# US 12,761,433 B2 · Photodetectors with an integrated waveguide core > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,761,433 B2 - Document ID: US12761433B2 - Status: Granted - Kind: B2 - Application number: 18/405,727 - Filed: 2024-01-05 - Published: 2025-07-10 - Granted: 2026-10-13 - Earliest claimed: 2024-01-05 - Assignees: GlobalFoundries U.S. Inc. - Applicants: GlobalFoundries U.S. Inc. - Inventors: Yusheng Bian; Sujith Chandran; Won Suk Lee; Abdelsalam Aboketaf - Web page: https://patentgrep.com/patent/US12761433B2 ## CPC - G02B 6/4295: {coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Structures for a photonics chip that include a photodetector and methods of forming such structures. The structure comprises a photodetector including a pad and a semiconductor layer on the pad. The pad includes a side edge and a first waveguide core that extends from the side edge adjacent to the semiconductor layer. The structure further comprises a second waveguide core including a section adjoined to the side edge of the pad adjacent to the first waveguide core. ## Claims ### Claim 1 A structure for a photonics chip, the structure comprising: a photodetector including a pad and a semiconductor layer on the pad, the pad including a first side edge and a first waveguide core that extends from the first side edge adjacent to the semiconductor layer, the semiconductor layer having a longitudinal axis, and the first waveguide core including a longitudinal axis that is inclined relative to the longitudinal axis of the semiconductor layer; and a second waveguide core including a section adjoined to the first side edge of the pad adjacent to the first waveguide core. ### Claim 2 (depends on 1) The structure of claim 1 wherein the first waveguide core is laterally offset along the first side edge relative to the longitudinal axis of the semiconductor layer. ### Claim 3 (depends on 2) The structure of claim 2 wherein the pad includes a first trench and a second trench, and the first waveguide core is disposed between the first trench and the second trench, the first trench and the second trench penetrate partially through a thickness of the pad, the first waveguide core comprises a semiconductor material having a first refractive index, and the first trench and the second trench are filled by a dielectric material having a second refractive index that is less than the first refractive index. ### Claim 4 (depends on 1) The structure of claim 1 wherein the pad includes a first trench and a second trench, and the first waveguide core is disposed between the first trench and the second trench. ### Claim 5 (depends on 4) The structure of claim 4 wherein the first trench and the second trench penetrate partially through a thickness of the pad. ### Claim 6 (depends on 4) The structure of claim 4 wherein the first waveguide core comprises a semiconductor material having a first refractive index, and the first trench and the second trench are filled by a dielectric material having a second refractive index that is less than the first refractive index. ### Claim 7 (depends on 6) The structure of claim 6 wherein the pad comprises the semiconductor material. ### Claim 8 (depends on 4) The structure of claim 4 wherein the semiconductor layer includes a first sidewall adjacent to the first waveguide core and a second sidewall, the first trench and the second trench are disposed adjacent to the first sidewall, and the pad includes a third trench disposed adjacent to the second sidewall. ### Claim 9 (depends on 8) The structure of claim 8 wherein the first waveguide core comprises a semiconductor material having a first refractive index, and the first trench, the second trench, and the third trench are filled by a dielectric material having a second refractive index that is less than the first refractive index. ### Claim 10 (depends on 8) The structure of claim 8 wherein the pad includes a fourth trench disposed between the second sidewall and the third trench. ### Claim 11 (depends on 4) The structure of claim 4 wherein the semiconductor layer includes a first sidewall adjacent to the first waveguide core and a second sidewall, the first trench and the second trench are disposed adjacent to the first sidewall, and the pad includes a plurality of trenches disposed in a two-dimensional array adjacent to the second sidewall. ### Claim 12 (depends on 1) The structure of claim 1 wherein the second waveguide core is aligned with the first waveguide core at the first side edge of the pad. ### Claim 13 (depends on 1) The structure of claim 1 wherein the second waveguide core includes a slab layer. ### Claim 14 (depends on 1) The structure of claim 1 wherein the pad includes a third waveguide core that extends from the first side edge adjacent to the semiconductor layer, and further comprising: a fourth waveguide core including a section adjoined to the first side edge of the pad adjacent to the third waveguide core. ### Claim 15 (depends on 14) The structure of claim 14 wherein the semiconductor layer is disposed between the first waveguide core and the third waveguide core, and the third waveguide core includes a longitudinal axis that is inclined relative to the longitudinal axis of the semiconductor layer. ### Claim 16 (depends on 1) The structure of claim 1 wherein the pad includes a second side edge opposite from the first side edge and a third waveguide core that extends from the second side edge adjacent to the semiconductor layer, and further comprising: a fourth waveguide core including a section adjoined to the second side edge of the pad. ### Claim 17 (depends on 16) The structure of claim 16 wherein the semiconductor layer is disposed between the first waveguide core and the third waveguide core, and the third waveguide core includes a longitudinal axis that is inclined relative to the longitudinal axis of the semiconductor layer. ### Claim 18 (depends on 1) The structure of claim 1 further comprising: a third waveguide core disposed over the first waveguide core, wherein the first waveguide core comprises a first material, and the third waveguide core comprises a second material different from the first material. ### Claim 19 (depends on 1) The structure of claim 1 further comprising: a first doped region in the pad, the first doped region having a first conductivity type; and a second doped region in the pad, the second doped region having a second conductivity type opposite to the first conductivity type, wherein the semiconductor layer is disposed on a portion of the pad between the first doped region and the second doped region, and the portion of the pad comprises intrinsic semiconductor material. ### Claim 20 A method of forming a structure for a photonics chip, the method comprising: forming a photodetector that includes a pad and a semiconductor layer on the pad, wherein the pad includes a side edge and a first waveguide core that extends from the side edge adjacent to the semiconductor layer, the semiconductor layer has a longitudinal axis, and the first waveguide core includes a longitudinal axis that is inclined relative to the longitudinal axis of the semiconductor layer; and forming a second waveguide core that includes a section adjoined to the side edge of the pad adjacent to the first waveguide core.