Superlens and manufacturing method thereof
By using a method of stacking low-hydrogen-dilution-ratio hydrogenated amorphous silicon layers with high-hydrogen-dilution-ratio hydrogenated amorphous silicon layers in the fabrication of superlenses, the problem of bubble defects was solved, optical performance with low extinction coefficient was achieved, production efficiency was improved and costs were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2026-03-10
AI Technical Summary
Existing superlenses are prone to bubble defects during manufacturing and have a high extinction coefficient, making it difficult to meet optical performance requirements.
Using a hydrogenated amorphous silicon layer with a low hydrogen dilution ratio as a base, a hydrogenated amorphous silicon layer with a high hydrogen dilution ratio is stacked and grown. By controlling the flow ratio of hydrogen and dilution gas, bubble defects are reduced during the deposition process, and hydrogen diffusion is carried out during the subsequent thermal process to reduce dangling bonds and defects, thereby improving the interface quality.
This effectively avoids bubble defects, reduces the extinction coefficient, meets the optical performance requirements of superlenses, improves production efficiency, and reduces costs.
Smart Images
Figure CN121629353A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to optical lenses, and more particularly to a superlens, and also to a method for manufacturing a superlens. Background Technology
[0002] A superlens is a planar optical lens manufactured in large quantities using semiconductor chip technology. It possesses surface micro / nano structures that modulate the phase of incident light to converge and form an image. See also... Figure 1 It includes a substrate 110 and multiple columnar microstructures 120 on the substrate 110. The superlens has the following characteristics: thin - compared with the thickness of traditional lens groups in the millimeter to decimeter range, the thickness of the superlens is in the hundreds of nanometers to micrometer range; light - compared with traditional lenses, the weight of the superlens is negligible; simple - compared with the complex lens group system of traditional lenses, the superlens can concentrate all functions into one or two metasurfaces.
[0003] Exemplary examples of hydrogenated amorphous silicon columnar microstructures grown using plasma-enhanced chemical vapor deposition (PECVD) sometimes exhibit bubble defects, such as... Figure 2a and Figure 2b As shown. Summary of the Invention
[0004] Therefore, it is necessary to provide a superlens and its manufacturing method that can avoid bubble defects while ensuring a sufficiently small extinction coefficient.
[0005] A method for manufacturing a superlens includes: depositing a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on a substrate; introducing hydrogen gas and a dilution gas during the deposition process, wherein the flow rate ratio of hydrogen gas to dilution gas introduced during the deposition of the second hydrogenated amorphous silicon layer is greater than the flow rate ratio of hydrogen gas to dilution gas introduced during the deposition of the first hydrogenated amorphous silicon layer; patterning the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form a plurality of columnar microstructures; each columnar microstructure includes the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer on the first hydrogenated amorphous silicon layer.
[0006] The aforementioned method for manufacturing the superlens involves stacking a hydrogenated amorphous silicon layer (i.e., the second hydrogenated amorphous silicon layer) deposited at a high hydrogen dilution ratio onto a hydrogenated amorphous silicon layer (i.e., the first hydrogenated amorphous silicon layer) with a low hydrogen dilution ratio. The low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer exhibits better adhesion to the substrate, and its hydrogen outgassing is relatively low (compared to the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer), thus reducing the likelihood of bubble defects and improving the interface quality at the contact point between the columnar microstructure and the substrate. During subsequent thermal processes, hydrogen from the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer diffuses into the low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer, effectively reducing dangling bonds and defects in the low-hydrogen-dilution-ratio layer, thereby lowering the extinction coefficient and meeting the extinction coefficient requirements of the superlens.
[0007] In one embodiment, during the formation of the sacrificial layer and the hard mask layer, hydrogen in the second hydrogenated amorphous silicon layer diffuses into the first hydrogenated amorphous silicon layer.
[0008] In one embodiment, the diluent gas is SiH4.
[0009] In one embodiment, the flow rate ratio of hydrogen to SiH4 introduced during the deposition of the second hydrogenated amorphous silicon layer is 5 to 20, and the flow rate ratio of hydrogen to SiH4 introduced during the deposition of the first hydrogenated amorphous silicon layer is ≤4.
[0010] In one embodiment, the SiH4 flow rate during the deposition process is from 5 sccm to 165 sccm.
[0011] In one embodiment, the step of patterning the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form a plurality of columnar microstructures includes: forming a sacrificial layer on the second hydrogenated amorphous silicon layer; patterning the sacrificial layer, removing the sacrificial layer directly above the location where each columnar microstructure is to be formed, forming a plurality of pits; forming a hard mask layer covering the sacrificial layer and the second hydrogenated amorphous silicon layer; removing the hard mask layer above the sacrificial layer, while retaining the hard mask layer in the pits; removing the remaining sacrificial layer; and using the remaining hard mask layer as an etching mask to etch the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form each columnar microstructure.
[0012] In one embodiment, the sacrificial layer is a silicon nitride layer and the hard mask layer is a silicon dioxide layer.
[0013] In one embodiment, the formation of the sacrificial layer and the formation of the hard mask layer are formed by deposition at a temperature of 400 to 540 degrees Celsius.
[0014] In one embodiment, the step of forming a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the substrate by deposition is carried out at a deposition temperature of 200 to 350 degrees Celsius.
[0015] In one embodiment, the step of forming a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the substrate by deposition is performed using a plasma-enhanced chemical vapor deposition process.
[0016] In one embodiment, the step of forming a sacrificial layer on the second hydrogenated amorphous silicon layer has a sacrificial layer thickness of 2000 Å to 4000 Å.
[0017] In one embodiment, the step of forming a hard mask layer covering the sacrificial layer and the second hydrogenated amorphous silicon layer involves forming a hard mask layer with a thickness of 5000 Å to 8000 Å.
[0018] In one embodiment, after the formation of the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer, no thermal annealing is performed until the columnar microstructures are formed.
[0019] In one embodiment, the n value of each of the columnar microstructures is 3 to 4.
[0020] In one embodiment, the extinction coefficient K of each of the columnar microstructures is ≤0.001 at a wavelength of 940 nm.
[0021] In one embodiment, the substrate is a quartz sheet.
[0022] In one embodiment, the critical dimensions of each of the columnar microstructures are 100 nanometers to 300 nanometers.
[0023] In one embodiment, the thickness of the second hydrogenated amorphous silicon layer is greater than the thickness of the first hydrogenated amorphous silicon layer.
[0024] A superlens includes: a substrate; and a plurality of columnar microstructures located on a first main surface of the substrate, each columnar microstructure including a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the first hydrogenated amorphous silicon layer, wherein the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer are formed by deposition and the gas introduced during the deposition process includes hydrogen and a dilution gas, wherein the flow rate ratio of hydrogen to dilution gas introduced during the deposition process of the second hydrogenated amorphous silicon layer is greater than the flow rate ratio of hydrogen to dilution gas introduced during the deposition process of the first hydrogenated amorphous silicon layer.
[0025] The aforementioned superlens features a hydrogenated amorphous silicon layer deposited at a high hydrogen dilution ratio (i.e., the second hydrogenated amorphous silicon layer) placed on top of a hydrogenated amorphous silicon layer with a low hydrogen dilution ratio (i.e., the first hydrogenated amorphous silicon layer). The low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer exhibits better adhesion to the substrate, while its hydrogen outgassing is relatively low (compared to the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer), thus reducing the likelihood of bubble defects and improving the interface quality at the contact point between the columnar microstructure and the substrate. Furthermore, hydrogen from the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer diffuses into the low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer during manufacturing via thermal processes, effectively reducing dangling bonds and defects in the low-hydrogen-dilution-ratio layer, thereby lowering the extinction coefficient and meeting the extinction coefficient requirements of the superlens.
[0026] In one embodiment, the n value of each of the columnar microstructures is 3 to 4.
[0027] In one embodiment, the extinction coefficient K of each of the columnar microstructures is ≤0.001 at a wavelength of 940 nm.
[0028] In one embodiment, the substrate is a quartz sheet.
[0029] In one embodiment, the critical dimensions of each of the columnar microstructures are 100 nanometers to 300 nanometers.
[0030] In one embodiment, the thickness of the second hydrogenated amorphous silicon layer is greater than the thickness of the first hydrogenated amorphous silicon layer.
[0031] In one embodiment, the diluent gas is SiH4.
[0032] In one embodiment, the flow rate ratio of hydrogen to SiH4 introduced during the deposition of the second hydrogenated amorphous silicon layer is 5 to 20, and the flow rate ratio of hydrogen to SiH4 introduced during the deposition of the first hydrogenated amorphous silicon layer is ≤4. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram of an exemplary superlens.
[0035] Figure 2a and Figure 2b This is a microscope image of a superlens exhibiting a bubble defect.
[0036] Figure 3 This is a flowchart of a method for manufacturing a superlens in one embodiment of this application.
[0037] Figure 4 This is a schematic diagram of the structure of a superlens in one embodiment of this application after step S110 of the manufacturing process is completed.
[0038] Figure 5 This is a schematic diagram of the structure of a superlens in one embodiment of this application.
[0039] Figure 6 This is a flowchart of a sub-step of step S120 in one embodiment of this application.
[0040] Figures 7a to 7c This is a schematic diagram of the superlens during the manufacturing process in one embodiment of this application.
[0041] Figure 8 This is a perspective view of a superlens in one embodiment of this application. Detailed Implementation
[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0044] It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only. When an element or layer is described as being "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be an intervening element or layer. Conversely, when an element is described as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, A, B, C, etc., may be used to describe various elements, components, areas, layers, and / or parts, these elements, components, areas, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.
[0045] When the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated feature, integral, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. The singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise.
[0046] Embodiments of the invention are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures) of the invention, thus allowing for variations in the illustrated shape due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of the invention.
[0047] An exemplary superlens requires an n-value of 3 to 4 for the hydrogenated amorphous silicon columnar microstructure, and an extinction coefficient K of ≤0.001 at a wavelength of 940 nm. For the hydrogenated amorphous silicon columnar microstructure grown by plasma-enhanced chemical vapor deposition (PECVD) in the superlens, the inventors believe that increasing the hydrogen dilution ratio during deposition helps reduce defects in the film and lower the extinction coefficient. However, subsequent thermal processes increase the crystallinity of the amorphous silicon, reducing the passivation effect. Simultaneously, annealing improves the film quality but alters the hydrogen bonding mode, increasing the extinction coefficient while generating bubble defects. The inventors believe that these bubble defects are due to hydrogen outgassing and poor adhesion between the PECVD-grown hydrogenated amorphous silicon columnar microstructure and the substrate (quartz sheet).
[0048] This application proposes a method for manufacturing a superlens, in which an amorphous silicon thin film deposited with a high hydrogen dilution ratio is stacked on an amorphous silicon thin film with a low hydrogen dilution ratio. During subsequent thermal processes, hydrogen in the amorphous silicon thin film with a high hydrogen dilution ratio diffuses into the amorphous silicon thin film with a low hydrogen dilution ratio, effectively reducing dangling bonds and defects in the amorphous silicon to reduce the extinction coefficient. At the same time, it improves the interface quality between the amorphous silicon and the quartz sheet and solves the problem of bubble defects. Figure 3 This is a flowchart of a method for manufacturing a superlens according to an embodiment of this application, including the following steps:
[0049] S110, a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer are formed on the substrate by deposition.
[0050] Reference Figure 4 A first hydrogenated amorphous silicon layer 222 and a second hydrogenated amorphous silicon layer 224 are deposited on a substrate 210, with the lower surface of the second hydrogenated amorphous silicon layer 224 in direct contact with the upper surface of the first hydrogenated amorphous silicon layer 222. Hydrogen and dilution gas are introduced during the deposition process, and the flow rate ratio of hydrogen to dilution gas introduced during the deposition of the second hydrogenated amorphous silicon layer 224 is greater than the flow rate ratio introduced during the deposition of the first hydrogenated amorphous silicon layer 222. The first hydrogenated amorphous silicon layer 222 and the second hydrogenated amorphous silicon layer 224 can be formed sequentially within the same equipment cavity.
[0051] In one embodiment of this application, step S110 involves deposition using a plasma-enhanced chemical vapor deposition process.
[0052] In one embodiment of this application, the dilution gas is SiH4.
[0053] In one embodiment of this application, the substrate 210 is a quartz sheet.
[0054] S120, patterning the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form multiple columnar microstructures.
[0055] Each columnar microstructure 220 includes a first hydrogenated amorphous silicon layer 222 and a second hydrogenated amorphous silicon layer 224 on the first hydrogenated amorphous silicon layer 222, as shown in the figure. Figure 5 .
[0056] The aforementioned method for manufacturing the superlens involves stacking a hydrogenated amorphous silicon layer (i.e., the second hydrogenated amorphous silicon layer 224) deposited at a high hydrogen dilution ratio onto a hydrogenated amorphous silicon layer (i.e., the first hydrogenated amorphous silicon layer 222) with a low hydrogen dilution ratio. The low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer exhibits better adhesion to the substrate 210, while its hydrogen outgassing is relatively low (compared to the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer). Therefore, it is less prone to bubble defects, improving the interface quality at the contact between the columnar microstructure 220 and the substrate 210. During subsequent thermal processes, hydrogen from the high-hydrogen-dilution-ratio hydrogenated amorphous silicon layer diffuses into the low-hydrogen-dilution-ratio hydrogenated amorphous silicon layer, effectively reducing dangling bonds and defects in the low-hydrogen-dilution-ratio layer, thereby lowering the extinction coefficient and meeting the extinction coefficient requirements of the superlens.
[0057] For example, a layer of silicon dioxide can be formed on the substrate 210 before depositing the hydrogenated amorphous silicon layer to increase the adhesion of the columnar microstructure to the substrate. However, this adds an extra process step, reducing production efficiency and increasing costs. This application adopts a scheme in which a second hydrogenated amorphous silicon layer 224 is stacked on the first hydrogenated amorphous silicon layer 222. Compared with the scheme of forming silicon dioxide on the substrate 210, since the first hydrogenated amorphous silicon layer 222 and the second hydrogenated amorphous silicon layer 224 can be formed sequentially in the same equipment cavity, the production efficiency is higher.
[0058] Since the first hydrogenated amorphous silicon layer 222 is mainly set to improve the interface quality at the contact between the columnar microstructure 220 and the substrate 210, and the main body of the columnar microstructure 220 is the second hydrogenated amorphous silicon layer 224, the second hydrogenated amorphous silicon layer 224 is set to be thicker than the thickness of the first hydrogenated amorphous silicon layer 222.
[0059] In one embodiment of this application, the flow ratio (H2:SiH4) of hydrogen gas to SiH4 introduced during step S110 to deposit the second hydrogenated amorphous silicon layer 224 is 5 to 20, and the flow ratio of hydrogen gas to SiH4 introduced during the deposition of the first hydrogenated amorphous silicon layer 222 is ≤4.
[0060] In one embodiment of this application, the SiH4 flow rate during step S110 deposition is 5 sccm to 165 sccm.
[0061] For example, polycrystalline silicon or amorphous silicon can be deposited using a furnace tube to form columnar microstructures. These columnar microstructures have a low hydrogen content, which can solve the bubble defect problem. However, the temperature for furnace tube deposition of polycrystalline / amorphous silicon typically reaches above 600 degrees Celsius, causing some damage to the quartz substrate and affecting subsequent processes. In one embodiment of this application, the deposition temperature in step S110 is 200 to 350 degrees Celsius. For embodiments where the substrate 210 is a quartz wafer, excessively high temperatures can damage the quartz wafer, thus affecting subsequent processes. Therefore, step S110 uses a lower-temperature deposition process, which has minimal impact on the quartz substrate and is more compatible with subsequent processes.
[0062] Figure 6 This is a flowchart of a sub-step of step S120 in one embodiment of this application. In this embodiment, step S120 specifically includes:
[0063] S121, a sacrificial layer is formed on the second hydrogenated amorphous silicon layer.
[0064] A sacrificial layer 230 is deposited on the second hydrogenated amorphous silicon layer. The sacrificial layer 230 is used to control the patterning of the subsequently formed hard mask layer 240. In one embodiment of this application, the sacrificial layer 230 is made of silicon nitride, such as silicon nitride.
[0065] S122, Patterned sacrificial layer, removes the sacrificial layer directly above the position where each columnar microstructure is to be formed.
[0066] In one embodiment of this application, photoresist is coated on the sacrificial layer 230, and then the photoresist is exposed using a corresponding photomask. After development, the remaining photoresist is used as an etching mask to etch the sacrificial layer 230, removing the areas of the sacrificial layer 230 without photoresist. A pit 231 is formed at the location where the sacrificial layer 230 is removed. (Refer to...) Figure 7a .
[0067] S123, forming a hard mask layer covering the sacrificial layer and the second hydrogenated amorphous silicon layer.
[0068] A hard mask layer is deposited on the sacrificial layer 230 and the second hydrogenated amorphous silicon layer 224, as referenced. Figure 7b In one embodiment of this application, the hard mask layer is made of silicon oxide, such as silicon dioxide.
[0069] S124, Remove the hard mask layer above the sacrificial layer.
[0070] In one embodiment of this application, the hard mask layer 240 above the sacrificial layer 230 can be removed by polishing (chemical mechanical planarization, CMP) or by etch back. The hard mask layer 240 in the pit 231 is retained.
[0071] S125, remove the remaining sacrificial layer.
[0072] An etchant with a high etch selectivity for both the material of the sacrificial layer 230 and the material of the hard mask layer 240 is selected to etch away the remaining sacrificial layer 230. In one embodiment of this application, the etching in step S125 is performed using wet etching.
[0073] S126 uses the remaining hard mask layer as an etching mask to etch and form columnar microstructures.
[0074] The first hydrogenated amorphous silicon layer 222 and the second hydrogenated amorphous silicon layer 224 are etched. After etching, the remaining hard mask layer 240 can be removed to obtain the desired result. Figure 5 The structure shown. In one embodiment of this application, step S126 employs dry etching.
[0075] As mentioned earlier, the high-temperature thermal process can damage the substrate quartz wafer. In one embodiment of this application, the deposition temperature for both steps S121 and S123 is 400 to 540 degrees Celsius. Damage to the substrate quartz wafer is minimized by controlling the deposition temperature. Furthermore, the thermal process of deposition in steps S121 and S123 is necessary to allow hydrogen to diffuse from the second hydrogenated amorphous silicon layer 224 to the first hydrogenated amorphous silicon layer 222; therefore, a suitable temperature is required to ensure that the hydrogen diffusion meets expectations. By reasonably controlling the deposition temperature of steps S121 and S123, hydrogen diffusion from the second hydrogenated amorphous silicon layer 224 to the first hydrogenated amorphous silicon layer 222 can be completed without additional thermal annealing. Therefore, in one embodiment of this application, thermal annealing is not performed after step S110 until step S126 is completed.
[0076] In step S126, the thickness of the hard mask layer 240 used as the etching mask needs to consider the material ratio of the hard mask layer 240 to the etching selectivity of the hydrogenated amorphous silicon layer, to avoid the hard mask layer 240 being completely consumed during the etching process. Figure 7c The thickness of the medium-hard mask layer 240 and Figure 7b The thickness d1 of the sacrificial layer 230 is the same. Taking both factors into consideration, in one embodiment of this application, the thickness d1 of the sacrificial layer 230 formed in step S121 is 2000 Å to 4000 Å; in one embodiment of this application, the thickness d2 of the hard mask layer 240 formed in step S123 (see...) Figure 7bThe range is 5000Å to 8000Å.
[0077] In one embodiment of this application, the n-value (refractive index) of the columnar microstructure 220 is 3 to 4.
[0078] In one embodiment of this application, the extinction coefficient K of each columnar microstructure 220 is ≤0.001 at a wavelength of 940nm.
[0079] In one embodiment of this application, the critical dimension (CD) of each columnar microstructure is 100 nanometers to 300 nanometers.
[0080] Based on all the above embodiments, this application first grows a thin a-Si:H film (i.e., the first hydrogenated amorphous silicon layer 222) with a low hydrogen dilution ratio. This amorphous silicon layer has good adhesion to the quartz sheet, but due to the large number of dangling bonds and defects, the extinction coefficient K is large. Then, a thicker a-Si:H film (i.e., the second hydrogenated amorphous silicon layer 224) is grown with a high hydrogen dilution ratio. Intrinsic amorphous silicon contains a large number of structural defects such as dangling bonds. Therefore, hydrogen gas is introduced during the deposition of intrinsic amorphous silicon film using PECVD. By saturating the dangling bonds in the amorphous silicon with hydrogen, the film becomes a hydrogenated intrinsic amorphous silicon film, and the defect density is significantly reduced. As the hydrogen dilution ratio increases, the defect state density of the a-Si:H film decreases, and the film becomes denser. Hydrogen in the hydrogenated amorphous silicon film mainly exists in the form of Si-H, Si-H2, and molecular hydrogen bonds. However, only Si-H bonds can passivate the dangling bonds in the amorphous silicon and the surface of the single-crystal silicon, reducing the density of dangling bonds in the band gap. If more hydrogen is introduced during the deposition process, the hydrogen plasma will etch the deposited film, removing some unstable silicon-hydrogen bonds on the film surface, reducing the defect density in the film, and forming a more stable and ordered microstructure, thus realizing the transformation from an amorphous structure to a nanocrystalline structure. With a further increase in the hydrogen dilution ratio, hydrogen in the hydrogenated amorphous silicon film mainly exists in the form of Si-H2 bonds. These Si-H2 bonds are located at the interface between the amorphous phase and the nanocrystalline phase or at microvoids within the film, reducing the passivation effect on dangling bonds in the amorphous silicon and thus increasing the extinction coefficient K. In subsequent appropriate thermal processes (i.e., steps S121 and S123), hydrogen from the high hydrogen dilution ratio film diffuses into the low hydrogen dilution ratio film. Simultaneously, H gains energy to escape from the trapped state in the film, causing H in the film to transfer to Si-H bonds. Si-H bonds can effectively passivate dangling bonds in amorphous silicon, thereby reducing the extinction coefficient while improving the interface quality between amorphous silicon and the quartz sheet, solving the Bubble Defect problem.
[0081] This application correspondingly provides a superlens. See also Figure 5The superlens includes a substrate 210 and a plurality of columnar microstructures 220. Each columnar microstructure 220 is located on a first main surface (i.e., the front side of the substrate) of the substrate 210, and each columnar microstructure 220 includes a first hydrogenated amorphous silicon layer 222 and a second hydrogenated amorphous silicon layer 224 on the first hydrogenated amorphous silicon layer 222. The first hydrogenated amorphous silicon layer 222 and the second hydrogenated amorphous silicon layer 224 are formed by deposition, and the gas introduced during the deposition process includes hydrogen and a dilution gas. The flow rate ratio of hydrogen to dilution gas introduced during the deposition process of the second hydrogenated amorphous silicon layer 224 is greater than the flow rate ratio of hydrogen to dilution gas introduced during the deposition process of the first hydrogenated amorphous silicon layer 222. Figure 8 This is a perspective view of a superlens in one embodiment of this application.
[0082] In the aforementioned superlens, a hydrogenated amorphous silicon layer deposited at a high hydrogen dilution ratio (i.e., the second hydrogenated amorphous silicon layer 224) is disposed on top of a hydrogenated amorphous silicon layer with a low hydrogen dilution ratio (i.e., the first hydrogenated amorphous silicon layer 222). The hydrogenated amorphous silicon layer with a low hydrogen dilution ratio has better adhesion to the substrate 210, and at the same time, hydrogen outgassing is relatively low (compared to the hydrogenated amorphous silicon layer deposited at a high hydrogen dilution ratio), thus reducing the likelihood of bubble defects and improving the interface quality at the contact between the columnar microstructure 220 and the substrate 210. Furthermore, hydrogen in the hydrogenated amorphous silicon layer with a high hydrogen dilution ratio diffuses into the hydrogenated amorphous silicon layer with a low hydrogen dilution ratio during manufacturing, effectively reducing dangling bonds and defects in the hydrogenated amorphous silicon layer with a low hydrogen dilution ratio, thereby reducing the extinction coefficient and meeting the extinction coefficient requirements of the superlens.
[0083] In one embodiment of this application, the dilution gas is SiH4.
[0084] In one embodiment of this application, the flow ratio of hydrogen to SiH4 introduced during the deposition of the second hydrogenated amorphous silicon layer 224 is 5 to 20, and the flow ratio of hydrogen to SiH4 introduced during the deposition of the first hydrogenated amorphous silicon layer 222 is ≤4.
[0085] In one embodiment of this application, the substrate 210 is a quartz sheet.
[0086] In one embodiment of this application, the thickness of the second hydrogenated amorphous silicon layer 224 is greater than the thickness of the first hydrogenated amorphous silicon layer 222.
[0087] In one embodiment of this application, the n value (refractive index) of each columnar microstructure 220 is 3 to 4.
[0088] In one embodiment of this application, the extinction coefficient K of each columnar microstructure 220 is ≤0.001 at a wavelength of 940nm.
[0089] In one embodiment of this application, the critical dimensions of each columnar microstructure 220 are 100 nanometers to 300 nanometers.
[0090] The superlens and the manufacturing method of the superlens in this application are based on the same inventive concept. For details not specifically described in the superlens, please refer to the above introduction of the manufacturing method of the superlens.
[0091] It should be understood that although the steps in the flowchart of this application are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart of this application may include multiple steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but may be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.
[0092] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.
[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A manufacturing method of a superlens, characterized by, Comprising: forming a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the first hydrogenated amorphous silicon layer on a substrate by deposition; flow ratio of hydrogen gas and dilution gas in the deposition process of forming the second hydrogenated amorphous silicon layer is greater than that in the deposition process of forming the first hydrogenated amorphous silicon layer; patterning the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form a plurality of columnar microstructures; each columnar microstructure comprises a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the first hydrogenated amorphous silicon layer.
2. The manufacturing method of a metalens according to claim 1, wherein The dilution gas is SiH4, the flow ratio of hydrogen gas and SiH4 in the deposition process of forming the second hydrogenated amorphous silicon layer is 5 to 20, and the flow ratio of hydrogen gas and SiH4 in the deposition process of forming the first hydrogenated amorphous silicon layer is ≤4.
3. The manufacturing method of a metalens according to claim 2, wherein The flow of SiH4 in the deposition process is 5sccm to 165sccm.
4. The manufacturing method of a metalens according to claim 1, wherein The step of patterning the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form a plurality of columnar microstructures comprises: forming a sacrificial layer on the second hydrogenated amorphous silicon layer; patterning the sacrificial layer to remove the sacrificial layer directly above the positions where each columnar microstructure is to be formed, forming a plurality of pits; forming a hard mask layer covering the sacrificial layer and the second hydrogenated amorphous silicon layer; removing the hard mask layer above the sacrificial layer, and the hard mask layer in the pits is reserved; removing the remaining sacrificial layer; using the remaining hard mask layer as an etching mask to etch the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer to form each columnar microstructure.
5. The manufacturing method of a metalens according to claim 4, wherein The sacrificial layer is a silicon nitride layer, and the hard mask layer is a silicon dioxide layer.
6. The manufacturing method of a metalens according to claim 4 or 5, wherein The formation of the sacrificial layer and the formation of the hard mask layer are formed by deposition, and the deposition temperature is 400 to 540 degrees Celsius.
7. A metalens, comprising: Comprising: a substrate; a plurality of columnar microstructures on a first main surface of the substrate, each columnar microstructure comprising a first hydrogenated amorphous silicon layer and a second hydrogenated amorphous silicon layer on the first hydrogenated amorphous silicon layer, the first hydrogenated amorphous silicon layer and the second hydrogenated amorphous silicon layer being formed by deposition and the gas introduced in the deposition process comprising hydrogen gas and dilution gas, the flow ratio of hydrogen gas and dilution gas in the deposition process of the second hydrogenated amorphous silicon layer being greater than that in the deposition process of the first hydrogenated amorphous silicon layer.
8. The metalens of claim 7, wherein, The n value of each columnar microstructure is 3 to 4; and / or The extinction coefficient K of each columnar microstructure is ≤0.001 at a wavelength of 940nm.
9. The metalens of claim 7, wherein, The substrate is a quartz wafer.
10. The metalens of claim 7, wherein, The critical dimension of each columnar microstructure is 100nm to 300nm.