Color filters including infrared cut-off integrated on CMOS image sensor

Frey, Laurent; Parrein, Pascale; Raby, Jacques; Pelle, Catherine; Hérault, Didier; Marty, M.; Michailos, Jean

doi:10.1364/oe.19.013073

Cited by 69 publications

(44 citation statements)

References 7 publications

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“…1 The scalability of CIS technology has enabled lateral pixel size to be reduced from more than 10 µm to less than 2 µm in the last decade. 2,3 Along with scaling of the pixel size, there have been considerable efforts to redesign color filters, [4][5][6] microlenses, 7 and infrared filters 8 to prevent the degradation of the optical performance. Dye-doped polymers have been conventionally used for RGB color filters in digital color imaging.…”

Section: Introductionmentioning

confidence: 99%

Visible Wavelength Color Filters Using Dielectric Subwavelength Gratings for Backside-Illuminated CMOS Image Sensor Technologies

et al. 2017

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We report transmissive color filters based on subwavelength dielectric gratings that can replace conventional dye-based color filters used in backside-illuminated CMOS image sensor (BSI CIS) technologies. The filters are patterned in an 80-nm-thick poly-silicon film on a 115-nm-thick SiO 2 spacer layer. They are optimized for operating at the primary RGB colors, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 exhibit peak transmittance of 60-80%, and an almost insensitive response over a ±20 • angular range. This technology enables shrinking of the pixel sizes down to near a micrometer. KeywordsSubwavelength grating, high-index contrast, color filters, CMOS image sensor Scalability of complementary metal oxide transistor (CMOS) technology has improved the performance of CMOS image sensors (CIS) in the past decade. One of the trends in the CIS technology, driven mainly by portable devices with small form-factors, is to decrease the pixel size, which will lead to improved spatial resolution for digital imaging. 1 The scalability of CIS technology has enabled lateral pixel size to be reduced from more than 10 µm to less than 2 µm in the last decade. 2,3 Along with scaling of the pixel size, there have been considerable efforts to redesign color filters, 4-6 microlenses, 7 and infrared filters 8 to prevent the degradation of the optical performance. Dye-doped polymers have been conventionally used for RGB color filters in digital color imaging. However, when the pixel size gets smaller, the optical crosstalk among pixels becomes significant because of the small absorption coefficient of the organic dyes. Besides, the dye-doped polymers are essentially photoresists that degrade under ultraviolet illumination or high temperature environments. To address these issues, plasmonic color filters made of metallic thin films with subwavelength patterning have been studied for CIS technology. 5,9,10 The plasmonic color filters have several advantages such as flexible color tunability across visible spectrum and compatibility with CMOS processes. However, the absolute efficiency of the plasmonic color filters is relatively low (40-50% range) compared to conventional organic dye-doped filters. Here, we show that dielectric subwavelength gratings can be used to achieve highly efficient transmission color filters with close to angular insensitive properties. Furthermore, compared to dye-based filters, our dielectric-based filters possess better reliability under ultraviolet illumination and at high temperature. For the optimized filter designs, we take the advantage of the backside-illumination (BSI) CIS technologies, where the color filter layer can be placed in close proximity to the photodiodes 2 16 anti-reflection coating, 17,18 and reflective-transmission filters for displays. 19 In this letter, we demonstrate designs for polarizatio...

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Section: Introductionmentioning

confidence: 99%

Visible Wavelength Color Filters Using Dielectric Subwavelength Gratings for Backside-Illuminated CMOS Image Sensor Technologies

et al. 2017

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“…Chief among these are their subwavelength dimensions (leading to ultradense, ultrathin pixel arrays), and their long-term environmental stability (they do not degrade or fade over time due to radiation exposure). As a result, plasmonic filters have been positioned as new technological solutions for subwavelength color printing, [1,4,[7][8][9]12] anticounterfeiting measures, [19,20] and RGB splitting for image sensors; [2,17,21,22] thus representing one of the most promising, technologically relevant areas of current plasmonic research activity. Here, we explore a new application of polarizationcontrolled plasmonic filters: dual output, full-color optical image encoding.…”

mentioning

confidence: 99%

Plasmonic Color Filters as Dual‐State Nanopixels for High‐Density Microimage Encoding

Heydari

Sperling

Neale

et al. 2017

Adv Funct Materials

112

110

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Plasmonic color filtering has provided a range of new techniques for "printing" images at resolutions beyond the diffraction-limit, significantly improving upon what can be achieved using traditional, dye-based filtering methods. Here, a new approach to high-density data encoding is demonstrated using full color, dual-state plasmonic nanopixels, doubling the amount of information that can be stored in a unit-area. This technique is used to encode two data sets into a single set of pixels for the first time, generating vivid, near-full sRGB (standard Red Green Blue color space)color images and codes with polarization-switchable information states. Using a standard optical microscope, the smallest "unit" that can be read relates to 2 × 2 nanopixels (370 nm × 370 nm). As a result, dual-state nanopixels may prove significant for long-term, high-resolution optical image encoding, and counterfeit-prevention measures. over their microscale, dye-based counterparts. Chief among these are their subwavelength dimensions (leading to ultradense, ultrathin pixel arrays), and their long-term environmental stability (they do not degrade or fade over time due to radiation exposure). As a result, plasmonic filters have been positioned as new technological solutions for subwavelength color printing, [1,4,[7][8][9]12] anticounterfeiting measures, [19,20] and RGB splitting for image sensors; [2,17,21,22] thus representing one of the most promising, technologically relevant areas of current plasmonic research activity. Here, we explore a new application of polarizationcontrolled plasmonic filters: dual output, full-color optical image encoding. Recent developments in the engineering and manipulation of materials on the nanoscale have given rise to a number of new techniques with the potential for physically encoding data and images into optically readable volumes and surfaces. [23,24] Using semiconductor quantum dots, [25][26][27] graphene, [28] and various super-resolution lithography techniques, [29][30][31][32][33][34] researchers are demonstrating novel 2D and 3D techniques that may enable the next generation of optical storage and encoding technologies. Plasmonic particles and filters have also seen applications in these research areas, with the aforementioned image encoding examples having been joined by demonstrations of their use in optical data storage. [23,24,[35][36][37] Here, we show a new utilization of image encoding using polarization multiplexed plasmonic filters, where, unlike previous studies that employed color or position switching in fixed images, [14,38] we show that two arbitrary, full-color images can be encoded into a single array of pixels. Our individual pixels are comprised of asymmetric cross-shaped nanoapertures in a thin film of aluminum. Each aperture is engineered to exhibit two independent plasmonic resonances which can be tuned across the sRGB (standard Red Green Blue) color-space (a single pixel can be encoded with any two arbitrary colors). We go on to show that by using the smallest visible unit ...

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“…Plasmonic hole and slit array color filters have been demonstrated as a viable alternative to dye-based filters for RGB and CMYK color-filtering [3][4][5][6][7][8]. In addition to hole and slit array filters, many other geometries have been explored as potential platforms for commercially viable plasmonic color filters [9][10][11][12]. Recently, this spate of development has been translated into industrial CMOS image sensor prototypes and are actively being considered for full commercialization [13].…”

Section: Introductionmentioning

confidence: 99%

Hyper-selective plasmonic color filters

Fleischman¹,

Sweatlock²,

Murakami³

et al. 2017

Opt. Express

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Abstract:The subwavelength mode volumes of plasmonic filters are well matched to the small size of state-of-the-art active pixels in CMOS image sensor arrays used in portable electronic devices. Typical plasmonic filters exhibit broad (> 100 nm) transmission bandwidths suitable for RBG or CMYK color filtering. Dramatically reducing the peak width of filter transmission spectra would allow for the realization of CMOS image sensors with multi-and hyperspectral imaging capabilities. We find that the design of 5 layer metalinsulator-metal-insulator-metal structures gives rise to multi-mode interference phenomena that suppress spurious transmission features and give rise to single transmission bands as narrow as 17 nm. The transmission peaks of these multilayer slot-mode plasmonic filters (MSPFs) can be systematically varied throughout the visible and near infrared spectrum, leading to a filter that is CMOS integrable, since the same basic MSPF structure can operate over a large range of wavelengths. We find that MSPF filter designs that can achieve a bandwidth less than 30 nm across the visible and demonstrate experimental prototypes with a FWHM of 70 nm, and we describe how experimental structure can be made to approach the limits suggested by the model.

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Color filters including infrared cut-off integrated on CMOS image sensor

Cited by 69 publications

References 7 publications

Visible Wavelength Color Filters Using Dielectric Subwavelength Gratings for Backside-Illuminated CMOS Image Sensor Technologies

Visible Wavelength Color Filters Using Dielectric Subwavelength Gratings for Backside-Illuminated CMOS Image Sensor Technologies

Plasmonic Color Filters as Dual‐State Nanopixels for High‐Density Microimage Encoding

Hyper-selective plasmonic color filters

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