Fabrication of polarizers, diffraction gratings and metasurfaces via ion implantation

Abstract

The present disclosure describes the fabrication of polarizers, diffraction gratings, and metasurfaces via ion implantation. The polarizer includes a plurality of non-conductive regions between wire grids of the conductive lines. The conductive wire may include nanowires or nanopillars. The wire grids can be rectangular grids or hexagonal grids.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 471,866, filed on June 8, 2023, entitled “Fabrication of Polarizers, Diffraction Gratings, and Metasurfaces via Ion Implantation,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to the fabrication of polarizers, diffraction gratings, and metasurfaces via ion implantation. Background Art

[0004] By comparing these methods with some aspects of the present method and system set forth in the remainder of this disclosure with reference to the accompanying figures, limitations and disadvantages of existing systems and methods for manufacturing will become apparent to those skilled in the art. Summary of the invention

[0005] Systems and methods for fabricating polarizers, diffraction gratings, and metasurfaces via ion implantation are provided substantially as shown in and / or described in conjunction with at least one of the accompanying drawings, as more fully set forth in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1A Implementations of optical polarizers fabricated via ion implantation according to various example implementations of the present disclosure are shown.

[0007] Figure 1B FIG. 1 shows a schematic diagram of a 3D image ... Figure 1A Optical polarizer.

[0008] Figure 2 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0009] Figure 3 The resulting wire grid polarizer structure, damaged portions removed after wet etching, and resist cleaning are shown according to various example implementations of the present disclosure.

[0010] Figure 4 A specific example of chemically altering the Al material beneath an open resist trench for subsequent removal via stripping is shown according to various example implementations of the present disclosure.

[0011] Figure 5 A specific example of a metal reflective grating generated via an ion implantation-based removal process according to various example implementations of the present disclosure is shown.

[0012] Fig. 6A A top view of a metasurface designed for a 940 nm wavelength according to various example implementations of the present disclosure is shown.

[0013] Figure 6B Various example implementations according to the present disclosure are shown. Fig. 6A Cross-sectional view of the metasurface in .

[0014] Figure 7 A cross-sectional view of another example metasurface according to various example implementations of the present disclosure is shown.

[0015] Figure 8 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0016] Fig. 9 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0017] Fig.10 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0018] Fig.11 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0019] Fig.12 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0020] Fig.13 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0021] Fig.14 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0022] Fig.15 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0023] Fig.16 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0024] Fig.17 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0025] Fig.18 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown.

[0026] Fig.19 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. DETAILED DESCRIPTION

[0027] The present disclosure describes a system and method for fabricating various types of diffraction gratings, metasurfaces, and sub-wavelength structured diffractive optical elements using a variety of different ion implantation techniques.

[0028] Figure 1A Implementations of optical polarizers fabricated via ion implantation according to various example implementations of the present disclosure are shown. Figure 1A In the embodiment of the present invention, a metal layer 103 (such as aluminum (Al)) with a suitable thickness (such as 500nm) is deposited on a substrate 105 of a material that is sufficiently transparent at the wavelength of interest. For polarizer operation in the visible light (>400nm wavelength) to near infrared (<2μm wavelength) band, the substrate 105 can be fused silica, but can also be other suitably transparent materials. A photoresist (PR) 101 is deposited on the Al layer 103 and patterned into a line space pattern with a period that is suitably small compared to the wavelength range of interest so that no diffraction occurs.

[0029] The structure is then ion implanted 107, such as with Ar or other suitable ions, wherein the implanted ions are propagated through the open photoresist trenches into the Al layer 103 and beyond the Al layer 103 into the substrate 105. This process can be performed at room temperature. As the Ar ions 107 propagate through the Al 103, damage occurs in the metal that increases its resistivity to a high or even infinite value, while converting the previously reflective Al layer 103 to a transparent Al (Al 2 O) in the wavelength range of interest. T ) 109. A wire grid polarizer is thus produced, which includes non-conductive / high resistivity Al nanowires 111 between the periodic line space pattern (undamaged regions) T Region 109 (damaged, under open resist space).

[0030] Figure 1B FIG. 1 shows a schematic diagram of a 3D image ... Figure 1A Optical polarizer.

[0031] Figure 2Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Figure 2 In the embodiment of the present invention, oxygen 205 (dimer or monatomic oxygen) is implanted into the Al layer 203 of the polarizer. This method can rely on a resist mask for room temperature implantation, but for any elevated temperatures required during implantation or post-processing steps (such as post-implantation annealing), a hard mask (HM) 207 such as SiN or carbon is required. The oxygen implanted portion of the Al layer is converted to Al during the implantation process itself or in a subsequent annealing step. 2 O 3 If properly designed, Al / Al 2 O 3 Line space structures can be used as polarizers.

[0032] When using N 2 or N instead of O 2 When / O ions are implanted into the aluminum layer 203, aluminum nitride can be formed instead of Al x O y , resulting in different polarizer implementations.

[0033] In a different approach, specific ions can be implanted into the aluminum that cause physical damage or chemical modification, allowing the damaged or chemically altered parts to be subsequently completely selectively removed, such as by a wet etching process. Figure 3 The resulting wire grid polarizer structure, removal of damaged portions 301 after wet etching and resist cleaning are shown according to various example implementations of the present disclosure.

[0034] Figure 4 A specific example of chemically altering the Al material beneath an open resist trench for subsequent removal via stripping according to various example implementations of the present disclosure is shown. Implantation (such as by Si ions 401) occurs at an angle, chemically altering the Al to form Al x Si y compound (black area), which can be removed by wet etching (e.g. using fluoride-based or other chemistries). In this process, the Al surrounded by the converted area will simply be stripped off, resulting in Figure 3 Structure shown. It should be noted that the implant angle (as shown by the arrows) can be varied and used to affect the size of the remaining lines (e.g., narrower or wider). This technique is useful in cases where the desired Al lines are thinner than those dictated by the potentially limited range of available resist sizes.

[0035] Figure 5A specific example of a metal reflective grating generated via an ion implantation-based removal process according to various example implementations of the present disclosure is shown. If the layer to be implanted is Al or another metal, and the period of the pattern is large enough to allow diffraction, a metal reflective grating 501 can be designed and manufactured, provided that a sufficiently thick metal layer 503 is retained under the stripped portion of the groove.

[0036] The previous discussion has focused on creating polarizers and diffractors based on the removal or chemical / physical modification of conductive layers. Similar considerations apply if the layer to be processed by ion implantation is a dielectric material that is transparent at the wavelength of interest. By ion implantation, it is possible to create a supporting material change and subsequent removal of a transmission grating.

[0037] Fig. 6A A top view of a metasurface designed for a 940 nm wavelength according to various example implementations of the present disclosure is shown. Figure 6B Various example implementations according to the present disclosure are shown. Fig. 6A A cross-sectional view of the metasurface in . Fig. 6A and Figure 6B In the example, a properly designed two-dimensional resist pattern (such as nanopillars 601 on a hexagonal or rectangular grid with sub-wavelength dimensions) is transferred into the dielectric layer via ion implantation. Metasurface materials that support designs (e.g., lenses, dot generators, etc.) can be generated.

[0038] exist Fig. 6A and Figure 6B In the present invention, a metasurface structure is created by defining sub-wavelength scale regions of high and low refractive index. Through lateral feature size (diameter) control, the unit cell filled with surrounding medium (air, low refractive index region) containing high refractive index nanorods 601 produces arbitrary phase delay, which can be designed to provide a global phase surface with desired functions such as lens, splitter, etc. The material removal of the air-filled portion of the unit cell to produce the sub-wavelength scale can be performed as discussed above, see Figure 4 .

[0039] Alternatively, after a material change (specifically, a change in an optical material property, such as a refractive index), a high refractive index region 601 (such as a silicon dioxide layer) may be produced by implanting appropriate ions (such as Ge, etc.) into a suitable host dielectric layer (such as silicon dioxide). Fig. 6A and Figure 6B A supersurface with nanopillars in the . Figure 7 A cross-sectional view of another example metasurface according to various example implementations of the present disclosure is shown.

[0040] Figure 7The metasurface of is produced by implanting ions into openings 703 in a (negative) photoresist. The photoresist defines the cross-section of the high refractive index nanofeatures 701. Since the refractive index contrast between the nanostructures thus generated in the solid host material is usually lower than that of air, the thickness of the host material metasurface layer 705 may need to be appropriately adjusted.

[0041] A wire grid polarizer can be formed by ion implantation into the film using a patterned periodic grating mask. In one embodiment, the deposited film is conductive and the implanted region is resistive, such as an aluminum film implanted with oxygen or nitrogen ions. The resistivity of the implanted region can be controlled by the implanted dose, and the depth of penetration into the film can be controlled by the implantation energy.

[0042] Figure 8 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Figure 8 In the process, multi-stage implantation with different energies and depths (h) is used to implant silicon dioxide (SiO 2 ) on the substrate 803 x )A single layer 801 of Al grating layer is produced in the film.

[0043] Fig. 9 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig. 9 middle, Figure 8 The structure is encapsulated with a dielectric film 901. The dielectric 901 may be spun or deposited using a technique such as chemical vapor deposition (CVD).

[0044] Fig.10 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.10 In the , another layer 801 is added to Fig. 9 The structure of AlO can be repeated many times. x Film deposition is followed by Al implantation to produce multiple layers 801 .

[0045] Fig.11 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.11 In the embodiment, a sealant layer 901 is added to Fig.10 One or more sealant layers 901 may be present.

[0046] Fig.12 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.12In the AlO x The film deposition is repeated multiple times in succession to produce multiple layers 801, 1201. During the implantation process, implants from the top layer 801 may diffuse into the lower layer 1201.

[0047] Fig.13 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.13 In the embodiment, a sealant layer 901 is added to Fig.12 in the structure.

[0048] Fig.14 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.14 In the embodiment, the sealant layer 901 is placed between the multiple layers 801, 1201.

[0049] Fig.15 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.15 In the embodiment, a sealant layer 901 is added to Fig.14 in the structure.

[0050] Fig.16 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. In an alternative flow, a dielectric film is deposited and a grating is formed by ion implanting dopants using a patterned periodic grating mask. Multi-level implantation is used to create a layer 1601 comprising alternating doped and undoped regions.

[0051] Fig.17 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.17 In the embodiment, the sealant layer 901 of the electrolyte membrane is added to Fig.16 in the structure.

[0052] Fig.18 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.18 About Fig.16 The described process is repeated multiple times in succession to produce multiple layers 1601, 1801. During the implantation process, implants from the top layer 1601 may diffuse into the lower layer 1801.

[0053] Fig.19 Another embodiment of an optical polarizer fabricated via ion implantation according to various example implementations of the present disclosure is shown. Fig.19In the embodiment, a sealant layer 901 is added to Fig.18 In any embodiment (for example, Figures 8 to 19 ) can include an anti-reflection coating in the deposition to help mitigate projection losses.

[0054] As used herein, the terms "circuit" and "circuitry" refer to physical electronic components (i.e., hardware) and any software and / or firmware ("code") that can configure hardware, be executed by hardware, and / or be otherwise associated with hardware. As used herein, for example, a particular processor and memory may include a first "circuit" when executing a first line or more lines of code, and include a second "circuit" when executing a second line or more lines of code. As used herein, "and / or" refers to any one or more items in a list connected by "and / or". For example, "x and / or y" represents any element in a three-element set {(x), (y), (x, y)}. For another example, "x, y, and / or z" refers to any element in a seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. As used herein, the term "exemplary" refers to an example, instance, or illustration as a non-limiting example. As used herein, the terms "such as" and "for example" lead to a list of one or more non-limiting examples, instances, or diagrams. As used herein, a circuit system is "operable" to perform a function, whether or not performance of the function is disabled or not enabled (e.g., by a user-configurable setting, factory trimming, etc.), as long as the circuit system includes the hardware and code (if any is necessary) required to perform the function. As used herein, the term "based on" means "based at least in part on." For example, "x based on y" means that "x" is based at least in part on "y" (e.g., may also be based on z).

[0055] Although the present method and / or system has been described with reference to certain implementations, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and / or system. In addition, many modifications may be made to adapt particular circumstances or materials to the teachings of the present disclosure without departing from the scope of the present disclosure. Therefore, the present method and / or system is not intended to be limited to the specific implementations disclosed, but rather the present method and / or system will include all implementations falling within the scope of the appended claims.

Claims

1. A structure fabricated by ion implantation, comprising: A polarizer includes a plurality of non-conductive regions between a grid of conductive elements.

2. The structure according to claim 1, wherein: The conductive elements include nanowires.

3. The structure according to claim 1, wherein: The conductive elements include nanopillars.

4. The structure according to claim 1, wherein: The grid is a hexagonal grid.

5. The structure according to claim 1, wherein: The grid is operably coupled to the substrate.

6. The structure according to claim 5, wherein: The substrate includes a silicon dioxide compound.

7. The structure according to claim 5, wherein: The substrate is transparent at the wavelength of interest.

8. The structure according to claim 7, wherein: The wavelength of interest is greater than 400 nm and less than 2 μm.

9. The structure according to claim 1, wherein: The grid comprises aluminum.

10. The structure according to claim 1, wherein: The non-conductive region includes transparent aluminum.

11. The structure according to claim 1, wherein: The non-conductive region is generated by ion implantation of a conductive material.

12. The structure according to claim 11, wherein: The ion implantation includes using argon, oxygen, germanium and / or nitrogen.

13. The structure according to claim 11, wherein: The grid is created during ion implantation by covering the conductive material with photoresist in a periodic line-space pattern.

14. The structure according to claim 1, wherein: The non-conductive region includes aluminum nitride.

15. The structure of claim 1, wherein: The non-conductive region is created by implanting silicon ions at an angle to produce an aluminum silicon compound.

16. The structure according to claim 15, wherein: The aluminum-silicon compound is removed via a stripping process.

17. The structure of claim 15, wherein: The aluminum silicon compound is removed via wet etching.

18. The structure of claim 15, wherein: The angle determines the size of the conductive element.

19. The structure of claim 1, wherein: The grid is operably coupled to the metal layer.

20. The structure of claim 1, wherein: The grid comprises a plurality of columns, and The distance between each column is determined based on the wavelength of interest.

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