Preparation method of deep ultraviolet LED chip and deep ultraviolet LED chip

Abstract

The invention discloses a deep ultraviolet LED chip preparation method and a deep ultraviolet LED chip. The deep ultraviolet LED chip preparation method comprises the steps of growing an AlN buffer layer and a first AlGaN layer on a substrate; depositing a metal film on the first AlGaN layer to obtain a deep ultraviolet LED growth template; performing high-temperature rapid annealing on the deep ultraviolet LED growth template, and converting the metal film into a plurality of metal balls; performing graphical etching on the first AlGaN layer based on the graphical mask of the plurality of metal balls; the plurality of metal balls are cleaned through an acid solution, so that the top surface of the AlGaN insertion layer is exposed; forming an AlGaN transition layer on the AlGaN insertion layer through secondary epitaxy to form a substrate; and depositing a light-emitting element structure on the AlGaN transition layer. The patterned AlGaN insertion layer is arranged, so that the stress brought by the substrate and the AlN layer can be relieved, the dislocation density of the active region is reduced, and the luminous efficiency of the deep ultraviolet LED chip is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a preparation method of a deep ultraviolet LED chip and a deep ultraviolet LED chip. Background Art

[0002] Deep ultraviolet LEDs (Light Emitting Diodes) are used in various fields. Deep ultraviolet LEDs mainly use AlGaN as the main growth material and use the MOCVD epitaxial growth method to grow the required light-emitting structure.

[0003] At present, the heterostructure of deep ultraviolet LEDs is generally grown on sapphire substrates. Sapphire substrates provide a low-cost substrate for growing UV light-emitting devices. However, there is a relatively large lattice mismatch between sapphire and AlN, with a lattice mismatch rate of 14%. This leads to a large number of mismatch dislocations on the AlN / sapphire interface. The high-density dislocations will extend to the active region and even the p-type layer as the epitaxial layer grows, which will lead to serious non-radiative recombination and electron leakage, affecting the luminous efficiency of the deep ultraviolet LED chip. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art. The present invention provides a method for preparing a deep ultraviolet LED chip and a deep ultraviolet LED chip. By growing a patterned AlGaN insertion layer on the substrate AlN buffer layer, the stress caused by the sapphire substrate and the AlN layer can be effectively relieved, the dislocation caused by the growth of the AlN buffer layer can be reduced, and the luminous efficiency of the deep ultraviolet LED chip can be improved.

[0005] The present invention provides a method for preparing a deep ultraviolet LED chip, the preparation method comprising:

[0006] Growing an AlN buffer layer on the substrate, and disposing a first AlGaN layer on the AlN buffer layer;

[0007] Depositing a metal film on the first AlGaN layer to obtain a deep ultraviolet LED growth template;

[0008] Performing high-temperature rapid annealing on the deep ultraviolet LED growth template to transform the metal film into a plurality of metal spheres;

[0009] Performing patterned etching on the first AlGaN layer based on a patterned mask of a plurality of metal balls to form an AlGaN insertion layer;

[0010] Cleaning a plurality of metal balls with an acid solution so that the top surface of the AlGaN insertion layer is exposed;

[0011] Performing secondary epitaxy on the AlGaN insertion layer, so that an AlGaN transition layer is formed on the AlGaN insertion layer to form a substrate;

[0012] A light emitting element structure is deposited on the AlGaN transition layer.

[0013] Further, the growing of an AlN buffer layer on the substrate and providing a first AlGaN layer on the AlN buffer layer comprises:

[0014] The substrate is placed in a MOCVD device, the raw material output ratio of the MOCVD device is adjusted, and a first AlGaN layer with a high proportion of Al metal element components is deposited on the AlN buffer layer.

[0015] Furthermore, the step of depositing a metal film on the first AlGaN layer to obtain a deep ultraviolet LED growth template includes:

[0016] Metal material is emitted to the first AlGaN layer on the substrate through an electron beam evaporation device, and the emission power of the electron beam evaporation device is set between 8kw and 15kw, ensuring that the electron beam evaporation device outputs energy so that the metal material adheres to the surface of the first AlGaN layer and forms a metal film on the first AlGaN layer.

[0017] Furthermore, the step of rapidly annealing the deep ultraviolet LED growth template at high temperature to convert the metal film into a plurality of metal balls comprises:

[0018] In a nitrogen atmosphere, high-temperature annealing is performed on the deep ultraviolet LED growth template, so that the metal film melts and breaks under the high-temperature environment to form a plurality of molten metals;

[0019] The molten metal in some places forms a spherical shape due to surface tension, and forms a plurality of metal balls after solidification.

[0020] Furthermore, the patterning of the first AlGaN layer using a patterned mask of a plurality of metal balls to form an AlGaN insertion layer includes:

[0021] The deep ultraviolet LED growth template is ICP-etched by using chlorine gas, and the first AlGaN layer is pattern-etched by using a patterned mask formed by a plurality of metal balls to form an AlGaN insertion layer.

[0022] Furthermore, the secondary epitaxy is performed on the AlGaN insertion layer so that an AlGaN transition layer is formed on the AlGaN insertion layer, and the formation of the substrate includes:

[0023] The deep ultraviolet LED growth template is placed in a MOCVD device for secondary epitaxy, and raw materials and a nitrogen source are used to deposit AlGaN crystals on the AlGaN insertion layer under high temperature conditions to form an AlGaN transition layer.

[0024] The present invention also provides a deep ultraviolet LED chip, which is prepared by the preparation method, and the deep ultraviolet LED chip is provided with an AlGaN insertion layer, and the AlGaN insertion layer is configured as a patterned structure.

[0025] Furthermore, the Al metal element component of the AlGaN insertion layer accounts for more than 80%.

[0026] Furthermore, the thickness of the AlGaN insertion layer is h1, and the value range of h1 is: 50nm≤h1≤100nm;

[0027] The AlGaN insertion layer is provided with a plurality of grooves, the depth of any of the grooves is h2, and the value range of h2 is: 30nm≤h2≤50nm.

[0028] Furthermore, the deep ultraviolet LED chip is also provided with an AlGaN transition layer, and the Al metal element component of the AlGaN transition layer accounts for 50% to 80%.

[0029] The present invention provides a preparation method of a deep ultraviolet LED chip and a deep ultraviolet LED chip. An AlGaN insertion layer with a high Al group is grown on an AlN buffer layer of a substrate to improve the bonding performance between the AlGaN insertion layer and the AlN layer. A patterned AlGaN insertion layer is provided to effectively relieve the stress caused by the sapphire substrate and the AlN layer, reduce the dislocation caused by the growth of the AlN buffer layer, and improve the luminous efficiency of the deep ultraviolet LED chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is a flow chart of a method for preparing a deep ultraviolet LED chip in an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the preparation state of the first AlGaN layer in an embodiment of the present invention;

[0033] Figure 3is a schematic diagram of the preparation state of the metal film in an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of the preparation state of the metal ball in the embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of the preparation state of the AlGaN insertion layer in an embodiment of the present invention;

[0036] Figure 6 is a structural schematic diagram of the preparation state of the AlGaN insertion layer in an embodiment of the present invention;

[0037] Figure 7 Schematic diagram of the substrate structure of the deep ultraviolet LED chip in the embodiment of the present invention;

[0038] Figure 8 Schematic diagram of the structure of the deep ultraviolet LED chip in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Embodiment 1:

[0041] Figure 1 The flowchart of the preparation method of the deep ultraviolet LED chip in the embodiment of the present invention is shown, and the preparation method comprises:

[0042] S11 : growing an AlN buffer layer 2 on the substrate 1 , and providing a first AlGaN layer 3 on the AlN buffer layer 2 .

[0043] Specifically, Figure 2 A schematic diagram of the preparation state of the first AlGaN layer 3 in an embodiment of the present invention is shown, an AlN buffer layer 2 is grown on a substrate 1, and an AlGaN layer is arranged on the AlN buffer layer 2, a sapphire substrate 1 is selected, and the sapphire substrate 1 is cleaned to remove surface dirt of the sapphire substrate 1, thereby improving the preparation quality of the AlN buffer layer 2 on the sapphire substrate 1.

[0044] The material of the substrate 1 can also be sapphire, silicon carbide (SiC), silicon (Si), etc. The sapphire substrate 1 has good thermal stability and chemical stability, and can meet the preparation requirements of the deep ultraviolet LED chip.

[0045] Check and debug the MOCVD equipment to ensure that it is in good working condition, place the substrate 1 in the reaction chamber of the MOCVD equipment, and heat it to an appropriate temperature to remove adsorbed water and gas on the surface of the substrate 1, introduce appropriate amounts of Al metal element and N element raw materials, adjust the pressure and temperature of the reaction chamber, and grow an AlN buffer layer 2 on the substrate 1.

[0046] During the growth process, parameters such as the flow rate of the source material, the pressure and temperature of the reaction chamber need to be precisely controlled to obtain a high-quality AlN buffer layer 2. After the AlN buffer layer 2 is grown, the AlN buffer layer 2 is annealed to further improve its crystal quality and stability.

[0047] Specifically, according to the composition and performance requirements of the first AlGaN layer 3, the flow ratio of TMAl, TMGa and NH3, as well as the pressure and temperature of the reaction chamber are adjusted to grow the AlGaN layer on the AlN buffer layer 2. The first AlGaN layer 3 can be formed on the AlN buffer layer 2 by controlling the flow of various raw materials in the MOCVD equipment as well as the working pressure and reaction temperature of the MOCVD equipment.

[0048] During the growth process, parameters can be adjusted through real-time monitoring and feedback to ensure that the composition and thickness of the AlGaN layer meet the design requirements.

[0049] Furthermore, the output ratio and delivery rate of the TMAl raw material are adjusted in the MOCVD device so that the first AlGaN layer 3 containing a high component Al metal element can be deposited on the AlN buffer layer 2. The first AlGaN layer 3 with a high Al component can better connect with the AlN buffer layer 2 and reduce the lattice mismatch caused by component mutation.

[0050] Furthermore, the Al metal element content of the first AlGaN layer 3 is greater than 80%, thereby effectively improving the bonding performance between the first AlGaN layer 3 and the AlN buffer layer 2 .

[0051] S12: depositing a metal film 4 on the first AlGaN layer 3 to obtain a deep ultraviolet LED growth template;

[0052] Specifically, Figure 3A schematic diagram of the preparation state of the metal film 4 in an embodiment of the present invention is shown. The metal film 4 is deposited on the top surface of the first AlGaN layer 3 by electron beam evaporation. The thickness of the metal film 4 is H, and the value range of H is: 1mm≤H≤10mm. By preparing the metal film 4 on the first AlGaN layer 3, the metal film 4 can meet the coverage of the AlGaN layer. After high-temperature annealing treatment, the metal film 4 can form a plurality of metal balls 41 on the first AlGaN layer 3 to meet the demand for graphical processing of the first AlGaN layer 3. By reducing the thickness of the metal film 4, the reaction time of the metal film 4 can be shortened, thereby reducing the preparation time of the deep ultraviolet LED and improving the preparation efficiency of the deep ultraviolet LED chip.

[0053] Metal material is emitted to the first AlGaN layer 3 on the substrate 1 through an electron beam evaporation device, and the emission power of the electron beam evaporation device is set between 8kw and 15kw to ensure that the electron beam evaporation device outputs sufficient energy to satisfy the requirement that the metal material adheres to the surface of the first AlGaN layer 3, so that the metal material can be deposited to form a metal film 4.

[0054] Furthermore, by configuring the emission frequency and output energy stability of the electron beam evaporation device, the surface of the first AlGaN layer 3 can be evenly covered with metal material, thereby forming the metal thin layer.

[0055] Furthermore, the metal material may be one of gold (Au) or copper (Cu). The Au metal and the Cu metal have the characteristics of low melting points, which can improve the convenience of depositing the metal film 4 on the first AlGaN layer 3.

[0056] S13 : performing high-temperature rapid annealing on the deep ultraviolet LED growth template to transform the metal film 4 into a plurality of metal balls 41 .

[0057] Specifically, Figure 4 A schematic diagram of the preparation state of the metal ball 41 in an embodiment of the present invention is shown. In a nitrogen atmosphere, the ambient temperature of the deep ultraviolet LED growth template is heated to above 800°C, and the annealing time is set to above 2 minutes, so that the metal film 4 melts and breaks in a high temperature environment, thereby causing the metal film 4 to break and form several molten metals. Based on the surface tension of the molten metals at several locations, the molten metals at several locations can form spherical shapes. After solidification, the spherical molten metals can solidify to form metal balls 41.

[0058] Furthermore, based on the metal balls 41 formed by the solidification of the molten metal at several locations, a plurality of dispersed metal balls 41 are formed on the surface of the first AlGaN layer 3, so that the first AlGaN layer 3 is partially exposed in the gaps formed between the metal balls 41, that is, a patterned mask can be formed on the surface of the first AlGaN layer 3 based on the plurality of metal balls 41.

[0059] Specifically, in an embodiment of the present invention, the deep ultraviolet LED growth template is placed in an annealing furnace, and nitrogen is continuously input into the box of the annealing furnace. After a first gas supply time, the annealing furnace is heated so that the internal temperature of the box of the annealing furnace reaches above 800°C.

[0060] Furthermore, the first gas supply time is 20 seconds, and nitrogen is continuously supplied into the box of the annealing furnace, so that the air inside the annealing furnace is exhausted and the box of the annealing furnace is filled with nitrogen.

[0061] After nitrogen is continuously input into the box for 20 seconds, the annealing furnace is heated by a heating device. Based on the temperature sensor in the annealing furnace, it is ensured that the internal temperature of the annealing furnace box can reach above 800°C. The annealing time is set to more than 5 minutes, so that the several metal balls 41 formed by the metal film 4 are formed and the internal stress of the metal balls 41 is reduced to ensure the reliability of subsequent processing.

[0062] S14 : performing patterned etching on the first AlGaN layer 3 based on the patterned mask of a plurality of metal balls 41 to form an AlGaN insertion layer 5 .

[0063] Specifically, Figure 5 A schematic diagram of the preparation state of the AlGaN insertion layer 5 in an embodiment of the present invention is shown. The deep ultraviolet LED growth template is ICP etched using chlorine gas, and the first AlGaN layer 3 is patterned etched using a patterned mask formed by a plurality of metal balls 41 to form the AlGaN insertion layer 5.

[0064] Specifically, chlorine gas is delivered to the deep ultraviolet LED growth template and introduced into the ICP etching system as a key reaction gas. The chlorine gas interacts with high-energy electrons and ions in the plasma, that is, the chlorine gas can chemically etch with the aluminum and gallium elements in the first AlGaN layer 3 to form volatile compounds, thereby effectively removing the first AlGaN layer 3. The etching depth of the first AlGaN layer 3 can also be controlled by precisely controlling the reaction rate and reaction time, thereby achieving high-precision material removal.

[0065] Furthermore, based on the patterned mask formed by the plurality of metal balls 41 , the contact position between the chlorine gas and the first AlGaN layer 3 during the ICP etching process can be adjusted to meet the requirements of the patterned etching of the first AlGaN layer 3 .

[0066] Specifically, the thickness of the AlGaN insertion layer 5 is h1, and the value range of h1 is: 50nm≤h1≤100nm. The etching depth of the first AlGaN layer 3 by the ICP etching is h2, and the value range of h2 is: 30nm≤h2≤50nm. Based on ICP etching, a plurality of grooves are formed on the first AlGaN layer 3, thereby improving the crystal quality of the epitaxial layer.

[0067] Furthermore, the ICP etching uses gas glow discharge to generate plasma, and realizes the material removal operation through the dual effects of chemistry and physics. Under vacuum and low pressure, the radio frequency generated by the ICP radio frequency power supply is output to the annular coupling coil, and a certain proportion of mixed etching gas is coupled to glow discharge to generate high-density plasma (including ions, electrons, active particles, photons and excited atoms). The power directly affects the ionization rate of the plasma, thereby affecting the density of the plasma. Under the RF radio frequency of the lower electrode, these heavy ions physically bombard the surface of the chip, and at the same time, the active particles react chemically with the material in the graphic area to generate volatile substances, which are separated from the chip in the form of gas and are extracted from the vacuum pipeline, thereby realizing the material etching operation of the first AlGaN layer 3, and the graphic mask formed by the plurality of metal balls 41 can meet the graphic etching processing requirements of the first AlGaN layer 3, thereby converting the first AlGaN layer 3 into an AlGaN insertion layer 5.

[0068] S15: cleaning the plurality of metal balls 41 with an acid solution, so that the top surface of the AlGaN insertion layer 5 is exposed.

[0069] Specifically, Figure 6 A structural schematic diagram of the preparation state of the AlGaN insertion layer 5 in an embodiment of the present invention is shown. The metal balls 41 on the top surface of the AlGaN insertion layer 5 are cleaned by an acidic solution so that the top surface of the AlGaN insertion layer 5 is completely exposed to the outside, so that a semiconductor chip structure can be prepared on the AlGaN insertion layer 5.

[0070] Furthermore, the acidic solution may be nitrohydrochloric acid, which is a highly corrosive liquid formed by mixing concentrated hydrochloric acid (HCl) and concentrated nitric acid (HNO 3 ) in a certain proportion, and can corrode and eliminate the metal balls 41 .

[0071] Place the deep ultraviolet LED growth template with the AlGaN insertion layer 5 in a container, and add an appropriate amount of nitrohydrochloric acid into the container to ensure that the nitrohydrochloric acid can fully contact the metal balls 41 of the AlGaN insertion layer 5, so that the nitrohydrochloric acid can corrode and ablate the metal balls 41, thereby achieving the elimination of the metal balls 41 of the AlGaN insertion layer 5.

[0072] Furthermore, the best removal effect can be obtained by controlling the treatment time of the nitrohydrochloric acid and the working temperature of the nitrohydrochloric acid in the container.

[0073] Furthermore, after the elimination treatment of the metal balls 41 of the AlGaN insertion layer 5 is completed, the surface of the AlGaN insertion layer 5 is cleaned with deionized water or other appropriate cleaning agents to remove residual nitrohydrochloric acid solution and metal chlorides, and the cleaned deep ultraviolet LED growth template is placed in a dry environment or dried using drying equipment so as to perform subsequent process steps on the AlGaN insertion layer 5.

[0074] S16: performing secondary epitaxy on the AlGaN insertion layer 5 , so as to form an AlGaN transition layer 6 on the AlGaN insertion layer 5 , thereby forming a substrate.

[0075] Specifically, Figure 7 A schematic diagram of the substrate structure of the deep ultraviolet LED chip in an embodiment of the present invention is shown. The deep ultraviolet LED growth template is placed in an MOCVD device for secondary epitaxy. After the raw materials and the nitrogen source are fully mixed in the reaction chamber, a cracking reaction occurs to generate reaction precursors and by-products. These precursors are deposited on the surface of the AlGaN insertion layer 5 and react with the nitrogen source reaching the substrate 1 at high temperature to generate AlGaN crystals.

[0076] Furthermore, the AlGaN insertion layer 5 is a graphic structure, based on the gas phase particles in the MOCVD device adhering to the surface of the AlGaN insertion layer 5 and reacting with the nitrogen source provided by the MOCVD device, the surface of the AlGaN insertion layer 5 can grow AlGaN crystals, and the bottom of the groove of the AlGaN insertion layer 5 and the top surface of the AlGaN insertion layer 5 simultaneously grow AlGaN crystals, so that an AlGaN transition layer 6 is formed on the surface of the AlGaN insertion layer 5, and the junction position between the AlGaN insertion layer 5 and the AlGaN transition layer 6 is based on the graphic structure of the AlGaN insertion layer 5, which can effectively alleviate the stress brought by the substrate and the AlN buffer layer, thereby reducing the dislocations brought by the growth of the AlN buffer layer 2.

[0077] MOCVD (Metal Organic Chemical Vapor Deposition) is metal organic chemical vapor deposition, a new type of vapor phase epitaxial growth technology, which uses metal organic compounds and hydrides as source materials for crystal growth, and performs vapor phase epitaxy on substrate 1 through thermal decomposition reaction to grow various III-V group, II-VI group compound semiconductors and their multi-component solid solution thin layer single crystal materials.

[0078] Furthermore, by depositing the AlGaN transition layer 6 on the AlGaN insertion layer 5 , the substrate 1 , the AlN layer, the AlGaN insertion layer 5 and the AlGaN transition layer 6 cooperate to form a base structure, thereby meeting the structural preparation requirements of deep ultraviolet LED devices.

[0079] S17 : depositing the light emitting element structure 7 on the AlGaN transition layer 6 .

[0080] Figure 8 A schematic structural diagram of a deep ultraviolet LED chip in an embodiment of the present invention is shown. Specifically, an n-AlGaN layer 71, a multiple quantum well light-emitting layer 72, a final barrier layer, a p-AlGaN electron blocking layer 73, and a p-AlGaN hole injection layer 74 are sequentially deposited on the AlGaN transition layer 6 by a MOVCD device, thereby forming a light-emitting element structure 7 of the deep ultraviolet LED.

[0081] The n-AlGaN layer 71 serves as the bottom layer of the semiconductor light-emitting element, and the thickness of the n-AlGaN layer 71 is h3, and the value range of h3 is 2μm≤h3≤3μm, which can meet the requirements for preparing the light-emitting structure of the deep ultraviolet LED.

[0082] The n-AlGaN layer 71 is epitaxially grown on the substrate 1 by using methods such as metal organic chemical vapor deposition (MOCVD), and high-quality n-AlGaN layer 71 is obtained by precisely controlling growth conditions such as temperature, pressure, gas flow, etc.

[0083] Furthermore, in this embodiment, the deep ultraviolet LED growth template is placed in a MOCVD device, and by adjusting the gas source raw material of the MOCVD device and setting the working temperature of the MOCVD to 900°C to 1300°C, the vapor deposition environment inside the MOCVD device is set to a certain pressure state, and the metal organic matter can be uniformly deposited on the surface of the AlGaN transition layer 6 to form the n-AlGaN layer 71.

[0084] Appropriate AlGaN components and dopants are selected to perform n-type doping, and an n-AlGaN layer 71 is grown on the AlGaN transition layer 6 by using methods such as MOCVD.

[0085] Specifically, the multi-quantum well light-emitting layer 72 is the core part of the semiconductor light-emitting element, and is usually composed of multiple periods of well layers and barrier layers. Taking a 2.5nm well layer and a 10nm barrier layer as an example, the preparation process is as follows:

[0086] Well layer growth: A well layer with a thickness of 2 to 5 nm is grown on the n-AlGaN layer 71. The well layer may be an AlInGaN layer or an AlGaN layer. The growth conditions are precisely controlled to obtain uniform well layer thickness and composition.

[0087] Barrier layer growth: Select appropriate AlGaN components and dopants, perform n-type doping, and grow an 8-15nm thick AlGaN barrier layer on the well layer. The function of the barrier layer is to confine carriers in the well layer and improve the luminous efficiency.

[0088] Repeated growth: The growth process of the well layer and barrier layer is repeated many times to form a multiple quantum well structure. The thickness and composition of the well layer and barrier layer in each cycle can be adjusted as needed.

[0089] Furthermore, the last barrier layer is usually located on the multi-quantum well light-emitting layer 72 to further confine carriers and protect the quantum well structure.

[0090] Specifically, the p-AlGaN electron blocking layer 73 is used to prevent electrons from escaping from the quantum well to the p-type layer, thereby improving the luminous efficiency. Select appropriate AlGaN components and dopants, such as Mg, etc., for p-type doping, and grow the p-AlGaN electron blocking layer 73 on the final barrier layer using methods such as MOCVD. The thickness of the p-AlGaN electron blocking layer 73 is h4, and the value range of h4 is: 10nm≤h4≤30nm, so that the p-AlGaN electron blocking layer 73 can meet the light output requirements of deep ultraviolet LEDs.

[0091] Specifically, the p-AlGaN hole injection layer 74 is located on the electron blocking layer 73 to provide holes. The preparation process of the p-AlGaN hole injection layer 74 is similar to that of the p-AlGaN electron blocking layer 73. The preparation method of the p-AlGaN electron blocking layer 73 mentioned above can be referred to and will not be described in detail here.

[0092] Furthermore, the thickness of the p-AlGaN hole injection layer 74 is h5, and the value range of h5 is 50nm≤h5≤100nm. By precisely controlling the growth conditions and dopant concentration, a high-quality p-AlGaN hole injection layer 74 can be obtained, thereby meeting the preparation requirements of the deep ultraviolet LED light-emitting element structure 7.

[0093] The embodiment of the present invention provides a method for preparing a deep ultraviolet LED chip, by growing an AlGaN insertion layer 5 with a high Al group on an AlN buffer layer 2 of a substrate 1, thereby improving the bonding performance between the AlGaN insertion layer 5 and the AlN layer. By setting a patterned AlGaN insertion layer 5, the stress caused by the sapphire substrate 1 and the AlN layer can be effectively alleviated, the dislocation caused by the growth of the AlN buffer layer 2 can be reduced, and the luminous efficiency of the deep ultraviolet LED chip can be improved.

[0094] Embodiment 2:

[0095] Please refer to Figure 8 The deep ultraviolet LED chip is prepared by the preparation method, and the deep ultraviolet LED chip is provided with an AlGaN insertion layer 5, and the AlGaN insertion layer 5 is configured as a patterned structure.

[0096] The deep ultraviolet LED chip is sequentially configured with a substrate 1, an AlN buffer layer 2, an AlGaN insertion layer 5, an AlGaN transition layer 6, and a light-emitting element structure 7 from bottom to top. By configuring the AlGaN insertion layer 5 as a patterned structure, the stress caused by the sapphire substrate 1 and the AlN layer can be effectively alleviated, the dislocation caused by the growth of the AlN buffer layer 2 can be reduced, and the luminous efficiency of the deep ultraviolet LED chip can be improved.

[0097] The light emitting element structure 7 includes an n-AlGaN layer 71, a multiple quantum well light emitting layer 72, a final barrier layer, a p-AlGaN electron blocking layer 73 and a p-AlGaN hole injection layer 74, which can achieve the light emission effect of the deep ultraviolet LED chip.

[0098] Furthermore, the Al metal element component of the AlGaN insertion layer 5 accounts for more than 80%, thereby effectively improving the bonding performance between the AlGaN insertion layer 5 and the AlN buffer layer 2, improving the connection stability between the AlGaN insertion layer 5 and the AlN buffer layer 2, and reducing the stress caused by growing the AlN buffer layer 2.

[0099] Furthermore, the AlGaN insertion layer 5 is provided with a plurality of grooves, the depth of any of the grooves is h2, and the value range of h2 is: 30nm≤h2≤50nm, so that when the AlGaN transition layer 6 is deposited on the AlGaN insertion layer 5, the stress brought by the sapphire substrate 1 and the AlN layer can be effectively alleviated, the dislocation caused by the growth of the AlN buffer layer 2 can be reduced, and the luminous efficiency of the deep ultraviolet LED chip can be improved.

[0100] Furthermore, the deep ultraviolet LED chip is also provided with an AlGaN transition layer 6 , and the Al metal element component of the AlGaN transition layer 6 accounts for 50% to 80%, meeting the preparation requirements of the AlGaN transition layer 6 for deposition of the light-emitting element structure 7 .

[0101] An embodiment of the present invention provides a deep ultraviolet LED chip, which improves the bonding performance between the AlGaN insertion layer 5 and the AlN layer by growing an AlGaN insertion layer 5 with a high Al group on the AlN buffer layer 2 of the substrate 1. By setting a patterned AlGaN insertion layer 5, the stress brought by the sapphire substrate 1 and the AlN layer can be effectively alleviated, the dislocation caused by the growth of the AlN buffer layer 2 can be reduced, and the luminous efficiency of the deep ultraviolet LED chip can be improved.

[0102] A person skilled in the art may understand that all or part of the steps in the various methods of the above embodiments may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the storage medium may include: a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc.

[0103] In addition, the embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for preparing a deep ultraviolet LED chip, characterized in that: The preparation method comprises: Growing an AlN buffer layer on the substrate, and disposing a first AlGaN layer on the AlN buffer layer; Depositing a metal film on the first AlGaN layer to obtain a deep ultraviolet LED growth template; Performing high-temperature rapid annealing on the deep ultraviolet LED growth template to transform the metal film into a plurality of metal spheres; Performing patterned etching on the first AlGaN layer based on a patterned mask of a plurality of metal balls to form an AlGaN insertion layer; Cleaning a plurality of metal balls with an acid solution so that the top surface of the AlGaN insertion layer is exposed; Performing secondary epitaxy on the AlGaN insertion layer, so that an AlGaN transition layer is formed on the AlGaN insertion layer to form a substrate; A light emitting element structure is deposited on the AlGaN transition layer.

2. The method for preparing a deep ultraviolet LED chip according to claim 1, characterized in that: The step of growing an AlN buffer layer on a substrate and providing a first AlGaN layer on the AlN buffer layer comprises: The substrate is placed in a MOCVD device, the raw material output ratio of the MOCVD device is adjusted, and a first AlGaN layer with a high proportion of Al metal element components is deposited on the AlN buffer layer.

3. The method for preparing a deep ultraviolet LED chip according to claim 1, characterized in that: The step of depositing a metal film on the first AlGaN layer to obtain a deep ultraviolet LED growth template comprises: Metal material is emitted to the first AlGaN layer on the substrate through an electron beam evaporation device, and the emission power of the electron beam evaporation device is set between 8kw and 15kw, ensuring that the electron beam evaporation device outputs energy so that the metal material adheres to the surface of the first AlGaN layer and forms a metal film on the first AlGaN layer.

4. The method for preparing a deep ultraviolet LED chip according to claim 1, characterized in that: The step of rapidly annealing the deep ultraviolet LED growth template at high temperature to convert the metal film into a plurality of metal balls comprises: In a nitrogen atmosphere, the deep ultraviolet LED growth template is subjected to high-temperature annealing, so that the metal film is broken at high temperature and forms a molten state, and a plurality of metal balls are formed based on the effect of surface tension.

5. The method for preparing a deep ultraviolet LED chip according to claim 1, characterized in that: The step of patterning the first AlGaN layer using a patterned mask based on a plurality of metal balls to form an AlGaN insertion layer comprises: The deep ultraviolet LED growth template is ICP-etched by using chlorine gas, and the first AlGaN layer is pattern-etched by using a patterned mask formed by a plurality of metal balls to form an AlGaN insertion layer.

6. The method for preparing a deep ultraviolet LED chip according to claim 1, characterized in that: The step of performing secondary epitaxy on the AlGaN insertion layer so as to form an AlGaN transition layer on the AlGaN insertion layer, and forming a substrate comprises: The deep ultraviolet LED growth template is placed in a MOCVD device for secondary epitaxy, and raw materials and a nitrogen source are used to deposit AlGaN crystals on the AlGaN insertion layer under high temperature conditions to form an AlGaN transition layer.

7. A deep ultraviolet LED chip, characterized in that: The deep ultraviolet LED chip is prepared by the preparation method according to any one of claims 1 to 6, and the deep ultraviolet LED chip is provided with an AlGaN insertion layer, and the AlGaN insertion layer is configured as a patterned structure.

8. The deep ultraviolet LED chip according to claim 7, characterized in that: The Al metal element component of the AlGaN insertion layer accounts for more than 80%.

9. The deep ultraviolet LED chip according to claim 7, characterized in that: The thickness of the AlGaN insertion layer is h1, and the value range of h1 is: 50nm≤h1≤100nm; The AlGaN insertion layer is provided with a plurality of grooves, the depth of any of the grooves is h2, and the value range of h2 is: 30nm≤h2≤50nm.

10. The deep ultraviolet LED chip according to claim 7, characterized in that: The deep ultraviolet LED chip is also provided with an AlGaN transition layer, and the Al metal element component of the AlGaN transition layer accounts for between 50% and 80%.

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