Monolithic integrated infrared focal plane array detector chip and design method thereof

Abstract

The invention discloses a monolithic integration-based infrared focal plane array detector chip and a design method thereof, the detector chip comprises a metasurface focusing layer and an infrared photosensitive chip, the infrared photosensitive chip comprises a photosensitive layer, an insulation bridge connected with the photosensitive layer and an interconnection electrode connected with the insulation bridge; the super-surface focusing layer focuses infrared light to the photosensitive layer, the photosensitive layer absorbs radiation energy and then causes deformation of the insulating bridge, the deformation causes change of current between the interconnected electrodes, and the intensity and distribution of infrared radiation can be judged by detecting the change of the current. The wide-spectrum focusing metasurface and the integrated photosensitive structure are combined, the capture and transmission efficiency of light energy is effectively improved, the responsiveness to infrared radiation of different wavelengths is enhanced, the sensitivity of the detector is improved, and good wavelength selectivity is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a monolithic integrated infrared focal plane array detector chip and a design method thereof. Background Art

[0002] Infrared focal plane array detectors are widely used in the field of infrared imaging and can be used for night vision, detection and security. The current infrared focal plane array detector technology mainly includes cooled and thermoelectric uncooled infrared imaging systems. However, these detectors have problems such as low sensitivity, low imaging resolution, high cost, and poor wavelength selectivity, which limits their application in the field of high-performance infrared imaging.

[0003] Compared with traditional infrared imaging systems, the optical readout uncooled infrared imaging technology based on micromechanical (MEMS) technology has the characteristics of low cost and simple optical path system; its system is generally composed of three parts: infrared lens, focal plane array and optical detection system. The optical detection system consists of three components, namely, the visible light readout module, lens group and optical filtering unit. The core of the whole system is the focal plane array, which is a surface array composed of multiple imaging units. Each imaging unit includes a micro mirror and a deformation mechanism, and usually adopts a dual-material micro cantilever structure. When the infrared lens focuses the infrared radiation on the pixel unit, the infrared absorption material absorbs the energy and converts it into the temperature increase of the deformation mechanism and the mirror. Due to the difference in the thermal expansion coefficient of the dual-material beam, deformation occurs, resulting in a certain angle change or out-of-plane displacement of the entire pixel unit. The temperature rise and angle change or out-of-plane displacement of each pixel unit are different. These angle changes or out-of-plane displacements are read by the optical detection system and converted into thermal images of the corresponding radiation source.

[0004] In the light-readout uncooled infrared imaging system based on micro-mechanical (MEMS) technology, the fill factor - the ratio of the area of ​​the photosensitive area to the area of ​​the pixel, is a key factor that restricts the entire micro-mechanical (MEMS) technology light-readout uncooled infrared imaging technology. Since the fill factor of the currently designed micro-mechanical (MEMS) technology light-readout uncooled infrared imaging technology is generally low, its energy transfer efficiency is limited to a very low level, which greatly restricts the sensitivity of the detector. Many design schemes solve these problems by adding lenses to the focal plane array detector. However, the focal plane detector chip after adding the lens faces problems such as large structure and volume, which makes the system integration low, increases the system complexity and cost, especially when it is necessary to process infrared radiation in multiple wavelength ranges at the same time, the performance improvement space of the traditional detector array chip is very limited, and it is difficult to meet the needs of high-precision and wide-wavelength infrared imaging.

[0005] In recent years, metasurface technology has attracted much attention because it can precisely control the phase, transmission, reflection and transmission of light. Metasurfaces achieve efficient control of light waves through the spatial layout of different subwavelength structures, so they are widely used in optical routing, optical imaging, optical communications, sensing and other fields. The infrared focal plane array detector chip based on the metasurface can efficiently operate infrared light and focus it on photosensitive areas of different shapes and positions, thereby improving the performance of the detector, including sensitivity, resolution and wavelength selectivity.

[0006] In current technology, focusing metasurfaces are usually implemented by combining multiple pieces, and have poor focusing effects on light of different wavelengths. They can only target photosensitive areas of specific shapes or positions and rely on the designer's prior knowledge. At the same time, existing design methods are not transferable. When designing for filling factors of different shapes or positions, they need to start from scratch, resulting in low design efficiency. Summary of the invention

[0007] In view of the above problems, the present invention provides a monolithic integrated infrared focal plane array detector chip and a design method thereof, aiming to improve the sensitivity, resolution and wavelength selectivity of the infrared focal plane array detector, which is beneficial to further expand its application in the field of infrared imaging.

[0008] The present invention is based on a monolithic integrated infrared focal plane array detector chip, including a super-surface focusing layer and an infrared photosensitive chip, wherein the infrared photosensitive chip includes a photosensitive layer, an insulating bridge connected to the photosensitive layer, and an interconnecting electrode connected to the insulating bridge; the super-surface focusing layer focuses infrared light onto the photosensitive layer, and the photosensitive layer absorbs radiation energy, causing the insulating bridge to deform, and the deformation causes a change in current between the interconnecting electrodes. The intensity and distribution of the infrared radiation can be determined by detecting the current change.

[0009] A further technical solution of the present invention is: the detector chip also includes a bottom reflector for reflecting infrared light to the photosensitive layer.

[0010] A further technical solution of the present invention is that the detector chip also includes a signal reading circuit for converting current changes into usable output signals.

[0011] A design method based on a monolithic integrated infrared focal plane array detector chip includes designing a metasurface focusing layer and an infrared photosensitive chip, specifically including:

[0012] According to the application requirements of the infrared photosensitive chip, the structure of the infrared photosensitive chip is designed to include a photosensitive layer, an insulating bridge connected to the photosensitive layer, and an interconnecting electrode connected to the insulating bridge;

[0013] Determine the thickness and super-atomic structure of the super-surface focusing layer according to the structure of the infrared photosensor chip and application requirements;

[0014] A light energy distribution objective function is established based on the thickness of the metasurface focusing layer and the meta-atomic structure, and an optimized metasurface focusing layer is obtained by optimizing the meta-atomic structure until the light energy distribution objective function converges or reaches an extreme value.

[0015] A further technical solution of the present invention is: the photosensitive layer includes a substrate and a semiconductor material on the surface of the substrate, and the semiconductor material includes silicon or germanium.

[0016] A further technical solution of the present invention is: a structure of photosensitive areas is formed on the surface of the photosensitive layer by micro-nano processing technology, and the photosensitive areas are arranged in an array structure, and the shape of the array structure is any one or more combinations of cylindrical, rectangular, triangular, and pentagonal shapes.

[0017] A further technical solution of the present invention is: the interconnecting electrodes are connected to both ends of the photosensitive area or both ends of the insulating bridge frame through a metallization process.

[0018] A further technical solution of the present invention is: the specific expression of the light intensity distribution objective function is:

[0019]

[0020] Where λ represents the wavelength of light, I0(λ) is the set light target intensity curve, and I K (p) is the light target intensity curve actually generated by iteration, p is the super-atomic structure, λ1 and λ2 are the minimum wavelength and maximum wavelength of the corresponding band, respectively, preferably 8 μm and 11 μm.

[0021] A further technical solution of the present invention is: based on the light intensity distribution objective function, the super-atom structure parameter p is optimized until the objective function reaches convergence and extremum, and the specific method is: obtaining the super-surface focusing layer through T-matrix and adjoint method design.

[0022] A further technical solution of the present invention is: the supersurface focusing layer is integrated and bonded with the infrared photosensor chip through an optical adhesive layer or a liquid optical adhesive layer, and the supersurface focusing layer overlaps with the photosensitive chip.

[0023] The present invention provides a monolithic integrated infrared focal plane array detector chip and its design method. Compared with the traditional infrared focal plane array detector chip, the present invention combines a wide-spectrum focusing metasurface and an integrated photosensitive structure, effectively improving the capture and transmission efficiency of light energy, and enhancing the response capability to infrared radiation of different wavelengths. It not only improves the sensitivity of the detector, but also has good wavelength selectivity. Its beneficial effects are as follows:

[0024] 1. The present invention provides a target-driven inverse design method, which sets different light-collecting areas for different photosensitive areas. The method is not limited to specific target functions and does not rely on the geometric characteristics of the optical structure and the design experience of the designer.

[0025] 2. The monolithic integrated wide-spectrum focusing metasurface infrared focal plane array detector chip provided by the present invention directly acts on the incident light field and focuses it on the photosensitive area, without the need for additional lenses. The overall size of the device is in the micron range, and it has the characteristics of compact structure and small size. The metasurface structure can be directly manufactured on the photosensitive chip substrate material.

[0026] 3. The monolithic integrated wide-spectrum focusing metasurface infrared focal plane array detector chip provided by the present invention operates at infrared wavelengths. After the metasurface within the unit periodic structure is pixelated, the scale of each pixel unit is in the micron order, and the device contains only two dielectric materials, which is conducive to directly preparing samples using dual-photopolymerization 3D printing technology.

[0027] 4. The monolithic integrated wide-spectrum focusing metasurface infrared focal plane array detector chip provided by the present invention can realize efficient focusing and control of infrared light waves, and has the characteristics of low loss and wide spectrum. It can effectively improve the sensitivity, resolution and wavelength selectivity of the infrared focal plane array detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of a monolithic integrated infrared focal plane array detector chip according to an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the flow of a design method based on a monolithic integrated infrared focal plane array detector chip according to an embodiment of the present invention;

[0030] Figure 3 It is a top view of the microstructure of a monolithic integrated infrared focal plane array detector chip according to an embodiment of the present invention;

[0031] Figure 4 The embodiment of the present invention is based on Figure 1 Schematic diagram of the light collection efficiency curve obtained by the design;

[0032] Figure 5 This is a design principle diagram of a monolithic integrated infrared focal plane array detector chip according to an embodiment of the present invention;

[0033] Figure 6 This is a focusing effect diagram of a photosensitive area created based on a rectangular filling factor of 50um*50um in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0036] The present invention is based on a monolithic integrated infrared focal plane array detector chip, which improves the sensitivity, resolution, wavelength selectivity and other performances of the infrared focal plane array detector, and is beneficial to further expand its application in the field of infrared imaging.

[0037] The present invention is based on a monolithic integrated wide-spectrum focusing metasurface infrared focal plane array detector chip and a design method thereof. The chip consists of two parts: a metasurface focusing layer and an infrared photosensitive chip. First, the infrared light is focused onto the photosensitive area on the photosensitive chip through the integrated metasurface layer. The photosensitive area is connected to two insulating bridges. When the infrared radiation energy irradiates the photosensitive area, the photosensitive area absorbs the radiation energy and causes the insulating bridge where the photosensitive area is located to deform. Since the insulating bridge is connected to the interconnecting electrodes, the deformation will cause a change in the current. By detecting the change in the current, the intensity and distribution of the infrared radiation can be accurately determined, thereby achieving high-sensitivity and high-resolution infrared radiation detection.

[0038] Specifically, Figure 1 As shown, a monolithic integrated infrared focal plane array detector chip includes a metasurface focusing layer 2 and an infrared photosensitive chip, wherein the infrared photosensitive chip includes a photosensitive layer 4, an insulating bridge frame 7 connected to the photosensitive layer 4, and an interconnecting electrode 5 connected to the insulating bridge frame 7; the metasurface focusing layer 2 focuses infrared light onto the photosensitive layer 4, and the photosensitive layer 4 absorbs radiation energy, causing the insulating bridge frame 7 to deform, and the deformation causes a change in the current between the interconnecting electrodes 5, and the intensity and distribution of the infrared radiation can be determined by detecting the current change.

[0039] like Figure 1 As shown, the detector chip further includes a bottom reflector 6 for reflecting infrared light to the photosensitive layer 4 .

[0040] The detector chip also includes a signal reading circuit (not shown in the figure) for converting the current change into a usable output signal.

[0041] In a specific embodiment, Figure 1 As shown in the figure, the photosensitive area is a 50um×50um rectangle. The designed infrared light of 8-11um is concentrated in this area after passing through the metasurface focusing layer, generating an electrical signal and causing the current of the photosensitive chip to change, thereby detecting the infrared radiation energy. Above the photosensitive chip is a metasurface focusing layer of the same size, which is an artificial micro-nano structure made of SiO2 and composed of 100 cylinders with a height of 2um. It focuses the target wavelength in the photosensitive area, thereby improving the sensitivity, resolution and wavelength selectivity of the infrared focal plane array detector.

[0042] The purpose of the present invention is to solve the deficiencies of existing infrared focal plane array detector chips in terms of light energy utilization efficiency, response sensitivity, imaging resolution and wavelength selectivity. Infrared detectors in the prior art have the problem of low light energy utilization efficiency, and cannot fully capture and focus on the incident infrared radiation, resulting in waste of light energy, thereby affecting the detection accuracy and sensitivity. At the same time, the response sensitivity of these detectors is low, and they cannot accurately detect weak infrared radiation signals, resulting in a low signal-to-noise ratio. In addition, due to the limitations of the size of photosensitive elements and the bottleneck of structural design, the imaging resolution of many infrared detectors cannot meet the needs of high-precision imaging. Existing detectors also generally have the problem of poor wavelength selectivity, and usually can only respond to infrared radiation in a specific wavelength range, resulting in limited applicability. In addition to the performance bottleneck, many infrared detectors also face problems such as large structural volume, which makes the system integration low, increases the system complexity and cost, especially when it is necessary to process infrared radiation in multiple wavelength ranges at the same time, the performance improvement space of traditional detectors is very limited, and it is difficult to meet the needs of high-precision, wide wavelength range infrared imaging. In order to solve the above problems, the present invention provides an infrared focal plane array detector chip based on a monolithic integrated wide-spectrum focusing metasurface. Through innovative optical path design and structural integration, the light energy utilization efficiency, response sensitivity and wavelength selectivity are significantly improved, thereby achieving high-resolution and high-precision infrared imaging.

[0043] A design method based on a monolithic integrated infrared focal plane array detector chip, including designing a metasurface focusing layer and an infrared photosensitive chip, such as Figure 2 As shown, specifically including:

[0044] S1. According to the application requirements of the infrared photosensor chip, the structure of the infrared photosensor chip is designed to include a photosensitive layer, an insulating bridge connected to the photosensitive layer, and an interconnecting electrode connected to the insulating bridge;

[0045] Specifically, according to the application requirements of the photosensitive chip (such as response wavelength range, sensitivity, size, etc.), its basic microstructure is determined;

[0046] S2. Determine the thickness and super-atomic structure of the super-surface focusing layer according to the structure of the infrared photosensor chip and application requirements;

[0047] Specifically, the design parameters of the supersurface focusing layer are determined according to the set photosensitive chip and the supersurface semiconductor material, and the parameters include: the thickness of the supersurface focusing layer and the basic structure of the contained superatoms;

[0048] S3. Establishing a light energy distribution objective function based on the thickness of the metasurface focusing layer and the meta-atomic structure, and obtaining an optimized metasurface focusing layer by optimizing the meta-atomic structure until the light energy distribution objective function converges or reaches an extreme value.

[0049] Specifically, the design parameters of the supersurface focusing layer are determined according to the set photosensitive chip and the supersurface semiconductor material, and the parameters include: the thickness of the supersurface focusing layer and the basic structure of the contained superatoms.

[0050] The photosensitive layer includes a substrate and a semiconductor material on the surface of the substrate, wherein the semiconductor material includes silicon or germanium.

[0051] The structure of the photosensitive area is formed on the surface of the photosensitive layer by micro-nano processing technology. The photosensitive area is arranged in an array structure. The shape of the array structure is any one or more combinations of cylindrical, rectangular, triangular, and pentagonal.

[0052] The interconnecting electrodes are connected to both ends of the photosensitive area or both ends of the insulating bridge through a metallization process.

[0053] Based on the target model of light energy distribution, the meta-atom structure parameter p is optimized until the objective function reaches convergence and extremum. The specific method is: the metasurface focusing layer is obtained by designing through T-matrix and adjoint method.

[0054] The super-surface focusing layer is integrated and bonded with the infrared photosensor chip through an optical adhesive layer or a liquid optical adhesive layer, and the super-surface focusing layer overlaps with the photosensor chip.

[0055] In a specific embodiment, first, according to the application requirements of the photosensitive chip (such as response wavelength range, sensitivity, size, etc.), its basic structure needs to be determined. The photosensitive chip is usually composed of a substrate, a photosensitive layer, an insulating layer, a bridge and an electrode. The photosensitive layer should select semiconductor materials suitable for the infrared band, such as silicon (Si), germanium (Ge) or other materials suitable for the infrared spectrum to ensure a good response to infrared radiation. The substrate material should select a material with good mechanical stability and good combination with the photosensitive layer. The key part of the photosensitive chip is the photosensitive area, which is responsible for absorbing infrared radiation and generating electrical signals. To this end, it is necessary to use micro-nano processing technology (such as photolithography, electron beam etching, etc.) to accurately form the structure of the photosensitive area on the chip surface. The shape, size and arrangement of the photosensitive area have an important influence on the response sensitivity and spatial resolution of the chip. The size of the photosensitive area should match the super surface focusing area to ensure that the light energy can be effectively transmitted, and the arrangement method can adopt an array structure to cover the entire detection area to form an infrared focal plane array. The insulating bridge is a key structure connecting the photosensitive area and the electrode, and its function is to transmit the deformation signal generated by the photosensitive area to the electrode. The bridge is usually made of high-temperature-resistant and high-insulation materials (such as silicon oxide), and by optimizing its position and shape, it ensures that it can undergo appropriate deformation when receiving infrared radiation energy to effectively transmit the signal to the electrode. The design of the electrode needs to ensure the efficiency and stability of signal transmission. The electrode is usually made of metal materials (such as aluminum, gold or copper) and is connected to the photosensitive area and the bridge through a metallization process. The layout of the electrodes is distributed at both ends of the photosensitive area or at both ends of the bridge to ensure that the current path is unobstructed and the signal can be accurately collected and transmitted. After the photosensitive chip is designed, it is also necessary to design a signal reading circuit to convert the current changes generated by the photosensitive area into a usable output signal. According to the needs, suitable amplifier circuits, analog-to-digital converters (ADCs) and other signal processing units can be selected to ensure that the current changes can be accurately read and processed.

[0056] The shape, size and arrangement of the photosensitive area will affect the response sensitivity and spatial resolution of the chip. The photosensitive area can be arranged in an array structure to cover the entire detection area to form an infrared focal plane array, and its shape can be any one or any combination of cylindrical, rectangular, triangular, pentagonal, etc.

[0057] The design parameters of the metasurface focusing layer are determined according to the set photosensitive chip and metasurface semiconductor material, specifically:

[0058] According to the size of the photosensitive chip, the same plane area corresponding to the metasurface is selected as the design area; the metasurface scale is in the micron order and the structure of the metasurface can be in the shape of an ellipsoid, a sphere, a cylinder, etc., which can be directly prepared by dual-photopolymerization 3D printing technology. The specific selection can be determined according to the design goal. According to the size of the metasurface focusing layer, the type and quantity of metaatoms and the corresponding thickness h of the metasurface focusing layer are set; the light field intensity of the scattered field on the focal plane detector after passing through the metasurface focusing layer is calculated.

[0059] Establish an optimization model based on the metasurface design parameters and output an optimization plan, including:

[0060] Establish the light intensity distribution objective function, such as the following formula;

[0061]

[0062] Where I0(λ) is the target intensity curve. Here we set the target area of ​​​​the spotlight according to the position and shape of the photosensitive area. K (p) is the intensity curve actually generated by iteration, and p is the superatomic structure. For an ellipse, the optimized structure can be the major axis a, b, c of the ellipse or the angle between the ellipse and the z axis. For a sphere, the optimized structure may be the radius r of the circle. For a cylinder, the optimized structure may be the cylinder radius r or the cylinder height h. λ represents the wavelength of light, λ1 and λ2 are the minimum wavelength and maximum wavelength of the corresponding band, respectively, and preferably 8 μm and 11 μm in the embodiment.

[0063] Based on the above light energy distribution target model, the superatom structure parameter p is optimized until the objective function reaches convergence and extremum, including:

[0064] Si3N4 material is used, and the cylinder is selected as the super-atom structure. According to the set objective function, T-matrix is ​​selected as the electromagnetic solver and the adjoint method is selected as the gradient descent optimization algorithm to optimize the radius r of the cylinder. The super-surface focusing layer obtained by T-matrix and adjoint method design is shown in Figure 2. Figure 3 shown.

[0065] For a single particle, i = 1

[0066]

[0067] Where E in represents the incident field, represents the incident field coefficient, represents the scattered field coefficient, r i represents the coordinates of the center of the ith particle, represents the incoming spherical wave function, Represents the outgoing spherical wave function. Through the T-matrix, the relationship between the incident field and the scattered field of a single particle can be established:

[0068]

[0069] For a system consisting of multiple particles, the total incident field on the i-th particle is equal to the initial field E in , plus the scattered field E contributed by other particles j sact :

[0070]

[0071] E in,all The scattered field of any sphere j must be converted into the incident field of other spheres. To achieve this goal, the incident field The same basis vector function is used to represent the scattered field But the corresponding reference coordinate system is different. Through the addition principle, one basis vector can be expressed as the expanded form of another basis vector. The changing relationship between these basis vectors can be summarized in a coupling matrix W. In this way, a new set of incident coefficients can be defined for each particle in the collection:

[0072]

[0073] Substituting the incident field coefficient (1.5) into the linear equation (1.3)

[0074]

[0075] Next, moving the scattered field coefficient to the same side of the equation, we finally get:

[0076]

[0077] So we can get the objective function For structure A j The gradient is:

[0078]

[0079] Derivative both sides of equation (1.7):

[0080]

[0081] Then the FOM with respect to the structural parameter A can be easily obtained by the chain rule j However, for a large system, it is difficult to calculate the gradient of It requires a lot of resources and time. Therefore, after solving the forward problem, After that, the accompanying variable L is introduced:

[0082]

[0083] By solving equation (1.13), we can obtain the adjoint variable L, which can save a lot of computing resources. And bring it back to equation (1.11):

[0084]

[0085] After getting the gradient, update the parameters:

[0086]

[0087] A top view of the microstructure design of a monolithic integrated broadband focusing metasurface infrared focal plane array detector chip based on a 50um*50um rectangular filling factor design, where the designed array consists of 100 nano-cylinders with a refractive index of 1.52. The metasurface focusing layer is 100um×100um in size and consists of 100 cylinders, each of which is 2um in height. This monolithic integrated broadband focusing metasurface infrared focal plane array detector chip has been verified through full-wave electromagnetic computing simulation, and the light efficiency of each central band (wavelength set to 8um, 9um, 10um, and 11um) is as follows Figure 4 As shown, Figure 4 The embodiment of the present invention is based on Figure 1 The light collection efficiency curve obtained by the design, the solid line represents the light collection efficiency of 8-11um infrared light in the receiving area, and the dotted line represents the light collection efficiency of the photosensitive area created based on a rectangular filling factor of 50um*50um. The average light energy utilization rate is higher than 60%, which is better than the traditional infrared focal plane array detector chip.

[0088] Specifically, Figure 5 As shown, it is a schematic diagram of the design principle of the infrared focal plane array detector chip of the monolithic integrated wide-spectrum focusing metasurface provided by an embodiment of the present invention. First, the target light intensity I0(λ) is set according to the position and shape of the filling factor, and the meta-atom (cylinder) is optimized. The radius r of each cylinder is used as the design parameter, and a random initial structure is set as the initial value of r. In each optimization iteration process, an electromagnetic solver is used to calculate the scattered field light intensity I K (r), the FOM value is calculated once for each iteration, and the design parameter r is updated in combination with the adjoint algorithm during the optimization iteration. The smaller the objective function FOM is, the closer the target light field intensity I0(λ) is to the scattered light field intensity I generated by the actual iteration. k The closer (r) is, when the objective function FOM converges, the nanocylindrical structure generated on the metasurface is the optimal structure.

[0089] Figure 6 The photosensitive area created based on a rectangular filling factor of 50um*50um provided in an embodiment of the present invention has a (8-11um) infrared light field intensity simulation result corresponding to a specific design on the imaging plane. From the figure, it can be intuitively observed that the (8-11um) infrared light achieves a good focusing effect in the created rectangular photosensitive area.

[0090] The monolithic integrated infrared focal plane array detector chip and its design method provided in the above embodiments, compared with the traditional infrared focal plane array detector chip, the present invention combines a wide-spectrum focusing metasurface and an integrated photosensitive structure, effectively improving the capture and transmission efficiency of light energy, and enhancing the response capability to infrared radiation of different wavelengths, which not only improves the sensitivity of the detector, but also has good wavelength selectivity.

[0091] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A monolithic integrated infrared focal plane array detector chip, characterized in that: It includes a supersurface focusing layer and an infrared photosensitivity chip, wherein the infrared photosensitivity chip includes a photosensitivity layer, an insulating bridge connected to the photosensitivity layer, and interconnecting electrodes connected to the insulating bridge; the supersurface focusing layer focuses infrared light onto the photosensitivity layer, and the photosensitivity layer absorbs radiation energy, causing the insulating bridge to deform, and the deformation causes a change in the current between the interconnecting electrodes. The intensity and distribution of the infrared radiation can be determined by detecting the current change.

2. The monolithic integrated infrared focal plane array detector chip according to claim 1, characterized in that: The detector chip also includes a bottom reflector for reflecting infrared light to the photosensitive layer.

3. The monolithic integrated infrared focal plane array detector chip according to claim 1, characterized in that: The detector chip also includes a signal reading circuit for converting current changes into usable output signals.

4. A design method based on a monolithic integrated infrared focal plane array detector chip, characterized in that: Including the design of metasurface focusing layer and infrared photosensitive chip, including: According to the application requirements of the infrared photosensitive chip, the structure of the infrared photosensitive chip is designed to include a photosensitive layer, an insulating bridge connected to the photosensitive layer, and an interconnecting electrode connected to the insulating bridge; Determine the thickness and super-atomic structure of the super-surface focusing layer according to the structure of the infrared photosensor chip and application requirements; A light energy distribution objective function is established based on the thickness of the metasurface focusing layer and the meta-atomic structure, and an optimized metasurface focusing layer is obtained by optimizing the meta-atomic structure until the light energy distribution objective function converges or reaches an extreme value.

5. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 4, characterized in that: The photosensitive layer includes a substrate and a semiconductor material on the surface of the substrate, and the semiconductor material includes silicon or germanium.

6. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 4, characterized in that: The structure of the photosensitive area is formed on the surface of the photosensitive layer by micro-nano processing technology. The photosensitive area is arranged in an array structure. The shape of the array structure is any one or more combinations of cylindrical, rectangular, triangular, and pentagonal.

7. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 4, characterized in that: The interconnecting electrodes are connected to the two ends of the photosensitive area or the two ends of the insulating bridge frame through a metallization process.

8. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 4, characterized in that: The specific expression of the light intensity distribution objective function is: Where λ represents the wavelength of light, I0(λ) is the set light target intensity curve, and I K (p) is the actual iteratively generated light target intensity curve, p is the super-atom structure, λ1 and λ2 are the minimum wavelength and maximum wavelength of the corresponding band, respectively.

9. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 8, characterized in that: Based on the light intensity distribution objective function, the meta-atom structure parameter p is optimized until the objective function reaches convergence and extremum. The specific method is: the metasurface focusing layer is obtained by designing through T-matrix and adjoint method.

10. The design method based on a monolithic integrated infrared focal plane array detector chip according to claim 4, characterized in that: The super-surface focusing layer is integrated and bonded with the infrared photosensor chip through an optical adhesive layer or a liquid optical adhesive layer, and the super-surface focusing layer overlaps with the photosensor chip.

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