Photoelectric detector and electronic equipment

Abstract

The invention discloses a photoelectric detector and electronic equipment, the photoelectric detector comprises a substrate, a light reflection structure, a micropore diaphragm, a heightening layer, a lens structure and a deep groove isolation structure arranged around the substrate, the micropore diaphragm is provided with a light hole, the micropore diaphragm is located at a first side of a first surface of the substrate in a depth direction, and the light hole is located at a second side of the first surface of the substrate. The first surface is a surface for absorbing light into the substrate, and the first side is a side opposite to the interior of the substrate; the heightening layer and the lens structure are located on the first side of the micropore diaphragm in the depth direction. The heightening layer is located between the lens structure and the micropore diaphragm in the depth direction. The reflective structure is located on the first side of the second surface of the substrate, and the second surface is a surface opposite to the first surface in the depth direction. And the light absorption efficiency of the photoelectric detector can be improved.

Description

Technical Field

[0001] This application relates to the semiconductor field, and more particularly to photodetectors and electronic devices. Background Technology

[0002] A photodetector is a device that converts light signals into electrical signals. The working principle of a photodetector is based on the photoelectric effect: when photons (particles of light) strike the detector's sensitive material, they excite electrons, which are then collected and converted into electrical signals.

[0003] The light absorption efficiency of a photodetector is the percentage of incident photon energy that is effectively absorbed and converted into electron-hole pairs. It is an important indicator of the photodetector's ability to convert light energy into electrical energy and determines the photodetector's response to light signals. The light absorption efficiency of a photodetector affects its performance in photoelectric response, such as quantum efficiency (QE) and photon detection efficiency (PDE). How to improve the light absorption efficiency of a photodetector has become an urgent technical problem to be solved. Summary of the Invention

[0004] This application provides a photodetector and electronic equipment to improve the light absorption efficiency of the photodetector.

[0005] In a first aspect, this application provides a photodetector, including a substrate, a reflective structure, a microaperture, a pad layer, a lens structure, and a deep trench isolation (DTI) structure disposed around the substrate, wherein: The micro-aperture has a light-transmitting hole, and the micro-aperture is located on a first side of a first surface of the substrate in the depth direction. The first surface is the surface that absorbs light into the interior of the substrate, and the first side is the side facing away from the interior of the substrate. The padding layer and the lens structure are located on the first side of the microaperture in the depth direction; The padding layer is located between the lens structure and the microaperture in the depth direction; The reflective structure is located on the first side of the second surface of the substrate, and the second surface is the surface opposite to the first surface in the depth direction.

[0006] In this technical solution, the photodetector includes a substrate, a reflective structure, a microaperture, a pad layer, a lens structure, and a DTI structure surrounding the substrate. The microaperture has a light-transmitting aperture and is located on a first side of a first surface of the substrate in the depth direction. The first surface is the surface that absorbs light into the substrate, and the first side is the side facing away from the substrate interior. The pad layer and the lens structure are located on the first side of the microaperture in the depth direction, and the pad layer is located between the lens structure and the microaperture in the depth direction. The lens structure and the pad layer work together to focus the incident light to a reasonable position, so that it can enter the substrate interior through the light-transmitting aperture of the microaperture. The reflective structure is located on a first side of a second surface of the substrate, and the second surface is the surface opposite to the first surface in the depth direction. The reflective structure, the DTI structure, and the microaperture form multiple light-reflecting surfaces, reflecting the light multiple times, extending the optical path of the light in the substrate, thereby increasing the light absorption efficiency of the photodetector. In addition, due to the presence of the microaperture, light entering the substrate interior is prevented from diverging to the outside of the substrate and forming optical crosstalk, thus improving the signal-to-noise ratio degradation caused by optical crosstalk.

[0007] In conjunction with the first aspect, in one possible design, the diameter of the light-transmitting aperture is set based on the size of the photodetector.

[0008] The diameter of the light-transmitting aperture is set according to the size of the photodetector, which can prevent the incident light from escaping after being focused into the substrate, thereby enhancing the light absorption efficiency of the photodetector.

[0009] In conjunction with the first aspect, in one possible design, the radius of curvature of the lens structure and the thickness of the padding layer are set based on the diameter of the light-transmitting hole.

[0010] The radius of curvature of the lens structure and the thickness of the pad layer are set based on the diameter of the light-transmitting hole, which can concentrate as much light as possible into the substrate through the light-transmitting hole, thereby enhancing the light absorption efficiency of the photodetector.

[0011] In conjunction with the first aspect, in one possible design, the material of the micro-aperture is a first metallic material, and the reflectivity of the first metallic material is greater than a preset reflectivity.

[0012] Using a highly reflective metallic material for the microaperture helps enhance its light reflectivity, thereby facilitating the full reflection of light from the substrate.

[0013] In conjunction with the first aspect, in one possible design, the photodetector further includes a light-scattering structure; the light-scattering structure is located at a first surface position of the substrate, the first surface position being the position corresponding to the light-transmitting hole on a second side of the first surface of the substrate, the second side being the side facing the interior of the substrate.

[0014] A light-diffusing structure is set at the position corresponding to the light-transmitting hole on the substrate. The light-diffusing structure can diffuse the incident light entering the substrate through the light-transmitting hole, thereby further extending the optical path in the substrate and increasing the light absorption efficiency of the photodetector.

[0015] In conjunction with the first aspect, in one possible design, the astigmatic structure is filled with a preset medium material, the preset medium material having a refractive index lower than a preset refractive index. Filling the diffused light structure with a low-refractive-index dielectric material can fully diffuse the light entering the substrate through the light-transmitting hole, thereby enhancing the optical path of the light within the substrate.

[0016] In conjunction with the first aspect, in one possible design, the astigmatic structure includes one or more inverted pyramidal structures, and / or one or more shallow trench structures.

[0017] Multiple inverted pyramidal structures or multiple shallow trench structures, with sloping surfaces forming multi-angle interfaces with incident light, enhance diffuse reflection, thereby extending the propagation path of light within the substrate.

[0018] In conjunction with the first aspect, in one possible design, the deep trench isolation structure is filled with at least two materials; the at least two materials include an insulating dielectric material and a second metallic material; the second metallic material separates the insulating dielectric material into inner and outer layers in the deep trench isolation structure, the inner layer of the insulating dielectric material surrounding the substrate, and the outer layer of the insulating dielectric material surrounding the second metallic material.

[0019] The DTI structure is filled with insulating and metallic materials. The inner insulating material can reflect light from the substrate, enhancing the optical path of light within the substrate. The outer insulating material provides electrical isolation, reducing electrical crosstalk between adjacent photodetectors. The metallic material in the middle isolates light, thereby reducing optical crosstalk between adjacent photodetectors.

[0020] In conjunction with the first aspect, in one possible design, the metal material forming the micro-aperture is connected to the second metal material within the deep trench isolation structure to form a metal-enclosed structure.

[0021] The metal material forming the microaperture is connected to the metal material within the DTI structure to form a metal-enclosed structure, which reduces the probability of light propagating to neighboring units and further suppresses optical crosstalk between adjacent photodetectors.

[0022] In conjunction with the first aspect, in one possible design, the photodetector further includes a pre-metal dielectric (PMD) layer and a wiring layer, wherein: the pre-metal dielectric layer and the wiring layer are located on a first side of the second surface of the substrate; the pre-metal dielectric layer is located between the substrate and the wiring layer in the depth direction.

[0023] Placing a metal front dielectric layer between the substrate and the wiring layer can form an electrically insulating layer, preventing electrode short circuits and crosstalk.

[0024] In conjunction with the first aspect, in one possible design, the wiring layer is a metal wiring layer, and the reflective structure is formed by reusing the metal wiring layer.

[0025] By reusing the metal wiring layer to form a reflective structure, materials can be saved.

[0026] In conjunction with the first aspect, in one possible design, the material of the metal front dielectric layer is an insulating dielectric material.

[0027] In a second aspect, a photodetector array is provided, comprising a plurality of photodetectors as described in the first aspect, arranged in an array.

[0028] Thirdly, an electronic device is provided, including an electronic component having a photodetector as described in the first aspect above.

[0029] This application can achieve the following technical effects: the lens structure, in conjunction with the padding layer, can focus the incident light to a reasonable position, thereby allowing it to enter the substrate through the light-transmitting aperture of the micro-aperture; the reflective structure is located on the first side of the second surface of the substrate, the second surface being the surface opposite to the first surface in the depth direction, and the reflective structure, the DTI structure, and the micro-aperture form multiple light-reflecting surfaces, reflecting the light multiple times, extending the optical path of the light within the substrate, thereby increasing the light absorption efficiency of the photodetector; in addition, due to the presence of the micro-aperture, light entering the substrate is prevented from scattering outside the substrate and forming optical crosstalk, thus improving the signal-to-noise ratio degradation caused by optical crosstalk. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram showing the relationship between the absorption coefficient / absorption depth of monocrystalline silicon material and wavelength. Figures 2-4 This is a schematic diagram of the structure of a photodetector provided in an embodiment of this application; Figure 5 A schematic diagram of the propagation path of light within the substrate of a photodetector, provided in an embodiment of this application; Figures 6-9 This is a schematic diagram of another photodetector provided in an embodiment of this application; Figure 10 A schematic diagram of the propagation path of light within the substrate of a photodetector, provided in an embodiment of this application; Figure 11 This is a schematic diagram of the structure of another photodetector provided in an embodiment of this application; Figure 12 This is a schematic diagram of a photodetector array provided in an embodiment of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0033] This application relates to the field of photoelectric detection. In photoelectric detection, when a semiconductor material is irradiated with light, if the energy of the photon exceeds the bandgap of the semiconductor, the semiconductor will absorb the photon and generate electron-hole pairs. Generally, the light absorption capacity of a semiconductor material decreases with increasing wavelength, and the "absorption coefficient" is commonly used as an indicator of the semiconductor material's light absorption capacity. Corresponding to the "absorption coefficient" is another indicator called "absorption depth," which represents the depth / thickness of the semiconductor material required to absorb approximately 63% of the incident light. Single-crystal silicon, as a commonly used substrate material for photodetectors, exhibits the following relationship between its absorption coefficient / absorption depth and wavelength: Figure 1 As shown. Taking green light with a wavelength of 550nm and near-infrared light with a wavelength of 940nm as examples: the absorption coefficient of green light with a wavelength of 550nm is 6400 cm⁻¹. -1 The corresponding absorption depth is 1.56 micrometers (µm), meaning that a single-crystal silicon material with a thickness of 1.56 µm can absorb 63% of the light at 550 nm. For near-infrared light with a wavelength of 940 nm, its absorption coefficient is 183 cm⁻¹. -1 The corresponding absorption depth is 54.6 μm, meaning that a silicon thickness of 54.6 μm is required to absorb 63% of the 940 nm light. This demonstrates that the absorption coefficient / absorption depth of a semiconductor material is negatively correlated with the wavelength of the light irradiating the semiconductor material.

[0034] In some feasible solutions, increasing the thickness of the substrate (such as silicon) can improve the light absorption efficiency of the substrate. However, increasing the thickness of the substrate means increased material costs and process difficulty, so it is necessary to find other solutions to improve the light absorption efficiency of the substrate.

[0035] The technical solution of this application improves the structure of the photodetector, thereby enhancing the optical path length of incident light within the silicon material and increasing light absorption efficiency. The photodetectors used in this application include, but are not limited to, PIN photodiodes, avalanche photodiodes (APDs), and single-photon avalanche diodes (SPADs).

[0036] The technical solution of this application is described in detail below.

[0037] First see Figures 2-4 , Figures 2-4 This is a schematic diagram of the structure of a photodetector provided in an embodiment of this application. Figure 2 The diagram shown is a vertical cross-sectional view of a photodetector provided in an embodiment of this application. Figure 3 The diagram shown is a cross-sectional view of the photodetector at the microaperture aperture. Figure 4 This diagram shows a cross-sectional view of the photodetector on the substrate. Figures 2-4 As shown, the photodetector 10 includes a substrate 101, a reflective structure 102, a microaperture 103, a pad layer 104, a lens structure 105, and a deep trench isolation structure 106 surrounding the substrate 101, wherein: The microaperture 103 is an optical element that modulates the energy distribution, spatial frequency, or propagation direction of light to limit the diameter, shape, or propagation path of the light beam.

[0038] The microaperture 103 has a light-transmitting aperture 1031. The microaperture 103 is located on a first side of a first surface of the substrate 101 in the depth direction. The first surface is the surface that absorbs light into the interior of the substrate 101. The first side is the side facing away from the interior of the substrate 101. The depth direction is the same as the incident direction of light and is perpendicular to the transverse cross-section of the photodetector 10.

[0039] The padding layer 104 and the lens structure 105 are located on the first side of the microaperture 103 in the depth direction.

[0040] The padding layer 104 is located between the lens structure 105 and the microaperture stop 103 in the depth direction. The padding layer 104 can be a transparent organic material, used to planarize the surface of the microaperture stop and adjust the focal point of the lens structure 105 to a reasonable position.

[0041] The lens structure 105 is used to converge incident light to the light-transmitting aperture 1031, through which it enters the substrate 101. The lens structure 105 may include microlenses. The microlenses may be spherical or cylindrical, and this application is not limited to either.

[0042] The substrate 101 serves as the physical carrier of the photodetector 10 and can act as a light-absorbing layer to absorb light and form electron-hole pairs. The materials of the substrate 101 include, but are not limited to, single-crystal silicon and indium phosphide.

[0043] A dielectric material with a refractive index lower than a preset refractive index can be filled between the substrate 101 and the microaperture 103 to form a low-refractive-index layer L1. The preset refractive index is the refractive index that defines whether the dielectric material is a low-refractive-index dielectric material. The preset refractive index is, for example, 1.5.

[0044] The reflective structure 102 is located on the first side of the second surface of the substrate 101, and the second surface is the surface opposite to the first surface in the depth direction.

[0045] The reflective structure 102 is used to reflect light within the substrate 101.

[0046] The deep trench isolation structure 106 surrounding the substrate 101 is used to isolate the photodetector 10 from other circuit elements, reduce capacitive and resistive coupling between the photodetector 10 and other circuit elements, thereby reducing noise and improving response speed.

[0047] Irradiated Figure 2 The propagation path of incident light on the surface of the photodetector 10 and within the photodetector 10 can be found in [reference]. Figure 5 In the example, incident light is converged by a lens structure to form ray a1, which enters the substrate through a light-transmitting aperture. Ray a1 is reflected when it reaches the deep trench isolation structure on one side, and the propagation direction of the reflected ray is shown in ray a2. Ray a2 is reflected when it reaches the reflective structure, and the propagation direction of the reflected ray is shown in ray a3. Ray a3 is reflected when it reaches the interface between the low-refractive layer and the micro-aperture, and the propagation direction of the reflected ray is shown in ray a4. Ray a4 is reflected when it reaches the deep trench isolation structure on the other side, and the propagation direction of the reflected ray is shown in ray a5. Ray a5 continues to propagate, undergoing more reflection, refraction, or diffraction processes, which increases the optical path length of the ray within the substrate.

[0048] Combination Figure 2 and Figure 5As can be seen, the photodetector includes a substrate, a reflective structure, a microaperture, a pad layer, a lens structure, and a DTI structure surrounding the substrate. The microaperture has a light-transmitting aperture and is located on the first side of the first surface of the substrate in the depth direction. The first surface is the surface that absorbs light into the substrate, and the first side is the side facing away from the substrate interior. The pad layer and the lens structure are located on the first side of the microaperture in the depth direction, and the pad layer is located between the lens structure and the microaperture in the depth direction. The lens structure and the pad layer work together to focus the incident light to a reasonable position, so that it can enter the substrate interior through the light-transmitting aperture of the microaperture. The reflective structure is located on the first side of the second surface of the substrate, and the second surface is the surface opposite to the first surface in the depth direction. The reflective structure, the DTI structure, and the microaperture form multiple light-reflecting surfaces, reflecting the light multiple times, extending the optical path of the light in the substrate, thereby increasing the light absorption efficiency of the photodetector. In addition, due to the presence of the microaperture, light entering the substrate interior is prevented from diverging to the outside of the substrate and forming optical crosstalk, thus improving the signal-to-noise ratio degradation caused by optical crosstalk.

[0049] In some possible designs, the diameter of the aforementioned aperture 1031 is set based on the size of the photodetector 10. The diameter of the aperture 1031 allows light focused by the lens structure 105 to enter the substrate 101 and prevents light entering the substrate 101 from escaping. The diameter of the aperture 1031 is positively correlated with the size of the photodetector 10; that is, the larger the cross-sectional area of ​​the photodetector 10, the larger the aperture 1031. For example, if the cross-sectional area of ​​the photodetector 10 is 10 micrometers, the diameter of the aperture 1031 can be 3 micrometers.

[0050] The diameter of the light-transmitting aperture is set according to the size of the photodetector, which can prevent the incident light from escaping after being focused into the substrate, thereby enhancing the light absorption efficiency of the photodetector.

[0051] In some possible designs, the radius of curvature of the lens structure 105 and the thickness of the padding layer 104 are set based on the diameter of the light-transmitting aperture 1031. The radius of curvature of the lens structure 105 and the thickness of the padding layer 104 ensure that more than a predetermined percentage (e.g., 90%) of the incident light can enter the substrate 101 through the light-transmitting aperture 1031.

[0052] The radius of curvature of the lens structure and the thickness of the pad layer are set based on the diameter of the light-transmitting hole, which can concentrate as much light as possible into the substrate through the light-transmitting hole, thereby enhancing the light absorption efficiency of the photodetector.

[0053] In some possible designs, the material of the aforementioned microaperture 103 is a first metallic material, and the reflectivity of the first metallic material is greater than a preset reflectivity. The preset reflectivity is the reflectivity that defines whether the metallic material is a high-reflectivity metallic material, and the preset reflectivity can be set based on specific optical reflection requirements. For example, a photodetector is mainly used to detect incident light in the infrared or near-infrared bands, and the preset reflectivity can be 80%. The first metallic material includes, but is not limited to, metallic materials such as aluminum, copper, and platinum.

[0054] Using a highly reflective metallic material for the microaperture helps enhance its light reflectivity, thereby facilitating the full reflection of light from the substrate.

[0055] In some possible designs, such as Figure 2 and 4 As shown, the deep trench isolation structure 106 described above is filled with at least two materials. The at least two materials filling the deep trench isolation structure 106 include an insulating dielectric material and a second metal material. The second metal material separates the insulating dielectric material into inner and outer layers within the deep trench isolation structure 106. The inner layer of the insulating dielectric material surrounds the substrate 101, and the outer layer surrounds the second metal material. The insulating dielectric material filling the deep trench isolation structure 106 is used for electrical isolation, and this insulating dielectric material includes, but is not limited to, insulating materials such as silicon oxide, aluminum oxide, hafnium oxide, or tantalum oxide. The second metal material filling the deep trench isolation structure 106 is used for optical isolation, and this second metal material includes, but is not limited to, metals such as tungsten and copper.

[0056] The DTI structure is filled with insulating and metallic materials. The inner insulating material can reflect light from the substrate, enhancing the optical path of light within the substrate. The outer insulating material provides electrical isolation, reducing electrical crosstalk between adjacent photodetectors. The metallic material in the middle isolates light, reducing optical crosstalk between adjacent photodetectors.

[0057] Please see next. Figures 6-9 , Figures 6-9 This is a schematic diagram of another photodetector provided in an embodiment of this application. Figure 6 and Figure 8 The diagram shown is a vertical cross-sectional view of another photodetector provided in an embodiment of this application. Figure 7 and Figure 9 The diagram shown is a cross-sectional view of another photodetector provided in this application embodiment at the substrate.

[0058] like Figures 6-9As shown, the photodetector 20 includes a substrate 201, a reflective structure 202, a microaperture 203, a pad layer 204, a lens structure 205, a deep trench isolation structure 206 surrounding the substrate 201, and a light-scattering structure 207, wherein: For details regarding the substrate 201, reflective structure 202, micro-aperture stop 203, pad layer 204, lens structure 205, and deep trench isolation structure 206 surrounding the substrate 201, please refer to the foregoing descriptions of the substrate 101, reflective structure 102, micro-aperture stop 103, pad layer 104, lens structure 105, and deep trench isolation structure 106 surrounding the substrate 101; these details will not be repeated here.

[0059] The light-diffusing structure 207 is located on the first surface of the substrate 201. The first surface is the position corresponding to the second side of the first surface of the substrate 201 and the light-transmitting hole 2031. The second side is the side facing the interior of the substrate 201.

[0060] The light-diffusing structure 207 is used to diffuse the light entering the substrate 201 through the light-transmitting hole 2031, so that the light can propagate to various areas of the substrate 201.

[0061] Irradiated Figures 6-9 The propagation path of incident light on the surface of the photodetector 20 and within the photodetector 20 can be found in [reference]. Figure 10 For example, incident light is converged by a lens structure to form ray b1. Ray b1 enters the substrate through a light-transmitting aperture. Upon passing through a diffusing structure, refraction and diffraction occur, causing ray b1 to deflect. The deflected ray's propagation direction is shown in ray b2. Ray b2 is reflected when it reaches a deep trench isolation structure on one side. The reflected ray's propagation direction is shown in ray b3. Ray b3 is reflected when it reaches a reflective structure. The reflected ray's propagation direction is shown in ray b4. Ray b4 is reflected when it reaches a deep trench isolation structure on the other side. The reflected ray's propagation direction is shown in ray b5. Ray b5 is reflected when it reaches a micro-aperture stop. The reflected ray's propagation direction is shown in ray b6. Ray b6 continues to propagate, undergoing further reflection, refraction, and diffraction, increasing the optical path length within the substrate.

[0062] Combination Figures 6-10 It can be seen that by setting a light-diffusing structure at the position corresponding to the light-transmitting hole on the substrate, the light-diffusing structure can diffuse the incident light entering the substrate through the light-transmitting hole, thereby further extending the optical path in the substrate and increasing the light absorption efficiency of the photodetector.

[0063] In some possible designs, the aforementioned astigmatic structure 207 is filled with a preset dielectric material, the refractive index of which is lower than a preset refractive index. The preset dielectric material includes, but is not limited to, silicon oxide, titanium oxide, and silicon dioxide.

[0064] Filling the diffused light structure with a low-refractive-index dielectric material can fully diffuse the light entering the substrate through the light-transmitting hole, thereby enhancing the optical path of the light within the substrate.

[0065] In some possible designs, such as Figure 6 and Figure 7 As shown, the astigmatism structure 207 includes one or more inverted pyramid-shaped structures. An inverted pyramid-shaped structure refers to a three-dimensional structure resembling a cone or pyramid. The cross-sectional area of ​​the inverted pyramid-shaped structure varies with depth; the cross-sectional area of ​​the inverted pyramid-shaped structure near the first surface of the substrate 201 is larger than the cross-sectional area away from the first surface of the substrate 201, exhibiting a shape that is wider at the top and narrower at the bottom. Multiple inverted pyramid-shaped structures can be distributed in an array or randomly arranged at the first surface of the substrate 201.

[0066] The inclined surface of the inverted pyramid structure forms a multi-angle interface. Light entering the substrate 201 through the light-transmitting hole 2031 is reflected by the multi-angle interface of the inverted pyramid structure, which prolongs the propagation path of the light in the substrate.

[0067] In some possible designs, such as Figure 8 and Figure 9 As shown, the light-scattering structure 207 includes one or more shallow trench structures. The shallow trench structure is formed by etching trenches of a certain depth and width at the first surface of the substrate and then filling them with insulating material. The cross-section of the shallow trench structure is rectangular or nearly rectangular, with vertical or slightly inclined edges. Multiple shallow trench structures can be arranged in parallel or periodically at the first surface of the substrate 201.

[0068] The shallow trench structure can increase the surface roughness of the first surface of the substrate. Light entering the substrate 201 through the light-transmitting hole 2031 is scattered at the first surface, thereby extending the propagation path of the light in the substrate.

[0069] It is understood that the astigmatic structure 207 is not limited to the inverted pyramid structure or shallow groove structure mentioned above, but may also include other structures, such as microlens arrays, porous film structures, etc., and this application does not impose any restrictions on them.

[0070] Please see next. Figure 11 , Figure 11 This is a schematic diagram of the structure of another photodetector provided in an embodiment of this application. Figure 11This diagram illustrates a vertical cross-sectional structure of another photodetector provided in an embodiment of this application. Figure 11 As shown, the photodetector 30 includes a substrate 301, a reflective structure 302, a microaperture 303, a pad layer 304, a lens structure 305, a deep trench isolation structure 306 surrounding the substrate 301, and a light-scattering structure 307, wherein: For a description of the substrate 301, reflective structure 302, microaperture aperture 303, padding layer 304, lens structure 305, deep trench isolation structure 306 surrounding the substrate 301, and diffuser structure 307, please refer to the preceding description. Figures 2-9 The relevant descriptions will not be repeated here.

[0071] The metal material forming the micro-aperture 303 is connected to the second metal material within the deep trench isolation structure 306 to form a metal-sealed structure. The metal material forming the micro-aperture 303 and the second metal material are the same metal material; for example, both the metal material forming the micro-aperture 303 and the second metal material are copper.

[0072] The metal material forming the microaperture is connected to the metal material within the DTI structure to form a metal-enclosed structure, which reduces the probability of light propagating to neighboring units and further suppresses optical crosstalk.

[0073] In some possible designs, such as Figures 2-11 As shown, the photodetector also includes a metal front dielectric layer L2 and a wiring layer L3, which are located on the first side of the second surface of the substrate. The metal front dielectric layer L2 is located between the substrate and the wiring layer L3 in the depth direction. The metal front dielectric layer L2 acts as a bridge between the substrate and the wiring layer L3, used for surface planarization of the substrate, protecting the substrate from damage by subsequent processes, and avoiding interface defects. The material of the metal front dielectric layer L2 includes, but is not limited to, silicon dioxide and doped silicon dioxide. The wiring layer L3 is a material layer composed of alternately stacked wires, used to transmit the electrical signals generated by the photodetector. The material of the wiring layer L3 includes, but is not limited to, aluminum, copper, and tungsten.

[0074] Placing a metal front dielectric layer between the substrate and the wiring layer can form an electrically insulating layer, preventing electrode short circuits and crosstalk.

[0075] In some possible designs, the aforementioned wiring layer L3 is a metal wiring layer, and the aforementioned reflective structure is formed by reusing the metal wiring layer.

[0076] By reusing the metal wiring layer to form a reflective structure, materials can be saved.

[0077] In some possible designs, the material of the aforementioned metal front dielectric layer is an insulating dielectric material.

[0078] Understandably, the aforementioned photodetector may also include a main junction, which is located within the substrate of the photodetector near the second surface. The substrate absorbs photons, generating electron-hole pairs. Electrons migrate towards the high reverse-biased voltage region with the assistance of the electric field formed by the reverse bias voltage, reaching the main junction. Avalanche multiplication occurs in the main junction region, generating current pulses, thus forming an effective detection signal. The main junction can be an N-on-P structure or a P-on-N structure. Electrodes are also disposed in the metal front dielectric layer of the photodetector, connected to the metal wiring layer. The current pulses generated within the substrate flow through the electrodes in the metal front dielectric layer to the metal wiring layer, thereby realizing the transmission of electrical signals.

[0079] Please see again Figure 12 , Figure 12 This is a schematic diagram of the structure of the photodetector array provided in an embodiment of this application. Figure 12 The diagram shown is a vertical cross-sectional view of multiple photodetectors arranged adjacent to each other in a photodetector array provided in this application embodiment. Figure 12 As shown, the photodetector array 40 includes multiple photodetectors arranged in an array, and the photodetectors can be as described above. Figure 2 , Figure 6 , Figure 8 or Figure 11 As shown.

[0080] like Figure 12 As shown, two adjacent photodetectors in the photodetector array share a single deep trench isolation structure. For a detailed description of the deep trench isolation structure, please refer to the previous section. Figures 2-4 The description of the deep trench isolation structure 106 will not be repeated here.

[0081] The deep trench isolation structure is used to isolate two adjacent photodetectors. Specifically, the insulating dielectric material in the deep trench isolation structure is used to prevent electrons generated in the substrate of one photodetector from entering the substrate of the other photodetector, thereby achieving electrical isolation between the two adjacent photodetectors and reducing electrical crosstalk between them. The metallic material in the deep trench isolation structure is used to prevent light from entering the substrate of one photodetector from entering the substrate of the other photodetector, thereby achieving optical isolation between the two adjacent photodetectors and reducing optical crosstalk between them.

[0082] like Figure 12 As shown, the microapertures and low-refractive-index layers of two adjacent photodetectors in the photodetector array are connected. For a detailed description of the microapertures and low-refractive-index layers, please refer to the previous section. Figures 2-4The microaperture 103 and the low-refractive-index layer L1 are introduced below. Since the microaperture is made of a first metallic material and the low-refractive-index layer is made of a medium material with a refractive index lower than the preset refractive index, light entering the substrate of the photodetector will be reflected back into the substrate when it reaches the interface between the low-refractive-index layer and the microaperture. This prevents light from entering the substrate of one photodetector from the substrate of another, thereby achieving optical isolation between two adjacent photodetectors and reducing optical crosstalk between them.

[0083] like Figure 12 As shown, the metal front dielectric layers of two adjacent photodetectors in the photodetector array are connected. For a detailed description of the metal front dielectric layers, please refer to the previous section. Figures 2-11 The relevant descriptions will not be repeated here. Since the metal front dielectric layer forms an electrically insulating layer, it can prevent electrons generated in the substrate of one photodetector from entering the substrate of another photodetector, thereby reducing electrical crosstalk between two adjacent photodetectors.

[0084] The photodetector of this application can be used to manufacture electronic devices, such as image sensors, laser sensors, and other electronic devices.

[0085] This application also provides an electronic device, including an electronic device with a photodetector, the photodetector being as described above. Figures 2-11 As shown, please refer to the aforementioned... Figures 2-11 The relevant information will not be repeated here.

[0086] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0087] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A photodetector, characterized in that, It includes a substrate, a reflective structure, a micro-aperture aperture, a pad layer, a lens structure, and a deep trench isolation structure surrounding the substrate, wherein: The micro-aperture has a light-transmitting hole, and the micro-aperture is located on a first side of a first surface of the substrate in the depth direction. The first surface is the surface that absorbs light into the interior of the substrate, and the first side is the side facing away from the interior of the substrate. The padding layer and the lens structure are located on the first side of the microaperture in the depth direction; The padding layer is located between the lens structure and the microaperture in the depth direction; The reflective structure is located on the first side of the second surface of the substrate, and the second surface is the surface opposite to the first surface in the depth direction.

2. The photodetector according to claim 1, characterized in that, The diameter of the light-transmitting aperture is set based on the size of the photodetector.

3. The photodetector according to claim 1, characterized in that, The radius of curvature of the lens structure and the thickness of the padding layer are set based on the diameter of the light-transmitting hole.

4. The photodetector according to claim 1, characterized in that, The micro-aperture is made of a first metallic material, and the reflectivity of the first metallic material is greater than a preset reflectivity.

5. The photodetector according to any one of claims 1-4, characterized in that, The photodetector also includes a light-scattering structure; The light-scattering structure is located on the first surface of the substrate, which is the position of the second side of the first surface of the substrate corresponding to the light-transmitting hole, and the second side is the side facing the interior of the substrate.

6. The photodetector according to claim 5, characterized in that, The astigmatic structure is filled with a preset medium material, and the refractive index of the preset medium material is lower than the preset refractive index.

7. The photodetector according to claim 5, characterized in that, The astigmatic structure includes one or more inverted pyramidal structures, and / or one or more shallow groove structures.

8. The photodetector according to any one of claims 1-4, characterized in that, The deep trench isolation structure is filled with at least two materials; the at least two materials include an insulating dielectric material and a second metal material; the second metal material separates the insulating dielectric material into inner and outer layers in the deep trench isolation structure, the inner layer of the insulating dielectric material surrounds the substrate, and the outer layer of the insulating dielectric material surrounds the second metal material.

9. The photodetector according to claim 8, characterized in that, The metal material forming the micro-aperture is connected to the second metal material within the deep trench isolation structure to form a metal closed structure.

10. The photodetector according to any one of claims 1-4, characterized in that, The photodetector further includes a metal front dielectric layer and a wiring layer, wherein: The metal front dielectric layer and the wiring layer are located on the first side of the second surface of the substrate; The metal front dielectric layer is located between the substrate and the wiring layer in the depth direction.

11. The photodetector according to claim 10, characterized in that, The wiring layer is a metal wiring layer, and the reflective structure is formed by reusing the metal wiring layer.

12. The photodetector according to claim 10, characterized in that, The material of the metal front dielectric layer is an insulating dielectric material.

13. A photodetector array, characterized in that, It includes multiple photodetectors arranged in an array as described in any one of claims 1-12.

14. An electronic device, characterized in that, It includes electronic devices, said electronic devices having a photodetector as described in any one of claims 1-12.

Images