Photodetector array with diffraction gratings having different pitches
AssigneeGlobalFoundries U.S. Inc.
InventorsYusheng Bian, Siva P. Adusumilli, Mark D. Levy
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Abstract
A photodetector array includes a substrate, and an array of pixels over the substrate. Each pixel includes a set of diffraction gratings directly on a semiconductor photodetector. A pitch of the set of diffraction gratings associated with each pixel in the array of pixels are different to enable each pixel to detect a specific wavelength of light different than other pixels of the array of pixels. An air cavity may be provided in the substrate under the germanium photodetector to improve light absorption. A method of forming the photodetector array is also disclosed.
Claims19
A structure, comprising:
- a substrate;
- an array of pixels over the substrate, each pixel including a set of diffraction gratings directly on a semiconductor photodetector;
- and
- an air cavity under at least one semiconductor photodetector in the substrate;
- wherein a pitch of the set of diffraction gratings associated with each pixel in the array of pixels are different to enable each pixel to detect a specific wavelength of light different than other pixels of the array of pixels.
A structure, comprising:
- a substrate;
- an array of pixels over the substrate, each pixel including a set of diffraction gratings directly on a semiconductor photodetector, wherein each set of diffraction gratings includes one of poly silicon and silicon;
- a trench isolation about each semiconductor photodetector;
- and
- an air cavity under at least one semiconductor photodetector in the substrate,
- wherein a pitch of the set of diffraction gratings associated with each pixel in the array of pixels are different to enable each pixel to detect a specific wavelength of light different than other pixels of the array of pixels such that the array of pixels absorbs greater than one wavelength of light.
A method, comprising:
- forming an array of pixels on a substrate, by:
- forming an array of semiconductor photodetectors on a substrate, the array of semiconductor photodetectors surrounded by a trench isolation;
- and
- forming a set of diffraction gratings directly on each semiconductor photodetector to create the array of pixels, wherein a pitch of the set of diffraction gratings associated with each semiconductor photodetector is different to enable each pixel to detect a specific wavelength of light different than other pixels of the array of pixels.
Dependencies are inferred from the claim text.