Micro / Nano LED Devices and Their Fabrication Methods

Abstract

This invention discloses a Micro / Nano LED device and its fabrication method. The fabrication method includes: providing a substrate; sequentially forming a buffer layer and an n-type semiconductor layer on the substrate; forming a mask with a through-hole nanopore structure on the n-type semiconductor layer; and forming Micro / Nano LED units within the nanopore structure of the mask. The Micro / Nano LED device and its fabrication method of this invention can fabricate Micro / Nano LED devices over large areas without photolithography or etching, without sidewall damage, and the fabricated Micro / Nano LED devices exhibit excellent luminous performance.

Description

Technical Field

[0001] This invention belongs to the field of LED manufacturing technology, specifically relating to a Micro / Nano LED device and its manufacturing method. Background Technology

[0002] Light-emitting diodes (LEDs) are widely used in lighting and display fields due to their advantages such as high brightness, long lifespan, fast response speed, and environmental friendliness. In recent years, the combination of semiconductor micro-nano manufacturing technology and LED technology has enabled LED display technology to develop rapidly towards micro-displays and high resolution, and micro-LEDs with micrometer-scale feature sizes have received widespread attention internationally.

[0003] Micro-LEDs possess many superior characteristics, such as higher brightness, resolution, and color saturation, lower energy consumption, longer lifespan, and faster response speed, offering broad application prospects. Micro-LED arrays are high-density, micro-sized two-dimensional arrays of LEDs integrated within a small area. Their advantages, such as micro-size and high brightness, enable their application in numerous fields, including high-resolution displays, lensless microscopes, super-resolution microscopes, optical tweezers, optical neural interfaces, maskless lithography, and visible light communication. Meanwhile, with evolving demands, full-color Micro-LED array devices have also come into focus. Full-color display devices have even wider applications, such as panel displays, head-up displays (HUDs), augmented reality (AR), virtual reality (VR), smartwatches, and smartphones.

[0004] Commonly used processes for fabricating Micro-LED devices include ultraviolet lithography and inductively coupled plasma (ICP) etching. These processes result in relatively large LED array structures, typically larger than 1 μm. Furthermore, for smaller LED chips, such as Nano-LEDs, the ratio of ICP-damaged areas to active areas increases, leading to more defects formed during etching and reduced luminous efficiency. Simultaneously, sidewall damage areas pose a risk of leakage, further decreasing chip reliability.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a Micro / Nano LED device and its fabrication method, which can fabricate Micro / Nano LED devices over a large area without photolithography or etching, without sidewall damage, and the fabricated Micro / Nano LED devices have good luminous performance.

[0007] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0008] A method for fabricating a Micro / Nano LED device, comprising:

[0009] Provide substrate;

[0010] A buffer layer and an n-type semiconductor layer are sequentially formed on the substrate;

[0011] A mask plate with a through-hole structure is formed on the n-type semiconductor layer;

[0012] Micro / Nano LED units are formed within the nanopore structure of the mask.

[0013] In one or more embodiments of the present invention, a mask having a through-hole structure of nanopores is formed on the n-type semiconductor layer, comprising:

[0014] Provide substrate;

[0015] A mask plate with a through-hole structure is fabricated on the substrate;

[0016] Remove the substrate and transfer the mask onto the n-type semiconductor layer.

[0017] In one or more embodiments of the present invention, the substrate is made of polymethyl methacrylate, and the mask is an anodized aluminum template;

[0018] Removing the substrate includes:

[0019] The substrate with the mask formed thereon is immersed in an organic solution to dissolve the substrate and obtain the mask.

[0020] The organic solutions include ketone solutions, halohydrocarbon solutions, and aromatic hydrocarbon solutions.

[0021] In one or more embodiments of the present invention, prior to the step of sequentially forming a buffer layer and an n-type semiconductor layer on the substrate, the method further includes:

[0022] The surface of the substrate is cleaned.

[0023] In one or more embodiments of the present invention, the diameter of the nanopore structure on the mask plate ranges from 100 nm to 1 μm.

[0024] In one or more embodiments of the present invention, after the step of forming a mask on the n-type semiconductor layer, the method further includes:

[0025] The mask is bonded to the n-type semiconductor layer by an annealing process.

[0026] In one or more embodiments of the present invention, the height of the Micro / Nano LED unit is greater than the thickness of the mask.

[0027] In one or more embodiments of the present invention, prior to the step of forming Micro / Nano LED units within the nanopore structure of the mask, the method further includes:

[0028] A mask layer is disposed on the surface of the mask plate formed on the n-type semiconductor layer;

[0029] The mask layer is disposed around the side peripheral surface of the mask plate.

[0030] In one or more embodiments of the present invention, after the step of forming Micro / Nano LED units within the nanopore structure, the method further includes:

[0031] A first conductive oxide film is grown on at least the Micro / Nano LED unit;

[0032] Remove the mask layer;

[0033] A second conductive oxide thin film is grown on the n-type semiconductor layer.

[0034] In one or more embodiments of the present invention, the thickness of the second conductive oxide film is less than the thickness of the mask plate.

[0035] A Micro / Nano LED device is fabricated using the aforementioned method for fabricating Micro / Nano LED devices.

[0036] Compared with the prior art, the Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure to grow Micro / Nano LED units over a large area without sidewall damage and with good light-emitting performance.

[0037] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure, which can not only serve as a mask but also as a passivation dielectric layer. This eliminates the need for subsequent photolithography deposition of the passivation dielectric layer, saving time and costs, and simplifying the process flow.

[0038] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure as a passivation dielectric layer, which can directly prepare a conductive oxide thin film (top electrode) without the need to open holes in the passivation dielectric layer, further reducing etching damage.

[0039] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask with a nanopore structure to grow Micro / Nano LED units over a large area. The mask with the nanopore structure can also serve as a passivation dielectric layer after annealing, eliminating the need for subsequent passivation and etching processes.

[0040] The present invention relates to a Micro / Nano LED device and its fabrication method, which utilizes a mask with a nanoporous structure as a mask to grow nanopillars of Micro / Nano LED units. On the one hand, it can fabricate large-area Micro / Nano LED devices while improving the light-emitting performance of the device. On the other hand, after the Micro / Nano LED units are grown, the mask with the nanoporous structure can also serve as a passivation dielectric layer through an annealing process to prevent sidewall leakage of the Micro / Nano LED units. Attached Figure Description

[0041] 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 only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a process flow diagram of a method for fabricating a Micro / Nano LED device according to an embodiment of the present invention; Figures 2a-2g This is a flowchart illustrating the steps of a method for fabricating a Micro / Nano LED device according to an embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0044] As mentioned in the background section, the common process methods for fabricating Micro / Nano-LED devices in the prior art involve ultraviolet lithography and inductively coupled plasma (ICP) etching using photoresist processes. On the one hand, LED array structures fabricated by photolithography and ICP etching are relatively large, typically larger than 1 μm. On the other hand, as LED chip sizes decrease, such as the even smaller size of Nano-LEDs, the proportion of etch-damaged areas to active areas increases due to photolithography and ICP etching, resulting in more defects and reduced luminous efficiency. Simultaneously, sidewall damage areas also pose a risk of leakage, further reducing chip reliability.

[0045] To address the aforementioned technical problems, this invention provides a Micro / Nano LED device and its fabrication method. It employs a large-area mask with a periodic nanopore structure to directly grow nanopillars of Micro / Nano LED units on a substrate. This not only improves the device's luminous performance but also enables the fabrication of large-area Micro / Nano LED devices. Furthermore, after the Micro / Nano LED units are grown, the mask with the nanopore structure can be used as a passivation dielectric layer through an annealing process to prevent sidewall leakage of the Micro / Nano LED units.

[0046] like Figure 1 As shown, the method for fabricating a Micro / Nano LED in one embodiment of the present invention specifically includes the following steps:

[0047] S1 provides a substrate and cleans the surface of the substrate; a buffer layer and an n-type semiconductor layer are sequentially formed on the substrate.

[0048] The substrate can be a silicon substrate or a sapphire substrate. The substrate may include a first surface and a second surface disposed opposite to each other. A buffer layer and an n-type semiconductor layer can be formed on the first surface of the substrate using an MBE device or an MOCVD device.

[0049] S2, a mask with a through-hole structure is formed on an n-type semiconductor layer.

[0050] Specifically, a substrate is first provided, preferably made of polymethyl methacrylate.

[0051] Then, a mask with through-hole nanopores is fabricated on the substrate; the mask is an anodized aluminum template, and the diameter of the nanopores on the mask ranges from 100 nm to 1 μm. Since fabricating a mask with through-hole nanopores on a substrate is a mature process in the prior art, this invention will not elaborate on it in detail.

[0052] Next, the substrate is removed, and the mask is transferred onto the n-type semiconductor layer.

[0053] The substrate removal process specifically includes immersing the substrate with the mask plate in an organic solution to dissolve the substrate and obtain the mask plate. The organic solution can include ketone solutions, halogenated hydrocarbon solutions, and aromatic hydrocarbon solutions. Ketone solutions include methyl ethyl ketone (MEK), cyclohexanone, and acetone. Halogenated hydrocarbon solutions include dichloroethane, trichloroethylene, and chloroform. Aromatic hydrocarbon solutions include toluene, phenol, and anisole.

[0054] In this step, the obtained mask can be surface cleaned and hydrophilicized to enable better contact with the n-type semiconductor layer.

[0055] Finally, an annealing process is used to ensure that the mask is tightly bonded to the n-type semiconductor layer.

[0056] S3, a mask layer is formed on the side peripheral surface of the mask on the n-type semiconductor layer.

[0057] The mask layer is preferably a metal mask. The size of the metal mask is larger than the size of the mask plate and smaller than or equal to the size of the substrate. A through-hole is formed in the center of the metal mask, and the size of the through-hole is approximately equal to the size of the mask plate.

[0058] Specifically, a metal mask is transferred to one side surface of the n-type semiconductor layer where the mask plate is formed, and the metal mask is fitted onto the side peripheral surface of the mask plate.

[0059] S4, forming Micro / Nano LED units within the nanopore structure of the mask.

[0060] Specifically, the substrate with the mask plate containing the nanopore structure is transferred to other growth equipment, such as MOCVD (metal-organic chemical vapor deposition) or MBE (molecular beam epitaxy), through a vacuum pipeline to grow Micro / Nano LED units within the nanopore structure.

[0061] The height of the grown Micro / Nano LED unit is greater than the thickness of the mask.

[0062] S5, a first conductive oxide thin film is grown on the Micro / Nano LED unit, the mask layer, and the mask plate.

[0063] Preferably, the first conductive oxide film is a transparent ITO film.

[0064] S6, remove the mask layer and continue growing a second conductive oxide film on the n-type semiconductor layer.

[0065] Preferably, the second conductive oxide film is also a transparent ITO film. The second conductive oxide film grown on the n-type semiconductor layer can be directly used as the bottom electrode. The first and second conductive oxide films grown on the Micro / Nano LED unit can be used as the top electrode. The thickness of the second conductive oxide film is less than the thickness of the mask to prevent the second conductive oxide film on the n-type semiconductor layer from contacting the first conductive oxide film on the mask.

[0066] Finally, an annealing process is performed again to form a passivation layer around the sidewalls of the Micro / Nano LED unit on the mask, preventing leakage current from the sidewalls of the Micro / Nano LED unit.

[0067] It is understood that the fabrication of the Micro / Nano LED device of the present invention can be carried out in a vacuum interconnection device, preferably in a vacuum environment.

[0068] Figures 2a-2g This is a flowchart illustrating the steps of a method for fabricating a Micro / Nano LED device according to an embodiment of the present invention. The following is in conjunction with... Figures 2a-2g The method for fabricating the Micro / Nano LED device of the present invention will be described in detail to facilitate further understanding of the present invention.

[0069] refer to Figure 2a As shown, a substrate 10 is provided, the substrate 10 having a first surface 10a and a second surface 10b disposed opposite to each other. The first surface 10a of the substrate 10 is cleaned.

[0070] The substrate 10 can be a silicon substrate or a sapphire substrate.

[0071] refer to Figure 2b As shown, a buffer layer 11 and an n-type semiconductor layer 12 are grown on the first surface 10a of the substrate 10. The materials of the buffer layer 11 and the n-type semiconductor layer 12 may include AlGaN, InGaN, etc., and the growth equipment may include MBE or MOCVD equipment.

[0072] refer to Figure 2c As shown, a mask 20 with a through-hole nanopore structure 21 is formed on the surface of an n-type semiconductor layer 12 on the first surface 10a of the substrate 10. The size of the mask 20 is smaller than the size of the substrate 10.

[0073] Specifically, a substrate is first provided, preferably made of polymethyl methacrylate. Then, a mask 20 with through-hole nanopore structures 21 is fabricated on the substrate; the mask 20 is an anodic aluminum oxide template, and the diameter of the nanopore structures 21 on the mask 20 ranges from 100 nm to 1 μm. Since fabricating a mask with through-hole nanopore structures on a substrate is a mature process in the prior art, this invention will not elaborate on it in detail. Next, the substrate is removed, and the mask 20 is transferred to the surface of the n-type semiconductor layer 12 on the first surface 10a of the substrate 10. The substrate removal specifically includes immersing the substrate with the mask 20 in an organic solution to dissolve the substrate and obtain the mask 20. The organic solution may include ketone solutions, halogenated hydrocarbon solutions, and aromatic hydrocarbon solutions. Ketone solutions include methyl ethyl ketone (MEK), cyclohexanone, acetone, etc. Halogenated hydrocarbon solutions include dichloroethane, trichloroethylene, chloroform, etc. Aromatic hydrocarbon solutions include toluene, phenol, anisole, etc. In this step, the obtained mask 20 can be surface-cleaned and hydrophilically treated to enable better contact with the n-type semiconductor layer 12 on the first surface 10a of the substrate 10. Finally, an annealing process is used to ensure that the mask 20 is tightly bonded to the n-type semiconductor layer 12 on the first surface 10a of the substrate 10.

[0074] refer to Figure 2d As shown, a mask layer 30 is formed on the n-type semiconductor layer 12 of the first surface 10a of the substrate 10.

[0075] The mask layer 30 is preferably a metal mask. The size of the metal mask is larger than the size of the mask plate 20 and smaller than or equal to the size of the substrate 10. A through hole is formed in the middle of the metal mask, and the size of the through hole is approximately equal to the size of the mask plate 20.

[0076] A metal mask is transferred onto the n-type semiconductor layer 12 of the first surface 10a of the substrate 10, and the metal mask is disposed on the side peripheral surface of the mask plate 20.

[0077] refer to Figure 2e As shown, Micro / Nano LED units 40 are formed within the nanopore structure 21 of the mask plate 20.

[0078] Specifically, the substrate 10 with the mask 20 containing the nanopore structure 21 is transferred via a vacuum tube to other growth equipment, such as MOCVD (metal-organic chemical vapor deposition) or MBE (molecular beam epitaxy), to grow Micro / Nano LED units 40 within the nanopore structure 21. The height of the grown Micro / Nano LED units 40 is greater than the thickness of the mask 20.

[0079] refer to Figure 2fAs shown, a first conductive oxide thin film 51 is grown on the surface of the Micro / Nano LED unit 40, the mask plate 20, and the mask layer 30.

[0080] refer to Figure 2g As shown, the mask layer 30 is removed, and a second conductive oxide thin film 52 is grown on the n-type semiconductor layer 12 of the first surface 10a of the substrate 10.

[0081] Preferably, both the first conductive oxide film 51 and the second conductive oxide film 52 are transparent ITO films.

[0082] Understandably, during the continued growth of the second conductive oxide film 52, the second conductive oxide film 52 will also continue to accumulate on the first conductive oxide film 51 on the surface of the Micro / Nano LED unit 40 and the mask 20. Therefore, the second conductive oxide film 52 grown on the n-type semiconductor layer 12 of the first surface 10a of the substrate 10 can be directly used as the bottom electrode. The first conductive oxide film 51 and the second conductive oxide film 52 grown on the Micro / Nano LED unit can be used as the top electrode.

[0083] The thickness of the second conductive oxide film 52 is less than the thickness of the mask plate 20, so as to prevent the second conductive oxide film 52 on the n-type semiconductor layer 12 of the first surface 10a of the substrate 10 from contacting the first conductive oxide film 51 on the mask plate 20.

[0084] Finally, an annealing process is performed again to form a passivation layer around the sidewalls of the Micro / Nano LED unit 40 on the mask plate 20, preventing leakage current from the sidewalls of the Micro / Nano LED unit 40.

[0085] The present invention also provides a Micro / Nano LED device, which is manufactured using the above-described method for manufacturing Micro / Nano LED devices.

[0086] Compared with the prior art, the Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure to grow Micro / Nano LED units over a large area without sidewall damage and with good light-emitting performance.

[0087] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure, which can not only serve as a mask but also as a passivation dielectric layer. This eliminates the need for subsequent photolithography deposition of the passivation dielectric layer, saving time and costs, and simplifying the process flow.

[0088] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask plate with a nanopore structure as a passivation dielectric layer, which can directly prepare a conductive oxide thin film (top electrode) without the need to open holes in the passivation dielectric layer, further reducing etching damage.

[0089] The Micro / Nano LED device and its fabrication method of the present invention utilize a mask with a nanopore structure to grow Micro / Nano LED units over a large area. The mask with the nanopore structure can also serve as a passivation dielectric layer after annealing, eliminating the need for subsequent passivation and etching processes.

[0090] The present invention relates to a Micro / Nano LED device and its fabrication method, which utilizes a mask with a nanoporous structure as a mask to grow nanopillars of Micro / Nano LED units. On the one hand, it can fabricate large-area Micro / Nano LED devices while improving the light-emitting performance of the device. On the other hand, after the Micro / Nano LED units are grown, the mask with the nanoporous structure can also serve as a passivation dielectric layer through an annealing process to prevent sidewall leakage of the Micro / Nano LED units.

[0091] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0092] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for fabricating a Micro / Nano LED device, characterized in that, include: Provide substrate; A buffer layer and an n-type semiconductor layer are sequentially formed on the substrate; A mask plate with a through-hole structure is formed on the n-type semiconductor layer; Micro / Nano LED units are formed within the nanopore structure of the mask.

2. The method for fabricating a Micro / Nano LED device according to claim 1, characterized in that, A mask plate having a through-hole structure of nanopores formed on the n-type semiconductor layer includes: Provide substrate; A mask plate with a through-hole structure is fabricated on the substrate; Remove the substrate and transfer the mask onto the n-type semiconductor layer.

3. The method for fabricating a Micro / Nano LED device according to claim 2, characterized in that, The substrate is made of polymethyl methacrylate, and the mask is an anodized aluminum template. Removing the substrate includes: The substrate with the mask formed thereon is immersed in an organic solution to dissolve the substrate and obtain the mask. The organic solutions include ketone solutions, halohydrocarbon solutions, and aromatic hydrocarbon solutions.

4. The method for fabricating a Micro / Nano LED device according to claim 2, characterized in that, Before the step of sequentially forming a buffer layer and an n-type semiconductor layer on the substrate, the method further includes: The surface of the substrate is cleaned.

5. The method for fabricating a Micro / Nano LED device according to claim 1, characterized in that, The diameter of the nanopore structure on the mask plate ranges from 100 nm to 1 μm; and / or, The height of the Micro / Nano LED unit is greater than the thickness of the mask.

6. The method for fabricating a Micro / Nano LED device according to claim 1, characterized in that, After the step of forming a mask on the n-type semiconductor layer, the method further includes: The mask is bonded to the n-type semiconductor layer by an annealing process.

7. The method for fabricating a Micro / Nano LED device according to claim 1, characterized in that, Prior to the step of forming Micro / Nano LED units within the nanopore structure of the mask, the method further includes: A mask layer is disposed on the surface of the n-type semiconductor layer on which the mask plate is formed; The mask layer is disposed around the side peripheral surface of the mask plate.

8. The method for fabricating a Micro / Nano LED device according to claim 7, characterized in that, Following the step of forming Micro / Nano LED units within the nanoporous structure, the method further includes: A first conductive oxide film is grown on at least the Micro / Nano LED unit; Remove the mask layer; A second conductive oxide thin film is grown on the n-type semiconductor layer.

9. The method for fabricating a Micro / Nano LED device according to claim 8, characterized in that, The thickness of the second conductive oxide film is less than the thickness of the mask plate.

10. A Micro / Nano LED device, characterized in that, It is manufactured using the method for manufacturing Micro / Nano LED devices as described in any one of claims 1-9.

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