A short-wave infrared photodetector and method of manufacturing the same

Abstract

The application discloses a short-wave infrared photoelectric detector and a manufacturing method thereof. The short-wave infrared photoelectric detector comprises a substrate structure, a first doped layer and a buried oxygen layer which are arranged in a stack; the first doped layer is a germanium layer with a first conductivity type; an absorption layer is arranged on a side of the first doped layer in the substrate structure, away from the buried oxygen layer; the absorption layer is an intrinsic germanium layer; a second doped layer is arranged on a side of the absorption layer, away from the substrate structure; the second doped layer is a III-V group material layer with a second conductivity type; and the second conductivity type is opposite to the first conductivity type. The embodiment of the application can effectively reduce the dark current of the germanium-based short-wave infrared detector.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detector technology, and in particular to a short-wave infrared photoelectric detector and its manufacturing method. Background Technology

[0002] Short-wave infrared (SWIR) generally refers to the electromagnetic band with wavelengths ranging from 0.9 μm to 1.7 μm. This band combines the imaging advantages of visible light and mid-infrared light, therefore, short-wave infrared imaging technology has wide application value in fields such as night vision surveillance, remote sensing, industrial inspection, autonomous driving, biomedical imaging, and national defense security.

[0003] Currently, germanium materials possess high absorption coefficients, mature semiconductor processing capabilities, and CMOS compatibility in the near-infrared to short-wave infrared bands, thus demonstrating significant potential in the field of low-cost, high-performance short-wave infrared detectors. However, existing germanium-based short-wave infrared detectors still commonly suffer from excessively high dark current in practical applications. Summary of the Invention

[0004] This invention provides a shortwave infrared photodetector and its manufacturing method to solve the problem of excessive dark current in germanium-based shortwave infrared detectors.

[0005] According to one aspect of the present invention, a short-wave infrared photodetector is provided, comprising: The substrate structure includes a silicon substrate, a buried oxide layer, and a first doped layer stacked together; the first doped layer is configured as a germanium layer having a first conductivity type. An absorption layer is disposed on the side of the first doped layer in the substrate structure away from the buried oxide layer; the absorption layer is an intrinsic germanium layer. A second doped layer is disposed on the side of the absorption layer away from the substrate structure; the second doped layer is configured as a III-V group material layer having a second conductivity type. The second conductivity type is the opposite of the first conductivity type.

[0006] Optionally, the first doped layer is a germanium layer of N-type conductivity, and the second doped layer is a III-V material layer of P-type conductivity. Alternatively, the first doped layer may be a germanium layer of P-type conductivity, and the second doped layer may be a III-V material layer of N-type conductivity.

[0007] Optionally, the III-V group material layer includes an AlAs material layer or a GaAs material layer; The thickness of the III-V group material layer ranges from 200 to 300 nm.

[0008] Optionally, the thickness of the first doped layer ranges from 500 to 1000 nm, and the crystal defect density ranges from 10. 5 ~10 6 cm -2 The doping concentration range is 10. 18 ~ 10 19 cm -3 .

[0009] Optionally, the thickness of the absorption layer ranges from 500 to 2000 nm.

[0010] Optionally, the short-wave infrared photodetector further includes: a passivation layer, a first electrode, and a second electrode; The second doped layer has trenches, the bottom of which exposes the first doped layer; The passivation layer covers the surface of the second doped layer and the inner wall of the trench; The first electrode is electrically connected to the first doped layer, and the second electrode is electrically connected to the second doped layer.

[0011] According to another aspect of the present invention, a method for manufacturing a shortwave infrared photodetector is provided, comprising: A substrate structure is provided; the substrate structure includes a silicon substrate, a buried oxide layer, and a first doped layer stacked thereon; the first doped layer is configured as a germanium layer having a first conductivity type. On the side of the first doped layer in the substrate structure away from the buried oxide layer, an intrinsic germanium layer is homoepitaxially grown to form an absorption layer. A III-V group material layer is heteroepitaxially grown on the side of the absorption layer away from the substrate structure to form a second doped layer; the second doped layer has a second conductivity type, which is opposite to the first conductivity type.

[0012] Optionally, the step of heteroepitaxially growing a III-V group material layer on the side of the absorption layer away from the substrate structure to form a second doped layer includes: A second doped layer is formed by heteroepitaxial growth of an AlAs or GaAs material layer on the side of the absorption layer away from the substrate structure.

[0013] Optionally, the provision of the substrate structure includes: A substrate is provided; the substrate includes a silicon substrate, a buried oxide layer, and a germanium layer stacked thereon; The germanium layer is implanted with conductive ions of a first conductivity type using an ion implantation method to form the first doped layer.

[0014] Optionally, the manufacturing method of the shortwave infrared photodetector further includes: The second doped layer is etched to form a trench; the bottom of the trench exposes the first doped layer. An insulating material is deposited on the surface of the second doped layer to form a passivation layer; the passivation layer covers the surface of the second doped layer and the inner wall of the trench; A first electrode is formed by depositing metal material at the bottom of the trench, and a second electrode is formed by depositing metal material on the side of the passivation layer away from the second doped layer; wherein the first electrode is electrically connected to the first doped layer, and the second electrode is electrically connected to the second doped layer.

[0015] The short-wave infrared photodetector provided in this invention uses a GOI substrate with a stacked silicon substrate, a buried oxide layer, and a first doped layer as the substrate structure. The first doped layer is a germanium layer with a first conductivity type after doping, which is beneficial for forming a controlled electric field region, enabling efficient migration and collection of charge carriers along the desired direction and reducing dark current. An absorption layer is formed on the surface of the substrate structure. The absorption layer is an intrinsic germanium layer, which forms a homojunction with the first doped layer in the substrate structure. This improves the crystal quality of the absorption layer and reduces the defect density, thereby effectively reducing dark current. A second doped layer is formed on the side of the absorption layer away from the substrate structure. The second doped layer is a III-V group material layer with a second conductivity type after doping. Since the conductivity type of the second doped layer is opposite to that of the first doped layer, the second doped layer, the absorption layer, and the first doped layer form a PIN structure, which enables precise control of the charge carrier flow direction. Furthermore, the second doped layer and the absorption layer have a high lattice matching degree, and the III-V group material layer with the second conductivity type forms a large band level difference with the absorption layer, which can effectively block thermally excited carriers and reverse injected carriers, thereby effectively suppressing the generation of dark current.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a shortwave infrared photodetector provided according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of another shortwave infrared photodetector provided according to an embodiment of the present invention; Figure 3 This is a schematic flowchart of a manufacturing method for a shortwave infrared photodetector according to an embodiment of the present invention; Figures 4 to 5 yes Figure 3 A structural diagram corresponding to each step in the process; Figure 6 This is a schematic diagram of the specific process of step S110 in a manufacturing method of a shortwave infrared photodetector provided according to an embodiment of the present invention. Figure 7 yes Figure 6 A schematic diagram of the structure corresponding to the relevant steps. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] As described in the background section, the electromagnetic band corresponding to short-wave infrared combines the imaging advantages of visible light and mid-infrared, enabling high-resolution imaging in complex environments such as low illumination, smoke, and haze. With increasing demands for sensitivity, signal-to-noise ratio, and spatial resolution in imaging systems, short-wave infrared detectors require the following performance indicators: high quantum efficiency for efficient optical signal conversion; low dark current and low noise to ensure clear imaging; and good temperature stability and process compatibility to adapt to mass production and integrated applications. Currently, commonly used short-wave infrared detector material systems include InGaAs, HgCdTe, and germanium (Ge). Among them, germanium exhibits high absorption coefficients, mature semiconductor processes, and CMOS compatibility in the near-infrared to short-wave infrared bands, thus showing great potential in the field of low-cost, high-performance short-wave infrared detectors. Germanium-based short-wave infrared detectors in related technologies mainly employ PIN structures, but in practical applications, excessively high dark current is still a common problem, mainly manifested in the following aspects: The narrow bandgap of germanium materials results in a high intrinsic carrier concentration at room temperature, leading to a significant increase in thermally excited carriers and thus a large intrinsic dark current. Furthermore, the interface between germanium and the substrate or other semiconductor materials readily generates defect states, which become carrier recombination centers, further increasing the dark current. This high dark current directly reduces the signal-to-noise ratio of the detector, limiting the application of short-wave infrared detectors in high-performance imaging systems.

[0022] Specifically, germanium short-wave infrared detectors in related technologies often employ a PIN structure, achieving photoelectric conversion through a germanium absorption layer. However, in traditional detectors, the germanium absorption layer is typically grown on silicon or other substrates, leading to lattice matching issues and interface defects. This can easily result in crystal defects, generating recombination dark currents, reducing photoelectric conversion efficiency, and affecting device performance. Furthermore, to improve photoelectric response, some studies have attempted to introduce other semiconductor heterolayers on top of the germanium material, but these lack systematic bandgap design, failing to effectively block thermally excited carriers or suppress reverse injection, making it difficult to simultaneously achieve high absorption efficiency and dark current suppression. Moreover, some heterojunction formation schemes do not fully consider substrate characteristics, resulting in uneven epitaxial quality, interface defects, and device reliability issues, hindering large-scale mass production and room-temperature stable operation.

[0023] Based on the above-mentioned technical problems, the embodiments of the present invention propose the following technical solutions: This invention provides a short-wave infrared photodetector. Figure 1 This is a schematic diagram of a short-wave infrared photodetector provided in an embodiment of the present invention. Figure 1 As shown, the short-wave infrared photodetector includes: The substrate structure 100 includes a silicon substrate 101, a buried oxide layer 102, and a first doped layer 103 stacked together; the first doped layer 103 is configured as a germanium layer having a first conductivity type. An absorption layer 200 is disposed on the side of the first doped layer 103 in the substrate structure 100 away from the buried oxide layer 102; the absorption layer 200 is an intrinsic germanium layer. The second doped layer 300 is disposed on the side of the absorber layer 200 away from the substrate structure 100; the second doped layer 300 is a III-V group material layer having a second conductivity type. The second conductivity type is the opposite of the first conductivity type.

[0024] Specifically, the substrate structure 100 uses a germanium-on-insulator (GOI) wafer, which is a semiconductor material composed of an insulating substrate layer and a germanium layer, and is a high-end silicon-based substrate material. In this embodiment of the invention, the substrate structure 100 includes a silicon substrate 101, a buried oxide layer 102, and a first doped layer 103 stacked from bottom to top. The buried oxide layer 102 can be a silicon dioxide layer, and the first doped layer 103 can be a germanium material layer doped with corresponding conductive ions and having a first conductivity type. Using a GOI wafer as the initial substrate provides a high-quality germanium material layer with low lattice defects, reducing the impact of structural defects such as dislocations, vacancies, and grain boundaries on carrier recombination, thereby reducing intrinsic dark current. Furthermore, the buried oxide layer 102 in the GOI substrate can effectively block the leakage current path between the germanium material layer of the first doped layer 103 and the silicon substrate 101, reducing carrier recombination and leakage current caused by interface states, playing a crucial role in suppressing the dark current of the detector. GOI substrates are used to improve the material quality of the absorption layer and the isolation performance of the detector. They not only have high electron and hole mobility and a high absorption coefficient in the communication band, but also reduce defect density, lower lattice stress, and provide an electrically insulating layer. They also achieve high quantum efficiency and high bandwidth, thereby effectively improving the performance of the detector.

[0025] In this embodiment of the invention, the germanium material layer in the GOI wafer used in the substrate structure 100 is configured as a germanium layer with a first conductivity type after doping, namely, a first doped layer 103. By doping the germanium material layer, a controlled electric field region can be formed on the top of the germanium material layer 103, which is beneficial for the efficient migration and collection of charge carriers along the desired direction and reduces the diffusion of charge carriers in undesired directions, thereby helping to reduce dark current. Furthermore, reasonable doping of the germanium material layer can ensure the uniform distribution of charge carriers, which is beneficial for optimizing the detector's response speed and photoelectric conversion efficiency.

[0026] An absorption layer 200 is disposed on the surface of the first doped layer 103 in the substrate structure 100. The absorption layer 200 is an intrinsic germanium layer formed by homoepitaxial growth, forming a homojunction with the first doped layer 103. This ensures that the absorption layer 200 has high crystal quality and low defect density, avoiding dislocations and lattice defects generated during growth, thus providing a foundation for efficient photoelectric conversion of the detector. At the same time, the high-quality absorption layer 200 can reduce defect recombination centers, effectively reducing dark current, and providing conditions for efficient carrier migration along the desired direction, which can further improve the signal-to-noise ratio.

[0027] A second doped layer 300, consisting of a III-V group material with a second conductivity type, is disposed on the surface of the absorption layer 200. This second doped layer 300 forms a bandgap at the top of the absorption layer 200, blocking thermally excited and reverse-injected carriers and effectively suppressing dark current generation. Furthermore, the second doped layer 300 forms a heterojunction with the absorption layer 200, and the two layers have a high lattice matching degree, ensuring the epitaxial interface quality of the second doped layer 300, reducing interface defect recombination centers, and improving the photoelectric conversion efficiency and response speed of the detector. Since the second conductivity type of the second doped layer 300 is opposite to the first conductivity type of the first doped layer 103, the first doped layer 103, the absorption layer 200, and the second doped layer 300 in the substrate structure 100 constitute a PIN structure. The second doped layer 300 allows adjustment of the bandgap position of the heterolayer and creates a significant bandgap difference with the absorption layer 200, thereby enabling precise control of carrier flow direction.

[0028] The short-wave infrared photodetector provided in this embodiment of the invention uses a GOI substrate 100, consisting of a silicon substrate 101, a buried oxide layer 102, and a first doped layer 103, stacked together. The first doped layer 103 is a germanium layer with a first conductivity type after doping, which facilitates the formation of a controlled electric field region, enabling efficient migration and collection of charge carriers along the desired direction and reducing dark current. An absorption layer 200, an intrinsic germanium layer, is disposed on the surface of the substrate structure 100. The intrinsic germanium layer forms a homojunction with the first doped layer 103 in the substrate structure 100, which can improve the crystal quality of the absorption layer 200 and reduce the defect density, thereby effectively reducing dark current. A second doped layer 300, a III-V group material layer with a second conductivity type, is disposed on the side of the absorption layer 200 away from the substrate structure 100. Since the second doped layer 300 has an opposite conductivity type to the first doped layer 103, the second doped layer 300, the absorber layer 200, and the first doped layer 103 form a PIN structure, enabling precise control of carrier flow direction. Furthermore, the second doped layer 300 and the absorber layer 200 have a high lattice matching degree, and the III-V group material layer with the second conductivity type forms a large band structure difference with the absorber layer 200, effectively blocking thermally excited carriers and reverse-injected carriers, thereby effectively suppressing the generation of dark current.

[0029] Based on the above embodiments, optionally, the first doped layer 103 is a germanium layer of N-type conductivity, and the second doped layer 300 is a III-V group material layer of P-type conductivity; Alternatively, the first doped layer 103 may be configured as a germanium layer of P-type conductivity, and the second doped layer 300 may be configured as a III-V group material layer of N-type conductivity.

[0030] Specifically, to form a PIN structure detector, the conductivity types of the first doped layer 103 and the second doped layer 300 can be set to opposite types, and an intrinsic germanium absorption layer 200 can be placed between the first doped layer 103 and the second doped layer 300 to form a PIN structure. This facilitates the adjustment of the heterolayer band position, enables precise control of carrier flow direction, enhances the carrier collection capability of the vertical PIN structure, and effectively improves the detector's response efficiency and sensitivity. The specific conductivity type can be set by the user according to actual manufacturing requirements and is not limited here. For example, a certain concentration of pentavalent elements such as phosphorus is implanted into the germanium layer on the side of the buried oxide layer 102 away from the silicon substrate 101 in the substrate structure 100 to form an N-type conductivity type first doped layer 103; while a certain concentration of trivalent elements such as boron is implanted into the III-V group material layer formed on the surface of the absorption layer 200 to form a P-type conductivity type second doped layer 300. Alternatively, a certain concentration of trivalent elements such as boron can be implanted into the germanium layer on the side of the buried oxide layer 102 away from the silicon substrate 101 in the substrate structure 100 to form a first doped layer 103 of P-type conductivity; while a certain concentration of pentavalent elements such as phosphorus can be implanted into the III-V group material layer formed on the surface of the absorption layer 200 to form a second doped layer 300 of N-type conductivity.

[0031] Based on the above embodiments, optionally, the III-V group material layer includes an AlAs material layer or a GaAs material layer; The thickness of the III-V group material layer ranges from 200 to 300 nm.

[0032] Specifically, a III-V material layer, either AlAs or GaAs, is used as the second doped layer 300 on the surface of the absorption layer 200. Compared with other III-V materials, it can further form a larger band order difference with the intrinsic germanium layer of the absorption layer 200, thereby effectively blocking thermally excited carriers and reverse-injected carriers, further suppressing the generation of dark current, and thus fundamentally improving the signal-to-noise ratio and detectivity of the detector.

[0033] Setting the thickness of the III-V group material layer in the second doped layer 300 to 200-300 nm allows for an effective bandgap difference with the absorption layer 200 while ensuring compatibility with subsequent electrode deposition and device packaging processes. This facilitates the mass production of high-performance devices. If the thickness of the second doped layer 300 is too large, lattice cracks or defects may occur during growth; if the thickness of the second doped layer 300 is too small, it may affect subsequent device packaging processes and increase the difficulty of mass production.

[0034] Based on the above embodiments, optionally, the thickness of the first doped layer 103 is in the range of 500 ~ 1000 nm, and the crystal defect density is in the range of 10.5 ~ 10 6 cm -2 The doping concentration range is 10. 18 ~ 10 19 cm -3 .

[0035] Specifically, setting the thickness of the first doped layer 103 in the substrate structure 100 within the range of 500~1000nm ensures sufficient growth space for the absorption layer 200, while controlling crystal stress to avoid lattice cracks or defects. This results in the absorption layer 200 having high crystal quality and low defect density, further reducing dark current. If the thickness of the first doped layer 103 is too large, lattice cracks or defects may occur; if the thickness of the first doped layer 103 is too small, it may affect the crystal quality of the absorption layer 200 homogeneously formed on the surface of the first doped layer 103, thereby affecting the stability and reliability of the detector structure and performance. The crystal defect density of the first doped layer 103 is set to within 10-1. 5 ~10 6 cm -2 Within this range, its lattice defect density is low, which can effectively reduce the influence of structural defects such as dislocations, vacancies, and grain boundaries on carrier recombination, thereby reducing the intrinsic dark current of the detector. The first doped layer 103 can be N-type or P-type doped, and its doping concentration can be adjusted according to the detector design requirements, without limitation here. For example, the doping concentration of the first doped layer 103 can be set to 10... 18 ~ 10 19 cm -3 Within this range, the requirements for subsequent detector structure formation and electric field distribution optimization are met.

[0036] Based on the above embodiments, optionally, the thickness of the absorption layer 200 is in the range of 500 ~ 2000 nm.

[0037] Specifically, setting the thickness of the absorption layer 200 within the range of 500 to 2000 nm can improve the detector's light absorption capability, ensure sufficient absorption of short-wave infrared light signals, avoid lattice cracks, improve the detector's quantum efficiency, and optimize the detector's performance. If the thickness of the absorption layer 200 is too large, it may lead to stress and lattice crack problems in the detector; if the thickness of the absorption layer 200 is too small, it may lead to insufficient infrared light absorption capability of the detector, affecting the detector's photoelectric performance.

[0038] Based on the above embodiments, Figure 2 This is a schematic diagram of the structure of another short-wave infrared photodetector provided in an embodiment of the present invention. See also Figure 2Optionally, the short-wave infrared photodetector further includes: a passivation layer 400, a first electrode 501, and a second electrode 502.

[0039] A trench T1 is provided on the second doped layer 300, and the bottom of the trench T1 exposes the first doped layer 103. The passivation layer 400 covers the surface of the second doped layer 300 and the inner wall of the trench T1; The first electrode 501 is electrically connected to the first doped layer 103, and the second electrode 502 is electrically connected to the second doped layer 300.

[0040] Specifically, a trench T1 extends inward from the surface of the second doped layer 300 and into the first doped layer 103. The trench T1 defines the photosensitive area of ​​the detector to control the uniformity of illumination and the internal electric field of the device. A passivation layer 400 is formed over the entire surface of the second doped layer 300, completely covering the surface of the second doped layer 300 and the inner wall of the trench T1. This reduces surface defects and carrier recombination, enabling efficient carrier migration along the desired direction, which is beneficial for improving the photoelectric conversion efficiency and response speed of the detector. Metal electrodes are formed on the surface of the passivation layer 400. Specifically, a first electrode 501 is formed at the bottom of the trench T1 and is electrically connected to the first doped layer 103 through a via. A second electrode 502 is formed on the passivation layer 400 on the surface of the second doped layer 300 between the trenches T1 and is electrically connected to the second doped layer 300 through a via, thereby completing the electrical connection of the vertical PIN structure and realizing the functional application of the photodetector.

[0041] This invention also provides a method for manufacturing a shortwave infrared photodetector. Figure 3 This is a schematic flowchart illustrating a manufacturing method for a shortwave infrared photodetector provided in an embodiment of the present invention. Figures 4 to 5 yes Figure 3 A structural diagram corresponding to each step. See also... Figure 1 , Figures 3 to 5 The manufacturing method of this short-wave infrared photodetector specifically includes the following steps: S110, Provide a substrate structure; the substrate structure includes a silicon substrate, a buried oxide layer and a first doped layer stacked together; the first doped layer is configured as a germanium layer having a first conductivity type.

[0042] Specifically, see Figure 4A substrate structure 100 is provided. The substrate structure 100 includes a silicon substrate 101, a buried oxide layer 102, and a first doped layer 103 stacked together. The first doped layer 103 is configured as a germanium layer having a first conductivity type. A germanium-on-insulator (GOI) wafer is used as the initial substrate, and the germanium layer disposed on the surface of the buried oxide layer 102 is a first doped layer 103 with a first conductivity type. The GOI wafer provides a high-quality, doped germanium layer with high lattice quality, reducing the influence of structural defects such as dislocations, vacancies, and grain boundaries on carrier recombination. The doped germanium layer can form a controlled electric field region, which is beneficial for the efficient migration and collection of carriers, thereby reducing intrinsic dark current and optimizing the detector's response speed and photoelectric conversion efficiency. The buried oxide layer 102 in the GOI wafer effectively blocks the leakage current path between the first doped layer 103 and the silicon substrate 101, reducing carrier recombination and leakage current caused by interface states, and further suppressing the generation of dark current.

[0043] S120. On the side of the first doped layer in the substrate structure away from the buried oxide layer, an intrinsic germanium layer is homoepitaxially grown to form an absorption layer.

[0044] Specifically, see Figure 5 On the side of the first doped layer 103 in the substrate structure 100 away from the buried oxide layer 102, an intrinsic germanium layer is homoepitaxially grown to form an absorption layer 200. Since the first doped layer 103 in the substrate structure 100 is a doped germanium layer, an intrinsic germanium layer can be homoepitaxially grown on the surface of the first doped layer 103 to form the absorption layer 200. Homoepitaxial growth ensures that the absorption layer 200 has high crystal quality and low defect density, avoiding dislocations and lattice defects generated during epitaxy, thereby reducing defect recombination centers and effectively reducing dark current, providing a foundation for achieving high-efficiency photoelectric conversion in the detector. Furthermore, the absorption layer 200 formed by homoepitaxial growth has a high lattice matching degree with the first doped layer 103, low internal stress, and maintains the integrity of the vertical device structure.

[0045] S130. A III-V group material layer is heteroepitaxially grown on the side of the absorption layer away from the substrate structure to form a second doped layer; the second doped layer has a second conductivity type, which is opposite to the first conductivity type.

[0046] Specifically, see [link to relevant documentation] Figure 1A III-V group material layer is heteroepitaxially grown on the side of the absorber layer 200 away from the substrate structure 100 to form a second doped layer 300. The second doped layer 300 has a second conductivity type, which is opposite to the first conductivity type. By setting the conductivity type of the second doped layer 300 to be opposite to that of the first doped layer 103, a vertical PIN structure can be formed, adjusting the band structure of the heterolayer and achieving precise control over the carrier flow direction. Furthermore, the doped III-V group material layer can form a corresponding band structure with the intrinsic germanium absorber layer 200 to block thermally excited carriers and reverse-injected carriers, thereby effectively suppressing the generation of dark current. Introducing a high-quality doped heterolayer, namely the second doped layer 300, can improve the electric field distribution inside the device and enhance the stability of the device under room temperature and long-term operating conditions.

[0047] The manufacturing method of the short-wave infrared photodetector provided in the embodiments of the present invention can manufacture the short-wave infrared photodetector provided in any of the above embodiments of the present invention, and has similar beneficial effects as the short-wave infrared photodetector, which will not be described in detail here.

[0048] Based on the above embodiments, optionally, step S130, which involves heteroepitaxially growing a III-V group material layer on the side of the absorption layer away from the substrate structure to form a second doped layer, specifically includes the following steps: A second doped layer is formed by heteroepitaxial growth of an AlAs or GaAs material layer on the side of the absorption layer away from the substrate structure.

[0049] Specifically, a heteroepitaxial growth of a doped AlAs or GaAs material layer on the absorption layer achieves high lattice matching with the intrinsic germanium absorption layer, enabling high-quality heterolayer growth without introducing significant lattice defects. By using an AlAs or GaAs material layer to form a second doped layer, a significant bandgap difference can be created with the intrinsic germanium absorption layer, effectively blocking thermally excited and reverse-injected carriers, further suppressing dark current generation, and fundamentally improving the detector's signal-to-noise ratio and detectivity.

[0050] Based on the above embodiments, Figure 6 This is a schematic diagram of the specific process of step S110 in the manufacturing method of a shortwave infrared photodetector provided in an embodiment of the present invention. Figure 7 yes Figure 6 A structural diagram corresponding to the relevant steps. See also... Figure 1 , Figures 6 to 7 Optionally, providing the substrate structure in step S110 specifically includes the following steps: S111, Provide a substrate; the substrate includes a silicon substrate, a buried oxide layer and a germanium layer stacked together.

[0051] Specifically, see Figure 7 A substrate 104 is provided; the substrate 104 includes a silicon substrate 101, a buried oxide layer 102 and a germanium layer 105 stacked together.

[0052] S112. Using an ion implantation method, conductive ions of a first conductivity type are implanted into the germanium layer to form a first doped layer.

[0053] Specifically, see [link to relevant documentation] Figure 1 The germanium layer 105 is implanted with conductive ions of a first conductivity type using ion implantation to form a first doped layer 103. The germanium layer 105 is then doped using either ion implantation or diffusion to form a doped region with controllable carrier concentration, i.e., the first doped layer 103. By using ion implantation or diffusion, the doping depth and concentration distribution of the germanium layer 105 can be precisely controlled, ensuring that the crystal quality of the absorption layer 200 is not compromised, while simultaneously enhancing the stability of the detector under room temperature and long-term operating conditions.

[0054] Based on the above embodiments, the manufacturing method of the short-wave infrared photodetector may optionally include the following steps: The second doped layer is etched to form a trench; the bottom of the trench exposes the first doped layer. An insulating material is deposited on the surface of the second doped layer to form a passivation layer; the passivation layer covers the surface of the second doped layer and the inner wall of the trench. Metal material is deposited at the bottom of the trench to form a first electrode, and metal material is deposited on the side of the passivation layer away from the second doped layer to form a second electrode; wherein the first electrode is electrically connected to the first doped layer, and the second electrode is electrically connected to the second doped layer.

[0055] Specifically, after forming the heteroepitaxial layer with the second doped layer, the photodetector structure is fabricated, including etching trenches in the second doped layer to define the photosensitive region and control the uniformity of illumination and the internal electric field of the detector. The detector surface is then passivated by depositing silicon dioxide or other insulating materials across the entire surface to form a passivation layer covering the surface of the second doped layer and the inner walls of the trenches, reducing surface defects and carrier recombination. Vias are etched into the passivation layer at the bottom of the trenches, and metal material is deposited to form the first electrode, which is electrically connected to the first doped layer through the vias. Vias are also etched into the passivation layer between adjacent trenches, and metal material is deposited to form the second electrode, which is electrically connected to the second doped layer through the vias, thus completing the electrical connection of the vertical PIN structure. This ensures the integrity of the detector structure, enables efficient collection of photoelectric signals, and meets the requirements of process repeatability and mass production.

[0056] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A short-wave infrared photodetector, characterized in that, include: The substrate structure includes a silicon substrate, a buried oxide layer, and a first doped layer stacked together; the first doped layer is configured as a germanium layer having a first conductivity type. An absorption layer is disposed on the side of the first doped layer in the substrate structure away from the buried oxide layer; the absorption layer is an intrinsic germanium layer. A second doped layer is disposed on the side of the absorption layer away from the substrate structure; the second doped layer is configured as a III-V group material layer having a second conductivity type. The second conductivity type is the opposite of the first conductivity type.

2. The shortwave infrared photodetector according to claim 1, characterized in that, The first doped layer is a germanium layer of N-type conductivity, and the second doped layer is a III-V material layer of P-type conductivity. Alternatively, the first doped layer may be a germanium layer of P-type conductivity, and the second doped layer may be a III-V material layer of N-type conductivity.

3. The shortwave infrared photodetector according to claim 2, characterized in that, The III-V group material layer includes an AlAs material layer or a GaAs material layer; The thickness of the III-V group material layer ranges from 200 to 300 nm.

4. The shortwave infrared photodetector according to claim 1, characterized in that, The thickness of the first doped layer ranges from 500 to 1000 nm, and the crystal defect density ranges from 10. 5 ~ 10 6 cm -2 The doping concentration range is 10. 18 ~ 10 19 cm -3 .

5. The shortwave infrared photodetector according to claim 1, characterized in that, The thickness of the absorption layer ranges from 500 to 2000 nm.

6. The shortwave infrared photodetector according to claim 1, characterized in that, Also includes: Passivation layer, first electrode and second electrode; The second doped layer has trenches, the bottom of which exposes the first doped layer; The passivation layer covers the surface of the second doped layer and the inner wall of the trench; The first electrode is electrically connected to the first doped layer, and the second electrode is electrically connected to the second doped layer.

7. A method for manufacturing a shortwave infrared photodetector, characterized in that, include: A substrate structure is provided; the substrate structure includes a silicon substrate, a buried oxide layer, and a first doped layer stacked thereon; the first doped layer is configured as a germanium layer having a first conductivity type. On the side of the first doped layer in the substrate structure away from the buried oxide layer, an intrinsic germanium layer is homoepitaxially grown to form an absorption layer. A III-V group material layer is heteroepitaxially grown on the side of the absorption layer away from the substrate structure to form a second doped layer; the second doped layer has a second conductivity type, which is opposite to the first conductivity type.

8. The method for manufacturing a shortwave infrared photodetector according to claim 7, characterized in that, The step of heteroepitaxially growing a III-V group material layer on the side of the absorption layer away from the substrate structure to form a second doped layer includes: A second doped layer is formed by heteroepitaxial growth of an AlAs or GaAs material layer on the side of the absorption layer away from the substrate structure.

9. The method for manufacturing a shortwave infrared photodetector according to claim 7, characterized in that, The provision of the substrate structure includes: A substrate is provided; the substrate includes a silicon substrate, a buried oxide layer, and a germanium layer stacked thereon; The germanium layer is implanted with conductive ions of a first conductivity type using an ion implantation method to form the first doped layer.

10. The method for manufacturing a shortwave infrared photodetector according to claim 7, characterized in that, Also includes: Trenches are formed by etching the second doped layer; The bottom of the trench exposes the first doped layer; An insulating material is deposited on the surface of the second doped layer to form a passivation layer; The passivation layer covers the surface of the second doped layer and the inner wall of the trench; A first electrode is formed by depositing metal material at the bottom of the trench, and a second electrode is formed by depositing metal material on the side of the passivation layer away from the second doped layer; wherein the first electrode is electrically connected to the first doped layer, and the second electrode is electrically connected to the second doped layer.

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