Polarizer, diffraction grating and meta surface fabrication via ion implantation

Abstract

To provide fabrication of a polarizer, a diffraction grating and a meta surface via ion implantation.SOLUTION: The polarizer comprises a plurality of non-conducting areas between conducting wires of a wire grid. The conducting wires may comprise nanowires or nanopillars. The wire grid may be a rectangular or hexagonal grid.SELECTED DRAWING: Figure 1A

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 471,866, filed June 8, 2023, entitled "POLARIZER DIFFRACTION GRATING AND META SURFACE FABRICATION VIA ION IMPLANTATION," the disclosure of which is incorporated herein in its entirety.

[0002]

[0002] The limitations and drawbacks of conventional systems and methods for manufacturing will become apparent to those skilled in the art through a comparison of such approaches with certain aspects of the present methods and systems described in the remainder of this disclosure with reference to the drawings. Summary of the Invention

[0003]

[0003] Systems and methods for the fabrication of polarizers, diffraction gratings, and metasurfaces by ion implantation are provided substantially as illustrated and / or described in connection with at least one of the drawings, as more fully described in the claims. [Brief description of the drawings]

[0004] [Figure 1A] FIG. 1A illustrates an embodiment of an optical polarizer fabricated by ion implantation in accordance with various exemplary implementations of the present disclosure. [Figure 1B]

[0005] FIG. 1B illustrates the optical polarizer of FIG. 1A after photoresist removal, according to various exemplary implementations of the present disclosure. [Diagram 2]

[0006] FIG. 2 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Diagram 3]

[0007] FIG. 3 illustrates the resulting wire grid polarizer structure after wet etching, damage removal, and resist cleanup, according to various exemplary implementations of the present disclosure. [Figure 4]

[0008] FIG. 4 illustrates a specific example of chemically altering the Al material beneath the bare resist trenches for subsequent removal by lift-off, according to various exemplary implementations of the present disclosure. [Diagram 5]

[0009] FIG. 5 illustrates a particular example of a metallic reflective grating produced via an ion implantation-based removal process, in accordance with various exemplary implementations of the present disclosure. [Figure 6A]

[0010] FIG. 6A is a top view of a metasurface designed for a wavelength of 940 nm, in accordance with various exemplary implementations of the present disclosure. [Figure 6B]

[0011] FIG. 6B is a cross-sectional view of the metasurface of FIG. 6A, according to various exemplary implementations of the present disclosure. [Figure 7]

[0012] FIG. 7 is a cross-sectional view of another exemplary metasurface, according to various exemplary embodiments of the present disclosure. [Figure 8]

[0013] FIG. 8 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 9]

[0014] FIG. 9 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 10]

[0015] FIG. 10 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 11]

[0016] FIG. 11 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 12]

[0017] FIG. 12 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 13]

[0018] FIG. 13 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 14]

[0019] FIG. 14 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 15]

[0020] FIG. 15 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 16]

[0021] FIG. 16 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 17]

[0022] FIG. 17 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 18]

[0023] FIG. 18 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. [Figure 19]

[0024] FIG. 19 illustrates another embodiment of an optical polarizer fabricated by ion implantation, in accordance with various exemplary implementations of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005]

[0025] This disclosure describes systems and methods for fabricating various types of gratings, metasurfaces, and sub-wavelength structured diffractive optical elements using a number of different ion implantation techniques.

[0006]

[0026] FIG. 1A shows an embodiment of an optical polarizer fabricated by ion implantation according to various exemplary implementations of the present disclosure. In FIG. 1A, a metal layer 103, e.g., aluminum (Al), of suitable thickness, e.g., 500 nm, is deposited on a substrate 105 of a material that is sufficiently transparent at the wavelengths of interest. For polarizer operation in the wavelength range from visible (>400 nm wavelength) to near infrared (<2 μm wavelength), the substrate 105 may be fused silica, although other suitable transparent materials are possible. Photoresist (PR) 101 is deposited on the Al layer 103 and patterned into a line-space pattern with a period appropriately small compared to the wavelength range of interest so that no diffraction occurs.

[0007]

[0027] The structure is then ion implanted 107, for example with Ar or other suitable ions, which propagate through the exposed photoresist trenches into the Al layer 103 and across the Al layer 103 into the substrate 105. This process occurs at room temperature. As the Ar ions 107 propagate through the Al layer 103, damage is caused to the metal, increasing its resistivity to a high or even infinite value, while at the same time the previously reflective Al layer 103 becomes transparent Al (Al T ) 109, which results in non-conductive / highly resistive Al nanowires 111 (under the damaged, bare resist spaces) between the periodic line-space pattern of conductive Al nanowires 111 (undamaged areas). T A wire grid polarizer with regions 109 is produced.

[0008]

[0028] FIG. 1B illustrates the optical polarizer of FIG. 1A after photoresist removal, according to various exemplary implementations of the present disclosure.

[0029] FIG. 2 illustrates another embodiment of an optical polarizer fabricated by ion implantation according to various exemplary implementations of the present disclosure. In FIG. 2, the Al layer 203 of the polarizer is implanted with oxygen 205 (dimeric or monoatomic oxygen). The method can rely on a resist mask for room temperature implantation, but a hard mask (HM) 207 such as SiN or carbon is required for the elevated temperatures required for implantation or subsequent process steps such as post-implant annealing. Either during the implantation process itself or in a subsequent annealing step, the oxygen-implanted portion of the Al layer is converted to Al2O3. The Al / Al2O3 line-space structure functions as a polarizer if properly designed.

[0009]

[0030] Ion implantation of aluminum layer 203 with N2 or N instead of O2 / O can form aluminum nitride instead of AlxOy, resulting in different polarizer embodiments.

[0010]

[0031] In another approach, aluminum can be implanted with specific ions that induce physical damage or chemical modification, allowing for subsequent complete selective removal of the damaged or chemically altered portions, for example, by a wet etching process. Figure 3 shows the resulting wire grid polarizer structure after wet etching and removal of the damaged portions 301 and cleanup of the resist, according to various exemplary implementations of the present disclosure.

[0011]

[0032] FIG. 4 illustrates a specific example of chemically altering the Al material beneath the bare resist trench for subsequent removal by lift-off, according to various exemplary implementations of the present disclosure. Implantation, for example with Si ions 401, occurs at an angle to chemically alter the Al to form AlxSiy compounds (black regions), which can be removed by wet etching, for example using fluoride-based or other chemistries. The Al surrounded by the transformed regions is simply lifted off during the process, forming the structure shown in FIG. 3. Note that the implant angle (indicated by the arrows) can be varied and used to affect the dimensions of the remaining lines, for example narrowing or widening. This technique is useful when the desired Al lines are thinner than dictated by the limited range of available resist dimensions.

[0012]

[0033] 5 shows a specific example of a metallic reflective grating produced via an ion implantation-based removal process according to various exemplary implementations of the present disclosure. If the implanted layer is Al or other metal, and the period of the pattern is large enough to allow diffraction, a metallic reflective grating 501 can be designed and fabricated, provided that a sufficiently thick metallic layer 503 remains beneath the lifted-off portion of the trench.

[0013]

[0034] The discussion so far has focused on the creation of polarizers and diffractors based on the removal or modification by chemical / physical modification of a conductive layer. Similar considerations apply when the layer treated by ion implantation is a dielectric material that is transparent at the wavelength of interest. Ion implantation allows for a modification of the material, the subsequent removal of which can create a transmission grating.

[0014]

[0035] FIG. 6A shows a top view of a metasurface designed for a wavelength of 940 nm according to various exemplary implementations of the present disclosure. FIG. 6B shows a cross-sectional view of the metasurface of FIG. 6A according to various exemplary implementations of the present disclosure. In FIG. 6A and FIG. 6B, a properly designed two-dimensional resist pattern, e.g., nanopillars 601 on a hexagonal or rectangular grid with sub-wavelength dimensions, is transferred to a dielectric layer by ion implantation. As an example, metasurface materials that enable the design of lenses, dot generators, etc. can be produced.

[0015]

[0036] In Figures 6A and 6B, the metasurface structure is created by defining subwavelength scale regions of high and low refractive index. A unit cell filled with the surrounding medium (air, low refractive index region) containing high index nanopillars 601 produces an arbitrary phase retardation that can be engineered into the overall phase surface providing a desired function such as lensing, splitting, etc. through lateral feature size (diameter) control. Material removal to create the air-filled portion of the subwavelength scale unit cell can proceed as described above with reference to Figure 4.

[0016]

[0037] Alternatively, following material modification (specifically, modification of optical material properties such as refractive index), a metasurface having high refractive index regions 601 (such as the nanopillars of FIG. 6) can be created by implantation of suitable ions, such as Ge, in a suitable host dielectric layer such as silicon dioxide. FIG. 7 shows a cross-sectional view of another exemplary metasurface according to various exemplary embodiments of the present disclosure.

[0017]

[0038] The metasurface of Figure 7 is created by implanting ions into openings 703 in (negative) photoresist. The photoresist defines the cross-sections of high refractive index nanofeatures 701. Because the refractive index contrast between nanostructures thus created in a solid host material is typically low compared to air, the thickness of the host material metasurface layer 705 may require appropriate adjustment.

[0018]

[0039] Wire grid polarizers can be formed by ion implantation into a film using a patterned periodic grating mask. In one embodiment, the deposited film is conductive and the implanted regions are resistive, such as an aluminum film implanted with oxygen or nitrogen ions. The resistivity of the implanted regions can be controlled by the implantation dose, and the penetration depth into the film can be controlled by the implantation energy.

[0019]

[0040] 8 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In FIG. 8, a single layer of Al lattice layer 801 is created in an aluminum oxide (AlOx) film on a silicon dioxide (SiO2) substrate 803 using multi-step implants targeted to different energies and depths (h).

[0020]

[0041] Figure 9 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In Figure 9, the structure of Figure 8 is encapsulated with a dielectric film 901. The dielectric 901 may be spun on or deposited using techniques such as chemical vapor deposition (CVD).

[0021]

[0042] 10 illustrates another embodiment of an optical polarizer fabricated by ion implantation according to various exemplary implementations of the present disclosure. In FIG. 10, another layer 801 is added to the structure of FIG. 9. The deposition of an AlOx film followed by Al implantation can be repeated multiple times to create multiple layers 801.

[0022]

[0043] Figure 11 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In Figure 11, an encapsulation layer 901 is added to the structure of Figure 10. There can be one or more encapsulation layers 901.

[0023]

[0044] 12 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In FIG. 12, deposition of an AlOx film followed by Al implantation is repeated multiple times in succession to create multiple layers 801, 1201. The implant from the top layer 801 may diffuse into the lower layer 1201 during the implantation process.

[0024]

[0045] 13 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure, in which an encapsulation layer 901 has been added to the structure of FIG.

[0025]

[0046] 14 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In FIG. 14, an encapsulation layer 901 is disposed between multiple layers 801, 1201.

[0026]

[0047] 15 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In FIG. 15, an encapsulation layer 901 is added to the structure of FIG.

[0027]

[0048] 16 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In an alternative process, a dielectric film is deposited and a grating is formed by ion implantation of dopants using a patterned periodic grating mask. A multi-step implant is used to create a layer 1601 with alternating doped and undoped regions.

[0028]

[0049] 17 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure, in which an encapsulation layer 901 of dielectric film is added to the structure of FIG.

[0029]

[0050] Figure 18 illustrates another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In Figure 18, the process described with respect to Figure 16 is repeated multiple times in succession to create multiple layers 1601, 1801. Implants from the top layer 1601 may diffuse into the underlying layer 1801 during the implantation process.

[0030]

[0051] Figure 19 shows another embodiment of an optical polarizer fabricated by ion implantation, according to various exemplary implementations of the present disclosure. In Figure 19, an encapsulation layer 901 has been added to the structure of Figure 18. Any of the embodiments (e.g., as shown in Figures 8-19) may include an anti-reflective coating during deposition to help reduce transmission losses.

[0031]

[0052] As used herein, the terms "circuitry" and "circuitry" refer to physical electronic components (i.e., hardware) and any software and / or firmware ("code") that may comprise, be executed by, or otherwise be associated with the hardware. As used herein, by way of example, a particular processor and memory may comprise a first "circuitry" when it executes one or more lines of a first code, and a second "circuitry" when it executes one or more lines of a second code. As used herein, "and / or" means any one or more items in a list joined by "and / or". As an example, "x and / or y" means any element of the 3-element set {(x),(y),(x,y)}. As another example, "x,y and / or z" means any element of the 7-element set {(x),(y),(z),(x,y),(x,z),(y,z),(x,y,z)}. As used herein, the term "exemplary" means to serve as a non-limiting example, instance, or illustration. As used herein, the terms "for example" and "by way of example" constitute a list of one or more non-limiting examples, instances, or illustrations. As used herein, circuitry is "operable" to perform a function whenever it comprises the necessary hardware and code (if necessary) to perform that function, regardless of whether performance of that function has been disabled or enabled (e.g., by a user-configurable setting, a factory trim, etc.). As used herein, the term "based on" means "based at least in part on." For example, "x based on y" means that "x" is at least in part based on "y" (and may also be based on z, by way of example).

[0032]

[0053] Although the method and / or system have been described with reference to particular implementations, it will be understood by those skilled in the art that various modifications may be made and equivalents may be substituted without departing from the scope of the method and / or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its scope. Therefore, the method and / or system is not limited to the particular implementations disclosed, but it is intended that the method and / or system include all implementations falling within the scope of the appended claims.

Claims

1. A structure comprising: Polarizer including a plurality of non-conductive regions between a grid of conductive elements - Patent 7233635 A structure equipped with.

2. The structure of claim 1 , wherein the conductive element comprises a nanowire.

3. The structure of claim 1 , wherein the conductive elements comprise nanopillars.

4. 2. The structure of claim 1, wherein the grid is a hexagonal grid.

5. The structure of claim 1 , wherein the grid is operably coupled to a substrate.

6. The structure of claim 5 , wherein the substrate comprises a silica compound.

7. 6. The structure of claim 5, wherein the substrate is transparent at a wavelength of interest.

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

9. 10. The structure of claim 1, wherein the grid comprises aluminum.

10. 10. The structure of claim 1, wherein the non-conductive region comprises transparent aluminum.

11. 2. The structure of claim 1, wherein the non-conductive regions are created by ion implantation into a conductive material.

12. 12. The structure of claim 11, wherein the ion implantation includes the use of one or more of argon, oxygen, germanium, and nitrogen.

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

14. 10. The structure of claim 1, wherein the non-conductive region comprises aluminum nitride.

15. 2. The structure of claim 1, wherein the non-conductive regions are created by implanting silicon ions at an angle to create an aluminum silicide.

16. 16. The structure of claim 15, wherein the aluminum silicide is removed by a lift-off process.

17. 16. The structure of claim 15, wherein the aluminum silicide is removed by a wet etch.

18. 16. The structure of claim 15, wherein the angle determines a dimension of the conductive element.

19. 10. The structure of claim 1, wherein the grid is operatively coupled to a metal layer.

20. 2. The structure of claim 1, the grid includes a plurality of pillars; The distance between each pillar is determined according to the wavelength of interest. structure.

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