Vertical plasmon polariton slit waveguide device structure capable of being coupled by optical fiber and preparation method of vertical plasmon polariton slit waveguide device structure

Abstract

The invention discloses a vertical plasmon waveguide device structure capable of being coupled by an optical fiber and a preparation method of the vertical plasmon waveguide device structure, and belongs to the technical field of integrated optoelectronics, and the structure is composed of a pair of metal gratings and a vertical metal-medium-metal plasmon waveguide. The structure comprises a silicon substrate layer, a lower metal layer, a dielectric layer and an upper metal layer which are arranged from bottom to top and is divided into a grating area and a waveguide area, the grating area comprises a dielectric grating area and a metal grating layer, and the waveguide structure comprises the lower metal layer, the dielectric layer and the upper metal layer. According to the design of the invention, the limitation of mass production caused by an overlay process of a mode converter between heterogeneous integrated waveguides is avoided, and the preparation robustness of the device is improved. The optical insertion loss caused by the roughness of the side wall of the waveguide is improved in a metal deposition-dielectric spin coating-metal deposition mode, and the dielectric layer can be replaced to realize multiple device functions.

Description

Technical Field

[0001] The invention relates to a vertical plasmon slit waveguide device structure capable of optical fiber coupling and a preparation method thereof, and belongs to the field of integrated optoelectronic devices. Background Art

[0002] With the rapid development of information processing technology, the growing demand for applications is driving the development of integrated optoelectronic devices towards lower power consumption, larger bandwidth and smaller size. Integrated plasmonic waveguide devices can confine light waves to a region much smaller than the free-space wavelength, achieving light field enhancement and controlling and manipulating optical information. At the same time, the strong light field localization characteristics of plasmonic structures have very obvious advantages over other integrated optical structures in enhancing the interaction between light and matter. Introducing plasmonic waveguide structures into the core components of integrated optoelectronic links, modulators and detectors, will help achieve high-speed, low-power optoelectronic information conversion functions. The light field enhancement brought about by the field localization effect of plasmonic waveguides and the ultra-high sensitivity to changes in the optical properties of the surrounding medium have particularly outstanding advantages in realizing optical nonlinear regulation, sensing detection and bio-optical imaging.

[0003] Plasmons are typically generated by the collective oscillation of free electrons at a metal-dielectric interface when light is incident. Due to this characteristic's influence on the morphology of the metal-dielectric interface and the inherent optical absorption properties of metals, optical losses are higher compared to other integrated waveguides (such as silicon-based integrated waveguides). Plasmonic slot waveguides are typically constructed from a metal-insulator-metal (MIM) structure. Light waves propagate along the metal-dielectric interface, coupling occurs between the two interfaces. Compared to other plasmonic waveguide structures, they offer low optical losses and long propagation distances, offering distinct advantages in integrated plasmonic waveguide devices. In MIM slot waveguide structures, the width of the slot determines the strength of the coupling. In the communications band, the slot width is typically 160nm or less, requiring control of the slot size to minimize losses in the light transmission waveguide. Horizontal plasmonic slot waveguides are difficult to fabricate due to their small feature size, and the lift-off process results in high metal sidewall roughness, making waveguide losses difficult to control. Furthermore, mode matching between light and plasmons is difficult. For example, in a 1550nm single-mode waveguide, the silicon waveguide optical mode field is 450nm × 220nm, while the plasmon slit waveguide mode field is 100nm × 100nm, with high momentum. The optical mode, on the other hand, is larger and has lower momentum, making mode conversion between light and plasmons more difficult. Furthermore, existing silicon-plasmon mode converters have poor robustness and narrow process tolerances, hindering practical applications. Summary of the Invention

[0004] In response to the above-mentioned problems, the purpose of the present invention is to provide a vertical plasmon slot waveguide device structure and preparation method that can be used for optical fiber coupling, so as to solve the problems existing in existing silicon-based plasmon waveguide devices, such as poor robustness, large transmission loss of the MIM structure of the plasmon waveguide structure, poor matching with the optical mode, resulting in large tolerance of the mode converter preparation when coupled with the optical fiber.

[0005] To achieve the above objectives, the present invention first provides a vertical plasmon slot waveguide device structure that can be coupled with an optical fiber. The structure includes a substrate and a metal layer and a waveguide structure sequentially deposited on the substrate. The waveguide structure includes a vertical plasmon slot waveguide unit and a metal grating unit connected at both ends of the vertical plasmon slot waveguide unit. The metal grating unit includes a dielectric grating layer and a metal grating layer sequentially deposited on the metal layer. The vertical plasmon slot waveguide unit includes a dielectric waveguide layer and a metal waveguide layer sequentially deposited on the metal layer. The metal grating layer, the dielectric grating layer, and the metal layer constitute a light-to-plasmon mode conversion region, i.e., a metal grating region. The metal layer, the dielectric waveguide layer, and the metal waveguide layer constitute a plasmon slot waveguide.

[0006] In the structure of the present invention, starting from the direction of light incidence, the light in the optical fiber is input from one end of the grating and transmitted along the dielectric layer, and is output from the metal grating at the other end to the output optical fiber. The period and duty cycle of the grating are related to the incident wavelength and the angle of the incident light, and the length of the grating area is related to the core aperture of the incident optical fiber.

[0007] The optical mode is coupled from the fiber mode to the plasmon mode, which is mainly achieved by converting the light-to-plasmon mode through a grating composed of metal-dielectric-metal. The grating acts as a Bragg reflector to guide the light to couple into the vertically stacked plasmon slit waveguide. The grating provides additional momentum to the incident light to match its momentum with the mode in the plasmon slit waveguide. The width and depth of the grating are related to the core diameter of the optical fiber. As the width of the waveguide or grating increases, the fiber coupling efficiency will decrease slightly and tend to stabilize. The present invention provides a dielectric grating layer consistent with the upper metal grating to increase the depth of the grating control to match the optical mode field size emitted by optical fibers of different diameters.

[0008] In one embodiment of the present invention, the substrate comprises a silicon substrate layer and a buried oxide layer deposited on the silicon substrate layer. The buried oxide layer is preferably silicon oxide, and the thickness of the buried oxide layer is 2 to 3 μm.

[0009] In one embodiment of the present invention, the metal layer can be made of at least one of gold (Au), silver (Ag), titanium (Ti), aluminum (Al), etc., and the thickness of the metal layer is 100 to 200 nm.

[0010] In one embodiment of the present invention, the dielectric grating layer and dielectric waveguide layer materials can be selected from any one of aluminum oxide, silicon oxide, organic polymer (SU8, PMMA, electro-optical polymer), lithium niobate, barium titanate and the like, preferably polymer SU8 that can be directly patterned.

[0011] In the present invention, the thickness d of the dielectric grating layer and the dielectric waveguide layer can meet the phase matching condition of the mode conversion process, and the thickness of the dielectric waveguide layer represents the width of the vertical plasmon slot waveguide.

[0012] In one embodiment of the present invention, the thickness d of the dielectric grating layer and the dielectric waveguide layer is preferably 100-180 nm.

[0013] In one embodiment of the present invention, the metal grating layer and the metal waveguide layer may be made of at least one of gold (Au), silver (Ag), titanium (Ti), aluminum (Al), etc., preferably Au.

[0014] In one embodiment of the present invention, the length L of the metal grating region is gc The grating period is 0.98 to 1.2 μm, the duty cycle is 0.35 to 0.65 (depending on the wavelength of the incident light), and the length L of the plasmon slit waveguide unit is 8 to 30 μm. wg 10~30μm, width W wg 2 to 5 μm (depending on the core diameter of the incident optical fiber).

[0015] In one embodiment of the present invention, when a common optical fiber with an incident light wavelength of 1550 nm (core diameter of 9.5 μm) is selected, the metal layer material is preferably Ti / Au, and the thickness of the metal layer is preferably 5 nm / 130 nm; the dielectric layer material is preferably SU8, and the thickness d is preferably 120 nm; the metal grating layer or metal waveguide layer is preferably Ti / Au, and the thickness of the metal grating layer or metal waveguide layer is preferably 5 nm / 130 nm; the plasmon slit waveguide width W is preferably 100 nm. wg 4 μm, length L wg is 23.3μm, and the grating width W gc 8μm, the grating period is 1.05nm, the duty cycle is 0.4, and the grating length L gc The thickness of the Ti / Au layer is 28 μm. Ti / Au refers to a stacked structure of Ti and Au layers, with the bottom layer being a Ti layer and the top layer being an Au layer.

[0016] The present invention also provides a method for preparing the vertical plasmon slot waveguide device structure, comprising the following steps:

[0017] (1) Depositing a metal layer on the top silicon oxide layer of a CMOS-compatible substrate;

[0018] (2) spin coating or depositing a dielectric layer on the metal layer obtained in step (1), and completing the preparation of the dielectric layer in the metal grating area through a patterning process;

[0019] (3) spin-coating photoresist on the device obtained in step (2), and completing the patterning of the upper metal structure by an overlay process;

[0020] (4) depositing a metal film on the device obtained in step (3), and obtaining a metal grating region and a waveguide after peeling off, thereby forming a vertically stacked metal-dielectric layer-metal structure, i.e., a vertical plasmon slit integrated waveguide.

[0021] In one embodiment of the present invention, in step (1), the metal layer is prepared by electron beam evaporation, thermal evaporation or magnetron sputtering.

[0022] In one embodiment of the present invention, in step (2), a dielectric layer such as silicon oxide, aluminum oxide, or ITO is prepared by atomic layer deposition, thermal evaporation, or magnetron sputtering; a polymer dielectric layer such as SU8 or electro-optical polymer is prepared by spin coating, drop coating, or coating, and the film thickness is controlled by controlling the solution concentration, the spin coater speed, or the like. The dielectric layer is patterned by electron beam patterning and deep ultraviolet lithography. The pattern transfer of the dielectric is accomplished by stripping, dry etching, and wet etching.

[0023] In one embodiment of the present invention, in step (3), PMMA495K photoresist is selected as the photoresist, and the overlay mark size accuracy is 500 nm. Specifically, the metal waveguide layer pattern or the metal grating layer pattern can be exposed on the dielectric layer using electron beam exposure or ultraviolet lithography. After development, a metal thin film is deposited, and the metal grating layer and waveguide structure are obtained by peeling off.

[0024] In one embodiment of the present invention, in steps (1) and (4), the material of the metal layer or the metal grating layer or the metal waveguide layer is titanium / gold (Ti / Au), which is prepared by electron beam evaporation, titanium serves as the adhesion layer, gold serves as the electrode layer, and acetone serves as the reagent used for stripping.

[0025] The present invention also discloses an application of the vertical plasmon slot waveguide device structure in the field of integrated circuits.

[0026] Beneficial effects:

[0027] (1) The present invention connects metal gratings at both ends of a vertical plasmon slit waveguide, and the metal grating has a metal-dielectric layer structure. The metal grating can act as a Bragg reflector. When light in an optical fiber is incident at a certain angle into a coupling grating region composed of an upper metal grating, a dielectric grating region, and a lower metal layer, it is coupled into the vertical plasmon slit waveguide composed of a lower metal layer, a dielectric layer, and an upper metal layer through diffraction. The grating provides missing momentum for the incident light, so that it matches the momentum of the vertical plasmon slit waveguide mode. This structure allows light to easily perform mode conversion between the grating and the plasmon waveguide, and mode conversion can be completed without the need for special optical fibers, thereby greatly reducing the cost of using special optical fibers.

[0028] (2) The present invention patterns the dielectric layer in the same manner as the upper metal layer to construct a coupled grating region consisting of an upper metal grating-a dielectric grating region-a lower metal layer, thereby increasing the modulation depth of the grating and reducing the scattering loss caused by the unevenness of the metal sidewall. The optical mode field size can reach 120nm×260nm, and fiber coupling can be achieved using ordinary optical fiber (core 9.5μm), which greatly improves the practicality of the waveguide device.

[0029] (3) In the waveguide device structure of the present invention, the thickness of each layer can be precisely controlled during the deposition process. Compared to plasmonic slot waveguides fabricated using etching or lift-off processes, the waveguide of the present invention has a smooth metal surface. This significantly reduces the transmission loss of the plasmonic waveguide device when the slit gap is small, improving device robustness and achieving the device function of low loss and high mode conversion efficiency. By vertically stacking metal waveguide devices without etching and chemical mechanical polishing processes, the fabrication tolerance of the mode conversion region of the plasmonic slot waveguide is released, making it suitable for conventional optical packaging solutions and can be used for large-scale production of high-performance plasmonic hybrid integrated optoelectronic devices.

[0030] (4) The dielectric grating layer and the dielectric waveguide layer are made of SU8 polymer, and the patterning of the coupling grating area can be directly achieved by electron beam lithography. The thickness of the dielectric layer can be effectively controlled by the rotation speed and ratio. The waveguide device of the present invention has a small optical insertion loss. The period, length, depth and duty cycle of the coupling grating area composed of the upper metal grating-dielectric grating area-lower metal can be set according to different incident optical fiber core diameters, which greatly increases the flexibility and practicality of the device design.

[0031] (5) The present invention avoids the mass production limitations caused by the overlay process of mode converters between heterogeneous integrated waveguides by designing the device into a vertical structure of metal-dielectric-metal waveguide and metal grating connection, thereby increasing the robustness of device preparation. The metal-dielectric surface characteristics are precisely controlled by the method of metal deposition-dielectric spin coating-metal deposition, the optical insertion loss caused by the roughness of the waveguide sidewall is improved, and the optical insertion loss of the plasmon device and the optical local characteristics are balanced to facilitate the realization of multiple functions of optoelectronic devices. The MIM metal grating structure is used to achieve optical coupling with conventional optical fiber (core diameter 8-10μm), which improves the demand for specialized optical fiber and the demand for heterogeneous mode converters. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a vertical plasmon slot waveguide device that can be coupled with an optical fiber according to the present invention;

[0033] Figure 2 Schematic diagram of the optical mode field of the device (including the fiber coupling part) in Example 1;

[0034] Figure 3 The whole and local scanning electron microscope images and microscope images of Example 1 are shown;

[0035] Figure 4 Graph showing the transmission loss of the vertically stacked plasmonic slot waveguide device in Example 1;

[0036] Figure 5 Schematic diagram of the preparation process of the vertical plasmon slot waveguide device in Example 1;

[0037] Figure 6 This is a coupling test diagram of the vertical plasmon slot waveguide device in Example 1;

[0038] Figure 7 Schematic diagram of the vertical plasmon slot waveguide device structure in Comparative Example 1. DETAILED DESCRIPTION

[0039] In order to make the objects, features and advantages of the present invention more clearly understood, a detailed description is given below using specific embodiments. In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in the various embodiments of the present invention can be combined accordingly without conflicting with each other.

[0040] The procedures for the following examples, in which specific conditions are not specified, generally follow conventional conditions or those recommended by the manufacturer. Any material not described in detail in this specification belongs to the prior art known to those skilled in the art. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0041] Example 1

[0042] A vertically stacked plasmonic slot waveguide structure that can be coupled with optical fibers, such as Figure 1 As shown, it includes a substrate compatible with CMOS technology (composed of a silicon wafer and 3μm silicon oxide deposited on the silicon wafer), a lower metal (titanium / gold) and a waveguide structure sequentially deposited on the substrate, wherein the waveguide structure includes a vertical plasmon slit waveguide unit and a metal grating unit connected at both ends of the vertical plasmon slit waveguide unit. The metal grating unit includes a dielectric grating layer (SU8, with a refractive index of 1.56) and a metal grating layer (titanium / gold) sequentially deposited on the surface of the lower metal. The vertical plasmon slit waveguide unit includes a dielectric waveguide layer (SU8) and a metal waveguide layer (titanium / gold) sequentially deposited on the surface of the lower metal. In the metal grating unit, the width W of the metal grating region is gc 8μm, length L gc The width of the vertical plasmon slit waveguide unit is W wg 4 μm, length L wg The thickness of the lower titanium / gold layer is 5 / 130nm, the thickness d of the dielectric grating layer and the dielectric waveguide layer is 120nm, and the thickness of the titanium / gold layer of the metal grating layer and the metal waveguide layer is 5 / 130nm.

[0043] The optical fiber used for fiber coupling is a 1550nm single-mode optical fiber with a core diameter of 9.5μm.

[0044] A method for preparing a vertically stacked plasmonic slot waveguide structure that can be coupled with an optical fiber, such as Figure 5 As shown, the following steps are included:

[0045] (1) Deposit the lower metal film by electron beam evaporation on the top silicon oxide layer of the clean CMOS substrate, with titanium / gold thickness of 5 / 130nm;

[0046] (2) Spin-coat diluted SU82000.5 photoresist on the underlying metal layer and pattern the dielectric grating area using electron beam exposure technology or ultraviolet lithography;

[0047] (3) Spin-coating PMMA495K photoresist on the device obtained in step (2), and patterning the upper metal grating using electron beam exposure technology or ultraviolet lithography technology, with the overlay mark size accuracy within 500nm;

[0048] (4) A metal film is prepared on the device obtained in step (3) by electron beam evaporation, with a titanium / gold thickness of 5 / 130 nm, and a vertically stacked plasmon slit waveguide structure is formed after peeling.

[0049] Figure 2 is a cross-sectional view of the optical mode field of the device at different positions of the vertical plasmon slit integrated waveguide structure in this embodiment, Figure 2 The dotted lines in the middle represent the locations of the various structures.

[0050] The finite element analysis method is used to simulate the proposed embodiment 1. Specifically, the light in the optical fiber is incident at a certain angle into the coupling grating area composed of the upper metal grating-dielectric grating area-lower metal, and is coupled to the vertical plasmon slit waveguide composed of the lower metal-dielectric layer-upper metal through diffraction. The metal grating can be regarded as a Bragg reflector. The light oscillates stably in the metal grating and meets the resonance conditions of the Fabry-Perot cavity (FP). In this process, the grating provides missing momentum for the incident light, so that it matches the momentum of the vertical plasmon slit waveguide mode. Through simulation calculation of the coupling efficiency, it was found that when the coupling efficiency is the highest, the thickness of the upper metal is half the wavelength of the light propagating in the vertical plasmon slit. This shows that the coupling efficiency is significantly dependent on the thickness of the upper metal at a specific wavelength, which is strongly related to the FP resonance condition. The coupling picture is shown in FIG. Figure 6 shown.

[0051] Figure 3 The field emission scanning electron microscope image of the grating-coupled vertical plasmon hybrid integrated waveguide structure of Example 1 is shown. The width W of the vertically stacked plasmon slit waveguide is wg 4 μm, length L wg It is 23.3μm.

[0052] Under this condition, if Figure 4 The transmission loss of the vertically stacked plasmonic slot waveguide region, calculated from the difference in transmission loss, is 0.46 dB / μm. The success rate of fabricating this type of device is greatly increased compared to that of traditional two-dimensional planar silicon-based plasmonic slot waveguides. The light-to-plasmon mode conversion is completed by a metal grating, and the insertion loss of 90% of the devices can be maintained at a similar level. The single-ended insertion loss of the grating is reduced to 5.6 dB, and the optical bandwidth reaches 35 nm. This provides a mass production solution for the widespread application of plasmonic waveguide devices in miniaturized, large-bandwidth, high-efficiency optoelectronic devices and nonlinear optical regulation.

[0053] Example 2

[0054] The only difference between Example 2 and Example 1 is that the dielectric layer is made of SiO2 deposited by thermal evaporation, and the grating region can be prepared by photolithography or mask technology.

[0055] This example also demonstrates the impact of SiO2 dielectric layers of varying thickness (100nm, 120nm, and 150nm) on the final device loss. This dielectric layer verifies that the structure exhibits good process compatibility with dielectric layers prepared using different methods. Thinner dielectric layers increase coupling difficulty, but the light energy is more concentrated in the slit. As the dielectric layer thickness d increases, the light field energy gradually shifts toward the center of the dielectric layer and then concentrates in the dielectric layer, reducing the metal absorption loss of the mode conversion loss device.

[0056] The corresponding device is prepared according to Example 2, and the length of the vertical plasmon slot waveguide is L wg When the d is 20μm and the waveguide slit width (i.e., the dielectric layer thickness) is 100nm, the overall optical insertion loss of the device at the output port is approximately -21.75dB, the single-ended grating insertion loss is 6.75dB, and the transmission loss in the vertical plasmon slot waveguide region is 0.48dB / μm. For a device with a d of 150nm, the device loss at the output port is approximately -26.43dB, the single-ended grating insertion loss is 8.82dB, and the transmission loss in the vertical plasmon slot waveguide region is 0.44dB / μm. The insertion loss is caused by scattering losses due to sidewall unevenness generated during the peeling of the thermally evaporated silicon oxide layer.

[0057] In Example 2, the light-to-plasmon mode conversion loss varies with the fiber core diameter and the width of the grating region. For a stable core and waveguide width, the transmission loss decreases as the thickness d of the dielectric layer increases. This requires a trade-off between mode conversion loss and transmission loss based on the device's application scenario. To increase the interaction length between the active material and the light field to 20 μm and to concentrate the light field more within the plasmon waveguide region, a SiO2 thickness of 100 nm is most preferably used for device fabrication to reduce the device's total transmission loss.

[0058] Comparative Example 1

[0059] The difference between the comparative example and Example 1 is that it includes a substrate compatible with CMOS technology (composed of a silicon wafer and 2-3 μm silicon oxide deposited on the silicon wafer), a lower metal (gold) deposited on the substrate in sequence, an intermediate dielectric layer (SU8) and a waveguide structure, wherein the waveguide structure includes a vertical plasmon slit waveguide unit and a metal grating unit connected to both ends of the vertical plasmon slit waveguide unit. The metal grating unit is a metal grating layer (gold) deposited on the surface of the intermediate dielectric, and the vertical plasmon slit waveguide unit includes a dielectric waveguide layer (SU8) and a metal waveguide layer (gold) deposited in sequence on the surface of the lower metal layer, as shown in FIG. Figure 7 shown.

[0060] Experiments have found that this device structure is only applicable to special 1550nm optical fibers, and the core diameter of the optical fiber must be ≤2μm. The core diameter is designed to match the optical mode field size that can be converted by the full plasmon metal grating, further reducing the mode mismatch between the optical mode field size of the optical fiber core output and the plasmon optical mode field size, and reducing the optical loss generated during the light-plasmon mode conversion process. The cost of this special optical fiber is extremely high, which is not conducive to mass production; and its maximum applicable optical mode field size is 100nm×140nm, which greatly limits practical applications. At the same time, the grating modulation depth of the plasmon device needs to rely on the thickness of the metal, but the metal thickness is limited by thin film stripping technology, and it is difficult to achieve high-quality metal devices greater than 300nm. If ordinary optical fiber is used, its transmission loss will be dozens of times that of Example 1, which is not conducive to practical application.

[0061] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A vertical plasmon slot waveguide device structure that can be coupled with an optical fiber, characterized in that: The structure includes a substrate and a metal layer and a waveguide structure sequentially deposited on the substrate. The waveguide structure includes a vertical plasmon slot waveguide unit and a metal grating unit connected at both ends of the vertical plasmon slot waveguide unit. The metal grating unit includes a dielectric grating layer and a metal grating layer sequentially deposited on the metal layer. The vertical plasmon slot waveguide unit includes a dielectric waveguide layer and a metal waveguide layer sequentially deposited on the metal layer. The metal grating layer, the dielectric grating layer and the metal layer constitute a metal grating region, and the metal layer, the dielectric waveguide layer and the metal waveguide layer constitute a plasmon slot waveguide.

2. The device structure according to claim 1, characterized in that The substrate comprises a silicon substrate layer and a buried oxide layer deposited on the silicon substrate layer, wherein the thickness of the buried oxide layer is 2-3 μm.

3. The device structure according to claim 1, wherein: The metal layer or metal grating layer or metal waveguide layer includes one or a combination of two or more metals selected from the group consisting of gold, silver, titanium and aluminum, and the thickness of the metal layer is 100 to 200 nm.

4. The device structure according to claim 1, wherein: The dielectric grating layer and dielectric waveguide layer are made of any one or a combination of aluminum oxide, silicon oxide, organic polymer, lithium niobate, and barium titanate. The organic polymer includes any one of SU8, PMMA, and electro-optic polymer.

5. The device structure according to claim 1, wherein: The thickness of the dielectric grating layer or dielectric waveguide layer is 100-180 nm.

6. The device structure according to claim 1, wherein: The length of the metal grating region is 8 to 30 μm, the width is 4 to 10 μm, the grating period is 0.98 to 1.2 μm, the duty cycle is 0.35 to 0.65, and the length of the plasmon slit waveguide unit is 10 to 30 μm, and the width is 2 to 5 μm.

7. The method for preparing a vertical plasmon slot waveguide device structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Depositing a metal layer on the top silicon oxide layer of a CMOS-compatible substrate; (2) spin coating or depositing a dielectric layer on the metal layer obtained in step (1), and completing the preparation of the dielectric layer in the metal grating area through a patterning process; (3) spin-coating photoresist on the device obtained in step (2), and completing the patterning of the upper metal structure by an overlay process; (4) depositing a metal film on the device obtained in step (3), and obtaining a metal grating region and a waveguide after peeling off, thereby forming a vertically stacked metal-dielectric layer-metal structure, i.e., a vertical plasmon slit integrated waveguide.

8. The preparation method according to claim 7, characterized in that In step (2), the preparation method of the dielectric layer includes atomic layer deposition, thermal evaporation, magnetron sputtering, spin coating, drop coating, and coating; the patterning process includes electron beam patterning or ultraviolet lithography.

9. The preparation method according to claim 7, characterized in that In steps (1) and (4), the material of the metal layer or metal grating layer or metal waveguide layer is titanium / gold (Ti / Au), which is prepared by electron beam evaporation, titanium serves as the adhesion layer, gold serves as the electrode layer, and acetone serves as the reagent used for stripping.

10. Application of the vertical plasmon slot waveguide device structure according to any one of claims 1 to 6 in the field of integrated circuits.

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