Semiconductor structure and method of forming the same

Abstract

A semiconductor structure and a forming method thereof, the method comprising: providing a substrate, the substrate comprising a photoelectric conversion region; forming a photodetection structure on the top of the substrate of the photoelectric conversion region, the photodetection structure comprising a light absorption layer and a first doped layer in contact with two sides of the light absorption layer, and the first doped layers on the two sides of the light absorption layer are of different doping types; forming a light field limiting layer on the top of the first doped layers on the two sides of the light absorption layer, and the extending direction of the light field limiting layer is the same as that of the first doped layers. The response and bandwidth of the semiconductor structure are improved, and the contradiction between the response and the bandwidth of the semiconductor structure is effectively alleviated.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a semiconductor structure and a method for forming the same. Background Technology

[0002] Photodetectors are devices that convert optical signals into electrical signals and play a crucial role in traditional communication and optical interconnect systems. Currently, silicon-based photodetectors used in communication and interconnect systems are primarily based on PIN (P-Intrinsic-N) structures. Operating bandwidth and responsivity, as two key performance indicators of photodetectors, directly affect the signal transmission and processing capabilities of optical communication and optical interconnect systems.

[0003] The different performance indicators of detectors present many contradictions in their requirements for optical structures, making it difficult to simultaneously meet all requirements. This brings many challenges to the design of their optical structures. Taking responsivity and bandwidth in bulk material detectors as an example, higher responsivity requires a sufficiently large structural size to ensure complete absorption of incident light. However, for large-sized detectors, the transmission of electrical signals takes longer, resulting in a slower response speed.

[0004] Therefore, in actual detector structure design, there is a contradictory relationship between detector responsivity and bandwidth. Summary of the Invention

[0005] The problem solved by the embodiments of the present invention is to provide a semiconductor structure and a method for forming the same, which effectively alleviates the contradiction between the susceptibility and bandwidth of the semiconductor structure and improves the performance of the semiconductor structure.

[0006] To address the aforementioned problems, embodiments of the present invention provide a method for forming a semiconductor structure, comprising: providing a substrate, the substrate including a photoelectric conversion region; forming a photodetector structure on top of the substrate of the photoelectric conversion region, the photodetector structure including a light absorption layer and a first doped layer in contact with both sides of the light absorption layer, wherein the doping types of the first doped layers on both sides of the light absorption layer are different; forming a confining light field layer on top of the first doped layers on both sides of the light absorption layer, wherein the extending direction of the confining light field layer is the same as the extending direction of the first doped layer.

[0007] Accordingly, embodiments of the present invention also provide a semiconductor structure formed using the formation method provided by the present invention, comprising: a substrate, the substrate including a photoelectric conversion region; a photodetector structure located on top of the substrate of the photoelectric conversion region, the photodetector structure including a light absorption layer and a first doped layer in contact with both sides of the light absorption layer, wherein the doping types of the first doped layers on both sides of the light absorption layer are different; and a confining light field layer located on top of the first doped layers on both sides of the light absorption layer, wherein the extending direction of the confining light field layer is the same as the extending direction of the first doped layer.

[0008] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0009] The semiconductor structure formation method provided in this invention involves forming a photodetector structure on top of a substrate. The photodetector structure includes a light-absorbing layer and first doped layers contacting both sides of the light-absorbing layer. The first doped layers on both sides of the light-absorbing layer have different doping types. A confining light field layer is formed on top of the first doped layers on both sides of the light-absorbing layer, and the extension direction of the confining light field layer is the same as the extension direction of the first doped layers. By forming a confining light field layer on top of the first doped layers on both sides of the light-absorbing layer, this invention can confine incident light to the region above the light-absorbing layer. Correspondingly, while further reducing the size of the light-absorbing layer, it can also reduce the probability of light scattering loss, allowing the light-absorbing layer to fully absorb the incident light signal. This enables the photodetector structure to convert the incident light signal into an electrical signal, improving the quantum efficiency of the semiconductor structure. This, in turn, improves both the responsivity and bandwidth of the semiconductor structure, effectively alleviating the contradiction between responsivity and bandwidth, and thus improving the performance of the semiconductor structure.

[0010] The semiconductor structure provided in this embodiment of the invention includes a photodetector structure located on top of a substrate. The photodetector structure comprises a light-absorbing layer and first doped layers contacting both sides of the light-absorbing layer. The first doped layers on both sides of the light-absorbing layer have different doping types. A confining light field layer is located on top of the first doped layers on both sides of the light-absorbing layer, and the extension direction of the confining light field layer is the same as the extension direction of the first doped layers. By setting the confining light field layer on top of the first doped layers on both sides of the light-absorbing layer, the confining light field layer can confine the incident light to the region above the light-absorbing layer. Correspondingly, while further reducing the size of the light-absorbing layer, it can also reduce the probability of light scattering loss of the incident light. This reduces the probability of light scattering loss, allowing the light-absorbing layer to fully absorb the incident light signal, enabling the photodetector structure to convert the incident light signal into an electrical signal. This improves the quantum efficiency of the semiconductor structure, thereby increasing both the responsivity and bandwidth of the semiconductor structure, effectively alleviating the contradiction between responsivity and bandwidth, and ultimately improving the performance of the semiconductor structure. Attached Figure Description

[0011] Figures 1 to 19 The diagram shows a schematic representation of the structure corresponding to each step in the first embodiment of the semiconductor structure formation method of the present invention.

[0012] Figures 20 to 26 A schematic diagram of the structure corresponding to each step in the second embodiment of the method for forming a semiconductor structure of the present invention is shown.

[0013] Figures 27 to 30 The diagram shows the structural schematics corresponding to each step in the third embodiment of the semiconductor structure formation method of the present invention;

[0014] Figures 31 to 32 A schematic diagram of one embodiment of the semiconductor structure of the present invention is shown. Detailed Implementation

[0015] As the background technology shows, the high responsivity of current photodetectors requires a sufficiently large structural size to ensure complete absorption of incident light. However, for larger detectors, the transmission time of electrical signals is longer, resulting in a slower response speed. Therefore, there is a trade-off between the responsivity and bandwidth of the detector.

[0016] To address the technical problem, embodiments of the present invention provide a method for forming a semiconductor structure, comprising: providing a substrate; forming a photodetector structure on top of the substrate, the photodetector structure including a light absorption layer and a first doped layer in contact with both sides of the light absorption layer, wherein the doping types of the first doped layers on both sides of the light absorption layer are different; forming a confining light field layer on top of the first doped layers on both sides of the light absorption layer, wherein the extension direction of the confining light field layer is the same as the extension direction of the first doped layer.

[0017] The semiconductor structure formation method provided in this invention involves forming a photodetector structure on top of a substrate. The photodetector structure includes a light-absorbing layer and first doped layers contacting both sides of the light-absorbing layer. The first doped layers on both sides of the light-absorbing layer have different doping types. A confining light field layer is formed on top of the first doped layers on both sides of the light-absorbing layer, and the extension direction of the confining light field layer is the same as the extension direction of the first doped layers. By forming a confining light field layer on top of the first doped layers on both sides of the light-absorbing layer, this invention confines incident light to the region above the light-absorbing layer. Correspondingly, while further reducing the size of the light-absorbing layer, it also reduces the probability of light scattering loss. This reduces the probability of light scattering loss, allowing the light-absorbing layer to fully absorb the incident light signal. This enables the photodetector structure to convert the incident light signal into an electrical signal, improving the quantum efficiency of the semiconductor structure. This, in turn, increases the responsivity and bandwidth of the semiconductor structure, effectively alleviating the contradiction between responsivity and bandwidth, and ultimately improving the performance of the semiconductor structure.

[0018] To make the above-mentioned objects, features, and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Among them, Figures 1 to 19 The diagram shows the structural schematics corresponding to each step in the first embodiment of the semiconductor structure formation method of the present invention.

[0019] refer to Figures 1 to 2 ,in, Figure 1 It is a top view. Figure 2 Tie Figure 1 A cross-sectional view along the AA direction provides a substrate 102, which includes a photoelectric conversion region 100A.

[0020] Specifically, the substrate 102 provides a process platform for the subsequent formation of photoelectric detection structures.

[0021] Among them, the photoelectric conversion region 100A is the region that converts the input optical signal into an electrical signal. Under reverse bias, the electron-hole pairs generated by the photons are swept out of the depletion region by the electric field, generating a photocurrent.

[0022] In this embodiment, the substrate 102 includes a bottom insulating layer 100 and a substrate 101 located on top of the bottom insulating layer 100.

[0023] Specifically, the bottom insulating layer 100 is used to electrically isolate the subsequently formed photodetector structure from other transistors below the bottom insulating layer 100, which can reduce the parasitic capacitance of the semiconductor structure and help improve the responsivity and bandwidth of the photodetector structure.

[0024] It should be noted that, as an example, substrate 101 provides a process platform for the subsequent formation of an electrical probe structure. In other embodiments, substrate 101 also provides a process basis for the subsequent formation of a first doped region, wherein the first doped region is located within substrate 101.

[0025] In this embodiment, the substrate 102 further includes an optical waveguide region 100B, and an optical waveguide layer is formed in the substrate 102 of the optical waveguide region 100B.

[0026] Specifically, the optical waveguide layer in the optical waveguide region 100B is used to guide the incident optical signal to the photoelectric detection structure in the photoelectric conversion region 100A, so that the photoelectric detection structure can convert the input optical signal into an electrical signal.

[0027] As an example, a substrate 101 is also formed in the optical waveguide region 100B, and the substrate 101 in the optical waveguide region 100B is used as an optical waveguide layer.

[0028] It should be noted that the substrate 101 in the optical waveguide region 100B and the substrate 101 in the photoelectric conversion region 100A are an integral structure, which can improve the flatness of the entire substrate 101 and reduce the difficulty of subsequent photoelectric detection structure formation.

[0029] refer to Figures 3 to 14 A photodetector structure is formed on top of the substrate 102 of the photoelectric conversion region 100A. The photodetector structure includes a light absorption layer 199 and a first doped layer 118 in contact with both sides of the light absorption layer 199, and the doping types of the first doped layers 118 on both sides of the light absorption layer 199 are different.

[0030] Specifically, the photodetector structure is used to convert optical signals into electrical signals. The light absorption layer 199 has a high electron mobility and is used to absorb incident light signals. The first doped layers 118 on both sides of the light absorption layer 199 have different doping types, so that the first doped layers 118 on both sides of the light absorption layer 199 and the light absorption layer 199 can form a PIN photodetector structure. Correspondingly, under reverse bias, the light absorption layer 199 will form a depletion region. The electron-hole pairs generated by the photons absorbed by the light absorption layer 199 are swept out of the depletion region by the electric field, thereby generating photocurrent.

[0031] As an example, the first doped layer 118 on one side of the light absorption layer 199 is P-type doped, and the first doped layer 118 on the other side of the light absorption layer 199 is N-type doped.

[0032] Reference Figures 3 to 14 The steps for forming the photoelectric detection structure are explained in detail.

[0033] refer to Figure 3A first dielectric layer 104 is formed on top of the bottom insulating layer 100 and the substrate 101.

[0034] Specifically, the first dielectric layer 104 provides the technological basis for the subsequent formation of the light-absorbing material layer 110. At the same time, the first dielectric layer 104 also provides electrical isolation for adjacent photodetector structures, reducing the risk of leakage current between adjacent photodetector structures.

[0035] As an example, the steps of forming the first dielectric layer 104 include: a first dielectric material layer on top of the bottom insulating layer 100 and the substrate 101; and planarizing the first dielectric material layer to form the first dielectric layer 104.

[0036] In this embodiment, the material of the first dielectric layer 104 includes one or more of silicon oxide, silicon nitride, and silicon oxynitride.

[0037] refer to Figure 4 A light-absorbing material layer 110 is formed in a first dielectric layer 104 on top of the substrate 101, with the first dielectric layer 104 exposing the top surface of the light-absorbing material layer 110.

[0038] Specifically, the light-absorbing material layer 110 is used as the material layer for the subsequent formation of the light-absorbing layer 199. At the same time, the two ends of the light-absorbing material layer 110 also occupy space in advance for the subsequent formation of the first doped layer 118. During the subsequent formation of the first doped layer 118, there is an etching selectivity between the light-absorbing material layer 110 and the first dielectric layer 104. This allows the two ends of the light-absorbing material layer 110 to be removed while ensuring the sidewall morphology quality of the first dielectric layer 104, thus reducing the deposition difficulty of forming the first doped layer 118.

[0039] As an example, the step of forming a light-absorbing material layer 110 in the first dielectric layer 104 on top of the substrate 101 includes: forming a first groove (not shown) in the first dielectric layer 104 on top of the substrate 101, the first groove exposing a portion of the top surface of the substrate 101; forming a light-absorbing material layer 110 on top of the first dielectric layer 104 and in the first groove; and planarizing the light-absorbing material layer 110 above the top of the first dielectric layer 104.

[0040] In this embodiment, the process for forming the first groove includes a dry etching process.

[0041] Specifically, the dry etching process is an anisotropic dry etching process, with a longitudinal etching rate much greater than the transverse etching rate, resulting in higher pattern transfer accuracy. This ensures the morphological quality of the first groove sidewall. Correspondingly, in the subsequent formation of the first doped layer 118, the deposition process of the first doped layer 118 can reduce the probability of a void between the first doped layer 118 and the light absorption layer 199, thereby reducing the probability that the PIN of the photodetector structure cannot convert the optical signal into an electrical signal and improving the robustness of the semiconductor structure.

[0042] In this embodiment, the process for forming the light-absorbing material layer 110 includes a selective deposition process.

[0043] As an example, planarization processes include chemical mechanical polishing.

[0044] In this embodiment, the material of the light-absorbing material layer 110 includes germanium.

[0045] Specifically, germanium has a high electron mobility, enabling it to absorb light in the near-infrared communication band, making it fully compatible with CMOS technology. Furthermore, germanium has high light absorption efficiency, which can improve the quantum efficiency of photoelectric detection structures.

[0046] refer to Figures 5 to 14 The end of the light-absorbing material layer 110 is patterned to form a plurality of openings 114 formed by the sidewall of the first dielectric layer 104, the top surface of the substrate 101, and the remaining sidewall of the light-absorbing material layer 110, and the remaining light-absorbing material layer 110 is used as a light-absorbing layer 199; a first doped layer 118 is formed in the openings to contact the light-absorbing layer 199, and the light-absorbing layer 199 and the first doped layer 118 contacting both sides of the light-absorbing layer 199 constitute a photoelectric detection structure.

[0047] It should be noted that the light absorption layer 199 has a high electron mobility and is used to absorb incident light signals. The first doped layers 118 on both sides of the light absorption layer 199 have different doping types, which enables the first doped layers 118 on both sides of the light absorption layer 199 and the light absorption layer 199 to form a PIN photodetector structure. Correspondingly, under reverse bias, the light absorption layer 199 will form a depletion region. The electron-hole pairs generated by the photons absorbed by the light absorption layer 199 are swept out of the depletion region by the electric field, thereby generating photocurrent.

[0048] like Figures 5 to 14As shown, the step of patterning the end of the light-absorbing material layer 110 to form the opening, and forming the first doped layer 118 in the opening 114 includes: patterning one end of the light-absorbing material layer 110 to form a first opening 197 surrounded by the sidewall of the first dielectric layer 104, the top surface of the substrate 101, and the remaining sidewall of the light-absorbing material layer 110; forming the first doped layer 118 on the sidewall and bottom of the first opening 197; after forming the first doped layer 118, The other end of the light-absorbing material layer 110 is patterned to form a second opening 198 surrounded by the sidewall of the first dielectric layer 104, the top surface of the substrate 101, and the remaining sidewall of the light-absorbing material layer 110, and the remaining light-absorbing material layer 110 is used as a light-absorbing layer 199; a first doped layer 118 is formed on the sidewall and bottom of the second opening 198, and the light-absorbing layer 199 and the first doped layer 118 in contact with both sides of the light-absorbing layer 199 constitute a photoelectric detection structure.

[0049] Specifically, the first opening 197 and the second opening 198 provide spatial locations for the subsequent formation of the first doped layer 118.

[0050] It should be noted that by forming the first opening 197 first and then the second opening 198, the process window for forming the first opening 197 and the second opening 198 can be increased, and the process difficulty of forming the first opening 197 and the second opening 198 can be reduced.

[0051] It should also be noted that, compared to the approach of forming the first doped layer 118 first and then the light-absorbing layer 199, this approach forms the light-absorbing layer 199 after the first doped layer 118, increasing the aspect ratio between the first doped layers 118 and thus increasing the difficulty of forming the light-absorbing layer 199. In contrast, this embodiment forms the light-absorbing material layer first, then the first opening 197 and the second opening 198, and then uses the remaining light-absorbing material layer as the light-absorbing layer. This increases the process window for forming the light-absorbing material layer, resulting in higher formation quality and reduced process difficulty. Consequently, after forming the first opening 197 and the second opening 198, the formation quality of the light-absorbing layer is also high.

[0052] As an example, the step of patterning one end of the light-absorbing material layer 110 includes: as follows Figure 5 As shown, a patterned first mask layer 112 is formed on top of the first dielectric layer 104 and the light-absorbing material layer 110, with the first mask layer 112 exposing one end of the light-absorbing material layer 110; as Figure 6As shown, using the first mask layer 112 as a mask, the exposed light-absorbing material layer 110 is patterned to form a first opening 197 surrounded by the sidewall of the first dielectric layer 104, the top surface of the substrate 101, and the remaining sidewall of the light-absorbing material layer 110.

[0053] In this embodiment, the material of the first mask layer 112 includes silicon nitride.

[0054] As an example, the process for patterning the exposed light-absorbing material layer 110 includes a dry etching process.

[0055] In this embodiment, the step of forming a first doped layer 118 on the sidewall and bottom of the first opening 197 includes: as follows Figure 7 As shown, a first doped material layer 111 is formed on the top of the first dielectric layer 104, the top of the light-absorbing material layer 110, the sidewall of the first opening 197, and the bottom; as Figures 8 to 9 As shown, the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110 is removed, and the remaining first doped material layer 111 located on the sidewall and bottom of the first opening 197 is used as the first doped layer 118.

[0056] Specifically, removing the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110 exposes the top of the first mask layer 112, which facilitates the formation of the second opening 198 in subsequent patterning processes.

[0057] In this embodiment, the process of forming the first doped layer 118 on the sidewall and bottom of the first opening 197 includes an in-situ doping deposition process.

[0058] It should be noted that, compared to the method of performing ion implantation on the in-situ layer after deposition, the in-situ doping deposition process in this embodiment directly incorporates impurities during the deposition of the in-situ layer. This method can improve the uniformity and precision of doping. By performing doping simultaneously during the deposition of the in-situ layer, the synchronous deposition of dopant ions and the in-situ layer is achieved, avoiding the probability of dopant ions being implanted into the substrate 101, thereby overcoming the difficulty of precise control in traditional step-by-step doping.

[0059] As an example, the material of the in-situ layer includes silicon.

[0060] In this embodiment, P-type ions are doped while depositing silicon material, so that the first doped layer 118 is a P-type region.

[0061] like Figures 8 to 9As shown, after forming the first doped material layer 111 in the first opening 197 and before subsequently removing the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110, the formation method further includes forming a second dielectric layer 117 in the remaining space of the first opening 197.

[0062] It should be noted that by forming a second dielectric layer 117 in the remaining space of the first opening 197, the second dielectric layer 117 can fill the remaining space of the first opening 197, making the top of the second dielectric layer 117 flush with the top of the first doped layer 118. Correspondingly, in the subsequent process of forming the first doped layer 118 in the second opening 198, the probability of the first doped layer 118 formed in the second opening 198 contacting the first doped layer 118 in the first opening 197 is reduced, thereby enabling the formation of first doped layers 118 with different doping types on both sides of the light absorption layer.

[0063] In this embodiment, the step of forming the second dielectric layer 117 includes: as follows Figure 8 As shown, a second dielectric material layer 116 is formed in the remaining space of the second opening 198 and on top of the first doped material layer 111; as Figure 9 As shown, the second dielectric material layer 116 on top of the first doped material layer 111 is removed, and the remaining second dielectric material layer 116 located in the second opening 198 is used as the second dielectric layer 117.

[0064] As an example, in the same step, the second dielectric material layer 116 on top of the first doped material layer 111 is removed, as well as the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110 is removed.

[0065] It should be noted that removing the second dielectric material layer 116 on top of the first doped material layer 111 and removing the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110 in the same step can reduce the number of process steps and reduce process costs.

[0066] In other embodiments, the second dielectric material layer on top of the first doped material layer and the first doped material layer on top of the first dielectric layer and the light-absorbing material layer can also be removed in different steps.

[0067] In this embodiment, the steps of removing the second dielectric material layer 116 on top of the first doped material layer 111 and removing the first doped material layer 111 on top of the first dielectric layer 104 and the light-absorbing material layer 110 include: taking the top of the first mask layer 112 as the stop position, performing planarization processing on the second dielectric material layer 116 and the first doped material layer 111 that are higher than the top of the first mask layer 112.

[0068] Specifically, the process of planarizing the second dielectric material layer 116 and the first doped material layer 111, which are above the top of the first mask layer 112, includes a chemical mechanical polishing process.

[0069] like Figures 10 to 11 As shown, in this embodiment, the step of patterning the other end of the light-absorbing material layer 110 includes: patterning the first mask layer 112 above the other end of the light-absorbing material layer 110 to expose the other end of the light-absorbing material layer 110; using the remaining first mask layer 112 as a mask, patterning the exposed light-absorbing material layer 110 to form a second opening 198 surrounded by the sidewall of the first dielectric layer 104, the top surface of the substrate 101, and the remaining sidewall of the light-absorbing material layer 110.

[0070] like Figures 12 to 14 As shown, the step of forming a first doped layer 118 on the sidewall and bottom of the second opening 198 includes: forming a first doped material layer 111 on the top of the first dielectric layer 104, the top of the light absorption layer 199, the sidewall and bottom of the second opening 198; removing the first doped material layer 111 on the top of the first dielectric layer 104 and the light absorption layer 199, and using the remaining first doped material layer 111 located on the sidewall and bottom of the second opening 198 as the first doped layer 118.

[0071] In this embodiment, the process of forming the first doped layer 118 on the sidewall and bottom of the second opening 198 includes an in-situ doping deposition process.

[0072] It should be noted that, compared to the method of performing ion implantation on the in-situ layer after deposition, the in-situ doping deposition process in this embodiment directly incorporates impurities during the deposition of the in-situ layer. This method can improve the uniformity and precision of doping. By performing doping simultaneously during the deposition of the in-situ layer, the synchronous deposition of dopant ions and the in-situ layer is achieved, avoiding the probability of dopant ions being implanted into the substrate 101, thereby overcoming the difficulty of precise control in traditional step-by-step doping.

[0073] As an example, the material of the in-situ layer includes silicon.

[0074] In this embodiment, N-type ions are doped while depositing silicon material, so that the first doped layer 118 is an N-type region.

[0075] refer to Figures 13 to 14After forming a first doped material layer 111 on the top of the first dielectric layer 104, the top of the light absorption layer 199, the sidewalls and bottom of the second opening 198, before removing the first doped material layer 111 on the top of the first dielectric layer 104 and the light absorption layer 199, the formation method further includes forming a third dielectric layer 170 in the remaining space of the second opening 198.

[0076] Specifically, the third dielectric layer 170 is used to fill the remaining space of the second opening 198, so that the top of the third dielectric layer 170 is flush with the top of the first doped layer 118, providing a better flat surface for the subsequent semiconductor structure formation steps.

[0077] In this embodiment, during the step of forming the photodetector structure, the photodetector structure is located above the side of the optical waveguide layer, and the extension direction of the photodetector structure and the optical waveguide layer is located in the optical signal transmission direction.

[0078] Specifically, the photodetector structure is located above the side of the optical waveguide layer, and the extension direction of the photodetector structure and the optical waveguide layer is located in the optical signal transmission direction, so that the optical waveguide layer can guide the incident light signal to the photodetector structure in the photoelectric conversion region 100A, and the photodetector structure can convert the input light signal into an electrical signal.

[0079] refer to Figures 15 to 19 ,in, Figure 18 It is a top view. Figure 19 yes Figure 18 In a cross-sectional view along the AA direction, a confining light field layer 181 is formed on top of the first doped layer 118 on both sides of the light absorption layer 199, and the extending direction of the confining light field layer 181 is the same as the extending direction of the first doped layer 118.

[0080] It should be noted that by forming a confined light field layer 181 on top of the first doped layers 118 on both sides of the light absorption layer 199, when light waves irradiate the surface of the confined light field layer 181, photons couple with the free electrons on the surface of the confined light field layer 181, causing the free electrons to oscillate collectively, thereby forming surface plasmon polaritons (SPPs). The surface plasmon polaritons can confine the light energy within the region of the confined light field layer 181, that is, the confined light field layer 181 can confine the incident light to the region above the light absorption layer 199. Correspondingly, while further reducing the size of the light absorption layer 199, the probability of light scattering loss of the incident light can also be reduced. Reducing the probability of light scattering loss of the incident light allows the light absorption layer 199 to fully absorb the incident light signal, enabling the photodetector structure to convert the incident light signal into an electrical signal, thereby improving the quantum efficiency of the semiconductor structure. This improves both the responsivity and bandwidth of the semiconductor structure, effectively alleviating the contradiction between the responsivity and bandwidth of the semiconductor structure, and thus improving the performance of the semiconductor structure.

[0081] In this embodiment, the step of forming the confined light field layer 181 includes: as follows Figure 15 As shown, a fourth dielectric layer 160 covering the photodetector structure is formed on top of the substrate 102; as Figure 16 As shown, the top portion of the fourth dielectric layer 160 of the first doped layer 118 is removed, and a third groove 195 is formed in the fourth dielectric layer 160; as Figures 17 to 19 As shown, a light field confinement layer 181 is formed in the third groove 195.

[0082] Specifically, the fourth dielectric layer 160 provides the technological basis for forming the confined light field layer 181, and the third groove 195 is located on top of the first doped layer 118, so that the confined light field layer 181 in the fourth dielectric layer 160 can confine the incident light to the region above the light absorption layer 199. Accordingly, while further reducing the size of the light absorption layer 199, the probability of light scattering loss of the incident light can also be reduced.

[0083] As an example, the step of forming the confining light field layer 181 in the third groove 195 includes: forming a confining light field material layer 180 on top of the fourth dielectric layer 160 and in the third groove 195; taking the top of the fourth dielectric layer 160 as the stop position, performing planarization processing on the confining light field material layer 180 above the top of the fourth dielectric layer 160, and using the remaining confining light field material layer 180 located in the third groove 195 as the confining light field layer 181.

[0084] Specifically, the shape of the confining light field layer 181 includes one or more of the following: rectangular, trapezoidal, elliptical, and triangular. The rectangular, trapezoidal, elliptical, and triangular confining plaza layers 181 are formed on top of the first doped layer 118. The opposing confining plaza layers 181 can form a slit for incident light above the light absorption layer 199, confining the incident light to the region above the light absorption layer 199, so that the light absorption layer 199 can fully absorb the incident light signal.

[0085] As an example, Figure 18 The shape of the confined light field layer 181 is trapezoidal.

[0086] In this embodiment, the material of the light field confinement layer 181 includes noble metals.

[0087] Specifically, noble metals have a high density of free electrons, which can effectively support the excitation and propagation of surface plasmas.

[0088] In this embodiment, the material of the light field confinement layer 181 includes one or both of copper and gold.

[0089] Specifically, the surface plasmon resonance characteristics of copper and gold exhibit significant light field enhancement and localization effects within a specific wavelength range. Surface plasmon polaritons propagate along the interface between the metal and the medium, and their electric field decays exponentially in both the metal and the medium. This characteristic allows SPP to confine light energy within a nanoscale region, breaking through the diffraction limit of traditional optics. Copper and gold can overcome the optical diffraction limit, thereby confining the incident light to the region above the light absorption layer 199, reducing the probability of light scattering loss, and enabling the light absorption layer 199 to fully absorb the incident light signal, thus improving the quantum efficiency of the photoelectric detection structure.

[0090] It should be noted that the thickness of the light-restricting layer 181 should not be too large or too small. If the thickness of the light-restricting layer 181 is too large, it can easily lead to a weakening of the near-field intensity of surface plasmon polaritons and a reduction in coupling efficiency; if the thickness of the light-restricting layer 181 is too small, it will be difficult for the light-restricting layer 181 to confine the incident light to the region above the light-absorbing layer 199, thereby increasing the probability of light scattering loss of the incident light. Therefore, in this embodiment, the thickness of the light-restricting layer 181 is between 50 micrometers and 300 micrometers.

[0091] It should also be noted that, taking the direction of extension of the light-restricting layer 181, which is parallel to the surface of the substrate and perpendicular to the direction of extension, as the lateral direction, the lateral dimension of the light-restricting layer 181 should not be too large or too small. If the lateral dimension of the light-restricting layer 181 is too large, it compresses the process window for subsequently forming interconnect vias electrically connected to the first doped layer, increasing the difficulty of forming interconnect vias; if the lateral dimension of the light-restricting layer 181 is too small, it makes it difficult for the light-restricting layer 181 to confine the incident light to the region above the light-absorbing layer 199, correspondingly increasing the probability of light scattering loss of the incident light. Therefore, in this embodiment, taking the direction of extension of the light-restricting layer 181, which is parallel to the surface of the substrate and perpendicular to the direction of extension, as the lateral direction, the lateral dimension of the light-restricting layer 181 is 100 micrometers to 500 micrometers.

[0092] As an example, in the step of forming the confined light field layer 181, the confined light field layer 181 is also formed on top of the optical waveguide layer.

[0093] It should be noted that forming a confining optical field layer 181 at the top of the optical waveguide layer can improve the coupling efficiency from the optical waveguide region 100B to the photoelectric conversion region 100A. This is because the confining optical field layer 181 can enhance the interaction between the incident light and the light absorption layer 199. The subwavelength confining capability of surface plasmon polaritons (SPP) is used to enhance the interaction between the incident light and the light absorption layer 199, thereby improving the light absorption efficiency and overall performance, and thus improving the coupling efficiency from the optical waveguide region 100B to the photoelectric conversion region 100A.

[0094] Figures 20 to 26 The diagram shows the structural schematics corresponding to each step in the second embodiment of the semiconductor structure formation method of the present invention.

[0095] The similarities between the embodiments of the present invention and the first embodiment will not be repeated here. The differences between the embodiments of the present invention and the first embodiment are as follows:

[0096] refer to Figures 20 to 26 The steps for forming the photodetector structure include: performing ion implantation on the substrate 201 to form adjacent first doped layers 210 in the substrate 201, with the top surface of the first doped layers 210 exposed; removing a portion of the thickness of the substrate 201 between the adjacent first doped layers 210; and forming a light absorption layer 270 on the top of the remaining substrate 201, wherein the light absorption layer 270 and the first doped layers 210 constitute the photodetector structure.

[0097] Specifically, removing a portion of the thickness of the substrate 201 between adjacent first doped layers 210 facilitates the contact between the sidewalls of the light-absorbing layer 270 subsequently formed on top of the substrate 201 and the first doped layer 210, thereby enabling the light-absorbing layer 270 and the first doped layer 210 twice with the light-absorbing layer 270 to form a PIN.

[0098] In this embodiment, the step of removing a portion of the substrate 201 thickness between adjacent first doped layers 210 includes: as follows Figure 23 As shown, a second dielectric layer 220 is formed on top of the substrate 201 and on top of the first doped layer 210; as Figure 24 As shown, the second dielectric layer 220 above the substrate 201 between adjacent first doped layers 210 is removed, exposing the second groove 260 on the top surface of the substrate 201; as Figure 25 As shown, using the remaining second dielectric layer 220 as a mask, a portion of the thickness of the substrate 201 is removed along the second groove 260.

[0099] In this embodiment, the process of removing a portion of the thickness of the substrate 201 along the second groove 260 using the remaining second dielectric layer 220 as a mask includes a dry etching process.

[0100] In this embodiment, the step of forming a light-absorbing layer 270 on the top of the remaining substrate 201 includes: forming a light-absorbing material layer (not shown) on the top of the second dielectric layer 220 and in the second groove 260; taking the top of the second dielectric layer 220 as the stop position, performing planarization on the light-absorbing material layer above the top of the second dielectric layer 220, and using the remaining light-absorbing material layer located in the second groove 260 as the light-absorbing layer 270.

[0101] In this embodiment, as Figures 21 to 22 As shown, the step of performing ion implantation on the substrate 201 to form adjacent first doped layers 210 in the substrate 201 includes: performing ion implantation on both ends of the substrate 201 to form the first doped layers 210.

[0102] refer to Figure 23 After forming an adjacent first doped layer 210 in the substrate 201 and before forming a light absorption layer 270 thereafter, the formation method further includes: forming a first contact layer 230 of the same doping type in the first doped layer 210, and the first doped layer 210 exposing the top surface of the first contact layer 230.

[0103] Specifically, the first contact layer 230 is used to electrically connect with the subsequently formed plug (CT), thereby enabling the first doped layer 210 to electrically connect with the plug and enabling the first contact layer 230 to reduce the ohmic contact of the plug.

[0104] In this embodiment, the process of forming a first contact layer 230 with the same doping type in the first doped layer 210 includes an ion implantation process.

[0105] As an example, the doping concentration of the first contact layer 230 is greater than that of the first doped layer 210, thereby reducing the ohmic contact between the plug and the first doped layer 210.

[0106] Figures 27 to 30 The diagram shows the structural schematics corresponding to each step in the third embodiment of the semiconductor structure formation method of the present invention.

[0107] The similarities between the embodiments of the present invention and the first embodiment will not be repeated here. The differences between the embodiments of the present invention and the first embodiment are as follows:

[0108] refer to Figures 27 to 30 The step of forming the confined light field layer 311 includes: forming a fourth dielectric layer 300 covering the photodetector structure on the top of the substrate 360; forming a second mask layer 301 having a first mask opening 302 on the top of the fourth dielectric layer 300, the first mask opening 302 being located above the first doped layer 318; and forming the confined light field layer 311 in the first mask opening 302.

[0109] Specifically, a confining light field layer 311 is formed on top of the first doped layer 318 on both sides of the light absorption layer. The confining light field layer 311 can confine the incident light to the region above the light absorption layer, reducing the probability of light scattering loss of the incident light. This allows the light absorption layer to fully absorb the incident light signal, enabling the photodetector structure to convert the incident light signal into an electrical signal. This improves the quantum efficiency of the semiconductor structure, thereby increasing both the responsivity and bandwidth of the semiconductor structure. This effectively alleviates the contradiction between the responsivity and bandwidth of the semiconductor structure, and thus improves the performance of the semiconductor structure.

[0110] As an example, the step of forming a confining light field layer 311 in the first mask opening 302 includes: forming a confining light field material layer 310 on top of the second mask layer 301 and in the first mask opening 302; removing the second mask layer 301 and the confining light field material layer 310 on top of the fourth dielectric layer 300, and using the remaining confining light field material layer 310 located above the first doped layer 318 as the confining light field layer 311.

[0111] Specifically, a confining light field layer 311 is formed on top of the first doped layer 318 on both sides of the light absorption layer. The confining light field layer 311 can confine the incident light to the region above the light absorption layer, reducing the probability of light scattering loss of the incident light. This allows the light absorption layer to fully absorb the incident light signal, enabling the photodetector structure to convert the incident light signal into an electrical signal. This improves the quantum efficiency of the semiconductor structure, thereby increasing both the responsivity and bandwidth of the semiconductor structure. This effectively alleviates the contradiction between the responsivity and bandwidth of the semiconductor structure, and thus improves the performance of the semiconductor structure.

[0112] In this embodiment, the process of removing the second mask layer 301 and the light field limiting material layer 310 on top of the fourth dielectric layer 300 includes an adhesive peeling process.

[0113] Accordingly, embodiments of the present invention also provide a semiconductor structure formed using the formation method provided by the present invention. Wherein, Figures 31 to 32 A schematic diagram of a semiconductor structure according to an embodiment of the present invention is shown. Figure 31 It is a top view. Figure 32 (a) is Figure 31 A cross-sectional view of a photoelectric detection structure along the AA direction. Figure 32 (b) is Figure 31 A cross-sectional view of another photoelectric detection structure along the AA direction.

[0114] The semiconductor structure includes: a substrate 402, the substrate 402 including a photoelectric conversion region 400A; a photodetector structure located on top of the substrate 402 of the photoelectric conversion region 400A, the photodetector structure including a light absorption layer 499 and a first doped layer 418 in contact with both sides of the light absorption layer 499, and the doping types of the first doped layers 418 on both sides of the light absorption layer 499 are different; and a confining light field layer 478 located on top of the first doped layers 418 on both sides of the light absorption layer 499, and the extending direction of the confining light field layer 478 is the same as the extending direction of the first doped layer 418.

[0115] Specifically, by setting a confining light field layer 478 on top of the first doped layers 418 on both sides of the light absorption layer 499, when light waves irradiate the surface of the confining light field layer 478, photons couple with the free electrons on the surface of the confining light field layer 478, causing the free electrons to oscillate collectively, thereby forming surface plasmon polaritons (SPPs). The surface plasmon polaritons can confine the light energy within the region of the confining light field layer 478, that is, the confining light field layer 478 can confine the incident light to the region above the light absorption layer 499. Correspondingly, while further reducing the size of the light absorption layer 499, the probability of light scattering loss of the incident light can also be reduced. Reducing the probability of light scattering loss of the incident light allows the light absorption layer 499 to fully absorb the incident light signal, enabling the photodetector structure to convert the incident light signal into an electrical signal, thereby improving the quantum efficiency of the semiconductor structure. This improves both the responsivity and bandwidth of the semiconductor structure, effectively alleviating the contradiction between the responsivity and bandwidth of the semiconductor structure, and thus improving the performance of the semiconductor structure.

[0116] Substrate 402 provides a process platform for setting up photoelectric detection structures.

[0117] The photoelectric conversion region 400A is the region that converts the input optical signal into an electrical signal. Under reverse bias, the electron-hole pairs generated by the photons are swept out of the depletion region by the electric field, generating a photocurrent.

[0118] In this embodiment, the substrate 402 includes a bottom insulating layer 400 and a substrate 401 located on top of the bottom insulating layer 400.

[0119] Specifically, the bottom insulating layer 400 is used to electrically isolate the subsequently formed photodetector structure from other transistors below the bottom insulating layer 400, which can reduce the parasitic capacitance of the semiconductor structure and help improve the responsivity and bandwidth of the photodetector structure.

[0120] It should be noted that, as an example, substrate 401 provides a process platform for the subsequent formation of an electrical detection structure. In other embodiments, substrate 401 also provides a process basis for setting a first doped region, wherein the first doped region is located within substrate 401.

[0121] As an example, the substrate 402 also includes an optical waveguide region 400B.

[0122] Specifically, the optical waveguide region 400B is used to guide the incident optical signal to the photoelectric detection structure of the photoelectric conversion region 400A, so that the photoelectric detection structure can convert the input optical signal into an electrical signal.

[0123] In this embodiment, the semiconductor structure further includes an optical waveguide layer located in the substrate 402 of the optical waveguide region 400B, and the photodetector structure and the extension direction of the optical waveguide layer are located in the optical signal transmission direction.

[0124] As an example, substrate 401 is also formed in the optical waveguide region 400B, and substrate 401 in the optical waveguide region 400B is used as an optical waveguide layer.

[0125] It should be noted that the substrate 401 in the optical waveguide region 400B and the substrate 401 in the photoelectric conversion region 400A are an integral structure, which can improve the flatness of the entire substrate 401.

[0126] Specifically, the photodetector structure is used to convert optical signals into electrical signals. The light absorption layer 499 has a high electron mobility and is used to absorb incident light signals. The first doped layers 418 on both sides of the light absorption layer 499 have different doping types, so that the first doped layers 418 on both sides of the light absorption layer 499 and the light absorption layer 499 can form a PIN photodetector structure. Correspondingly, under reverse bias, the light absorption layer 499 will form a depletion region. The electron-hole pairs generated by the photons absorbed by the light absorption layer 499 are swept out of the depletion region by the electric field, thereby generating photocurrent.

[0127] As an example, the first doped layer 418 on one side of the light absorption layer 499 is P-type doped, and the first doped layer 418 on the other side of the light absorption layer 499 is N-type doped.

[0128] In this embodiment, the photoelectric detection structure is located above the side of the optical waveguide layer.

[0129] Specifically, the photodetector structure is located above the side of the optical waveguide layer, and the extension direction of the photodetector structure and the optical waveguide layer is located in the optical signal transmission direction, so that the optical waveguide layer can guide the incident light signal to the photodetector structure in the photoelectric conversion region 400A, and the photodetector structure can convert the input light signal into an electrical signal.

[0130] In this embodiment, the semiconductor structure further includes a fourth dielectric layer, located on top of the substrate 402 and covering the photodetector.

[0131] Specifically, the fourth dielectric layer provides a technological basis for setting the confining light field layer 478, enabling the confining light field layer 478 in the fourth dielectric layer to confine the incident light to the region above the light absorption layer 499. Correspondingly, while further reducing the size of the light absorption layer 499, the probability of light scattering loss of the incident light can also be reduced.

[0132] In this embodiment, the light field confining layer 478 is located in the fourth dielectric layer above the first doped layer 418. In other embodiments, the light field confining layer is located above the fourth dielectric layer above the first doped layer.

[0133] Specifically, the shape of the confining light field layer 478 includes one or more of the following: rectangular, trapezoidal, elliptical, and triangular. The rectangular, trapezoidal, elliptical, and triangular confining light field layers 478 are formed on top of the first doped layer 418. The opposing confining light field layers 478 can form a slit for incident light above the light absorption layer 499, confining the incident light to the region above the light absorption layer 499, so that the light absorption layer 499 can fully absorb the incident light signal.

[0134] As an example, the shape of the light field layer 478 is restricted to a trapezoid.

[0135] In this embodiment, the material of the light field confinement layer 478 includes noble metals.

[0136] Specifically, noble metals have a high density of free electrons, which can effectively support the excitation and propagation of surface plasmas.

[0137] In this embodiment, the material of the light field confinement layer 478 includes one or both of copper and gold.

[0138] Specifically, the surface plasmon resonance characteristics of copper and gold exhibit significant light field enhancement and localization effects within a specific wavelength range. Surface plasmon polaritons propagate along the interface between the metal and the medium, and their electric field decays exponentially in both the metal and the medium. This characteristic enables SPP to confine light energy within a nanoscale region, breaking through the diffraction limit of traditional optics. Copper and gold can overcome the optical diffraction limit, thereby confining the incident light to the region above the light absorption layer 499, reducing the probability of light scattering loss, and thus enabling the light absorption layer 499 to fully absorb the incident light signal, improving the quantum efficiency of the photoelectric detection structure.

[0139] It should be noted that the thickness of the light-restricting layer 478 should not be too large or too small. If the thickness of the light-restricting layer 478 is too large, it can easily lead to a weakening of the near-field intensity of surface plasmon polaritons and a reduction in coupling efficiency; if the thickness of the light-restricting layer 478 is too small, it will be difficult for the light-restricting layer 478 to confine the incident light to the region above the light-absorbing layer 499, thereby increasing the probability of light scattering loss of the incident light. Therefore, in this embodiment, the thickness of the light-restricting layer 478 is between 50 micrometers and 300 micrometers.

[0140] It should also be noted that, taking the direction of extension of the light-restricting layer 478, which is parallel to the surface of the substrate and perpendicular to the extension direction of the light-restricting layer 478, as the lateral direction, the lateral dimension of the light-restricting layer 478 should not be too large or too small. If the lateral dimension of the light-restricting layer 478 is too large, it compresses the process window for subsequently forming interconnect vias electrically connected to the first doped layer, increasing the difficulty of forming interconnect vias; if the lateral dimension of the light-restricting layer 478 is too small, it makes it difficult for the light-restricting layer 478 to confine the incident light to the region above the light-absorbing layer 499, correspondingly increasing the probability of light scattering loss of the incident light. Therefore, in this embodiment, taking the direction of extension of the light-restricting layer 478, which is parallel to the surface of the substrate and perpendicular to the extension direction of the light-restricting layer 478, as the lateral direction, the lateral dimension of the light-restricting layer 478 is 100 micrometers to 500 micrometers.

[0141] In this embodiment, the light field confinement layer 478 is also formed on top of the optical waveguide layer.

[0142] It should be noted that setting a confining optical field layer 478 on top of the optical waveguide layer can improve the coupling efficiency from the optical waveguide region 400B to the photoelectric conversion region 400A. This is because the confining optical field layer 478 can enhance the interaction between the incident light and the light absorption layer 499. By utilizing the subwavelength confining capability of surface plasmon polaritons (SPP), the interaction between the incident light and the light absorption layer 499 can be enhanced, thereby improving the light absorption efficiency and overall performance, and thus improving the coupling efficiency from the optical waveguide region 400B to the photoelectric conversion region 400A.

[0143] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for forming a semiconductor structure, characterized in that, include: A substrate is provided, the substrate including a photoelectric conversion region; A photodetector structure is formed on top of the substrate of the photoelectric conversion region. The photodetector structure includes a light absorption layer and a first doped layer that contacts both sides of the light absorption layer. The first doped layers on both sides of the light absorption layer have different doping types. A confining light field layer is formed on top of the first doped layer on both sides of the light absorption layer, and the extension direction of the confining light field layer is the same as the extension direction of the first doped layer.

2. The method for forming a semiconductor structure as described in claim 1, characterized in that, The step of forming the confining light field layer includes: forming a fourth dielectric layer covering the photodetector structure on top of the substrate; forming a third groove in the fourth dielectric layer on top of the first doped layer; and forming the confining light field layer in the third groove.

3. The method for forming a semiconductor structure as described in claim 2, characterized in that, The step of forming a confined light field layer in the third groove includes: forming a confined light field material layer on top of the fourth dielectric layer and in the third groove; taking the top of the fourth dielectric layer as the stop position, performing planarization on the confined light field material layer above the top of the fourth dielectric layer, and using the remaining confined light field material layer located in the third groove as the confined light field layer.

4. The method for forming a semiconductor structure as described in claim 1, characterized in that, The step of forming the confined light field layer includes: forming a fourth dielectric layer covering the photodetector structure on top of the substrate; forming a second mask layer having a first mask opening on top of the fourth dielectric layer, the first mask opening being located above the first doped layer; and forming the confined light field layer in the first mask opening.

5. The method for forming a semiconductor structure as described in claim 4, characterized in that, The step of forming a confined light field layer in the first mask opening includes: forming a confined light field material layer on top of the second mask layer and in the first mask opening; removing the second mask layer and the confined light field material layer on top of the fourth dielectric layer, and using the remaining confined light field material layer located above the first doped layer as the confined light field layer.

6. The method for forming a semiconductor structure as described in claim 5, characterized in that, The process for removing the second mask layer and the light field limiting material layer on top of the fourth dielectric layer includes an adhesive stripping process.

7. The method for forming a semiconductor structure as described in claim 1, characterized in that, The shape of the confined light field layer includes one or more of the following: rectangular, trapezoidal, elliptical, and triangular.

8. The method for forming a semiconductor structure as described in claim 1, characterized in that, The thickness of the confined light field layer is between 50 micrometers and 300 micrometers; The lateral dimension of the light field confinement layer is 100 micrometers to 500 micrometers, with the lateral direction being parallel to the surface of the substrate and perpendicular to the extension direction of the light field confinement layer.

9. The method for forming a semiconductor structure as described in claim 1, characterized in that, The material of the light field confinement layer includes precious metals.

10. The method for forming a semiconductor structure as described in claim 1 or 9, characterized in that, The material of the light field confinement layer includes one or both of copper and gold.

11. The method for forming a semiconductor structure as described in claim 1, characterized in that, In the step of providing a substrate, the substrate includes a bottom insulating layer and a substrate located on top of the bottom insulating layer, and the bottom insulating layer exposes the top surface of the substrate; The steps for forming the photodetector structure include: forming a first dielectric layer on top of the substrate; forming a light-absorbing material layer in the first dielectric layer on top of the substrate, with the first dielectric layer exposing the top surface of the light-absorbing material layer; patterning the ends of the light-absorbing material layer to form a plurality of openings surrounded by the sidewalls of the first dielectric layer, the top surface of the substrate, and the remaining sidewalls of the light-absorbing material layer, with the remaining light-absorbing material layer serving as the light-absorbing layer; forming a first doped layer in contact with the light-absorbing layer in the openings, wherein the light-absorbing layer and the first doped layers in contact with both sides of the light-absorbing layer constitute the photodetector structure; or, The steps for forming the photodetector structure include: performing ion implantation on the substrate to form adjacent first doped layers in the substrate, with the top surface of the first doped layers exposed; removing a portion of the substrate thickness between the adjacent first doped layers; and forming a light absorption layer on top of the remaining substrate, wherein the light absorption layer and the first doped layers constitute the photodetector structure.

12. The method for forming a semiconductor structure as described in claim 11, characterized in that, The step of forming a light-absorbing material layer in a first dielectric layer on top of the substrate includes: forming a first groove in the first dielectric layer on top of the substrate, the first groove exposing a portion of the top surface of the substrate; forming a light-absorbing material layer on top of the first dielectric layer and in the first groove; and planarizing the light-absorbing material layer above the top of the first dielectric layer.

13. The method for forming a semiconductor structure as described in claim 11, characterized in that, The step of removing a portion of the substrate thickness between adjacent first doped layers includes: forming a second dielectric layer on top of the substrate and on top of the first doped layer; removing the second dielectric layer above the substrate between adjacent first doped layers to expose a second groove on the top surface of the substrate; and removing a portion of the substrate thickness along the second groove using the remaining second dielectric layer as a mask.

14. The method for forming a semiconductor structure as described in claim 13, characterized in that, The step of forming a light-absorbing layer on top of the remaining substrate includes: forming a light-absorbing material layer on top of the second dielectric layer and in the second groove; using the top of the second dielectric layer as a stop position, planarizing the light-absorbing material layer above the top of the second dielectric layer, and using the remaining light-absorbing material layer located in the second groove as the light-absorbing layer.

15. The method for forming a semiconductor structure as described in claim 11, characterized in that, After forming adjacent first doped layers in the substrate, and before forming the light-absorbing layer, the formation method further includes: forming a first contact layer of the same doping type in the first doped layer, wherein the first doped layer exposes the top surface of the first contact layer.

16. The method for forming a semiconductor structure as described in claim 15, characterized in that, The process of forming a first contact layer with the same doping type in the first doped layer includes ion implantation.

17. The method for forming a semiconductor structure as described in claim 1, characterized in that, In the step of providing the substrate, the substrate further includes an optical waveguide region, and an optical waveguide layer is further formed in the substrate of the optical waveguide region; In the step of forming the photodetector structure, the photodetector structure is located above the side of the optical waveguide layer, and the extension direction of the photodetector structure and the optical waveguide layer is located in the optical signal transmission direction. In the step of forming the confined light field layer, the confined light field layer is also formed on top of the optical waveguide layer.

18. A semiconductor structure, characterized in that, include: A substrate, the substrate including a photoelectric conversion region; A photoelectric detection structure is located on top of the substrate of the photoelectric conversion region. The photoelectric detection structure includes a light absorption layer and a first doped layer that contacts both sides of the light absorption layer. The first doped layers on both sides of the light absorption layer have different doping types. A light field confinement layer is located on top of the first doped layer on both sides of the light absorption layer, and the extension direction of the light field confinement layer is the same as the extension direction of the first doped layer.

19. The semiconductor structure as claimed in claim 18, characterized in that, The semiconductor structure further includes: a fourth dielectric layer, located on top of the substrate and covering the photodetector; The light field confinement layer is located in the fourth dielectric layer on top of the first doped layer.

20. The semiconductor structure as claimed in claim 18, characterized in that, The semiconductor structure further includes: a fourth dielectric layer, located on top of the substrate and covering the photodetector; The light field confinement layer is located above the fourth dielectric layer on top of the first doped layer.

21. The semiconductor structure as claimed in claim 18, characterized in that, The shape of the confined light field layer includes one or more of the following: rectangular, trapezoidal, elliptical, and triangular.

22. The semiconductor structure as described in claim 18, characterized in that, The thickness of the confined light field layer is between 50 micrometers and 300 micrometers; The lateral dimension of the light field confinement layer is 100 micrometers to 500 micrometers, with the lateral direction being parallel to the surface of the substrate and perpendicular to the extension direction of the light field confinement layer.

23. The semiconductor structure as described in claim 18, characterized in that, The material of the light field confinement layer includes precious metals.

24. The semiconductor structure as described in claim 18 or 23, characterized in that, The material of the light field confinement layer includes one or both of copper and gold.

25. The semiconductor structure as claimed in claim 18, characterized in that, The substrate also includes an optical waveguide region; The semiconductor structure further includes: an optical waveguide layer located in the substrate of the optical waveguide region, and the photodetector structure and the extension direction of the optical waveguide layer are located in the optical signal transmission direction; The photoelectric detection structure is located on the side and above the optical waveguide layer; The confined light field layer is also formed on top of the optical waveguide layer.

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