Composite periodic electrode used as deep ultraviolet LED P-type electrode and deep ultraviolet LED

Abstract

The utility model relates to the technical field of deep ultraviolet LEDs, in particular to a composite periodic electrode used as a deep ultraviolet LED P-type electrode and a deep ultraviolet LED. The utility model provides a composite periodic electrode used as a deep ultraviolet LED P-type electrode, and the patterns of the composite periodic electrode are distributed at equal intervals in a longitude and latitude manner, so that the composite periodic electrode is formed by arranging a plurality of rectangular grids in an array manner; each rectangular grid comprises four rectangular edges with the line width of 3-5 microns, and the intersection parts of the end parts of the rectangular edges are connected by adopting round points with the diameter of 10-20 microns; and the thickness of the composite periodic electrode is (50-150) nm. According to the deep ultraviolet LED composite periodic electrode, the design of dot-line combination and composite ordered longitude and latitude arrangement is adopted for the patterns, so that the light transmission effect of front deep ultraviolet light can be remarkably improved, and the deep ultraviolet LED with high light extraction efficiency can be obtained.

Description

Technical Field

[0001] This application relates to the technical field of deep ultraviolet LED, and particularly to a composite periodic electrode used as a P-type electrode of a deep ultraviolet LED and a deep ultraviolet LED. Background Art

[0002] In recent years, AlGaN-based deep ultraviolet LEDs have received extensive attention and research internationally due to their unique wavelength advantages and broad application prospects. However, the practical application and large-scale promotion of current deep ultraviolet LEDs still face many technical challenges:

[0003] One of the important limiting factors is the low light extraction efficiency, mainly due to the total reflection at the interface between the deep ultraviolet LED material and air, strong light absorption by the metal electrode, etc., which makes the number of photons passing through the front of the deep ultraviolet LED very limited, thus reducing the external quantum efficiency of the device. Traditional metal electrodes hinder the transmission of light.

[0004] In addition, using visible light transparent conductive materials, such as ITO (indium tin oxide), etc. as electrode materials, their absorption of deep ultraviolet photons is significant, resulting in poor transmittance of deep ultraviolet light, which is not conducive to the preparation of electrodes for deep ultraviolet LEDs.

[0005] In summary, currently, the preparation of deep ultraviolet LED electrodes mainly faces the following problems: First, traditional metal electrodes have strong light absorption in the deep ultraviolet band, making the number of photons passing through the front of the deep ultraviolet LED very limited, affecting the light extraction efficiency; Second, existing visible light transparent conductive materials such as ITO (indium tin oxide), etc. have significant absorption of deep ultraviolet photons, resulting in poor transmittance of deep ultraviolet light, making the performance of existing electrode conductive materials in the deep ultraviolet band not ideal and unable to well meet the preparation requirements of electrodes. Summary of the Invention

[0006] To solve the deficiencies of the prior art mentioned in the background art, this application provides a composite periodic electrode used as a P-type electrode of a deep ultraviolet LED, and its technical solution is as follows:

[0007] This application provides a composite periodic electrode used as a P-type electrode of a deep ultraviolet LED. The pattern of the composite periodic electrode is distributed in equal-spacing longitude and latitude, making it arranged in an array of several rectangular grids; the rectangular grid includes four rectangular sides with a line width of 3 - 5 μm, and the intersections of the ends of the rectangular sides are connected by circles with a diameter of 10 - 20 μm; the thickness of the composite periodic electrode is (50 - 150) nm.

[0008] In some embodiments, the rectangular grid is a square structure with a side length of 30 - 75 μm.

[0009] In some embodiments, the rectangular grid is a square structure with a side length of 50 μm; a central dot is provided at the center of the rectangular grid, and the central dot is connected to any one of the four rectangular sides by a connecting line; wherein, the connecting lines of each rectangular grid are parallel to each other, the line widths of the connecting line and the rectangular side are 3 - 5 μm, and the diameter of the central dot is 10 - 20 μm.

[0010] In some embodiments, the rectangular grid is a square structure composed of four rectangular sides, and its side length is 30 μm.

[0011] In some embodiments, the material of the composite periodic electrode is a conductive electrode material.

[0012] In some embodiments, the conductive electrode material is a titanium-aluminum-titanium electrode material.

[0013] The present application also provides a deep ultraviolet LED, and the P-type electrode of the deep ultraviolet LED adopts the composite periodic electrode as described above.

[0014] In some embodiments, it includes an epitaxial wafer, an N-type electrode, and a P-type electrode; the epitaxial wafer sequentially includes a substrate, a buffer layer, an N-type semiconductor electron injection layer, a multi-quantum well active layer, and a P-type semiconductor hole injection layer from bottom to top; wherein, a trench extending to the N-type semiconductor electron injection layer is provided on the upper surface of the P-type semiconductor hole injection layer, so that an exposed area is formed on the upper surface of the N-type semiconductor electron injection layer; the N-type electrode is provided on the surface of the exposed area, and the P-type electrode is provided on the surface of the P-type semiconductor hole injection layer.

[0015] In some embodiments, a circular trench extending downward to the N-type semiconductor electron injection layer is provided along the outer periphery of the upper surface of the P-type semiconductor hole injection layer, so that an annular exposed area is formed on the upper surface of the N-type semiconductor electron injection layer; wherein, an annular N-type electrode is provided on the surface of the exposed area.

[0016] In some embodiments, the N-type semiconductor electron injection layer is an N-type aluminum gallium nitride layer;

[0017] In some embodiments, the P-type semiconductor hole injection layer is a P-type gallium nitride layer.

[0018] A composite periodic electrode used as the P-type electrode of a deep ultraviolet LED provided by the present application has the following technical effects compared with the existing technology:

[0019] The pattern of the deep ultraviolet LED composite periodic electrode adopts a design of combining dots and lines and a composite and ordered longitude and latitude arrangement, which can significantly improve the light transmission effect of the front deep ultraviolet light, and is beneficial to obtaining a deep ultraviolet LED with a high light extraction efficiency.

[0020] Other features and beneficial effects of the present application will be described in the subsequent specification. Moreover, some of them will become apparent from the specification or be understood by implementing the present application. The objectives and other beneficial effects of the present application can be achieved and obtained through the structures and / or components pointed out in the specification and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 Schematic diagram of the structure of a deep ultraviolet LED with a composite periodic electrode prepared for the present application;

[0023] Figure 2 Schematic diagram of the structure of the composite periodic electrode prepared in Embodiments 1-3 of the present application;

[0024] Figure 3 Schematic diagram of the structure of the composite periodic electrode prepared in Embodiments 4-6 of the present application;

[0025] Figure 4 SEM (scanning electron microscope) image of the composite periodic electrode prepared in Embodiment 1 of the present application;

[0026] Figure 5 EL (electroluminescence) spectrogram measured at voltages of 14, 16, and 18 V in Embodiment 1 of the present application;

[0027] Figure 6 IV (current-voltage) graph of the composite periodic electrodes prepared in Embodiments 1-6 of the present application and a traditional disk electrode with a diameter of 300 μm;

[0028] Figure 7 EL mapping graph of the composite periodic electrodes prepared in Embodiments 1-6 of the present application and a traditional disk electrode with a diameter of 300 μm.

[0029] Reference Signs in the Drawings:

[0030] 100 - Substrate, 200 - Buffer layer, 300 - N-type semiconductor electron injection layer, 400 - Multiple quantum well active layer, 500 - P-type semiconductor hole injection layer, 600 - N-type electrode, 700 - Composite periodic electrode, 800 - Trench. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0032] This application also provides the following embodiments and comparative examples to verify the beneficial effects of this application:

[0033] Embodiment 1

[0034] The LED device with a composite periodic electrode structure and its preparation method in this embodiment include the following steps:

[0035] Step 1: First, place the epitaxial wafer of the chip in acetone solution and ultrasonicate for 5 minutes. The ultrasonic power is 240W, and the temperature is 25 - 40°C;

[0036] Among them, the epitaxial wafer includes an Al2O3 substrate, an AlN buffer layer (aluminum gallium nitride (~1100nm)), an N-type semiconductor electron injection layer (N-type aluminum gallium nitride layer, specifically n-Al 0.5 Ga 0.05 N (~1400nm)), a multi-quantum well active layer (specifically 5 periods MQWs, containing 10nm-Al 0.45 Ga 0.55 N, 3nm-Al 0.35 Ga 0.65 N), and a P-type semiconductor hole injection layer (P-type gallium nitride layer, 120nm thick);

[0037] Step 2: After taking out the epitaxial wafer, place it in anhydrous ethanol and deionized water for ultrasonication in sequence. The ultrasonication time is also 5 minutes, the ultrasonic power is 240W, and the temperature is 25°C:

[0038] Step 3: Blow dry the cleaned epitaxial wafer with nitrogen;

[0039] Step 4: Place the dried epitaxial wafer in MOCVD to grow 100nm SiO2 as a mask template;

[0040] Step 5: Place the epitaxial wafer after growing SiO2 in a spin coater, and spin coat an adhesion promoter on the surface of the P-type semiconductor hole injection layer. The spin coating process is carried out with low-speed spin coating and high-speed spin coating in sequence. The rotation speed of the spin coater is set to 1000r / min for low speed, with a duration of 3s, and 3000r / min for high speed, with a duration of 30s;

[0041] Step Six: After the spin-coating of the adhesion promoter, spin-coat the surface of the P-type semiconductor hole injection layer with photoresist. The spin-coating process is carried out in sequence with low-speed spin-coating and high-speed spin-coating. The rotation speed of the spin coater is set to 1000 r / min for low speed, with a duration of 3 s, and 3000 r / min for high speed, with a duration of 30 s;

[0042] Step Seven: Place the spin-coated epitaxial wafer on a hot plate for baking. The temperature is set to 100 °C and the time is 4 min;

[0043] Step Eight: Next, use the MLA lithography system to perform lithography on the epitaxial wafer to obtain the required mesa pattern;

[0044] Step Nine: Place the exposed pattern in the developer for dissolution for 2 min, then rinse with deionized water and dry with nitrogen to obtain the mesa pattern required for the P-type electrode.

[0045] Step Ten: Place the patterned epitaxial wafer on a hot plate for baking. The temperature is set to 120 °C and the time is 15 min;

[0046] Step Eleven: According to the mesa pattern, perform ICP etching on the epitaxial wafer with the mesa pattern to the middle of the N-type GaN layer;

[0047] Step Twelve: After repeating the cleaning process of Steps One to Three, repeat the photoresist spin-coating of Steps Five to Nine;

[0048] Step Thirteen: Next, use the MLA lithography system to perform lithography on the P-type semiconductor hole injection layer of the epitaxial wafer to obtain the required lithography pattern of the P-type electrode. The specific process is as follows:

[0049] (1) First, place the epitaxial wafer on the displacement platform and zero the displacement platform of the MLA lithography system;

[0050] (2) After zeroing, adjust the focal plane of the microlens array to align with the exposure plane through the computer;

[0051] (3) Next, adjust the distance between the focal plane of the microlens array and the exposure plane to 0.5 mm;

[0052] (4) Then, control the MLA lithography system through the computer to perform lithography on the epitaxial wafer to obtain a rectangular grid pattern with a dot-line combination period (i.e., side length) of 50 μm;

[0053] (5) Place the exposed pattern in the developer for dissolution for 2 min;

[0054] (6) Rinse the dissolved epitaxial wafer with pure water and dry with nitrogen to obtain the required lithography pattern.

[0055] AsFigure 2 , Figure 4 As shown, through the parameter design and control of the MLA lithography system, the formed lithography pattern is as follows: The lithography pattern is located in the middle of the P-type semiconductor hole injection layer, and it is distributed in an equidistant latitude and longitude pattern, consisting of 36 rectangular grids (6 in the horizontal row and 6 in the vertical row). The rectangular grid is a square structure composed of four rectangular sides, and its side length L is 50 μm, the width D1 of the rectangular border line is 4 μm, and the intersections at the ends of the rectangular sides are connected by dots with a diameter R1 of 15 μm, forming a composite periodic structure composed of a combination of dots and lines.

[0056] Step Fourteen: After subjecting the epitaxial wafer with the lithography pattern to ICP etching and then plating with titanium-aluminum-titanium, a composite periodic electrode can be obtained. Among them, the thickness of the composite periodic electrode is 70 nm (Ni / Au are 20 / 50 nm respectively);

[0057] Step Fifteen: Place the fabricated composite periodic electrode in an annealing furnace and perform rapid thermal annealing treatment for 10 min at a temperature of 450 °C in a nitrogen environment;

[0058] Step Sixteen: Repeat Step Thirteen and then use the MLA lithography system to perform lithography on the epitaxial wafer to obtain the required N-type electrode pattern;

[0059] Step Seventeen: After placing the exposed pattern in a developer solution for dissolution for 2 min, rinse it with pure water and then dry it with oxygen to obtain the required N-type electrode pattern;

[0060] Step Eighteen: Use an electron beam thermal evaporation device to plate the epitaxial wafer with the lithography pattern with titanium-aluminum-titanium to obtain the N-type electrode. Among them, the thickness of the N-type electrode is 235 nm (Ti / AI / Ti are 30 / 200 / 5 nm respectively);

[0061] Step Nineteen: Place the fabricated N-type electrode in an annealing furnace and perform rapid thermal annealing treatment for 90 s at a temperature of 850 °C in a nitrogen environment to obtain a complete LED device.

[0062] Among them, the structure of the fabricated complete deep ultraviolet LED is as Figure 1 shown:

[0063] The epitaxial wafer sequentially includes a substrate 100, a buffer layer 200, an N-type semiconductor electron injection layer 300, a multi-quantum well active layer 400, and a P-type semiconductor hole injection layer 500 from bottom to top; wherein, along the outer periphery of the upper surface of the P-type semiconductor hole injection layer 500, an annular groove 800 extending downward to the N-type semiconductor electron injection layer 300 is provided, so that an annular exposed area is formed on the upper surface of the N-type semiconductor electron injection layer 300; an annular N-type electrode 600 is provided on the surface of the exposed area; a P-type electrode is provided on the surface of the P-type semiconductor hole injection layer, and the P-type electrode is a composite periodic electrode 700 prepared by the preparation method as described above.

[0064] Example 2

[0065] Prepared by the method of Example 1, the difference between this comparative example and Example 1 is only that: as Figure 2 shown, the side length L of the rectangular grid pattern is 75 μm.

[0066] Example 3

[0067] Prepared by the method of Example 1, the difference between this comparative example and Example 1 is only that: as Figure 2 shown, the side length L of the rectangular grid pattern is 30 μm.

[0068] Example 4

[0069] Prepared by the method of Example 1, the difference between this comparative example and Example 1 is only that:

[0070] as Figure 3 shown: The lithography pattern is located in the middle of the P-type semiconductor hole injection layer, and it is distributed in an equidistant longitude and latitude pattern, consisting of 16 rectangular grids (4 in a horizontal row and 4 in a vertical row). The side length L of the rectangular grid is 75 μm, the width D1 of the rectangular side line is 4 μm, and the intersection of the ends of the rectangular sides is connected by a dot with a diameter R1 of 15 μm; a central dot is provided at the center of the rectangular grid, and the central dot is connected to any one of the four rectangular sides by a connecting line; wherein, the connecting lines of each rectangular grid in the lithography pattern are parallel to each other, the line width D2 of the connecting line is 4 μm, and the diameter R2 of the central dot is 15 μm.

[0071] Example 5

[0072] Prepared by the method of Example 1, the difference between this comparative example and Example 1 is only that:

[0073] as Figure 3As shown, the photolithography pattern is located in the middle of the P-type semiconductor hole injection layer. It is distributed in an equidistant latitude and longitude pattern and consists of 36 rectangular grids (6 in the horizontal row and 6 in the vertical row). The side length L of the rectangular grid is 50 μm, the width D1 of the rectangular border line is 4 μm, and the ends of the rectangular sides are connected by dots with a diameter R1 of 15 μm. A central dot is provided at the center of the rectangular grid, and the central dot is connected to any one of the four rectangular sides by a connecting line. Among them, the connecting lines of each rectangular grid in the photolithography pattern are parallel to each other. The width D2 of the connecting line is 4 μm, and the diameter R2 of the central dot is 15 μm.

[0074] Example 6

[0075] The method of Example 1 was used for preparation. The difference between this comparative example and Example 1 is only that:

[0076] As Figure 3 shown, the photolithography pattern is located in the middle of the P-type semiconductor hole injection layer. It is distributed in an equidistant latitude and longitude pattern and consists of 100 rectangular grids (10 in the horizontal row and 10 in the vertical row). The side length L of the rectangular grid is 30 μm, the width D1 of the rectangular border line is 4 μm, and the ends of the rectangular sides are connected by dots with a diameter R1 of 15 μm. A central dot is provided at the center of the rectangular grid, and the central dot is connected to any one of the four rectangular sides by a connecting line. Among them, the connecting lines of each rectangular grid in the photolithography pattern are parallel to each other. The width D2 of the connecting line is 4 μm, and the diameter R2 of the central dot is 15 μm.

[0077] Performance tests were carried out on the products obtained from the above examples and the comparative example (the existing deep ultraviolet LED with a disc electrode structure).

[0078] A deep ultraviolet LED with a traditional disc electrode with a diameter of 300 μm was set as a comparative example. The difference in its structure from the deep ultraviolet LED obtained in Example 1 is only that: its P-type electrode does not use a composite periodic electrode, but uses a disc-shaped electrode with a diameter of 300 μm, and the electrode material is also nickel-gold.

[0079] (1) EL spectrogram of the composite periodic electrode

[0080] At an emission wavelength of 273 nm and a FWHM (full width at half maximum) of 12.36 nm, under the conditions of voltages of 14, 16, and 18 V, the EL spectrograms of the test samples were measured. Figure 5 are the EL spectrograms measured for Example 1 at voltages of 14, 16, and 18 V respectively;

[0081] From Figure 5 it can be seen that: the deep ultraviolet LED obtained in Example 1 has good luminous performance;

[0082] (2)IV diagrams of the products obtained in the examples and the deep ultraviolet LEDs with the existing disc electrode structure

[0083] The test method and test conditions are as follows: Two probes connected with positive pressure and negative pressure are respectively inserted into the P-type electrode and N-type electrode of the prepared deep ultraviolet LED, and the test voltage ranges from 0V to 20V.

[0084] The measured IV diagrams are as Figure 6 shown, where the abscissa is voltage and the ordinate is current; C0 corresponds to the comparative example, A1 - A3 correspond to Examples 1 - 3, and B1 - B3 correspond to Examples 4 - 6.

[0085] From Figure 6 it can be seen that

[0086] By comparing the disc-shaped P-type electrode in the comparative example and the P-type electrode in the examples (i.e., the composite periodic electrode), it can be found that the rising trend of the I-V curve of the P-type electrode in the examples is more obvious. At the same voltage, the current flowing through the LED with the disc-shaped P-type electrode is lower and the light-emitting performance is weaker. Summarizing the above results: Compared with the deep ultraviolet LEDs with the traditional disc electrodes with a diameter of 300μm in the comparative example, the products obtained in the examples of the present application have a small resistance, indicating that they can effectively conduct current, improve the photoelectric conversion efficiency of the device, have better device performance, and show that more deep ultraviolet photons are emitted. Among them, Example 3 is the best, and Examples 2 and 5 are only slightly inferior and can also reach a very good level

[0087] (3)EL mapping diagrams of the products obtained in the examples and the deep ultraviolet LEDs with the existing disc electrode structure

[0088] The test method and test conditions are as follows: Two probes connected with positive pressure and negative pressure are respectively inserted into the P-type electrode and N-type electrode, and a voltage of +18V is applied;

[0089] The measured EL mapping diagrams are as Figure 7 shown, where C0 corresponds to the comparative example, A1 - A3 correspond to Examples 1 - 3, and B1 - B3 correspond to Examples 4 - 6; "18V" in the figure respectively represents the voltage value applied to the LED device.

[0090] From Figure 7 it can be seen that

[0091] Compared with the traditional circular electrode in the comparative example, the light radiation of the examples of the present application is enhanced at 18V, and the light-emitting intensity of the comparative example is weak; and among these examples, A3, B1, and B2 have stronger light radiation at 18V.

[0092] For the traditional circular electrode in the comparative example, when current is injected from the P-type electrode, due to the large area and no gaps of the circular electrode, it has a blocking and absorbing effect on the photons generated by radiative recombination. Therefore, the photons can only exit from the periphery of the circular electrode, resulting in a weak luminescence intensity. When the composite periodic electrode in the embodiment is adopted, the P-type electrodes in both arrangement modes have an obvious enhancing effect on the light extraction efficiency of the deep ultraviolet LED, and the light radiation generated by A3, B1, and B2 is the strongest. It shows that the composite periodic electrode can not only improve luminescence but also improve thermal management, which helps to more effectively extract heat from the LED chip, thereby reducing the working temperature of the device and improving its stability and lifespan.

[0093] Summarizing from the above results: Compared with the deep ultraviolet LED with the traditional disk electrode with a diameter of 300 μm in the comparative example, for the product prepared in the embodiment of the present application, its front light transmission effect is significantly improved, which can effectively reduce the light absorption by the electrode metal, reduce the light absorption loss, and improve the light extraction efficiency. In terms of light transmission performance and light extraction efficiency, compared with other embodiments, the comprehensive performance of Embodiment 5 is the best, and that of Embodiment 3 is the second. Although in Figure 6 Embodiment 2 is comparable to Embodiment 5, it is obvious that its light transmission performance is lower than that of Embodiment 5 and Embodiment 3. From the comprehensive performance perspective, Embodiment 5 and Embodiment 3 are the preferred choices.

[0094] The technical solution of the present application at least includes the following objectives, design concepts, and beneficial effects:

[0095] The present application provides a highly efficient interconnected integrated deep ultraviolet LED composite periodic electrode and its preparation method. Adopting the solution of the present application can not only reduce the light absorption loss in the deep ultraviolet LED but also effectively conduct current, while maintaining a high degree of stability of the structure and performance of the deep ultraviolet LED device.

[0096] The design principle of the solution of the present application aims to reduce the light absorption by the metal, improve the light extraction efficiency, and alleviate the current crowding problem. The preparation process is realized by using the MLA manufacturing technology, so as to achieve rapid and efficient structure acquisition, simplify the process, and improve the overall performance of the device. This design aims to optimize the performance of optoelectronic devices to meet the actual application requirements.

[0097] Compared with the existing deep ultraviolet LED with a traditional electrode structure, the deep ultraviolet LED composite periodic electrode prepared in the present application adopts a design of combining dots and lines and a composite and ordered warp and weft arrangement:

[0098] The pattern of the composite periodic electrode is distributed in a warp and weft manner at equal intervals, making it arranged in an array of several rectangular grids; each rectangular grid includes four rectangular sides with a line width of 3-5 μm, and the intersections of the ends of the rectangular sides are connected by dots with a diameter of 10-20 μm; with such a design, the front-side light transmission can be significantly improved, which is beneficial to obtaining a deep ultraviolet LED with a high light extraction efficiency. The specific design concept and beneficial effects are as follows:

[0099] 1. The design of the composite periodic electrode significantly improves the front-side light extraction efficiency. This design not only makes the current expand more uniformly inside the device, avoiding problems such as current congestion and local overheating, thereby improving the stability and lifespan of the device;

[0100] 2. Compared with the traditional disordered arrangement of nanowires, the ordered arrangement characteristic of the electrode prepared in this application further optimizes the current transmission performance. The ordered arrangement not only reduces the resistance but also improves the current transmission efficiency, significantly enhancing the overall performance of the device;

[0101] 3. The dot-line combination grid structure of the composite electrode plays a composite effect in current expansion. By precisely controlling the shape and arrangement of the electrode, efficient current expansion and distribution are achieved, thereby improving the optoelectronic conversion efficiency of the device;

[0102] 4. In addition, the above-mentioned composite periodic electrode is prepared with the help of an MLA (microlens array) device. The method of this application realizes rapid manufacturing with the help of an MLA (microlens array) device, which not only greatly improves the production efficiency and reduces the production cost, facilitating large-scale industrial production, but also the designed electrode has a compact structure and stable performance, is suitable for the preparation of various deep ultraviolet LED devices, and has a wide application prospect.

[0103] It should be noted that:

[0104] In this article, "~" is used to represent a numerical range, and the two endpoint values are included within the represented range.

[0105] The MLA lithography system is fully called the microlens array lithography system, which is an existing device. By setting the corresponding preparation procedures and processes with the existing MLA lithography system in this application, the required electrode can be prepared;

[0106] ICP etching is fully called inductively coupled plasma etching, which is an existing process method realized by using an existing plasma etching machine, and its functional principle will not be elaborated here;

[0107] In addition to the titanium-aluminum-titanium conductive electrode material selected for the composite periodic electrode in the above specific embodiment, other conductive electrode materials can also be selected, such as nickel-aluminum-nickel gold, ITO, etc., and the titanium-aluminum-titanium conductive electrode material is preferred.

[0108] In summary, the specific parameters, some common reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments under the concept of this application, rather than a limitation thereof; those skilled in the art can make adaptive adjustments within the concept and protection scope of this application.

[0109] In addition, unless otherwise specified, the raw materials used can also be conventional commercially available products in the art or prepared by conventional methods in the art; that is, the reagents and instruments used in this embodiment are not specified with information such as the manufacturer, and are all conventional products that can be obtained through market purchase.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, rather than a limitation thereof; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A composite periodic electrode used as a P-type electrode for deep ultraviolet LEDs, characterized in that , The pattern of the composite periodic electrode is distributed in a warp and weft manner at equal intervals, making it arranged in an array of a number of rectangular grids; the rectangular grid includes four rectangular sides with a line width of 3-5 μm, and the intersections of the ends of the rectangular sides are connected by round dots with a diameter of 10-20 μm; The thickness of the composite periodic electrode is 50-150 nm.

2. The composite periodic electrode used as a P-type electrode of a deep ultraviolet LED according to claim 1, wherein: The rectangular grid is a square structure with a side length of 30-75 μm.

3. The composite periodic electrode used as a P-type electrode for deep ultraviolet LEDs according to claim 1, wherein: The rectangular grid is a square structure with a side length of 50 μm. A central round dot is provided at the center of the rectangular grid, and the central round dot is connected to any one of the four rectangular sides by a connecting line; wherein, the connecting lines of each rectangular grid are parallel to each other, the line width of the connecting line and the rectangular side is 3-5 μm, and the diameter of the central round dot is 10-20 μm.

4. The composite periodic electrode used as the P-type electrode of the deep ultraviolet LED according to claim 1, characterized in that: The rectangular grid is a square structure composed of four rectangular sides, and its side length is 30 μm.

5. The composite periodic electrode used as the P-type electrode of the deep ultraviolet LED according to any one of claims 1-4, characterized in that: The material of the composite periodic electrode is a conductive electrode material.

6. The composite periodic electrode used as the P-type electrode of the deep ultraviolet LED according to claim 5, wherein: The conductive electrode material is a titanium-aluminum-titanium electrode material.

7. A deep ultraviolet LED, characterized in that: The P-type electrode of the deep ultraviolet LED adopts the composite periodic electrode as described in any one of claims 1-6.

8. The deep ultraviolet LED according to claim 7, wherein: It includes an epitaxial wafer, an N-type electrode, and a P-type electrode; The epitaxial wafer sequentially includes a substrate, a buffer layer, an N-type semiconductor electron injection layer, a multi-quantum well active layer, and a P-type semiconductor hole injection layer from bottom to top; Wherein, a groove extending to the N-type semiconductor electron injection layer is provided on the upper surface of the P-type semiconductor hole injection layer, so that an exposed area is formed on the upper surface of the N-type semiconductor electron injection layer; the N-type electrode is provided on the surface of the exposed area; The P-type electrode is provided on the surface of the P-type semiconductor hole injection layer.

9. The deep ultraviolet LED according to claim 8, wherein: A circular groove extending downward to the N-type semiconductor electron injection layer is provided along the outer periphery of the upper surface of the P-type semiconductor hole injection layer, so that an annular exposed area is formed on the upper surface of the N-type semiconductor electron injection layer; Wherein, an annular N-type electrode is provided on the surface of the exposed area.

10. The deep ultraviolet LED according to any one of claims 8-9, wherein: The N-type semiconductor electron injection layer is an N-type aluminum gallium nitride layer; And / or, the P-type semiconductor hole injection layer is a P-type gallium nitride layer.

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