Medium-wave infrared integrated polarization detector and preparation method thereof

Abstract

The invention provides a medium-wave infrared integrated polarization detector and a preparation method, the medium-wave infrared integrated polarization detector comprises a plurality of polarization gratings which are arranged in a periodic array, a dielectric film layer and a medium-wave infrared detection chip which are arranged in sequence, and the medium-wave infrared detection chip is provided with a plurality of pn junction regions which are arranged in a periodic array. The pn junction regions and the polarization gratings are arranged in a one-to-one correspondence manner, the medium-wave infrared detection chip is provided with a plurality of isolation grooves, the isolation grooves are correspondingly arranged between two adjacent polarization gratings, and the isolation grooves are filled with isolation pieces. By arranging the isolation piece in the medium-wave infrared detection chip, polarized light crosstalk of two adjacent polarization gratings is inhibited, and the extinction ratio of the medium-wave infrared integrated polarization detector is improved. According to the preparation method disclosed by the invention, the nanoscale polarization grating is directly processed on the dielectric film layer by adopting a nanoimprint technology, so that the processing efficiency can be improved, and the processing cost can be reduced.

Description

Technical Field

[0001] Embodiments of the present disclosure belong to the technical field of infrared detectors, and particularly relate to a mid-wave infrared integrated polarization detector and a preparation method thereof. Background Art

[0002] Infrared polarization detection technology can detect polarization information in addition to light intensity information, including degree of polarization and polarization angle information, and uses the polarization characteristic differences between the target and the background to identify the target. Compared with intensity and wavelength detection, polarization imaging has stronger adaptability to complex environments and camouflage scenes such as underwater and foggy days. In the case where the effective information of the target is absorbed or scattered, polarization detection can effectively suppress background noise and interference signals and improve the accuracy of target detection. Mid-wave infrared polarization detection has important application values in military reconnaissance, industrial detection and other fields due to its high sensitivity and strong anti-interference ability.

[0003] Traditional polarization imaging detection mainly includes time-sharing detection, amplitude-division detection, aperture-division detection and focal-plane-division detection. Among them, focal-plane-division detection can obtain information of multiple polarization components at the same time, and the focal-plane-division polarization structure is easy to be integrated with the detector, having the advantages of high integration and high stability. Literature [1] Li Junyu, Yi Fei, etc., A dual-color polarization uncooled infrared detector and its manufacturing method, CN111947789B, 2021. The literature discloses a structure of an integrated polarization infrared detector, in which a grating and a detector pixel are directly integrated to form a super-pixel structure to realize polarization detection. Literature [2] Junyang Zhang, Zhendong Gao, etc., "Opto-electrical and polarization performance of a mesa-structured InGaAs PIN detector integrated with subwavelength aluminum gratings", Optics Letters, 47(30), 2022: 6173. (Zhang Junyang, Gao Zhendong, etc., "Opto-electrical and polarization performance of a mesa-structured InGaAs PIN detector integrated with subwavelength aluminum gratings", Optics Letters, Volume 47, Issue 30, 2022, Page 6173), the literature gives an integrated polarization detector structure similar to that in Literature [1], directly integrating an Al grating on an InGaAs detector pixel, and processing the polarization grating by the EBL process, achieving an extinction ratio of 18:1 at a working wavelength of 1550 nm.

[0004] Directly fabricating a polarization micro-nano grating on a detector pixel has good stability and high alignment accuracy. By reducing the distance between the polarization grating and the detector's photosensitive pixel unit, optical crosstalk can be decreased and the extinction ratio can be improved. This is currently a research hotspot for integrated polarization detectors and has been widely reported in the visible and near-infrared bands. However, specifically for mid-wave infrared polarization detectors, especially cryogenic detectors, due to their high detection sensitivity, the influence of crosstalk between adjacent polarization pixels is significant, and the following problems need to be urgently solved: First, due to the diffraction effect of the polarization grating pixels, the crosstalk between adjacent pixels is large, which limits the extinction ratio of the integrated polarization detector. Second, to obtain a higher extinction ratio, it is necessary to further reduce the period of the polarization grating, which increases the difficulty of process processing. Currently, electron beam lithography (EBL) is usually used for the processing of fine polarization gratings, resulting in extremely low processing efficiency and high costs, which limits the wide application of high-performance integrated polarization detectors. Summary of the Invention

[0005] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a mid-wave infrared integrated polarization detector and a preparation method thereof.

[0006] The first aspect of the present disclosure provides a mid-wave infrared integrated polarization detector, which includes a plurality of polarization gratings arranged in a periodic array, a dielectric film layer, and a mid-wave infrared detection chip arranged in sequence. The mid-wave infrared detection chip has a plurality of pn junction regions arranged in a periodic array, and the pn junction regions are arranged in one-to-one correspondence with the polarization gratings. The mid-wave infrared detection chip has a plurality of isolation grooves, and the isolation grooves are correspondingly arranged between two adjacent polarization gratings, and an isolation member is filled in the isolation grooves.

[0007] In some embodiments of the present disclosure, the isolation grooves extend from one side of the mid-wave infrared detection chip close to the dielectric film layer to the side away from the dielectric film layer.

[0008] In some embodiments of the present disclosure, the isolation member is in contact with the dielectric film layer.

[0009] In some embodiments of the present disclosure, the depth of the isolation grooves is 5 μm, and the width of the isolation grooves is 4 μm.

[0010] In some embodiments of the present disclosure, the material of the isolation member is zinc sulfide.

[0011] In some embodiments of the present disclosure, four adjacent polarization gratings form a super pixel, and the directions of the four polarization gratings of the super pixel are different.

[0012] In some embodiments of the present disclosure, the polarization grating includes 62 grating units arranged in a periodic array. The period of the grating unit is 400 nm, the line width of the grating unit is 200 nm, the size of the polarization grating is 25 μm × 25 μm, and the distance between two adjacent polarization gratings is 30 μm.

[0013] In some embodiments of the present disclosure, the mid-wave infrared detection chip further has a plurality of pn junction regions arranged in a periodic array. The pn junction regions extend from the side of the mid-wave infrared chip facing away from the dielectric film layer towards the side close to the dielectric film layer. Each pn junction region is arranged corresponding to one polarization grating, and the spacer is located between two adjacent pn junction regions.

[0014] In some embodiments of the present disclosure, the material of the dielectric film layer is zinc sulfide, the material of the polarization grating is aluminum, and the material of the mid-wave infrared detection chip is mercury cadmium telluride.

[0015] A second aspect of the present disclosure provides a method for manufacturing a mid-wave infrared integrated polarization detector for manufacturing the mid-wave infrared integrated polarization detector according to any one of the above embodiments. The manufacturing method includes: Manufacturing a mid-wave infrared detection chip containing a plurality of pn junction regions; Manufacturing a plurality of isolation grooves on the side of the mid-wave infrared detection chip facing away from the pn junction regions, and filling zinc sulfide in the isolation grooves to form a spacer; Manufacturing a dielectric film layer on the side of the mid-wave infrared detection chip facing away from the pn junction regions; Using nanoimprint technology to manufacture a polarization grating on the side of the dielectric film layer facing away from the mid-wave infrared detection chip; Flip-chip bonding the side of the pn junction region of the mid-wave infrared detection chip to a readout circuit to form a mid-wave infrared integrated detector.

[0016] The mid-wave infrared integrated polarization detector and preparation method according to the embodiments of the present disclosure include a plurality of polarization gratings arranged in a periodic array, a dielectric film layer, and a mid-wave infrared detection chip arranged in sequence. The polarization gratings are used to receive infrared incident light to obtain the light intensity signals of different polarization directions in the infrared incident light and emit them. The dielectric film layer arranged between the polarization gratings and the mid-wave infrared detection chip is used to make more infrared incident light passing through the polarization gratings reach the mid-wave infrared detection chip. The mid-wave infrared detection chip receives the light intensity signal passing through the dielectric film layer, and converts the light intensity signal into a current signal and outputs it. The plurality of polarization gratings arranged in a periodic array are arranged in one-to-one correspondence with a plurality of pn junction regions arranged in a periodic array. The mid-wave infrared detection chip has a plurality of isolation grooves, and the isolation grooves are correspondingly arranged between two adjacent polarization gratings, and each isolation groove is filled with an isolation member. By arranging the isolation member in the mid-wave infrared detection chip, the polarization light crosstalk between two adjacent polarization gratings is suppressed, and the extinction ratio of the mid-wave infrared integrated polarization detector is improved. The preparation method of this embodiment uses nanoimprint technology to directly process nano-scale polarization gratings on the dielectric film layer, which can improve the processing efficiency and reduce the processing cost. Description of the Drawings

[0017] Figure 1 Schematic structural diagram of the mid-wave infrared integrated polarization detector according to the embodiments of the present disclosure; Figure 2 is Figure 1 Cross-sectional view of the mid-wave infrared integrated polarization detector shown; Figure 3 is Figure 1 Top view of the mid-wave infrared integrated polarization detector shown; Figure 4 is Figure 1 Partial cross-sectional view of the mid-wave infrared integrated polarization detector shown; Figure 5 is Figure 1 Comparison diagram of the transmittance curves of single-pixel TM light of the mid-wave infrared integrated polarization detector shown and the mid-wave infrared integrated polarization detector without an isolation member; Figure 6 is Figure 1 Comparison diagram of the transmittance curves of single-pixel TE light of the mid-wave infrared integrated polarization detector shown and the mid-wave infrared integrated polarization detector without an isolation member; Figure 7 is Figure 1 Comparison diagram of the extinction ratios of single pixels of the mid-wave infrared integrated polarization detector shown and the mid-wave infrared integrated polarization detector without an isolation member; Figure 8 Flowchart of the preparation method of the mid-wave infrared integrated polarization detector according to the embodiments of the present disclosure; Figure 9Flowchart showing the specific steps of the preparation method of the mid-wave infrared integrated polarization detector according to the embodiments of the present disclosure.

[0018] The reference numerals in the drawings are defined as follows: 100, polarization grating; 100A, metal thin film; 101, second adhesive layer; 200, dielectric film layer; 300, mid-wave infrared detection chip; 301, spacer; 301A, deep groove; 301B, zinc sulfide layer; 302, pn junction region; 303, first adhesive layer; 400, readout circuit; 500, indium pillar; 600, infrared incident light. Detailed implementation manners

[0019] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0020] It should be understood that the terms used herein are for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless otherwise clearly specified in the context, the singular forms "a", "an" and "the" as used herein may also include the plural forms. The terms "comprising", "including", "containing" and "having" are inclusive and thus specify the presence of the stated features, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the order of performance is explicitly stated. It should also be understood that additional or alternative steps may be used.

[0021] Although the terms first, second, third, etc. may be used herein to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer or section from another region, layer or section. Unless explicitly stated in the context, terms such as "first" and "second" and other numerical terms used herein do not imply an order or sequence. Thus, the first element, component, region, layer or section discussed below may be referred to as the second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0022] For ease of description, spatial relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure with respect to another element or feature. These relative relationship terms are, for example, "inner", "outer", "inner side", "outer side", "below", "beneath", "above", "over", etc. Such spatial relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientations depicted in the figure. For example, if the device in the figure is flipped, an element described as "below" or "beneath" another element or feature will then be oriented as "above" or "over" the other element or feature. Thus, the exemplary term "below" can include both upward and downward orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used in the text are interpreted accordingly.

[0023] As Figures 1 to 4 shown, a first aspect of the present disclosure provides a mid-wave infrared integrated polarization detector. The mid-wave infrared integrated polarization detector includes a plurality of polarization gratings 100 arranged in a periodic array, a dielectric film layer 200, and a mid-wave infrared detection chip 300 disposed in sequence. The mid-wave infrared detection chip 300 has a plurality of pn junction regions 302 arranged in a periodic array. The pn junction regions 302 are arranged in one-to-one correspondence with the polarization gratings 100. The mid-wave infrared detection chip 300 has a plurality of isolation grooves, and the isolation grooves are correspondingly disposed between two adjacent polarization gratings 100. The isolation grooves are filled with isolation members 301.

[0024] According to the mid-wave infrared integrated polarization detector of the present disclosure, it includes a plurality of polarization gratings 100 arranged in a periodic array, a dielectric film layer 200, and a mid-wave infrared detection chip 300 disposed in sequence. The polarization grating 100 is configured to receive infrared incident light 600 to obtain light intensity signals of different polarization directions in the infrared incident light 600 and emit them. The dielectric film layer 200 disposed between the polarization grating 100 and the mid-wave infrared detection chip 300 is configured to allow more infrared incident light 600 passing through the polarization grating 100 to reach the mid-wave infrared detection chip 300. The mid-wave infrared detection chip 300 receives the light intensity signal transmitted through the dielectric film layer 200, and converts the light intensity signal into a current signal and outputs it. The plurality of polarization gratings 100 arranged in a periodic array are arranged in one-to-one correspondence with the plurality of pn junction regions 302 arranged in a periodic array. The mid-wave infrared detection chip 300 has a plurality of isolation grooves, and the isolation grooves are correspondingly arranged between two adjacent polarization gratings 100. Each isolation groove is filled with an isolation member 301. By providing the isolation member 301 in the mid-wave infrared detection chip 300, the polarization light crosstalk between two adjacent polarization gratings 100 is suppressed, and the extinction ratio of the mid-wave infrared integrated polarization detector is improved.

[0025] In some embodiments of the present disclosure, a plurality of polarization gratings 100 are arranged in a periodic array. Among them, four adjacent polarization gratings 100 form a superpixel, and the directions of the four polarization gratings 100 in one superpixel are different. Specifically, the four polarization gratings 100 of the superpixel can be polarization gratings 100 in the four directions of 0°, 45°, 90°, and 135° respectively. The four polarization gratings 100 of the superpixel can also be polarization gratings 100 in other four directions.

[0026] In some embodiments of the present disclosure, the polarization grating 100 includes 62 grating units arranged in a periodic array. The period of the grating unit is 400 nm, the line width of the grating unit is 200 nm, the size of the polarization grating 100 is 25 μm × 25 μm, and the center-to-center distance between two adjacent polarization gratings 100 is 30 μm. Specifically, the material of the polarization grating 100 is aluminum. The aluminum material polarization grating 100 has the characteristics of wide-spectrum response, high environmental stability, light weight, and low cost.

[0027] In some embodiments of the present disclosure, the mid-wave infrared detection chip 300 also has a plurality of pn junction regions 302 arranged in a periodic array. The pn junction regions 302 extend from the side of the mid-wave infrared chip facing away from the dielectric film layer 200 towards the side close to the dielectric film layer 200, and each pn junction region 302 is arranged corresponding to one polarization grating 100. The projection of the spacer 301 on the bottom surface of the mid-wave infrared detection chip 300 facing away from the dielectric film layer 200 is located between two adjacent pn junction regions 302. Specifically, the material of the mid-wave infrared detection chip 300 is mercury cadmium telluride. Mercury cadmium telluride (HgCdTe) has the advantages of high sensitivity, wide-spectrum tunability, fast response, and radiation resistance.

[0028] In some embodiments of the present disclosure, the isolation groove extends from the side of the mid-wave infrared detection chip 300 close to the dielectric film layer 200 towards the side away from the dielectric film layer 200, that is, the isolation groove extends along the thickness direction of the mid-wave infrared detection chip 300, so that the spacer 301 extends from the side of the mid-wave infrared detection chip 300 close to the dielectric film layer 200 towards the side of the pn junction region 302 of the mid-wave infrared detection chip 300. The spacer 301 extends along the thickness direction of the mid-wave infrared detection chip 300, suppressing the crosstalk of the polarized light of two adjacent polarization gratings 100 in the mid-wave infrared detection chip 300.

[0029] Specifically, the isolation groove extends from the surface of the mid-wave infrared detection chip 300 in contact with the dielectric film layer 200 to the surface of the mid-wave infrared detection chip 300 facing away from the dielectric film layer 200. That is, one end of the isolator 301 is in contact with the dielectric film layer 200, and the other end of the isolator 301 extends into the interior of the mid-wave infrared detection chip 300. Specifically, the material of the isolator 301 is the same as that of the dielectric film layer 200, both being zinc sulfide. The isolator 301 made of zinc sulfide has the characteristics of wide-band light transmittance, high refractive index, and excellent electrical isolation.

[0030] In some embodiments of the present disclosure, the depth of the isolation groove is the dimension of the isolation groove along the thickness direction of the mid-wave infrared detection chip 300. Specifically, the depth of the isolation groove is 5 μm. The width of the isolation groove refers to the dimension of the isolation groove along the direction from the nearest polarization grating 100 on one side to the nearest polarization grating 100 on the other side. Specifically, the width of the isolation groove is 4 μm. The length of the isolation groove is greater than or equal to the side length of the polarization grating 100.

[0031] As Figure 5 shown, the transmittance of the single-pixel TM light changes little before and after adding the isolator 301, and there is a slight increase after adding the isolator 301. As Figure 6 shown, the transmittance of the single-pixel TE light changes significantly after adding the isolator 301. After adding the isolator 301, the transmittance of the TE light decreases. Combining the changes in the transmittance of the TM light and the TE light, as Figure 7 shown, after adding the isolator 301, the extinction ratio has a significant increase compared to before adding the isolator 301. It can be seen that adding the isolator 301 to the mid-wave infrared detection chip 300 can improve the extinction ratio.

[0032] As Figure 8 、 Figure 9 shown, a second aspect of the present disclosure proposes a method for manufacturing a mid-wave infrared integrated polarization detector for manufacturing the mid-wave infrared integrated polarization detector according to any one of the above embodiments. The manufacturing method includes: S100: Prepare a mid-wave infrared detection chip 300 containing multiple pn junction regions 302; S200: Prepare a plurality of isolation grooves on the side of the mid-wave infrared detection chip 300 facing away from the pn junction region 302, and fill zinc sulfide in the isolation grooves to form an isolator 301; S300: Prepare a dielectric film layer 200 on the side of the mid-wave infrared detection chip 300 facing away from the pn junction region 302; S400: Use nanoimprint technology to prepare a polarization grating 100 on the side of the dielectric film layer 200 facing away from the mid-wave infrared detection chip 300; S500: Flip-chip bond one side of the pn junction region 302 of the mid-wave infrared detection chip 300 to the readout circuit 400 to form a mid-wave infrared integrated detector.

[0033] According to the preparation method of the mid-wave infrared integrated polarization detector of the present disclosure, first prepare a mid-wave infrared detection chip 300 containing multiple pn junction regions 302, and prepare multiple isolation grooves on the side of the mid-wave infrared detection chip 300 facing away from the pn junction region 302, so as to fill zinc sulfide in the isolation grooves to form an isolation member 301 made of zinc sulfide. Then, prepare a dielectric film layer 200 on the side of the mid-wave infrared detection chip facing away from the pn junction region 302. Next, use nanoimprint technology to prepare a polarization grating 100 on the side of the dielectric film layer 200 facing away from the mid-wave infrared detection chip 300. Finally, flip-chip bond one side of the pn junction region 302 of the mid-wave infrared detection chip 300 to the readout circuit 400 to form a mid-wave infrared integrated detector. The preparation method of this embodiment uses nanoimprint technology to directly process a nano-scale polarization grating 100 on the dielectric film layer 200, which can improve the processing efficiency and reduce the processing cost. In addition, the isolation member 301 is provided in the mid-wave infrared detection chip 300 prepared by the preparation method of this embodiment, which can suppress the polarization light crosstalk between two adjacent polarization gratings 100 and improve the extinction ratio of the mid-wave infrared integrated polarization detector.

[0034] The specific steps of the preparation method of the mid-wave infrared integrated polarization detector in this embodiment are as follows: Step (1) Spin coating: Prepare a mid-wave infrared detection chip 300 containing a pn junction region 302, and spin coat a first glue layer 303 on some sides of the pn junction region 302 of the mid-wave infrared detector chip facing away. Specifically, the material of the first glue layer 303 is ultraviolet photoresist.

[0035] Step (2) Patterning: Perform patterning on the first glue layer 303 spin coated in step (1), that is, expose the photoresist in the first glue layer 303, then wash off the unnecessary glue through the development process, and then through the fixing and drying processes, form the required photoresist pattern on the first glue layer 303. The photoresist pattern is a deep groove 301A arranged in a grid pattern. Specifically, the width of the deep groove 301A is 4 μm.

[0036] Step (3) Etching: After the patterning in step (2) is completed, send the obtained structure into an etching machine for etching to obtain an isolation groove 301A arranged in a grid pattern. The depth of the isolation groove is 5 μm, and the width of the isolation groove is 4 μm.

[0037] Step (4) Filling the isolation groove with ZnS: After the etching in step (3) is completed, put the obtained structure into a coating machine to deposit a 4-μm-thick zinc sulfide layer 301B, and fill zinc sulfide in the isolation groove 301A to obtain an isolation member 301.

[0038] Step (5) De-gumming: After the filling of the isolation groove 301A in step (4) is completed, the obtained overall structure is put into an acetone solution for cleaning to remove the residual first glue layer 303 on the surface of the mid-wave infrared detection chip 300, and a mid-wave infrared detector chip containing the zinc sulfide isolator 301 is obtained.

[0039] Step (6) Coating ZnS: After step (5) is completed, a zinc sulfide thin film is deposited on one side surface of the isolator 301 of the mid-wave infrared detector chip as the dielectric film layer 200. The thickness of the dielectric film layer 200 is 500 nm, which has an antireflection effect on the 3-5 μm infrared incident light 600.

[0040] Step (7) Coating Al: A metal thin film 100A made of aluminum is magnetron sputtered on the zinc sulfide thin film, i.e., the dielectric film layer 200. The thickness of aluminum is 100 nm. The thickness of the metal thin film 100A layer made of aluminum only needs to exceed the skin depth of the metal, that is, exceed dozens of nanometers.

[0041] Step (8) Spin-coating glue: A second glue layer 101 is spin-coated on the metal thin film 100A of the mid-wave infrared detector chip after coating. The material of the second glue layer 101 is nanoimprint glue.

[0042] Step (9) Patterning: The second glue layer 101 spin-coated in step (8) is patterned, that is, the nanoimprint glue in the second glue layer 101 is imprinted. The template is contacted with the second glue layer 101 coated, and the pattern is transferred to the nanoimprint glue by applying pressure. Then, the pattern is cured by irradiating with ultraviolet light. Finally, the pressure is released, and the template is separated from the second glue layer 101 forming the imprinted glue pattern, and multiple structures arranged in a periodic array are obtained.

[0043] Step (10) Etching: After patterning is completed, the obtained structure is sent into an etching machine for etching to obtain multiple polarization gratings 100 arranged in a periodic array. The polarization grating 100 includes a number of grating units. The grating unit period is 400 nm, the grating unit line width is 200 nm, and the grating unit length is 25 μm. The size of the polarization grating 100 is 25 μm × 25 μm, and the distance between adjacent polarization gratings 100 is 5 μm. The polarization grating 100 and the photosensitive pixels of the mid-wave infrared detection chip 300 are in one-to-one correspondence, and four adjacent polarization gratings 100 form a super pixel. The directions of the four polarization gratings 100 within the super pixel are different, which are 0°, 45°, 90°, and 135° respectively.

[0044] Step (11) De-gluing: After etching is completed, the obtained grating structure is placed in an acetone solution for cleaning to remove the residual second glue layer 101 on the polarization grating 100, so that the surfaces of each polarization grating 100 except the side in contact with the dielectric film layer 200 are exposed to the air, and the structure of the nanoscale polarization grating 100 is obtained.

[0045] Step (12) Flip-chip bonding: After de-gluing is completed, the side of the mid-wave infrared detection chip 300 facing away from the polarization grating 100 and the readout circuit 400 are connected by indium pillars 500 through a flip-chip bonding process to obtain a mid-wave infrared integrated polarization detector.

[0046] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present disclosure. However, the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A mid-wave infrared integrated polarization detector, characterized in that, The mid-wave infrared integrated polarization detector includes a plurality of polarization gratings arranged in a periodic array, a dielectric film layer, and a mid-wave infrared detection chip, which are arranged in sequence. The mid-wave infrared detection chip has a plurality of pn junction regions arranged in a periodic array, and the pn junction regions are arranged in one-to-one correspondence with the polarization gratings. The mid-wave infrared detection chip has a plurality of isolation grooves, and the isolation grooves are correspondingly arranged between two adjacent polarization gratings, and the isolation grooves are filled with isolation members.

2. The mid-wave infrared integrated polarization detector according to claim 1, wherein The isolation groove extends from the side of the mid-wave infrared detection chip close to the dielectric film layer to the side away from the dielectric film layer.

3. The mid-wave infrared integrated polarization detector according to claim 2, characterized in that The isolation member is in contact with the dielectric film layer.

4. The mid-wave infrared integrated polarization detector according to claim 2, wherein The depth of the isolation groove is 5 μm, and the width of the isolation groove is 4 μm.

5. The mid-wave infrared integrated polarization detector according to claim 1, wherein The material of the isolation member is zinc sulfide.

6. The mid-wave infrared integrated polarization detector according to claim 1, wherein Four adjacent polarization gratings form a super pixel, and the directions of the four polarization gratings of the super pixel are different.

7. The mid-wave infrared integrated polarization detector according to claim 1, wherein The polarization grating includes 62 grating units arranged in a periodic array. The period of the grating unit is 400 nm, the line width of the grating unit is 200 nm, the size of the polarization grating is 25 μm × 25 μm, and the distance between two adjacent polarization gratings is 30 μm.

8. The mid-wave infrared integrated polarization detector according to claim 1, wherein The mid-wave infrared detection chip also has a plurality of pn junction regions arranged in a periodic array. The pn junction regions extend from the side of the mid-wave infrared chip away from the dielectric film layer to the side close to the dielectric film layer, and each pn junction region is arranged corresponding to one polarization grating.

9. The mid-wave infrared integrated polarization detector according to claim 1, wherein The material of the dielectric film layer is zinc sulfide, the material of the polarization grating is aluminum, and the material of the mid-wave infrared detection chip is mercury cadmium telluride.

10. A method for fabricating a mid-wave infrared integrated polarization detector for fabricating the mid-wave infrared integrated polarization detector according to any one of claims 1 to 9, characterized in that, The preparation method includes: Preparing a mid-wave infrared detection chip containing a plurality of pn junction regions; Preparing a plurality of isolation grooves on the side of the mid-wave infrared detection chip away from the pn junction regions, and filling zinc sulfide in the isolation grooves to form isolation members; Preparing a dielectric film layer on the side of the mid-wave infrared detection chip away from the pn junction regions; Using nanoimprint technology to prepare a polarization grating on the side of the dielectric film layer away from the mid-wave infrared detection chip; Flip-chip welding the side of the pn junction region of the mid-wave infrared detection chip to the readout circuit to form a mid-wave infrared integrated detector.

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