Deep ultraviolet led chip and method of manufacturing the same

Abstract

This disclosure provides a deep ultraviolet (DUV) LED chip and its fabrication method. The DUV LED chip includes: a substrate, an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type ohmic contact electrode stacked sequentially. In this configuration, a portion of the n-type AlGaN layer is not covered by the p-type AlGaN layer, electron blocking layer, and active region, exposing the n-type AlGaN layer. A portion of the exposed n-type AlGaN layer is removed to form a mesa structure. An n-type semiconductor layer and an n-type ohmic contact electrode are formed on the exposed portion of the n-type AlGaN layer. The n-type semiconductor layer serves as both the n-type ohmic contact layer and the electron supply layer. The sidewalls of the mesa structure are covered with a passivation layer.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor optoelectronic devices, and in particular to a deep ultraviolet LED chip and its fabrication method. Background Technology

[0002] AlGaN-based semiconductor materials have become the core material for LED devices in the ultraviolet to blue light bands due to their excellent properties such as adjustable bandgap (0.7-6.2eV), high luminous efficiency, and good thermal stability. They are widely used in lighting displays, sterilization and disinfection, biochemical detection and other fields.

[0003] In the preparation of high-Al content AlGaN materials, n-type doping faces insurmountable technical obstacles. Among related technologies, Si is the most commonly used n-type dopant for AlGaN-based UVC LEDs. However, with increasing Al content, the ionization energy of Si donors increases dramatically. When the Al content exceeds 80%, the Si ionization energy can reach 250 meV, far exceeding the room temperature thermal activation energy (approximately 26 meV), making it difficult for Si atoms to effectively ionize and form free electrons. Simultaneously, the self-compensation effect under high Al content further exacerbates the doping dilemma. When doped with low concentrations of Si, impurities merge with intrinsic vacancies to form compensation centers; when doped with high concentrations of Si, Al vacancies readily form stable complexes with Si. Both mechanisms prevent an effective increase in free carrier concentration, making it difficult to achieve ideal conductivity even with high doping concentrations.

[0004] The aforementioned challenges of n-type doping directly trigger a series of cascading problems. The low conductivity and high Al composition of n-AlGaN makes it difficult to form low-resistance ohmic contacts, leading to a significant increase in device operating voltage and exacerbating heat accumulation. The combination of low carrier concentration and high contact resistance results in uneven current distribution, causing current congestion and accelerating device performance degradation.

[0005] To address the n-type doping problem in high-Al-content AlGaN, various technical solutions have been explored. For example, chemical potential control can be used to regulate the growth environment and suppress the compensation effect; however, this method requires extremely high precision in controlling growth parameters and has a narrow process window. Modulation doping techniques using alternating Si-doped / undoped layers can improve material quality and carrier mobility, but fail to fundamentally improve activation efficiency. Short-period superlattice doping of AlGaN can reduce the activation energy of Si and increase electron concentration, but results in high longitudinal resistivity. SF6 plasma treatment of the n-AlGaN surface can reduce contact resistivity, but its improvement on contact characteristics for AlGaN with higher Al content is limited. None of these solutions simultaneously achieve the goals of high activation concentration, high conductivity, and process compatibility, making it difficult to meet the application requirements of high-efficiency deep ultraviolet LEDs. Summary of the Invention

[0006] In view of this, the present disclosure provides a deep ultraviolet LED chip and a method for fabricating the same, which at least partially solves the above-mentioned technical problems.

[0007] One embodiment of this disclosure provides a deep ultraviolet LED chip, comprising: a substrate, an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type ohmic contact electrode stacked sequentially; wherein, a portion of the n-type AlGaN layer is not formed above the p-type AlGaN layer, the electron blocking layer, and the active region, exposing the n-type AlGaN layer, and a portion of the exposed n-type AlGaN layer is removed to form a mesa structure; an n-type semiconductor layer and an n-type ohmic contact electrode are formed on the exposed portion of the n-type AlGaN layer, the n-type semiconductor layer serving as the n-type ohmic contact layer and the electron supply layer, and the sidewalls of the mesa structure are covered with a passivation layer.

[0008] According to embodiments of this disclosure, the n-type semiconductor layer includes an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, and an n-type Si semiconductor layer; the conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

[0009] According to embodiments of this disclosure, a low-Al composition p-type Al layer is further formed between the p-type AlGaN layer and the p-type ohmic contact electrode. x Ga 1-x The system consists of N layers, where 0 ≤ x ≤ 0.4; a hole blocking layer is also provided between the n-type AlGaN and the active region; and a transition layer is also formed between the AlN template layer and the n-type AlGaN layer.

[0010] According to embodiments of this disclosure, the passivation layer is a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide and aluminum nitride, or a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride and a dielectric layer.

[0011] Another aspect of this disclosure provides a method for fabricating a deep ultraviolet (DUV) LED chip, comprising: providing a substrate, and sequentially fabricating an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer on the substrate to obtain a DUV LED epitaxial wafer; removing the p-type GaN layer, p-type AlGaN layer, electron blocking layer, active region, and a portion of the n-type AlGaN layer in a designated area to form a mesa structure, thereby exposing a portion of the surface of the n-type AlGaN layer; and fabricating a deep ultraviolet LED epitaxial wafer on the substrate. A mask layer is deposited on the surface and patterned to form a mask layer window, allowing the exposed n-type AlGaN layer surface to remain exposed. A high-conductivity n-type semiconductor layer is deposited on the surface of the deep ultraviolet LED epitaxial wafer. The mask layer and the high-conductivity n-type semiconductor layer attached thereon are removed. A passivation layer is deposited on the surface of the deep ultraviolet LED epitaxial wafer. The passivation layers on the surface of the high-conductivity n-type semiconductor layer and the p-type GaN layer are removed respectively, and n-type ohmic contact electrodes and p-type ohmic contact electrodes are deposited respectively to obtain the deep ultraviolet LED chip.

[0012] Another aspect of this disclosure provides a deep ultraviolet LED chip, comprising: a conductive substrate, a p-type ohmic contact electrode, a p-type AlGaN layer, an electron blocking layer, a multi-quantum well active region, an n-type AlGaN layer, an n-type semiconductor layer, and an n-type ohmic contact electrode stacked sequentially; wherein the n-type semiconductor layer is used for the n-type ohmic contact layer and the electron supply layer.

[0013] According to embodiments of this disclosure, the n-type semiconductor layer includes an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, and an n-type Si semiconductor layer; the conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

[0014] According to embodiments of this disclosure, the n-type semiconductor layer is opaque to the emission wavelength of the deep ultraviolet LED chip, and the n-type semiconductor layer and the n-type ohmic contact electrode partially cover the surface of the n-type AlGaN layer.

[0015] According to embodiments of this disclosure, the n-type semiconductor layer is transparent to the emission wavelength of the deep ultraviolet LED chip, the n-type semiconductor layer covers the surface of the n-type AlGaN layer, and the n-type ohmic contact electrode portion covers the surface of the n-type AlGaN layer.

[0016] Another aspect of this disclosure provides a method for fabricating a deep ultraviolet (DUV) LED chip, comprising: providing a substrate; sequentially fabricating an AlN template layer, an n-type AlGaN layer, a multiple quantum well active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer on the substrate to obtain a DUV LED epitaxial wafer; depositing a p-type ohmic contact electrode on the surface of the p-type GaN layer of the DUV LED epitaxial wafer; bonding the p-type ohmic contact electrode to a conductive substrate; sequentially removing the substrate and the AlN template layer of the DUV LED epitaxial wafer to expose the n-type AlGaN layer; depositing an n-type semiconductor layer on the surface of the n-type AlGaN layer; and depositing an n-type ohmic contact electrode on the surface of the n-type semiconductor layer to obtain a DUV LED chip.

[0017] The deep ultraviolet LED chip and its fabrication method disclosed herein have at least the following technical effects: the high-conductivity n-type semiconductor layer deposited on the high-Al composition n-AlGaN layer of the deep ultraviolet LED chip serves as an n-type ohmic contact layer and an electron supply layer, which can effectively reduce the operating voltage of the device and improve the carrier injection efficiency and luminous efficiency. Attached Figure Description

[0018] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0019] Figure 1 The schematic diagram illustrates a cross-sectional structure of a deep ultraviolet LED chip according to an embodiment of the present disclosure.

[0020] Figure 2 A cross-sectional structure of a deep ultraviolet LED chip according to another embodiment of the present disclosure is illustrated schematically.

[0021] Figure 3 The schematic diagram illustrates a cross-sectional structure of a deep ultraviolet LED chip according to yet another embodiment of the present disclosure.

[0022] Figure 4 A flowchart illustrating a method for fabricating a deep ultraviolet LED chip according to an embodiment of the present disclosure is shown.

[0023] Figure 5 A flowchart illustrating a method for fabricating a deep ultraviolet LED chip according to another embodiment of the present disclosure is shown. Detailed Implementation

[0024] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0025] Figure 1 The schematic diagram illustrates a cross-sectional structure of a deep ultraviolet LED chip according to an embodiment of the present disclosure.

[0026] like Figure 1 As shown, a deep ultraviolet LED chip may include a substrate, an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type ohmic contact electrode stacked sequentially.

[0027] In this structure, a portion of the n-type AlGaN layer is not covered by a p-type AlGaN layer, an electron blocking layer, or an active region, thus exposing the n-type AlGaN layer. The exposed portion of the n-type AlGaN layer is partially removed to form a mesa structure. An n-type semiconductor layer and an n-type ohmic contact electrode are formed on the exposed portion of the n-type AlGaN layer. The n-type semiconductor layer serves as the n-type ohmic contact layer and the electron supply layer. The sidewalls of the mesa structure are covered with a passivation layer.

[0028] The active region can be designed according to requirements, using multi-quantum-well structures or single-well thick-layer structures, etc.

[0029] In some embodiments, the n-type semiconductor layer may include an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, an n-type Si semiconductor layer, or other semiconductor layers that are easy to form ohmic contacts. The conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

[0030] When the high-conductivity n-type semiconductor layer is an n-type GaN-based semiconductor layer (including GaN, InN, AlN, and their ternary and quaternary alloys), its donor doping concentration is preferably higher than 1×10⁻⁶. 18 cm -3 The preferred thickness is 0.5 nm-10 μm.

[0031] When the high-conductivity n-type semiconductor layer is an n-type oxide semiconductor layer, the material can be selected from wide-bandgap materials such as indium tin oxide, gallium oxide-based materials (including gallium oxide, indium oxide, aluminum oxide, and their ternary and quaternary alloys), zinc oxide, and magnesium zinc oxide. In particular, when using an n-type gallium oxide-based semiconductor layer, its composition can be tuned to make the layer nearly transparent to the emission wavelength of deep ultraviolet LEDs; further, by using a high-reflectivity Al-based n-type ohmic contact electrode, photon absorption is reduced and photon extraction efficiency is improved.

[0032] When the high-conductivity n-type semiconductor layer is an n-type Si layer, it has both good electrical conductivity and deep ultraviolet light reflection capability, which can comprehensively improve electrical performance and light extraction efficiency.

[0033] In some embodiments, a low-Al composition p-type Al layer is also formed between the p-type AlGaN layer and the p-type ohmic contact electrode. x Ga 1-x N layers, where 0 ≤ x ≤ 0.4. Low Al component p-type Al x Ga 1-x The N-layer can be used to improve the ohmic contact characteristics on the p-side.

[0034] In some embodiments, a hole blocking layer is further disposed between the n-type AlGaN and the active region to suppress hole leakage to the n-side. The Al composition of this hole blocking layer should be higher than that of the n-type AlGaN layer.

[0035] In some embodiments, a transition layer is formed between the AlN template layer and the n-type AlGaN layer. The transition layer is used to alleviate lattice mismatch. The transition layer may include a superlattice structure or an Al composition gradient layer, etc.

[0036] In some embodiments, the passivation layer is a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide, and aluminum nitride, or a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, and a dielectric layer. The dielectric layer may include a high-refractive-index dielectric layer such as standium pentoxide, hafnium oxide, or zirconium oxide. When the passivation layer is a stacked structure, the thickness of each layer is one-quarter of its optical wavelength, thereby providing good reflectivity for the emission wavelength of the deep ultraviolet LED chip.

[0037] Figure 2 A cross-sectional structure of a deep ultraviolet LED chip according to another embodiment of the present disclosure is illustrated schematically. Figure 3 The schematic diagram illustrates a cross-sectional structure of a deep ultraviolet LED chip according to yet another embodiment of the present disclosure.

[0038] like Figure 2 and Figure 3As shown, a deep ultraviolet LED chip may include a conductive substrate, a p-type ohmic contact electrode, a p-type AlGaN layer, an electron blocking layer, a multi-quantum well active region, an n-type AlGaN layer, an n-type semiconductor layer, and an n-type ohmic contact electrode stacked sequentially.

[0039] In some embodiments, the n-type semiconductor layer may include an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, an n-type Si semiconductor layer, or other semiconductor layers that are easy to form ohmic contacts. The conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

[0040] When a high-conductivity n-type semiconductor layer is opaque to the emission wavelength of a deep ultraviolet LED, such as Figure 2 As shown, the high-conductivity n-type semiconductor layer and n-type ohmic contact electrode only cover part of the surface of the n-type AlGaN layer to reduce light emission obstruction.

[0041] When the high-conductivity n-type semiconductor layer is transparent to the emission wavelength of the deep ultraviolet LED, optionally, as... Figure 3 As shown, the high-conductivity n-type semiconductor layer completely covers the surface of the n-type AlGaN layer to alleviate the current congestion effect. Optionally, the n-type ohmic contact electrode only covers part of the surface of the high-conductivity n-type semiconductor layer to reduce light emission obstruction.

[0042] Figure 4 A flowchart illustrating a method for fabricating a deep ultraviolet LED chip according to an embodiment of the present disclosure is shown.

[0043] like Figure 4 As shown, the method for fabricating a deep ultraviolet LED chip in this embodiment may include the following steps.

[0044] Step 1: As Figure 4 As shown in Figure a, an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer are sequentially deposited on a sapphire substrate to obtain a deep ultraviolet LED epitaxial wafer.

[0045] Step Two: As Figure 4 As shown in Figure b, by using photolithography and etching processes, the p-type GaN layer, p-type AlGaN layer, electron blocking layer, active region and part of the n-type AlGaN layer in a designated area are removed from top to bottom, thus forming a mesa structure and exposing part of the n-AlGaN.

[0046] Step 3: As Figure 4As shown in Figures c and d, a mask layer is deposited on the surface of the deep ultraviolet LED epitaxial wafer, and then patterned to form a mask layer window, allowing the surface of the n-type AlGaN layer exposed in step 2 to remain exposed. The mask layer can be made of materials such as silicon oxide, silicon nitride, or organic adhesive, which are easily removed in subsequent steps and will not contaminate the deep ultraviolet LED epitaxial wafer.

[0047] Step Four: As Figure 4 As shown in Figure e, a high-conductivity n-type semiconductor layer is deposited on the surface of a deep ultraviolet LED epitaxial wafer. The high-conductivity n-type semiconductor layer can be an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, an n-type Si layer, or other semiconductor layers that easily form ohmic contacts. The deposition methods can include metal-organic chemical vapor deposition, molecular beam epitaxy, laser pulse deposition, ion beam sputtering deposition, electron beam evaporation, thermal evaporation, etc.

[0048] When an n-type GaN layer is selected, silicon oxide or silicon nitride is preferably used as the mask layer, and it is prepared by metal-organic chemical vapor deposition or molecular beam epitaxy. In this case, the n-type GaN layer is selectively deposited only within the mask layer window.

[0049] Step 5: As Figure 4 As shown in Figure f, the mask layer and the high-conductivity n-type semiconductor layer attached thereon are removed by chemical etching or organic dissolution.

[0050] Step Six: As Figure 4 As shown in Figure g, a passivation layer is deposited on the surface of a deep ultraviolet (DUV) LED epitaxial wafer. The passivation layer can be a stacked structure of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, or a combination of these with other high-refractive-index dielectric layers (such as tin pentoxide, hafnium oxide, or zirconium oxide). When the passivation layer is a stacked structure, the thickness of each layer is one-quarter of its optical wavelength, thus providing good reflectivity for the emission wavelength of the DUV LED chip.

[0051] Step Seven: As Figure 4 As shown in Figure h, the passivation layers on the surfaces of the high-conductivity n-type semiconductor layer and the p-type GaN layer are removed respectively, and n-type ohmic contact electrodes and p-type ohmic contact electrodes are deposited on their surfaces respectively to obtain a deep ultraviolet LED chip.

[0052] Figure 5 A flowchart illustrating a method for fabricating a deep ultraviolet LED chip according to another embodiment of the present disclosure is shown.

[0053] like Figure 5 As shown, the method for fabricating a deep ultraviolet LED chip in this embodiment may include the following steps.

[0054] Step 1: As Figure 5As shown in Figure a, an AlN template layer, an n-type AlGaN layer, a multi-quantum well active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer are sequentially formed on a sapphire substrate to obtain a deep ultraviolet LED epitaxial wafer.

[0055] Step Two: As Figure 5 As shown in Figure b, a p-type ohmic contact electrode is deposited on the surface of a p-type GaN layer.

[0056] Step 3: As Figure 5 As shown in Figure c, the p-type ohmic contact electrode of the deep ultraviolet LED epitaxial wafer is bonded to another conductive substrate.

[0057] Step Four: As Figure 5 As shown in Figure d, the sapphire substrate from which the deep ultraviolet LED epitaxial wafer is removed. Removal methods include, but are not limited to, laser lift-off, dry etching, wet etching, photoelectrochemical etching, electrochemical etching, or mechanical lift-off.

[0058] Step 5: As Figure 5 As shown in Figure e, the AlN template layer of the deep ultraviolet LED epitaxial wafer is removed to expose the surface of the n-type AlGaN layer. Removal methods include, but are not limited to, dry etching, wet chemical etching based on alkaline solutions, and chemical mechanical polishing.

[0059] Step Six: As Figure 5 As shown in Figure f, a high-conductivity n-type gallium oxide-based semiconductor layer is deposited on the surface of an n-type AlGaN layer. The materials for the n-type gallium oxide-based semiconductor layer include gallium oxide, indium oxide, aluminum oxide, and their ternary and quaternary alloys. By adjusting the stoichiometric ratio of the metal elements in the materials, they are made transparent to the emission wavelength of deep ultraviolet LEDs. The deposition methods for the n-type gallium oxide-based semiconductor layer include metal-organic chemical vapor deposition, molecular beam epitaxy, laser pulse deposition, ion beam sputtering deposition, electron beam evaporation, and thermal evaporation.

[0060] Step Seven: As Figure 5 As shown in Figure g, an n-type ohmic contact electrode is deposited on a portion of the surface of a high-conductivity n-type gallium oxide-based semiconductor layer to obtain a vertically structured deep ultraviolet LED chip.

[0061] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A deep ultraviolet LED chip, characterized in that, include: The substrate, AlN template layer, n-type AlGaN layer, active region, electron blocking layer, p-type AlGaN layer and p-type ohmic contact electrode are stacked sequentially. In this structure, a portion of the n-type AlGaN layer is not covered by a p-type AlGaN layer, an electron blocking layer, or an active region, thus exposing the n-type AlGaN layer. A portion of the exposed n-type AlGaN layer is removed to form a mesa structure. An n-type semiconductor layer and an n-type ohmic contact electrode are formed on the exposed portion of the n-type AlGaN layer. The n-type semiconductor layer serves as both the n-type ohmic contact layer and the electron supply layer. The sidewalls of the mesa structure are covered with a passivation layer.

2. The deep ultraviolet LED chip according to claim 1, characterized in that, The n-type semiconductor layer includes an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, and an n-type Si semiconductor layer; the conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

3. The deep ultraviolet LED chip according to claim 1 or 2, characterized in that, A low-Al composition p-type Al2O3 layer is also formed between the p-type AlGaN layer and the p-type ohmic contact electrode. x Ga 1-x N layers, where 0 ≤ x ≤ 0.4; A hole blocking layer is further disposed between the n-type AlGaN and the active region, and the Al composition of the hole blocking layer is higher than that of the n-type AlGaN layer. A transition layer is also formed between the AlN template layer and the n-type AlGaN layer.

4. The deep ultraviolet LED chip according to claim 1 or 2, characterized in that, The passivation layer is a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide and aluminum nitride, or a stacked structure composed of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride and a dielectric layer.

5. A method for fabricating a deep ultraviolet LED chip, characterized in that, include: A substrate is provided, and an AlN template layer, an n-type AlGaN layer, an active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer are sequentially fabricated on the substrate to obtain a deep ultraviolet LED epitaxial wafer. Remove the p-type GaN layer, p-type AlGaN layer, electron blocking layer, active region, and part of the n-type AlGaN layer in the specified area to form a mesa structure, exposing part of the surface of the n-type AlGaN layer; A mask layer is deposited on the surface of a deep ultraviolet LED epitaxial wafer and patterned to form a mask layer window, allowing the exposed n-type AlGaN layer surface to remain exposed. A high-conductivity n-type semiconductor layer is deposited on the surface of a deep ultraviolet LED epitaxial wafer; Remove the mask layer and the high-conductivity n-type semiconductor layer attached thereon; A passivation layer is deposited on the surface of a deep ultraviolet LED epitaxial wafer; The passivation layers on the surfaces of the high-conductivity n-type semiconductor layer and the p-type GaN layer are removed separately, and n-type ohmic contact electrodes and p-type ohmic contact electrodes are deposited separately to obtain a deep ultraviolet LED chip.

6. A deep ultraviolet LED chip, characterized in that, include: The conductive substrate, p-type ohmic contact electrode, p-type AlGaN layer, electron blocking layer, multi-quantum well active region, n-type AlGaN layer, n-type semiconductor layer, and n-type ohmic contact electrode are stacked sequentially. The n-type semiconductor layer is used as an n-type ohmic contact layer and an electron supply layer.

7. The deep ultraviolet LED chip according to claim 6, characterized in that, The n-type semiconductor layer includes an n-type GaN-based semiconductor layer, an n-type oxide semiconductor layer, and an n-type Si semiconductor layer; the conductivity of the n-type semiconductor layer is greater than that of the n-type AlGaN layer.

8. The deep ultraviolet LED chip according to claim 6 or 7, characterized in that, The n-type semiconductor layer is opaque to the emission wavelength of the deep ultraviolet LED chip, and the n-type semiconductor layer and the n-type ohmic contact electrode partially cover the surface of the n-type AlGaN layer.

9. The deep ultraviolet LED chip according to claim 6 or 7, characterized in that, The n-type semiconductor layer is transparent to the emission wavelength of the deep ultraviolet LED chip, the n-type semiconductor layer covers the surface of the n-type AlGaN layer, and the n-type ohmic contact electrode partially covers the surface of the n-type AlGaN layer.

10. A method for fabricating a deep ultraviolet LED chip, characterized in that, include: A substrate is provided, and an AlN template layer, an n-type AlGaN layer, a multi-quantum-well active region, an electron blocking layer, a p-type AlGaN layer, and a p-type GaN layer are sequentially fabricated on the substrate to obtain a deep ultraviolet LED epitaxial wafer. A p-type ohmic contact electrode is deposited on the surface of the p-type GaN layer of the deep ultraviolet LED epitaxial wafer; The p-type ohmic contact electrode is bonded to a conductive substrate; The substrate and AlN template layer of the deep ultraviolet LED epitaxial wafer are removed sequentially to expose the n-type AlGaN layer; An n-type semiconductor layer is deposited on the surface of an n-type AlGaN layer, and an n-type ohmic contact electrode is deposited on the surface of the n-type semiconductor layer to obtain the deep ultraviolet LED chip.

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