Pixel structure and infrared detector

Abstract

The utility model provides a pixel structure and an infrared detector, relates to the technical field of infrared detectors, and aims to improve the infrared absorption capability of the detector. The pixel structure comprises bridge arms, bridge piers and a bridge floor. The bridge floor is connected with the piers through the bridge arms. The bridge surface comprises an infrared absorption layer and an enhanced absorption layer above the infrared absorption layer, the enhanced absorption layer comprises a metasurface structure and a conductive structure, the conductive structure is connected with the bridge arms, and the conductive structure is further connected with the infrared absorption layer. According to the pixel structure, the enhanced absorption layer composed of the metasurface structure and the conductive structure is added on the infrared absorption layer, so that the infrared absorption efficiency of the pixel structure can be enhanced. Resonance absorption of infrared radiation of a specific wave band can be achieved by regulating and controlling the surface plasmon effect, and the responsiveness of the pixel structure to an infrared spectrum is remarkably improved. And the preparation of the enhanced absorption layer is highly compatible with the preparation process of the existing pixel, only the pattern of the single-layer mask plate needs to be adjusted, no additional process needs to be added, and the practicability and the mass production potential are improved.

Description

Technical Field

[0001] This utility model relates to the field of infrared detector technology, specifically to a pixel structure and an infrared detector. Background Technology

[0002] An infrared detector is a device that can detect infrared radiation and convert it into an electrical signal. It is widely used in various fields, such as thermal imaging, remote sensing, and infrared communication.

[0003] A pixel is an important component of an infrared detector; a pixel typically refers to an individual detector within an infrared detector array. Each pixel is responsible for detecting infrared radiation in a specific area and converting it into an electrical signal.

[0004] Improving the absorption capacity of infrared detectors is of great significance to enhancing their performance. However, existing methods for improving the absorption capacity of infrared detectors usually require complex manufacturing processes, making mass production difficult. Utility Model Content

[0005] This utility model provides a pixel structure and an infrared detector, which aims to improve the infrared absorption capability of the detector.

[0006] To achieve the above objectives, the embodiments of this utility model adopt the following technical solutions:

[0007] In a first aspect, this application provides a pixel structure, which includes a bridge arm, a bridge pier, and a bridge deck. The bridge deck is connected to the bridge pier via the bridge arm. The bridge deck includes an infrared absorbing layer and an enhanced absorption layer disposed above the infrared absorbing layer. The enhanced absorption layer includes a metasurface structure and a conductive structure. The conductive structure is connected to the bridge arm and also to the infrared absorbing layer.

[0008] The pixel structure provided in this application adds an enhanced absorption layer composed of metasurface and conductive structures to the infrared absorption layer, which can enhance the infrared absorption efficiency of the pixel structure. By modulating the surface plasmon resonance effect, resonant absorption of infrared radiation in a specific band can be achieved, significantly improving the pixel structure's response to infrared spectra. Furthermore, the fabrication of the enhanced absorption layer is highly compatible with existing pixel fabrication processes, requiring only adjustment of the pattern of a single-layer mask without adding additional processes or materials, thus improving the practicality and mass production potential of the design.

[0009] In one possible implementation, the bridge arm includes a first bridge arm and a second bridge arm, and the pier includes a first pier and a second pier. The first bridge arm is connected to the first pier, and the second bridge arm is connected to the second pier. The conductive structure includes a first conductive structure and a second conductive structure. One end of the infrared absorbing layer is connected to the first bridge arm through the first conductive structure, and the other end of the infrared absorbing layer is connected to the second bridge arm through the second conductive structure. The metasurface structure is located between the first conductive structure and the second conductive structure.

[0010] As one possible implementation, the bridge deck also includes a first dielectric layer disposed between the infrared absorbing layer and the metasurface structure. The infrared absorbing layer includes a main body and a first sub-body and a second sub-body located on both sides of the main body, respectively. The main body overlaps with the first dielectric layer, the first sub-body overlaps with and is connected to the first conductive structure, and the second sub-body overlaps with and is connected to the second conductive structure.

[0011] As one possible implementation, the bridge deck also includes a bridge deck support layer located on the side of the infrared absorbing layer away from the first dielectric layer. One end of the bridge deck support layer is located between the side of the infrared absorbing layer and the first bridge arm, and is connected to the first conductive structure. The other end of the bridge deck support layer is located between the side of the infrared absorbing layer and the second bridge arm, and is connected to the second conductive structure.

[0012] As one possible approach, conductive structures and metasurface structures are formed in the same thin film deposition process.

[0013] As one possible approach, the conductive structure and the metasurface structure are made of the same material.

[0014] As one possible implementation, the conductive structure and the metasurface structure have the same thickness.

[0015] As one possible implementation, the thickness of the metasurface structure is less than or equal to 5000 angstroms.

[0016] In one possible implementation, the bridge arm includes a bridge arm support layer and a bridge arm conductive layer. The bridge arm support layer surrounds the bridge arm conductive layer, and the bridge arm conductive layer is connected to a conductive structure.

[0017] As one possible implementation, the bridge deck also includes support columns and umbrella-shaped canopies. The support columns are located on the side of the metasurface structure away from the infrared absorption layer, and the umbrella-shaped canopies are located on the side of the support columns away from the infrared absorption layer and are connected to the support columns. The metasurface structure includes at least one metastructure, and the projection of the support columns onto the infrared absorption layer lies within the projection of a metastructure onto the infrared absorption layer.

[0018] As one possible implementation, the metasurface structure includes a first element and multiple second elements arranged around the first element. The projection of the support pillar onto the infrared absorption layer lies within the projection of the first element onto the infrared absorption layer.

[0019] Secondly, this application also provides an infrared detector. The infrared detector includes a readout circuit and a pixel structure as mentioned in the first aspect and its possible implementations. The pixel structure is connected to the imaging readout circuit. The beneficial effects of the second aspect and its specific implementations can be referred to in conjunction with the beneficial effects of the first aspect, and will not be repeated here. Attached Figure Description

[0020] Figure 1 A schematic diagram of a pixel structure provided in an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the composition of a pixel structure provided in an embodiment of this application;

[0022] Figure 3 A schematic diagram of another pixel structure provided in an embodiment of this application;

[0023] Figure 4 A schematic diagram of an infrared detector provided for an embodiment of this application;

[0024] Figure 5 This is a comparative schematic diagram of an infrared detector provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "linked" in this utility model have the meaning of establishing conductivity. The specific meaning needs to be understood in conjunction with the context.

[0028] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0029] An infrared detector is a sensor used to detect the infrared radiation energy of external target objects. It can convert the detected infrared radiation into an electrical signal. Due to its non-contact measurement, remote detection capability, and strong anti-interference ability, infrared detectors are widely used in various fields, such as thermal imaging, remote sensing, and infrared communication.

[0030] The focal plane array (FPA) of an infrared detector is used to receive and convert infrared radiation into electrical signals, and it is composed of an array of multiple pixels. Each pixel corresponds to a specific field of view, so the pixel is an indispensable core component of an infrared detector. Improving the pixel's ability to absorb and convert infrared radiation means improving the performance of the infrared detector.

[0031] This application provides a pixel structure, which is exemplary and combined with Figure 1 and Figure 2 The pixel structure includes a bridge arm 1, a bridge pier 2, and a bridge deck 3. The bridge deck 3 is connected to the bridge pier 2 via the bridge arm 1. The bridge deck 3 includes an infrared absorption layer 31 and an enhanced absorption layer 32 disposed above the infrared absorption layer 31. The enhanced absorption layer 32 includes a metasurface structure 321 and a conductive structure 322. The conductive structure 322 is connected to the bridge arm 1 and is also connected to the infrared absorption layer 31.

[0032] As one possible implementation, the infrared absorption layer 31 is a thermistor layer, which is the main source for the conversion of infrared radiation into electrical signals in the pixel structure. The bridge arm 1 can also absorb some infrared radiation. The more crucial function of the bridge arm 1 is to act as an electrical connection, transmitting the electrical signals converted from the bridge deck 3 to the bridge pier 2.

[0033] The enhanced absorption layer 32 in the pixel structure provided in this embodiment is the core for improving infrared absorption efficiency, and a metasurface structure 321 is disposed on the enhanced absorption layer 32. The metasurface structure 321 is a periodically arranged micro / nano structure, and the metasurface structure 321 is made of metallic material. When infrared light is incident on the metasurface structure 321, the infrared light interacts with the free electrons in the metasurface structure 321, exciting surface plasmon resonance. This resonance will generate a strong enhancement of the local electromagnetic field near the metasurface structure 321, enabling the efficient absorption and scattering of infrared light of a specific wavelength.

[0034] Because the geometry, size, and arrangement period of the metasurface structure 321 can be precisely controlled, the metasurface structure 321 can be designed specifically for the required infrared wavelength band according to actual needs. For example, by adjusting the linewidth, period, and thickness of the metastructure 320 in the metasurface structure 321, the absorption rate of a specific infrared band can be optimized, thereby achieving spectral control.

[0035] Furthermore, after infrared light is absorbed by the metasurface structure 321, the locally generated heat is concentrated and transferred to the infrared absorption layer 31. This heat concentration effect can improve the response efficiency of the infrared absorption layer 31, thereby enhancing the performance of the detector.

[0036] The enhanced absorption layer 32 also includes a conductive structure 322. Since the conductive structure 322 is connected to both the infrared absorption layer 31 and the bridge arm 1, it can transmit the electrical signal generated by the infrared absorption layer 31. Through its cooperation with the conductive structure 322, the metasurface structure 321 establishes a highly efficient energy conduction channel, enabling the infrared energy absorbed by the pixel structure to be rapidly converted into an electrical signal, further enhancing the response sensitivity of the pixel structure.

[0037] As one possible implementation, the metasurface structure 321 and conductive structure 322 provided in this application embodiment are formed in the same thin film deposition process. This means that in this application embodiment, the enhanced absorption layer 32 only involves the modification of the single-layer mask pattern, and has no impact on the original preparation process. It does not require the introduction of new steps in the original thin film deposition process. The preparation is simple, the cost is low, and it has the value of mass production.

[0038] Therefore, adding an enhanced absorption layer 32, composed of a metasurface structure 321 and a conductive structure 322, to the infrared absorption layer 31 can enhance the infrared absorption efficiency of the pixel structure. By modulating the surface plasmon resonance effect, resonant absorption of infrared radiation in a specific wavelength band can be achieved, significantly improving the pixel structure's response to infrared spectra. Furthermore, the fabrication of the enhanced absorption layer is highly compatible with existing pixel fabrication processes, requiring only adjustment of the pattern of a single-layer mask without adding additional processes or materials, thus improving the practicality of the design and its mass production potential.

[0039] As one possible implementation, such as Figure 1 and Figure 2 As shown, bridge arm 1 includes a first bridge arm 11 and a second bridge arm 12, and bridge pier 2 includes a first bridge pier 21 and a second bridge pier 22. The first bridge arm 11 is connected to the first bridge pier 21, and the second bridge arm 12 is connected to the second bridge pier 22. The conductive structure 322 includes a first conductive structure 3221 and a second conductive structure 3222. One end of the infrared absorption layer 31 is connected to the first bridge arm 11 through the first conductive structure 3221, and the other end of the infrared absorption layer 31 is connected to the second bridge arm 12 through the second conductive structure 3222. The metasurface structure 321 is located between the first conductive structure 3221 and the second conductive structure 3222.

[0040] Bridge arm 1 is divided into first bridge arm 11 and second bridge arm 12, and pier 2 is divided into first pier 21 and second pier 22. These are connected to form stable mechanical support and electrical connection paths, preventing structural deformation and improving the mechanical strength and durability of the pixel structure. The conductive structure 322 is further subdivided into first conductive structure 3221 and second conductive structure 3222, which are connected to both ends of the infrared absorption layer 31, ensuring the integrity of electrical signal transmission. This allows for reliable transmission of the electrical signals generated by infrared absorption, reducing energy loss and electrical noise, and improving the performance of the pixel structure. The placement of the metasurface structure 321 between the first conductive structure 3221 and the second conductive structure 3222 avoids the conductive structure 322 from blocking the infrared absorption area, helping to optimize the effective area of ​​infrared absorption and improve the infrared absorption efficiency of the pixel structure. Furthermore, this layout provides more flexible manipulation space for designing metasurface structures 321 of different sizes and periods.

[0041] As one possible implementation method, refer to Figure 2The bridge deck also includes a first dielectric layer 33, which is disposed between the infrared absorption layer 31 and the metasurface structure 32. The infrared absorption layer 31 includes a main body 311 and a first sub-part 312 and a second sub-part 313 located on both sides of the main body 311. The main body 311 overlaps with the first dielectric layer 33, the first sub-part 312 overlaps with and is connected to the first conductive structure 3221, and the second sub-part 313 overlaps with and is connected to the second conductive structure 3222.

[0042] The first dielectric layer 33 optimizes the transmission path of infrared light in the infrared absorption layer 31. As a buffer layer, it effectively improves the optical matching between the infrared absorption layer 31 and the metasurface structure 321, reduces optical loss, and further enhances the absorption efficiency in specific wavelength bands. The partitioned design of the infrared absorption layer 31 ensures that the main body 311 is concentrated on absorbing infrared radiation, while the first sub-part 312 and the second sub-part 313 are used for electrical connection. This avoids the problem of weakening absorption efficiency due to electrical connection, thereby improving the stability of electrical signal transmission and the response speed of the pixel structure.

[0043] As one possible implementation method, refer to Figure 2 The bridge deck also includes a bridge deck support layer 34, which is located on the side of the infrared absorption layer 3 away from the first dielectric layer 33. One end of the bridge deck support layer 34 is located between the side of the infrared absorption layer 31 and the first bridge arm 11, and is connected to the first conductive structure 3221. The other end of the bridge deck support layer 34 is located between the side of the infrared absorption layer 31 and the second bridge arm 12, and is connected to the second conductive structure 3222.

[0044] The bridge deck support layer 34 reduces the stress on the infrared absorption layer 31 caused by thermal expansion and contraction, improving the thermal stability of the pixel structure, especially in environments with high temperatures or drastic temperature changes. The bridge deck support layer 34 is connected to the conductive structure 322, further stabilizing the electrical connection between the infrared absorption layer 31 and the bridge arm 1, and reducing the risk of electrical connection failure due to mechanical stress or prolonged use.

[0045] As one possible implementation, since the metasurface structure 321 and the conductive structure 322 provided in this embodiment are formed in the same thin film deposition process, the conductive structure 322 and the metasurface structure 321 are made of the same material. Using the same material reduces the complexity caused by switching between different materials during manufacturing, such as avoiding multiple coating or patterning processes, thus improving production efficiency and process consistency. It also reduces interface problems between different materials, such as interface stress caused by differences in the thermal expansion coefficients of different materials, thereby improving the success rate and yield of fabrication.

[0046] As one possible implementation, since the metasurface structure 321 and the conductive structure 322 provided in this application embodiment are formed in the same thin film deposition process, the conductive structure and the metasurface structure have the same thickness. The thickness of the metasurface structure is less than or equal to 5000 angstroms. Generally, the thickness of the conductive structure and the metasurface structure is between 100 angstroms and 500 angstroms.

[0047] In some embodiments, refer to Figure 1 The bridge arm 1 includes a bridge arm conductive layer 13 and a bridge arm support layer 14. The bridge arm support layer 14 surrounds the bridge arm conductive layer 13, and the bridge arm conductive layer 13 is connected to the conductive structure.

[0048] As one possible implementation, for example, such as Figure 3 As shown, the bridge deck 3 also includes support columns 35 and umbrella-shaped structures 36. The support columns 35 are located on the side of the metasurface structure 321 away from the infrared absorption layer 31, and the umbrella-shaped structures 36 are located on the side of the support columns 35 away from the infrared absorption layer 31 and are connected to the support columns 35. The metasurface structure 321 includes at least one substructure 310, and the projection of the support columns 35 onto the infrared absorption layer 31 lies within the projection of one of the substructures 310 onto the infrared absorption layer 31.

[0049] As one possible implementation, a second dielectric layer is provided on the side of the metasurface structure 321 away from the infrared absorption layer 31, the metasurface structure 321 is connected to the second dielectric layer, and the umbrella surface 36 is connected to the second dielectric layer through the support column 35.

[0050] The arrangement of the umbrella surface 36 increases the reflection and transmission path of infrared radiation, helping to enhance the absorption efficiency of infrared radiation and further improve the absorption capability for specific wavelengths. The projection of the support column 35 is confined within the element structure 310, avoiding optical interference and ensuring effective absorption of infrared radiation. The support column 35 provides stable support for the umbrella surface 36, reducing deformation problems caused by the large area coverage of the umbrella surface 36, thereby improving the overall mechanical strength and vibration resistance of the element structure.

[0051] As one possible implementation method, refer to Figure 3 The metasurface structure includes a first element structure 3101 and multiple second elements structure 3102, with the multiple second elements structure 3102 arranged around the first element structure 3101. The projection of the support pillar 35 onto the infrared absorption layer 31 lies within the projection of the first element structure 3101 onto the infrared absorption layer 31.

[0052] Multiple second-element structures 3102 are arranged around a first-element structure 3101 in a center-periphery layout. The first-element structure 3101 is located at the center and is typically larger in size. The combination of the central first-element structure 3101 and the support pillar 35 forms localized surface plasmons, generating a strong local electromagnetic field enhancement effect, thus capturing and converging the energy of incident infrared light. Multiple second-element structures 3102 are arranged around the first-element structure 3101 in a periodic array. For example, the size of the first-element structure 310 is between 0.2 μm and 5 μm, and the arrangement period of the second-element structures 3102 is between 0.2 μm and 3 μm. The peripheral second-element structures 3102, through the coupling effect of surface plasmons, allow light energy to propagate between the center and the periphery. This optical resonant coupling can expand the light absorption range, increase the absorption bandwidth, and simultaneously modulate the reflection and scattering of infrared light, thereby optimizing the mid-absorption performance of the pixel structure and achieving higher infrared absorption efficiency.

[0053] This application also provides an infrared detector, exemplarily, such as... Figure 4 As shown, the infrared detector 100 includes a readout circuit 50 and a pixel structure 60 as described above. The pixel structure 60 is connected to the imaging readout circuit 50. The readout integrated circuit (ROIC) is a key component in an infrared focal plane array (FPA), and its main function is to read electrical signals from each pixel in the focal plane array and convert them into digital signals for further processing and display. Because the infrared absorption layer and the enhanced absorption layer in the pixel structure 60 of the infrared detector 100 provided in this application work synergistically, surface plasmon resonance can be enhanced, significantly improving the absorption efficiency of infrared light.

[0054] For example, such as Figure 5 As shown, Figure 5 The image shows a comparison of the infrared absorption rates between an infrared detector using the pixel structure provided in this application and a conventional infrared detector. The infrared absorption rate of the infrared detector using the pixel structure provided in this application is also the infrared absorption rate after the metasurface structure enhances absorption, while the infrared absorption rate of the conventional infrared detector is also the infrared absorption rate before the metasurface structure enhances absorption. Figure 5 The horizontal axis in the graph represents the infrared band. Figure 5 The vertical axis represents the absorption rate. According to... Figure 5 It can be seen that from 8μm to 14μm, the infrared absorption rate of the infrared detector using the pixel structure provided in this application is always greater than that of the conventional infrared detector in most infrared bands, except in the 12μm infrared band, where the infrared absorption rates of the two are the same.

[0055] It should be noted that the shape, thickness, size, and arrangement period of the metasurface structure will affect the absorption capacity of different infrared bands. In actual production, it should be prepared according to the requirements.

[0056] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0057] Finally, it should be noted that the above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A picture element structure, characterized by The bridge arm, the bridge pier and the bridge deck; The bridge deck is connected with the bridge pier through the bridge arm; The bridge deck comprises an infrared absorption layer and an enhanced absorption layer arranged above the infrared absorption layer, the enhanced absorption layer comprises a metasurface structure and a conductive structure, the conductive structure is connected with the bridge arm, and the conductive structure is also connected with the infrared absorption layer.

2. The picture element structure of claim 1, wherein The bridge arm comprises a first bridge arm and a second bridge arm, the bridge pier comprises a first bridge pier and a second bridge pier, the first bridge arm is connected with the first bridge pier, and the second bridge arm is connected with the second bridge pier; The conductive structure comprises a first conductive structure and a second conductive structure, one end of the infrared absorption layer is connected with the first bridge arm through the first conductive structure, and the other end of the infrared absorption layer is connected with the second bridge arm through the second conductive structure; The metasurface structure is located between the first conductive structure and the second conductive structure.

3. The picture element structure of claim 2, wherein, The bridge deck further comprises a first dielectric layer, the first dielectric layer is arranged between the infrared absorption layer and the metasurface structure; The infrared absorption layer comprises a main body part and first and second sub-parts located on both sides of the main body part respectively, the main body part overlaps with the first dielectric layer, the first sub-part overlaps with and is connected with the first conductive structure, and the second sub-part overlaps with and is connected with the second conductive structure.

4. The picture element structure of claim 3, wherein, The bridge deck further comprises a bridge deck support layer, the bridge deck support layer is located on a side of the infrared absorption layer away from the first dielectric layer; One end of the bridge deck support layer is located between the side of the infrared absorption layer and the first bridge arm and is connected with the first conductive structure; The other end of the bridge deck support layer is located between the side of the infrared absorption layer and the second bridge arm and is connected with the second conductive structure.

5. The picture element structure according to any one of claims 1 to 4, characterized in that The conductive structure and the metasurface structure are formed in the same thin film deposition process.

6. The picture element structure of claim 5, wherein, The conductive structure and the metasurface structure are made of the same material.

7. The picture element structure of claim 5 wherein, The conductive structure and the metasurface structure have the same thickness.

8. The picture element structure of claim 7, wherein, The thickness of the metasurface structure is less than or equal to 5000 angstroms.

9. The picture element structure according to any one of claims 1 to 4, characterized in that The bridge arm comprises a bridge arm support layer and a bridge arm conductive layer; The bridge arm support layer surrounds the bridge arm conductive layer, and the bridge arm conductive layer is connected with the conductive structure.

10. The picture element structure according to any one of claims 1 to 4, characterized in that The bridge deck further comprises a support column and an umbrella surface; The support column is arranged on a side of the metasurface structure away from the infrared absorption layer, the umbrella surface is arranged on a side of the support column away from the infrared absorption layer and is connected with the support column; The metasurface structure comprises at least one unit structure, and a projection of the support column on the infrared absorption layer is located within a projection of one of the unit structures on the infrared absorption layer.

11. The picture element structure of claim 10, wherein, The metasurface structure comprises a first unit structure and a plurality of second unit structures, and the plurality of second unit structures are arranged around the first unit structure; The projection of the support column on the infrared absorption layer is located within the projection of the first unit structure on the infrared absorption layer.

12. An infrared detector, characterized by The pixel structure and the imaging readout circuit are connected. The pixel structure and the imaging readout circuit are connected.

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