Integrated structure of photodetector and light emitting diode and preparation method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI
- Filing Date
- 2024-12-26
- Publication Date
- 2026-06-26
Smart Images
Figure CN122294615A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor device technology, specifically relating to an integrated structure of a photodetector and a light-emitting diode and its fabrication method. Background Technology
[0002] Ultraviolet (UV) optoelectronic technology and its detection techniques have significant research value in various fields, including military, civilian, industrial, and scientific research, such as UV communication, disinfection, and ozone monitoring. With the development of electronic information, electronic devices are trending towards miniaturization and integration. Traditional integrated devices typically use dispensing processes to encapsulate LED devices with other devices (usually horizontally structured devices). Horizontal bonding is a complex process, difficult to manufacture, and has low cost and efficiency.
[0003] Wide-bandgap semiconductors gallium nitride (GaN) and aluminum nitride (AlN) have wurtzite crystal structures with a hexagonal lattice as their underlying layer. This crystal structure breaks inversion symmetry along the
[0001] direction (c-axis). Therefore, the two surfaces perpendicular to the c-axis of these polar semiconductor monocrystalline wafers exhibit very different physical properties: flipping the wafer is analogous to flipping a bar magnet. The chemical properties on both sides are so different that they have been used to identify the surface polarity of the metal or nitrogen. Over the past three decades, the cation (gallium) polar surface of GaN has been used to fabricate photonic devices such as light-emitting diodes (LEDs) and lasers, while the anion (nitrogen) polar surface has recently shown promise for fabricating high electron mobility transistors (HEMTs). To achieve high emission efficiency, the metallic polar surface of the substrate can be used to fabricate any optoelectronic device, such as semiconductor laser tubes, semiconductor optical amplifiers, and optoelectronic modulators, while transistors or photodetectors are fabricated on the N-polar surface. Thus, it is hoped that this remarkable property of GaN substrates can be utilized to create and manipulate electrons and photons on opposite surfaces of the same substrate to achieve new functionalities.
[0004] Therefore, to address the aforementioned technical problems, it is necessary to provide an integrated structure and fabrication method for a photodetector and a light-emitting diode. Summary of the Invention
[0005] The purpose of this invention is to provide an integrated structure of a photodetector and a light-emitting diode and its fabrication method, which enables the photodetector to drive the light-emitting diode to emit light on the same substrate.
[0006] To achieve the above objectives, an embodiment of the present invention provides the following technical solution:
[0007] An integrated structure of a photodetector and a light-emitting diode, the integrated structure comprising:
[0008] GaN substrate, the GaN substrate including Ga polar surface and N polar surface disposed opposite to each other;
[0009] Light-emitting diodes (LEDs) are integrated on the Ga polar surface of a GaN substrate.
[0010] The photodetector is integrated on the N-polar surface of the GaN substrate.
[0011] In one embodiment, the photodetector includes an AlGaN layer on the N-polar surface, and a first electrode and a second electrode on the AlGaN layer. The first electrode has an array of nanopores that extend through the AlGaN layer.
[0012] In one embodiment, the first electrode includes a first main body, a first extension, and a connecting portion connecting the first main body and the first extension, wherein the nanopore is located on the first extension. The second electrode includes a second main body and a second extension extending outward from the second main body, wherein the second extension is located around the first extension and the connecting portion, and the first main body is located between the two ends of the second extension.
[0013] In one embodiment, the first electrode is a single-crystal Al electrode, and the second electrode is an Au electrode or a Ti / Au electrode.
[0014] In one embodiment, the diameter of the nanopore is 20 nm to 400 nm, and the spacing between adjacent nanopores is 20 nm to 400 nm.
[0015] In one embodiment, the thickness of the first electrode is 50 nm to 150 nm, and the thickness of the second electrode is greater than or equal to 50 nm.
[0016] In one embodiment, the light-emitting diode includes a buffer layer, an N-type semiconductor layer, a quantum well layer and a P-type semiconductor layer stacked sequentially on a Ga polar surface. The P-type semiconductor layer has a third electrode electrically connected to the P-type semiconductor layer, and the buffer layer has a fourth electrode electrically connected to the N-type semiconductor layer.
[0017] In one embodiment, the buffer layer is an AlN layer; and / or,
[0018] The N-type semiconductor layer is an N-type AlGaN layer, and the P-type semiconductor layer is a P-type AlGaN layer.
[0019] Another embodiment of the present invention provides the following technical solution:
[0020] A method for fabricating an integrated structure of a photodetector and a light-emitting diode, the method comprising the following steps:
[0021] A GaN substrate is provided, the GaN substrate comprising a Ga polar facet and an N polar facet disposed opposite to each other;
[0022] Light-emitting diodes are fabricated on the Ga polar facet of a GaN substrate;
[0023] A photodetector is fabricated on the N-polar facet of a GaN substrate.
[0024] In one embodiment, a light-emitting diode is fabricated on the Ga polar side of a GaN substrate, and a photodetector is fabricated on the N polar side of the GaN substrate, comprising the following steps:
[0025] In a vacuum interconnect device, a buffer layer, an N-type semiconductor layer, a quantum well layer, and a P-type semiconductor layer are sequentially fabricated on a Ga polar surface.
[0026] AlGaN layers and single-crystal Al layers are fabricated on the N-polar surface in a vacuum interconnect device;
[0027] The P-type semiconductor layer, quantum well layer, and N-type semiconductor layer are etched sequentially to form steps. A third electrode electrically connected to the P-type semiconductor layer is fabricated on the P-type semiconductor layer, and a fourth electrode electrically connected to the N-type semiconductor layer is fabricated on the buffer layer.
[0028] A first electrode with an array of nanopores is formed by etching a single-crystal Al layer, the nanopores extending into the AlGaN layer, and a second electrode is fabricated on the AlGaN layer.
[0029] Compared with the prior art, the present invention has the following beneficial effects:
[0030] This invention utilizes the unique physical properties of GaN substrates to fabricate light-emitting diodes and photodetectors on the Ga polar surface and N polar surface of GaN substrates, respectively, thereby integrating photodetectors and light-emitting diodes on the same substrate.
[0031] This invention utilizes a single-crystal Al electrode as the first electrode of a photodetector and fabricates an array of nanopores on the first electrode. By utilizing the plasmon effect, the photoelectric effect of the photodetector is improved, thereby enabling the photodetector to drive a light-emitting diode to emit light. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a schematic diagram of the integrated structure of the photodetector and the light-emitting diode in Embodiment 1 of the present invention;
[0034] Figure 2This is a top view of the first and second electrodes in Embodiment 1 of the present invention;
[0035] Figures 3a-3e This is a process flow diagram of the fabrication method of the integrated structure of photodetector and light-emitting diode in Embodiment 1 of the present invention.
[0036] Explanation of key figure labels:
[0037] 1-GaN substrate, 21-buffer layer, 22-N-type semiconductor layer, 23-quantum well layer, 24-P-type semiconductor layer, 251-third electrode, 252-fourth electrode, 31-AlGaN layer, 321-first electrode, 3211-first main body, 3212-first extension, 3213-connector, 322-second electrode, 3221-second main body, 3222-second extension, 4-single crystal Al layer. Detailed Implementation
[0038] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0039] This invention discloses an integrated structure of a photodetector and a light-emitting diode, comprising:
[0040] The GaN substrate includes a Ga polar surface and an N polar surface disposed opposite to each other.
[0041] Light-emitting diodes (LEDs) are integrated on the Ga polar surface of a GaN substrate.
[0042] The photodetector is integrated on the N-polar surface of the GaN substrate.
[0043] This invention also discloses a method for fabricating an integrated structure of a photodetector and a light-emitting diode, comprising the following steps:
[0044] A GaN substrate is provided, the GaN substrate including a Ga polar facet and an N polar facet disposed opposite to each other;
[0045] Light-emitting diodes are fabricated on the Ga polar facet of a GaN substrate;
[0046] A photodetector is fabricated on the N-polar facet of a GaN substrate.
[0047] The present invention will be further illustrated below with specific examples.
[0048] Example 1:
[0049] As shown Figure 1 in the figure, the integrated structure of the photodetector and the light-emitting diode in this embodiment includes:
[0050] A GaN substrate 1, the GaN substrate 1 includes a Ga-polarity surface and an N-polarity surface arranged opposite to each other;
[0051] A light-emitting diode, integrated on the Ga-polarity surface of the GaN substrate 1;
[0052] A photodetector, integrated on the N-polarity surface of the GaN substrate 1.
[0053] Among them, the photodetector in this embodiment is an ultraviolet photodetector, and the light-emitting diode is an ultraviolet light-emitting diode. The light-emitting diode includes, but is not limited to, a light-emitting diode structure based on AlGaN or GaN.
[0054] Exemplarily, the light-emitting diode in this embodiment includes a buffer layer 21, an N-type semiconductor layer 22, a quantum well layer 23, and a P-type semiconductor layer 24 that are sequentially stacked on the Ga-polarity surface.
[0055] Specifically, the buffer layer 21 in this embodiment is an AlN layer, the N-type semiconductor layer 22 is an N-type AlGaN layer, and the P-type semiconductor layer 24 is a P-type AlGaN layer.
[0056] In addition, a third electrode 251 electrically connected to the P-type semiconductor layer 24 is provided on the P-type semiconductor layer 24. The third electrode 251 is an indium tin oxide (ITO) transparent conductive layer, and a fourth electrode 252 electrically connected to the N-type semiconductor layer 22 is provided on the buffer layer 21. The fourth electrode 252 is a conventional Ti / Au electrode.
[0057] Further, the photodetector in this embodiment includes an AlGaN layer 31 on the N-polarity surface of the GaN substrate, and a first electrode 321 and a second electrode 322 on the AlGaN layer 31. Nanopores are arranged in an array on the first electrode 321 and penetrate through to the AlGaN layer 31.
[0058] Specifically, the first electrode 321 in this embodiment is a single-crystal Al electrode. Using Al metal as the electrode reduces the carrier diffusion and drift time. And compared with polycrystalline Al, single-crystal Al can generate stronger localized surface plasmon resonance (LSPR), which can improve the photoelectric effect of the detector to facilitate better absorption of ultraviolet light. The second electrode 322 in this example is an Au electrode or a TiAu electrode, which is used to form an ohmic contact with the AlGaN layer 31.
[0059] More specifically, as shown Figure 2 As shown, in this embodiment, the first electrode 321 includes a first main body 3211, a first extension 3212, and a connecting portion 3213 connecting the first main body 3211 and the first extension 3212. The nanopore is located on the first extension 3212. The second electrode 322 includes a second main body 3221 and a second extension 3222 extending outward from the second main body 3221. The second extension 3222 is located around the first extension 3212 and the connecting portion 3213, and the first main body 3211 is located between the two ends of the second extension 3222.
[0060] The thickness of the first electrode 321 is 50 nm to 150 nm, and the thickness of the second electrode 322 is greater than or equal to 50 nm. The diameter of the nanopores on the first electrode 321 is 20 nm to 400 nm, and the spacing between adjacent nanopores is 20 nm to 400 nm. Under these structural parameters, the nanopores are coupled together, greatly expanding the bandwidth and enabling coverage of the entire ultraviolet region.
[0061] In this embodiment, a single-crystal Al electrode is used as the first electrode 321, and an array of nanopores is fabricated on the first electrode 321 to generate localized surface plasmon resonance. The scattering effect of Al metal nanoparticles enhances the absorption of ultraviolet light by the AlGaN layer, and the excited localized surface plasmons effectively strengthen the electric field, improving the absorption capacity of the photosensitive region of the AlGaN layer. Furthermore, the localized electric field enhanced by the plasmon effect promotes the separation of electron-hole pairs in the photosensitive material. Simultaneously, localized surface plasmon resonance generates heat carriers in the Al metal and overcomes the Schottky barrier metal / semiconductor interface, thereby promoting carrier transport. Based on this, the photodetector can generate a fast time response, significantly enhance the photoelectric effect, and excite the light-emitting diode to emit light.
[0062] The fabrication method of the integrated structure of photodetector and light-emitting diode in this embodiment includes the following steps:
[0063] S1, Reference Figure 3a As shown, a GaN substrate 1 is provided, which includes a Ga polar surface and an N polar surface disposed opposite to each other.
[0064] S2. A light-emitting diode is fabricated on the Ga polar facet of GaN substrate 1.
[0065] S3. Fabricate a photodetector on the N-polar surface of GaN substrate 1.
[0066] Specifically, the method for preparing the integrated structure in this embodiment includes:
[0067] 1. Reference Figure 3bAs shown, a cleaned GaN substrate 1 is placed in a vacuum interconnect device, and a buffer layer 21, an N-type semiconductor layer 22, a quantum well layer 23, and a P-type semiconductor layer 24 are sequentially fabricated on the Ga polar surface.
[0068] Among them, the buffer layer 21 is an AlN layer, the N-type semiconductor layer 22 is an N-type AlGaN layer, and the P-type semiconductor layer 24 is a P-type AlGaN layer.
[0069] The vacuum interconnect device in this embodiment includes at least a metal-organic chemical vapor deposition (MOCVD) apparatus and a molecular beam epitaxy (MBE) apparatus. This step uses a metal-organic chemical vapor deposition process to sequentially grow the aforementioned structure on a Ga polar surface.
[0070] 2. Reference Figure 3c As shown, in the vacuum interconnect device, the GaN substrate 1 with the above structure is flipped, and an AlGaN layer 31 and a single-crystal Al layer 4 are sequentially prepared on the N-polar surface.
[0071] For example, a single-crystal Al layer 4 is grown using molecular beam epitaxy.
[0072] In this embodiment, the epitaxial structure and single-crystal Al layer are grown on the Ga polar facet and N polar facet of the GaN substrate in a vacuum interconnect device. The entire growth process is carried out in a vacuum, which can effectively avoid oxidation and contamination of the interface caused by external air.
[0073] 3. Participate Figure 3d As shown, the P-type semiconductor layer 24, the quantum well layer 23, and the N-type semiconductor layer 22 are etched sequentially to form steps, and a third electrode 251 is fabricated on the P-type semiconductor layer 24, and a fourth electrode 252 is fabricated on the buffer layer 21.
[0074] The third electrode 251 is an indium tin oxide transparent conductive layer, which is electrically connected to the P-type semiconductor layer 24. The fourth electrode 252 is a conventional Ti / Au electrode, which is electrically connected to the N-type semiconductor layer 22.
[0075] 4. Participate Figure 3e As shown, the single-crystal Al layer 4 is etched to form a first electrode 321 with an array of nanopores. The nanopores extend into the AlGaN layer 31, and a second electrode 322 is fabricated on the AlGaN layer 31.
[0076] Specifically, a mask is first prepared on a single-crystal Al layer 4 using a patterning process, then the single-crystal Al layer 4 is etched to form the first electrode 321, and finally the second electrode 322 is prepared on the AlGaN layer 31 to complete the preparation of the integrated structure of photodetector and light-emitting diode.
[0077] As can be seen from the above technical solution, the present invention has the following beneficial effects:
[0078] This invention utilizes the unique physical properties of GaN substrates to fabricate light-emitting diodes and photodetectors on the Ga polar surface and N polar surface of GaN substrates, respectively, thereby integrating photodetectors and light-emitting diodes on the same substrate.
[0079] This invention utilizes a single-crystal Al electrode as the first electrode of a photodetector and fabricates an array of nanopores on the first electrode. By utilizing the plasmon effect, the photoelectric effect of the photodetector is improved, thereby enabling the photodetector to drive a light-emitting diode to emit light.
[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. An integrated structure of a photodetector and a light-emitting diode, characterized in that, The integrated structure includes: GaN substrate, the GaN substrate including Ga polar surface and N polar surface disposed opposite to each other; Light-emitting diodes (LEDs) are integrated on the Ga polar surface of a GaN substrate. The photodetector is integrated on the N-polar surface of the GaN substrate.
2. The photodetector and light-emitting diode integrated structure according to claim 1, characterized in that, The photodetector includes an AlGaN layer on the N-polar surface, and a first electrode and a second electrode on the AlGaN layer. The first electrode has an array of nanopores that extend into the AlGaN layer.
3. The photodetector and light-emitting diode integrated structure according to claim 2, characterized in that, The first electrode includes a first main body, a first extension, and a connecting portion connecting the first main body and the first extension. The nanopore is located on the first extension. The second electrode includes a second main body and a second extension extending outward from the second main body. The second extension is located around the first extension and the connecting portion, and the first main body is located between the two ends of the second extension.
4. The photodetector and light-emitting diode integrated structure according to claim 2, characterized in that, The first electrode is a single-crystal Al electrode, and the second electrode is an Au electrode or a Ti / Au electrode.
5. The photodetector and light-emitting diode integrated structure according to claim 2, characterized in that, The diameter of the nanopores is 20 nm to 400 nm, and the spacing between adjacent nanopores is 20 nm to 400 nm.
6. The photodetector and light-emitting diode integrated structure according to claim 2, characterized in that, The thickness of the first electrode is 50 nm to 150 nm, and the thickness of the second electrode is greater than or equal to 50 nm.
7. The photodetector and light-emitting diode integrated structure according to claim 1, characterized in that, The light-emitting diode includes a buffer layer, an N-type semiconductor layer, a quantum well layer and a P-type semiconductor layer stacked sequentially on the Ga polar surface. The P-type semiconductor layer has a third electrode electrically connected to the P-type semiconductor layer, and the buffer layer has a fourth electrode electrically connected to the N-type semiconductor layer.
8. The photodetector and light-emitting diode integrated structure according to claim 7, characterized in that, The buffer layer is an AlN layer; and / or, The N-type semiconductor layer is an N-type AlGaN layer, and the P-type semiconductor layer is a P-type AlGaN layer.
9. A method for fabricating an integrated structure of a photodetector and a light-emitting diode, characterized in that, The preparation method includes the following steps: A GaN substrate is provided, the GaN substrate comprising a Ga polar facet and an N polar facet disposed opposite to each other; Light-emitting diodes are fabricated on the Ga polar facet of a GaN substrate; A photodetector is fabricated on the N-polar facet of a GaN substrate.
10. The method for fabricating the integrated structure of photodetector and light-emitting diode according to claim 9, characterized in that, Fabricating a light-emitting diode on the Ga polar side of a GaN substrate and a photodetector on the N polar side of the GaN substrate includes the following steps: In a vacuum interconnect device, a buffer layer, an N-type semiconductor layer, a quantum well layer, and a P-type semiconductor layer are sequentially fabricated on a Ga polar surface. AlGaN layers and single-crystal Al layers are fabricated on the N-polar surface in a vacuum interconnect device; The P-type semiconductor layer, quantum well layer, and N-type semiconductor layer are etched sequentially to form steps. A third electrode electrically connected to the P-type semiconductor layer is fabricated on the P-type semiconductor layer, and a fourth electrode electrically connected to the N-type semiconductor layer is fabricated on the buffer layer. A single-crystal Al layer is etched to form a first electrode with an array of nanopores that extend into the AlGaN layer, and a second electrode is fabricated on the AlGaN layer.