Light emitting diode structure and preparation method, display chip, and optical communication light source

Abstract

The application relates to the technical field of semiconductors, and discloses a light-emitting diode structure, a preparation method, a display chip and an optical communication light source. The light-emitting diode structure comprises a substrate, a first reflecting film, a second reflecting film and a light-emitting layer. The first reflecting film and the second reflecting film are arranged above the substrate in a spaced manner, and a resonant cavity is formed between the first reflecting film and the second reflecting film. The light-emitting layer is arranged in the resonant cavity, and the light-emitting layer comprises a plurality of LED units arranged in an array. The application can reduce multi-channel optical communication signal crosstalk, effectively suppress wavelength drift caused by temperature rise, and improve the working stability and signal reliability of multi-channel optical communication.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, specifically relating to a light-emitting diode structure and its fabrication method, a display chip, and an optical communication emission source. Background Technology

[0002] Optical communication is a high-speed communication technology that uses light waves as the transmission medium. During transmission, the transmitting end converts the data to be transmitted into an electrical signal and modulates the light source with the electrical signal, causing the output light intensity to dynamically change with the electrical signal, thereby loading information onto the light wave. The modulated optical signal carrying the information is transmitted through optical fiber to the receiving end. The receiving end uses optoelectronic devices to restore the optical signal to an electrical signal, and after analysis and demodulation, recovers the original data, completing the high-speed information transmission.

[0003] In optical communication, a light-emitting diode (LED) with a resonant cavity can be used as the signal transmission light source.

[0004] In related technologies, the resonant cavity is located inside a single LED unit. Each LED unit requires a separately patterned distributed Bragg reflector (DBR) film. Differences in film processing lead to significant differences in wavelength and output power among the array units, making multi-channel parallel communication prone to signal crosstalk. Furthermore, the thermal expansion coefficients of the built-in DBR and the semiconductor epitaxial layer are mismatched, making the interface susceptible to damage and reducing reflectivity after the device heats up. Temperature rise also causes significant wavelength drift, resulting in poor communication stability. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the related art.

[0006] A first aspect of this application provides a light-emitting diode structure, including a substrate; a first reflective film and a second reflective film, the first reflective film and the second reflective film being disposed at a distance above the substrate, and a resonant cavity being formed between the first reflective film and the second reflective film; and a light-emitting layer disposed within the resonant cavity, the light-emitting layer including a plurality of LED units arranged in an array.

[0007] In one optional embodiment, the first reflective film is disposed on the upper surface of the substrate and located between the substrate and the second reflective film; the peak reflectivity of the first reflective film to the target wavelength is higher than that of the second reflective film to the target wavelength.

[0008] In one alternative embodiment, the first reflective film and the second reflective film are distributed Bragg reflective films, respectively.

[0009] In one alternative embodiment, the LED unit includes an LED mesa, which includes a first doped semiconductor layer and an active layer stacked thereon; and a second doped semiconductor layer stacked above the active layer, at least a portion of which extends out of the LED mesa.

[0010] In one optional embodiment, the light-emitting layer further includes a transparent conductive layer surrounding the outside of the LED mesa, the transparent conductive layer being electrically connected to the first doped semiconductor layer of the LED mesa, and the transparent conductive layer including a connection end extending laterally outward from the LED mesa.

[0011] In one optional embodiment, the substrate includes a first contact and a second contact, the light-emitting layer further includes a pad disposed on the side of the LED mesa, the portion of the second doped semiconductor layer extending out of the LED mesa rests on the pad and is electrically connected to the pad; a first conductive post penetrates the connection end of the transparent conductive layer and is electrically connected to the first contact; a second conductive post penetrates the pad and is electrically connected to the second contact.

[0012] In one alternative embodiment, the material of the pad is the same as the material of the transparent conductive layer; the thickness of the pad is the same as the thickness of the connection end of the transparent conductive layer.

[0013] In one optional embodiment, the light-emitting diode structure further includes a passivation layer disposed on the surface of the LED unit near the substrate and extending between adjacent LED units; a leveling layer filling the spaces between adjacent LED units and covering the transparent conductive layer, wherein the first reflective film is disposed on the side of the leveling layer away from the LED unit; and a planarization layer disposed above the passivation layer, wherein the second reflective film is disposed on the top of the planarization layer.

[0014] A second aspect of this application provides a display chip, the display chip comprising the light-emitting diode structure as described above.

[0015] A third aspect of this application provides an optical communication emitting light source, which includes the light-emitting diode structure as described above.

[0016] A fourth aspect of this application provides a method for fabricating a light-emitting diode (LED) structure, which is used to fabricate the LED structure as described above. The fabrication method includes the following steps: providing a substrate; preparing a light-emitting layer, the light-emitting layer including a plurality of LED units arranged in an array; forming a first reflective film on one side surface of the light-emitting layer; disposing the first reflective film above the substrate; forming a second reflective film above the light-emitting layer, such that the first reflective film and the second reflective film are spaced apart above the substrate, and the light-emitting layer is located in a resonant cavity between the first reflective film and the second reflective film.

[0017] In one optional embodiment, the step of preparing the light-emitting layer includes: preparing a substrate, wherein an LED epitaxial layer is disposed on one side of the substrate, the LED epitaxial layer including a first doped semiconductor layer, an active layer and a second doped semiconductor layer stacked thereon, the second doped semiconductor layer being disposed on the surface of the substrate, the first doped semiconductor layer and the active layer being etched to form a plurality of LED mesa arranged in an array; forming a passivation layer on the surface of the LED mesa and the second doped semiconductor layer, the passivation layer having a first window exposing the first doped semiconductor layer and a second window exposing the second doped semiconductor layer, the second window being located on the side of the LED mesa; forming a transparent conductive layer and pads, the transparent conductive layer surrounding the outside of the LED mesa and filling the first window to electrically connect with the first doped semiconductor layer, the transparent conductive layer including a connection end extending laterally outward from the LED mesa; the pads filling the second window and electrically connecting with the second doped semiconductor layer; forming a leveling layer, the leveling layer filling between adjacent LED units and covering the transparent conductive layer.

[0018] In one alternative embodiment, the step of forming a first reflective film on one side of the light-emitting layer includes: forming a first reflective film on the surface of the leveling layer away from the substrate.

[0019] In an optional embodiment, the substrate includes a first contact and a second contact. Before forming a second reflective film above the light-emitting layer, the fabrication method further includes: removing the substrate and a portion of the second doped semiconductor layer to form a plurality of LED units arranged in an array and exposing a portion of the surface of a passivation layer, wherein the second doped semiconductor layer of each LED unit is disposed on a corresponding pad; forming a planarization layer above the passivation layer; forming a first via at least penetrating the connection end of the transparent conductive layer and a second via at least penetrating the pad, wherein the first via exposes the first contact and the second via exposes the second contact, and at least equal etching rates are achieved through the connection end and the pad; forming a first conductive pillar in the first via and forming a second conductive pillar in the second via.

[0020] In one alternative embodiment, the step of forming a second reflective film over the light-emitting layer includes: forming a second reflective film over the planarization layer.

[0021] The light-emitting diode structure and fabrication method, display chip, and optical communication emitting light source provided in this application can achieve at least the following technical effects: In this embodiment, the first reflective film and the second reflective film are spaced apart to form a resonant cavity between them. A light-emitting layer is disposed within the resonant cavity, comprising multiple LED units arranged in an array. In other words, a global resonant cavity is constructed using the entire first and second reflective films. The multiple LED units of the light-emitting layer are located within this global resonant cavity, allowing the LED unit array to share a unified resonant optical environment. This results in a high degree of consistency in the output spectrum and optical power of each LED unit, significantly reducing wavelength drift differences caused by temperature rise and effectively reducing crosstalk in multi-channel optical communication signals. The first and second reflective films are located outside the LED array, avoiding the mismatch in thermal expansion coefficients between the DBR and the semiconductor epitaxial layer. When the device operates at high speed and generates heat, the DBR film structure remains stable, and the reflectivity remains stable over a long period. It also effectively suppresses wavelength drift caused by temperature rise, improving the operational stability and signal reliability of multi-channel optical communication, thereby enhancing the signal transmission stability and quality of the optical communication system. Furthermore, the global resonant reflection structure can recover scattered light energy at the gaps between LED units, converging the beam and reducing the divergence angle, thus improving overall light extraction efficiency and fiber coupling efficiency. The integrally formed first reflective film and integrally formed second reflective film can simplify photolithography, patterning and other processes, balance the overall etching rate, reduce process defects and improve device yield.

[0022] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present disclosure; Figure 2 A schematic diagram of the structure in the process of preparing the light-emitting layer provided in the embodiments of this disclosure. Figure 1 ; Figure 3 A schematic diagram of the structure in the process of preparing the light-emitting layer provided in the embodiments of this disclosure. Figure 2 ; Figure 4 A schematic diagram of the structure in the process of preparing the light-emitting layer provided in the embodiments of this disclosure. Figure 3 ; Figure 5 A schematic diagram of the structure in the process of preparing the light-emitting layer provided in the embodiments of this disclosure. Figure 4 ; Figure 6 This is a schematic diagram of a structure in which a first reflective film is formed on one side of the light-emitting layer, according to an embodiment of the present disclosure. Figure 7 A schematic diagram of the structure for disposing the first reflective film on the substrate according to an embodiment of this disclosure. Figure 1 ; Figure 8 A schematic diagram of the structure for disposing the first reflective film on the substrate according to an embodiment of this disclosure. Figure 2 ; Figure 9 A schematic diagram of the structure for disposing the first reflective film on the substrate according to an embodiment of this disclosure. Figure 3 ; Figure 10 A schematic diagram of the structure for disposing the first reflective film on the substrate according to an embodiment of this disclosure. Figure 4 ; Figure 11 A flowchart illustrating a method for fabricating a light-emitting diode structure according to an embodiment of this disclosure.

[0024] The reference numerals in the attached figures are as follows: 100: Light-emitting diode structure; 10: Substrate; 11: First contact; 12: Second contact; 13: First reflective film; 14: Second reflective film; 20: Light-emitting layer; 21: LED unit; 22: LED mesa; 23: Second doped semiconductor layer; 24: Transparent conductive layer; 25: Connector; 26: Pad; 27: First conductive post; 28: Second conductive post; 30: Passivation layer; 31: First window; 32: Second window; 33: Fill layer; 34: Planarization layer; 40: Substrate; 41: LED epitaxial layer; 50: First through hole; 51: Second through hole. Detailed Implementation

[0025] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0026] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0027] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0028] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0029] Unless otherwise stated, the term "multiple" means two or more.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0031] As used in embodiments of this disclosure, the term "layer" refers to a portion of material comprising a region having a certain thickness. A layer may extend over the entire lower or upper structure, or may have a extent smaller than that of the lower or upper structure. A layer may extend horizontally, vertically, and / or along a tapered surface.

[0032] Combination Figure 1 As shown, this embodiment of the present disclosure provides a light-emitting diode structure 100, including a substrate 10, a first reflective film 13, a second reflective film 14, and a light-emitting layer 20. The first reflective film 13 and the second reflective film 14 are disposed at intervals above the substrate 10, and a resonant cavity is formed between the first reflective film 13 and the second reflective film 14. The light-emitting layer 20 is disposed within the resonant cavity, and the light-emitting layer 20 includes a plurality of LED units 21 arranged in an array.

[0033] The substrate 10 may be provided with a circuit layer including complementary metal oxide semiconductor (CMOS) devices or thin film transistor (TFT) devices, which can constitute a driving circuit. In some embodiments, the substrate 10 includes a first contact 11 and a second contact 12.

[0034] The first reflective film 13 and the second reflective film 14 are spaced apart and disposed above the substrate 10, that is, the first reflective film 13 and the second reflective film 14 are spaced apart and located above the substrate 10. The spaced arrangement of the first reflective film 13 and the second reflective film 14 forms a resonant cavity between them. A light-emitting layer 20 is disposed within the resonant cavity, and the light-emitting layer 20 includes a plurality of LED units 21 arranged in an array. In other words, a global resonant cavity is constructed through the entire first reflective film 13 and the entire second reflective film 14. The plurality of LED units 21 of the light-emitting layer 20 are disposed within the global resonant cavity, allowing the LED unit array 21 to share a unified resonant optical environment. This results in a high degree of consistency between the output spectrum and optical power of each LED unit 21, significantly reducing wavelength drift differences caused by temperature rise and effectively suppressing crosstalk in multi-channel optical communication signals.

[0035] The first reflective film 13 and the second reflective film 14 are disposed outside the LED array, which avoids the mismatch of the thermal expansion coefficients between the DBR and the semiconductor epitaxial layer. When the device is operating at high speed and generating heat, the DBR film structure is stable and the reflectivity can remain stable for a long time. It can also effectively suppress the wavelength drift caused by temperature rise, thereby improving the working stability and signal reliability of multi-channel optical communication, and thus improving the signal transmission stability and transmission quality of the optical communication system.

[0036] Furthermore, the global resonant reflection structure can recover scattered light energy at the gaps between LED units 21, converge the beam to reduce the divergence angle, and improve the overall light extraction efficiency and fiber coupling efficiency. The integrally formed first reflective film 13 and integrally formed second reflective film 14 can also simplify photolithography, patterning and other processes, balance the overall etching rate, reduce process defects, and improve device yield.

[0037] Furthermore, the multiple LED units 21 arranged in the array enable independent light emission output through multiple channels, meeting the requirements of high-speed parallel optical communication for multi-channel signal transmission. By placing the light-emitting layer 20 within the resonant cavity, the first reflective film 13 and the second reflective film 14 can constrain the photons generated by the LED units 21 to oscillate and amplify within the resonant cavity, improving the directional light power and beam convergence, thereby enhancing the optical communication path coupling efficiency. Moreover, the resonant cavity can also perform spectral filtering, optimizing the monochromaticity of the output light and further reducing wavelength interference between multiple signals.

[0038] In some embodiments, a first reflective film 13 is disposed on the upper surface of a substrate 10 and located between a substrate 10 and a second reflective film 14. The peak reflectivity of the first reflective film 13 for the target wavelength is higher than that of the second reflective film 14 for the target wavelength.

[0039] like Figure 1 As shown, the substrate 10, the first reflective film 13, the light-emitting layer 20, and the second reflective film 14 are sequentially stacked from bottom to top. The first reflective film 13 is fused and bonded to the top of the substrate 10, which improves the bonding interface strength and sealing, optimizes the uniformity of the reflective interface, and achieves efficient oscillation gain of photons in the resonant cavity.

[0040] By utilizing the higher peak reflectivity of the first reflective film 13 for the target wavelength compared to the second reflective film 14, an asymmetric resonant cavity with high reflectivity at the bottom and low reflectivity at the top is constructed, thereby improving beam directionality and optical signal coupling efficiency. Specifically, the first reflective film 13 and the second reflective film 14 work together to increase the oscillation gain of photons within the resonant cavity. The amplified photons of the target wavelength are then emitted outward through the second reflective film 14, simultaneously achieving optical amplification and directional light emission.

[0041] For example, the first reflective film has a peak reflectivity of 99.5% or higher for the target wavelength, which can form a high reflectivity constraint for the light propagating downward in the resonant cavity. The second reflective film has a peak reflectivity of 65% to 90% for the target wavelength. On the one hand, it maintains the resonant gain condition in the cavity by reflecting some photons, thereby achieving spectral narrowing and optical field amplification. On the other hand, it allows the light beam matching the resonant wavelength to be transmitted outward and output, forming a usable output optical signal.

[0042] In some embodiments, the first reflective film 13 and the second reflective film 14 are distributed Bragg reflective films, respectively.

[0043] The first reflective film 13 and the second reflective film 14 are distributed Bragg reflection films to form a global resonant cavity, so that the output spectrum and optical power of each LED unit are highly consistent, significantly reducing the wavelength drift difference caused by temperature rise, and more effectively suppressing crosstalk of multi-channel optical communication signals. They also enable the corresponding light rays to be constrained to oscillate and amplify within the resonant cavity, improving beam directionality, increasing directional output light intensity, and reducing light energy loss.

[0044] Distributed Bragg Reflector (DBR) is an optical reflection structure composed of periodic refractive index modulation. It forms an optical mirror with high reflectivity for a specific wavelength by alternately stacking two dielectric layers with different refractive indices within a material. The two dielectric layers with different refractive indices are a high-refractive-index layer and a low-refractive-index layer.

[0045] The peak reflectivity of a DBR at the target wavelength is determined by the refractive index difference between the high-refractive-index layer and the low-refractive-index layer, as well as the number of stacking periods. Assuming consistent optical thickness and stacking periods, a greater refractive index difference between the high- and low-refractive-index layers results in a higher peak reflectivity for the DBR.

[0046] In some embodiments, combined with Figure 1 as well as Figures 8 to 10 As shown, the LED unit 21 includes an LED mesa 22 and a second doped semiconductor layer 23. The LED mesa 22 includes a first doped semiconductor layer and an active layer stacked together. The second doped semiconductor layer 23 is stacked above the active layer, and at least a portion of the second doped semiconductor layer 23 extends out of the LED mesa 22.

[0047] Specifically, the LED unit 21 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer 23 stacked together, so that each LED unit 21 can be an independent light-emitting unit. The first doped semiconductor layer of the LED unit 21 can be a p-type semiconductor layer, such as p-type gallium nitride (GaN), and the second doped semiconductor layer 23 can be an n-type semiconductor layer, such as n-type gallium nitride (GaN).

[0048] The second doped semiconductor layer 23 is stacked on top of the active layer, and at least a portion of the second doped semiconductor layer 23 extends out of the LED mesa 22, expanding the external conductive contact area and simplifying the etching process.

[0049] In some embodiments, combined with Figure 1 as well as Figures 5 to 10 As shown, the light-emitting layer 20 also includes a transparent conductive layer 24, which surrounds the outside of the LED mesa 22. The transparent conductive layer 24 is electrically connected to the first doped semiconductor layer of the LED mesa 22, and the transparent conductive layer 24 includes a connection end 25 extending laterally to the outside of the LED mesa 22.

[0050] A transparent conductive layer 24 surrounds the outside of the LED mesa 22 and is electrically connected to the first doped semiconductor layer of the LED mesa 22, which can increase the conductive contact area and reduce the contact resistance. The transparent conductive layer 24 includes a connection end 25 extending laterally outward from the LED mesa 22 to bring out the electrical connection position of the LED unit 21, reducing the processing difficulty. Here, "lateral extension" refers to an extension direction parallel or approximately parallel to the upper surface of the substrate 10.

[0051] In one alternative embodiment, the transparent conductive layer 24 is made of a transparent material, which allows the light beam to pass through smoothly, reduces light energy loss, and realizes efficient light oscillation amplification in the resonant cavity, thus meeting the high output requirements of optical communication light sources.

[0052] In some embodiments, combined with Figure 1 and Figure 10 As shown, the substrate 10 includes a first contact 11 and a second contact 12, and the light-emitting layer 20 also includes a pad 26, a first conductive pillar 27, and a second conductive pillar 28. The pad 26 is disposed on the side of the LED mesa 22, and a portion of the second doped semiconductor layer 23 extending out of the LED mesa 22 rests on the pad 26 and is electrically connected to the pad 26. The first conductive pillar 27 penetrates the connection end 25 of the transparent conductive layer 24 and is electrically connected to the first contact 11. The second conductive pillar 28 penetrates the pad 26 and is electrically connected to the second contact 12.

[0053] The substrate 10 includes a plurality of first contacts 11 and a plurality of second contacts 12. Each first contact 11 and a second contact 12 is electrically connected to the corresponding two-end electrodes of an LED unit 21, so that each LED unit 21 is independently driven to emit light by the substrate 10.

[0054] The second doped semiconductor layer 23 of the LED unit 21 extends out of the LED mesa 22 and is placed on the pad 26 and electrically connected to the pad 26, forming a stable electrical connection between the second doped semiconductor layer 23 and the pad 26. This increases the conductive contact area, reduces the contact resistance, balances the current distribution on the LED mesa 22, and improves the electrical consistency of the array device.

[0055] The first conductive post 27 penetrates the planarization layer 34, the passivation layer 30, the connection end 25 of the transparent conductive layer 24, the leveling layer 33, and the first reflective film 13. The first conductive post 27 is electrically connected to the connection end 25 of the transparent conductive layer 24 and the corresponding first contact 11, respectively, thus realizing the electrical connection between the first contact 11 of the substrate 10 and the first doped semiconductor layer of the LED unit 21. The second conductive post 28 penetrates the planarization layer 34, the pad 26, the leveling layer 33, and the first reflective film 13, so that the second doped semiconductor layer 23 of the LED unit 21 is electrically connected to the second conductive post 28 through the pad 26, and is electrically connected to the corresponding second contact 12 through the second conductive post 28. This realizes that the first contact 11 and the second contact 12 are respectively electrically connected to the two end electrodes of the LED unit 21, so that each LED unit 21 can be individually driven to emit light by the substrate 10.

[0056] In some embodiments, combined with Figure 1 As shown, the material of pad 26 is the same as that of transparent conductive layer 24. The thickness of pad 26 is the same as the thickness of connection end 25 of transparent conductive layer 24.

[0057] Figure 1 In the diagram, 'a' indicates the thickness of the pad, and 'b' indicates the thickness of the connection end of the transparent conductive layer. By using the same material for the pad 26 and the transparent conductive layer 24, and by ensuring that the thickness of the pad 26 is the same as the thickness of the connection end 25 of the transparent conductive layer 24, a balanced etching rate is achieved, ensuring complete conductive contact, improving the consistency of the array's electrical and optical parameters, increasing production yield, and also enabling light transmission to stabilize the amplification effect of the resonant cavity's optical path. The thickness is the film dimension measured along a direction perpendicular to the upper surface of the substrate 10.

[0058] The materials of the pad 26 and the transparent conductive layer 24 include transparent conductive oxide (TCO), such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or aluminum-doped zinc oxide (AZO).

[0059] In some embodiments, combined with Figure 1 as well as Figures 4 to 10 As shown, the light-emitting diode structure 100 further includes a passivation layer 30, a filler layer 33, and a planarization layer 34. The passivation layer 30 is deposited on the surface of the LED unit 21 near the substrate 10 and extends between adjacent LED units 21. The filler layer 33 fills the spaces between adjacent LED units 21 and covers the transparent conductive layer 24. A first reflective film 13 is disposed on the side of the filler layer 33 away from the LED unit 21. The planarization layer 34 is disposed above the passivation layer 30, and a second reflective film 14 is disposed on the top of the planarization layer 34.

[0060] A passivation layer 30 is deposited on the surface of the LED unit 21 near the substrate 10 and extends between adjacent LED units 21 to achieve insulation and prevent crosstalk of multiple optical communication signals. The material of the passivation layer 30 can be alumina or silicon dioxide.

[0061] The leveling layer 33 fills the space between adjacent LED units 21 and covers the transparent conductive layer 24 to achieve leveling, providing a flat base for the first reflective film 13 to be disposed on one side of the leveling layer 33.

[0062] By placing the planarization layer 34 above the passivation layer 30, planarization is achieved, providing a flat deposition substrate for the formation of the second reflective film 14 on the top of the planarization layer 34, so that the optical performance of the second reflective film 14 is uniform and stable.

[0063] This disclosure also provides a display chip, which includes the light-emitting diode structure 100 as described above. Therefore, the display chip possesses all the technical effects of the light-emitting diode structure 100 as described above, and will not be repeated here.

[0064] The light-emitting diode structure 100 or display chip can be applied to devices such as augmented reality (AR) display devices, virtual reality (VR) display devices, near-eye display (NED) devices, and head-up display (HUD) devices.

[0065] In the display field, the LED structure 100 features a resonant cavity. Through photon oscillation within the cavity, it filters narrow-band spectra, effectively improving the purity of pixel emission colors and widening the display color gamut. Simultaneously, the global resonant cavity can recover stray light within the device, improving photon extraction efficiency and reducing the display's power consumption. Furthermore, the array pixels share a unified resonant environment, resulting in higher brightness and wavelength consistency among sub-pixels. The screen exhibits no significant color shift even after long-term illumination, and its compact overall structure makes it suitable for ultra-high pixel density micro-displays and small-pitch high-definition display scenarios.

[0066] This disclosure also provides an optical communication transmitting light source, which includes the light-emitting diode structure 100 as described above.

[0067] In the field of optical communication, compared to laser light sources, optical communication emission sources using light-emitting diode (LED) structures offer significant advantages in terms of low power consumption. Furthermore, multi-unit array integration enables parallel transmission and spatial multiplexing of multiple optical signals, effectively increasing the overall transmission rate of optical communication and adapting to high-density parallel optical communication deployment scenarios. Moreover, this embodiment effectively optimizes key communication parameters such as the device's emission spectrum linewidth, emission directionality, modulation bandwidth, and wavelength stability through a global resonant cavity structure, improving fiber coupling efficiency, suppressing optical parameter drift caused by device operating temperature rise, significantly enhancing the transmission quality and efficiency of parallel optical communication, and effectively extending the optical communication transmission distance.

[0068] Combination Figure 11 The present disclosure also provides a method for fabricating a light-emitting diode (LED) structure, used to fabricate the LED structure 100 as described above. The fabrication method includes the following steps: S1101, Provide a substrate.

[0069] The substrate 10 includes a first contact 11 and a second contact 12. For example, the first contact 11 may be an anode metal contact, and the second contact 12 may be a cathode metal contact.

[0070] S1102. Prepare the light-emitting layer, which includes multiple LED units arranged in an array.

[0071] Multiple LED units 21 arranged in an array achieve multi-channel independent light emission.

[0072] In some embodiments, the step of preparing the light-emitting layer 20 includes: preparing a substrate 40, wherein an LED epitaxial layer 41 is disposed on one side of the substrate 40, the LED epitaxial layer 41 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked thereon, the second doped semiconductor layer being disposed on the surface of the substrate 40, and the first doped semiconductor layer and the active layer being etched to form a plurality of LED mesa 22 arranged in an array. A passivation layer 30 is formed on the surface of the LED mesa 22 and the second doped semiconductor layer, the passivation layer 30 having a first window 31 exposing the first doped semiconductor layer and a second window 32 exposing the second doped semiconductor layer, the second window 32 being located on the side of the LED mesa 22. A transparent conductive layer 24 and pads 26 are formed, the transparent conductive layer 24 surrounding the outside of the LED mesa 22 and filling the first window 31 for electrical connection with the first doped semiconductor layer, the transparent conductive layer 24 including a connection end 25 extending laterally outward from the LED mesa 22. The pads 26 are filled within the second window 32 and are electrically connected to the second doped semiconductor layer. A filler layer 33 is formed, which fills the spaces between adjacent LED units 21 and covers a transparent conductive layer 24.

[0073] Among them, combined Figure 2 and Figure 3 As shown, the LED epitaxial layer 41 can be a gallium nitride (GaN) epitaxial layer. The LED epitaxial layer 41 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked together, with the second doped semiconductor layer disposed on one side of the substrate 40. The first doped semiconductor layer and the active layer of the LED epitaxial layer 41 can be etched using a mesa etching process (MESA) to form a plurality of LED mesa 22 arranged in an array, such that each LED mesa 22 has a first doped semiconductor layer and an active layer, and the plurality of LED mesa 22 are arranged in an array on one side of the entire second doped semiconductor layer.

[0074] Combination Figure 4 As shown, aluminum oxide (Al2O3) or silicon dioxide (SiO2) is deposited on the surface of the LED mesa 22 and the entire second doped semiconductor layer to form a passivation layer 30. A first window 31 is formed in the passivation layer 30 to expose the first doped semiconductor layer, providing a connection area for the electrical connection between the transparent conductive layer 24 and the first doped semiconductor layer of the LED mesa 22. A second window 32 is also formed in the passivation layer 30 to expose the second doped semiconductor layer. The second window 32 is located on the side of the LED mesa 22 to provide a location for forming the pad 26.

[0075] Combination Figure 5 As shown, an indium tin oxide (ITO) thin film is deposited and patterned on the passivation layer 30 to form a transparent conductive layer 24 and pads 26. The transparent conductive layer 24 surrounds the exterior of the LED mesa 22 and fills the first window 31 for electrical connection with the first doped semiconductor layer. The transparent conductive layer 24 includes connection terminals 25 extending laterally outward from the LED mesa 22. The pads 26 fill the second window 32 and are electrically connected to the second doped semiconductor layer.

[0076] Combination Figure 6 As shown, a filler layer 33 is formed by depositing a thick oxide layer and performing chemical mechanical polishing (CMP). The filler layer 33 fills the spaces between adjacent LED units 21 and covers the transparent conductive layer 24, providing a flat substrate for forming the first reflective film 13 and also achieving electrical isolation between LED mesa 22.

[0077] S1103. A first reflective film is formed on one side of the surface of the light-emitting layer.

[0078] Combination Figure 6 As shown, a first reflective film 13 is formed on one side of the surface of the light-emitting layer 20, providing a reflective structure for constructing the resonant cavity. In the resonant cavity structure, the first reflective film 13 can reflect downward-escaped photons back into the resonant cavity for continuous oscillation and amplification, thereby increasing the directional output optical power.

[0079] In some embodiments, the step of forming a first reflective film 13 on one side of the light-emitting layer 20 includes forming a first reflective film 13 on the surface of the leveling layer 33 away from the substrate 40. Specifically, the first reflective film 13 is formed on the surface of the leveling layer 33 away from the substrate 40 by selective deposition.

[0080] S1104. The first reflective film is disposed on the top of the substrate.

[0081] Combination Figure 7 As shown, by placing the first reflective film 13 above the substrate 10, the first reflective film 13 and the light-emitting layer 20 are disposed on the substrate 10. Specifically, the first reflective film 13 is fused and bonded to the top of the substrate 10 to reduce light absorption, thereby continuously ensuring the optical oscillation amplification efficiency of the resonant cavity.

[0082] In some embodiments, the substrate 10 includes a first contact 11 and a second contact 12. Before forming the second reflective film 14 above the light-emitting layer 20, the fabrication method further includes: removing the substrate 40 and a portion of the second doped semiconductor layer 23 to form a plurality of LED units 21 arranged in an array and exposing a portion of the surface of the passivation layer 30, wherein the second doped semiconductor layer 23 of each LED unit 21 is disposed on a corresponding pad 26. A planarization layer 34 is formed above the passivation layer 30. A first via 50 at least penetrating the connection terminal 25 of the transparent conductive layer 24 and a second via 51 at least penetrating the pad 26 are formed. The first via 50 exposes the first contact 11, and the second via 51 exposes the second contact 12. At least a uniform etching rate is achieved through the connection terminal 25 and the pad 26. A first conductive post 27 is formed in the first via 50, and a second conductive post 28 is formed in the second via 51.

[0083] Combination Figure 7 and Figure 8 As shown, the substrate 40 is removed, and the second doped semiconductor layer 23 is removed by etching the second doped semiconductor layer 41 of the LED epitaxial layer 41 to form a plurality of LED units 21 arranged in an array. The surface of part of the passivation layer 30 is also exposed, so that the second doped semiconductor layer 23 of each LED unit 21 is placed on the corresponding pad 26, realizing the electrical connection between the second doped semiconductor layer 23 of the LED unit 21 and the corresponding pad 26, simplifying the processing technology.

[0084] Combination Figure 9As shown, an oxide layer is deposited above the passivation layer 30 to form a planarization layer 34. A first via 50 is formed through via patterning, penetrating the planarization layer 34, the passivation layer 30, the transparent conductive layer 24, the filler layer 33, and the first reflective film 13. A second via 51 is also formed, penetrating the planarization layer 34, the pad 26, the filler layer 33, and the first reflective film 13, so that at least a uniform etching rate is achieved through the connection end 25 and the pad 26. The first via 50 exposes the first contact 11, and the second via 51 exposes the second contact 12.

[0085] Combination Figure 10 As shown, copper or tungsten is filled in the first through hole 50 to form a first conductive pillar 27, and copper or tungsten is filled in the second through hole 51 to form a second conductive pillar 28. Surface chemical mechanical polishing (CMP) is performed to achieve surface planarization, so that the first contact 11 and the second contact 12 are respectively electrically connected to the two end electrodes of the LED unit 21, so that each LED unit 21 can be driven to emit light individually by the substrate 10. The processing technology is simple and the yield of the device is improved.

[0086] S1105. A second reflective film is formed above the light-emitting layer, such that the first reflective film and the second reflective film are spaced apart above the substrate, and the light-emitting layer is located in the resonant cavity between the first reflective film and the second reflective film.

[0087] By forming a second reflective film 14 above the light-emitting layer 20, the first reflective film 13 and the second reflective film 14 are spaced apart to form a resonant cavity, and the light-emitting layer 20 is located in the resonant cavity, the fabrication of the light-emitting diode structure 100 is completed. The process is simple, the processing difficulty is reduced, and the yield is improved.

[0088] In some embodiments, the step of forming a second reflective film 14 over the light-emitting layer 20 includes forming a second reflective film 14 over the planarization layer 34.

[0089] Combination Figure 1 As shown, by forming a second reflective film 14 above the planarization layer 34, the second reflective film 14 is positioned above the light-emitting layer 20, thereby positioning the light-emitting layer 20 within the resonant cavity between the first reflective film 13 and the second reflective film 14.

[0090] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A light-emitting diode structure, characterized in that, include: substrate; A first reflective film and a second reflective film are disposed at a distance above the substrate, and a resonant cavity is formed between the first reflective film and the second reflective film. A light-emitting layer is disposed within the resonant cavity, and the light-emitting layer comprises multiple LED units arranged in an array.

2. The light-emitting diode structure according to claim 1, characterized in that, The first reflective film is disposed on the upper surface of the substrate and is located between the substrate and the second reflective film; The peak reflectivity of the first reflective film to the target wavelength is higher than that of the second reflective film to the target wavelength.

3. The light-emitting diode structure according to claim 1, characterized in that, The first reflective film and the second reflective film are both distributed Bragg reflective films.

4. The light-emitting diode structure according to claim 1, characterized in that, The LED unit includes: The LED platform includes a first doped semiconductor layer and an active layer stacked together. A second doped semiconductor layer is stacked on top of the active layer, and at least a portion of the second doped semiconductor layer extends out of the LED mesa.

5. The light-emitting diode structure according to claim 4, characterized in that, The light-emitting layer further includes: A transparent conductive layer is disposed on the outside of the LED platform. The transparent conductive layer is electrically connected to the first doped semiconductor layer of the LED platform, and the transparent conductive layer includes a connection end that extends laterally outward from the LED platform.

6. The light-emitting diode structure according to claim 5, characterized in that, The substrate includes a first contact and a second contact, and the light-emitting layer further includes: A pad is disposed on the side of the LED mesa, and the portion of the second doped semiconductor layer extending out of the LED mesa rests on the pad and is electrically connected to the pad; The first conductive post penetrates the connection end of the transparent conductive layer and is electrically connected to the first contact. The second conductive post penetrates the pad and is electrically connected to the second contact.

7. The light-emitting diode structure according to claim 6, characterized in that, The material of the pad is the same as the material of the transparent conductive layer; The thickness of the pad is the same as the thickness of the connection end of the transparent conductive layer.

8. The light-emitting diode structure according to claim 5, characterized in that, Also includes: A passivation layer is deposited on the surface of the LED unit on the side closest to the substrate and extends between adjacent LED units; A filler layer is provided between adjacent LED units and covers the transparent conductive layer. The first reflective film is disposed on the side of the filler layer away from the LED unit. A planarization layer is disposed above the passivation layer, and a second reflective film is disposed on the top of the planarization layer.

9. A display chip, characterized in that, The display chip includes a light-emitting diode structure as described in any one of claims 1 to 8.

10. An optical communication transmitting light source, characterized in that, The optical communication transmitting light source includes a light-emitting diode structure as described in any one of claims 1 to 8.

11. A method for fabricating a light-emitting diode structure, used to fabricate a light-emitting diode structure as described in any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: Provide substrate; Prepare a light-emitting layer, which includes multiple LED units arranged in an array; A first reflective film is formed on one side of the surface of the light-emitting layer; The first reflective film is disposed above the substrate; A second reflective film is formed above the light-emitting layer, such that the first reflective film and the second reflective film are spaced apart above the substrate, and the light-emitting layer is located in the resonant cavity between the first reflective film and the second reflective film.

12. The preparation method according to claim 11, characterized in that, The steps for preparing the emissive layer include: Prepare a substrate, on one side of which is provided an LED epitaxial layer. The LED epitaxial layer includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked together. The second doped semiconductor layer is disposed on the surface of the substrate. The first doped semiconductor layer and the active layer are etched to form multiple LED mesa arranged in an array. A passivation layer is formed on the surface of the LED mesa and the second doped semiconductor layer. The passivation layer has a first window exposing the first doped semiconductor layer and a second window exposing the second doped semiconductor layer. The second window is located on the side of the LED mesa. A transparent conductive layer and pads are formed. The transparent conductive layer surrounds the outside of the LED mesa and fills the first window to be electrically connected to the first doped semiconductor layer. The transparent conductive layer includes a connection end that extends laterally to the outside of the LED mesa. The pads are filled in the second window and are electrically connected to the second doped semiconductor layer. A filler layer is formed, which fills the spaces between adjacent LED units and covers the transparent conductive layer.

13. The preparation method according to claim 12, characterized in that, The step of forming a first reflective film on one side of the light-emitting layer includes: A first reflective film is formed on the surface of the filler layer on the side away from the substrate.

14. The preparation method according to claim 12, characterized in that, The substrate includes a first contact and a second contact. Before the step of forming a second reflective film above the light-emitting layer, the preparation method further includes: The substrate and a portion of the second doped semiconductor layer are removed to form a plurality of LED units arranged in an array and to expose the surface of a portion of the passivation layer, wherein the second doped semiconductor layer of each LED unit is disposed on the corresponding pad; A planarization layer is formed above the passivation layer; A first via is formed that penetrates at least through the transparent conductive layer at the connection end and a second via is formed that penetrates at least through the pad. The first via exposes the first contact and the second via exposes the second contact. At least a balanced etching rate is achieved through the connection end and the pad. A first conductive post is formed in the first through hole, and a second conductive post is formed in the second through hole.

15. The preparation method according to claim 14, characterized in that, The step of forming a second reflective film above the light-emitting layer includes: A second reflective film is formed on top of the planarization layer.

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