Photoelectric detector and electronic equipment

Abstract

The invention discloses a photoelectric detector and electronic equipment, the photoelectric detector comprises a substrate, a reflective structure, a multilayer film filter and a deep trench isolation structure arranged around the substrate, the multilayer film filter is a multilayer film structure formed by alternately stacking at least two film materials, the multilayer film filter is located on the first side of the first surface of the substrate in the depth direction, the first surface is the surface which absorbs light into the substrate, and the first side is the side back to the interior of the substrate; the multilayer film filter is used for light of a target detection wave band to pass through, and the target detection wave band is a detection wave band of the photoelectric detector; 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. According to the technical scheme, 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 multilayer filter, and a deep trench isolation (DTI) structure disposed around the substrate, wherein: The multilayer filter is a multilayer thin film structure formed by alternating stacking of at least two thin film materials. The multilayer filter 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 multilayer filter is used to allow light in the target detection band to pass through, and the target detection band is the detection band of the photodetector. 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 multilayer filter, and a deep trench isolation structure surrounding the substrate. The reflective structure is located on a first side of the second surface of the substrate. The second surface is the surface opposite to the first surface in the depth direction, and the first side is the side facing away from the interior of the substrate. The multilayer filter is a multilayer thin film structure formed by alternating stacking of at least two thin film materials. The multilayer filter is located on a first side of the first surface of the substrate in the depth direction. The multilayer filter is used to allow light of the target detection band to pass through, which is the detection band of the photodetector. The reflective structure reflects the light entering the substrate through the multilayer filter, extending the optical path of the light within the substrate, thereby increasing the light absorption efficiency of the photodetector.

[0007] In conjunction with the first aspect, in one possible design, the multilayer filter is integrated onto the substrate via a filter integration process.

[0008] By integrating multilayer filters directly onto a substrate using filter integration technology, the module structure can be simplified and manufacturing costs reduced.

[0009] In conjunction with the first aspect, in one possible design, the light of the target detection band is reflected at a first interface of the multilayer filter, the first interface being an interface close to the first surface, and the reflectivity of the light of the target detection band at the first interface is positively correlated with the incident angle of the light of the target detection band at the first interface.

[0010] The reflectivity of light at the interface of a multilayer filter is positively correlated with the incident angle of the light at the interface, which helps to fully reflect the light.

[0011] In conjunction with the first aspect, in one possible design, when the incident angle of the light in the target detection band at the first interface is greater than a preset angle, the reflectivity of the light in the target detection band at the first interface is greater than a preset reflectivity.

[0012] Multilayer film filters have high reflectivity for light incident at large angles, which helps to fully reflect the light.

[0013] In conjunction with the first aspect, in one possible design, the photodetector also includes a light-scattering structure; The light-scattering structure is located on the 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 provided on the inner side of the incident surface of the substrate. The light-diffusing structure can fully diffuse the incident light that enters the substrate through the multilayer film filter, 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 refractive index of which is lower than a preset refractive index.

[0016] By filling the scattering structure with a low-refractive-index dielectric material, light is prevented from propagating inside the scattering structure, allowing as much light as possible that can pass through the multilayer filter to enter the substrate.

[0017] In conjunction with the first aspect, in one possible design, the astigmatic structure includes multiple inverted pyramidal structures and / or multiple shallow groove structures.

[0018] 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.

[0019] 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 metallic material; the metallic material in the deep trench isolation structure separates the insulating dielectric material into inner and outer layers, the inner layer of the insulating dielectric material surrounding the substrate, and the outer layer of the insulating dielectric material surrounding the metallic material.

[0020] 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.

[0021] In conjunction with the first aspect, in one possible design, the photodetector further includes a metal grid structure, wherein: the metal grid structure is located in the depth direction between the deep trench isolation structure and the multilayer filter, and the cross-section of the metal grid structure covers the cross-section of the deep trench isolation structure.

[0022] By setting up a metal grid, the probability of light propagating to neighboring units can be reduced, further suppressing optical crosstalk between adjacent photodetectors.

[0023] In a first aspect of the design, the photodetector further includes a padding layer and a lens structure, wherein: the padding layer and the lens structure are located on a first side of the multilayer filter in the depth direction; and the padding layer is located between the lens structure and the multilayer filter in the depth direction.

[0024] Placing a pad layer and lens structure above the multilayer filter can enhance the light collection efficiency of the photodetector.

[0025] 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 second side of a second surface of the substrate; the pre-metal dielectric layer is located between the substrate and the wiring layer in the depth direction.

[0026] 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.

[0027] 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.

[0028] By reusing the metal wiring layer to form a reflective structure, materials can be saved.

[0029] In conjunction with the first aspect, in one possible design, the material of the metal front dielectric layer is an insulating dielectric material.

[0030] In a second aspect, a photodetector array is provided, comprising a plurality of photodetectors as described in the first aspect, arranged in an array.

[0031] Thirdly, an electronic device is provided, including an electronic component having a photodetector as described in the first aspect above.

[0032] This application can achieve the following technical effects: the multilayer film filter is used to pass light through the target detection band, which is the detection band of the photodetector; the reflective structure reflects the light entering the substrate through the multilayer film filter, extending the optical path within the substrate, thereby increasing the light absorption efficiency of the photodetector. Attached Figure Description

[0033] 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.

[0034] Figure 1 This is a schematic diagram showing the relationship between the absorption coefficient / absorption depth of monocrystalline silicon material and wavelength. Figures 2-3 This is a schematic diagram of the structure of a photodetector provided in an embodiment of this application; Figure 4 A schematic diagram showing the transmittance of infrared light by a multilayer film filter composed of alternating stacks of silicon dioxide and amorphous silicon is shown. Figure 5 A schematic diagram of the propagation path of light within the substrate of a photodetector, provided in an embodiment of this application; Figure 6 The curve showing the relationship between the incident angle and reflectivity for a multilayer filter composed of alternating layers of silicon dioxide and amorphous silicon; Figures 7-10 This is a schematic diagram of another photodetector provided in an embodiment of this application.

[0035] Figure 11 This is a schematic diagram of the propagation path of light within a photodetector, provided in an embodiment of this application. Figure 12 This is a schematic diagram of the structure of another photodetector provided in an embodiment of this application; Figure 13 This is a schematic diagram of the structure of another photodetector provided in an embodiment of this application; Figure 14 This is a schematic diagram of a photodetector array provided in an embodiment of this application. Detailed Implementation

[0036] 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.

[0037] 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. -1The 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.

[0038] 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.

[0039] The technical solution of this application improves the structure of the photodetector, thereby increasing the optical path length of the incident light within the substrate and achieving the goal of increasing light absorption efficiency. The photodetectors of this application include, but are not limited to, PIN photodiodes, avalanche photodiodes (APDs), and single-photon avalanche diodes (SPADs).

[0040] The technical solution of this application is described in detail below.

[0041] First see Figures 2-3 , Figures 2-3 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 This diagram shows a cross-sectional view of the photodetector on the substrate. Figure 2 and Figure 3 As shown, the photodetector 10 includes a substrate 101, a reflective structure 102, a multilayer filter 103, and a deep trench isolation structure 104 surrounding the substrate 101, wherein: The multilayer filter 103 is a multilayer thin film structure formed by alternating stacking of at least two thin film materials. The multilayer filter 103 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 101, and 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 cross-section of the photodetector 10.

[0042] The multilayer filter 103 is used to allow light to pass through the target detection band, which is the detection band of the photodetector 10.

[0043] The thin film materials in the multilayer filter 103 include, but are not limited to, at least two materials such as silicon oxide, silicon nitride, aluminum oxide, niobium oxide, magnesium fluoride, and amorphous silicon. The type of thin film material in the multilayer filter 103 can be related to the target detection band. Taking the target detection band as an example (infrared or near-infrared band), the at least two thin film materials in the multilayer filter 103 can be, for example, silicon dioxide and amorphous silicon, and the multilayer filter 103 can be formed by alternating stacks of silicon dioxide and amorphous silicon. (See reference...) Figure 4 , Figure 4 A schematic diagram of the transmittance of infrared light by a multilayer film filter composed of alternating stacks of silicon dioxide and amorphous silicon is shown. This multilayer film filter has high transmittance and low reflection characteristics for near-infrared light, and low transmittance and high reflection characteristics for light in other bands besides near-infrared light, thus forming a narrowband bandpass filter that only allows near-infrared light to pass through.

[0044] The number of thin film layers in the multilayer filter 103 is greater than or equal to two, and the number of thin film layers in the multilayer filter 103 can be set based on the requirements of photoelectric performance parameters. The more thin film layers in the multilayer filter 103, the better the performance of the multilayer filter 103. For cost and feasibility considerations, the total thickness of the multilayer filter 103 is less than or equal to 5 micrometers.

[0045] 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.

[0046] A dielectric material with a refractive index lower than a preset refractive index can be filled between the substrate 101 and the multilayer filter 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.

[0047] 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. The reflective structure 102 is used to reflect light within the substrate 101.

[0048] The deep trench isolation structure 104 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.

[0049] 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 5For example, the incident light is filtered by a multilayer film filter and then enters the substrate to form light ray a1. Light ray a1 propagates to the reflective structure, and the propagation direction of the reflected light is as shown by light ray a2.

[0050] Combination Figure 2 and Figure 5 As can be seen, the photodetector includes a substrate, a reflective structure, a multilayer filter, and a deep trench isolation structure surrounding the substrate. The reflective structure is located on the first side of the second surface of the substrate. The second surface is the surface opposite to the first surface in the depth direction, and the first side is the side facing away from the interior of the substrate. The multilayer filter is a multilayer thin film structure formed by alternating stacking of at least two thin film materials. The multilayer filter is located on the first side of the first surface of the substrate in the depth direction. The multilayer filter is used to allow light of the target detection band to pass through, which is the detection band of the photodetector. The reflective structure reflects the light entering the substrate through the multilayer filter, extending the optical path of the light within the substrate, thereby increasing the light absorption efficiency of the photodetector.

[0051] In some possible designs, the aforementioned multilayer filter 103 is integrated onto the substrate 101 using a filter integration process. Filter integration refers to the technology of integrating filters and semiconductor components within the same chip or package. Filter integration processes may include substrate preparation, photolithography and etching, thin film deposition, interconnection, and packaging.

[0052] By integrating multilayer filters directly onto a substrate using filter integration technology, the module structure can be simplified and manufacturing costs reduced.

[0053] In some possible designs, light in the target detection band is reflected at the first interface of the multilayer filter 103. The first interface of the multilayer filter 103 is the interface of the multilayer filter 103 near the first surface of the substrate 101. The reflectivity of the light in the target detection band at the first interface of the multilayer filter 103 is positively correlated with the incident angle of the light in the target detection band at the first interface of the multilayer filter 103. That is, the larger the incident angle of the light in the target detection band at the first interface of the multilayer filter 103, the greater the reflectivity of the light in the target detection band at the first interface of the multilayer filter 103.

[0054] Taking the multilayer filter 103, which is a multilayer filter composed of alternating layers of silicon dioxide and amorphous silicon, as an example, the relationship curve between its reflectivity and incident angle is as follows: Figure 6 As shown, by Figure 6It can be seen that when the incident angle is 0~15 degrees, the multilayer filter has a reflectivity of less than 10% for light with a wavelength of 910nm; when the incident angle is 30 degrees, the multilayer filter has a reflectivity of 60% for light with a wavelength of 910nm; and when the incident angle is 45 degrees, the multilayer filter has a reflectivity of nearly 100% for light with a wavelength of 910nm.

[0055] The reflectivity of light at the interface of a multilayer filter is positively correlated with the incident angle of the light at the interface, which helps to fully reflect the light.

[0056] Specifically, when the incident angle of the light in the target detection band at the first interface is greater than a preset angle, the reflectivity of the light in the target detection band at the first interface is greater than a preset reflectivity. For example, the preset angle is, for example, 30°, and the preset reflectivity is, for example, 60%.

[0057] Multilayer film filters have high reflectivity for light incident at large angles, which helps to fully reflect the light.

[0058] In some possible designs, such as Figure 2 and 3 As shown, the deep trench isolation structure 104 described above is filled with at least two materials. The at least two materials filling the deep trench isolation structure 104 include an insulating dielectric material and a metallic material. The metallic material separates the insulating dielectric material into inner and outer layers within the deep trench isolation structure 104. The inner layer of the insulating dielectric material surrounds the substrate 101, and the outer layer surrounds the metallic material. The insulating dielectric material filling the deep trench isolation structure 104 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 metallic material filling the deep trench isolation structure 104 is used for optical isolation, and this metallic material includes, but is not limited to, metallic materials such as tungsten and copper.

[0059] 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.

[0060] Please see next. Figures 7-10 , Figures 7-10 This is a schematic diagram of another photodetector provided in an embodiment of this application, wherein, Figure 7 and Figure 9 The diagram shown is a vertical cross-sectional view of another photodetector provided in an embodiment of this application. Figure 8 and Figure 10 The diagram shown is a cross-sectional view of another photodetector provided in this application embodiment at the substrate.

[0061] like Figures 7-10 As shown, the photodetector 20 includes a substrate 201, a reflective structure 202, a multilayer filter 203, a deep trench isolation structure 204 surrounding the substrate 201, and a light-scattering structure 205, wherein: For a description of the substrate 201, reflective structure 202, multilayer filter 203, and deep trench isolation structure 204 surrounding the substrate 201, please refer to the foregoing descriptions of the substrate 101, reflective structure 102, multilayer filter 103, and deep trench isolation structure 104 surrounding the substrate 101. These details will not be repeated here.

[0062] The light-diffusing structure 205 is located on the second side of the first surface of the substrate 201, which is the side facing the interior of the substrate 201.

[0063] The light-diffusing structure 205 is used to diffuse the light entering the substrate 201 after passing through the multilayer film filter 203, so that the light propagates to various areas of the substrate 201.

[0064] Irradiated Figures 7-10 The propagation path of incident light on the surface of the photodetector 20 and within the photodetector 20 can be found in [reference]. Figure 11 For example, incident light is filtered by a multilayer filter and enters the substrate, forming ray b1. Ray b1 undergoes refraction and diffraction when passing through the astigmatism structure, causing its propagation direction 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, and the reflected ray's propagation direction is shown in ray b3. Ray b3 is reflected when it reaches a reflective structure, and 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, and the reflected ray's propagation direction is shown in ray b5. Ray b5 is reflected when it reaches the interface between the multilayer filter and the low-refractive-index layer, and 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.

[0065] Combination Figures 7-11 It is known that by setting a light-scattering structure on the inner side of the incident surface of the substrate, the light-scattering structure can diffuse the incident light that enters the substrate through the multilayer film filter, thereby further extending the optical path in the substrate and increasing the light absorption efficiency of the photodetector.

[0066] In some possible designs, the aforementioned astigmatic structure 205 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.

[0067] By filling the scattering structure with a low-refractive-index dielectric material, light is prevented from propagating inside the scattering structure, allowing as much light as possible that can pass through the multilayer filter to enter the substrate.

[0068] In some possible designs, such as Figure 7 and Figure 8 As shown, the astigmatism structure 205 includes multiple inverted pyramid-shaped structures. An inverted pyramid structure refers to a three-dimensional structure resembling a cone or pyramid. The cross-sectional area of ​​the inverted pyramid structure varies with depth; specifically, the cross-sectional area of ​​the inverted pyramid 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 structures can be distributed in an array or arranged randomly on the first surface of the substrate 201.

[0069] The sloping surface of the inverted pyramid structure forms a multi-angle interface. Light entering the substrate 201 through the multilayer film filter 203 is reflected by the multi-angle interface of the inverted pyramid structure, effectively extending the propagation path of the light in the substrate.

[0070] In some possible designs, such as Figure 9 and Figure 10 As shown, the light-scattering structure 205 includes multiple shallow trench structures. The shallow trench structure is formed by etching trenches of a certain depth and width onto 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 on the first surface of the substrate 201.

[0071] The shallow trench structure can increase the surface roughness of the first surface of the substrate. Light entering the substrate 201 through the multilayer film filter 203 is scattered at the first surface, thereby extending the propagation path of the light in the substrate.

[0072] It is understood that the astigmatic structure 205 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.

[0073] Please see next. Figure 12 , Figure 12 This is a schematic diagram of another photodetector provided in an embodiment of this application. Figure 12This diagram illustrates a vertical cross-sectional structure of another photodetector provided in an embodiment of this application. Figure 12 As shown, the photodetector 30 includes a substrate 301, a reflective structure 302, a multilayer filter 303, a deep trench isolation structure 304 surrounding the substrate 301, a light-scattering structure 305, and a metal grid structure 306, wherein: For a description of the substrate 301, the reflective structure 302, the multilayer filter 303, the deep trench isolation structure 304 surrounding the substrate 301, and the light-scattering structure 305, please refer to the preceding description. Figures 2-11 The relevant descriptions will not be repeated here.

[0074] The metal grid structure 306 is located between the deep trench isolation structure 304 and the multilayer filter 303 in the depth direction, and the cross-section of the metal grid structure 306 covers the cross-section of the deep trench isolation structure 304. The metal grid structure 306 is used to block light and prevent light escape. The metal grid structure 306 can also be used to interact with light to enhance the local field strength within the substrate 301 and improve the light absorption efficiency. By setting up a metal grid, the probability of light propagating to neighboring units can be reduced, further suppressing optical crosstalk between adjacent photodetectors.

[0075] Please see next. Figure 13 , Figure 13 This is a schematic diagram of another photodetector provided in an embodiment of this application. Figure 13 This diagram illustrates a vertical cross-sectional structure of another photodetector provided in an embodiment of this application. Figure 13 As shown, the photodetector 40 includes a substrate 401, a reflective structure 402, a multilayer filter 403, a deep trench isolation structure 404 surrounding the substrate 401, a light-scattering structure 405, a padding layer 406, and a lens structure 407, wherein: For a description of the substrate 401, the reflective structure 402, the multilayer filter 403, the deep trench isolation structure 404 surrounding the substrate 401, and the light-scattering structure 405, please refer to the preceding description. Figures 2-11 The relevant descriptions will not be repeated here.

[0076] The padding layer 406 and the lens structure 407 are located on the second side of the multilayer filter 403 in the depth direction; the padding layer 406 is located between the lens structure 407 and the multilayer filter 403 in the depth direction.

[0077] The padding layer 406 can be a transparent organic material. The padding layer 406 is used to adjust the focal point of the lens structure 407 to a reasonable position.

[0078] Lens structure 407 is used to converge incident light rays into photodetector 40. Lens structure 407 may include microlenses. Microlenses may be spherical or cylindrical, and this application does not limit this.

[0079] Placing a pad layer and lens structure above the multilayer filter can enhance the light collection efficiency of the photodetector.

[0080] In some possible designs, such as Figures 2-13 As shown, the photodetector 10 also includes a metal front dielectric layer L2 and a wiring layer L3, which are located on the second 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.

[0081] 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.

[0082] 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.

[0083] By reusing the metal wiring layer to form a reflective structure, materials can be saved.

[0084] In some possible designs, the material of the aforementioned metal front dielectric layer is an insulating dielectric material.

[0085] 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.

[0086] Please see again Figure 14 , Figure 14 This is a schematic diagram of a photodetector array provided in an embodiment of this application. Figure 14 This diagram illustrates a vertical cross-sectional view of multiple photodetectors arranged adjacent to each other in a photodetector array provided in an embodiment of this application. For example... Figure 14 As shown, the photodetector array 50 includes multiple photodetectors arranged in an array, and the photodetectors can be as described above. Figure 2 , Figure 7 , Figure 9 , Figure 12 or Figure 13 As shown.

[0087] like Figure 14 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.

[0088] 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.

[0089] like Figure 14 As shown, the multilayer filter and low-refractive layer of two adjacent photodetectors in the photodetector array are connected. For a detailed introduction to the multilayer filter, please refer to the previous section. Figures 2-3 This section introduces the multilayer filter 103 and the low-refractive-index layer L1. When light enters the substrate of the photodetector and reaches the interface between the low-refractive-index layer and the multilayer filter, it is reflected back into the substrate. 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.

[0090] like Figure 14 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 2-13The 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.

[0091] The photodetector of this application can be used to manufacture electronic devices, such as image sensors, laser sensors, and other electronic devices.

[0092] This application also provides an electronic device, including an electronic device with a photodetector, the photodetector being as described above. Figures 2-13 As shown, please refer to the aforementioned... Figures 2-13 The relevant information will not be repeated here.

[0093] 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.

[0094] 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 multilayer filter, and a deep trench isolation structure surrounding the substrate, wherein: The multilayer filter is a multilayer thin film structure formed by alternating stacking of at least two thin film materials. The multilayer filter 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 multilayer filter is used to allow light in the target detection band to pass through, and the target detection band is the detection band of the photodetector. 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 multilayer filter is integrated onto the substrate using a filter integration process.

3. The photodetector according to claim 1, characterized in that, The light of the target detection band is reflected at the first interface of the multilayer filter. The first interface is the interface close to the first surface. The reflectivity of the light of the target detection band at the first interface is positively correlated with the incident angle of the light of the target detection band at the first interface.

4. The photodetector according to claim 3, characterized in that, When the incident angle of the light in the target detection band at the first interface is greater than a preset angle, the reflectivity of the light in the target detection band at the first interface 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 second side of the first surface of the substrate, the second side being 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 multiple inverted pyramidal structures and / or multiple 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 metallic material; the 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 surrounds the substrate, and the outer layer of the insulating dielectric material surrounds the metallic material.

9. The photodetector according to any one of claims 1-4, characterized in that, The photodetector also includes a metal grid structure, wherein: The metal grid structure is located between the deep trench isolation structure and the multilayer film filter in the depth direction, and the cross-section of the metal grid structure covers the cross-section of the deep trench isolation structure.

10. The photodetector according to any one of claims 1-4, characterized in that, The photodetector also includes a pad layer and a lens structure, wherein: The padding layer and the lens structure are located on the first side of the multilayer filter in the depth direction; The padding layer is located between the lens structure and the multilayer filter in the depth direction.

11. 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.

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

13. The photodetector according to claim 11, characterized in that, The material of the metal front dielectric layer is an insulating dielectric material.

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

15. An electronic device, characterized in that, It includes electronic devices, said electronic devices having a photodetector as described in any one of claims 1-13.

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