal-organic chemical vapor deposition (MOCVD) apparatus, specifically including the following steps: A substrate 10 is provided; a first semiconductor layer 20, an active layer 30, and a second semiconductor layer 40 are sequentially grown on the substrate 10; wherein, the step of growing the active layer 30 includes: growing at least one set of periodically alternating quantum well layers 31 and quantum barrier layers 33; the quantum well layers 31 contain an In composition, and a capping layer 32 is grown on at least one quantum well layer 31.

[0053] This invention employs a unique interface interruption processing technology to effectively optimize the device performance of light-emitting diodes. Specifically, this process involves performing an interface interruption process at least once during the growth of the active layer 30. The timing of this interface interruption processing is selected based on the specific needs of interface optimization, including at least one of the following scenarios: After the quantum well layer 31 is grown and before the corresponding capping layer 32 is grown; After at least one capping layer 32 has been grown, but before the corresponding quantum barrier layer 33 has been grown; After the quantum well layer 31 is grown and the interface interruption process is executed, a capping layer 32 is grown, and before the corresponding quantum barrier layer 33 is grown.

[0054] Specifically, the interface interruption process involves pausing the flow of all metal-organic sources (such as Ga and Al) into the reaction chamber while only maintaining the flow of the treatment gas for several tens of seconds to induce atomic rearrangement at the interface, repair the interface roughness, and make its crystal structure clearer.

[0055] The interface interruption process described above takes between 1 second and 80 seconds, with a processing temperature between 500°C and 1000°C, and a processing gas flow rate between 500 sccm and 100,000 sccm. Within a more preferred implementation range that better balances production efficiency and interface optimization, the process parameters for the interface interruption process can be further optimized as follows: processing time between 2 seconds and 30 seconds, processing temperature between 700°C and 900°C, and processing gas flow rate controlled between 500 sccm and 5000 sccm. The interface interruption process is preferably implemented immediately after the growth of each quantum well layer 31 or at least one capping layer 32 to ensure the smoothing of each well / barrier interface.

[0056] The processing gas can be selected from one or more of nitrogen, hydrogen, and ammonia. During the interface reconstruction process, different gas components play their respective important roles: ammonia decomposes at high temperatures to generate active nitrogen atoms, which fill nitrogen vacancies, promote the migration and rearrangement of In or Ga atoms, and inhibit nitrogen / indium desorption, thus achieving interface smoothing. In addition, other compounds that decompose at the growth temperature to generate active nitrogen atoms can also be used as alternative or supplementary nitrogen sources. Hydrogen effectively improves the interface morphology and reduces interface roughness through selective etching of weakly bonded atoms on the surface, particularly by moderately removing unstable indium-rich clusters; nitrogen mainly serves as a carrier gas to maintain the stability of the reaction chamber environment. The above processing gases can be used individually or in a certain proportion according to specific process requirements to achieve better interface reconstruction results.

[0057] In one specific embodiment, the active layer 30 includes 20 alternating quantum well layers 31 and quantum barrier layers 33. After the growth of each quantum well layer 31 is completed, the supply of TMGa and TMAl is paused, and only NH3 is continuously introduced at a flow rate of 2000 sccm for 5 seconds. After the interface interruption process is completed, a metal-organic source of one or more combinations of TMAl, TMGa, or TMIn is rapidly introduced to grow an AlGaN or AlInGaN capping layer 32.

[0058] Through the above-mentioned process, the device interface quality and carrier transport efficiency are significantly improved. For example... Figure 3 Test data shows that a 20μm diameter Micro-LED array achieved a modulation bandwidth greater than 100MHz at the -3dB standard in the red light band; even better, it achieved a modulation bandwidth greater than 1GHz at the -3dB standard. This performance level successfully breaks through the traditional bottleneck of bandwidth limitation in high-In composition devices, enabling them to perform well in high-speed optical communication applications at long wavelengths.

[0059] The specific structure, function, and role of the light-emitting diode can be referred to in Embodiment 1, and will not be repeated here.

[0060] Example 3 This invention also provides a communication system employing the light-emitting diode (LED) described in Embodiment 1 above, which is particularly suitable for visible light communication (VLC) scenarios and can be widely used in indoor high-speed network access and other fields. Compared to conventional visible light communication systems, long-wavelength devices suffer from numerous interface defects, narrow modulation bandwidth, and rapid signal attenuation due to high In composition, making it difficult to break through the Gbps level bottleneck in data transmission rates. This embodiment, through innovative design of the LED, enables it to have a wider modulation bandwidth, lower signal distortion, and more stable light-emitting characteristics, achieving a breakthrough in data transmission rates greater than 1Gbps for the communication system, ensuring high-speed, reliable, and stable data transmission.

[0061] For details regarding the structure, function, and role of light-emitting diodes, please refer to Embodiment 1, which will not be repeated here.

[0062] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0063] Although terms such as cover layer and active layer are frequently used in this document, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the specification, claims, and accompanying drawings of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting diode, characterized in that: It includes a substrate and a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the substrate; The active layer includes at least one set of periodically alternating quantum well layers and quantum barrier layers; the quantum well layers contain an In composition; the active layer also includes at least one capping layer; the capping layer is located between the quantum well layers and the quantum barrier layers; the material of the capping layer is selected from group III-V nitride semiconductor materials, and the bond energy of the chemical bond formed between the metal element and the nitrogen element in the group III-V nitride semiconductor material is higher than the In-N bond energy formed between the indium element and the nitrogen element in the quantum well layer.

2. The light-emitting diode according to claim 1, characterized in that: The material of the capping layer is selected from one or more of GaN, AlGaN, and AlInGaN.

3. The light-emitting diode according to claim 1, characterized in that: The thickness of the capping layer is less than the thickness of the quantum well layer, or the thickness of the capping layer is less than the thickness of the quantum barrier layer, or the thickness of the capping layer is less than both the thickness of the quantum well layer and the thickness of the quantum barrier layer.

4. The light-emitting diode according to claim 1, characterized in that: The In content in the quantum well layer is between 0.10 and 0.45, and the emission wavelength of the light-emitting diode is between 500 nm and 750 nm.

5. The light-emitting diode according to claim 2, characterized in that: When the material of the covering layer is selected from Al x Ga （1-x） When N is constant, 0.03 < x < 0.7; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.03 < y < 0.

7.

6. The light-emitting diode according to claim 2, characterized in that: When the material of the covering layer is selected from Al x Ga （1-x） When N is constant, 0.1 < x < 0.3; when the material of the covering layer is selected from Al... y In z Ga （1-y-z） When N is constant, 0.1 < y < 0.

3.

7. The light-emitting diode according to claim 1, characterized in that: The thickness of the covering layer is between 0.5 nm and 3 nm.

8. The light-emitting diode according to any one of claims 1 to 7, characterized in that: During the growth of the active layer, an interface interruption process is performed at the quantum well layer interface, the capping layer interface, or the interface between the two. The interface interruption process involves stopping the supply of the metal-organic source and introducing a processing gas. The processing gas is selected from any one or a mixture of nitrogen, hydrogen, and ammonia.

9. The light-emitting diode according to claim 8, characterized in that: The root mean square roughness of the interface of the quantum well layer is less than 3 nm.

10. The light-emitting diode according to claim 8, characterized in that: The root mean square roughness of the interface of the quantum well layer is less than 0.5 nm.

11. The light-emitting diode according to claim 8, characterized in that: The modulation bandwidth of the light-emitting diode under the −3dB standard is greater than 100MHz.

12. The light-emitting diode according to claim 8, characterized in that: The modulation bandwidth of the light-emitting diode under the −3dB standard is greater than 1GHz.

13. The light-emitting diode according to claim 1, characterized in that: The second semiconductor layer includes an electron blocking layer and a p-type nitride layer. The electron blocking layer is located above the active layer and is made of a wide bandgap material. The p-type nitride layer can be selected from GaN or InGaN.

14. The light-emitting diode according to claim 1, characterized in that: The light-emitting diode further includes a transparent electrode and an n-type electrode. The transparent electrode is located on the light-emitting side of the light-emitting diode and is electrically connected to the second semiconductor layer. The n-type electrode is located on the non-light-emitting side of the light-emitting diode and is electrically connected to the first semiconductor layer.

15. A method for fabricating a light-emitting diode, characterized in that, Includes the following steps: Provide substrate; A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially grown on the substrate; wherein, the active layer includes at least one set of periodically alternating quantum well layers and quantum barrier layers; the quantum well layers contain an In composition; the active layer further includes at least one capping layer, the capping layer being located between the quantum well layers and the quantum barrier layers; During the growth of the active layer, at least one interface interruption process is performed, which includes stopping the supply of the metal-organic source and introducing a processing gas, wherein the processing gas is selected from any one or a mixture of nitrogen, hydrogen, and ammonia. The timing for executing the interface interruption handling is selected from at least one of the following: After the quantum well layer has been grown, but before the corresponding capping layer has been grown; After at least one of the capping layers has been grown, but before the corresponding quantum barrier layer has been grown; After the quantum well layer is grown and the interface interruption process is executed, another capping layer is grown, but before the corresponding quantum barrier layer is grown.

16. The method for fabricating a light-emitting diode according to claim 15, characterized in that: The processing time of the interface interruption process is between 1s and 80s, the temperature of the interface interruption process is between 500℃ and 1000℃, and the flow rate of the processing gas is between 500 sccm and 100000 sccm; or the processing time of the interface interruption process is between 2s and 30s, the temperature of the interface interruption process is between 700℃ and 900℃, and the flow rate of the processing gas is between 500 sccm and 5000 sccm.

17. The method for fabricating a light-emitting diode according to claim 15, characterized in that: The material of the capping layer is selected from group III-V nitride semiconductor materials. The bond energy of the chemical bond formed between the metal element and nitrogen element in the group III-V nitride semiconductor material is higher than the In-N bond energy formed between indium element and nitrogen element in the quantum well layer.

18. A communication system, characterized in that: The communication system includes a light-emitting diode as described in any one of claims 1-14, and the data transmission rate of the communication system is greater than 1Gbps.

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