# US 9,753,226 B2 · Photonics grating coupler and method of manufacture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,226 B2 - Document ID: US9753226B2 - Status: Granted - Kind: B2 - Application number: 14/976,677 - Filed: 2015-12-21 - Published: 2016-04-21 - Granted: 2017-09-05 - Earliest claimed: 2013-03-14 - Assignees: Micron Technology, Inc. - Applicants: Micron Technology, Inc. - Inventors: Harel Frish - Web page: https://patentgrep.com/patent/US9753226B2 ## CPC - G02B 6/30: for use between fibre and thin-film device - G02B 6/122: Basic optical elements, e.g. light-guiding paths - G02B 6/124: Geodesic lenses or integrated gratings - G02B 6/13: Integrated optical circuits characterised by the manufacturing method - G02B 6/132: by deposition of thin films - G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)} - G02B 6/3628: {for mounting fibres to supporting carriers (G02B6/3608, G02B6/3616 take precedence)} - B29D 11/00663: {Production of light guides} - C03C 3/04: containing silica - C03C 15/00: Surface treatment of glass, not in the form of fibres or filaments, by etching (etching or surface-brightening compositions, in general C09K13/00) - G02B 5/1857: {using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams} - G02B 2006/12061: {Silicon} - G02B 2006/12092: {Stepped} - G03F 7/0005: {Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract A structure for coupling an optical signal between an integrated circuit photonic structure and an external optical fiber is disclosed as in a method of formation. The coupling structure is sloped relative to a horizontal surface of the photonic structure such that light entering or leaving the photonic structure is substantially normal to its upper surface. ## Claims ### Claim 1 A method of forming a photonic structure, the method comprising: forming a lower cladding material over an upper surface of a supporting substrate; forming a waveguide core having a horizontal portion and a contiguous sloped portion over the lower cladding material; and forming an optical grating in the sloped portion of the waveguide core, the sloped portion and the optical grating configured such that light emitted by the grating is in a direction substantially normal to a surface of the horizontal portion of the waveguide core. ### Claim 2 (depends on 1) A method as in claim 1 wherein the optical grating emits a light wave in a first direction which is substantially normal to the direction of light travel in the horizontal portion. ### Claim 3 (depends on 1) A method as in claim 1 wherein the sloped portion of the waveguide core has a sloped angle relative to the horizontal portion which causes light emitted by the grating to be in a direction substantially normal to an upper surface of the horizontal portion of the waveguide core. ### Claim 4 (depends on 3) A method as in claim 3 wherein forming the optical grating comprises forming a plurality of spaced grooves in an upper surface of the sloped portion of the waveguide core. ### Claim 5 (depends on 4) A method as in claim 4 wherein the plurality of spaced grooves in the upper surface of the waveguide core each have a depth in the range of about 270 nm to about 280 nm. ### Claim 6 (depends on 5) A method as in claim 5, wherein the plurality of spaced grooves have a period of about 498 nm. ### Claim 7 (depends on 6) A method as in claim 6, wherein the waveguide core comprises a material selected from the group consisting of Si, Si3N4, SiOxN4, SiC, SixGey, GaAs, AlGaAs, InGaAs, and InP, where x and y are positive integers. ### Claim 8 (depends on 1) A method as in claim 1, further comprising forming an upper cladding material on the sides and over the waveguide core; forming grooves in the upper cladding material which extend into the sloped portion of the waveguide core to form the optical grating; and filling the grooves with an additional upper cladding material. ### Claim 9 (depends on 8) A method as in claim 8 wherein the additional upper cladding material is also provided over the upper cladding material and provides an upper surface of the photonic structure, wherein light emitted by the optical grating is substantially normal to the upper surface of the additional upper cladding material. ### Claim 10 (depends on 8) A method as in claim 8, wherein the additional upper cladding material is planarized down to the upper surface of the upper cladding material. ### Claim 11 A method of forming a photonic coupler, the method comprising: forming a lower cladding material over an upper surface of a supporting substrate, the lower cladding material having a horizontal portion and a sloped portion coupled to the horizontal portion; forming a waveguide core material over the lower cladding material such that the waveguide core material has a horizontal portion and a sloped portion coupled to the horizontal portion; and forming a grating coupler in the sloped portion of the waveguide core such that the grating coupler is configured to transmit or receive light passing through the waveguide core. ### Claim 12 (depends on 11) The method of claim 11, further comprising forming an upper cladding material over the waveguide core such that the upper cladding material has a flat upper surface substantially parallel to the horizontal portion of the waveguide core. ### Claim 13 (depends on 12) The method of claim 12 wherein the upper cladding material comprises an anti-reflective coating material. ### Claim 14 (depends on 12) The method of claim 12 wherein forming the grating coupler comprises forming spaced grooves extending through the upper cladding material and into the sloped portion of the waveguide core. ### Claim 15 (depends on 14) The method of claim 14, further comprising forming an additional cladding material within the grooves of the upper cladding material and grooves of the sloped portion of the waveguide core. ### Claim 16 A photonic structure comprising: a substrate; a photonic element supported by the substrate and having a horizontal portion and a sloped portion coupled to the horizontal portion; and a grating formed at the sloped portion for directing light into or out of the photonic element, wherein the direction of light travel out of the grating is substantially normal to the direction of travel of light in the horizontal portion of the photonic element, wherein the sloped portion of the waveguide core is in the range of about 8 to about 12degrees with respect to the horizontal portion of the waveguide core. ### Claim 17 (depends on 16) The photonic structure of claim 16 wherein the photonic element is a waveguide core. ### Claim 18 (depends on 17) The photonic structure of claim 17 wherein the waveguide core is formed of silicon. ### Claim 19 (depends on 17) The photonic structure of claim 17 wherein the material of the waveguide core comprises silicon nitride. ### Claim 20 (depends on 16) The photonic structure of claim 16 wherein the material of the waveguide core comprises silicon oxynitride.