Optical component and image sensor comprising an optical component

Abstract

This invention discloses, in an exemplary embodiment, an optical component including a dielectric structure having a substantially rectangular cross-section and upper and lower surfaces. A first conductive layer is disposed on the upper surface, wherein the first conductive layer has a first opening positioned to receive incident electromagnetic radiation. A second conductive layer has a second opening positioned, for example, toward a CMOS sensor pixel in a silicon substrate to emit electromagnetic radiation. The dimensions of the optical component are configured to provide constructive interference for incident radiation of a selected wavelength.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to European patent application No. EP20305871, filed on July 30, 2020, entitled “OPTICAL COMPONENT AND IMAGESENSOR COMPRISING AN OPTICAL COMPONENT”, which is incorporated herein by reference in its entirety. Background Technology

[0003] This section is intended to introduce the reader to various aspects of the art that may relate to the various aspects of this disclosure described below and / or claimed. This discussion is intended to help provide the reader with background information to facilitate a better understanding of the various aspects of the systems and methods described herein. Therefore, it should be understood that these statements should be interpreted in this context, rather than as an admission of prior art.

[0004] This disclosure relates to the field of CMOS sensors. Some CMOS sensors operate based on the photoelectric effect, which converts incident photons into electrical charges, thereby generating a voltage (using integrated electronics) that varies with light intensity. Some CMOS sensors operate at near-infrared (NIR) wavelengths. Such NIR CMOS sensors have gradually gained market share and are replacing potentially expensive and less efficient traditional CCD sensors. CMOS NIR sensors are used in digital cameras to acquire data under poor lighting conditions (e.g., nighttime traffic management). Such sensors are also used in security applications, personal authentication applications, and ranging applications.

[0005] In practice, image sensors use microlenses to focus incident radiation onto the photosensitive portion of the device, which is typically a semiconductor substrate such as silicon. Silicon has a low absorption coefficient, which necessitates a thick photon absorption layer, thereby increasing chip costs, as the fabrication of thick-substrate CMOS sensors utilizes expensive manufacturing equipment.

[0006] Conventional CMOS sensors consist of microlenses and a photosensitive component that converts received photons into electrons. However, this optical stack lacks the filtering capability to allow only a limited band of wavelengths centered at one wavelength to pass through and reach the photodetector. Therefore, some sensors also use color filter layers.

[0007] Wavelength-selective absorption has been proposed in the literature using techniques such as diffractive light-trapping pixels, silicon nanowires with hexagonal cross-sections, and III-V semiconductor nanowires. Such systems typically require complex and expensive fabrication techniques. Summary of the Invention

[0008] The terms "an embodiment," "implementation," or "exemplary embodiment" used in the specification describe embodiments that may include specific features, structures, or characteristics; however, not every embodiment necessarily includes specific features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in conjunction with an embodiment, such feature, structure, or characteristic may be used in conjunction with other embodiments, whether or not it is explicitly described.

[0009] An optical component according to some embodiments includes: a dielectric structure having at least one side surface, an upper surface, and a lower surface, the at least one side surface being open to receive incident electromagnetic radiation; a first conductive layer on the upper surface having a first opening positioned to receive incident electromagnetic radiation; and a second conductive layer on the lower surface having a second opening positioned to emit electromagnetic radiation.

[0010] In some implementations, the cross-section of the dielectric structure is substantially rectangular.

[0011] In some implementations, the first opening and the second opening have substantially the same width.

[0012] In some implementations, the first opening and the second opening are substantially centered on the dielectric structure.

[0013] In some embodiments, the dielectric structure is mounted on a silicon substrate, and the second opening is positioned to emit electromagnetic radiation into the silicon substrate.

[0014] Some implementations also include a photodetector located beneath the dielectric structure.

[0015] In some implementations, the dielectric structure has a height h between 1600 nm and 1900 nm. 元件 and the width d between 1100nm and 1400nm 元件 .

[0016] In some implementations, the dielectric structure has a height h between 900 nm and 1300 nm. 元件 and the width d between 750nm and 1050nm 元件 .

[0017] In some implementations, the first opening and the second opening each have a width between 150 nm and 200 nm.

[0018] In some embodiments, the optical component is configured to selectively transmit light with wavelength λ. inc The incident electromagnetic radiation, wherein the height h of the dielectric structure元件 Basically equal to Where n H It is the refractive index of the dielectric structure and n L It is the refractive index of the surrounding medium.

[0019] In some embodiments, the optical component is configured to selectively transmit light with wavelength λ. inc The incident electromagnetic radiation, wherein the width d of the dielectric structure 元件 Not less than

[0020]

[0021] in And where n H It is the refractive index of the dielectric structure and n L It is the refractive index of the surrounding medium.

[0022] In some implementations, the dielectric structure is configured such that for a selected wavelength λ inc The electromagnetic radiation, through the first opening and the wave entering the dielectric structure through the side surface, undergoes constructive interference at the second opening.

[0023] An image sensor according to some embodiments includes a two-dimensional array of optical components as described herein.

[0024] One method according to some embodiments includes directing electromagnetic radiation onto an optical component, wherein the optical component includes: a dielectric structure having at least one side surface, an upper surface, and a lower surface, the at least one side surface being open to receive incident electromagnetic radiation; a first conductive layer on the upper surface having a first opening positioned to receive incident electromagnetic radiation; and a second conductive layer on the lower surface having a second opening positioned to emit electromagnetic radiation.

[0025] In some implementations of this method, the height h of the dielectric structure 元件 Basically equal to Where n H It is the refractive index of the dielectric structure and n L It is the refractive index of the surrounding medium.

[0026] In some embodiments of this method, the width d of the dielectric structure 元件 Not less than

[0027]

[0028] in And where n H It is the refractive index of the dielectric structure and nL It is the refractive index of the surrounding medium.

[0029] Some implementations also include operating a photodetector to detect the amount of electromagnetic radiation emitted through the second opening.

[0030] In some embodiments, an optical component includes a dielectric structure having a substantially rectangular cross-section and an upper surface and a lower surface; a first conductive layer on the upper surface having a first opening positioned to receive incident electromagnetic radiation; and a second conductive layer on the lower surface having a second opening positioned to emit electromagnetic radiation.

[0031] In some embodiments, the first opening and the second opening each have a width smaller than the width (d) of the dielectric structure. 元件 The width (w) of ).

[0032] In some implementations, the first opening and the second opening have substantially the same width.

[0033] In some implementations, the first opening and the second opening are substantially centered on the dielectric structure.

[0034] In some implementations, the optical component is mounted on a silicon substrate or another substrate of photosensitive material.

[0035] Some implementations also include a photodetector located beneath the dielectric structure. This photodetector may be a pixel of a CMOS image sensor.

[0036] In some embodiments, the dielectric structure has at least one side surface configured to receive incident electromagnetic radiation.

[0037] In some implementations, the dielectric structure includes a photopolymer.

[0038] In some implementations, these conductive layers are metal layers. Attached Figure Description

[0039] Figure 1 The spectral dependence of optical power in a silicon substrate is shown, demonstrating the wavelength selectivity (λ) of the exemplary embodiment. inc =939.8nm) light absorption capacity.

[0040] Figure 2 This is a cross-sectional schematic diagram of an optical component unit according to some implementation schemes.

[0041] Figures 3A to 3B The photoresist considered during the simulation is shown. Figure 3A ) and silicon ( Figure 3BExemplary dispersion characteristics of the refractive index and extinction coefficient of ).

[0042] Figure 4 This is a schematic cross-sectional view of the simulated power distribution in some implementations for the case of two dielectric edges irradiated by a plane wave.

[0043] Figures 5A to 5B Edge diffraction waves are formed by optical elements with conductive layers. Figure 5A ) and spherical waves ( Figure 5B A schematic diagram of ).

[0044] Figures 6A to 6D This is a schematic cross-sectional view showing different configurations of an optical element with varying positions of the conductive layer and the openings therein.

[0045] Figures 7A to 7B It is shown Figure 6A Figure 7D shows the spectral variation of optical power in silicon for the optical element.

[0046] Figure 8 This is a schematic cross-sectional view showing the configuration of optical elements according to some embodiments.

[0047] Figure 9 It is shown Figure 8 A graph showing the spectral variation of optical power in silicon with a geometric configuration, wherein the top and bottom surfaces of the dielectric element have openings of equal width (=200nm) located in the conductive layer.

[0048] Figure 10 It is for λ inc =940nm, for unit cell width d=2300nm and PEC slit width w=400nm, for h 元件 and d 元件 A schematic visualization of simulated optical power in silicon substrates with different values.

[0049] Figure 11 It shows the use Figure 10 The graph shows the spectral dependence of the system parameters around region I on the optical power in silicon at normal incidence.

[0050] Figure 12 It shows the corresponding Figure 10 The graph shows the spectral variation of optical power in silicon at different incident angles for different physical parameters of region I.

[0051] Figure 13 This shows a size of d = 2050 nm, d 元件 =690nm, h 元件 A graph showing the simulated spectral variation of optical power in silicon unit cells with wavelengths of 1085 nm and 200 nm.

[0052] Figures 14A to 14C This illustrates the optical components according to some embodiments for the polar resonant wavelength. Figure 14A and Figure 14C ) and resonant wavelength ( Figure 14B The optical power is redistributed.

[0053] Figure 15 This is a graph showing the spectral variation of optical power in silicon for incident light at different angles.

[0054] Figure 16 It is a graph showing the full width at half maximum (FWHM) of the optical power peak at 940 nm, which varies with the incident angle in an exemplary embodiment.

[0055] Figure 17 This is a graph showing the spectral variation of optical power in silicon for different opening widths w in the conductive layer.

[0056] Figure 18 This is a graph showing the effect of the width of the opening in the conductive layer on the spectral position of the center wavelength.

[0057] Figure 19 This is a graph showing the effect of the width of the opening in the conductive layer on the FWHM of the corresponding peak.

[0058] Figures 20A to 20F This is a schematic top view of an exemplary optical component according to some implementation schemes.

[0059] Figure 21 This is a cross-sectional schematic diagram of an optical component unit according to some implementation schemes. Detailed Implementation

[0060] Some implementation schemes operate to improve performance in conventional silicon substrates for a given incident wavelength λ inc Optical absorption of incident light. In some embodiments, the incident wavelength λ inc =940nm. Configured for λ inc Image sensors with a wavelength of 940nm can be applied, for example, to machine vision cameras used for rapid inspection in manufacturing / production sites. They can also be used in automotive LiDAR or biometric applications to support iris recognition and finger vein biometrics. However, the implementations described herein are not limited to any particular sensor application. Some examples in this document are described as being for near-infrared (NIR) radiation. This type of radiation and other electromagnetic radiation are referred to herein as "light," regardless of whether it is visible to humans.

[0061] Some embodiments provide a device design that selectively enhances the concentration of incident light radiation for a selected wavelength in the photosensitive portion of the device, thereby increasing its optical absorption and thus its sensitivity. The remaining incident wavelengths are reflected back into the incident medium.

[0062] Some implementations use a selected incident wavelength (e.g., λ). inc The wavelength band centered at 940 nm provides relatively high photodetection, while offering relatively low photodetection for other wavelengths. Some implementations are achieved without using a focusing microlens located on top of the photodetector. Some implementations can be used in applications that would otherwise require complex multilayer spectral IR filters. Some implementations can be achieved without microstructures containing semiconductor material.

[0063] Some implementations use a topology design with periodic unit cells, which are used for a range of incident angles (e.g., θ). inc =±5°) for the selected wavelength (such as λ) inc A focused optical hotspot is generated centered at a wavelength of 939.8 nm and emitted into a silicon photodetector below. The unit cell is operable to reflect other incident light. In some embodiments, the full width at half maximum (FWHM) of the band is approximately 114.5 nm, and the center wavelength has at least 1.92 times the optical power compared to the remaining incident wavelengths. Figure 1 As shown, this type of implementation can increase the number of charge carriers generated by photons in the photodetector for that wavelength band, which in turn provides increased sensitivity of the entire system for the corresponding wavelength band.

[0064] Figure 1 The spectral dependence of the light power emitted into the silicon substrate is shown, demonstrating the wavelength selectivity (λ) of the exemplary embodiment. inc =939.8nm) light absorption capacity.

[0065] In some implementations, spectral dependence is achieved by employing edge diffraction waves formed from different edges of the unit element and combining them with spherical waves such that their constructive interference produces strong optical hotspots for a fixed wavelength at a desired spatial location in the near field.

[0066] Figure 2 This is a schematic cross-sectional view of a unit cell designed to selectively enhance the power of light emitted into a silicon substrate for a selected incident wavelength. Figure 2 This is a schematic cross-sectional view of a unit cell 200 according to some implementation schemes. The unit cell 200 includes a dielectric element 202 with a rectangular cross-section. The dielectric element 202 has a refractive index n. H And the immersion refractive index is n LThe element 202 is placed in the surrounding medium (e.g., air). The element 202 may be made of a commercially available polymeric photoresist (such as Microchem 495 PMMA). The element 202 may be disposed on a silicon substrate 204. The silicon substrate 204 may include a CMOS sensor or other photodetector.

[0067] Conductive layers 206 and 208, which may be metal layers, are disposed above and below the rectangular element 202. Conductive layers 206 and 208 include corresponding openings 210 and 212. As discussed in more detail below, the width of the openings can be selected to provide filtering of incident light to primarily allow the desired wavelength (e.g., λ). inc =940nm) reaches the silicon photodetector.

[0068] In the simulations discussed herein, the conductive layer is treated as a perfect electrical conductor (PEC). The conductive layer may therefore be referred to herein as a PEC layer, but it should be understood that in practical implementations, the conductive layer may have a small but non-zero resistance. Furthermore, perfectly matched layer (PML) boundary conditions are used to perform the simulations to avoid non-physical reflection effects.

[0069] Figures 3A to 3B The photoresist considered during the simulation is shown. Figure 3A ) and silicon ( Figure 3B Exemplary dispersion characteristics of the refractive index and extinction coefficient of ).

[0070] In an exemplary embodiment, multiple unit cells similar to unit 200 are arranged in a Froquette periodic manner under boundary conditions. and Periodically arranged. For a given material property, the optical response of the system is influenced by its structural parameters, such as unit cell size (d), element height (h). 元件 ), component width (d) 元件 ), opening width (w) and incident angle (θ) inc ).

[0071] Figure 4 This is a schematic cross-sectional view of the power distribution in some implementations for the case of two dielectric edges irradiated by a plane wave.

[0072] The diffraction of an incident plane wave (TE or TM) from the edge of a dielectric microstructure separating two media results in local light confinement (optical hotspots) and local light deflection in the high-refractive-index medium, which can be termed a photonic nanojets (PNJ). This nanojets are a result of a combination of the incident electric field component and the longitudinal component formed due to the edge. Figure 4An example of a structure is shown that combines two photonic nanojet streams (PNJ_1 and PNJ_2) derived from the symmetrical opposite edges of a microstructure to form a single focused optical hot spot (PNJ_1+PNJ_2).

[0073] Reference Figure 4 The angle between the photonic nanojet (PNJ_1 or PNJ_2) and the vertical direction depends on the ratio of the two refractive indices around the edge, and can be approximated as follows:

[0074]

[0075] The intersection of two symmetrical, opposing photon nanojets generated by the edge of the rectangular block can be understood as a microlens, the focal length of which can be estimated using the following expression:

[0076]

[0077] This represents the full width of the structure forming the combined photonic nanojet. For normal incidence, the focal point will be located on the axis of symmetry of the microlens. The height h of the dielectric block... 元件 It can be selected as close to the critical height h c ,in

[0078]

[0079] Choose a height close to the critical height h c height h 元件 This can help increase the intensity of the generated photonic nanojet.

[0080] The total width of the dielectric block can be from f ≥ h 元件 The conditions are chosen to begin with f, where f is the distance from the base of the edge that produces these nanojets in the combined photonic nanojets. f can be called the focal length of the photonic nanojets microlens. This leads to the following expression:

[0081]

[0082] Some implementations include a conductive layer with openings that are used to form a substantially spherical wave due to diffraction, which, when appropriately sized, can constructively interfere with the edge diffracted wave at the output of the element for a fixed wavelength.

[0083] Figures 5A to 5B This is a schematic diagram of the combination of edge diffraction waves and spherical waves. Due to the constructive interference between the edge diffraction waves and spherical waves, this combination can lead to an increase in optical power at a fixed wavelength. Figures 5A to 5B The principle of electric field distribution that can be used in some implementation schemes is shown.

[0084] Figure 5AThe diagram shows a plane wave 502 incident on a dielectric element 504 covered by a conductive layer 506. The sides of the dielectric element 504 are not covered by the conductive layer. This configuration produces a diffracted edge wave 508 that converges toward the center of the dielectric element.

[0085] Figure 5B A plane wave 510 is shown incident on a dielectric element 512 covered by a top conductive layer 514, in which a top opening 516 is provided. The top opening causes a spherical wave 518 to propagate through the element. An opening 520 in the bottom conductive layer 522 causes an additional spherical wave 524 to propagate through the substrate region 526.

[0086] Exemplary implementations operate to generate edge waves (such as...) Figure 5A Wave 508) together with spherical waves (such as Figure 5B The waves (518) are combined in such a way that they constructively interfere with each other for the desired wavelength.

[0087] Considering wave reflection from the conductive layer and the side surfaces of the elements, waves diffracted by the side edges of the array of elements constructively interfere with spherical waves generated by the openings on the top of the elements. Some embodiments are for λ. inc =940nm to achieve this constructive interference to increase the amount of light reaching and being absorbed by the silicon photodetector below, thereby increasing its absorption capability at that wavelength.

[0088] Figures 6A to 6D Different configurations of an optical system are shown, with variations in the position of the conductive layer and the openings therein.

[0089] Figures 6A to 6D The functionality of using open conductive layers in different configurations for a fixed topology with the following physical dimensions: d = 2300 nm, d 元件 =1350nm, h 元件 =1750nm. The spectral characteristics for each case are presented in Figures 7A to 7B In the context of systems without a conductive layer ( ). Figure 6A We are Figure 7A Curve 702 shows a relatively uniform increase in optical power in silicon that varies with the incident wavelength, which may not be desirable for wavelength-selective systems. Next, considering the case of only one conductive layer with an opening, whether below the unit cell element ( Figure 6B ) or above ( Figure 6C We still haven't observed a substantial resonance dependence of optical power for a fixed incident wavelength, as shown by curve 704 (corresponding to...). Figure 6B (units) and curve 706 (corresponding to) Figure 6C As seen in the unit. For Figure 6DIn the same situation, a lack of substantial resonance was observed in curve 708. Figure 6D The design provides two conductive layers with openings, but the opening on the bottom layer extends across the entire unit cell element.

[0090] Figure 8 This is a schematic cross-sectional view of a unit cell with conductive layers located above and below the unit cell element and 200 nm openings. This example demonstrates an approximately 3.5-fold increase in optical power concentration for the peak wavelength compared to other wavelengths.

[0091] Figure 9 This shows the results determined through simulation. Figure 8 A graph showing the spectral variation of optical power in silicon in the proposed implementation scheme. (Example:) Figure 9 As seen in λ inc A strong peak exists in the near-infrared region at a wavelength around 940nm.

[0092] Figure 10 It is for λ inc =940nm, for unit cell width d=2300nm and slit width w=400nm, for h 元件 and d 元件 A schematic diagram showing the simulation results of optical power in silicon substrates with different values.

[0093] The effect of parameter variations on the optical response of the system was investigated by performing numerical simulations in COMSOL Multiphysics software. The simulation used TM polarized plane waves and measured the optical power within a 3 μm thick silicon substrate by calculating the Poynting vector (optical power). Figure 10 The diagram schematically illustrates the initial value d = 2300 nm for the unit cell width at 940 nm and for the element height h. 元件 and component width d 元件 The variation in peak power distribution is observed in the optical power distribution. Two regions of interest exhibit high optical power in silicon, namely regions I and II in the figure. Analyzing the coordinates of region I, we can note the variation in h. 元件 Approaching the critical height of the component. Region I typically covers a height h between approximately 1600 nm and 1900 nm. 元件 and a width d between approximately 1100nm and 1400nm 元件 Region II typically covers a height h between approximately 900 nm and 1300 nm. 元件 and a width d between approximately 750nm and 1050nm 元件 .

[0094] Figure 11 This shows the results determined through simulation. Figure 10The graph shows the spectral dependence of the optical power in silicon at normal incidence for the optimized system around region I. In the simulated element, the lateral dimension of the cell is 2300 nm, the element width is 1350 nm, the element height is 1750 nm, and the opening in the conductive layer has a width of 200 nm.

[0095] The simulation corresponds to the structure of region I and produces Figure 11 The spectral distribution is shown. Compared to the power at other wavelengths, the power at λ... inc Centered on 939.8nm, the optical power in silicon has increased.

[0096] Figure 12 It shows the corresponding Figure 10 The graph shows the spectral variation of optical power in silicon at different incident angles for different physical parameters of region I.

[0097] Figure 12 The simulation results are shown, illustrating the effect of incident angle variations on optical power in silicon at incident angles of 0°, 2°, and 4°. (See figure...) Figure 12 It can be seen that the optical power in silicon is strongly dependent on the incident angle. This effect can be described as the peak splitting into two smaller peaks when the incident angle deviates from normal incidence. This effect suggests that choosing the physical parameters in region I may result in an implementation that is less robust in practical applications.

[0098] Reference Figure 10 In region II, the component height h 元件 and component width d 元件 The value is almost half of the value in region I. Figure 13 The optical power in silicon is shown for a set of physical parameters around region II, which is configured to filter in a wavelength range centered at 939.8 nm. Figure 13 This shows a size of d = 2050 nm, d 元件 =690nm, h 元件 A graph showing the simulated spectral variation of optical power in silicon for implementations with unit cells of 1085 nm and 200 nm.

[0099] Figures 14A to 14C This shows the partial resonant wavelength ( Figure 14A 775nm and Figure 14C (1044.5nm) and center resonant wavelength ( Figure 14B The optical power redistribution at 939.8 nm shows the interaction between waves originating from the edge and spherical waves from openings in the top conductive layer. Figure 14AThe optical trajectory 1402 of the edge wave originating from the left edge of the element is shown (the edge wave originating from the right edge will follow a similar but symmetrically opposite trajectory, but for clarity they are not shown in the figure). These edge waves from the left and right surfaces of the element are reflected by the side surfaces and bounce back and forth, interfering with the spherical waves originating from the opening 1408 in the upper conductive layer (shown by trajectories 1404, 1406).

[0100] Figures 14A to 14C The outline drawn in the image shows the region where the edge wave and the spherical wave are in phase and exhibit constructive interference. (See image for details.) Figure 14B As seen, the system parameters can be selected such that these waves constructively interfere with each other at the opening 1414 in the bottom conductive layer at the desired wavelength (e.g., 940 nm) to generate high optical power in the silicon substrate 1412.

[0101] Figures 14A to 14C The effect of conductive layers on achieving resonance is shown, as they not only reflect unwanted waves to prevent them from entering the silicon photodetector, but also help enhance optical hotspots at openings in the bottom conductive layer due to the constructive interference of the generated nanojets with the spherical waves. Plasma surface waves can be generated at the boundaries of the conductive layers.

[0102] Variations in the incident angle of light, the width of the opening in the conductive layer, and the width of the unit cell can also lead to variations in the optical power in silicon.

[0103] Figure 15 This is a graph showing the simulated optical power in silicon for incident light at different angles. The peak position and peak intensity have good tolerance for incident angles from 0 to +5°. Because the simulated structure is symmetrical about the vertical axis, the system can also be understood to tolerate incident angles from 0 to -5°. As the incident angle increases, the width of the resonant peak decreases, which can be understood as the effect of the finite width of the opening in the bottom conductive layer. Oblique incidence at wavelengths of constructive interference at 0° incident angle is blocked, resulting in this reduction in peak width. Figure 16 This variation is shown as a curve of the full width at half maximum (FWHM) of the peak centered at 939.8 nm, varying with the incident angle. For normal incidence, the FWHM is maximum at approximately 128 nm, and for 5° incidence, the FWHM decreases to approximately 70 nm.

[0104] Simulations have been used to study the spectral variation of optical power in silicon for different values ​​of unit cell width d. When the unit cell width varies, the spectral position of the peak hardly changes. The aspect ratio of the unit cell element and the width of the opening in the conductive layer appear to have a much larger effect on the optical power.

[0105] Figure 17 This is a graph showing the spectral variation of optical power in silicon for different opening widths w in the conductive layer. Figure 17 In the study, changes in the peak wavelength and the full width at half maximum (FWHM) of the optical power peak are visible as the slit width changes. The center wavelength of the peak decreases relatively linearly from 963.9 nm for a slit width of 50 nm to 920 nm for a slit width of 300 nm.

[0106] Figure 18 This is a graph showing the effect of the width of the opening in the conductive layer on the spectral position of the center wavelength.

[0107] The peak FWHM increased from 21.7 nm for an aperture width of 50 nm to 114.5 nm for an aperture width of 200 nm. Table 1 summarizes these two results.

[0108] PEC slit width (nm) FWHM(nm) Spectral position of the center wavelength (nm) 50 21.7 963.9 100 42.8 954.7 150 73.6 948.7 200 114.5 939.8 250 - 928.1 300 - 919.3

[0109] Table 1: FWHM and center wavelength position for different aperture widths.

[0110] In some embodiments, the width of the slits or other openings in the top and bottom surfaces of the element is between 150 nm and 250 nm. In some embodiments, the width of the slits or other openings in the top and bottom surfaces of the element is between 50 nm and 300 nm.

[0111] Figure 19 This is a graph showing the effect of the width of the opening in the conductive layer on the FWHM of the corresponding peak.

[0112] Simulations have been performed to determine the silicon optical power for different values ​​of the conductive layer aperture width and different incident angles for 940 nm incident light. It has been found that for incident light with angles between -5° and 5°, a width of approximately 180 nm to approximately 230 nm can be used in some embodiments to obtain high silicon optical power. Other embodiments may use values ​​outside this range to achieve other properties.

[0113] Exemplary implementations provide unit cell element designs that can be used with silicon photodetectors. Some implementations utilize the constructive interference phenomenon between edge-diffracted waves and spherical waves to target wavelengths of selected wavelengths (such as λ). inc The optical power reaching the silicon layer is increased in the wavelength band centered at 939.8 nm. Some such implementations use a unit cell width d of 2050 nm. Some implementations include a width of 690 nm and a height substantially equal to 0.6 h. c The photopolymer material element, wherein h c It is the critical height, where

[0114]

[0115] In some embodiments, conductive layers are disposed at the top and bottom of the photopolymer element, and openings with a width of 200 nm are formed in the conductive layers. Such embodiments are well-suited for incident wave angles from -5° to +5°.

[0116] Different parameters can be selected in different implementation schemes to change the spectral behavior of the unit cell. Parameters such as: h 元件 d 元件 The width w of the openings in the conductive layer. In some implementations, the top and bottom openings have different widths. Changing these parameters modifies the spatial pattern of the constructive interference, and thus modifies the central resonant wavelength. It has been found that the unit cell width d has little effect on the spectral form of optical power in silicon, and the small variations observed in optical power can be attributed to crosstalk due to the periodic boundary conditions of the unit cell.

[0117] like Figures 20A to 20F As seen above, different implementation schemes can also have different configurations. Figures 20A to 20F In the diagram, the shaded areas represent the portions of the optical element covered by the conductive layer, while the unshaded areas represent openings in the conductive layer (referred to in the simulation as PEC slits). Openings in the upper and lower conductive layers can have the same size, shape, and orientation, or they can have different sizes, shapes, and / or orientations. Various combinations of circular, square, elliptical, rectangular, and other shapes can be used for both the optical element and the openings in the conductive layer.

[0118] In some implementations, the side of the optical element has one or more angles relative to the substrate other than 90°. As an example, Figure 21 This is a schematic cross-sectional view of a unit cell 2300 according to some embodiments. The unit cell 2300 includes an element 2302 with a rectangular cross-section. The element 2302 may be made of a commercially available polymeric photoresist (such as Microchem 495 PMMA). The element 2302 may be disposed on a silicon substrate 2304. The silicon substrate 2304 may include a CMOS sensor or other photodetector. Conductive layers 2306 and 2308, which may be metal layers, are disposed above and below the rectangular element 2302. The conductive layers 2306 and 2308 include corresponding openings 2310 and 2312. Figure 21 In the example, the side surfaces 2314, 2316 of element 2302 form an angle α with the substrate that is different from 90°. In some embodiments, α is between 80° and 100°. In some embodiments, α is between 70° and 90°.

[0119] In some implementations, the unit cells, as described herein, are arranged in a two-dimensional array. In some implementations, photodetectors (e.g., pixels of a CMOS sensor) are located below each unit cell within the unit cells.

[0120] While the examples above primarily relate to the use of devices configured for near-infrared light, other embodiments are configured for longer or shorter wavelengths, such as far-infrared, visible, or ultraviolet light, or for waves in other parts of the electromagnetic spectrum. Such embodiments may employ materials that are transparent to their designed wavelength.

[0121] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements.

Claims

1. An optical component, the optical component comprising: A dielectric structure having at least one side surface, a top surface, and a bottom surface, wherein the at least one side surface is open to receive incident electromagnetic radiation; The first conductive layer on the upper surface has a first opening positioned to receive incident electromagnetic radiation. and The second conductive layer on the lower surface has a second opening positioned to emit electromagnetic radiation. The dielectric structure is configured such that electromagnetic radiation of a selected wavelength, entering the dielectric structure through the first opening and through the side surface, causes constructive interference at the second opening.

2. The optical component according to claim 1, wherein the cross-section of the dielectric structure is substantially rectangular.

3. The optical component according to claim 1 or 2, wherein the first opening and the second opening have substantially the same width.

4. The optical component according to claim 1 or 2, wherein the first opening and the second opening are substantially centered on the dielectric structure.

5. The optical component according to claim 1 or 2, wherein the dielectric structure is mounted on a silicon substrate, and the second opening is positioned to emit electromagnetic radiation into the silicon substrate.

6. The optical component according to claim 1 or 2, further comprising: A photodetector located beneath the dielectric structure.

7. The optical component according to claim 1 or 2, wherein the dielectric structure has a height h between 1600 nm and 1900 nm. 元件 and the width d between 1100nm and 1400nm 元件 .

8. The optical component according to claim 1 or 2, wherein the dielectric structure has a height h between 900 nm and 1300 nm. 元件 and the width d between 750nm and 1050nm 元件 .

9. The optical component according to claim 1 or 2, wherein the first opening and the second opening each have a width between 150 nm and 200 nm.

10. The optical component according to claim 1 or 2, wherein the optical component is configured to selectively transmit wavelengths. Incident electromagnetic radiation, wherein the height h of the dielectric structure is... 元件 Basically equal to ,in It is the refractive index of the dielectric structure and It is the refractive index of the surrounding medium.

11. An image sensor comprising a two-dimensional array of optical components according to any one of claims 1-3.

12. A method for use in an optical component, the method comprising: Electromagnetic radiation is directed onto an optical component, wherein the optical component includes: A dielectric structure having at least one side surface, a top surface, and a bottom surface, wherein the at least one side surface is open to receive incident electromagnetic radiation; A first conductive layer on the upper surface, the first conductive layer having a first opening positioned to receive incident electromagnetic radiation; and The second conductive layer on the lower surface has a second opening positioned to emit electromagnetic radiation. The dielectric structure is configured such that electromagnetic radiation of a selected wavelength, entering the dielectric structure through the first opening and through the side surface, causes constructive interference at the second opening.

13. The method for use in an optical component according to claim 12, wherein the height h of the dielectric structure is... 元件 Basically equal to ,in It is the refractive index of the dielectric structure and It is the refractive index of the surrounding medium, and in which It is the wavelength of the incident electromagnetic radiation.

14. The method for use in an optical component according to claim 12 or 13, the method further comprising: Operate a photodetector to detect the amount of electromagnetic radiation emitted through the second opening.

15. The method for use in an optical component according to claim 12 or 13, wherein the cross-section of the dielectric structure is substantially rectangular.

16. The method for use with an optical component according to claim 12 or 13, wherein the first opening and the second opening have substantially the same width.

17. The method for use in an optical component according to claim 12 or 13, wherein the dielectric structure is mounted on a silicon substrate, and the second opening is positioned to emit electromagnetic radiation into the silicon substrate.

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