Infrared photoelectric detector based on super lens and manufacturing method thereof

Abstract

The invention relates to the technical field of semiconductor devices, in particular to an infrared photoelectric detector based on a super lens and a manufacturing method of the infrared photoelectric detector. The infrared photoelectric detector based on the super lens comprises a tube socket, a metal tube cap and a detector chip, the metal tube cap and the tube socket are fixedly connected and form a totally-enclosed packaging structure, the detector chip is packaged between the tube socket and the metal tube cap, a chip electrode of the detector chip is welded with a pin of the tube socket, the super lens is arranged at the top of the metal tube cap, and the super lens is arranged on the top of the metal tube cap. The side wall is a metal tube shell, and the super lens comprises a super lens substrate and super lens units periodically arranged above the super lens substrate. According to the infrared photoelectric detector based on the super lens, the super lens units periodically arranged on the super lens can be utilized, the transmittance of incident light can be improved, the interference effect of reflected light can be restrained, and then the detection rate of the infrared photoelectric detector is improved.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor devices, and particularly to an infrared photodetector based on a metalens and a manufacturing method thereof. Background Art

[0002] An infrared photodetector is a device that detects infrared radiation based on the photoelectric effect. When infrared radiation irradiates the photosensitive material of the detector, the photon energy of the infrared radiation is absorbed by the photosensitive material, causing electrons in the photosensitive material to transition from the valence band to the conduction band, forming photo-generated carriers. These photo-generated carriers move directionally under the action of an externally applied electric field or an internal built-in electric field, thereby generating electrical signals such as photocurrent or photovoltage, realizing the conversion from an infrared light signal to an electrical signal, and then completing the detection of infrared light.

[0003] The photoelectric conversion efficiency of an infrared photodetector is used to characterize the effective degree of energy conversion during the conversion process from an infrared light signal to an electrical signal. Currently, the photoelectric conversion efficiency of infrared detectors is low, resulting in most of the light being reflected, generating interference noise, reducing the photoelectric performance of the detector, and restricting the development of high-detection-rate infrared detectors.

[0004] By setting the infrared photodetector in a transistor outline (TO) package structure and using a convex lens to achieve focusing, the light incident efficiency can be improved. And by evaporating an antireflection film on the surface of the convex lens, the light transmittance incident into the chip can be increased. However, the above method will result in a relatively high light reflection effect, which cannot meet the requirements for multi-gas detection and low-concentration gas detection, and the reflected light will generate an interference effect in the infrared detection system, reducing the detection performance of the infrared photodetector.

[0005] Therefore, there is an urgent need to propose a new method to solve the above technical problems. Summary of the Invention

[0006] This application discloses an infrared photodetector based on a metalens and a manufacturing method thereof, which improves the transmittance of incident light of the infrared photodetector, suppresses the interference effect of reflected light, and further improves the detection rate of the infrared photodetector.

[0007] In some embodiments, an infrared photodetector based on a metalens is provided, including: a header, a metal cap, and a detector chip encapsulated between the header and the metal cap; the header includes a bottom plate and pins, the pins are disposed on a first surface of the bottom plate, and the first surface is the surface of the header facing the metal cap; the detector chip is an infrared detector unit device, the detector chip is fixed on the first surface of the header based on a non-conductive adhesive, the detector chip includes chip electrodes, and the chip electrodes are welded to the pins; the metal cap is a columnar structure with an open bottom, the top of the metal cap is a metalens, and the side wall is a metal tube shell, and the bottom of the metal tube shell is fixed on the first surface of the header to form a fully enclosed packaging structure; the metalens includes a metalens substrate and a metalens array, the metalens substrate is used to support the metalens array, and the metalens array includes a plurality of metalens units, and the plurality of metalens units are periodically arranged above the metalens substrate.

[0008] When using the infrared photodetector based on a metalens provided by the embodiments of the present application, when an infrared radiation signal is incident on the detector chip through the metalens at the top of the metal cap, the infrared radiation signal can be converted into an electrical signal, thereby realizing the detection of the infrared photodetector. When the infrared radiation signal is incident on the metalens, the metalens units periodically arranged on the surface of the metalens can reduce the reflection loss of the broadband signal in the infrared radiation signal, improve the transmittance of the incident light of the infrared photodetector, and suppress the interference effect of the reflected light, thereby improving the detection rate of the infrared photodetector.

[0009] Optionally, the pins include a first pin and a second pin, the chip electrodes include a p-type electrode and an n-type electrode, the first pin is welded to the p-type electrode, and the second pin is welded to the n-type electrode.

[0010] Optionally, the interior of the packaging structure formed by the header and the metal cap is vacuum or an inert gas.

[0011] Optionally, the metalens is configured to regulate the optical phase of the incident light so that the optical phase of the incident light after passing through the metalens has a phase change in amplitude; the arrangement distance of the metalens units is less than or equal to , and the arrangement distance is used to characterize the distance between two adjacent metalens units.

[0012] Optionally, the metalens unit is a cylindrical structure, the bottom diameter of the metalens unit is equal to the arrangement distance of the metalens units; the height of the metalens unit is 0.4 to 0.6 times of a preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip.

[0013] Optionally, the hyperlens unit ring is provided with a groove, and the groove wall of the groove includes a vertical section, a first transition section, and a second transition section. The included angle between the vertical section and the first transition section is a first preset angle, and the included angle between the vertical section and the second transition section is a second preset angle. The first preset angle is greater than or equal to the second preset angle, and the length of the first transition section is less than or equal to the length of the second transition section. The height of the hyperlens unit is 0.4 to 0.6 times the preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip. The height of the vertical section is 0.2 to 0.3 times the height of the hyperlens unit.

[0014] Optionally, the hyperlens unit is axially symmetric about a first axis, the first axis is perpendicular to the surface where the hyperlens substrate is located, the bottom surface of the hyperlens unit is circular, and the diameter of the bottom surface of the hyperlens unit is equal to the arrangement distance of the hyperlens units.

[0015] Optionally, the detector chip includes a substrate layer, a p-type layer, a p-type electrode, an absorption layer, an n-type layer, and an n-type electrode stacked in sequence from top to bottom.

[0016] Optionally, the detector chip includes a p-type electrode, a substrate layer, a p-type layer, an absorption layer, an n-type layer, and an n-type electrode stacked in sequence from top to bottom.

[0017] In some embodiments, a method for manufacturing an infrared photodetector based on a hyperlens is provided, including: providing a header, a hyperlens, a metal package, and a detector chip, where the header includes pins; welding the detector chip to the pins and applying glue at the bottom of the detector chip to fix the detector chip to the installation area of the header; etching a hyperlens substrate and a hyperlens array on the hyperlens, where the hyperlens array includes a plurality of hyperlens units, and the plurality of hyperlens units are periodically arranged above the hyperlens substrate; welding the hyperlens to the metal package to obtain a metal cap, where the top of the metal cap is the hyperlens and the side wall is the metal package; welding the metal cap above the header in a vacuum environment or an inert gas environment so that the detector chip is encapsulated between the header and the metal cap.

[0018] It can be understood that for the beneficial effects that can be achieved by the above-provided method for manufacturing an infrared photodetector based on a hyperlens, reference can be made to the beneficial effects in the infrared photodetector based on a hyperlens and any of its optional embodiments, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0020] Figure 1Structural diagram of an infrared photodetector based on a metalens provided by an embodiment of the present application; Figure 2 Top view of a header provided by an embodiment of the present application; Figure 3 Schematic diagram of an arrangement structure of a metalens unit provided by an embodiment of the present application; Figure 4 Another schematic diagram of an arrangement structure of a metalens unit provided by an embodiment of the present application; Figure 5 Schematic diagram of a waist-shaped structure of a metalens unit provided by an embodiment of the present application; Figure 6 Flowchart of a manufacturing method of an infrared photodetector based on a metalens provided by an embodiment of the present application.

[0021] Reference numerals: 1. Header; 11. Bottom plate; 12. Pin; 121. First pin; 122. Second pin; 123. Ground wire; 2. Metal tube cap; 21. Metalens; 22. Metal tube shell; 211. Metalens substrate; 212. Metalens array; 2121. Metalens unit; 21211. Vertical section; 21212. First transition section; 21213. Second transition section; 3. Detector chip. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present application will be clearly described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0023] Hereinafter, terms such as "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0024] In addition, in the present application, orientation terms such as "upper", "lower", "inner", "outer", etc. are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and they may change accordingly with the change of the orientation of the components placed in the accompanying drawings.

[0025] For the convenience of understanding the technical solution of the application, the related technologies involved in the present application are described below first.

[0026] An infrared photodetector is a device used to detect infrared radiation. Its working principle is based on the photoelectric effect, which can convert infrared radiation signals into electrical signals. Infrared photodetectors can be applied to target detection and tracking in the military field, intrusion detection in the security field, etc.

[0027] The structure of an infrared photodetector generally includes an optical system and a detection element. Among them, the optical system usually consists of a lens, a mirror, a filter, etc. The lens and the mirror are used to converge and guide infrared light, and the filter is used to select infrared radiation within a specific wavelength range. The optical system collects and focuses infrared radiation so that it effectively irradiates the detection element. The detection element is used to convert the received infrared radiation into an electrical signal.

[0028] When infrared light irradiates the photosensitive material of the detector, the photon energy is absorbed by the material, causing electrons in the material to transition from the valence band to the conduction band, forming photo-generated carriers. These photo-generated carriers move directionally under the action of an externally applied electric field or the built-in electric field inside the material, thereby generating electrical signals such as photocurrent or photovoltage, realizing the conversion from infrared light signals to electrical signals, and then completing the detection of infrared light.

[0029] In order to protect the optical system and the detection element inside the infrared photodetector from the influence of the external environment, a metal or plastic shell is usually adopted, with internal sealing treatment and an optical window is provided so that infrared radiation can enter the detector, thereby achieving the purposes of moisture-proof, dust-proof, electromagnetic interference prevention, etc.

[0030] Since some infrared light will be reflected or scattered on the surface of the detector, only part of the infrared light is absorbed for photoelectric conversion, which will result in a low photoelectric conversion efficiency of the infrared detector and limit the photoelectric performance of the detector. By setting the infrared photodetector into a packaging structure with a transistor outline (TO), and using a convex lens to achieve focusing, the light incident efficiency can be improved. And by evaporating an antireflection film on the surface of the convex lens, the light transmittance incident into the chip can be increased. However, the above methods will result in a relatively high light reflection effect, which cannot meet the requirements for multi-gas detection and low-concentration gas detection, and the reflected light will generate an interference effect in the infrared detection system, reducing the detection performance of the infrared photodetector.

[0031] By setting the infrared photodetector in a Transistor Outline (TO) package structure and using a convex lens for focusing, the light incident efficiency can be improved. Among them, the TO package structure is usually cylindrical in shape and made of metal material, which helps to achieve good thermal conduction and electrical insulation performance. The top of the TO package structure is provided with a convex lens to facilitate the passage of light, and by evaporating an antireflection film on the surface of the convex lens, the light transmittance incident into the chip can be enhanced.

[0032] However, the TO package structure with a convex lens at the top still results in a relatively high light reflection effect, which cannot meet the requirements for multi-gas detection and low-concentration gas detection. Moreover, in the infrared detection system, the reflected light will produce an interference effect, reducing the detection performance of the infrared photodetector.

[0033] Figure 1 The structural diagram of the infrared photodetector based on a metasurface provided by an embodiment of the present application Figure 2 The top view of the header provided by an embodiment of the present application Figure 3 A schematic diagram of an arrangement structure of a metasurface unit provided by an embodiment of the present application.

[0034] To solve the problems existing in the above related technologies, as shown in combination with Figure 1 、 Figure 2 and Figure 3 An embodiment of the present application provides an infrared photodetector based on a metasurface, including: a header 1, a metal cap 2, and a detector chip 3 encapsulated between the header 1 and the metal cap 2. Among them, the header 1 includes a base plate 11 and pins 12, and the pins 12 are arranged on the first surface of the base plate 11, and the first surface is the surface of the header 1 facing the metal cap 2.

[0035] The detector chip 3 is an infrared detector unit device. The detector chip 3 is fixed on the first surface of the header 1 based on a non-conductive adhesive. The detector chip 3 includes chip electrodes, and the chip electrodes are welded to the pins 12; the metal cap 2 is a columnar structure with an open bottom. The top of the metal cap 2 is a metasurface 21, and the side wall is a metal shell 22. The bottom of the metal shell 22 is fixed on the first surface of the header 1 to form a fully enclosed package structure.

[0036] The metasurface 21 includes a metasurface substrate 211 and a metasurface array 212. The metasurface substrate is used to support the metasurface array 212. The metasurface array 212 includes a plurality of metasurface units 2121, and the plurality of metasurface units 2121 are periodically arranged above the metasurface substrate 211.

[0037] In some embodiments, the detector chip 3 is an infrared detector unit device. The detector chip 3 is a semiconductor device that can detect infrared radiation and convert the infrared radiation into a measurable electrical signal. The detector chip 3 is fixed on the first surface of the header 1. Exemplarily, the gold wire is melted by heating, and the chip electrodes of the detector chip 3 are welded to the pins 12 of the header 1. Further, non-conductive glue is dot-coated under the detector chip 3 to fix the detector chip 3 at a preset position on the header 1, improving the firmness of the connection between the detector chip 3 and the header 1.

[0038] The metal cap 2 has a columnar structure with an open bottom. The opening of the metal cap 2 is welded to the first surface of the header 1 to form a fully enclosed packaging structure. This enclosed structure can isolate the detector chip 3 from the outside world, effectively blocking external water vapor, oxygen, and various corrosive gases and liquids, preventing chemical reactions between the materials such as metals and semiconductors inside the detector chip 3 and the outside world. And it can protect the cleanliness inside the infrared photodetector based on the meta-lens, enabling infrared light to reach the detector chip 3 through the meta-lens, improving the detection accuracy and sensitivity of the infrared photodetector.

[0039] The top of the metal cap 2 is a meta-lens 21. The meta-lens 21 is a meta-surface structure lens. The meta-surface structure lens is a two-dimensional planar lens composed of a large number of micro-nano structures (meta-atoms). By precisely adjusting the characteristics such as the shape, rotation direction, and height of the micro-nano structures, the meta-lens 21 can perform specific regulation on the incident infrared light.

[0040] The meta-lens 21 includes a meta-lens substrate 211 and a meta-lens array 212. Among them, the meta-lens substrate 211 is used to support the meta-lens array 212. The meta-lens array 212 includes a plurality of meta-lens units 2121. The plurality of meta-lens units 2121 are periodically arranged above the meta-lens substrate 211 through a preset pattern. In this way, the meta-lens array 212 can change the phase distribution of the incident light, causing the incident light beam to be redirected, achieving the focusing of light and the change of phase.

[0041] The redirection of the incident light beam means that when light enters from one medium into another medium, due to the different refractive indices of different media, the incident light will change its propagation direction. For example, when infrared light passes through the meta-lens 21, due to the different refractive indices of the lens material and air, the light is refracted on the upper and lower surfaces of the meta-lens 21, causing the light to converge or diverge, thereby achieving the redirection of the incident light.

[0042] The infrared photodetector based on the meta-lens can utilize the meta-lens units periodically arranged on the meta-lens to improve the transmittance of the incident light and can suppress the interference effect of the reflected light, thereby improving the detection rate of the infrared photodetector.

[0043] In some embodiments, pin 12 includes a first pin 121 and a second pin 122. The chip electrodes of the detector chip 3 include a p-type electrode and an n-type electrode. The first pin 121 is welded to the p-type electrode, and the second pin 122 is welded to the n-type electrode.

[0044] It should be noted that the p-type electrode is formed by doping trivalent impurity atoms into an intrinsic semiconductor. Since the outermost layer of trivalent impurity atoms has only three electrons, when forming a covalent bond with the tetravalent intrinsic semiconductor atoms, holes will be generated, making the p-type electrode exhibit the characteristics of hole conduction. The n-type electrode is formed by doping pentavalent impurity atoms into an intrinsic semiconductor. Since the outermost layer of pentavalent impurity atoms has five electrons, when forming a covalent bond with the tetravalent intrinsic semiconductor atoms, there will be an extra electron, that is, a free electron, making the n-type semiconductor mainly carry current with electrons. Based on the different structures of the above p-type electrode and n-type electrode, the p-type electrode can be used as the anode and welded to the first pin 121 of the socket 1, and the n-type electrode can be used as the cathode and welded to the second pin 122 of the socket 1.

[0045] As Figure 2 shown, in some embodiments, the socket 1 further includes a ground wire 123. When the metal shell of the infrared photodetector is electrified due to an internal circuit fault, the ground wire 123 will quickly conduct the current into the ground, keeping the potential of the metal shell at zero potential, thus ensuring the safety of the user. In addition, the ground wire 123 can also provide a low-impedance return path for high-frequency signals in the circuit, reducing the mutual interference between signals. Furthermore, the ground wire 123 can also be used as a potential reference point to provide a reference for other potentials and ensure the accuracy of signal processing.

[0046] In some embodiments, the interior of the packaging structure formed by the socket 1 and the metal cap 2 is vacuum or inert gas. There are various gas molecules in the atmospheric environment, such as oxygen, carbon dioxide, and water vapor, etc. These gas molecules will absorb the infrared radiation in the incident light. If there are these gases that can absorb infrared radiation inside the infrared photodetector based on the metalens, it will cause partial loss of infrared signals, reducing the sensitivity and detection distance of the detector.

[0047] Furthermore, the presence of gas molecules in the atmospheric environment will scatter the infrared radiation and change the propagation direction of the infrared light. Therefore, the infrared radiation that should originally reach the detector chip 3 directly may be scattered in other directions, resulting in a decrease in the intensity of the infrared signal received by the detector chip 3, thereby affecting the detection effect.

[0048] In addition, after the hyperlens-based infrared photodetector absorbs infrared radiation, the absorbed energy needs to be converted into detectable signals such as electrical signals. If there are a large number of gas molecules in the atmosphere inside the detector, when the detector chip 3 absorbs infrared radiation to generate carriers, the gas molecules will exchange heat with the detector chip 3, thereby affecting the response speed of the infrared photodetector. A vacuum or inert gas environment can reduce this heat exchange, improve the response speed of the infrared photodetector, and is conducive to the detection and processing of rapidly changing infrared signals.

[0049] For the above reasons, setting the inside of the hyperlens-based infrared photodetector to a vacuum or inert gas can reduce the occurrence of these problems. Exemplarily, the inert gas can be helium, neon, argon, krypton, xenon, and radon. The present application does not limit the types of inert gases.

[0050] In some embodiments, the hyperlens is configured to regulate the optical phase of the incident light so that the optical phase of the incident light changes after passing through the hyperlens 21 by an amplitude of phase change; the arrangement distance of the hyperlens units 2121 is less than or equal to , and the arrangement distance is used to characterize the distance between two adjacent hyperlens units 2121.

[0051] As Figure 3 shown, in a two-dimensional plane, the hyperlens units 2121 are arranged at the same periodic interval in the horizontal and vertical directions to form a square grid structure. By setting the size, shape, and arrangement period of the hyperlens units 2121, the optical phase of the incident light changes by an amplitude of phase change after passing through the hyperlens 21.

[0052] Figure 4 This is another schematic diagram of the arrangement structure of the hyperlens unit provided by the embodiment of the present application. As Figure 4 shown, in a two-dimensional plane, the hyperlens units 2121 are arranged in a regular hexagonal arrangement. The hyperlens array 212 arranged in a regular hexagonal array has a higher filling efficiency, can arrange more hyperlens units 2121 in the same area, and the gap between the hyperlens units 2121 is smaller, which is more conducive to the uniform propagation and regulation of incident light.

[0053] In some embodiments, the hyperlens unit 2121 is a cylindrical structure, the bottom diameter of the hyperlens unit 2121 is equal to the arrangement distance of the hyperlens unit 2121; the height of the hyperlens unit 2121 is 0.4 to 0.6 times the preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip 3.

[0054] The cylindrical-structured metalens unit 2121 can enhance the scattering and diffraction of incident light. By changing the height and radius of the metalens unit 2121, the modulation of incident light can be achieved. In addition, due to the symmetry of the cylindrical structure, the effect of the metalens unit 2121 on incident light in different directions has a certain regularity. The transmittance of the incident light is increased, and the interference effect of the reflected light is suppressed.

[0055] Exemplarily, the arrangement distance of the metalens units 2121 is equal to , the bottom diameter of the metalens unit 2121 is equal to , and the height of the metalens unit 2121 is 0.4 times the preset wavelength. Furthermore, after the incident light passes through the metalens 21, a phase change of the light phase amplitude occurs according to the preset requirements.

[0056] It should be noted that the preset wavelength is the peak wavelength of the detector chip 3. Since incident light of different wavelengths has different energies, when the incident light irradiates the detector chip 3, the detector chip 3 will absorb the photon energy and generate corresponding electrical signals. At a certain specific wavelength, the detector chip 3 can most effectively convert the optical signal into an electrical signal. At this time, the responsivity of the detector chip 3 reaches the peak, and this wavelength is the peak wavelength. That is to say, the peak wavelength is used to characterize the wavelength of the light corresponding to the maximum responsivity of the detector chip 3 to the incident light.

[0057] Exemplarily, the preset wavelength of the detector chip 3 is 1310 nm, and the height of the metalens unit 2121 is 524 nm.

[0058] In some embodiments, the metalens unit 2121 is a waist structure, Figure 5 which is a schematic diagram of the waist structure of the metalens unit provided by the embodiment of the present application. As Figure 5 shown, the metalens unit 2121 is provided with a groove in a ring shape. The groove wall of the groove includes a vertical section 21211, a first transition section 21212, and a second transition section 21213. The included angle between the vertical section 21211 and the first transition section 21212 is a first preset angle, and the included angle between the vertical section 21211 and the second transition section 21213 is a second preset angle. The first preset angle is greater than or equal to the second preset angle, and the length of the first transition section 21212 is less than or equal to the length of the second transition section 21213; the height of the metalens unit 2121 is 0.4 to 0.6 times the preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip 3; the height of the vertical section 21211 is 0.2 to 0.3 times the height of the metalens unit 2121.

[0059] The first preset angle between the vertical segment 21211 and the first transition segment 21212 is greater than or equal to the second preset angle between the vertical segment 21211 and the second transition segment 21213, so that the top width of the waist-shaped structure's superlens unit 2121 is equal to or narrower than the bottom width.

[0060] By providing a groove around the superlens unit 2121, the superlens unit 2121 has a waist-shaped structure, that is, in the axial direction perpendicular to the first surface of the base 1, the size of the middle part of the superlens unit 2121 is smaller than the sizes of the two side parts.

[0061] The waist-shaped structure's superlens unit 2121 can enhance the focusing ability of the superlens 21. By designing the size of the waist-shaped structure's superlens unit 2121, when regulating the incident light rays, it can produce a stronger converging effect on the light rays and perform a more delicate modulation on the phase of the incident light. Then, after the incident light passes through the superlens 21, the phase of the light changes in amplitude according to the preset requirements, improving the transmittance of the incident light and suppressing the interference effect of the reflected light.

[0062] Exemplarily, the preset wavelength of the detector chip 3 is 1310 nm, the height of the superlens unit 2121 is 524 nm, and the height of the vertical segment 21211 is 105 nm.

[0063] In some embodiments, the waist-shaped structure's superlens unit 2121 is axially symmetric about a first axis perpendicular to the surface where the superlens substrate 211 is located. The bottom surface of the waist-shaped structure's superlens unit 2121 is circular, and the bottom diameter is equal to the arrangement distance of the superlens units 2121.

[0064] Due to the symmetry of the waist-shaped structure's superlens unit 2121, the effects of the superlens unit 2121 on the incident light in different directions have a certain regularity, thereby achieving a more delicate modulation of the phase of the incident light, and achieving the effects of improving the transmittance of the incident light and suppressing the interference effect of the reflected light.

[0065] In some embodiments, the detector chip 3 is stacked with a substrate layer, a p-type layer, a p-type electrode, an absorption layer, an n-type layer, and an n-type electrode from top to bottom in sequence.

[0066] In some other embodiments, the detector chip 3 is stacked with a p-type electrode, a substrate layer, a p-type layer, an absorption layer, an n-type layer, and an n-type electrode from top to bottom in sequence.

[0067] Among them, the substrate layer can be a substrate structure made of gallium antimonide (GaSb), that is, a GaSb substrate layer. The GaSb substrate layer has the ability to absorb infrared light in the mid-infrared band, which can enhance the absorption efficiency of the detector for infrared light, improve the sensitivity and responsivity of the detector chip 3. Moreover, the GaSb substrate layer has a good lattice matching degree with the epitaxially grown material, which can reduce defects and dislocations and improve the overall performance of the detector chip 3. The substrate layer can also provide physical support for other functional layers to ensure the structural stability of the detector chip 3.

[0068] The p-type layer and the n-type layer jointly form a PN junction. Among them, the p-type layer is used to store holes, and the n-type layer provides carriers opposite to those of the p-type layer, that is, electrons. When incident light enters the detector chip 3, the electrons in the n-type layer and the holes in the p-type layer form a built-in electric field. Thereby, electron-hole pairs are generated in the detector chip 3. The holes in the p-type layer participate in conduction and form a current with the electrons generated in the n-type layer, thus realizing the electrical conversion of the optical signal.

[0069] The PN junction has unidirectional conductivity. The p-type layer is connected to the positive electrode, and the n-type layer is connected to the negative electrode. When the PN junction is forward-biased, the external electric field is opposite to the direction of the built-in electric field, the built-in electric field is weakened, and the diffusion motion is enhanced, forming a large forward current. The PN junction presents a low-resistance state and is in the on state. When the PN junction is reverse-biased, the external electric field is in the same direction as the built-in electric field, the built-in electric field is enhanced, the diffusion motion is suppressed, and only the drift motion of a small number of carriers forms a very small reverse current. The PN junction presents a high-resistance state and is in the off state.

[0070] The structures and functions of the p-type electrode and the n-type electrode have been described in the introduction of the chip electrodes of the detector chip 3, and will not be elaborated here.

[0071] The absorption layer is used to absorb photons in the mid-infrared band of the incident light. When the detector chip 3 absorbs photons, electron-hole pairs are generated in the absorption layer through the photoelectric effect, thereby providing a basis for generating an electrical signal for the detector chip 3.

[0072] As can be seen from the above technical solutions, by using the infrared photodetector based on a metalens provided in the embodiments of the present application, when an infrared radiation signal enters the detector chip through the metalens at the top of the metal cap, the infrared radiation signal can be converted into an electrical signal, thereby realizing the detection of the infrared photodetector. When the infrared radiation signal enters the metalens, the metalens units periodically arranged on the surface of the metalens can reduce the reflection loss of the wide-spectrum signal in the infrared radiation signal, improve the transmittance of the incident light of the infrared photodetector, and suppress the interference effect of the reflected light, thereby improving the detection rate of the infrared photodetector.

[0073] Corresponding to the embodiments of the aforementioned infrared photodetector based on a metalens, the present application also provides embodiments of a method for manufacturing an infrared photodetector based on a metalens.

[0074] Figure 6 The flowchart of the method for manufacturing an infrared photodetector based on a metalens provided by the embodiments of the present application is as Figure 6 shown. The method for manufacturing an infrared photodetector based on a metalens includes the following steps.

[0075] Step S1: Provide a header, a metalens, a metal package, and a detector chip.

[0076] In some embodiments, the header includes pins for connecting the header and the detector chip. Before connecting the detector chip to the header, the header can be cleaned successively with trichloroethylene, acetone, and ethanol, and then sprayed with deionized water and rinsed for a preset time, and finally dried to obtain a cleaned header. The preset time can be 5 minutes.

[0077] It should be understood that if there are impurities on the surface of the header, it will affect the bonding effect between the metal package and the header, as well as between the detector chip and the header, resulting in insecure sealing. By cleaning the header, the impurities on the surface of the header can be removed, providing a good attachment surface for the detector chip and the metal package. In addition, the header is prone to oxidation in the air, forming an oxide layer, which will change the electrical and optical properties of the header surface. By cleaning the header, the oxide layer can be removed, improving the conductivity and optical performance of the header.

[0078] Step S2: Solder the detector chip to the pins and apply glue to the bottom of the detector chip.

[0079] In some embodiments, the detector chip can be soldered to the pins of the header using gold wires.

[0080] Exemplarily, solder the p-type electrode of the detector chip to the first pin of the header and solder the n-type electrode of the detector chip to the second pin of the header.

[0081] Furthermore, apply glue to the bottom of the detector chip to fix the detector chip in the installation area of the header, preventing the detector chip from shifting or falling off due to vibration, impact, etc., and improving the bonding effect between the detector chip and the header. The glue at the bottom of the detector chip can be non-conductive glue, which can form an insulating layer between the contact surfaces of the detector chip and the header, thereby effectively isolating the current and preventing short circuits between the detector chip and the header.

[0082] After fixing the detector chip on the mounting area of the header using non-conductive adhesive, the detector chip can also be baked at a preset temperature to improve the adhesion of the non-conductive adhesive and enhance the bonding effect. The preset temperature can be from 70 degrees Celsius to 90 degrees Celsius.

[0083] Step S3: Etch a meta-lens substrate and a meta-lens array on the meta-lens.

[0084] In some embodiments, the meta-lens array includes multiple meta-lens units, and the multiple meta-lens units are periodically arranged above the meta-lens substrate. Lithography technology can be used to etch a meta-lens substrate and a meta-lens array on the meta-lens. The meta-lens array includes multiple periodically arranged meta-lens units. The lithography technology can be electron beam lithography, ion beam lithography, interference lithography, etc. The present application does not specifically limit the method for etching the meta-lens units.

[0085] Step S4: Weld the meta-lens to the metal housing.

[0086] In some embodiments, the etched meta-lens is welded to the metal housing to obtain a metal cap, where the top of the metal cap is the meta-lens and the side wall is the metal housing.

[0087] Step S5: Under a vacuum environment or an inert gas environment, weld the metal cap above the header so that the detector chip is encapsulated between the header and the metal cap.

[0088] Exemplarily, the metal cap and the header with the detector chip fixed thereon are placed in the chamber of a high-vacuum pumping system. The vacuum pump is turned on. When the preset vacuum degree is reached in the chamber, the metal cap is welded above the header, and then a packaged infrared photodetector based on a meta-lens is obtained.

[0089] Exemplarily, the metal cap and the header with the detector chip fixed thereon are placed in a chamber under a nitrogen environment, and the metal cap is welded above the header to obtain a packaged infrared photodetector based on a meta-lens.

[0090] It can be understood that for the beneficial effects that can be achieved by the above-provided manufacturing method of the infrared photodetector based on a meta-lens, reference can be made to the beneficial effects in the infrared photodetector based on a meta-lens and any of its optional embodiments, which will not be elaborated here.

[0091] It should be noted that those skilled in the art will easily think of other implementation schemes of the present application after considering the specification and practicing the application disclosed herein. The present application aims to cover any variations, uses, or adaptive changes of the present application, and these variations, uses, or adaptive changes follow the general principles of the present application and include the common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only regarded as exemplary, and the true scope of the present application is pointed out by the claims.

[0092] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. An infrared photodetector based on a superlens, characterized in that: include: A tube base (1), a metal tube cap (2), and a detector chip (3) packaged between the tube base (1) and the metal tube cap (2); The tube seat (1) comprises a base plate (11) and pins (12), wherein the pins (12) are arranged on a first surface of the base plate (11), and the first surface is a surface of the tube seat (1) facing the metal tube cap (2); The detector chip (3) is an infrared detector unit device, the detector chip (3) is fixed to the first surface of the tube holder (1) based on a non-conductive adhesive, the detector chip (3) comprises a chip electrode, and the chip electrode is welded to the pin (12); The metal tube cap (2) is a columnar structure with an open bottom, the top of the metal tube cap (2) is a super lens (21), the side wall is a metal tube shell (22), and the bottom of the metal tube shell (22) is fixed to the first surface of the tube base (1) to form a fully enclosed packaging structure; The superlens (21) comprises a superlens substrate (211) and a superlens array (212), wherein the superlens substrate is used to support the superlens array (212), and the superlens array (212) comprises a plurality of superlens units (2121), and the plurality of superlens units (2121) are periodically arranged above the superlens substrate (211).

2. The infrared photodetector based on superlens according to claim 1, characterized in that: The pin (12) comprises a first pin (121) and a second pin (122); the chip electrode comprises a p-type electrode and an n-type electrode; the first pin (121) is welded to the p-type electrode, and the second pin (122) is welded to the n-type electrode.

3. The infrared photodetector based on superlens according to claim 1, characterized in that: The interior of the packaging structure formed by the tube seat (1) and the metal tube cap (2) is a vacuum or an inert gas.

4. The infrared photodetector based on a superlens according to claim 1, characterized in that: The super lens (21) is configured to regulate the optical phase of the incident light so that the optical phase of the incident light after passing through the super lens (21) changes. Phase change of amplitude; The arrangement distance of the super lens units (2121) is less than or equal to The arrangement distance is used to characterize the distance between two adjacent super lens units (2121).

5. The infrared photodetector based on superlens according to claim 4, characterized in that: The super lens unit (2121) is a cylindrical structure, and the bottom diameter of the super lens unit (2121) is equal to the arrangement distance of the super lens unit (2121); The height of the super lens unit (2121) is 0.4 to 0.6 times a preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip (3).

6. The infrared photodetector based on superlens according to claim 4, characterized in that: The super lens unit (2121) is provided with a groove, the groove wall of the groove comprises a vertical section (21211), a first transition section (21212) and a second transition section (21213), the angle between the vertical section (21211) and the first transition section (21212) is a first preset angle, the angle between the vertical section (21211) and the second transition section (21213) is a second preset angle, the first preset angle is greater than or equal to the second preset angle, and the length of the first transition section (21212) is less than or equal to the length of the second transition section (21213); The height of the super lens unit (2121) is 0.4 to 0.6 times a preset wavelength, and the preset wavelength is used to characterize the peak wavelength of the detector chip (3); The height of the vertical segment (21211) is 0.2 to 0.3 times the height of the super lens unit (2121).

7. The infrared photodetector based on superlens according to claim 6, characterized in that: The super lens unit (2121) is symmetrical based on a first axis, the first axis is perpendicular to the surface on which the super lens substrate (211) is located, the bottom surface of the super lens unit (2121) is circular, and the bottom surface diameter of the super lens unit (2121) is equal to the arrangement distance of the super lens unit (2121).

8. The infrared photodetector based on superlens according to claim 2, characterized in that: The detector chip (3) comprises a substrate layer, a p-type layer, a p-type electrode, an absorption layer, an n-type layer and an n-type electrode which are stacked in sequence from top to bottom.

9. The infrared photodetector based on superlens according to claim 2, characterized in that: The detector chip (3) comprises a p-type electrode, a substrate layer, a p-type layer, an absorption layer, an n-type layer and an n-type electrode which are sequentially stacked from top to bottom.

10. A method for manufacturing an infrared photodetector based on a superlens, characterized in that: include: Providing a tube holder, a super lens, a metal tube shell and a detector chip, wherein the tube holder includes pins; Welding the detector chip to the pins and applying glue to the bottom of the detector chip to fix the detector chip to the mounting area of ​​the tube holder; Etching a superlens substrate and a superlens array on the superlens, wherein the superlens array includes a plurality of superlens units, and the plurality of superlens units are periodically arranged above the superlens substrate; Welding the superlens to the metal tube shell to obtain a metal tube cap, wherein the top of the metal tube cap is the superlens and the side wall is the metal tube shell; In a vacuum environment or an inert gas environment, the metal tube cap is welded onto the tube base, so that the detector chip is packaged between the tube base and the metal tube cap.

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