Image sensor and electronic device

Abstract

To provide an image sensor and an electronic device in order to increase photosensitivity, improve utilization of light incident on the image sensor, and reduce crosstalk of a band tube.SOLUTION: The image sensor includes at least one photosensitive pixel, and each photosensitive pixel includes a plurality of nano-antenna layers 201. The plurality of nano-antenna layers are arranged in an overlapping manner. Each of the nano antenna layers may include at least one nano antenna 2011. The at least one nano-antenna generates resonance for incident light. Different nano-antenna layers generate resonances for different bands or different polarization directions of incident light. An output signal of the nano antenna layer may be used to obtain an image.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This application relates to the field of imaging, and more particularly to image sensors and electronic devices. [Background technology]

[0002] Color image sensors are widely used in consumer and security protection fields. Currently, there are two trends in technological development: one is the improvement of resolution, which means that pixel size is reduced when the light-sensitive area is limited; the other is the improvement of light-sensitive ability to meet the requirements of low-light photography.

[0003] Stacked image sensors implement stacked multicolor pixels based on the different penetration depths of different colored light in the photosensitive layer. Specifically, each pixel of the sensor is divided into three layers, blue, green, and red, from top to bottom. However, light may be absorbed to a certain extent during the transmission process, resulting in high crosstalk, especially crosstalk between long wavelength light and short wavelength light, for example, crosstalk between red and green light and blue light. Therefore, how to reduce crosstalk between light of each band has become an urgent issue to be solved. Summary of the Invention

[0004] Embodiments of the present application provide an image sensor and electronic devices to increase photosensitivity, improve utilization of light incident on the image sensor, and reduce crosstalk between incident light in each band.

[0005] In view of this, according to a first aspect, the present application provides an image sensor. The image sensor includes at least one photosensitive pixel. Each photosensitive pixel includes a plurality of nanoantenna layers. The plurality of nanoantenna layers are arranged to overlap each other. Each nanoantenna layer includes at least one nanoantenna. The at least one nanoantenna is configured to generate a resonance for incident light. Different nanoantenna layers are configured to generate a resonance for different incident light. Output signals from the nanoantennas are used to acquire an image. The different incident light includes light of different bands or light of different polarization directions, etc.

[0006] In the image sensor provided herein, a resonance is generated for incident light passing through a nanoantenna to obtain an electrical signal. Compared to providing multiple photosensitive layers, in the present application, a resonance is generated for incident light passing through the nanoantenna, which results in increased absorption of incident light and reduced crosstalk between incident light of each band. In addition, the thickness is smaller than that of a typical photosensitive layer. Therefore, in the present application, a smaller nanoantenna may be used to reduce the thickness of the antenna layer that absorbs all bands, compared to providing multiple photosensitive layers, thereby reducing crosstalk between light of each band and improving light utilization.

[0007] In a possible implementation, the image sensor further includes a plurality of pins. The plurality of pins are in contact with at least one photosensitive pixel and are configured to receive an electrical signal output by the at least one photosensitive pixel. The electrical signal is used to acquire an image. Therefore, in this implementation of the present application, the output signal of each photosensitive pixel may be transmitted through a pin to acquire the output of the image sensor.

[0008] In a possible implementation, the nanoantenna includes a material capable of generating a plasmon signal using light. The at least one nanoantenna is configured to generate a resonance for incident light to generate a plasmon signal. The plasmon signal is used to generate an electrical signal. Therefore, in this implementation of the present application, the resonance for the incident light may be implemented by referencing the plasmon effect of a relatively small nanoantenna and the incident light. Compared to directly disposing a photosensitive layer, the nanoantenna may absorb the incident light through resonance, thereby improving the utilization of the incident light and reducing crosstalk of the incident light in each band due to the nanoantenna absorbing more incident light.

[0009] In a possible implementation, there is a positive correlation between the thickness of each nanoantenna layer and the wavelength of the output signal generated by each nanoantenna layer. In this implementation of the present application, there is a positive correlation between the thickness of each antenna layer and the wavelength. Therefore, in practical application scenarios, the thickness of the corresponding antenna layer can be selected based on the wavelength that needs to be absorbed to adapt to various scenarios.

[0010] In a possible implementation, each nanoantenna layer further includes a photoelectric sensing structure, the photoelectric sensing structure being in contact with at least one surface of the at least one nanoantenna. The photoelectric sensing structure is configured to convert plasmon signals on the nanoantennas into electrical signals. Therefore, in this implementation of the present application, the photoelectric sensing structure may be disposed within the nanoantenna layer, such that the plasmon signals can be directly converted into electrical signals in each nanoantenna layer, and the electrical signals are output through pins.

[0011] Optionally, the photoelectric sensing structure may be in contact with one surface of the nanoantenna or may encase the nanoantenna.

[0012] In a possible implementation, a selective layer is further disposed between adjacent ones of the nanoantenna layers, the selective layer being configured to filter incident light transmitted between the adjacent nanoantenna layers.

[0013] Therefore, in this implementation of the present application, by providing a selective layer, crosstalk between incident light of different bands that is absorbed between the layers may be reduced, ultimately improving the quality of the obtained output image.

[0014] In a possible implementation, the selective layer is disposed on a first nanoantenna layer and a second nanoantenna layer. The first nanoantenna layer and the second nanoantenna layer are two adjacent layers of the plurality of nanoantenna layers. The transmission direction of the incident light is that the incident light is transmitted from the first nanoantenna layer to the second nanoantenna layer. The selective layer includes at least two materials having different refractive indices. The selective layer is configured to reflect light of a first band and transmit light of a second band. The first band is a band of resonated incident light in the first nanoantenna layer. The second band is a band of resonated incident light in the second nanoantenna layer.

[0015] Thus, in this implementation of the present application, to reduce the light transmission of bands of light absorbed by higher layers to lower layers, the selective layer may reflect light in bands absorbed by higher layers and transmit light in bands absorbed by lower layers, thereby reducing crosstalk between different bands of light absorbed by the layers.

[0016] In a possible implementation, each nanoantenna layer includes multiple nanoantenna sublayers, each nanoantenna sublayer including at least one nanoantenna, and the nanoantennas in the multiple nanoantenna sublayers generate resonances for incident light in the same band.

[0017] Therefore, in this implementation of the present application, multiple nanoantenna sublayers are disposed on each nanoantenna layer, and the plasmonic effect is enhanced through the coupling effect, thereby increasing the photosensitivity of the incident light and improving the absorption of the incident light.

[0018] In a possible implementation, in two adjacent nanoantenna layers of the plurality of nanoantenna layers, the thickness of the nanoantenna layer disposed above is not greater than the thickness of the nanoantenna layer disposed below.

[0019] Therefore, the thickness of the antenna layers is also arranged from thin to thick, so that light of short wavelengths may be absorbed first, crosstalk between incident light of all wavelengths may be avoided, and the absorption intensity of light in each band increases.

[0020] It should be understood that in this implementation of the present application, the incident direction of incident light can be understood as top to bottom, with bottom being the direction away from the incident light source and top being the direction closer to the incident light source.

[0021] In a possible implementation, the wavelength of the resonated incident light in the overlying nanoantenna layer (i.e., the wavelength for generating the resonance) is not greater than the wavelength of the incident light for which the nanoantennas in the underlying nanoantenna layer generate the resonance.

[0022] Therefore, in this embodiment of the present application, the nanoantennas may be arranged from top to bottom in order of decreasing absorption wavelength, i.e., decreasing wavelength of resonated incident light. Correspondingly, the thicknesses of the antenna layers may also be arranged in order of decreasing thickness. Therefore, light with a short wavelength may be absorbed first, and the wavelength of absorbed light may gradually increase, thereby avoiding crosstalk between incident light of all wavelengths and increasing the absorption intensity of light in each band.

[0023] In one possible implementation, the image sensor further includes a photoelectric sensing layer disposed below the plurality of nanoantenna layers, the photoelectric sensing layer configured to convert output signals generated by the plurality of nanoantenna layers into electrical signals.

[0024] Therefore, in this implementation of the present application, the photoelectric sensing layer may be separately disposed, so that the plasmon signal is converted into an electrical signal through the photoelectric sensing layer.

[0025] In a possible implementation, one end of the at least one nanoantenna included in each nanoantenna layer is connected to one end of a waveguide, and the other end of the waveguide is connected to the photoelectric sensing layer. The output signal generated by the at least one nanoantenna is transmitted to the photoelectric sensing layer through the waveguide. In this implementation of the present application, a specific implementation is provided in which the photoelectric sensing layer is separately disposed, so that the plasmon signal on the nanoantenna can be transmitted to the photoelectric sensing layer through the waveguide.

[0026] In a possible implementation, the vertical distance between nanoantennas included in two adjacent nanoantenna layers of the plurality of nanoantenna layers is not less than one-tenth of the wavelength of the resonated incident light in any one of the two adjacent nanoantenna layers. Thus, in this implementation of the present application, in order to avoid coupling effects caused by excessively close distances between nanoantennas included in layers, the vertical distance between nanoantennas included in an antenna layer is not less than one-tenth of the wavelength of the light absorbed by the two adjacent nanoantenna layers.

[0027] In a possible implementation, in two adjacent nanoantenna layers among the plurality of nanoantenna layers, the wavelength of incident light at which the nanoantenna in the upper nanoantenna layer produces a resonance is greater than the wavelength of incident light at which the nanoantenna in the lower nanoantenna layer produces a resonance.

[0028] In this implementation of the present application, when the photoelectric sensing layers are separately arranged, the wavelengths absorbed by the nanoantennas in the upper nanoantenna layer are greater than the wavelengths absorbed by the nanoantennas in the lower nanoantenna layer, thereby reducing losses during signal transmission through the waveguide and improving light utilization.

[0029] In a possible implementation, two adjacent nanoantenna layers may include antennas of the same shape, and the same-shaped antennas have different polarization directions. Therefore, in this implementation of the present application, antenna layers may be separately arranged for light of different polarizations but in the same band to absorb light of different polarizations and thereby improve light utilization.

[0030] In a possible implementation, if the antennas are dipole antennas, the dipole antennas in two adjacent nanoantenna layers have different extension directions; or if at least one nanoantenna is a spiral antenna, the spiral antennas in two adjacent nanoantenna layers have different rotation directions.

[0031] In this implementation of the present application, the nanoantenna may use multiple methods, and the antenna polarization directions of two adjacent layers of the nanoantenna are different, so that the coupling effect between the antennas in adjacent layers can be avoided, the absorption rate of light of different bands or different polarizations can be improved, and the utilization of light can be improved.

[0032] According to a second aspect, the present application provides an electronic device, the electronic device including the image sensor of the first aspect or any implementation of the first aspect. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a schematic diagram of a structure of an electronic device according to an embodiment of the present application;

[0034] [Figure 2] 1 is a schematic diagram of the structure of an image sensor according to an embodiment of the present application;

[0035] [Figure 3] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0036] [Figure 4] 1 is a schematic diagram of an antenna structure according to an embodiment of the present application;

[0037] [Figure 5] FIG. 10 is a schematic diagram of another antenna structure according to an embodiment of the present application;

[0038] [Figure 6] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0039] [Figure 7] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0040] [Figure 8] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0041] [Figure 9] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0042] [Figure 10] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0043] [Figure 11] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0044] [Figure 12] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application;

[0045] [Figure 13] FIG. 2 is a schematic diagram of another image sensor structure according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0046] The following describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. It is clear that the described embodiments are only a part, not all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0047] In the specification, claims, and accompanying drawings of this application, terms such as "first," "second," "third," and "fourth," etc. (when present) are intended to distinguish between similar objects, but do not necessarily indicate a particular order or sequence. Data termed in this manner are interchangeable under appropriate circumstances, and thus it should be understood that the embodiments described herein may be implemented in other orders than those illustrated or described herein. Additionally, the terms "comprise," "contain," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a list of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent in the process, method, product, or device.

[0048] In this description, "plurality" means two or more than two, unless specifically limited otherwise.

[0049] In this application, unless otherwise specified and limited, terms such as "attach," "connect," "connect," "fix," and "dispose" should be understood in a broad sense. For example, such terms may indicate a fixed connection, a detachable connection, or a built-in; may indicate a mechanical connection or an electrical connection; or may indicate a direct connection, an indirect connection through an intermediate medium, or an internal connection or an interactive relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific cases.

[0050] In the description of this application, orientations or positional relationships indicated by terms such as "length," "width," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "lower," "inside," or "outside" are those shown in the accompanying drawings, are intended merely to facilitate explanation and simplify the description of this application, and are not intended to indicate or imply that the devices or elements in question must have a particular orientation or be constructed and operated in a particular orientation. Accordingly, such terms should not be construed as limitations on this application.

[0051] Certain terms are used in this specification and claims to refer to specific components. Those skilled in the art should understand that the same component may be named differently by hardware manufacturers. In this specification and the following claims, components are distinguished from one another based on functional differences, not naming differences. The terms "including" and "comprises" referred to in this specification and claims are open terms and should be interpreted as "including but not limited to" or "comprises but not limited to."

[0052] First, for ease of understanding, some terms used in this application will be explained.

[0053] Plasmon effect: In solid systems with specific carrier concentrations (e.g., metals and semiconductors with specific carrier concentrations), fluctuations in carrier concentration at one location in space cause oscillations in carrier concentration at other locations due to Coulomb interactions between carriers. This elementary excitation characterized by oscillations in carrier concentration is called the plasmon effect.

[0054] The technical solutions of the present application will be described below with reference to the accompanying drawings.

[0055] The electronic device in the present embodiment may include a handheld device, an in-vehicle device, a wearable device, a computing device, or another processing device connected to a wireless modem. The electronic device may also include a digital camera, a cellular phone, a smartphone, a personal digital assistant (PDA) computer, a tablet computer, a laptop computer, a machine type communication (MTC) terminal, a point of sales (POS), an in-vehicle computer, a head-mounted device, a wearable device (e.g., a wristband or a smartwatch), a security device, a virtual reality (VR) device, an augmented reality (AR) device, and another electronic device with imaging capabilities.

[0056] Let's take a digital camera as an example. A digital camera, short for digital still camera, is a camera that converts optical images into digital signals using a photoelectric sensor. Unlike traditional cameras, which rely on changes in photosensitive chemicals on film to record images, digital camera sensors are photosensitive charge-coupled devices (CCDs) or complementary metal oxide semiconductors (CMOSs). Compared to traditional cameras, digital cameras have advantages such as convenience, faster speeds, repeatability, and more timeliness due to the direct use of photoelectric conversion image sensors. With the development of CMOS processing technology, digital cameras have become more powerful and have almost completely replaced traditional film cameras. Digital cameras are widely used in fields such as consumer electronics, security protection, human-machine interaction, computer vision, and self-driving.

[0057] 1 shows a schematic diagram of an electronic device according to the present application. As shown in the figure, the electronic device may include a lens group 110, an image sensor 120, and an electrical signal processor 130. The electrical signal processor 130 may include an analog-to-digital (A / D) converter 131 and a digital signal processor 132. The A / D converter 131 is an analog signal to digital signal converter and is configured to convert an analog electrical signal into a digital electrical signal.

[0058] 1 is not limited to the aforementioned components, and may further include more or fewer other components, such as a battery, a flash, a button, and a sensor, etc. In this embodiment of the present application, only an electronic device having an image sensor 120 mounted thereon is used as an example for explanation, but the elements mounted on the electronic device are not limited thereto.

[0059] Optical signals reflected by the photographed object are focused through the lens group 110 and captured on the image sensor 120. The image sensor 120 converts the optical signals into analog electrical signals. The analog electrical signals are converted into digital electrical signals through an analog-to-digital (A / D) converter 131 in the electrical signal processor 130, and the digital electrical signals are processed through the digital signal processor 132. For example, the data electrical signals are optimized through the operation of a series of complex numerical algorithms, and finally, an image is output. The electrical signal processor 130 may further include an analog signal pre-processor 133 configured to pre-process the analog electrical signals transmitted by the image sensor and output the pre-processed analog electrical signals to the analog-to-digital converter 131.

[0060] The performance of the image sensor 120 affects the quality of the final output image. The image sensor 120 may also be referred to as a photosensitive chip or photosensitive element, and includes hundreds of thousands to millions of photoelectric conversion elements. When illuminated with light, the image sensor 120 generates an electric charge and converts the electric charge into a digital signal through an analog-to-digital converter chip. The image sensor, i.e., the photosensitive elements including multiple pixels, implements imaging through photosensitive response.

[0061] For example, stacked image sensors implement stacked multicolor pixels based on the different penetration depths of different colored light in the photosensitive layer. Specifically, each pixel of the sensor is divided into three layers, blue, green, and red from top to bottom. However, some light may be absorbed during the transmission process, resulting in high crosstalk, especially the crosstalk of long wavelength light relative to the detection signal of short wavelength light. For example, crosstalk occurs due to the absorption of blue light by red and green light in the incident light.

[0062] Therefore, the present application provides an image sensor to reduce crosstalk between detection signals of different colors and enhance light absorption, so that the output data of the image sensor is more accurate. Even when the illumination is low, a clearer image can be obtained. The structure of the image sensor provided in the present application is described below.

[0063] The image sensor includes at least one photosensitive pixel. Each photosensitive pixel includes multiple nanoantenna layers. The multiple nanoantenna layers are arranged to overlap each other. Each nanoantenna layer includes at least one nanoantenna. The at least one nanoantenna is configured to generate a resonance for incident light. Nanoantennas included in a nanoantenna layer generate a resonance for incident light of the same band, and different nanoantenna layers generate a resonance for different incident light. The different incident light includes light of different bands or light of the same band but with different resonance directions. Output signals from the nanoantennas are used to acquire an image.

[0064] In this embodiment of the present application, a nanoantenna layer is provided, and the nanoantenna is formed by using a material that can generate a plasmonic effect, which results in a stronger focusing effect on the incident light. Therefore, by using a smaller-sized antenna layer, stronger absorption of the incident light can be achieved. Compared to disposing a separate photoelectric sensing layer, stronger absorption of the incident light can be achieved. In addition, the thickness of the photoelectric absorbing material is reduced, which results in reduced crosstalk between bands.

[0065] In a possible implementation, the image sensor further includes a plurality of pins. The plurality of pins are in contact with at least one photosensitive pixel and are configured to receive an electrical signal output by the at least one photosensitive pixel. The electrical signal is used to acquire an image. Therefore, in this implementation of the present application, the output signal of each photosensitive pixel may be transmitted through a pin to acquire the output of the image sensor.

[0066] In a possible implementation, the nanoantenna includes a material capable of generating a plasmon signal using light. At least one nanoantenna is configured to generate a resonance for the incident light to generate a plasmon signal. The plasmon signal is used to generate an electrical signal. Therefore, in this implementation of the present application, the resonance for the incident light may be implemented by referring to the plasmon effect of the small nanoantenna and the incident light. Compared to directly disposing a photosensitive layer, the nanoantenna may absorb the incident light through resonance, thereby improving the utilization of the incident light and reducing crosstalk of the incident light in each band due to the nanoantenna absorbing more incident light.

[0067] The image sensor provided herein will be described in detail below. For example, Figure 2 is a schematic diagram of an exemplary structure of an image sensor according to the present application.

[0068] The image sensor may include at least one photosensitive pixel 20 and a number of pins 21 .

[0069] 2 shows a plurality of photosensitive pixels. When there are multiple photosensitive pixels, the multiple photosensitive pixels are arranged in an array to form a photosensitive pixel array. A plurality of pins are in contact with the multiple photosensitive pixels. The multiple pins are configured to output electrical signals generated by the multiple photosensitive pixels. The electrical signals are used to capture an image.

[0070] 2, a plurality of photosensitive pixels are arranged in the form of a matrix array. A plurality of pins may be divided into row pins 211 and column pins 212. The row pins may be in contact with the top surface of each row of photosensitive pixels, and the column pins may be in contact with each column of photosensitive pixels. Specifically, each photosensitive pixel may be connected to a row pin or a column pin, so that an electrical signal generated by each photosensitive pixel can be output through the pin.

[0071] Specifically, as shown in FIG. 3, the photosensitive pixel includes multiple nanoantenna layers 201. The multiple nanoantenna layers 201 are arranged in an overlapping manner. Each nanoantenna layer may include at least one nanoantenna 2011 configured to generate a resonance for light of a specific wavelength or a specific polarization to generate a plasmon signal. Different nanoantenna layers may generate a resonance for different incident light. Different means that the band or resonance direction of the incident light is different. The plasmon signal is converted into an electrical signal, which is then output through a pin in contact with the photosensitive pixel.

[0072] It should be noted that in the following implementations of the present application, for example, each nanoantenna layer includes multiple nanoantennas, which may alternatively be replaced with at least one nanoantenna, and the details will not be described again below.

[0073] In this embodiment of the present application, a portion of the incident light that generates a resonance in the nanoantenna is absorbed by the nanoantenna, forming a plasmon signal on the surface. The plasmon signal can be converted into an electrical signal through the photoelectric sensing material and then output through the pin. Therefore, the thickness of the photoelectric absorbing material can be greatly reduced due to the strong focusing function of the nanoantenna, thereby reducing the absorption of crosstalk light. In addition, the wavelength selection function of the nanoantenna also reduces the absorption of crosstalk light, thereby achieving the effect of greatly reducing crosstalk. In addition, the strong focusing function of the nanoantenna enhances the light absorption function and improves photosensitivity, resulting in a clearer output image. Even under low illumination, a clearer image with higher brightness can be obtained.

[0074] Optionally, the nanoantenna may generally include a material having a surface plasmon effect, such as gold, silver, or graphene. Generally, different bands may correspond to different materials. For example, silver may be selected as the material of the nanoantenna for the visible light band, and graphene may be selected as the material of the nanoantenna for the far-infrared band, or multiple materials may be selected as the material of the nanoantenna for multiple bands. This may be specifically selected based on the actual application scenario, and this is not a limitation in the present application.

[0075] Optionally, there is a positive correlation between the thickness of the nanoantennas included in each nanoantenna layer and the wavelength of the plasmon signal or output signal generated by each layer of the nanoantenna. Specifically, a larger thickness of the nanoantenna indicates a larger wavelength of the plasmon signal generated by the nanoantenna, and a smaller thickness of the nanoantenna indicates a smaller wavelength of the plasmon signal generated by the nanoantenna. For example, as shown in FIG. 3, the thickness of the nanoantennas included in the multiple nanoantenna layers gradually increases from top to bottom, and the wavelength of the generated plasmon signal gradually increases accordingly.

[0076] Optionally, the nanoantennas included in each nanoantenna layer may have the same thickness, specifically, nanoantennas absorbing different bands may have the same thickness but may have different planar sizes or different planar shapes, etc. Also, for example, there may be a positive correlation between the size of the antenna and the wavelength absorbed by the antenna. Specifically, an appropriate shape or size may be selected based on an actual application scenario.

[0077] It should be noted that in this implementation of the present application, for ease of understanding, the incident direction of the incident light is understood to be from top to bottom, and the details will not be repeated later.

[0078] Optionally, the multiple nanoantenna layers in the image sensor may be arranged based on the wavelength of the resonated incident light in the nanoantenna layer. For example, from top to bottom, the nanoantenna layers may be arranged in order of increasing absorption wavelength (i.e., the wavelength of the resonated incident light). For example, the absorption wavelength of the nanoantenna arranged in the upper nanoantenna layer is greater than or equal to the absorption wavelength of the nanoantenna in the lower nanoantenna layer. In other words, the absorption wavelength of the nanoantenna arranged in the lower nanoantenna layer is less than or equal to the absorption wavelength of the nanoantenna in the upper nanoantenna layer. Indeed, the nanoantenna layers may alternatively be arranged in order of decreasing absorption wavelength. For example, the absorption wavelength of the nanoantenna layer arranged in the upper nanoantenna layer is less than or equal to the absorption wavelength of the nanoantenna in the lower nanoantenna layer.

[0079] Generally, there is a positive correlation between the thickness of the antenna layer and the absorption wavelength of the antenna, for example, if the absorption wavelength of the nanoantenna in the upper nanoantenna layer is greater than the absorption wavelength of the nanoantenna in the lower nanoantenna layer, the thickness of the upper nanoantenna layer will be greater than the thickness of the lower nanoantenna layer.

[0080] Generally, nanoantennas of different sizes and shapes may correspond to different resonant light wavelengths. When incident light is incident on a nanoantenna, a plasmon signal is generated on the surface of the nanoantenna due to the plasmon effect. Generally, the wavelength of the plasmon signal generated on the surface of the nanoantenna is smaller than the wavelength of the transmitted light. For example, the wavelength of the plasmon signal is generally 1 / 6 to 1 / 2 of the wavelength of light, depending specifically on the material used by the nanoantenna. The length of the nanoantenna is generally smaller than the wavelength of light and may be determined, for example, based on the wavelength of the plasmon signal on the surface of the nanoantenna. For example, there is a positive correlation between the wavelength of the plasmon signal on the surface of the nanoantenna and the length of the nanoantenna. For example, if the nanoantenna is a dipole antenna, the length of the dipole antenna may generally be 1 / 2 of the wavelength received by the dipole antenna. Therefore, the length of the dipole antenna may be 1 / 2 of the wavelength of the plasmon signal.

[0081] For example, the nanoantenna layer of a color image sensor may be divided into multiple structures arranged from top to bottom to absorb blue, green, and red light. The size and shape of the nanoantenna may be configured to enable the nanoantenna to implement an appropriate resonant response band. For example, the response bands of the nanoantenna may be 400 nm to 500 nm, 500 nm to 600 nm, and 600 nm to 700 nm from top to bottom, respectively, and the corresponding nanoantennas may be square-shaped gold nanoantennas with side lengths of 200 nm, 240 nm, and 280 nm, respectively.

[0082] In addition, the width of the antenna also affects the signal bandwidth to which the antenna responds. For example, there may be a positive correlation between the width of the antenna and the width of the wavelength bandwidth absorbed by the antenna. For example, a larger width of the nanoantenna indicates a wider bandwidth of incident light in which the nanoantenna generates resonance. Therefore, the width of the antenna may be adjusted based on the bandwidth to which the antenna needs to respond. For example, in some application scenarios, an antenna shape with a specific width, such as a tie shape, a square shape, or a circle shape, may be selected. Specifically, an appropriate antenna shape may be selected based on the actual application scenario.

[0083] In some scenarios, different nanoantenna layers may generate resonances for light of different bands or different polarizations, generating plasmon signals on the surface of the nanoantenna. For example, a first nanoantenna layer may generate resonances for light of band a with resonance direction A, and a second nanoantenna layer may generate resonances for light of band a with polarization direction B. Alternatively, the first nanoantenna layer may generate resonances for light of band a, and the second nanoantenna layer may generate resonances for light of band b. Thus, multiple nanoantenna layers may be arranged to increase the coverage of the frequency band received by the photosensitive pixel, allowing the image sensor to collect more information in certain scenarios and ultimately improving the quality of the output image.

[0084] In addition, nanoantennas have polarization resonance characteristics, allowing sensing of different polarizations to be implemented using different antenna layers. For example, the polarization direction of a dipole antenna is linearly polarized light that coincides with the antenna's extension direction, while the polarization direction of a spiral antenna is circularly polarized light that coincides with the antenna's rotation direction. Generally, when the polarization direction of incident light coincides with the polarization direction of the nanoantenna, the nanoantenna improves its absorption of the incident light. Therefore, in this implementation of the present application, different antenna layers may be arranged to absorb incident light of the same band but different polarization directions. For example, a nanoantenna with polarization direction A may be arranged on a higher layer, and a nanoantenna with polarization direction B may be arranged on a lower layer, thereby more effectively absorbing light of different polarizations. Generally, for light of the same band but different polarizations, the thickness of a lower nanoantenna layer is greater than the thickness of an upper nanoantenna layer. It can be understood that when light of the same band passes through an upper layer, some of the light is absorbed. To maintain the absorption balance of the two layers, the thickness of the lower nanoantenna layer may be increased, resulting in closer sensing intensities for nanoantenna layers absorbing incident light of the same band but different polarizations.

[0085] In addition, antenna layers that absorb light in the same band but with different polarization directions may generally be adjacent nanoantenna layers, resulting in a more uniform distribution of the nanoantenna layer thickness and closer absorption intensities for each nanoantenna layer.

[0086] For example, when the nanoantenna is a tie-shaped antenna, the polarization directions of the upper and lower nanoantennas are different, as shown in Figure 4. The polarization directions of the upper and lower antennas shown in Figure 4 are perpendicular to each other.

[0087] As another example, the nanoantenna may be a spiral antenna, with the upper and lower antennas having different rotation directions, as shown in Figure 5. For example, the upper antenna may use a clockwise rotation direction and the lower antenna may use a counterclockwise rotation direction.

[0088] Generally, the plasmon signal generated by the nanoantenna may be converted into an electrical signal through a photoelectric sensing material. The photoelectric sensing material may be added to the nanoantenna layer. Alternatively, the plasmon signal generated by the nanoantenna may be converted into an electrical signal through a photoelectric sensing layer including the photoelectric sensing material, and then output through the pin.

[0089] When a photoelectric sensing material is added to the nanoantenna layer, the photoelectric sensing material included in the nanoantenna layer directly converts the plasmon signal generated on the surface of the nanoantenna into an electrical signal, and the electrical signal is output through the pin. It can be understood that the nanoantenna is connected in the photoelectric sensing material, and the photosensitivity is enhanced through the nanoantenna, thereby reducing the thickness of the photoelectric sensing material and reducing crosstalk by improving the light selectivity. When the photoelectric sensing layer is separately disposed, the plasmon signal generated on the surface of the nanoantenna can be converted into an electrical signal through the photoelectric sensing layer and output through the pin.

[0090] Different photoelectric sensing materials may be used for different bands. For example, in the visible or near-infrared band, the photoelectric sensing material may be silicon, and in the mid-infrared or far-infrared band, the photoelectric sensing material may be InGaAs, etc. Specifically, the corresponding photoelectric sensing material may be selected based on the actual application scenario, which is not limited in the present application.

[0091] In the following, different arrangements of the photoelectric sensing material will be described separately.

[0092] 1. Adding photoelectric sensing material to the nanoantenna layer

[0093] A photoelectric sensing structure may be disposed on the nanoantenna layer. The photoelectric sensing structure includes a photoelectric sensing material for photoelectric conversion, which is used to convert a plasmon signal on the surface of the nanoantenna into an electrical signal. The photoelectric sensing structure is in contact with at least one surface of a nanoantenna in the nanoantenna layer. For example, the photoelectric sensing structure may be in contact with one surface of the nanoantenna, or the photoelectric sensing structure may encompass multiple nanoantennas.

[0094] Specifically, the structure of the photosensitive pixel may be shown in Figure 6. The photosensitive pixel may include n nanoantenna layers, and a photoelectric sensing material may be disposed on the nanoantenna layers to convert the plasmon signal generated by the nanoantenna into an electrical signal through photoelectric sensing.

[0095] For example, the structure of one of the nanoantenna layers may be shown in FIG. 7. The nanoantenna layer may include a nanoantenna 2011 and a photoelectric sensing structure 2012. The photoelectric sensing structure 2012 includes a photoelectric sensing material. The photoelectric sensing material encases the nanoantenna 2011. For example, a top view of one of the nanoantenna layers may be shown in FIG. 8. The nanoantennas may be arranged to form an array, and the photoelectric sensing material encases the nanoantennas, so that the plasmon signal can be completely converted into an electrical signal.

[0096] For example, another structure of the nanoantenna layer may be shown in FIG. 9 . The nanoantenna layer may include a nanoantenna 2011, a photoelectric sensing structure 2012, and a filling structure 2013. The nanoantenna 2011 is disposed on top of the photoelectric sensing structure 2012, and the bottom surface of the nanoantenna 2011 is in contact with the photoelectric sensing structure 2012. To fix the nanoantenna 2011, a filling structure 2013 may be disposed between the nanoantennas 2011, i.e., a filling medium is used to fill the gaps between the nanoantennas. The filling medium may be a transparent material medium to fix the nanoantenna and prevent movement of the nanoantenna in the nanoantenna layer. The photoelectric sensing structure is in contact with the nanoantenna to convert the plasmon signal generated on the surface of the nanoantenna into an electrical signal.

[0097] Generally, different wavelengths of light have different penetration depths for a particular photoelectric sensing material. For example, in silicon, the thickness of silicon required to absorb 95% of normally incident blue, green, and red light is approximately 1 micrometer, 3 micrometers, and 9 micrometers, respectively. However, due to the plasmon effect on the surface of the nanoantenna, the incident light can be strongly focused, significantly reducing the required thickness of the photoelectric sensing material. For example, after the nanoantenna is added, the thickness of silicon required to achieve 95% absorption of the above blue, green, and red light can be reduced to only 0.3 micrometers, 1 micrometer, and 3 micrometers. Therefore, the thickness of the silicon layer can be reduced, material consumption can be reduced, and the resulting nanoantenna layer becomes more flexible. In addition, for light that is not resonated by the nanoantenna in the current layer, unwanted absorption is also significantly reduced, reducing crosstalk, and the intensity of the crosstalk light can be reduced to one-third of its original intensity or even lower.

[0098] Additionally, because different wavelengths of light have different penetration depths, for most application scenarios the top nanoantenna layer is generally relatively thin, corresponding to relatively short wavelengths, although it is possible for the layers to have the same thickness for specific applications, e.g., to enhance absorption of short wavelength light.

[0099] Optionally, the nanoantenna layer may be divided into multiple nanoantenna sublayers to enhance the plasmonic effect on the nanoantenna surface and further reduce the required thickness of the photoelectric sensing material. Multiple nanoantenna sublayers resonate with the same incident light. Each nanoantenna sublayer may include multiple nanoantennas. When the distance between the sublayers is smaller than a certain range, e.g., smaller than 50 nm, the sublayers may interact with each other to form energy coupling and further enhance absorption.

[0100] For example, as shown in FIG. 10, each nanoantenna layer 2011 may include multiple nanoantenna sublayers. As shown in FIG. 8, the first nanoantenna layer may include nanoantenna sublayer 1 and nanoantenna sublayer 2, the second nanoantenna layer may include nanoantenna sublayer 3 and nanoantenna sublayer 4, and the third nanoantenna layer may include nanoantenna sublayer 5, nanoantenna sublayer 6, and nanoantenna sublayer 7. Additionally, in the structures of the second and third nanoantenna layers, nanoantenna sublayer 3 and nanoantenna sublayer 5 are in contact with the photoelectric sensing structure on the photoelectric sensing structure, respectively. It may be understood that the nanoantenna located inside the photoelectric sensing structure and the nanoantenna located on the photoelectric sensing material may be considered separately as nanoantenna sublayers.

[0101] In any implementation, a selective layer may be disposed between adjacent nanoantenna layers and configured to filter light transmitted between adjacent nanoantenna layers to filter out, to some extent, light of a particular wavelength transmitted to the next nanoantenna layer, thereby avoiding crosstalk caused to the reception of light by the next nanoantenna layer.

[0102] Two adjacent nanoantenna layers are used as an example. For ease of differentiation, the two adjacent nanoantenna layers are referred to as a first nanoantenna layer and a second nanoantenna layer. The first nanoantenna layer absorbs light in a first band. The second nanoantenna layer absorbs light in a second band. A selective layer may be disposed between the first nanoantenna layer and the second nanoantenna layer. Incident light passes through the first nanoantenna layer and is then transmitted to the second nanoantenna layer. The selective layer may reflect light in the first band and transmit light in the second band. If there is another nanoantenna layer below the second nanoantenna layer, the selective layer also transmits light in the band absorbed by the other nanoantenna layer below the second nanoantenna layer. It can be understood that in order to avoid crosstalk caused by bands corresponding to higher nanoantenna layers to lower nanoantenna layers and to improve the quality of the final output image, the selective layer may reflect light in bands absorbed by the nanoantenna layers above the selective layer and transmit light in bands absorbed by the nanoantenna layers below the selective layer.

[0103] Specifically, a selective layer disposed between two adjacent nanoantenna layers can be shown in FIG. 11 . A selective layer 202 is further disposed between two adjacent nanoantenna layers 201. The material of the selective layer can include at least two materials with different refractive indices, at least one of which has a transmission characteristic. For example, the selective layer can include a metal and another material with a different refractive index. Alternatively, the selective layer can include two media with different refractive indices, such as silicon dioxide and silicon nitride in the visible light band. Reflective and transmissive surfaces with frequency-selective functions are implemented through an array structure, resulting in a phase difference for incident light passing through materials with different refractive indices, allowing the selective layer to reflect light in a specific band range and transmit light in another band range. In addition, there can be one or more selective layers, which can be specifically adjusted based on the actual application scenario.

[0104] Two layers, e.g., the i-th nanoantenna layer and the (i+1)-th nanoantenna layer, are used as an example. A selective layer is further disposed between the i-th nanoantenna layer and the (i+1)-th nanoantenna layer. The selective layer may include three layers of nanoparticles. The nanostructured particles are silver nanoparticles. The support material may be P-SF68 glass. The spacing between particles in the first layer is 17 nanometers, and the diameter of the particles in the first layer is 13 nanometers. The spacing between particles in the second layer is 34 nanometers, and the diameter of the particles in the second layer is 26 nanometers. The spacing between particles in the third layer is 17 nanometers, and the diameter of the particles in the third layer is 13 nanometers. Simulation results show that this structure can reflect the 505 nm to 610 nm spectrum and transmit another band. The size of the silver nanoparticles is much smaller than the wavelength of the incident light and also much smaller than the size of the nanoantenna. Silver nanoparticles are primarily used for light selection.

[0105] Therefore, in this embodiment of the present application, the thickness of the photoelectric absorption material is greatly reduced due to the strong focusing function of the nanoantenna, thereby reducing the absorption of crosstalk light. Furthermore, the wavelength selection function of the nanoantenna also reduces the absorption of crosstalk light, thereby achieving the effect of greatly reducing crosstalk. In addition, due to the strong focusing function of the nanoantenna, the light absorption function is enhanced and the photosensitivity is improved. Ultimately, a clearer image with higher brightness can be obtained even under low illumination.

[0106] 2. Separately disposing the photoelectric sensing layer

[0107] A separately disposed photoelectric sensing layer may be shown in FIG. 12. The photoelectric sensing layer 203 may be disposed in the image sensor. The photoelectric sensing layer may be disposed below the plurality of nanoantenna layers. The photoelectric sensing layer may include a photoelectric sensing structure for photoelectric sensing and configured to convert a plasmon signal generated on the nanoantenna surface into an electrical signal.

[0108] In this implementation, in addition to the nanoantenna, the nanoantenna layer may be filled by using a transparent medium to improve the stability of the nanoantenna, so that incident light can be transmitted through the current layer to the next layer.

[0109] Specifically, the nanoantennas are connected to the photoelectric sensing layer through a waveguide, and as a result, plasmon signals are transmitted to the photoelectric sensing layer through the waveguide. One end of each of the nanoantennas included in each nanoantenna layer is connected to one end of a waveguide, and the other end of the waveguide is connected to the photoelectric sensing layer. The waveguide may pass through one or more nanoantenna layers. The plasmon signals generated by the nanoantennas are transmitted to the photoelectric sensing layer through the waveguide.

[0110] For example, the nanoantenna is a dipole antenna. As shown in FIG. 12, the inner ends of the two oscillators of the nanoantenna are respectively connected to one end of two segments of a waveguide, which may pass through one or more nanoantenna layers, and the other end of the waveguide is connected to the photoelectric sensing layer. Multiple photoelectric sensing units may be disposed on the photoelectric sensing layer. Each nanoantenna may correspond to one photoelectric sensing unit. The waveguide connected to each nanoantenna is connected to the photoelectric sensing unit corresponding to the nanoantenna and transmits the plasmon signal generated on the surface of the nanoantenna to the photoelectric sensing unit. The photoelectric sensing unit converts the plasmon signal into an electrical signal.

[0111] The material of the waveguide may be the same as that of the nanoantenna. Alternatively, a material different from that of the nanoantenna may be selected that can be used to transmit plasmonic signals. The material of the waveguide may be a semiconductor material with a wide bandgap, such as zinc oxide, to reduce optical absorption in the transmission process.

[0112] Generally, the transmission loss of relatively long wavelengths in a waveguide is relatively low. Therefore, nanoantennas having relatively long wavelengths are generally arranged in higher layers. That is, the nanoantenna layers may be arranged in order of increasing absorption wavelength. For example, the thickness of the upper nanoantenna layer is not greater than the thickness of the lower nanoantenna layer. In addition, the wavelengths corresponding to the nanoantennas in the upper nanoantenna layer are not greater than the wavelengths corresponding to the nanoantennas in the lower nanoantenna layer. Specifically, for example, the lengths of the waveguides connected to the nanoantennas corresponding to red, green, and blue may be 200 nm, 100 nm, and 50 nm, respectively.

[0113] In addition, to avoid coupling effects between nanoantennas, there is generally a specific spacing between nanoantennas in different layers. Optionally, the vertical distance between nanoantennas included in two adjacent nanoantenna layers of the multiple nanoantenna layers is not smaller than one-tenth of the wavelength of light absorbed by the two adjacent nanoantenna layers. That is, the spacing between nanoantennas in different layers is typically greater than at least one-tenth of the wavelength of light absorbed by the nanoantenna, i.e., the resonated incident light. For example, the spacing between nanoantennas in a layer may generally be set to at least 50 nm. To further reduce the height between nanoantenna layers, in the case of non-circular nanoantennas, nanoantennas of the same shape in adjacent layers may be offset at different angles to increase the spacing. As shown in FIG. 13, the nanoantennas in the upper layer and the nanoantennas in the lower layer may include cross-shaped nanoantennas. The nanoantennas in the lower layer are rotated 45 degrees with respect to the nanoantennas in the adjacent upper layer. The reduced height between layers may result in a shorter waveguide length and reduced propagation loss.

[0114] Regarding the image sensor provided above, the present application further provides a manufacturing method for the image sensor. Specifically, the method may include fabricating a nanoantenna layer layer by layer. When a photoelectric sensing material is disposed in each nanoantenna layer, a photoelectric sensing material is prepared in each nanoantenna layer when fabricating the nanoantenna layer layer by layer. When the photoelectric sensing layer is separately disposed, when fabricating the nanoantenna layer layer by layer, multiple nanoantennas, a filler medium, and a waveguide may be prepared in each nanoantenna layer. The waveguide extends through the nanoantenna and is connected to it. The waveguide extends through multiple layers and is connected to the photoelectric sensing layer. Furthermore, the photoelectric sensing layer is prepared using a photoelectric sensing material. A photoelectric sensing unit is prepared in each photoelectric sensing layer. The photoelectric sensing unit is connected to the waveguide. After fabrication, the photosensitive pixels are arranged in an array. Row pins and column pins are separately arranged for the array.

[0115] The above description is only an optional embodiment of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An image sensor comprising at least one photosensitive pixel, Each photosensitive pixel has a plurality of nanoantenna layers, the plurality of nanoantenna layers are arranged in an overlapping manner, each nanoantenna layer includes at least one nanoantenna, the at least one nanoantenna is configured to generate a resonance for incident light, the nanoantennas in different nanoantenna layers are configured to generate a resonance for different incident light, and output signals of the nanoantennas are used to acquire an image. Image sensor.

2. 2. The image sensor of claim 1, wherein the image sensor further comprises a plurality of pins, the plurality of pins being in contact with the at least one photosensitive pixel, the plurality of pins being configured to receive an electrical signal output by the at least one photosensitive pixel, the electrical signal being used to capture an image.

3. 3. The image sensor of claim 1, wherein the at least one nanoantenna configured to create a resonance for incident light comprises: the at least one nanoantenna configured to create a resonance for the incident light to generate a plasmon signal, the plasmon signal being used to generate an electrical signal.

4. 4. The image sensor of claim 1, wherein each nanoantenna layer further comprises a photoelectric sensing structure, the photoelectric sensing structure being in contact with at least one surface of the at least one nanoantenna, and the photoelectric sensing structure being configured to convert the output signal of the at least one nanoantenna into an electrical signal.

5. 5. The image sensor of claim 4, further comprising a selective layer disposed between adjacent ones of the plurality of nanoantenna layers, the selective layer configured to filter light transmitted between the adjacent nanoantenna layers.

6. 6. The image sensor of claim 5, wherein the selective layer is disposed on a first nanoantenna layer and a second nanoantenna layer, the first nanoantenna layer and the second nanoantenna layer being two adjacent layers of the plurality of nanoantenna layers; the transmission direction of the incident light is that the incident light passes through the first nanoantenna layer and is transmitted to the second nanoantenna layer; the selective layer includes at least two materials having different refractive indices; the selective layer is configured to reflect light of a first band and transmit light of a second band, the first band being a band of resonated incident light in the first nanoantenna layer, and the second band being a band of resonated incident light in the second nanoantenna layer.

7. 7. The image sensor of claim 4, wherein each nanoantenna layer has multiple nanoantenna sublayers, each nanoantenna sublayer including at least one nanoantenna, and the multiple nanoantenna sublayers generate resonances for incident light in the same band.

8. 8. The image sensor of claim 1, wherein in two adjacent nanoantenna layers of the plurality of nanoantenna layers, a thickness of the nanoantenna layer disposed above is less than or equal to a thickness of the nanoantenna layer disposed below.

9. 9. The image sensor of claim 1, wherein the wavelength of resonated incident light in the upper nanoantenna layer is less than or equal to the wavelength of resonated incident light in the lower nanoantenna layer.

10. 8. The image sensor of claim 1, wherein, in two adjacent nanoantenna layers among the plurality of nanoantenna layers, the wavelength of incident light at which the nanoantenna in the upper nanoantenna layer produces resonance is greater than the wavelength of incident light at which the nanoantenna in the lower nanoantenna layer produces resonance.

11. The image sensor of claim 1 , wherein there is a positive correlation between the thickness of the nanoantenna included in each nanoantenna layer and the wavelength of the output signal of each nanoantenna layer.

12. 12. The image sensor of claim 1, wherein antennas of the same shape and included in two adjacent nanoantenna layers have different polarization directions.

13. When the at least one nanoantenna is a dipole antenna, the dipole antennas in two adjacent nanoantenna layers have different extension directions; or When the at least one nanoantenna is a spiral antenna, the spiral antennas in two adjacent nanoantenna layers have different rotation directions. The image sensor of claim 12.

14. An electronic device, said electronic device comprising an image sensor according to any one of claims 1 to 13.

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