Pixel sensor structure and sensing system

Abstract

Some embodiments of the present disclosure include pixel sensor structures and methods of manufacture. The pixel sensor structure includes a lens structure, a photodiode sensor structure, and a light spacer structure between the lens structure and the photodiode sensor structure. Compared with another pixel sensor structure comprising a photodiode sensor structure without a lens structure and a light spacing structure, the lens structure redirects near-infrared light to the photodiode sensor structure through the light spacing structure, and quantum efficiency performance can be improved. In addition, anti-reflection coatings in different configurations can be included in the whole pixel sensor structure, so that the quantum efficiency performance of the photodiode sensor structure is further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of semiconductor components, in particular to a kind of pixel sensor structure and sensing system. BACKGROUND

[0002] Complementary metal oxide semiconductor (CMOS) image sensors convert light energy into electrical energy using light-sensitive CMOS circuits. The light-sensitive CMOS circuits can include photodiodes formed in a silicon substrate. When the photodiodes are exposed to light, charge (called photocurrent) is induced in the photodiodes. The photodiodes can be coupled to switching transistors that are used to sample the charge of the photodiodes. Color can be confirmed by placing filters on the light-sensitive CMOS circuits.

[0003] Pixel sensors of CMOS image sensors often receive light according to three primary colors: red, green, and blue (R, G, B). Pixel sensors that perform light sensing can define a color for each color by using a color filter that lets a specific color of light wavelength pass to the photodiode. Some pixel sensors can include a near infrared (NIR) pass filter that blocks visible light and lets near infrared light pass to the photodiode. SUMMARY

[0004] Embodiments of the utility model provide a kind of pixel sensor structure, it includes photodiode region, lens structure and light interval structure. Photodiode region has photodiode sensor structure in semiconductor layer. Lens structure is separate from the photodiode region, and with the convex surface of substantially face the photodiode region. Light interval structure is between the photodiode region and the lens structure, wherein the light interval structure is configured to maintain the interval distance between lens structure bottom and photodiode region top.

[0005] Embodiments of the present application provide a sensing system that includes an image sensor element. The image sensor element includes a pixel sensor structure. The pixel sensor structure includes a lens structure, a single photon avalanche photodiode structure, a multi-layer structure, and at least one anti-reflective coating. The multi-layer structure has a conductive material that transmits near-infrared light between the lens structure and the single photon avalanche photodiode structure. The at least one anti-reflective coating is in a near-infrared light path between a near-infrared light source and the single photon avalanche photodiode structure.

[0006] Based on the above, compared to another pixel sensor structure that includes a photodiode sensor structure without a lens structure and a light spacing structure, the lens structure redirects near-infrared light through the light spacing structure to the photodiode sensor structure, which can improve quantum efficiency performance. In addition, different configurations of anti-reflective coatings can be included in the entire pixel sensor structure to further improve the quantum efficiency performance of the photodiode sensor structure.

[0007] In order to make the above features and advantages of the present application more obvious and easy to understand, the following embodiments are described in detail, and the drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a diagram of an exemplary pixel array described in the present disclosure.

[0009] Figures 2A-2D is a diagram of an exemplary embodiment of a pixel sensor structure described in the present disclosure.

[0010] Figure 3 is a diagram of an exemplary embodiment of a system including a pixel sensor structure described in the present disclosure.

[0011] Figures 4A-4I is a diagram of a series of exemplary semiconductor process operations to form a pixel sensor structure described in the present disclosure.

[0012] Figure 5 is a flowchart of an exemplary process related to forming a pixel sensor structure described in the present disclosure.

[0013] BRIEF DESCRIPTION OF DRAWINGS

[0014] 100: pixel array;

[0015] 102: pixel sensors;

[0016] 200: pixel sensor structure;

[0017] 202: photodiode region;

[0018] 204: photodiode sensor structure;

[0019] 206: semiconductor layer;

[0020] 208a, 208b: isolation structure;

[0021] 210: multi-layer structure;

[0022] 212: optical spacer structure;

[0023] 214: lens structure;

[0024] 216: convex surface;

[0025] 218a, 218b, 218c: anti-reflective coating layer;

[0026] 300: system;

[0027] 302: light source;

[0028] 304: image sensor device;

[0029] 306: light;

[0030] 308: sensing region, extension region;

[0031] 310a, 310b, 310c: reflection;

[0032] 400: semiconductor processing operations;

[0033] 402: cavity;

[0034] 500: process;

[0035] 510, 520, 530: Block;

[0036] D1, D2: Width;

[0037] D3, D4, D5, D6: Thickness;

[0038] D7: Radius of curvature. Detailed Implementation

[0039] The following disclosure provides many different embodiments or examples to implement the various features of this invention. The following disclosure describes specific examples of the various components and their arrangements for simplification. Of course, these specific examples are not intended to be limiting. For example, if the present invention describes a first feature formed on or above a second feature, it may include embodiments where the first and second feature are in direct contact, or embodiments where an additional feature is formed between the first and second feature, so that the first and second feature may not be in direct contact. Furthermore, the present invention may reuse references and / or text in various examples. This repetition is for the purpose of brevity and clarity, and does not itself indicate a relationship between the various embodiments and / or configurations discussed.

[0040] Spatial relative terms, such as “below,” “under,” “lower,” “above,” “above,” etc., may be used herein for descriptive convenience to describe the relationship of one element or feature to another, as shown in the figure. Spatial relative terms are intended to cover different orientations of elements in use or operation, in addition to those shown in the figure. Elements may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein may be interpreted accordingly.

[0041] The performance of a photodiode sensor structure, including those within a pixel sensor structure, can be quantified using quantum efficiency (QE). Quantum efficiency, expressed as a ratio or percentage, represents the efficiency with which photons are converted into photoelectrons (electrons generated by absorbing photons) within the photodiode sensor structure. In other words, quantum efficiency quantifies the ability of a photodiode sensor structure to convert incident photons into usable electrical signals. Furthermore, quantum efficiency directly affects the sensitivity performance of a pixel sensor structure.

[0042] In some cases, a photodiode sensor structure can have intrinsically low quantum efficiency for receiving and converting near infrared light (e.g., electromagnetic waves having a wavelength between approximately 700 nanometers (nm) and 2500 nm) into photocurrent. To improve quantum efficiency, the photodiode sensor structure can include a germanium single-photon avalanche photodiode (GeSPAD) sensor structure. In addition, the photodiode sensor structure can be surrounded by an isolation grid to reduce optical crosstalk and / or electrical crosstalk with adjacent pixel sensor structures. However, such modifications can not significantly improve quantum efficiency performance of the photodiode sensor structure and result in the pixel sensor structure failing to meet quantum efficiency performance thresholds and / or sensitivity performance thresholds associated with applications configured to detect near infrared light.

[0043] Some embodiments of the present disclosure include a pixel sensor structure and a forming method. The pixel sensor structure includes a lens structure, a photodiode sensor structure, and a light spacing structure between the lens structure and the photodiode sensor structure. Compared to another pixel sensor structure including a photodiode sensor structure without the lens structure and the light spacing structure, the lens structure can improve quantum efficiency performance by redirecting near infrared light through the light spacing structure to the photodiode sensor structure. In addition, different configurations of anti-reflective coatings can be included throughout the pixel sensor structure to further improve quantum efficiency performance of the photodiode sensor structure.

[0044] In this way, quantum efficiency performance of the photodiode sensor structure and / or sensitivity performance of the pixel sensor structure can be improved to meet one or more performance thresholds associated with applications that sense images in low-lighting environments. By meeting the one or more performance thresholds, the amount of resources (e.g., labor, raw materials, semiconductor process tools, and / or computing resources consumed to achieve production yields corresponding to the one or more performance thresholds) supporting the use of the pixel sensor structure 200 can be reduced.

[0045] Figure 1This is a schematic diagram of an exemplary pixel array 100 (or a portion thereof). Pixel array 100 may be included in an image sensor, such as a complementary metal oxide semiconductor (CMOS) image sensor, a back-side illumination (BSI) CMOS image sensor, or other types of image sensors. In some embodiments, the image sensor is an image sensor configured to detect near-infrared light in low-light applications, including in other examples such as surveillance systems, night vision systems, or automotive cameras.

[0046] Figure 1 A top view of pixel array 100 is shown. (As shown) Figure 1 As shown, the pixel array 100 may include multiple pixel sensors 102. Figure 1 It also includes section AA, which is used for explanation. Figures 2A-4I A side view of a pixel sensor structure, wherein the pixel sensor structure may correspond to one or more pixel sensors 102.

[0047] like Figure 1 As further shown, the pixel sensor 102 may be arranged in a grid. In some embodiments, the pixel sensor 102 is square (as shown in the example of FIG2). In some embodiments, the pixel sensor 102 includes other shapes, such as circular, octagonal, rhomboid and / or other shapes.

[0048] Pixel sensor 102 may be configured to sense and / or accumulate incident light (e.g., light directed toward pixel array 100). For example, pixel sensor 102 may absorb and accumulate photons of the incident light in a photodiode. Accumulating photons in a photodiode may generate a charge representing the intensity or brightness of the incident light (e.g., a larger amount of charge may correspond to a larger intensity or brightness, while a smaller amount of charge may correspond to a lower intensity or brightness).

[0049] In some embodiments, the pixel array 100 may be electrically connected to an interconnect metallization stack (not shown) of an image sensor. This interconnect metallization stack may electrically connect the pixel array 100 to control circuitry that can be used to measure the accumulation of incident light in the pixel sensor 102 and convert the measured value into an electrical signal.

[0050] like Figures 2A-2D , Figure 3 , Figures 4A-4I and Figure 5As detailed, one or more pixel sensors 102 of the pixel array 100 can include a pixel sensor structure designed to detect near-infrared light. The pixel sensor structure can include one or more features, such as a lens structure, a light spacing structure, a photodiode sensor structure, and / or an anti-reflective coating dispersed across one or more material interfaces within the pixel sensor structure. The arrangement of these features can direct near-infrared light through the pixel sensor structure and increase the amount of near-infrared light (e.g., photons) absorbed by the photodiode sensor structure.

[0051] As shown above, Figure 1 are provided by way of example only. Other embodiments can vary from the description of Figure 1 .

[0052] Figures 2A-2D is a diagram that describes an example embodiment of a pixel sensor structure 200 in the present disclosure. The pixel sensor structure 200 can correspond to one or more pixel sensors 102 related to the Figure 1 . Moreover, Figures 2A-2D , Figure 3 and 4A - Figure 4I The pixel sensor structure 200 is illustrated using the A-A section in Figure 1 .

[0053] As shown in the example embodiment of Figure 2A , the pixel sensor structure 200 includes a photodiode region 202 that includes a photodiode sensor structure 204 in a semiconductor layer 206 (e.g., the photodiode sensor structure 204 is embedded in the semiconductor layer 206). The photodiode sensor structure 204 includes regions that are doped with ions of various types to form a p-n junction or a PIN junction (e.g., a junction between a p-type portion, an intrinsic type (or undoped) portion, and an n-type portion). For example, an ion implantation element tool can be used to implant n-type dopants to form a first portion of the photodiode (e.g., the n-type portion) and to implant p-type dopants to form a second portion of the photodiode (e.g., the p-type portion). The photodiode sensor structure 204 can be configured to absorb photons of incident light. The absorption of the photons causes the photodiode sensor structure 204 to accumulate charge (known as a photocurrent) due to the photoelectric effect. Here, the photons strike the photodiode region 202, causing the release of electrons from the photodiode sensor structure 204. The release of the electrons results in the formation of electron-hole pairs, where the electrons migrate toward a cathode of the photodiode sensor structure 204 and the holes migrate toward an anode, thereby generating the photocurrent.

[0054] In certain embodiments, the photodiode sensor structure 204 corresponds to a single-photon avalanche photodiode structure with the capability of detecting a single photon (e.g., the smallest unit of light), with a sensitivity and precision capable of detecting near-infrared light. In such embodiments, the photodiode sensor structure 204 can utilize an avalanche effect to amplify the electrical signal generated by a single photon. As part of the avalanche effect, a single photon can hit the photodiode sensor structure 204 and generate a pair of electron-hole. An electric field within the photodiode sensor structure 204 can accelerate these charge carriers, causing impact ionization, resulting in additional pairs of electron-hole, causing an avalanche of charge carriers and amplifying the output signal.

[0055] To initiate the avalanche effect, the photodiode sensor structure 204 can include one or more combinations of III-V group chemical elements or materials with a bandgap energy level suitable for initiating the avalanche effect. For example, the photodiode sensor structure 204 can include germanium (Ge), in which case the photodiode sensor structure 204 can be referred to as a germanium single-photon avalanche (GeSPAD) structure. Alternatively, the photodiode sensor structure 204 can include gallium arsenide (GaAs) or indium gallium arsenide (InGaAs), among other examples.

[0056] The semiconductor layer 206 can include a semiconductor material suitable for forming integrated circuit elements (e.g., transistors, amplifiers, analog-to-digital converters, signal processors, logic), which can be included in the semiconductor elements including the photodiode sensor structure 204. For example, the semiconductor material can include silicon (Si), in which case the semiconductor layer 206 can be referred to as a silicon layer. Alternatively, the semiconductor material can include gallium arsenide (GaAs), indium gallium arsenide (InGaAs), amorphous silicon (a-Si), or silicon carbide (SiC), among other examples.

[0057] As Figure 2AAs further shown, the photodiode region 202 further includes an isolation structure 208a, an isolation structure 208b, and a multi-layer structure 210. As shown, the isolation structure 208a and the isolation structure 208b are located on opposite sides of the photodiode sensor structure 204. As shown, the isolation structure 208a and the isolation structure 208b are located on the surface of the semiconductor layer 206. Figure 2A As further shown, the multi-layer structure 210 is located on the surface of the semiconductor layer 206. Figure 2A As further shown, the multi-layer structure 210 is located on the surface of the semiconductor layer 206.

[0058] In certain embodiments, the isolation structure 208a and the isolation structure 208b are included in a grid layout that extends to the perimeter of the pixel sensor structure 200. The isolation structure 208a and the isolation structure 208b (e.g., deep trench backside isolation structures) can provide optical isolation by blocking or preventing light from spreading or bleeding out of the pixel sensor structure 200 to adjacent pixel sensor structures, thereby reducing optical cross-talk. Additionally, or alternatively, the isolation structure 208a and the isolation structure 208b can provide electrical isolation by reducing the likelihood of exchanging charge carriers (e.g., electrons or holes) with adjacent pixel sensor structures, thereby reducing electrical cross-talk. In certain embodiments, the isolation structure 208a and / or the isolation structure 208b includes a dielectric material, such as silicon dioxide (SiO2), silicon nitride (SiN), or other suitable dielectric material, etc.

[0059] The multi-layer structure 210 can include one or more layers of conductive material for integrated circuit elements located on or in the semiconductor layer 206. In certain embodiments, the conductive material can be a transparent conductive oxide material that is transparent to near-infrared light, such as indium tin oxide (ITO), etc. Additionally, or alternatively, the multi-layer structure 210 can include one or more layers of dielectric material to isolate and / or separate the one or more layers of conductive material. In certain embodiments, the dielectric material is a dielectric material that is transparent to near-infrared light, such as silicon dioxide (SiO2) or aluminum dioxide (Al2O3), etc.

[0060] As shown, the multi-layer structure 210 includes a layer of transparent conductive oxide material 210a and a layer of dielectric material 210b. As shown, the layer of transparent conductive oxide material 210a is located on the surface of the semiconductor layer 206. As shown, the layer of dielectric material 210b is located on the layer of transparent conductive oxide material 210a. Figure 2AAs shown, the optical spacer structure 212 is located above the photodiode region 202. In some embodiments, the optical spacer structure 212 is located on the multilayer structure 210. The optical spacer structure 212 may comprise a polymeric material that is transparent to near-infrared light, such as polymethyl methacrylate (PMMA), polycarbonate, polyethylene (PE), polyvinylidene fluoride (PVDF), or other suitable polymeric materials. Alternatively, the optical spacer structure 212 may comprise a resinic material that is transparent to infrared light, such as epoxy resin or other suitable resin materials. Or, the optical spacer structure 212 may comprise an organic material that is transparent to near-infrared light, such as cyclo-olefin copolymer (COC), cyclo-olefin polymer (COP), or other suitable organic materials.

[0061] like Figure 2A As shown, a lens structure 214 with a protruding surface 216 is located above the optical spacer structure 212. The protruding surface 216 has a convex curvature extending approximately away from the optical spacer structure 212 and / or the photodiode sensor structure 204. In some embodiments, the lens structure 214 is located on the optical spacer structure 212. The lens structure 214 may comprise a polymeric material that is transparent to near-infrared light, such as polymethyl methacrylate (PMMA), polycarbonate, polyethylene (PE), polyvinylidene fluoride (PVDF), or other suitable polymeric materials. Alternatively, the lens structure 214 may comprise a resinic material that is transparent to infrared light, such as epoxy resin or other suitable resin materials. Or, the lens structure 214 may comprise an organic material that is transparent to near-infrared light, such as a cyclic olefin copolymer (COC), a cyclic olefin polymer (COP), or other suitable organic materials.

[0062] like Figure 2A As shown, the optical spacer structure 212 is located between the lens structure 214 and the photodiode sensor structure 204. In some embodiments, the optical spacer structure 212 is configured to maintain a spacing distance between the bottom surface of the lens structure 214 and the top surface of the photodiode region 202 including the photodiode sensor structure 204. This spacing distance may change the focal length of the lens structure 214 and optimize the dispersion of light on the surface of the photodiode sensor structure 204.

[0063] like Figure 2AAs shown, an anti-reflective coating 218a is located on the convex surface 216. The anti-reflective coating 218a can include a material that reduces the reflection of near-infrared light from the convex surface 216 and promotes the passage of near-infrared light through the lens structure 214. Reducing the reflection of near-infrared light and promoting the passage of near-infrared light through the lens structure 214 can increase the absorption of photons by the photodiode sensor structure 204. Examples of such materials include oxide materials, such as tantalum pentoxide (Ta2O5) or other materials suitable for reducing the reflection of near-infrared light, etc.

[0064] Figure 2B Another example embodiment of the pixel sensor structure 200 is shown. As compared to the embodiment in Figure 2A the embodiment in Figure 2B in which the pixel sensor structure 200 includes an anti-reflective coating 218b on the semiconductor layer 206 and an anti-reflective coating 218c on the photodiode sensor structure 204.

[0065] Figure 2C Another example embodiment of the pixel sensor structure 200 is shown. As compared to the embodiment in Figure 2A and / or the embodiment in Figure 2B in which the pixel sensor structure 200 includes an anti-reflective coating 218b on the semiconductor layer 206 and an anti-reflective coating 218c on the photodiode sensor structure 204. Figure 2C in which the width of the photodiode sensor structure 204 can be increased to expand the effective area of the photodiode sensor structure 204 to receive photons to improve the quantum efficiency performance of the photodiode sensor structure 204. Additionally, or alternatively, as compared to the embodiment in Figure 2A and Figure 2B in which the thickness of the photodiode sensor structure 204 can be increased to improve the sensitivity performance of the photodiode sensor structure 204.

[0066] Figure 2D Another example embodiment of the pixel sensor structure 200 is shown that incorporates features related to the embodiments in Figures 2A-2C (e.g., increased thickness / width of the photodiode sensor structure 204, the light spacing structure 212, the lens structure 214, the convex surface 216, and the anti-reflective coatings 218a-218c). As described in more detail in Figure 3 the performance thresholds associated with image sensing applications used in low light environments (e.g., image sensing applications that detect near-infrared light) and / or incorporating different features. Additionally, or alternatively, and as described in more detail in Figure 3 the performance thresholds associated with image sensing applications used in low light environments (e.g., image sensing applications that detect near-infrared light) and / or incorporating different features. Additionally, or alternatively, and as described in more detail in

[0067] As Figures 2A-2D described, embodiments of a pixel sensor structure (e.g., pixel sensor structure 200) include a photodiode region (e.g., photodiode region 202) having a photodiode sensor structure (e.g., photodiode sensor structure 204) in a semiconductor layer (e.g., semiconductor layer 206). The pixel sensor structure includes a lens structure (e.g., lens structure 214) separate from the photodiode sensing region and having a generally convex surface (e.g., convex surface 216) generally convex away from the photodiode region. The pixel sensor structure includes a light spacing structure (e.g., light spacing structure 212). In some embodiments, the light spacing structure is configured to maintain a separation distance between a bottom of the lens structure and a top of the photodiode region.

[0068] Figures 2A-2D The number and arrangement of structures shown in the figures are provided as one or more examples. In practice, there can be additional structures, fewer structures, different structures, or differently arranged structures. Figures 2A-2D In addition, portions of structures shown as separate in the figures can actually be integrated together, and portions shown as integrated together can actually be separate. In addition, reference numerals can be repeated among the figures to indicate corresponding or analogous structures throughout the figures. Figures 2A-2D Two or more structures shown in the figures can be implemented within a single element, or Figures 2A-2D a single structure shown in the figures can be implemented as multiple elements, distributed elements, or the like. Additionally, or in the alternative, a set of structures (e.g., one or more structures) can perform one or more functions attributed herein to another set of structures.

[0069] Figure 3 FIG. 3 is a schematic diagram of an exemplary embodiment of a system 300 including a pixel sensor structure (e.g., pixel sensor structure 200) described in this disclosure. In some embodiments, system 300 can be a system for low light applications, such as a surveillance system, a night vision system, or an automotive photography system, among others. As Figure 3 shown, the system can include a light source 302 (e.g., a near-infrared light source). Additionally, or in the alternative, as Figure 3 shown, pixel sensor structure 200 can be part of an image sensor element 304 (e.g., a complementary metal-oxide-semiconductor (CMOS) image sensor, a back-side illuminated (BSI) CMOS image sensor element, or another type of image sensor element).

[0070] In Figure 3In the photodiode sensor structure 204, light 306 (e.g., near-infrared light reflected by the target to be imaged by the system 300) is received by light 306 projected by light source 302. The light 306 may be redirected by the protruding surface 216 of lens structure 214, passing through lens structure 214, optical spacer structure 212, multilayer structure 210, and a portion of semiconductor layer 206, to photodiode sensor structure 204.

[0071] like Figure 3 As shown, the pixel sensor structure 200 has a width D1, and the photodiode sensor structure 204 has a width D2. The width D1 (e.g., a dimension of the pixel sensor structure 200) can range from approximately 9 micrometers (μm) to approximately 11 μm, and so on. Based on the width D1, and as... Figure 2C The width D2 can be selected and / or increased to not exceed the width D1 and / or without interfering with the widths of isolation structures 208a and / or 208b (e.g., width D2 can be in the range of approximately 7 μm to approximately 9 μm). By increasing width D2, an extension region 308 of the photodiode sensor structure 204 can be formed to increase the effective area of ​​the photodiode sensor structure 204 and receive additional light (e.g., photons of light 306). Selecting a width D2 that exceeds width D1 may prevent miniaturization of the pixel sensor structure 200. Alternatively, selecting a width D2 that interferes with isolation structures 208a and / or 208b may reduce the effectiveness of isolation structures 208a and / or 208b (e.g., reducing the effect of isolation structures 208a and / or 208b in providing electrical and / or optical isolation between the pixel sensor structure 200 and other adjacent pixel structures). However, other values ​​and / or ranges for widths D1 and D2 are within the scope of this disclosure.

[0072] like Figure 3 As further shown, the photodiode sensor structure 204 includes a thickness D3. Similar to... Figure 2C As described in the relevant description, the thickness D3 can be selected and / or increased to improve the ability of the photodiode sensor structure 204 to detect light 306 in the photodiode sensor structure 204 (e.g., photons in the sensing region 308) and to meet the quantum efficiency performance threshold. For example, the thickness D3 can be selected and / or increased such that the thickness D3 is greater than or equal to approximately 3 micrometers to increase the ability to detect photons and to make the photodiode sensor structure 204 reach the quantum efficiency performance threshold. Selecting and / or decreasing the thickness D3 to at least approximately 3 micrometers may reduce the ability to detect photons and cause the photodiode sensor structure 204 to fail to reach the quantum efficiency performance threshold. However, other values ​​and / or ranges of the thickness D3 are within the scope of this disclosure.

[0073] like Figure 3 As shown, the anti-reflective coating 218a is located on the protruding surface 216 and in the light 306 path between the light source 302 and the photodiode sensor structure 204. In some embodiments, the anti-reflective coating 218a reduces and / or eliminates reflections 310a of light 306 from the protruding surface 216 to reduce loss and increase the amount of light 306 transmitted through the lens structure 214.

[0074] like Figure 3 As shown, the anti-reflective coating 218b is located on the semiconductor layer 206 and in the light 306 path between the light source 302 and the photodiode sensor structure 204. In some embodiments, the anti-reflective coating 218b reduces and / or eliminates reflections 310b from the semiconductor layer 206 to reduce losses and increase the amount of light 306 transmitted through the optical spacer structure 212.

[0075] like Figure 3 As shown, the anti-reflective coating 218c is located on the photodiode sensor structure 204 and in the light 306 path between the light source 302 and the photodiode sensor structure 204. In some embodiments, the anti-reflective coating 218c reduces and / or eliminates reflections 310c from the photodiode sensor structure 204 to reduce losses and increase the amount of light 306 absorbed by the photodiode sensor structure 204.

[0076] In certain embodiments, the thickness D4 of the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c can be selected depending on the material included in the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c and the type of light for which reflection is desired to be reduced. For example, for the case where the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c includes a tantalum pentoxide material and the light 306 is near-infrared light, the thickness D4 can be in the range of approximately 0.1 microns to approximately 0.4 microns. Selecting a thickness D4 less than approximately 0.1 microns can result in the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c not being effective in reducing and / or eliminating reflection of the light 306 (e.g., the reflection 310a, the reflection 310b, and / or the reflection 310c) and significantly reducing the amount of light 306 passing through the lens structure 214, the light spacing structure 212, and / or the semiconductor layer 206 to the photodiode sensor structure 204. Selecting a thickness D4 between approximately 0.1 microns and 0.4 microns can enable the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c to effectively reduce and / or eliminate reflection of the light 306 and maintain a transmittance that does not significantly reduce the amount of light 306 passing through the lens structure 214, the light spacing structure 212, and / or the semiconductor layer 206 to the photodiode sensor structure 204. Selecting a thickness D4 greater than 0.4 microns can result in the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c becoming non-transmissive and reducing the amount of light 306 passing through the lens structure 214, the light spacing structure 212, and / or the semiconductor layer 206 to the photodiode sensor structure 204. However, other combinations of materials for the anti-reflective coating 218a, the anti-reflective coating 218b, and / or the anti-reflective coating 218c, values and ranges for the thickness D4, and types of light are within the scope of the present disclosure.

[0077] As shown in FIG. 2A, the lens structure 214 includes a thickness D6. As an example, the thickness D5 can be in the range of approximately 5 microns to approximately 8 microns and the thickness D6 can be in the range of approximately 3 microns to approximately 8 microns. In certain embodiments, the thickness D5 and the thickness D6 are selected depending on the size (e.g., the width Dl) of the pixel sensor structure 200. Figure 3 As shown in FIG. 2A, the lens structure 214 includes a thickness D6. As an example, the thickness D5 can be in the range of approximately 5 microns to approximately 8 microns and the thickness D6 can be in the range of approximately 3 microns to approximately 8 microns. In certain embodiments, the thickness D5 and the thickness D6 are selected depending on the size (e.g., the width Dl) of the pixel sensor structure 200. Figure 3 As shown in FIG. 2A, the lens structure 214 includes a thickness D6. As an example, the thickness D5 can be in the range of approximately 5 microns to approximately 8 microns and the thickness D6 can be in the range of approximately 3 microns to approximately 8 microns. In certain embodiments, the thickness D5 and the thickness D6 are selected depending on the size (e.g., the width Dl) of the pixel sensor structure 200.

[0078] As shown in FIG. 2A, the lens structure 214 includes a thickness D6. As an example, the thickness D5 can be in the range of approximately 5 microns to approximately 8 microns and the thickness D6 can be in the range of approximately 3 microns to approximately 8 microns. In certain embodiments, the thickness D5 and the thickness D6 are selected depending on the size (e.g., the width Dl) of the pixel sensor structure 200. Figure 3As shown, the convex surface 216 has a radius of curvature D7. In some embodiments, this radius of curvature D7 can have a ratio based on the width D2 of the photodiode sensor structure 204 and the offset of the convex surface 216 from the photodiode sensor structure 204, where the offset is the biproduct of the thickness D5 and the thickness D6. For example, where the width D2 is an increasing width in the range of about 7 microns to about 9 microns, the thickness D5 is in the range of about 5 microns to about 8 microns, and the thickness D6 is in the range of about 3 microns to about 8 microns, the ratio of the radius of curvature D7 to the width D2 (D7:D2) can be included in the range of about 2:5 to about 3:5.

[0079] Selecting a ratio of D7:D2 less than about 2:5 can result in the light 306 passing through the lens structure 214, the light spacer structure 212, and the semiconductor layer 206 being focused in an area of the photodiode sensor structure 204 that is substantially less than the available area of the photodiode sensor structure 204, thereby reducing the quantum efficiency performance of the photodiode sensor structure 204 and causing the pixel sensor structure 200 to fail to meet a quantum efficiency performance threshold. Additionally, or alternatively, selecting a ratio of D7:D2 less than about 2:5 can result in inefficient use of materials to form the pixel sensor structure 200. Selecting a ratio of D7:D2 between about 2:5 and about 3:5 can result in the light 306 passing through the lens structure 214, the light spacer structure 212, and the semiconductor layer 206 being focused in an area of the photodiode sensor structure 204 that is about equal to the available area of the photodiode sensor structure 204, thereby improving the quantum efficiency performance of the photodiode sensor structure 204 and causing the photodiode sensor structure 204 to meet a quantum efficiency performance threshold. Additionally, or alternatively, selecting a ratio of D7:D2 between about 2:5 and about 3:5 can result in efficient use of materials to form the pixel sensor structure 200. Selecting a ratio of D7:D2 greater than about 3:5 can result in the light 306 passing through the lens structure 214, the light spacer structure 212, and the semiconductor layer 206 being focused in an area that exceeds the available area of the photodiode sensor structure 204, thereby reducing the quantum efficiency performance of the photodiode sensor structure 204 and causing the photodiode sensor structure 204 to fail to meet a quantum efficiency performance threshold. Additionally, or alternatively, selecting a ratio of D7:D2 greater than about 3:5 can result in inefficient use of materials to form the pixel sensor structure 200 and / or prevent miniaturization of the pixel sensor structure 200. However, other values and ranges of D7:D2 are within the scope of the present disclosure.

[0080] As shown, the convex surface 216 has a radius of curvature D7. In some embodiments, this radius of curvature D7 can have a ratio based on the width D2 of the photodiode sensor structure 204 and the offset of the convex surface 216 from the photodiode sensor structure 204, where the offset is the biproduct of the thickness D5 and the thickness D6. For example, where the width D2 is an increasing width in the range of about 7 microns to about 9 microns, the thickness D5 is in the range of about 5 microns to about 8 microns, and the thickness D6 is in the range of about 3 microns to about 8 microns, the ratio of the radius of curvature D7 to the width D2 (D7:D2) can be included in the range of about 2:5 to about 3:5. Figures 2A-2D and Figure 3Embodiments of the system (e.g., system 300) include an image sensor element (e.g., image sensor element 304) that includes a pixel sensor structure (e.g., pixel sensor structure 200). The pixel sensor structure includes a lens structure (e.g., lens structure 214), a single-photon avalanche photodiode structure (e.g., photodiode sensor structure 204), a multi-layer structure (e.g., multi-layer structure 210) having a conductive material that is transparent to near-infrared light between the lens structure and the single-photon avalanche photodiode structure, and at least one anti-reflective coating (e.g., anti-reflective coating 218a, anti-reflective coating 218b, and / or anti-reflective coating 218b) on a path of the near-infrared light between a near-infrared light source (e.g., light source 302) and the single-photon avalanche photodiode structure.

[0081] As shown above, Figure 3 are for example only. Other embodiments can differ from what is described with regard to Figure 3 .

[0082] Figures 4A-4I is an exemplary diagram of a series of semiconductor process operations 400 for forming a pixel sensor structure (e.g., pixel sensor structure 200) as described in the present disclosure. The series of semiconductor process operations 400 can be performed by one or more semiconductor processes using a combination of deposition techniques, optical lithography techniques, and / or etching techniques to form the pixel sensor structure.

[0083] As shown above, Figure 4A the series of semiconductor process operations 400 includes providing a semiconductor layer 206. For example, a wafer / die transport vehicle can be used to provide the semiconductor layer 206. In certain embodiments, the semiconductor layer 206 is provided on a temporary carrier or substrate (e.g., a ceramic carrier, a silicon substrate, or a gallium nitride (GaN) substrate, etc.).

[0084] As shown above, Figure 4BAs shown, semiconductor process operation series 400 includes forming a cavity 402 in semiconductor layer 206. In some embodiments, a pattern of a photoresist layer is used to etch semiconductor layer 206 to form cavity 402. In these embodiments, a photoresist layer can be formed on semiconductor layer 206 using a deposition tool. An exposure tool can be used to expose the photoresist layer to a radiation source to pattern the photoresist layer. A development tool can be used to develop and remove portions of the photoresist layer to expose the pattern. Based on the pattern, an etching tool can be used to etch semiconductor layer 206 to form cavity 402 in semiconductor layer 206. In some embodiments, the etching operation includes plasma etching, wet chemical etching, and / or other types of etching operations. In some embodiments, a photoresist removal tool can be used to remove remaining portions of the photoresist layer (e.g., using chemical strippers, plasma ashing, and / or other techniques). In some embodiments, a hard shielding layer is used as an alternative technique to pattern-based etching of semiconductor layer 206.

[0085] like Figure 4C As shown, semiconductor process operation series 400 includes forming a photodiode sensor structure 204 in cavity 402. The photodiode sensor structure 204 can be deposited in an epitaxial growth operation using deposition tools. Alternatively, the photodiode sensor structure 204 can be deposited in a physical vapor deposition operation, an atomic layer deposition operation, a chemical vapor deposition operation, an oxidation operation, and / or other suitable deposition operation using deposition tools.

[0086] like Figure 4D As shown, semiconductor process operation series 400 includes forming a portion of a semiconductor layer 206 over and / or on a photodiode sensor structure 204. Deposition tools can be used to deposit a portion of the semiconductor layer 206 during epitaxial growth operations. Alternatively, deposition tools can be used to deposit a portion of the semiconductor layer 206 during physical vapor deposition, atomic layer deposition, chemical vapor deposition, oxidation, and / or other suitable deposition operations.

[0087] like Figure 4E As shown, the semiconductor process operation series 400 includes forming a multilayer structure 210 over and / or on a semiconductor layer 206. Deposition tools can be used to deposit one or more layers of the multilayer structure 210 in physical vapor deposition, atomic layer deposition, chemical vapor deposition, electroplating, and / or other suitable deposition operations. In some embodiments, a planarization tool is used to planarize one or more layers of the multilayer structure 210 after deposition.

[0088] like Figure 4FAs shown, the series of semiconductor process operations includes forming isolation structures 208a and 208b in semiconductor layer 206. In some embodiments, to form isolation structures 208a and / or 208b, a photoresist layer is used to etch semiconductor layer 206 to form cavities serving as isolation structures 208a and / or 208b. In these embodiments, a photoresist layer can be formed on semiconductor layer 206 using a deposition tool. An exposure tool can be used to expose the photoresist layer to a radiation source to pattern the photoresist layer. A development tool can be used to develop and remove portions of the photoresist layer to expose the pattern. Based on the pattern, an etching tool can be used to etch semiconductor layer 206 to form cavities serving as isolation structures 208a and / or 208b. In some embodiments, the etching operation includes plasma etching, wet chemical etching, and / or other types of etching operations. In some embodiments, a photoresist removal tool can be used to remove the remaining portions of the photoresist layer (e.g., using chemical strippers, plasma ashing, and / or other techniques). In some embodiments, a hard shielding layer is used as another technique based on patterned etching of the semiconductor layer 206.

[0089] Furthermore, as part of the isolation structures 208a and 208b formed in the semiconductor layer 206, the isolation structures 208a and / or 208b can be deposited in the cavity using deposition tools in physical vapor deposition, atomic layer deposition, chemical vapor deposition, and / or other suitable deposition operations. In some embodiments, the isolation structures 208a and / or 208b can be planarized after deposition using planarization tools.

[0090] like Figure 4G As shown, the semiconductor process operation series 400 includes forming an optical spacer structure 212 over and / or on a multilayer structure 210. The optical spacer structure 212 can be deposited using a deposition tool in a spin-coating process. Alternatively, the optical spacer structure 212 can be deposited using a deposition tool in a physical vapor deposition operation, an atomic layer deposition operation, a chemical vapor deposition operation, and / or other suitable deposition operation. In some embodiments, a planarization tool is used to planarize the optical spacer structure 212 after deposition.

[0091] like Figure 4HAs shown, the series of semiconductor process operations 400 includes forming a lens structure 214 over and / or on the optical spacer structure 212. A spin-coating operation can be performed using a deposition tool to deposit material for the lens structure 214. Alternatively, a deposition tool can be used to deposit material for the lens structure in a physical vapor deposition operation, an atomic layer deposition operation, a chemical vapor deposition operation, and / or other suitable deposition operation. Furthermore, as part of forming the lens structure 214 over and / or on the optical spacer structure 212, a reflow tool can be used to heat the material, causing it to reflow and forming a convex surface 216.

[0092] like Figure 4I As shown, the series of semiconductor process operations includes forming an antireflective coating 218a over and / or on the lens structure 214. The antireflective coating 218a can be deposited using deposition tools in physical distillation operations, atomic layer deposition operations, chemical distillation operations, oxidation operations, and / or other suitable deposition operations.

[0093] like Figures 2A-2D , Figure 3 and Figures 4A-4I The series of semiconductor processing operations (e.g., semiconductor processing operation 400) for forming the pixel sensor structure (e.g., pixel sensor structure 200) includes forming a single-photon avalanche photodiode structure (e.g., photodiode sensor structure 204) in a semiconductor layer (e.g., semiconductor layer 206). This series of semiconductor processing operations includes forming an optical spacer structure (e.g., optical spacer structure 212) that transmits near-infrared light on the semiconductor layer. This series of semiconductor processing operations includes forming a lens structure (e.g., lens structure 214) that transmits near-infrared light on the optical spacer structure and on the single-photon avalanche photodiode structure.

[0094] As shown above, Figures 4A-4I This is for illustrative purposes only. Other embodiments may differ from those described above. Figures 4A-4I The descriptions differ.

[0095] Use and Figures 2A-2D , Figure 3 and Figures 4A-4I Related features can achieve one or more advantages to improve the performance of pixel sensor structures in low-light applications. For example, compared to another pixel sensor structure that does not include a lens structure with a protruding surface 216, a pixel sensor structure 200 including a lens structure 214 with a protruding surface 216 may redirect and increase the amount of light 306 received by the sensing area of ​​the photodiode sensor structure 204 to improve the quantum efficiency performance of the photodiode sensor structure 204 and / or the sensitivity performance of the pixel sensor structure 200.

[0096] Additionally, or compared to another pixel sensor structure that includes a photodiode sensor structure with a smaller width, the pixel sensor structure 200 including the photodiode sensor structure 204 with the increased width D2 can have an increased sensing area to receive more light 306 to improve quantum efficiency performance of the photodiode sensor structure 204 and / or sensitivity performance of the pixel sensor structure 200.

[0097] Additionally, or compared to another pixel sensor structure that includes a photodiode sensor structure with a smaller thickness, the photodiode sensor structure 204 in the pixel sensor structure 200 has an increased thickness D3, which can include more Group III-V material with a direct bandgap suitable for detecting individual photons to improve quantum efficiency performance of the photodiode sensor structure 204 and / or sensitivity performance of the pixel sensor structure 200.

[0098] Additionally, or compared to another pixel sensor structure that does not include an anti-reflective coating on the convex surface of the lens structure, the pixel sensor structure 200 including the anti-reflective coating 218a on the convex surface 216 of the lens structure 214 can reduce the amount of light (e.g., reflection 310a) reflected from the convex surface 216 and redirect that amount through the pixel sensor structure 200 to the photodiode sensor structure 204 to improve quantum efficiency performance of the photodiode sensor structure 204 and / or sensitivity performance of the pixel sensor structure 200.

[0099] Additionally, or compared to another pixel sensor structure that has a lens structure but does not include the light spacing structure 212, the light spacing structure 212 in the pixel sensor structure 200 with the lens structure 214 can position the lens structure 214 such that the amount of light 306 received by the lens structure 214 and redirected to the photodiode sensor structure 204 is increased. In other words, the light spacing structure 212 can reposition the focal length of the lens structure 214 to increase the amount of light 306 received by the photodiode sensor structure 204 to improve quantum efficiency performance of the photodiode sensor structure 204 and / or sensitivity performance of the pixel sensor structure 200.

[0100] Additionally, or compared to another pixel sensor structure that does not include an anti-reflective coating on the semiconductor layer, the pixel sensor structure 200 including the anti-reflective coating 218b on the semiconductor layer 206 can reduce the amount of light (e.g., reflection 310b) reflected from the semiconductor layer 206 and redirect that amount through the pixel sensor structure 200 to the photodiode sensor structure 204 to improve quantum efficiency performance of the photodiode sensor structure 204 and / or sensitivity performance of the pixel sensor structure 200.

[0101] Further, or compared to another pixel sensor structure that does not include an anti-reflective coating on the photodiode sensor structure, the pixel sensor structure 200 that includes the anti-reflective coating 218c on the photodiode sensor structure 204 can reduce the amount of light (e.g., reflection 310b) that is reflected from the photodiode sensor structure 204 and enable the photodiode sensor structure 204 to absorb the amount, to boost the quantum efficiency performance of the photodiode sensor structure 204 and / or the sensitivity performance of the pixel sensor structure 200.

[0102] In one or more aspects, the quantum efficiency performance of the photodiode sensor structure 204 and / or the sensitivity performance of the pixel sensor structure 200 is boosted to meet one or more performance thresholds related to low light sensing applications. By meeting the one or more performance thresholds, the amount of resources (e.g., labor, raw materials, semiconductor process tools, and / or computing resources consumed to achieve a production yield corresponding to the one or more performance thresholds) to support the sale of the pixel sensor structure 200 can be reduced.

[0103] Figure 5 is a flowchart of an exemplary process 500 related to forming a pixel sensor structure as described in the present disclosure. In some embodiments, Figure 5 one or more process blocks of Figures 4A-4I may be performed using one or more semiconductor process tools related to Figure 5 Additionally, or alternatively, one or more process blocks of may be performed using other elements or a set of elements that can be separate from or included in one or more semiconductor process tools, such as process tools that can be included in a semiconductor foundry, a chip fabrication facility, an image sensor fabrication facility, or a lens fabrication facility.

[0104] Figure 5 As shown in

[0105] As further shown in Figure 5 process 500 can include forming a light spacing structure that is transparent to near-infrared light on the semiconductor layer (block 520). For example, one or more semiconductor process tools can be used to form a light spacing structure (e.g., light spacing structure 212) on the semiconductor layer that is transparent to near-infrared light, as described in the present disclosure.

[0106] As shown in Figure 5It is further shown that process 500 can include forming a lens structure having light transmissivity for near-infrared light on the optical spacer structure and over the single photon avalanche photodiode structure (block 530). For example, one or more semiconductor processing tools can be used to form a lens structure (e.g., lens structure 214) having light transmissivity for near-infrared light and located on the optical spacer structure and over the single photon avalanche photodiode structure, as described herein.

[0107] Process 500 can include additional embodiments, such as any of the individual embodiments described below or any combination of embodiments related to one or more other processes described elsewhere herein.

[0108] In a first embodiment, process 500 includes forming an anti-reflective coating (e.g., anti-reflective coating 218c) in the cavity (e.g., cavity 402) of the semiconductor layer prior to forming the single photon avalanche photodiode structure. In certain embodiments, the cavity is used to form the single photon avalanche photodiode structure.

[0109] In a second embodiment, alone or in combination with the first embodiment, process 500 includes forming an anti-reflective coating (e.g., anti-reflective coating 218b) on the semiconductor layer prior to forming the optical spacer structure.

[0110] In a third embodiment, alone or in combination with one or more of the first and second embodiments, process 500 includes forming a multi-layer structure (e.g., multi-layer structure 210) on the anti-reflective coating prior to forming the optical spacer structure. In certain embodiments, forming the multi-layer structure includes depositing at least one layer of dielectric material having light transmissivity for near-infrared light on the anti-reflective coating.

[0111] In a fourth embodiment, alone or in combination with one or more of the first through third embodiments, forming the optical spacer structure includes depositing a layer of polymeric material on the semiconductor layer using a spin-on process.

[0112] In a fifth embodiment, alone or in combination with one or more of the first through fourth embodiments, forming the lens structure includes depositing a layer of polymeric material on the optical spacer structure using a spin-on process and reflowing the layer of polymeric material to form a surface having a convex curvature (e.g., convex surface 216) that extends outward from the lens structure.

[0113] In a sixth embodiment, alone or in combination with one or more of the first through fifth embodiments, process 500 includes forming an anti-reflective coating (e.g., anti-reflective coating 218a) on the surface having the convex curvature.

[0114] Although Figure 5Exemplary blocks of the flow 500 are shown, but in some embodiments, the flow 500 includes more blocks than those depicted, fewer blocks, different blocks, or arranged in a different order. Figure 5 Moreover, or alternatively, two or more of the blocks of the flow 500 can be performed in parallel.

[0115] Some embodiments of the present disclosure include a pixel sensor structure and a forming method. The pixel sensor structure includes a lens structure, a photodiode sensor structure, and a light spacer structure between the lens structure and the photodiode sensor structure. Compared to another pixel sensor structure including a photodiode sensor structure without the lens structure and the light spacer structure, the lens structure redirects near-infrared light through the light spacer structure to the photodiode sensor structure, which can improve quantum efficiency performance. In addition, different configurations of anti-reflective coatings can be included in the entire pixel sensor structure to further improve the quantum efficiency performance of the photodiode sensor structure.

[0116] As such, the quantum efficiency performance of the photodiode sensor structure and / or the sensitivity performance of the pixel sensor structure is improved to meet one or more performance thresholds related to applications of sensing images in low light environments. By meeting the one or more performance thresholds, the amount of resources (e.g., labor, raw materials, semiconductor process tools, and / or computing resources consumed to achieve a production yield corresponding to the one or more performance thresholds) supporting the use of the pixel sensor structure 200 is reduced.

[0117] As detailed above, some embodiments of the present disclosure provide a pixel sensor structure. The pixel sensor structure includes a photodiode region having a photodiode sensor structure in a semiconductor layer. The pixel sensor structure includes a lens structure separate from the photodiode region and having a convex surface facing away from the photodiode region. The pixel sensor structure includes a light spacing structure between the photodiode region and the lens structure. In some embodiments, the light spacing structure is configured to maintain a separation distance between a bottom of the lens structure and a top of the photodiode region. In an embodiment, the pixel sensor structure further includes a multi-layer structure between the semiconductor layer and the lens structure, wherein the light spacing structure is on the multi-layer structure. In an embodiment, the multi-layer structure includes at least one layer of electrically conductive material that is transparent to near-infrared light. In an embodiment, the pixel sensor structure further includes a first isolation structure and a second isolation structure on opposite sides of the photodiode sensor structure, wherein the light spacing structure is between the first and second isolation structures and the lens structure. In an embodiment, a ratio of a radius of curvature of the lens structure to a width of the photodiode sensor structure is included in a range of about 2:5 to about 3:5. In an embodiment, a thickness of the photodiode sensor structure is greater than or equal to about 3 microns. In an embodiment, one or more of the lens structure or the light spacing structure includes a high molecular material including: polymethyl methacrylate; polycarbonate; polyethylene; or polyvinylidene fluoride. In an embodiment, one or more of the lens structure or the light spacing structure includes a resin material including: an epoxy resin. In an embodiment, one or more of the lens structure or the light spacing structure includes an organic material including: a cyclic olefin copolymer; or a cyclic olefin polymer.

[0118] As detailed above, some embodiments of the present disclosure provide a system. The system includes an image sensor element including a pixel sensor structure. The pixel sensor structure includes a lens structure, a single photon avalanche photodiode structure, a multi-layer structure of electrically conductive material that is transparent to near-infrared light between the lens structure and the single photon avalanche photodiode structure, and at least one anti-reflective coating in a near-infrared light path between a near-infrared light source and the single photon avalanche photodiode structure. In an embodiment, the at least one anti-reflective coating includes: an anti-reflective coating on a substantially convex surface of the lens structure. In an embodiment, the single photon avalanche photodiode structure is embedded in a silicon layer, and the at least one anti-reflective coating includes: an anti-reflective coating on the silicon layer and between the multi-layer structure and the single photon avalanche photodiode structure. In an embodiment, the at least one anti-reflective coating includes: an anti-reflective coating on the single photon avalanche photodiode structure and between the multi-layer structure and the single photon avalanche photodiode structure.

[0119] As detailed above, some embodiments of the disclosure provide a method. The method includes forming a single photon avalanche photodiode structure in a semiconductor layer. The method includes forming a light spacer structure that is transparent to near infrared light on the semiconductor layer. The method includes forming a lens structure that is transparent to near infrared light on the light spacer structure and above the single photon avalanche photodiode structure. In an embodiment, the method further includes forming an anti-reflective coating in a cavity of the semiconductor layer before forming the single photon avalanche photodiode structure, wherein the cavity is used to form the single photon avalanche photodiode structure. In an embodiment, the method further includes forming an anti-reflective coating on the semiconductor layer before forming the light spacer structure. In an embodiment, the method further includes forming a multilayer structure on the anti-reflective coating before forming the light spacer structure, wherein forming the multilayer structure includes depositing at least one layer of dielectric material that is transparent to near infrared light on the anti-reflective coating. In an embodiment, forming the light spacer structure includes depositing a layer of polymer material on the semiconductor layer using a spin-on process. In an embodiment, forming the lens structure includes depositing a layer of polymer material on the light spacer structure using a spin-on process and reflowing the layer of polymer material to form a surface having a convex curvature extending away from the lens structure. In an embodiment, the method further includes forming an anti-reflective coating on the surface having the convex curvature.

[0120] As used herein, "satisfying a threshold" can refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like, depending on the context.

[0121] As used herein, the term "and / or," when used in the context of list items, is to be interpreted as specific options within the list being combined in a logical sense, e.g., within the context of a set of options, "and / or" refers to a full set of individual options and any and all combinations of the individual options. For example, "A and / or B" covers the cases of "A and B," "A and not B," and "B and not A."

[0122] The foregoing summary is not intended to define every implementation of the disclosure. The details offered above are merely samples of some of the applications of the principles of the disclosure. Further, it is understood that those of ordinary skill in the art will be able to devise other implementations and equivalents that are within the spirit and scope of the disclosure.

Claims

1. A pixel sensor structure, characterized in that, include: The photodiode region has a photodiode sensor structure in a semiconductor layer; The lens structure is separate from the photodiode region and has a protruding surface that is away from the photodiode region; as well as An optical spacer structure is located between the photodiode region and the lens structure. The optical spacer structure is configured to maintain the spacing between the bottom of the lens structure and the top of the photodiode region.

2. The pixel sensor structure according to claim 1, characterized in that, Also includes: A multilayer structure, between the semiconductor layer and the lens structure, The optical spacer structure is located on the multilayer structure.

3. The pixel sensor structure according to claim 2, characterized in that, The multilayer structure includes at least one layer of conductive material that is transparent to near-infrared light.

4. The pixel sensor structure according to claim 1, characterized in that, Also includes: The first isolation structure and the second isolation structure are located on opposite sides of the photodiode sensor structure. The optical spacer structure is located between the first isolation structure and the second isolation structure and the lens structure.

5. The pixel sensor structure according to claim 1, characterized in that, The ratio of the radius of curvature of the lens structure to the width of the photodiode sensor structure is included in the range of 2:5 to 3:

5.

6. The pixel sensor structure according to claim 1, characterized in that, The thickness of the photodiode sensor structure is greater than or equal to 3 micrometers.

7. A sensing system, characterized in that, include: Image sensor elements, including: Pixel sensor structure, including: Lens structure; Single-photon avalanche photodiode structure; A multilayer structure having a conductive material that transmits near-infrared light between the lens structure and the single-photon avalanche photodiode structure; and At least one anti-reflective coating is provided in the near-infrared optical path between the near-infrared light source and the single-photon avalanche photodiode structure.

8. The sensing system according to claim 7, characterized in that, The at least one anti-reflective coating comprises: An anti-reflective coating on the generally convex surface of the lens structure.

9. The sensing system according to claim 7, characterized in that, The single-photon avalanche photodiode structure is embedded in a silicon layer, and the at least one anti-reflective coating comprises: An anti-reflective coating is applied to the silicon layer and between the multilayer structure and the single-photon avalanche photodiode structure.

10. The sensing system according to claim 7, characterized in that, The at least one anti-reflective coating comprises: An anti-reflective coating is applied to the single-photon avalanche photodiode structure and between the multilayer structure and the single-photon avalanche photodiode structure.

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