Optical interference filter

Abstract

In some embodiments, the optical interference filter includes: a substrate; and an assembly of layers disposed on the substrate, wherein the assembly of layers includes: a first subset of layers; and a second subset of layers; wherein: each layer in the first subset of layers comprises aluminum nitride (AlN) material, the stress of each layer in the first subset of layers is between -1000 and 800 MPa, the first subset of layers has a first refractive index having a first value, each layer in the second subset of layers comprises at least one other material, the second subset of layers has a second refractive index having a second value different from the first value, and the optical interference filter has an effective refractive index greater than or equal to 95% of the highest of the first and second values.

Description

Background Technology

[0001] Optical devices can be used to capture information about light. For example, an optical device can capture information about a set of wavelengths associated with light. An optical device may include a set of sensor elements (e.g., optical sensors, spectral sensors, and / or image sensors) for capturing information. For example, an array of sensor elements can be used to capture information associated with multiple wavelengths. The array of sensor elements can be associated with a filter. The filter may include a passband associated with a first wavelength range of light that passes through the array of sensor elements. The filter may also be associated with blocking light of a second wavelength range from passing through the array of sensor elements. Summary of the Invention

[0002] In some embodiments, the optical interference filter includes: a substrate; and an assembly of layers disposed on the substrate, wherein the assembly of layers includes: a first subset of layers; and a second subset of layers; wherein: each layer in the first subset of layers comprises aluminum nitride (AlN) material, the stress of each layer in the first subset of layers is between -1000 and 800 MPa, the first subset of layers has a first refractive index having a first value, each layer in the second subset of layers comprises at least one other material, the second subset of layers has a second refractive index having a second value different from the first value, and the optical interference filter has an effective refractive index greater than or equal to 95% of the highest of the first and second values.

[0003] In some embodiments, the optical interference filter includes: a set of layers, the set of layers including: a first subset of layers; and a second subset of layers, wherein: each layer in the first subset of layers includes an AlN material, the first subset of layers has a first refractive index having a first value, each layer in the second subset of layers includes helium-containing silicon hydride (Si:H-He), the second subset of layers has a second refractive index having a second value greater than the first value, and the optical interference filter has an effective refractive index greater than or equal to 95% of the second value.

[0004] In some embodiments, a method includes supplying an inert gas to a chamber, wherein the inert gas includes at least one of argon (Ar) or helium (He); supplying nitrogen (N2) to the chamber; and sputtering an aluminum (Al) target to form a first layer assembly comprising AlN on a substrate based on the supply of the inert gas and N2 gas, wherein: the first layer assembly and a second layer assembly are alternately formed on the substrate to form a layer configuration, the second layer assembly comprising Si:H-He, and the layer configuration having an effective refractive index greater than or equal to 3.7. Attached Figure Description

[0005] Figure 1 This is an overview diagram of the example implementation described in this article.

[0006] Figure 2 This is a diagram of the example filter described in this article.

[0007] Figure 3 This is an example illustration of a sputtering deposition system used to manufacture the filters described herein.

[0008] Figures 4A to 4B This is a diagram illustrating an example stress curve of an AlN layer formed using the sputtering process described herein.

[0009] Figure 5 This is a diagram illustrating example curves of the extinction coefficient and refractive index of an AlN layer assembly formed using the sputtering process described herein.

[0010] Figure 6 This is a graph illustrating example curves showing the transmittance performance of the filter described herein.

[0011] Figures 7A to 7C These are illustrations of the optical and physical properties of the exemplary embodiments described herein.

[0012] Figures 8A to 8C These are illustrations of the optical and physical properties of the exemplary embodiments described herein. Detailed Implementation

[0013] The following detailed description of exemplary embodiments is given with reference to the accompanying drawings. The same reference numerals in different drawings may identify the same or similar elements. The following description uses a spectrometer as an example. However, the techniques, principles, processes, and methods described herein can be used with any sensor, including but not limited to other optical and spectral sensors.

[0014] Filters can be fabricated by forming one or more layers on a substrate. For example, a conventional filter may include alternating layers of at least a first, second, and third material (e.g., alternating layers of silicon hydride (Si:H), silicon dioxide (SiO2), and tantalum pentoxide (Ta2O5)) to allow the conventional filter to pass a threshold percentage of light (e.g., at least 65%) associated with a specific spectral range (e.g., a spectral range between 800 and 1600 nanometers (nm)). However, forming alternating layers of at least three materials is complex and may result in the formation of low-quality layers that introduce defects or allow defects to propagate through the conventional filter. This can degrade the performance, manufacturability, and / or reliability of the conventional filter.

[0015] Furthermore, in many cases, the stress in each of one or more layers of a conventional filter is compressive (e.g., the stress in a layer is less than 0 MPa), resulting in the stress (e.g., net stress) of one or more layers being compressive. This causes the conventional filter to bend (e.g., flex). This results in one or more layers being affected by coating runoff, which impacts the performance of the conventional filter. It also makes the conventional filter more fragile (e.g., compared to a flat filter) and / or makes its transport, handling, and / or use difficult.

[0016] Additionally, the filtering performance of a conventional filter may degrade when the angle of incidence (AOI) of light directed to the filter changes from a configured angle of incidence (e.g., 0 degrees (normal), 30 degrees, 45 degrees, etc.) to a threshold angle of incidence (e.g., a deviation greater than about 10 degrees from the configured angle of incidence, a deviation greater than about 20 degrees from the configured angle of incidence, and / or a deviation greater than about 30 degrees from the configured angle of incidence). For example, a conventional filter may shift towards lower wavelengths as the angle of incidence increases. In this way, a conventional filter may allow unwanted or undesirable light to pass through, which may affect the sensing accuracy of optical sensors that receive the transmitted light.

[0017] Angular offset can be related to the effective refractive index of a filter (e.g., a bandpass filter). For example, a higher effective refractive index is associated with a lower angular offset. The effective refractive index can be calculated based on the component refractive indices of the filter's constituent materials. For example, for a filter having a mirror formed of alternating layers of high-refractive-index and low-refractive-index constituent materials, the effective refractive index can be calculated, at least in part, based on a set of equations of the following form:

[0018]

[0019]

[0020] Where n eff_H n is the upper limit of the effective refractive index of a filter that uses a high refractive index layer (e.g., greater than a threshold, such as greater than 2.0) as a spacer between mirrors. eff_L The effective refractive index of a filter that uses a low refractive index layer (e.g., less than or equal to a threshold, such as less than or equal to 2.0) as a spacer between mirrors is n. H It is the refractive index of the high refractive index layer material of each mirror and is used for n eff_H In the spacer, n L It is the refractive index of the low-refractive-index layer material of each mirror and is used for n eff_L In the spacers, m is the order of the spacers (e.g., the size of the spacers is a multiple of half the center wavelength of the filter). According to these equations, neff n H n L The relationship takes the following form:

[0021] n H >n eff >nL (3)

[0022] Another calculation of the effective refractive index may involve the observed wavelength shift (e.g., angular shift) of the filter. For example, the wavelength shift of a filter (e.g., a bandpass filter) at a particular incident angle can be determined based on an equation of the form:

[0023]

[0024] Where, λ θ Let λ0 represent the center wavelength at the incident angle θ, and λ0 represent the center wavelength at the incident angle (e.g., normal incident angle or another incident angle) where the filter is configured. The above equations can be rearranged to calculate the effective refractive index based on the observed wavelength shift:

[0025]

[0026] The equations above show that, for filters, a higher effective refractive index results in a lower angular offset. However, the limitation on the effective refractive index of a filter is less than the refractive index of the highest refractive index material in the filter (Equation 3).

[0027] Some embodiments described herein provide a filter comprising an assembly of layers disposed on a substrate. The assembly of layers may include a first subset and a second subset of layers arranged in an alternating layer sequence, the first subset comprising an aluminum nitride (AlN) material, and the second subset comprising at least one other material (e.g., at least one material not AlN), such as helium-containing silicon hydride (Si:H-He) material. In some embodiments, the filter allows a threshold percentage of light (e.g., at least 90%) associated with a specific spectral range (e.g., a spectral range between 800 nm and 1600 nm) to pass through. In this manner, the filter provides improved transmission performance compared to conventional filters. Furthermore, the filter comprises only two alternating layers, which reduces the complexity associated with forming the assembly of layers. This reduces the likelihood of forming low-quality layers and thus reduces the likelihood of introducing or allowing defects to propagate through the filter. Therefore, the performance, manufacturability, and / or reliability of the filter are improved compared to conventional filters.

[0028] In some embodiments, the stress of the first subset of layers comprising AlN material can be between -1000 and 800 MPa. Therefore, in some embodiments, when the stress of the second subset of layers is compressive, the stress of the AlN material can be configured to be tensile (e.g., greater than or equal to 0 MPa), and vice versa. In this way, the amount of bending caused by the layer assembly disposed on the substrate can be minimized (e.g., by balancing the stress of the compressive layers and the tensile layers of the filter). For example, one of the first subset and the second subset of layers may comprise a tensile material, while the other may comprise a compressive material, which can result in the stress of the layer assembly being approximately zero MPa (e.g., within tolerance). This minimizes the amount of bending in the filter, which reduces coating runoff and thereby improves the filter's performance (e.g., compared to conventional filters subjected to bending). This also improves the filter's durability and / or makes the transport, handling, and / or use of the filter easier compared to conventional filters subjected to bending. In certain examples, such as when the diameter of the filter is approximately 200 millimeters (mm), some embodiments described herein enable the filter's bending amount to be particularly less than 10 mm, less than 5 mm, and / or less than 0.1 mm. In another example, when the filter is configured to allow light associated with wavelength λ to pass through, in other examples, some embodiments described herein enable the filter's bending amount to be particularly less than λ / 4, less than λ / 10, and / or less than λ / 100.

[0029] Furthermore, some embodiments described herein provide a low-angle offset filter wherein the effective refractive index is greater than 95% of the refractive index of the highest refractive index material in the low-angle offset filter. For example, the low-angle offset filter may have an effective refractive index in the following form:

[0030]

[0031] Additionally or alternatively, the low-angle offset filter may have an effective refractive index greater than 100%, 110%, 120%, etc., of the refractive index of the highest refractive index material in the low-angle offset filter. In this way, the low-angle offset filter reduces the amount of unwanted or undesirable light passing through it, which improves the sensing accuracy of the optical sensor receiving the light passing through the low-angle offset filter.

[0032] Figure 1 This is an overview diagram of an example implementation 100 described herein. For example... Figure 1As shown, example embodiment 100 includes a sensor system 110. Sensor system 110 may be part of an optical system and may provide an electrical output corresponding to a sensor-defined value. Sensor system 110 includes a filter structure 120 and an optical sensor 140, the filter structure 120 including a filter 130. For example, filter structure 120 may include filter 130 performing a passband filtering function. In another example, filter 130 may be aligned with an array of sensor elements of optical sensor 140.

[0033] While some of the implementations described herein can be based on filters in a sensor system, the implementations described herein can be used in another type of system, outside of a sensor system, or in other configurations.

[0034] like Figure 1 As further shown, and indicated by reference numeral 150, the input optical signal is directed to filter structure 120 at one or more incident angles θ. For example, input optical signals 150-1 and 150-2 may be directed to filter 120 at incident angles θ0 (e.g., the configured incident angle) and θ. The input optical signal may include, but is not limited to, light associated with a specific spectral range (e.g., a spectral range centered at approximately 900 nm, such as a spectral range of 800 nm to 1000 nm; a spectral range of 800 nm to 1600 nm; a spectral range between 800 nm and 1100 nm; a spectral range between 1400 nm and 1600 nm, such as a spectral range with a peak wavelength of 1550 nm; a spectral range of 500 nm to 5500 nm; or another spectral range). For example, a light emitter may direct light to optical sensor 140 to allow optical sensor 140 to perform light measurements. In another example, the light emitter can direct light from another spectral range for another function (especially such as testing, sensing, or communication functions).

[0035] like Figure 1As further shown, and indicated by reference numeral 160, a first portion of the optical signal having a first spectral range is not passed through filter 130 and filter structure 120. For example, a dielectric filter stack that may include a high-refractive-index material layer and a low-refractive-index material layer of dielectric film layer of filter 130 may cause the first portion of light to be reflected or absorbed in a first direction. In this case, the first portion of light may be a threshold portion of light incident on filter 130 that is not included in the bandpass of filter 130, such as more than 95% of the light not being in a specific spectral range centered at approximately 900 nm. As shown by reference numeral 170, a second portion of the optical signal is passed through filter 130 and filter structure 120. For example, filter 130 may allow light having a second spectral range to pass through in a second direction toward optical sensor 140. In this case, the second portion of light may be a threshold portion of light incident on filter 130 within the bandpass of filter 130, such as more than 50% of the incident light in a spectral range centered at approximately 900 nm. The second portion of the light can be deflected through filter 130 at an angle less than a threshold, as described in more detail herein.

[0036] like Figure 1 As further shown, based on the second portion of the optical signal transmitted to the optical sensor 140, the optical sensor 140 can provide an output electrical signal 180 for the sensor system 110, particularly for purposes such as imaging, ambient light sensing, detecting the presence of an object, performing measurements, or facilitating communication. In some embodiments, another arrangement of the filter 130 and the optical sensor 140 can be utilized. For example, instead of allowing the second portion of the optical signal to pass collinearly with the input optical signal, the filter 130 can direct the second portion of the optical signal in a different direction to the optical sensor 140 at a different location.

[0037] As mentioned above, Figure 1 This is provided as an example. Other examples may be provided related to... Figure 1 The descriptions are different.

[0038] Figure 2 This is a diagram of an example filter 200. In some embodiments, the filter 200 may be an optical interference filter and / or may particularly include at least one of the following: a spectral filter, a multispectral filter, a bandpass filter, a blocking filter, a long-pass filter, a short-pass filter, a dichroic filter, a linearly variable filter, a circularly variable filter, a Fabry-Perot filter, a Bayer filter, a plasma filter, a photonic crystal filter, a nanostructure or metamaterial filter, an absorption filter, a beam splitter, a polarization beam splitter, a notch filter, an anti-reflective filter, a reflector, or a mirror. Figure 2An example stack of filter 200 is shown. Figure 2 As further shown, the filter 200 includes a substrate 210 and a layer assembly 220.

[0039] The substrate 210 may, in particular, comprise a glass substrate, a polymer substrate, a polycarbonate substrate, a metal substrate, a silicon (Si) substrate, a germanium (Ge) substrate, or an active device wafer (e.g., including a photodiode (PD), a PD array, an avalanche photodiode (APD), an APD array, a charge-coupled device (CCD) sensor, and / or a complementary metal-oxide-semiconductor (CMOS) sensor). In some embodiments, the thickness of the substrate 210 may be greater than or equal to 20 micrometers (μm), 50 μm, and / or 500 μm. Additionally or alternatively, the thickness of the substrate may be less than or equal to a specific thickness threshold. For example, the specific thickness threshold may be less than or equal to 5 millimeters (mm).

[0040] Layer set 220 (e.g., filter layer set) may be disposed (e.g., directly) on substrate 210 and may include one or more subsets of layers. For example, layer set 220 may include a first subset 230 of layers (e.g., first subsets 230-1 to 230-(N+1) (N≥1)) (also referred to herein as layer A) and a second subset 240 of layers (e.g., second subsets 240-1 to 240-N) (also referred to herein as layer B). In some embodiments, the first subset 230 and the second subset 240 of layers may be arranged in a specific order (e.g., alternating layer order), such as (AB). m (m≥1) sequence, (AB) m -A sequence, (BA) m Sequence, B-(BA) m One order or another. For example, such as Figure 2 As shown, the first subset 230 of the layer and the second subset 240 of the layer are (AB). N -A sequential positioning, wherein layer A (e.g., layer 230-1) is disposed on the surface (e.g., top surface) of filter 200, and layer A (e.g., layer 230-(N+1)) is disposed on the surface (e.g., top surface) of substrate 210.

[0041] In some embodiments, the layer assembly 220 may be disposed on a single surface (e.g., the top surface) of the substrate 210 (e.g., as shown in the image). Figure 2(As shown). Alternatively, a first portion of layer set 220 may be disposed on a first surface (e.g., top surface) of substrate 210, and a second portion of layer set 220 may be disposed on a second surface (e.g., bottom surface) of substrate 210. For example, a first portion of first subset 230 of layers and a first portion of second subset 240 of layers may be arranged on the first surface of substrate 210 in a first specific order, and a second portion of first subset 230 of layers and a second portion of second subset 240 of layers may be arranged on the second surface of substrate 210 in a second specific order.

[0042] In some embodiments, one or more additional layers may be included in the filter 200, such as one or more protective layers, one or more overlay layers (e.g., to provide environmental protection to the layer assembly 220), and / or one or more layers to provide one or more other filtering functions (particularly, for example, a barrier or anti-reflective coating). For example, in a single-surface configuration, additional layers (e.g., overlay layers), such as dielectric layers (e.g., including oxide materials such as silicon dioxide (SiO2), zirconium dioxide (ZrO2), and / or yttrium oxide (Y2O3); nitride materials such as silicon nitride (Si3N4), titanium nitride (TiN), and / or zirconium nitride (ZrN); and / or another material providing environmental protection) may be disposed on a surface (e.g., the top surface) of the layer assembly 220. As another example, in a dual-surface configuration, a first additional layer may be disposed on a surface (e.g., the top surface) of a first portion of the layer assembly 220, and a second additional layer may be disposed on a surface (e.g., the bottom surface) of a second portion of the layer assembly 220.

[0043] The first subset 230 of the layers may include aluminum nitride (AlN) material. For example, each layer 230 of the first subset 230 of the layers may include AlN material. The second subset 240 of the layers may include at least one other material (e.g., at least one material other than AlN material), particularly such as at least one of the following materials: silicon (Si) material, silicon and hydrogen (SiH) material, silicon hydride (Si:H) material, helium-containing silicon hydride (Si:H-He) material, amorphous silicon (a-Si) material, silicon nitride (SiN) material, germanium (Ge) material, germanium hydride (Ge:H) material, silicon germanium (SiGe) material, silicon germanium hydride (SiGe:H) material, silicon carbide (SiC) material, silicon carbide hydride (SiC:H) material, silicon dioxide (SiO2) material, tantalum pentoxide (Ta2O5) material, niobium pentoxide (Nb2O5) material, niobium titanium oxide (NbTiO) material. x Materials, niobium tantalum oxide (Nb) 2-x Ta xMaterials may include O5, titanium dioxide (TiO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), yttrium oxide (Y2O3), or hafnium oxide (HfO2). For example, each layer 240 of the second subset 240 of the layers may include at least one other material.

[0044] In some embodiments, the stress (e.g., net stress) of the first subset 230 of layers can be between -1000 MPa and 800 MPa (e.g., greater than or equal to -1000 MPa and less than or equal to 800 MPa). Additionally or alternatively, the stress of each layer 230 of the first subset 230 of layers can be between -1000 and 800 MPa. That is, the stress of a particular layer 230 in the first subset 230 of layers can be between -1000 and 800 MPa, and the stress of another particular layer 230 in the first subset 230 of layers can be between -1000 and 800 MPa. The stress of a particular layer 230 can be the same as or different from the stress of other particular layers 230. For example, the stress of a particular layer 230 can be tensile (e.g., greater than or equal to 0 MPa), while the stress of another particular layer 230 can be compressive (e.g., less than 0 MPa), or vice versa.

[0045] In some embodiments, the stress (e.g., net stress) of the layer set 220 may be approximately zero (0) MPa (e.g., within a tolerance where the tolerance is less than or equal to 5 MPa). Therefore, at least one of the first subset 230 and the second subset 240 of the layers may include a tensile material, while the other of the first subset 230 and the second subset 240 of the layers may include a compressive material (e.g., to make the stress of the layer set 220 approximately zero MPa). For example, the first subset 230 of the layers may include a tensile material, while the second subset 240 of the layers may include a compressive material, or vice versa. As another example, the first subset 230 of the layers may include a tensile AlN material, while the second subset 240 of the layers may include at least one other compressed material (particularly, for example, at least one of compressed Si material, compressed Si:H material, compressed Si:H-He material, or compressed a-Si material). In some embodiments, the stress (e.g., net stress) of the layer set 220 may be approximately equal to a specific amount of stress (e.g., within a tolerance where the tolerance is less than or equal to 5 MPa). For example, the first subset 230 and the second subset 240 of the layers may include a specific configuration of compressive and / or tensile materials such that the stress in the layer set 230 is equal to a specific amount of stress (such as 350 MPa).

[0046] In some embodiments, each layer in the layer set 220 may be associated with a specific thickness. For example, layers in the first subset 230 or the second subset 240 of layers may have a thickness between 5 nm and 2000 nm. In some embodiments, the first subset 230 or the second subset 240 of layers may be associated with multiple thicknesses, such as a first thickness of the first subset 230 and a second thickness of the second subset 240 of layers, a first thickness of a first portion of the first subset 230 and a second thickness of a second portion of the first subset 230 of layers, or a first thickness of a first portion of the second subset 240 of layers and a second thickness of a second portion of the second subset 240 of layers. Thus, the thickness of the layers and / or the number of layers may be selected based on a set of desired optical characteristics of the filter 200, such as a desired passband, a desired transmittance, and / or another optical characteristic. For example, the thickness and / or number of layers can be selected to allow the filter 200 to be used for (e.g., to allow light associated with the following spectral ranges to pass through) a spectral range between 800 nm and 1000 nm (e.g., having a center wavelength of approximately 900 nm), a spectral range between 800 nm and 1600 nm, a spectral range between 800 nm and 1100 nm, a spectral range between 1400 nm and 1600 nm (e.g., having a peak wavelength of 1550 nm), a spectral range between 500 nm and 5500 nm, or another spectral range.

[0047] In some implementations, layer set 230 may be configured to transmit light at a threshold percentage associated with a specific spectral range. For example, layer set 230 may be configured to transmit light at a threshold percentage associated with a spectral range between 800 nm and 1000 nm (e.g., with a center wavelength of approximately 900 nm). The threshold range may, for example, be greater than or equal to 85%. In some implementations, the extinction coefficient of the first subset 230 of layers may be less than 0.001 for light having wavelengths between 500 nm and 5500 nm.

[0048] In some embodiments, a first subset 230 of the layers may have a first refractive index having a first value, and a second subset 240 of the layers may have a second refractive index having a second value (e.g., different from the first value). For example, for light with wavelengths between 500 nm and 5500 nm, the refractive index of the first subset 230 of the layers may be between 1.9 and 2.2, and / or for light with wavelengths between 500 nm and 5500 nm, the refractive index of the second subset 240 of the layers may be between 3.5 and 3.9. In some embodiments, the filter 200 may have an effective refractive index greater than or equal to 95% of the higher of the first and second values. For example, when the first subset 230 of the layers and the second subset 240 of the layers are arranged in a specific layer sequence (e.g., an alternating sequence of high-refractive-index layers and low-refractive-index layers), the dimensions of the first subset 230 of the layers and the second subset 240 of the layers may be set to achieve, for example, an effective refractive index greater than or equal to 95% of the higher of the first and second values. In some embodiments, filter 200 may have an effective refractive index greater than or equal to 100% of the highest of the first and second values ​​(e.g., up to 110%, 120%, 130%, 140%, or 150% of the highest value). Therefore, for example, when the refractive index of the second subset 240 of the layer is between 3.5 and 3.9 and is greater than the refractive index of the first subset 230 of the layer, the effective refractive index may be greater than or equal to 3.7, 4.0, 4.5, 5.0, and / or 5.5.

[0049] In some embodiments, a sputtering process can be used to form the layer assembly 230. For example, a magnetron sputtering process (e.g., pulsed magnetron sputtering) can be used to sputter a first subset 230 of layers and / or a second subset 240 of layers (e.g., in an alternating layer sequence) onto the substrate 210 to form the layer assembly 230. In this way, the filter 200 can be manufactured. Further details regarding the manufacture of the filter 200 are provided herein. Figure 3 describe.

[0050] As mentioned above, Figure 2 This is provided as an example. Other examples may be provided related to... Figure 2 The descriptions are different.

[0051] Figure 3 This is a diagram of an example 300 of a sputtering deposition system used to manufacture the filters described herein (e.g., filter 200). The sputtering deposition system can be used to implement sputtering processes (such as magnetron sputtering).

[0052] like Figure 3 As shown, Example 300 includes a vacuum chamber 310 and a substrate 320 (e.g., corresponding to the description herein). Figure 2The described components include a substrate 210, a cathode 330, a target 331, a cathode power supply 340, an anode 350, a plasma activation source (PAS) 360, and a PAS power supply 370. The target 331 may comprise an aluminum (Al) material. The PAS power supply 370 may be used to power the PAS 360 and may include a radio frequency (RF) power supply. The cathode power supply 340 may be used to power the cathode 330 and may include a pulsed direct current (DC) power supply.

[0053] about Figure 3 The target 331 can be sputtered in the presence of nitrogen (N2) and / or an inert gas (e.g., including argon (Ar), helium (He), and / or neon (Ne)) to deposit aluminum nitride (AlN) as at least one layer on the substrate 320. For example, N2 gas and an inert gas can each be supplied to the vacuum chamber 310, which can cause sputtering of the target 331 to form a first layer assembly including AlN on the substrate 320 (e.g., as further described herein). In some embodiments, the first layer assembly can be alternately formed on the substrate with a second layer assembly including at least one other material to form a layer configuration, such as including Si, Si:H, Si:H-He, a-Si, and / or as described herein (e.g., with respect to this text relative to...). Figure 2 The second set of layers (240) refers to any other material in the second set of layers. A second set of layers can be formed on a substrate (e.g., in a manner similar to that further described herein) by supplying a second gas (e.g., hydrogen (H2)) and an inert gas (e.g., including Ar, He, and / or Ne) to a vacuum chamber 310 to induce sputtering of another target (e.g., a silicon target) to form a second set of layers (e.g., including Si:H or Si:H-He in this example).

[0054] In some embodiments, the layers may be arranged in a specific layer sequence (e.g., an alternating sequence of high-refractive-index layers and low-refractive-index layers) such that the effective refractive index of the layer configuration is greater than or equal to 95% of the value of the highest refractive-index material (e.g., up to 110%, 120%, 130%, 140%, or 150%). Thus, for example, the effective refractive index may be greater than or equal to 3.7, 4.0, 4.5, 5.0, and / or 5.5 (e.g., when the refractive index of a second subset of the layers is between 3.5 and 3.9 and is greater than the refractive index of a first subset of the layers).

[0055] To form the AlN layer, an inert gas can be supplied to the vacuum chamber 310 via the anode 350 and / or PAS 360. N2 gas can be introduced into the vacuum chamber 310 via PAS 360, which is used to activate the N2 gas. Additionally or alternatively, the cathode 330 can induce N2 gas activation (e.g., in this case, N2 gas can be introduced from another part of the vacuum chamber 310) or the anode 350 can induce N2 gas activation (e.g., in this case, N2 gas can be introduced into the vacuum chamber 310 via the anode 350). PAS 360 can be located near the threshold of the cathode 330, allowing plasma from PAS 360 and plasma from the cathode 330 to overlap. The use of PAS 360 allows AlN to be deposited at a relatively high deposition rate. In some implementations, AlN can be deposited at a deposition rate of about 0.05 nm / s to about 2.0 nm / s, at a deposition rate of about 0.5 nm / s to about 1.2 nm / s, at a deposition rate of about 0.8 nm / s, or similar rates.

[0056] In some embodiments, the stress of the AlN layer (e.g., after formation) can be adjusted based on controlling the composition of the inert gas and / or the amount of inert gas supplied to the vacuum chamber 310. For example, when the inert gas includes Ar, the amount of Ar in the inert gas and / or the amount of inert gas supplied to the vacuum chamber 310 can be controlled to keep the stress of the AlN layer between -230 MPa and 800 MPa. Additionally or alternatively, when the inert gas includes Ar, the amount of Ar in the inert gas and / or the amount of inert gas supplied to the vacuum chamber 310 can be controlled to keep the stress (e.g., net stress) of the first layer assembly including AlN between -230 MPa and 800 MPa. As another example, when the inert gas includes He and / or Ne, the amount of He and / or Ne in the inert gas and / or the amount of inert gas supplied to the vacuum chamber 310 can be controlled to keep the stress of the AlN layer between -1000 and 150 MPa. Additionally or alternatively, when the inert gas includes He and / or Ne, the amount of He and / or Ne in the inert gas and / or the amount of inert gas supplied to the vacuum chamber 310 can be controlled to make the stress of the first layer assembly including AlN between -1000 MPa and 150 MPa.

[0057] Although this document describes the sputtering process with specific geometries and implementations, other geometries and implementations are possible. For example, N2 gas can be injected, in particular, from another direction and / or from a gas manifold near the threshold of cathode 330. While this document describes different component configurations, different materials, different manufacturing processes, etc., can also be used to achieve different relative concentrations of AlN.

[0058] As mentioned above, Figure 3 Provided as an example. Other examples may be provided with reference to [the example]. Figure 3 The descriptions are different.

[0059] Figures 4A to 4B This is a diagram illustrating an example curve 400 of the stress in an AlN layer formed using the sputtering process described herein (e.g., magnetron sputtering). Figure 4A As shown, when the flow rate is between 120 and 370 standard cubic centimeters per minute (sccm) (e.g., to the flow rate described in this article regarding...) Figure 3 When the vacuum chamber 310 of the described sputtering deposition system is supplied with an inert gas including Ar, the stress of the AlN layer can be configured between -230 MPa and 650 MPa. Figure 4B As shown, when the flow rate is between 0 sccm and 500 sccm (e.g., to the flow rate described in this article regarding...) Figure 3 When the vacuum chamber 310 of the described sputtering deposition system is supplied with an inert gas comprising He, the stress in the AlN layer can be configured between -950 MPa and 175 MPa. In some embodiments, a flow rate between 120 sccm and 370 sccm (e.g., to the flow rate described herein) is also used. Figure 3 The vacuum chamber 310 of the described sputtering deposition system is supplied with an inert gas including Ar.

[0060] As mentioned above, Figures 4A to 4B Provided as an example. Other examples may be provided with reference to [the example]. Figures 4A to 4B The descriptions are different.

[0061] Figure 5 This is a plot of example curves 500 showing the extinction coefficient (k) and refractive index (r) of an AlN layer assembly formed using the sputtering process described herein (e.g., magnetron sputtering). Figure 5 As shown, for light with wavelengths between 500 nm and 2000 nm, the extinction coefficient can be less than 0.001. Figure 5 Furthermore, for light with wavelengths between 500 and 2000 nm, the refractive index can be less than 2.2.

[0062] As mentioned above, Figure 5 Provided as an example. Other examples may be provided with reference to [the example]. Figure 5 The descriptions are different.

[0063] Figure 6This is a diagram illustrating example curve 600 of the transmittance performance of the filter described herein (e.g., filter 200). The filter includes an assembly of layers (e.g., layer assembly 220), which includes a first subset of layers (e.g., first subset of layers 230) and a second subset of layers (e.g., second subset of layers 240), the first subset including AlN material and the second subset including Si:H material. Figure 6 As shown, the filter can transmit more than about 85% (approximately 92% peak) of light with wavelengths between 920 nm and 960 nm. In contrast, an alternative filter comprises an assembly of layers, including a first subset of layers comprising a Ta₂O₅ material and a second subset of layers comprising a Si:H material. The alternative filter can transmit more than about 60% (approximately 67% peak) of light with wavelengths between 920 nm and 960 nm. Therefore, for the spectral range between 920 nm and 960 nm, the filter described herein exhibits improved transmission performance compared to the alternative filter.

[0064] As mentioned above, Figure 6 Provided as an example. Other examples may be provided with reference to [the example]. Figure 6 The descriptions are different.

[0065] Figures 7A to 7C Figures 700 / 710 / 720 illustrate the optical and physical properties of the exemplary embodiments described herein.

[0066] like Figure 7A As shown, Figure 700 illustrates the angular offset performance of a filter (e.g., filter 200 described herein). For incident angles between 0 degrees and 30 degrees (e.g.... Figure 7A As shown by θ in the diagram, the angular offset at the center wavelength of the optical interference filter can be less than 1.0% of the center wavelength. For example, when the filter is configured for a center wavelength of 940 nanometers (nm), the filter can have an angular offset of, for example, less than 9.4 nm at incident angles up to 30 degrees. In some embodiments, the filter can have an angular offset of less than 7.0 nm at incident angles up to 30 degrees. In this case, the filter can achieve an effective refractive index, for example, greater than or equal to 3.7, 4.0, 4.5, 5.0, and / or 5.5. In some embodiments, the filter can achieve a transmittance greater than a transmittance threshold at the center wavelength, such as greater than (e.g., the peak transmittance of the filter at incident angles between 0 and 30 degrees) 80%, 85%, 90%, and / or 95%. Furthermore, the filter can achieve ripple of less than + / - 10%, less than + / - 5%, or less than + / - 1%, where ripple represents the deviation of the transmittance across the passband at an incident angle between 0 and 30 degrees.

[0067] like Figure 7B and Figure 7C As shown in Figures 710 and 720, an example stack and layer thickness of the filter are illustrated. In this case, the filter is fabricated by alternating layers comprising AlN material (e.g., having a refractive index between 1.9 and 2.2 for light with wavelengths between 500 nm and 5500 nm) and layers comprising Si:H-He material (e.g., having a refractive index between 3.5 and 3.9 for light with wavelengths between 500 nm and 5500 nm). The filter comprises one or two “thick layers” greater than a threshold thickness (e.g., a thickness greater than 200% of the next thickest layer after that one or more layers, but less than, for example, 500% of, the next thickest layer). In some embodiments, the filter may comprise two thick layers, and the deviation between the thick layers may be between 10% and 25%. For example, the thickness of the smaller of the two thick layers may be between 10% and 25% smaller than the thickness of the larger of the two thick layers.

[0068] As mentioned above, Figures 7A to 7C This is provided as an example only. Other examples may be found in relation to [the example provided]. Figures 7A to 7C The descriptions are different.

[0069] Figures 8A to 8C Figures 800 / 810 / 820 illustrate the optical and physical properties of the exemplary embodiments described herein.

[0070] like Figure 8A As shown, Figure 800 illustrates the angular offset performance of a filter (e.g., filter 200 described herein). For incident angles between 0 degrees and 30 degrees (e.g.... Figure 8A As shown by θ in the diagram, the angular offset at the center wavelength of the optical interference filter can be less than 1.0% of the center wavelength. For example, when the filter is configured for a center wavelength of 940 nanometers (nm), the filter can have an angular offset of, for example, less than 9.4 nm at incident angles up to 30 degrees. In some embodiments, the filter can have an angular offset of less than 7.0 nm at incident angles up to 30 degrees. In this case, the filter can achieve an effective refractive index, for example, greater than or equal to 3.7, 4.0, 4.5, 5.0, and / or 5.5. In some embodiments, the filter can achieve a transmittance greater than a transmittance threshold at the center wavelength, for example, greater than (e.g., the peak transmittance of the filter at incident angles between 0 and 30 degrees) 80%, 85%, 90%, and / or greater than 95%. In addition, the filter can achieve ripple of less than + / - 10%, less than + / - 5%, or less than + / - 1%, where ripple represents the deviation of the transmittance across the passband at an incident angle between 0 degrees and 30 degrees.

[0071] like Figure 8B and Figure 8CAs shown in Figures 810 and 820, an example stack and layer thickness of the filter are illustrated. In this case, the filter is fabricated by alternating layers comprising AlN material (e.g., having a refractive index between 1.9 and 2.2 for light with wavelengths between 500 nm and 5500 nm) and layers comprising Si:H-He material (e.g., having a refractive index between 3.5 and 3.9 for light with wavelengths between 500 nm and 5500 nm). The filter may also include an additional layer (e.g., a capping layer as described herein) comprising SiO2 material.

[0072] As mentioned above, Figures 8A to 8C This is provided as an example only. Other examples may be found with reference to [the example provided]. Figures 8A to 8C The descriptions are different.

[0073] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations can be made based on the foregoing disclosure, or modifications and variations can be obtained from the implementation of the embodiments.

[0074] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. It will be apparent that the systems and / or methods described herein can be implemented in various forms of hardware, firmware, and / or combinations of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not a limitation on the implementation. Therefore, this document describes the operation and behavior of the systems and / or methods without reference to any specific software code. It should be understood that software and hardware can be used to implement systems and / or methods based on those described herein.

[0075] As used in this article, depending on the context, a threshold can refer to a value that is greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, etc.

[0076] Even if a particular combination of features is recited in the claims and / or disclosed in the specification, such combinations are not intended to limit the disclosure of various embodiments. In fact, many of these features can be combined in ways not specifically recited in the claims and / or disclosed in the specification. While each dependent claim listed below may directly depend on only one claim, the disclosure of various embodiments includes each dependent claim in combination with each other claim in the claims list. As used herein, the phrase “at least one of the following” in the list of references refers to any combination of these items, including a single member. As an example, “at least one of the following: a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination having multiple identical items.

[0077] The elements, actions, or instructions used herein should not be construed as critical or necessary unless explicitly stated otherwise. Furthermore, as used herein, the articles “a” and “one” are intended to include one or more items and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items associated with the article “the” and may be used interchangeably with “the one or more.” Additionally, as used herein, the term “set” is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and may be used interchangeably with “one or more.” Where only one item is referred to, the phrase “only one” or similar language is used. Furthermore, as used herein, the terms “have,” “possess,” “own,” etc., are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “at least partially based on,” unless otherwise explicitly stated. Moreover, as used herein, the term “or,” when used in series, is intended to be inclusive and may be used interchangeably with “and / or,” unless otherwise explicitly stated (e.g., in combination with “either” or “only one”).

Claims

1. An optical interference filter, comprising: substrate; as well as A layer assembly is disposed on the substrate, wherein the layer assembly includes: The first subset of the layer; and The second subset of the layer, where: Each layer in the first subset of the layers comprises aluminum nitride (AlN) material. The stress in each layer of the first subset of the layers is between -1000 MPa and 800 MPa. A first subset of the layer has a first refractive index, and the first refractive index has a first value. Each layer in the second subset of the layers includes at least one other material, including helium-containing silicon hydride (Si:H-He) material, wherein the second subset of the layers has a second refractive index, the second refractive index having a second value different from the first value, and The optical interference filter has an effective refractive index that is greater than or equal to 95% of the highest of the first and second values; The net stress of the layer assembly is approximately zero MPa.

2. The optical interference filter according to claim 1, wherein for incident angles between 0 degrees and 30 degrees, the angular offset at the center wavelength of the optical interference filter is less than 1.0% of the center wavelength.

3. The optical interference filter according to claim 1, wherein a first subset of the layers and a second subset of the layers are disposed on the substrate in an alternating layer sequence.

4. The optical interference filter according to claim 1, wherein the at least one other material further comprises at least one of the following: Silicon (Si) materials; Silicon hydride (Si:H) material; Silicon and hydrogen (SiH) materials; Amorphous silicon (a-Si) materials; Silicon nitride (SiN) materials; Germanium (Ge) materials; Germanium hydride (Ge:H) material; Silicon-germanium (SiGe) materials; Hydrogenated silicon-germanium (SiGe:H) material; Silicon carbide (SiC) materials; Hydrogenated silicon carbide (SiC:H) material; Silica (SiO2) material; Tantalum pentoxide (Ta2O5) material; Niobium pentoxide (Nb₂O₅) material; Niobium titanium oxide (NbTiO) x )Material; Niobium tantalum pentoxide (Nb) 2-x Ta x O5) materials; Titanium dioxide (TiO2) material; Alumina (Al2O3) material; Zirconia (ZrO2) materials; Yttrium oxide (Y2O3) materials; or Hafnium oxide (HfO2) material.

5. The optical interference filter of claim 1, wherein an additional layer is disposed on the layer assembly; The additional layer comprises silicon dioxide (SiO2) material.

6. The optical interference filter of claim 1, wherein the optical interference filter is configured to allow light associated with a spectral range between 800 nm and 1600 nm to pass through.

7. An optical interference filter, comprising: The layer set includes: The first subset of the layer; and The second subset of the layer, where: Each layer in the first subset of the layers comprises aluminum nitride (AlN) material. A first subset of the layer has a first refractive index, and the first refractive index has a first value. Each layer in the second subset of the layers comprises a helium-containing silicon hydride (Si:H-He) material. The second subset of the layer has a second refractive index, which has a second value greater than the first value, and The optical interference filter has an effective refractive index greater than or equal to 95% of the second value; The net stress of the layer assembly is approximately zero MPa.

8. The optical interference filter of claim 7, wherein one of the first subset and the second subset of the layers comprises a stretching material, and The first subset of the layers and the other of the second subset of the layers comprise a compressible material.

9. The optical interference filter according to claim 7, wherein: For light with wavelengths between 500 nm and 5500 nm, the first value is between 1.9 and 2.2; and For light with wavelengths between 500 nm and 5500 nm, the second value is between 3.5 and 3.

9.

10. The optical interference filter of claim 7, wherein an additional layer is disposed on the layer assembly. The additional layer comprises silicon dioxide (SiO2) material.

11. The optical interference filter of claim 7, wherein for an incident angle between 0 degrees and 30 degrees, the optical interference filter has an angular offset of less than 7.0 nanometers (nm) at a wavelength of 940 nm, and the effective refractive index is greater than or equal to 3.

7.

12. The optical interference filter of claim 7, wherein for incident angles between 0 degrees and 30 degrees, the angular offset at the center wavelength of the optical interference filter is less than 1.0% of the center wavelength.

13. The optical interference filter according to claim 12, wherein the center wavelength is 940 nanometers.

14. The optical interference filter of claim 7, wherein for incident angles between 0 degrees and 30 degrees, the optical interference filter is associated with a transmittance between 90% and 100% of the peak transmittance of the optical interference filter.

15. An optical interference filter, comprising: substrate; as well as The configuration of the layer set on the substrate, the layer set including a first subset of layers and a second subset of layers, the first subset of layers and the second subset of layers being disposed on the substrate in an alternating layer order; The first subset of the layer includes aluminum nitride (AlN). The second subset of the layers includes helium-containing silicon hydride (Si:H-He); and The configuration of the layer assembly has an effective refractive index greater than or equal to 3.7; The net stress of the layer assembly is approximately zero MPa.

16. The optical interference filter of claim 15, wherein the stress of the first subset of the layer is between -1000 MPa and 150 MPa.

17. The optical interference filter of claim 15, wherein for light with wavelengths between 500 nm and 5500 nm, the refractive index of a first subset of the layer is between 1.9 and 2.2.

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