A deep ultraviolet LED structure

Abstract

The utility model relates to the field of semiconductor technology discloses a kind of deep ultraviolet LED structure, deep ultraviolet LED structure includes: LED base body, LED base body includes sequentially laminated substrate, undoped AlN buffer layer, GaN / AlN superlattice layer, n-type AlGaN layer, active layer, p-type AlGaN layer, p-type GaN cover layer;Multiple nanopores, opening is located p-type GaN cover layer back p-type AlGaN layer side surface, nanopore penetrates p-type GaN cover layer, p-type AlGaN layer and active layer;Isolation layer, located the inner wall of nanopore;Metallic nanoparticles, located p-type GaN cover layer back p-type AlGaN layer side surface, and cover the side surface of isolation layer back nanopore inner wall.The utility model can enhance the LSPR effect between metallic nanoparticles and active layer, improve the intensity and effect of light output, and improve the forward light intensity and effect of deep ultraviolet LED structure.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, specifically to a deep ultraviolet LED structure. Background Technology

[0002] AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) have garnered increasing attention as a highly efficient and portable method for eliminating viruses. Currently, with the increasing Al content in AlGaN materials, the proportion of TM polarized light (transverse magnetic mode) is larger, and the emission mode of DUV LEDs is gradually shifting from TE (transverse electric mode) dominance to TM dominance. High-Al content AlGaN materials exhibit valence band inversion, leading to TM polarization as the dominant emission mode. The light propagation direction is parallel to the material growth axis (c-axis), meaning that laterally propagating TM polarized light primarily propagates laterally, resulting in strong sidewall emission and reduced light output, leading to poor forward light extraction capability. However, traditional flip-chip structures have a vertical light extraction path (e.g., bottom of the device), causing most lateral light to be trapped due to total internal reflection or sidewall absorption, resulting in generally low light extraction efficiency (LEE). Mainstream flip-chip designs rely on vertical light extraction paths (e.g., bottom light extraction from a sapphire substrate), making forward light extraction more compatible with lens packaging and heat dissipation structures, reducing industrialization difficulties. Furthermore, because AlGaN's refractive index is much higher than that of air or the encapsulation material, the critical angle for total internal reflection is very small, and most of the transverse light is reflected back into the material at the vertical interface. Transverse light mainly exits from the device sidewalls, but the sidewall surface area of ​​micron-sized chips is much smaller than the front surface, and geometric constraints result in a narrow light extraction channel.

[0003] Surface plasmon resonance (LSPR) properties are highly beneficial for improving the light output performance of optoelectronic devices. Surface plasmon resonance is a collective oscillation phenomenon that occurs when the frequency of free electrons on the surface of metal nanoparticles matches the frequency of incident photons under incident light radiation of a specific wavelength. Metals capable of generating LSPR are limited to certain alkali and noble metals, such as Al, Au, Ag, and Rh. These metal nanoparticles generate an electromagnetic field near them that can influence the recombination of charge carriers in the active layer, producing a localized surface plasmon resonance (LSPR) effect, which can enhance light output.

[0004] Therefore, a solution is needed that can utilize the LSPR effect of metal nanoparticles to enhance the light output of the device, while converting lateral light into front-facing light, thereby improving the intensity and effect of front-facing light output of the structure. Utility Model Content

[0005] In view of this, the present invention provides a deep ultraviolet LED structure to solve the problem that the light emission mode of the high Al composition AlGaN material deep ultraviolet LED structure in the related technology is mainly TM polarization mode. The lateral propagation of TM polarized light mainly propagates in the lateral direction, resulting in strong sidewall emission, which in turn leads to a reduction in the light output of the device, resulting in poor forward light emission capability, and poor light output and effect of the device.

[0006] This invention provides a deep ultraviolet LED structure, which includes:

[0007] LED substrate, comprising a substrate, an undoped AlN buffer layer, a GaN / AlN superlattice layer, an n-type AlGaN layer, an active layer, a p-type AlGaN layer, and a p-type GaN capping layer stacked sequentially.

[0008] Multiple nanopores are located on the surface of the p-type GaN capping layer facing away from the p-type AlGaN layer. The nanopores penetrate the p-type GaN capping layer, the p-type AlGaN layer and the active layer.

[0009] An isolation layer is located on the inner wall of the nanopore;

[0010] Metal nanoparticles are located on the surface of the p-type GaN capping layer facing away from the p-type AlGaN layer, and cover the surface of the isolation layer facing away from the inner wall of the nanopore.

[0011] The deep ultraviolet LED structure provided by this invention, on the one hand, involves setting nanopores that penetrate the p-type GaN capping layer, the p-type AlGaN layer, and the active layer, and setting an isolation layer and metal nanoparticles on the inner wall of the nanopores. By controlling the thickness of the isolation layer, the metal nanoparticles are brought closer to the active layer, ensuring that the distance between the metal nanoparticles and the active layer meets the conditions for the LSPR effect, thereby maximizing the LSPR effect between the metal nanoparticles and the active layer. This generates an electromagnetic field near the metal nanoparticles that can affect the recombination of charge carriers in the active layer, improving the luminous intensity and light output of the structure. Simultaneously, the nanopores penetrating the active layer can... Increasing the contact area between the metal nanoparticles and the active layer strengthens the excitation of the LSPR effect, further enhancing its enhancement. On the other hand, since the light emission mode of the high-Al composition AlGaN-based deep ultraviolet LED is the TM mode (with more lateral light emission), by covering the side surface of the isolation layer facing away from the inner wall of the nanopore with metal nanoparticles, uneven metal nanoparticle sidewalls can be formed in the nanopores. This allows the main lateral light emission of the deep ultraviolet LED structure to be scattered more into the forward direction of the deep ultraviolet LED structure through the uneven nanoparticle sidewalls, further improving the forward light emission intensity and effect of the structure. Therefore, the deep ultraviolet LED structure provided by this invention can ensure that the distance between the metal nanoparticles and the active layer meets the conditions for the LSPR effect, thereby enhancing the LSPR effect between the metal nanoparticles and the active layer, improving the intensity and effect of light output, and increasing the contact area between the metal nanoparticles and the active layer, further enhancing the LSPR effect. Furthermore, it allows the main lateral light output of the deep ultraviolet LED structure to be more scattered into the forward direction of the deep ultraviolet LED structure through the uneven nanoparticles on the sidewalls, further improving the forward light output intensity and effect of the deep ultraviolet LED structure.

[0012] In one alternative implementation, the nanopores also extend into a portion of the thickness of the n-type AlGaN layer.

[0013] The deep ultraviolet LED structure provided by this invention has nanopores that extend into a portion of the n-type AlGaN layer, which can further increase the contact area between the metal nanoparticles and the active layer, enhance the LSPR effect, and thus improve the luminous intensity and light output of the deep ultraviolet LED structure.

[0014] In one optional embodiment, the resonant wavelength of the metal nanoparticles is 200 nm to 300 nm.

[0015] The emission wavelength of the deep ultraviolet LED structure is 270nm~280nm.

[0016] In one alternative embodiment, the material of the metal nanoparticles is Rh or Al;

[0017] The width of the metal nanoparticles ranges from 10 nm to 150 nm.

[0018] The deep ultraviolet LED structure provided by this invention uses Rh or Al metal nanoparticles with a width of 10nm to 150nm. The resonant wavelength of the metal nanoparticles matches the emission wavelength of the deep ultraviolet LED structure. Since the size of the metal nanoparticles determines the position of the resonance peak, the closer the position of the resonance peak is to the emission wavelength of the deep ultraviolet LED structure, the stronger the LSPR coupling. Therefore, by controlling the width of the metal nanoparticles, the position of the resonance peak of the metal nanoparticles can be made as close as possible to the emission wavelength of the deep ultraviolet LED structure, thereby further enhancing the LSPR effect between the metal nanoparticles and the active layer, and improving the luminous intensity and light output effect of the deep ultraviolet LED structure.

[0019] In one alternative embodiment, the material of the metal nanoparticles 50 is Rh;

[0020] The resonant wavelength of the metal nanoparticles 50 is 270 nm to 290 nm;

[0021] The deep ultraviolet LED structure emits light at a wavelength of 280nm.

[0022] In one alternative implementation, the nanopores are arranged in an array.

[0023] In one optional implementation, the shortest distance between the centerlines of two adjacent nanopores is 200 nm to 700 nm.

[0024] The diameter of the nanopores ranges from 10 nm to 150 nm.

[0025] In one alternative implementation, the substrate material is sapphire;

[0026] The n-type AlGaN layer is made of Si-doped n-type Al 0.6 Ga 0.4 N;

[0027] The active layer has a structure of five-period Al 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 N-quantum well structure;

[0028] In one optional embodiment, the thickness of the undoped AlN buffer layer is 1500 nm to 2500 nm.

[0029] The thickness of the GaN / AlN superlattice layer is 250 nm to 350 nm.

[0030] The thickness of the n-type AlGaN layer is 1300 nm to 1500 nm;

[0031] Al 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 In the N-quantum well structure, the thickness of the well and the barrier in each cycle is 3 nm and 10 nm, respectively;

[0032] The thickness of the p-type AlGaN layer is 30 nm to 50 nm;

[0033] The thickness of the p-type GaN capping layer is 10 nm to 15 nm;

[0034] In one optional embodiment, the material of the isolation layer is SiO2 or Al2O3; the thickness of the isolation layer is 5nm to 15nm.

[0035] The deep ultraviolet LED structure provided by this utility model has an isolation layer thickness of 5nm to 15nm. The isolation layer thickness can be controlled to bring the metal nanoparticles closer to the active layer, so that the distance between the metal nanoparticles and the active layer can meet the conditions for the LSPR effect, thereby maximizing the LSPR effect between the metal nanoparticles and the active layer. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of this utility model, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of a deep ultraviolet LED structure according to an embodiment of the present utility model.

[0038] Figure 2 This is a schematic diagram of light scattering within a nanopore of a deep ultraviolet LED structure according to an embodiment of the present invention.

[0039] Figure 3 This is a schematic flowchart of a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the specific process of a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of the LED substrate structure in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0042] Figure 6 This is a schematic diagram of the dielectric layer formed in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0043] Figure 7 This is a schematic diagram of the ultraviolet imprinting adhesive formed in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0044] Figure 8 This is a schematic diagram of the process of transferring the aperture array pattern to the ultraviolet imprinting adhesive in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0045] Figure 9 This is a schematic diagram of the transfer of the aperture array pattern to the dielectric layer in a method for fabricating a deep ultraviolet LED structure according to an embodiment of the present invention.

[0046] Figure 10 This is a schematic diagram of the nanopores formed in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0047] Figure 11 This is a schematic diagram of the structure forming the isolation layer in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0048] Figure 12 This is a schematic diagram of the metal layer formed in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0049] Figure 13 This is a schematic diagram of the metal nanoparticles formed in a method for preparing a deep ultraviolet LED structure according to an embodiment of the present invention.

[0050] Figure label:

[0051] 11. Substrate; 12. Undoped AlN buffer layer; 13. GaN / AlN superlattice layer; 14. n-type AlGaN layer; 15. Active layer; 16. p-type AlGaN layer; 17. p-type GaN capping layer; 20. Dielectric layer; 30. Nanopore; 40. Isolation layer; 50. Metal nanoparticles; 60. UV imprinting adhesive; 61. PMGI adhesive layer; 62. TU-170 adhesive layer; 70. Metal layer. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0053] In the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of this utility model. Various structural schematic diagrams according to embodiments of this utility model are shown in the accompanying drawings. These drawings are not to scale, and some details are enlarged for clarity, and some details may be omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed. In the context of this utility model, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0054] Deep ultraviolet light, ranging from 200nm to 280nm, can be absorbed by the DNA and RNA of microorganisms, thereby disrupting their DNA / RNA replication through a series of actions, leading to microbial inactivation. Therefore, deep ultraviolet light-emitting diodes (DUV-LEDs) are widely used in disinfection. AlGaN-based DUV-LEDs have attracted increasing attention as a highly efficient and portable method for eliminating viruses. Furthermore, compared to traditional toxic mercury lamps, AlGaN-based DUV-LEDs are safer, more reliable, and have greater development potential. Currently, with the increase in Al content in AlGaN materials, the proportion of TM polarized light is larger, and the light emission mode of deep ultraviolet LEDs is gradually shifting from TE-dominated to TM-dominated. High-Al content AlGaN materials, due to valence band inversion, result in TM polarization as the dominant emission mode. The light propagation direction is parallel to the material growth axis (c-axis), meaning that laterally propagating TM polarized light mainly propagates laterally, leading to strong sidewall emission and consequently reducing the light output of the device, resulting in poor forward light emission capability. However, the traditional flip-chip structure's light extraction path is designed vertically (e.g., at the bottom of the device), causing most lateral light to be trapped due to total internal reflection or sidewall absorption, resulting in generally low light extraction efficiency (LEE). Mainstream flip-chip designs rely on vertical light extraction paths (e.g., bottom light emission from a sapphire substrate), and forward light emission is more compatible with lens packaging and heat dissipation structures, reducing industrialization difficulties. Furthermore, because AlGaN's refractive index is much higher than air or packaging materials, the critical angle for total internal reflection is very small, meaning most lateral light is reflected back into the material at the vertical interface. Lateral light mainly exits from the device sidewalls, but the sidewall surface area of ​​micron-sized chips is much smaller than the front surface, geometrically limiting the narrow light extraction channel.

[0055] Surface plasmon resonance (SPR) properties are highly beneficial for improving the light extraction performance of optoelectronic devices. SPR is a collective oscillation phenomenon that occurs when the frequency of free electrons on the surface of metal nanoparticles matches the frequency of incident photons under incident light radiation of a specific wavelength. Metals capable of generating SPR are limited to certain alkali and noble metals, such as Al, Au, Ag, and Rh. These metal nanoparticles generate an electromagnetic field near them that can influence the recombination of charge carriers in the active layer, thereby enhancing light output.

[0056] Therefore, a solution is needed that can utilize the LSPR effect of metal nanoparticles to enhance the light output of the device, while converting lateral light into front-facing light, thereby improving the intensity and effect of front-facing light output of the structure.

[0057] like Figure 1 As shown, this embodiment provides a deep ultraviolet LED structure, which includes:

[0058] LED substrate, comprising a substrate 11, an undoped AlN buffer layer 12, a GaN / AlN superlattice layer 13, an n-type AlGaN layer 14, an active layer 15, a p-type AlGaN layer 16, and a p-type GaN capping layer 17 stacked sequentially.

[0059] Multiple nanopores 30 have openings located on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The nanopores 30 penetrate the p-type GaN capping layer 17, the p-type AlGaN layer 16 and the active layer 15.

[0060] An isolation layer 40 is located on the inner wall of the nanopore 30;

[0061] Metal nanoparticles 50 are located on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16, and cover the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30.

[0062] In practical implementation, when the metal nanoparticles 50 are sufficiently close to the active layer 15, the metal nanoparticles 50 can act as surface plasmons. When the absorption wavelength of the metal nanoparticles 50 matches the emission wavelength of the active layer 15, an LSPR effect occurs between the metal nanoparticles 50 and the active layer 15, generating electromagnetic waves that couple with the active layer 15. The coupling mechanism involves generating an electromagnetic field near the metal nanoparticles 50. The presence of this electromagnetic field increases the recombination of electron-hole pairs in the active layer 15, thereby increasing the internal quantum efficiency (IQE) of the device and enhancing its luminescence intensity. Furthermore, as... Figure 2As shown, metal nanoparticles 50 cover the side surface of the isolation layer 40 facing away from the inner wall of the nanopore, which can form uneven metal nanoparticle sidewalls in the nanopore 30. This allows the main lateral light output of the deep ultraviolet LED structure to be scattered more into the forward direction of the deep ultraviolet LED structure through the uneven nanoparticle sidewalls, further improving the forward light output intensity and effect of the structure.

[0063] The deep ultraviolet LED structure provided in this embodiment, on the one hand, involves setting nanopores that penetrate the p-type GaN capping layer, the p-type AlGaN layer, and the active layer, and setting an isolation layer and metal nanoparticles on the inner wall of the nanopores. By controlling the thickness of the isolation layer, the metal nanoparticles are brought closer to the active layer, ensuring that the distance between the metal nanoparticles and the active layer meets the conditions for the LSPR effect, thereby maximizing the LSPR effect between the metal nanoparticles and the active layer. This generates an electromagnetic field near the metal nanoparticles that can affect the recombination of charge carriers in the active layer, improving the luminous intensity and light output of the structure. Simultaneously, the nanopores penetrating the active layer can... Increasing the contact area between the metal nanoparticles and the active layer strengthens the excitation of the LSPR effect, further enhancing its enhancement. On the other hand, since the light emission mode of the high-Al composition AlGaN-based deep ultraviolet LED is the TM mode (with more lateral light emission), by covering the side surface of the isolation layer facing away from the inner wall of the nanopore with metal nanoparticles, uneven metal nanoparticle sidewalls can be formed in the nanopores. This allows the main lateral light emission of the deep ultraviolet LED structure to be scattered more into the forward direction of the deep ultraviolet LED structure through the uneven nanoparticle sidewalls, further improving the forward light emission intensity and effect of the structure. Therefore, the deep ultraviolet LED structure provided by this invention can ensure that the distance between the metal nanoparticles and the active layer meets the conditions for the LSPR effect, thereby enhancing the LSPR effect between the metal nanoparticles and the active layer, improving the light output intensity and effect. At the same time, it can increase the contact area between the metal nanoparticles and the active layer, further enhancing the LSPR effect. Furthermore, it can enable more of the main lateral light emitted by the deep ultraviolet LED structure to be scattered into the forward direction of the deep ultraviolet LED structure through the uneven nanoparticles on the sidewalls, further improving the forward light emission intensity and effect of the deep ultraviolet LED structure.

[0064] In some alternative embodiments, the nanopores 30 also extend into a portion of the thickness of the n-type AlGaN layer 14.

[0065] The deep ultraviolet LED structure provided in this embodiment has nanopores that extend into a portion of the n-type AlGaN layer, which can further increase the contact area between the metal nanoparticles and the active layer, enhance the LSPR effect, and thus improve the luminous intensity and light output of the deep ultraviolet LED structure.

[0066] In some alternative embodiments, the material of the metal nanoparticles 50 is Rh or Al;

[0067] The width of the metal nanoparticles 50 is 10 nm to 150 nm;

[0068] The resonant wavelength of the metal nanoparticles 50 is 200 nm to 300 nm;

[0069] The emission wavelength of the deep ultraviolet LED structure is 270nm~280nm.

[0070] In practical implementation, the emission wavelength of the deep ultraviolet LED structure is the same as the emission wavelength of the active layer. The resonant wavelength of the metal nanoparticles 50 matches the emission wavelength of the active layer, which can produce the LSPR effect.

[0071] The deep ultraviolet LED structure provided in this embodiment uses Rh or Al metal nanoparticles with a width of 10nm to 150nm. The resonant wavelength of the metal nanoparticles matches the emission wavelength of the deep ultraviolet LED structure. Since the size of the metal nanoparticles determines the position of the resonance peak, the closer the position of the resonance peak is to the emission wavelength of the deep ultraviolet LED structure, the stronger the LSPR coupling. Therefore, by controlling the width of the metal nanoparticles, the position of the resonance peak of the metal nanoparticles can be made as close as possible to the emission wavelength of the deep ultraviolet LED structure, thereby further enhancing the LSPR effect between the metal nanoparticles and the active layer, and improving the luminous intensity and light output effect of the deep ultraviolet LED structure.

[0072] In some alternative embodiments, the material of the metal nanoparticles 50 is Rh;

[0073] The width of the metal nanoparticles 50 is 10 nm to 150 nm;

[0074] The resonant wavelength of the metal nanoparticles 50 is 270 nm to 290 nm;

[0075] The deep ultraviolet LED structure emits light at a wavelength of 280nm.

[0076] In some alternative implementations, the nanopores 30 are arranged in an array;

[0077] The shortest distance between the center lines of two adjacent nanopores 30 is 200 nm to 700 nm;

[0078] The diameter of the nanopore 30 is 10 nm to 150 nm.

[0079] Among them, the array of nanopores 30 contains multiple periods, and the period of the nanopores 30 ranges from 200nm to 700nm, that is, the shortest distance between the center lines of two adjacent nanopores 30 is 200nm to 700nm.

[0080] In some alternative embodiments, the substrate 11 is made of sapphire.

[0081] The thickness of the undoped AlN buffer layer 12 is 1500 nm to 2500 nm;

[0082] The thickness of GaN / AlN superlattice layer 13 is 250 nm to 350 nm;

[0083] The n-type AlGaN layer 14 is made of Si-doped n-type Al. 0.6 Ga 0.4 The thickness of the N;n-type AlGaN layer 14 is 1300nm~1500nm;

[0084] The active layer 15 has a structure of five-period Al. 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 N-quantum well structure; the thickness of the well and the barrier in each period are 3 nm and 10 nm, respectively;

[0085] The thickness of the p-type AlGaN layer 16 is 30nm to 50nm;

[0086] The thickness of the p-type GaN capping layer 17 is 10 nm to 15 nm;

[0087] The material of the isolation layer 40 is SiO2 or Al2O3; the thickness of the isolation layer 40 is 5nm to 15nm.

[0088] The deep ultraviolet LED structure provided in this embodiment has an isolation layer thickness of 5nm to 15nm. The isolation layer thickness can be controlled to bring the metal nanoparticles closer to the active layer, so that the distance between the metal nanoparticles and the active layer can meet the conditions for the LSPR effect, thereby maximizing the LSPR effect between the metal nanoparticles and the active layer.

[0089] Figure 3 This is a schematic flowchart of a method for fabricating the above-mentioned deep ultraviolet LED structure, which includes, but is not limited to, steps S101 to S105.

[0090] Step S101: Provide an LED substrate, which includes a substrate 11, an undoped AlN buffer layer 12, a GaN / AlN superlattice layer 13, an n-type AlGaN layer 14, an active layer 15, a p-type AlGaN layer 16, and a p-type GaN capping layer 17, stacked sequentially. Figure 5 As shown;

[0091] Step S102: A dielectric layer 20 is formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16, such as... Figure 6 As shown;

[0092] In step S103, multiple nanopores 30 are formed on the surface of the dielectric layer 20 facing away from the p-type GaN capping layer 17. The nanopores 30 penetrate the dielectric layer 20, the p-type GaN capping layer 17, the p-type AlGaN layer 16, and the active layer 15, such as... Figure 10 As shown; then remove the dielectric layer 20, as... Figure 11 As shown;

[0093] Step S104: An isolation layer 40 is formed on the inner wall of the nanopore 30, such as... Figure 12 As shown;

[0094] Step S105: Metal nanoparticles 50 are formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The metal nanoparticles 50 also cover the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30, such as... Figure 12 As shown.

[0095] The fabrication method of this deep ultraviolet LED structure involves, on the one hand, forming nanopores that penetrate the dielectric layer, p-type GaN capping layer, p-type AlGaN layer, and active layer, and then removing the dielectric layer. The dielectric layer protects the LED structure from damage during the nanopore formation process. Next, an isolation layer and metal nanoparticles are formed on the inner wall of the nanopores. By controlling the thickness of the isolation layer, the metal nanoparticles are brought closer to the active layer, ensuring that the distance between the metal nanoparticles and the active layer meets the conditions for the LSPR effect. This maximizes the LSPR effect between the metal nanoparticles and the active layer. An electromagnetic field is generated near the particles that can affect the recombination of charge carriers in the active layer, thereby improving the luminous intensity and light output of the structure. At the same time, the nanopores penetrating the active layer can increase the contact area between the metal nanoparticles and the active layer, thus strengthening the excitation of the LSPR effect and further enhancing the LSPR effect. On the other hand, the uneven metal nanoparticle sidewalls formed in the nanopores allow more of the main lateral light emitted by the deep ultraviolet LED structure to be scattered into the forward direction of the deep ultraviolet LED structure through the uneven sidewalls of the nanoparticles, further improving the forward light emission intensity and effect of the structure.

[0096] In some alternative implementations, the nanopores also extend into a portion of the thickness of the n-type AlGaN layer.

[0097] In some alternative embodiments, the step of forming the metal nanoparticles 50 includes:

[0098] A metal layer 70 is formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The metal layer 70 also covers the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30.

[0099] The metal layer 70 is subjected to a thermal annealing process to form metal nanoparticles 50. The metal nanoparticles 50 are located on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16, and cover the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30.

[0100] The method for fabricating this deep ultraviolet LED structure involves forming a metal layer inside the nanopore and then using a thermal annealing process to form metal nanoparticles attached to the pore walls. This eliminates the need for additional methods to fabricate the metal nanoparticles, making the process simpler and more efficient, thus improving process efficiency and reducing process costs.

[0101] In some alternative embodiments, the thickness of the metal layer 70 is 2 nm to 10 nm;

[0102] The temperature for hot annealing is 600℃~900℃;

[0103] The width of the metal nanoparticles 50 ranges from 10 nm to 150 nm.

[0104] The fabrication method of this deep ultraviolet LED structure, by controlling the thickness of the metal layer to 2nm to 10nm and the temperature of the thermal annealing process to 600℃ to 900℃, can control the width of the metal nanoparticles to 10nm to 150nm, so that the resonance peak position of the metal nanoparticles is as close as possible to the emission wavelength of the deep ultraviolet LED structure, thereby further enhancing the LSPR effect between the metal nanoparticles and the active layer, and improving the luminous intensity and light output effect of the deep ultraviolet LED structure.

[0105] In some alternative implementations, the nanopores 30 are arranged in an array;

[0106] The steps for forming multiple nanopores 30 include:

[0107] IPS soft templates are provided; IPS soft templates include hole array patterns;

[0108] A UV imprinting adhesive 60 is formed on the surface of the dielectric layer 20 on the side opposite to the p-type GaN capping layer 17. The UV imprinting adhesive 60 includes a stacked PMGI adhesive layer 61 and a TU-170 adhesive layer 62.

[0109] UV soft imprinting is performed on UV imprinting adhesive 60 using an IPS soft template. After UV exposure, the UV imprinting adhesive 60 is fully cured, and then the IPS soft template is removed.

[0110] Remove the residual UV imprinting adhesive 60 and transfer the hole array pattern onto the UV imprinting adhesive 60 to obtain patterned UV imprinting adhesive;

[0111] Using patterned UV imprinting adhesive as a mask, the dielectric layer 20 is etched to transfer the hole array pattern onto the dielectric layer 20, forming a patterned dielectric layer;

[0112] Using a patterned dielectric layer as a mask, a p-type GaN capping layer 17, a p-type AlGaN layer 16, and an active layer 15 are etched to form multiple arrayed nanopores 30.

[0113] The dielectric layer was then removed using an HF solution.

[0114] The resulting array of nanopores 30 penetrates the p-type GaN capping layer, the p-type AlGaN layer, and the active layer.

[0115] The fabrication method of this deep ultraviolet LED structure first forms a patterned dielectric layer using nanoimprint lithography, and then uses this patterned dielectric layer as a mask to form multiple arrayed nanopores. Compared with traditional etching processes, nanoimprint lithography has the following advantages: First, nanoimprint lithography offers higher resolution: it can achieve smaller structure sizes than traditional photolithography, even reaching sub-nanometer resolution. The resolution of conventional photolithography is usually limited by the wavelength of the light source, while nanoimprint lithography uses a mold to form nanoscale structures, thus overcoming this limitation. Second, nanoimprint lithography has lower costs: the molds used in nanoimprint lithography can be reused through a simple imprinting process, significantly reducing manufacturing costs compared to the mask fabrication, exposure, and development steps in photolithography. Furthermore, nanoimprint lithography does not rely on expensive laser sources and complex mask manufacturing processes. Third, nanoimprint lithography does not require a high-precision alignment system: in some photolithography processes, accurate alignment is crucial for multi-layered pattern transfer, while nanoimprint lithography typically does not rely on an alignment system, directly transferring the pattern to the material surface through the imprinting mold, simplifying equipment and processes.

[0116] In some alternative embodiments, the step of forming an isolation layer 40 on the inner wall of the nanopore 30 includes:

[0117] An isolation layer 40 is formed on the surface of the p-type GaN capping layer 17 on the side opposite to the p-type AlGaN layer 16, and the isolation layer 40 also covers the inner wall of the nanopore 30.

[0118] The isolation layer 40 on the surface of the p-type GaN capping layer 17 is removed by a dry etching process, leaving only the isolation layer 40 on the inner wall of the nanopore 30.

[0119] In some alternative embodiments, the substrate 11 is made of sapphire.

[0120] The thickness of the undoped AlN buffer layer 12 is 1500 nm to 2500 nm;

[0121] The thickness of GaN / AlN superlattice layer 13 is 250 nm to 350 nm;

[0122] The n-type AlGaN layer 14 is made of Si-doped n-type Al. 0.6 Ga 0.4 The thickness of the N;n-type AlGaN layer 14 is 1300nm~1500nm;

[0123] The active layer 15 has a structure of five-period Al. 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 N-quantum well structure; the thickness of the well and the barrier in each period are 3 nm and 10 nm, respectively;

[0124] The thickness of the p-type AlGaN layer 16 is 30nm to 50nm;

[0125] The thickness of the p-type GaN capping layer 17 is 10 nm to 15 nm;

[0126] The dielectric layer 20 is made of SiO2; the thickness of the dielectric layer 20 is 100nm to 300nm.

[0127] The material of the isolation layer 40 is SiO2 or Al2O3; the thickness of the isolation layer 40 is 5nm to 15nm.

[0128] Figure 4 This is a schematic diagram of a specific process for fabricating the above-mentioned deep ultraviolet LED structure, including the following steps:

[0129] Step S201: Provide an LED substrate, which includes a substrate 11, an undoped AlN buffer layer 12, a GaN / AlN superlattice layer 13, an n-type AlGaN layer 14, an active layer 15, a p-type AlGaN layer 16, and a p-type GaN capping layer 17 stacked sequentially.

[0130] In one example, such as Figure 5 As shown, the LED substrate is fabricated by: epitaxially growing a 2000 nm thick undoped AlN buffer layer on a sapphire substrate 11; growing a 300 nm thick GaN / AlN superlattice layer 13 on the undoped AlN buffer layer; and growing a 1400 nm thick Si-doped n-type AlN superlattice layer on top of the GaN / AlN superlattice layer 13. 0.6 Ga 0.4 N-layer; five cycles of Al are grown above the n-type AlGaN layer 14. 0.37 Ga 0.63 N / Al 0.47 Ga 0.53The N-quantum well structure has a well width of 3 nm and a barrier width of 10 nm. A p-type AlGaN layer 16 with a thickness of 30 nm to 50 nm is grown on top of the quantum well structure (i.e., the active layer 15). A p-GaN capping layer with a thickness of 10 nm to 15 nm is grown on top of the p-type AlGaN layer 16.

[0131] Step S202: A dielectric layer 20 is formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16.

[0132] In one example, such as Figure 6 As shown, a 200 nm thick SiO2 layer is grown on the side of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16 using a PECVD process.

[0133] Step S203: Provide an IPS soft stencil; the IPS soft stencil includes a hole array pattern; form a UV imprinting adhesive 60 on the surface of the dielectric layer 20 facing away from the p-type GaN capping layer 17, the UV imprinting adhesive 60 including a stacked PMGI adhesive layer 61 and a TU-170 adhesive layer 62, such as... Figure 7 As shown; UV soft imprinting is performed on UV imprinting adhesive 60 using an IPS soft template. After UV exposure, the UV imprinting adhesive 60 is fully cured, and the IPS soft template is removed; the remaining UV imprinting adhesive 60 is removed, and the hole array pattern is transferred onto the UV imprinting adhesive 60, as shown. Figure 8 As shown, a patterned UV imprinting adhesive is obtained.

[0134] In specific implementation, the steps for providing the IPS soft template include: using a raw Ni metal template to thermally imprint the IPS composite softened plate; when selecting the Ni metal template, the size of the periodic nanopores 30 in the hole array pattern is controlled by analyzing the period and duty cycle. The steps for forming the UV imprinting adhesive 60 include: using a spin coater to sequentially spin-coat a 70nm thick layer of PMGI adhesive and a 200nm thick layer of TU-170 UV imprinting adhesive 60 onto the surface and baking it, the purpose being to maximize the proportion of the exposed sidewall area of ​​the active layer 15. Finally, the sample is UV soft-imprinted using the IPS soft template. After UV exposure, the UV imprinting adhesive 60 is fully cured, and the IPS soft template is peeled off, leaving the hole array on the UV imprinting adhesive 60. The pattern is transferred using reactive ion etching (RIE) technology. First, oxygen plasma is used to remove residual TU-170 adhesive, then positive photoresist developer is used to remove PMGI adhesive, transferring the hole array pattern onto the UV imprinting adhesive 60.

[0135] Step S204: Using patterned UV imprinting adhesive as a mask, the dielectric layer 20 is etched to transfer the hole array pattern onto the dielectric layer 20, such as... Figure 9 As shown, a graphical media layer is formed.

[0136] In practice, the dielectric layer 20 is made of silicon dioxide. A patterned UV imprinting adhesive is used as a mask, and CHF3 gas is used for ICP etching of the silicon dioxide dielectric layer 20. The hole array pattern is transferred from the imprinting adhesive to the silicon dioxide dielectric layer 20. Subsequently, TU-170 and PMGI adhesives are completely removed by ultrasonication for 3 minutes each with acetone, alcohol, and deionized water. Etching parameters: CHF3 flow rate 20 sccm, Ar flow rate 5 sccm, RF power 40 W, ICP power 230 W.

[0137] In step S205, using the patterned dielectric layer as a mask, the p-type GaN capping layer 17, the p-type AlGaN layer 16, and the active layer 15 are etched to form multiple arrayed nanopores 30, such as... Figure 10 As shown.

[0138] In practice, a patterned silicon dioxide dielectric layer 20 is used as a mask layer. Cl2 / BCl3 gas is used to etch the p-type GaN capping layer 17, the p-type AlGaN layer 16, and the active layer 15, forming multiple nanopores 30. These nanopores 30 penetrate the dielectric layer 20, the p-type GaN capping layer 17, the p-type AlGaN layer 16, and the active layer 15, transferring the pattern below the quantum well layer. The etching depth can be controlled by adjusting the etching time in this step. Etching parameters: Cl2 flow rate 18 sccm, BCl3 flow rate 25 sccm, RF power 25 W, ICP power 750 W. By etching below the active layer 15, the isolation layer 40 and the metal layer can be deposited onto the sidewalls of the active layer 15, thereby increasing the contact area between the metal nanoparticles 50 and the active layer 15 after annealing, thus enhancing the LSPR effect to a greater extent.

[0139] In one example, during the step of forming the nanopore 30, a portion of the thickness of the n-type AlGaN layer 14 is also etched, such that the formed nanopore 30 extends into the portion of the thickness of the n-type AlGaN layer 14.

[0140] Step S206: The dielectric layer 20 is removed using an HF solution, forming multiple arrayed nanopores 30 that penetrate the p-type GaN capping layer 17, the p-type AlGaN layer 16, and the active layer 15, as shown below. Figure 11 As shown.

[0141] In practice, a 40% HF solution is used to remove the silica dielectric layer 20.

[0142] In one example, the nanopores 30, after the dielectric layer is removed, extend into a portion of the n-type AlGaN layer 14, such as... Figure 11 As shown.

[0143] Step S207: An isolation layer 40 is formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The isolation layer 40 also covers the inner wall of the nanopore 30, such as... Figure 11 As shown.

[0144] In specific implementation, an isolation layer 40 is grown using PECVD process. The material of the isolation layer 40 is SiO2 or Al2O3, and the thickness of the isolation layer 40 is 5nm to 15nm.

[0145] Step S208: The isolation layer 40 on the surface of the p-type GaN capping layer 17 is removed using a dry etching process, leaving only the isolation layer 40 on the inner wall of the nanopore 30. Figure 12 As shown.

[0146] In practice, the top isolation layer 40 and the isolation layer 40 on the surface of the p-type GaN capping layer 17 are etched away using the ICP dry etching process, leaving only the isolation layer 40 on the inner wall of the nanopore 30.

[0147] Step S209: A metal layer 70 is formed on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The metal layer 70 also covers the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30, such as... Figure 12 As shown.

[0148] In practice, an electron beam evaporator is used to deposit a metal layer of a certain thickness on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16. The metal layer 70 also covers the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30. In one example, the material of the metal layer 70 is Rh, and the thickness of the metal layer 70 is 2 nm to 10 nm. The thickness of the metal layer determines the size of the metal nanoparticles 50 formed after annealing, and the size of the metal nanoparticles 50 determines the position of the resonance peak. The closer the position of the resonance peak is to the emission wavelength of the final deep ultraviolet LED structure, the stronger the LSPR coupling.

[0149] Step S210: The metal layer 70 is subjected to a thermal annealing process to form metal nanoparticles 50. The metal nanoparticles 50 are located on the surface of the p-type GaN capping layer 17 facing away from the p-type AlGaN layer 16, and cover the surface of the isolation layer 40 facing away from the inner wall of the nanopore 30, as shown below. Figure 13 As shown.

[0150] In one example, the material of the metal layer 70 is Rh, and the thickness of the metal layer 70 is 2nm to 10nm; the temperature of the thermal annealing process is 600℃ to 900℃; the width of the metal nanoparticles 50 formed after annealing is 10nm to 150nm. The resonant wavelength of the metal nanoparticles 50 is 270nm to 290nm; the emission wavelength of the deep ultraviolet LED structure is 280nm.

[0151] In the description of this specification, the terms "this embodiment," "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0152] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0153] The above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention. The protection scope of the present invention is determined by the scope of the appended claims.

Claims

1. A deep ultraviolet LED structure, characterized in that, include: LED substrate, the LED substrate comprising a substrate, an undoped AlN buffer layer, a GaN / AlN superlattice layer, an n-type AlGaN layer, an active layer, a p-type AlGaN layer, and a p-type GaN capping layer stacked sequentially; Multiple nanopores have openings located on the surface of the p-type GaN capping layer facing away from the p-type AlGaN layer, and the nanopores penetrate the p-type GaN capping layer, the p-type AlGaN layer, and the active layer; An isolation layer is located on the inner wall of the nanopore; Metal nanoparticles are located on the surface of the p-type GaN capping layer facing away from the p-type AlGaN layer, and cover the surface of the isolation layer facing away from the inner wall of the nanopore.

2. The deep ultraviolet LED structure according to claim 1, characterized in that, The nanopores also extend into a portion of the thickness of the n-type AlGaN layer.

3. The deep ultraviolet LED structure according to claim 1, characterized in that, The resonant wavelength of the metal nanoparticles is 200 nm to 300 nm; The deep ultraviolet LED structure emits light at a wavelength of 270nm to 280nm.

4. The deep ultraviolet LED structure according to claim 3, characterized in that, The material of the metal nanoparticles is Rh or Al; The width of the metal nanoparticles is 10 nm to 150 nm.

5. The deep ultraviolet LED structure according to claim 4, characterized in that, The material of the metal nanoparticles is Rh; The resonant wavelength of the metal nanoparticles is 270 nm to 290 nm; The deep ultraviolet LED structure emits light at a wavelength of 280 nm.

6. The deep ultraviolet LED structure according to claim 1, characterized in that, The nanopores are arranged in an array.

7. The deep ultraviolet LED structure according to claim 6, characterized in that, The shortest distance between the centerlines of two adjacent nanopores is 200 nm to 700 nm; The diameter of the nanopore is 10 nm to 150 nm.

8. The deep ultraviolet LED structure according to claim 1, characterized in that, The substrate is made of sapphire. The material of the n-type AlGaN layer is Si-doped n-type Al. 0.6 Ga 0.4 N; The active layer has a structure of five-period Al. 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 N-quantum well structure.

9. The deep ultraviolet LED structure according to claim 8, characterized in that, The thickness of the undoped AlN buffer layer is 1500 nm to 2500 nm; The thickness of the GaN / AlN superlattice layer is 250 nm to 350 nm. The thickness of the n-type AlGaN layer is 1300 nm to 1500 nm; The Al 0.37 Ga 0.63 N / Al 0.47 Ga 0.53 In the N-quantum well structure, the thickness of the well and the barrier in each cycle is 3 nm and 10 nm, respectively; The thickness of the p-type AlGaN layer is 30 nm to 50 nm; The thickness of the p-type GaN capping layer is 10 nm to 15 nm.

10. The deep ultraviolet LED structure according to claim 1, characterized in that, The material of the isolation layer is SiO2 or Al2O3; the thickness of the isolation layer is 5nm to 15nm.

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