A deep ultraviolet light emitting diode

Abstract

This invention provides a deep ultraviolet light-emitting diode (DUV), comprising a substrate, an intrinsic layer, an N-type semiconductor layer, a quantum well active layer, an electron blocking layer, and a P-type semiconductor layer stacked from bottom to top. The surface of the quantum well active layer away from the N-type semiconductor layer is a first surface, and a plurality of first microstructures are disposed on the first surface, each first microstructure being recessed within the first surface. By disposing of multiple first microstructures on the first surface of the quantum well active layer away from the N-type semiconductor layer, and by having the first microstructures recessed within the first surface, this invention releases the accumulated stress of the quantum well active layer during its formation, reducing the piezoelectric polarization intensity within the quantum well material, thereby increasing the wavefunction overlap rate and ultimately improving the luminous efficiency of the deep ultraviolet light-emitting diode.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronics, and more particularly to a deep ultraviolet light-emitting diode. Background Technology

[0002] In deep ultraviolet (DUV) light-emitting diodes (LEDs), AlGaN is a direct wide-bandgap semiconductor material. Its bandgap width can be continuously adjusted by changing the amount of Al doping (from GaN with a bandgap of 3.4 eV to AlN with a bandgap of 6.2 eV), achieving light emission in the spectral range of 365 nm to 200 nm. It also possesses excellent properties such as stable physicochemical properties, high temperature resistance, and radiation resistance, making it the best candidate material for fabricating semiconductor DUV light source devices. Furthermore, AlGaN-based DUVs offer numerous advantages over traditional mercury lamps, including smaller size, lower power consumption, environmental friendliness, safety, and higher integration, and are expected to achieve breakthroughs and widespread applications in the coming years, attracting increasing attention and importance in recent years.

[0003] However, the luminous efficiency of deep ultraviolet (LEX) LEDs based on AlGaN materials remains relatively low. This is because AlGaN has a wurtzite structure, which exhibits spontaneous polarization and piezoelectric polarization along the c-direction perpendicular lattice. This polarization generates a large polarization electric field within the material. The electric field generated by polarization causes the wave functions of electrons and holes to separate, reducing the wave function overlap ratio and thus lowering the luminous efficiency of the LEX LED. Specifically, the piezoelectric polarization of AlGaN is related to the internal stress of the thin film. When the material is subjected to stress, the c / a ratio (the ratio of the perpendicular lattice constant to the basal lattice constant) changes, thereby affecting the polarization intensity within the material.

[0004] Therefore, there is an urgent need for a deep ultraviolet light-emitting diode to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a deep ultraviolet light-emitting diode (LED) to improve the technical problem of low luminous efficiency of the quantum well active layer in existing deep ultraviolet LED diodes.

[0006] To solve the above-mentioned technical problems, the present invention provides a deep ultraviolet light-emitting diode, comprising a substrate, an intrinsic layer, an N-type semiconductor layer, a quantum well active layer, an electron blocking layer, and a P-type semiconductor layer stacked from bottom to top;

[0007] The surface of the quantum well active layer away from the N-type semiconductor layer is the first surface, and a plurality of first microstructures are disposed on the first surface, each of which is recessed into the first surface.

[0008] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the first microstructure is fabricated by a first process, which includes any one of photolithography, electron beam lithography, and plasma etching.

[0009] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the width of the first microstructure ranges from 1 nm to 100 nm, and the depth of the first microstructure ranges from 1 nm to 200 nm.

[0010] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the cross-sectional shape of the first microstructure includes any one of arc shape, square shape and hexagonal shape.

[0011] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, a plurality of first microstructures are arranged adjacently or spaced apart.

[0012] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the quantum well active layer is a periodically arranged AlGaN multilayer periodic structure, and each periodic structure includes a barrier layer and a potential well layer.

[0013] The active quantum well layer has a period number greater than 1 and less than 10; the barrier layer has a thickness ranging from 1 nm to 15 nm, and the mass percentage of aluminum in the barrier layer ranges from 30% to 90%; the well layer has a thickness ranging from 0.5 nm to 10 nm, and the mass percentage of aluminum in the well layer ranges from 20% to 70%.

[0014] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the side surface of the electron blocking layer near the quantum well active layer is a second surface, and a plurality of second microstructures are disposed on the second surface, each of the second microstructures being recessed in the second surface.

[0015] Each second microstructure is positioned opposite each first microstructure.

[0016] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the width of each second microstructure decreases linearly from the side closer to the quantum well active layer to the side farther away from the quantum well active layer.

[0017] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the height of the second microstructure ranges from 3 nm to 180 nm.

[0018] In the deep ultraviolet light-emitting diode provided in the embodiments of the present invention, the electron blocking layer is made of P-type doped AlGaN, the mass percentage of aluminum component in the electron blocking layer ranges from 50% to 90%, and the thickness of the electron blocking layer ranges from 5 nm to 200 nm.

[0019] The beneficial effects of this invention are as follows: Unlike the prior art, this invention provides a deep ultraviolet light-emitting diode, comprising a substrate, an intrinsic layer, an N-type semiconductor layer, a quantum well active layer, an electron blocking layer, and a P-type semiconductor layer stacked from bottom to top. The surface of the quantum well active layer away from the N-type semiconductor layer is a first surface, and a plurality of first microstructures are disposed on the first surface, each first microstructure being recessed within the first surface. By disposing of a plurality of first microstructures on the first surface of the quantum well active layer away from the N-type semiconductor layer, and by having the first microstructures recessed within the first surface, this invention releases the accumulated stress of the quantum well active layer during its formation process, reducing the piezoelectric polarization intensity within the quantum well material, thereby increasing the overlap rate of the wave function and thus improving the luminous efficiency of the deep ultraviolet light-emitting diode. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the deep ultraviolet light-emitting diode provided in an embodiment of the present invention;

[0021] Figure 2 This is a scanning electron microscope image of the first microstructure in the deep ultraviolet light-emitting diode provided in the embodiment of the present invention;

[0022] Figure 3 This is a schematic cross-sectional view of the interface between the quantum well active layer and the electron blocking layer in the deep ultraviolet light-emitting diode provided in this embodiment of the invention.

[0023] Figure 4 This is a process flow diagram of the epitaxial growth method for deep ultraviolet light-emitting diodes provided in an embodiment of the present invention;

[0024] Figure 5 The graph shows the change in light output power as a function of current for two deep ultraviolet light-emitting diodes with different structures. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figures 1 to 5The present invention provides a deep ultraviolet light-emitting diode 100, comprising a substrate 11, an intrinsic layer 12, an N-type semiconductor layer 13, a quantum well active layer 14, an electron blocking layer 15, and a P-type semiconductor layer 16 stacked from bottom to top. The surface of the quantum well active layer 14 away from the N-type semiconductor layer 13 is a first surface, and a plurality of first microstructures 141 are disposed on the first surface, each of the first microstructures 141 being recessed in the first surface.

[0027] In this embodiment of the invention, a plurality of first microstructures 141 are formed on the first surface of the quantum well active layer 14 away from the N-type semiconductor layer 13, and the first microstructures 141 are recessed in the first surface. During the formation process, the plurality of first microstructures 141 release the accumulated stress of the quantum well active layer 14, reduce the piezoelectric polarization intensity inside the quantum well material, thereby improving the overlap rate of the wave function and thus improving the luminous efficiency of the deep ultraviolet light-emitting diode 100.

[0028] The technical solution of this application will now be described in conjunction with specific embodiments.

[0029] Please see Figure 1 , Figure 1 This is a schematic cross-sectional view of a deep ultraviolet light-emitting diode 100 provided in an embodiment of the present invention; wherein, the deep ultraviolet light-emitting diode 100 includes a substrate 11, an intrinsic layer 12, an N-type semiconductor layer 13, a quantum well active layer 14, an electron blocking layer 15, and a P-type semiconductor layer 16 stacked from bottom to top;

[0030] Specifically, the side surface of the quantum well active layer 14 away from the N-type semiconductor layer 13 is the first surface, and a plurality of first microstructures 141 are disposed on the first surface, each of the first microstructures 141 being recessed into the first surface.

[0031] In this embodiment of the invention, the substrate 11 is made of sapphire. Sapphire has many advantages: firstly, its production technology is mature and the device quality is good; secondly, sapphire has excellent stability and can be used in high-temperature growth processes; and finally, sapphire has high mechanical strength and is easy to handle and clean. Therefore, most processes generally use sapphire as the substrate 11.

[0032] In this embodiment of the invention, the intrinsic layer 12 includes a low-temperature buffer layer disposed on the substrate 11 and an aluminum nitride intrinsic layer disposed on the low-temperature buffer layer; wherein, the material of the low-temperature buffer layer is aluminum nitride, the growth temperature ranges from 400 to 800, and the thickness ranges from 10 nm to 50 nm; the aluminum nitride intrinsic layer is aluminum nitride, the growth temperature ranges from 1200 to 1400, and the thickness ranges from 500 nm to 4000 nm.

[0033] In this embodiment of the invention, the material of the N-type semiconductor layer 13 is N-type doped aluminum gallium nitride material, and the dopant is Si; wherein, the aluminum content in the N-type semiconductor layer 13 is between 20% and 90%, the thickness of the N-type semiconductor layer 13 is between 500 nm and 4000 nm, and the growth temperature of the N-type semiconductor layer 13 is between 900 and 1200 °C.

[0034] In this embodiment of the invention, the quantum well active layer 14 is disposed on the N-type semiconductor layer 13, and the growth temperature of the quantum well active layer 14 is between 900 and 1100.

[0035] Specifically, the quantum well active layer 14 is a periodically arranged AlGaN multilayer periodic structure. Each periodic structure includes a barrier layer and a well layer. The material of both the barrier layer and the well layer is aluminum gallium nitride. The only difference between the barrier layer and the well layer is the content of aluminum.

[0036] Furthermore, the period number of the quantum well active layer 14 is greater than 1 and less than 10; the thickness of the barrier layer ranges from 1 nm to 15 nm, and the mass percentage of aluminum in the barrier layer ranges from 30% to 90%; the thickness of the well layer ranges from 0.5 nm to 10 nm, and the mass percentage of aluminum in the well layer ranges from 20% to 70%.

[0037] Please see Figure 2 as well as Figure 3 , Figure 2 This is a scanning electron microscope (SEM) image of the first microstructure 141 in the deep ultraviolet light-emitting diode 100 provided in this embodiment of the invention. Figure 3 This is a schematic cross-sectional view of the interface between the quantum well active layer 14 and the electron blocking layer 15 in the deep ultraviolet light-emitting diode 100 provided in this embodiment of the invention; wherein, the side surface of the quantum well active layer 14 away from the N-type semiconductor layer 13 is the first surface, and a plurality of first microstructures 141 are disposed on the first surface, each of the first microstructures 141 being recessed in the first surface.

[0038] In this embodiment of the invention, the first microstructure 141 is prepared by a first process, which includes any one of photolithography, electron beam lithography, and plasma etching.

[0039] Specifically, photolithography is an important step in semiconductor device manufacturing. This step uses exposure and development to etch geometric patterns on a photoresist layer, and then uses etching to transfer the pattern on the photomask to the substrate 11. Electron beam lithography is a process that uses an electron beam to create patterns on a surface and is an extension of photolithography. Plasma etching utilizes plasma gas exposed in an electron region to release sufficient force to etch the surface of semiconductor materials when accelerated by an electric field.

[0040] In this embodiment of the invention, the width (d1) of the first microstructure 141 ranges from 1 nm to 100 nm, and the depth (h1) of the first microstructure 141 ranges from 1 nm to 200 nm; the cross-sectional shape of the first microstructure 141 includes any one of arc, square and hexagon.

[0041] Specifically, when the width (d1) of the first microstructure 141 is less than 1 nm, the first microstructure 141 cannot effectively release the stress accumulated inside the quantum well active layer 14. When the width (d1) of the first microstructure 141 is greater than 100 nm, the array formed by the first microstructure 141 will reduce the luminous efficiency of the active region in the quantum well active layer 14. When the depth (h1) of the first microstructure 141 is less than 1 nm, the first microstructure 141 cannot effectively release the stress accumulated inside the quantum well active layer 14. When the depth (h1) of the first microstructure 141 is greater than 200 nm, the array formed by the first microstructure 141 will reduce the luminous efficiency of the active region in the quantum well active layer 14.

[0042] Furthermore, multiple first microstructures 141 are arranged adjacently or spaced apart.

[0043] In this embodiment of the invention, an electron blocking layer 15 is disposed on the active layer 14 of the quantum well, and the growth temperature of the electron blocking layer 15 is between 700 and 1100°C; wherein, the electron blocking layer 15 is a single-layer AlGaN structure, the electron blocking layer 15 is a P-type doped semiconductor material, and magnesia pyrocene is used as the P-type dopant.

[0044] Furthermore, the percentage of aluminum in the electron blocking layer 15 ranges from 50% to 90%, and the thickness of the electron blocking layer 15 ranges from 5 nm to 200 nm.

[0045] Please see Figure 1 as well as Figure 3 The side surface of the electron blocking layer 15 near the quantum well active layer 14 is a second surface, and a plurality of second microstructures 152 are disposed on the second surface, each of the second microstructures 152 being recessed into the second surface.

[0046] Each second microstructure 152 is positioned opposite to each first microstructure 141; the width of each second microstructure 152 decreases linearly from the side closer to the quantum well active layer 14 to the side farther away from the quantum well active layer 14.

[0047] In this embodiment of the invention, when there are multiple first microstructures 141 on the side of the quantum well active layer 14 away from the N-type semiconductor layer 13, during the subsequent epitaxial growth of the electron blocking layer 15, the central region where the first microstructure 141 is located will not grow electron blocking material epitaxially, while the surrounding region of the first microstructure 141 will grow electron blocking material epitaxially. During the epitaxial growth process, the electron blocking material in the surrounding region of the first microstructure 141 slowly gathers towards the central region of the first microstructure 141, and finally merges above the central region of the first microstructure 141 to form multiple second microstructures 152. At this time, each second microstructure 152 is arranged opposite to each first microstructure 141, and the width (d2) of each second microstructure 152 decreases linearly from the side closer to the quantum well active layer 14 to the side away from the quantum well active layer 14.

[0048] Specifically, the width (d2) of the second microstructure 152 ranges from 0 to 100 nm, and the height (h2) of the second microstructure 152 ranges from 3 nm to 180 nm; wherein, the height (h2) of the second microstructure 152 is related to the width (d1) of its corresponding first microstructure 141, but is not related to the depth (h1) of the first microstructure 141; wherein, when the width (d1) of the first microstructure 141 is larger, the height (h2) of the second microstructure 152 corresponding to the first microstructure 141 is higher.

[0049] Furthermore, in existing deep ultraviolet (DUV) light-emitting diodes (LEDs) 100, as the Al content in the quantum well material increases, the light emission mode gradually changes from a transverse electric wave mode to a transverse magnetic wave mode. Light in the transverse electric wave mode can easily escape from the quantum well to the surface of the DUV 100. However, during the propagation of the transverse magnetic wave mode light from the quantum well to the surface of the DUV 100, the light in the transverse magnetic wave mode undergoes total internal reflection with the internal film layer of the DUV 100, thereby reducing the light extraction efficiency of the DUV 100.

[0050] To address the aforementioned technical problems, the deep ultraviolet light-emitting diode 100 provided by the present invention, due to the presence of the second microstructure 152, can form many tiny interfaces between the quantum well active layer 14 and the electron blocking layer 15, thereby improving the front light emission ratio of the deep ultraviolet light-emitting diode 100 and thus enhancing the light extraction efficiency of the deep ultraviolet light-emitting diode 100.

[0051] Furthermore, such as Figure 3 As shown, Figure 3 The example illustrates how the intensity of the emitted light is enhanced and the intensity of the totally internally reflected light is reduced by using the second microstructure 152. Specifically, when the height of the second microstructure 152 reaches 40 nm or more, the emission ratio of the emitted light can be increased by 29%.

[0052] In this embodiment of the invention, a P-type semiconductor layer 16 is disposed on an electron blocking layer 15, and the growth temperature of the P-type semiconductor layer 16 is between 700 and 1100 °C. The material of the P-type semiconductor layer 16 is P-type doped aluminum gallium nitride, the percentage of aluminum content in the P-type semiconductor layer 16 is between 20% and 60%, the thickness of the P-type semiconductor layer 16 is between 1 nm and 100 nm, and magnesia pyrocene is used as a dopant in the P-type semiconductor layer 16.

[0053] Furthermore, in this embodiment of the invention, the deep ultraviolet light-emitting diode 100 further includes an N-type electrode 17 and a P-type electrode 18;

[0054] In this structure, a stepped structure is formed between the quantum well active layer 14 and the N-type semiconductor layer 13, and the area of ​​the quantum well active layer 14 is smaller than the area of ​​the N-type semiconductor layer 13. The P-type electrode 18 is disposed on the P-type semiconductor layer 16, and the N-type electrode 17 is disposed at the stepped structure of the N-type semiconductor layer 13.

[0055] Accordingly, embodiments of the present invention also provide an epitaxial growth method for a deep ultraviolet light-emitting diode 100; please refer to [link to relevant documentation]. Figure 1 as well as Figure 4 , Figure 4 This is a process flow diagram of the epitaxial growth method for a deep ultraviolet light-emitting diode 100 provided in an embodiment of the present invention. Specifically, the epitaxial growth method includes:

[0056] S10, an intrinsic layer 12 is epitaxially grown on a substrate 11.

[0057] Specifically, S10 also includes:

[0058] First, a substrate 11 is provided, which is made of sapphire material. Then, a low-temperature buffer layer is grown on the substrate 11 at a temperature of 400–800°C, with a thickness ranging from 10 nm to 50 nm. Finally, the growth temperature is increased to between 1200 and 1400°C, and an intrinsic aluminum nitride layer is grown on the low-temperature buffer layer, with a thickness ranging from 500 nm to 4000 nm. The low-temperature buffer layer and the intrinsic aluminum nitride layer constitute the intrinsic layer 12, and both the low-temperature buffer layer and the intrinsic aluminum nitride layer are made of aluminum nitride.

[0059] S20, an N-type semiconductor layer 13 is epitaxially grown on the intrinsic layer 12.

[0060] Specifically, S20 also includes:

[0061] First, the growth temperature is lowered to between 900 and 1200 °C; then, an N-type semiconductor layer 13 is epitaxially grown on the intrinsic layer 12. The material of the N-type semiconductor layer 13 is N-type doped aluminum gallium nitride; wherein the aluminum content ranges from 20% to 90%, and the N-type dopant is Si.

[0062] S30, an active quantum well layer 14 is epitaxially grown on the N-type semiconductor layer 13.

[0063] Specifically, S30 also includes:

[0064] First, the growth temperature in the reaction chamber is reduced to between 900 and 1200 degrees Celsius, and a quantum well active layer 14 is epitaxially grown on the N-type semiconductor layer 13. The quantum well active layer 14 is a periodically arranged AlGaN multilayer periodic structure. Each periodic structure includes a barrier layer and a potential well layer. The material of both the barrier layer and the potential well layer is aluminum gallium nitride. The only difference between the barrier layer and the potential well layer is the content of aluminum.

[0065] The active quantum well layer 14 has a period number greater than 1 and less than 10; the thickness of the barrier layer ranges from 1 nm to 15 nm, and the mass percentage of aluminum in the barrier layer ranges from 30% to 90%; the thickness of the well layer ranges from 0.5 nm to 10 nm, and the mass percentage of aluminum in the well layer ranges from 20% to 70%.

[0066] S40, multiple first microstructures 141 are formed on the active layer 14 of the quantum well.

[0067] Specifically, S40 also includes:

[0068] After the quantum well active layer 14 is grown, a plurality of periodically patterned first microstructures 141 are formed on the surface of the quantum well active layer 14 away from the N-type semiconductor layer 13 by any one of the conventional photolithography process, electron beam exposure process and plasma etching process.

[0069] The width of the first microstructure 141 ranges from 1 nm to 100 nm, the depth of the first microstructure 141 ranges from 1 nm to 200 nm, and the cross-sectional shape of the first microstructure 141 is cylindrical, square, or hexagonal.

[0070] S50, an electron blocking layer 15 is epitaxially grown on the active layer 14 of the quantum well.

[0071] Specifically, the S50 also includes:

[0072] First, the epitaxial wafer with multiple first microstructures 141 is cleaned and placed into the reaction chamber; then, the temperature of the reaction chamber is maintained between 700 and 1100 degrees Celsius, and an electron blocking layer 15 is epitaxially grown on the quantum well active layer 14; wherein, the electron blocking layer 15 is a single-layer AlGaN structure, the electron blocking layer 15 is a P-type doped semiconductor material, and magnesia pyrocene is used as the P-type dopant.

[0073] Specifically, the percentage of aluminum content in the electron blocking layer 15 ranges from 50% to 90%, and the thickness of the electron blocking layer 15 ranges from 5 nm to 200 nm.

[0074] Furthermore, during the epitaxial growth of the electron blocking layer 15, as the thickness of the electron blocking layer 15 continuously increases, the electron blocking material continuously heals, thereby generating multiple second microstructures 152 on the surface of the electron blocking layer 15 near the quantum well active layer 14, which are positioned one-to-one with the first microstructure 141. The thickness of the second microstructures 152 is between 3 nm and 180 nm. The thickness of the second microstructures 152 is related to the width of the first microstructure 141.

[0075] S60, a P-type semiconductor layer 16 is epitaxially grown on the electron blocking layer 15.

[0076] Specifically, the S50 also includes:

[0077] The growth temperature is maintained between 700 and 1100 °C, and a P-type semiconductor layer 16 is epitaxially grown on the electron blocking layer 15. The material of the P-type semiconductor layer 16 is P-type doped aluminum gallium nitride, the percentage of aluminum composition in the P-type semiconductor layer 16 ranges from 0 to 100%, the thickness of the P-type semiconductor layer 16 ranges from 1 nm to 100 nm, and magnesium pyrocene is used as the P-type dopant in the P-type semiconductor layer 16.

[0078] Next, an N-type electrode 17 is disposed at the stepped structure of the N-type semiconductor layer 13, with the N-type electrode 17 being disposed opposite to and spaced apart from the quantum well active layer 14; finally, a P-type electrode 18 is formed on the P-type semiconductor layer 16.

[0079] In this embodiment of the invention, after the deep ultraviolet light-emitting diode 100 is fabricated, it is compared with the deep ultraviolet light-emitting diode 100 of the prior art. The light output power (mW) of the two deep ultraviolet light-emitting diodes 100 is tested under different driving currents (mA).

[0080] Embodiments of the present invention:

[0081] The film structure of the deep ultraviolet light-emitting diode 100 provided by the present invention has approximately the same structure and materials from bottom to top, from the substrate 11 to the P-type semiconductor layer 16, as shown below:

[0082] Substrate 11 is made of sapphire.

[0083] Intrinsic layer 12 is made of aluminum nitride and has a thickness of 2000 nm.

[0084] The N-type semiconductor layer 13 is made of Si-type doped aluminum gallium nitride material, wherein the Al component in the N-type semiconductor layer 13 accounts for 50% of the mass percentage of the N-type semiconductor layer 13 and the thickness is 2500 nm.

[0085] The quantum well active layer 14 has a thickness of 1 nm and an Al component mass percentage of 50% in the potential well layer, and a barrier layer thickness of 2 nm and an Al component percentage of 60% in the barrier layer; wherein, the first microstructure 141 has a width of 20 nm, a depth of 50 nm, and a circular cross-sectional shape.

[0086] The electron blocking layer 15 is a single-layer AlGaN structure with a thickness of 120 nm and an Al composition of 60% by mass. The second microstructure 152 has a maximum width of 20 nm and a height of 100 nm.

[0087] The material of the P-type semiconductor layer 16 is P-type doped aluminum gallium nitride. The mass percentage of aluminum in the P-type semiconductor layer 16 is 40%, the thickness is 100 nm, and magnesium pyrocene is used as the p-type dopant.

[0088] Furthermore, using conventional methods, N-type electrodes 17 of the same material are disposed on the N-type semiconductor layer 13, and P-type electrodes 18 of the same material are disposed on the P-type semiconductor layer 16 to form a complete epitaxial chip structure. The specific process is not described in detail here. Both the N-type electrodes 17 and the P-type electrodes 18 are multilayer composite metal materials.

[0089] Comparative Example:

[0090] The deep ultraviolet light-emitting diode 100 prepared by conventional processes does not have the first microstructure 141 and the second microstructure 152; the other film structures of the comparative embodiment are the same as the other film structures of the embodiments of the present invention.

[0091] Please see Figure 5 , Figure 5 The graphs show the optical output power of two deep ultraviolet light-emitting diodes 100 with different structures as a function of current. Specifically, under different driving currents (mA), the optical output power (mW) of each deep ultraviolet light-emitting diode 100 as a function of driving current was measured. Figure 5As shown.

[0092] Specifically, by Figure 5 It can be seen that chip tests were performed on a conventional deep ultraviolet light-emitting diode 100 (comparative embodiment) and a deep ultraviolet light-emitting diode 100 with a patterned quantum well (in this invention embodiment).

[0093] Specifically, at an injection current of 100mA, the conventional deep ultraviolet (DUV) light-emitting diode (LED) 100 has a light output power of 18.0mW; while the DUV 100 with a patterned quantum well structure has a light output power of 26.1mW, representing a 45% increase in output power. This is because the patterned quantum well structure releases stress in the quantum well region during fabrication, reducing the piezoelectric polarization intensity within the material. Furthermore, the patterned structure also improves the front-side light emission ratio of the DUV 100, thereby enhancing its light extraction efficiency.

[0094] In summary, unlike existing technologies, the deep ultraviolet (DUV) light-emitting diode 100 with a patterned quantum well structure proposed in this invention releases the accumulated stress in the quantum well region during the etching process, reducing the piezoelectric polarization intensity inside the material and thus improving the wavefunction overlap rate. Furthermore, the patterned structure also forms numerous micro-interfaces in the active region, increasing the front-side light emission ratio of the DUV 100 and further enhancing its light extraction efficiency.

[0095] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0096] The above embodiments merely illustrate implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A deep ultraviolet light-emitting diode, characterized in that, It includes, from bottom to top, a substrate, an intrinsic layer, an N-type semiconductor layer, a quantum well active layer, an electron blocking layer, and a P-type semiconductor layer; Wherein, the surface of the quantum well active layer away from the N-type semiconductor layer is a first surface, and a plurality of first microstructures are disposed on the first surface, each of the first microstructures being recessed into the first surface; the first microstructures are fabricated by a first process, the first process including any one of photolithography, electron beam lithography, and plasma etching; the width of the first microstructure ranges from 1 nm to 100 nm, and the depth of the first microstructure ranges from 1 nm to 200 nm; the cross-sectional shape of the first microstructure includes any one of arc, square, and hexagon. The electron blocking layer has a second surface on the side closest to the quantum well active layer. A plurality of second microstructures are disposed on the second surface. Each second microstructure is recessed in the second surface and is disposed opposite to each first microstructure. The width of each second microstructure decreases linearly from the side closest to the quantum well active layer to the side furthest from the quantum well active layer.

2. The deep ultraviolet light-emitting diode according to claim 1, characterized in that, Multiple first microstructures are arranged adjacently or spaced apart.

3. The deep ultraviolet light-emitting diode according to claim 1, characterized in that, The quantum well active layer is a periodically arranged AlGaN multilayer periodic structure, and each periodic structure includes a barrier layer and a well layer. Wherein, the number of periods of the quantum well active layer is greater than 1 and less than 10; the thickness of the barrier layer is in the range of 1 nm to 15 nm, and the mass percentage of aluminum in the barrier layer is in the range of 30% to 90%; the thickness of the potential well layer is in the range of 0.5 nm to 10 nm, and the mass percentage of aluminum in the potential well layer is in the range of 20% to 70%.

4. The deep ultraviolet light-emitting diode according to claim 1, characterized in that, The height of the second microstructure ranges from 3 nm to 180 nm.

5. The deep ultraviolet light-emitting diode according to claim 1, characterized in that, The electron blocking layer is made of P-type doped AlGaN, the mass percentage of aluminum in the electron blocking layer ranges from 50% to 90%, and the thickness of the electron blocking layer ranges from 5 nm to 200 nm.

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