Patents by Inventor Rishikesh Krishnan

Rishikesh Krishnan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11888048
    Abstract: A method of forming a semiconductor structure includes forming a first nanosheet stack and a second nanosheet stack on a semiconductor substrate. The first nanosheet stack includes a plurality of alternating first sacrificial layers and first channel layers. The first sacrificial layers each define a first sacrificial height. The second nanosheet stack includes a plurality of alternating second sacrificial layers and second channel layers. The second sacrificial layers each define a second sacrificial height greater than the first sacrificial height of the first sacrificial layers. The method further includes removing the first and second sacrificial layers respectively from the first and second nanosheet stacks. A metal gate is deposited over the first and second nanosheet stacks to form respective first and second nanosheet transistor structures.
    Type: Grant
    Filed: November 9, 2021
    Date of Patent: January 30, 2024
    Assignee: International Business Machines Corporation
    Inventors: Shahab Siddiqui, Koji Watanabe, Charlotte DeWan Adams, Kai Zhao, Daniel James Dechene, Rishikesh Krishnan
  • Publication number: 20230178553
    Abstract: A semiconductor structure is provided that includes a first FET device stacked over a second FET device, wherein the first FET device contains a first functional gate structure containing a first work function metal and the second FET device contains a second functional gate structure containing a second work function metal. In the structure, the first work function metal is absent from an area including the second work function metal, and vice versa. Thus, no shared work functional metal is present in the semiconductor structure.
    Type: Application
    Filed: December 8, 2021
    Publication date: June 8, 2023
    Inventors: Ruilong Xie, Julien Frougier, Junli Wang, Dechao Guo, Ruqiang Bao, Rishikesh Krishnan, Balasubramanian S. Pranatharthiharan
  • Publication number: 20230100113
    Abstract: Integrated chips and methods of forming the same include forming a stack of layers, including a device stack above a first sacrificial layer, above a substrate. The first sacrificial layer is replaced with a first etch stop layer. The substrate is removed, exposing a substrate-side of the stack of layers. The substrate-side of the stack of layers is etched to form a trench, stopping on the first etch stop layer. A conductive line is formed in the trench.
    Type: Application
    Filed: September 29, 2021
    Publication date: March 30, 2023
    Inventors: Ruilong Xie, Stuart Sieg, Somnath Ghosh, Kisik Choi, Rishikesh Krishnan, Alexander Reznicek
  • Publication number: 20230029561
    Abstract: Epitaxially grow first lower source-drain regions within a substrate. Portions of the substrate adjacent the lower regions are doped to form second lower source-drain regions. An undoped silicon layer is formed over the first and second lower regions. Etch completely through the undoped layer into the first and second lower regions to form fins and to define bottom junctions beneath the fins. The fins and bottom junctions define intermediate cavities. Form lower spacers, gates, and upper spacers in the cavities; form top junctions on outer surfaces of the fins; and form epitaxially grown first upper source-drain regions outward of the upper spacers and opposite the first lower regions. The first upper regions are doped the same as the first lower regions. Form second upper source-drain regions outward of the upper spacers and opposite the second lower regions; these are doped the same as the second lower regions.
    Type: Application
    Filed: October 15, 2022
    Publication date: February 2, 2023
    Inventors: Kai Zhao, Shahab Siddiqui, Daniel James Dechene, Rishikesh Krishnan, Charlotte DeWan Adams
  • Patent number: 11515427
    Abstract: Epitaxially grow first lower source-drain regions within a substrate. Portions of the substrate adjacent the lower regions are doped to form second lower source-drain regions. An undoped silicon layer is formed over the first and second lower regions. Etch completely through the undoped layer into the first and second lower regions to form fins and to define bottom junctions beneath the fins. The fins and bottom junctions define intermediate cavities. Form lower spacers, gates, and upper spacers in the cavities; form top junctions on outer surfaces of the fins; and form epitaxially grown first upper source-drain regions outward of the upper spacers and opposite the first lower regions. The first upper regions are doped the same as the first lower regions. Form second upper source-drain regions outward of the upper spacers and opposite the second lower regions; these are doped the same as the second lower regions.
    Type: Grant
    Filed: June 15, 2020
    Date of Patent: November 29, 2022
    Assignee: International Business Machines Corporation
    Inventors: Kai Zhao, Shahab Siddiqui, Daniel James Dechene, Rishikesh Krishnan, Charlotte DeWan Adams
  • Publication number: 20220069104
    Abstract: A method of forming a semiconductor structure includes forming a first nanosheet stack and a second nanosheet stack on a semiconductor substrate. The first nanosheet stack includes a plurality of alternating first sacrificial layers and first channel layers. The first sacrificial layers each define a first sacrificial height. The second nanosheet stack includes a plurality of alternating second sacrificial layers and second channel layers. The second sacrificial layers each define a second sacrificial height greater than the first sacrificial height of the first sacrificial layers. The method further includes removing the first and second sacrificial layers respectively from the first and second nanosheet stacks. A metal gate is deposited over the first and second nanosheet stacks to form respective first and second nanosheet transistor structures.
    Type: Application
    Filed: November 9, 2021
    Publication date: March 3, 2022
    Inventors: Shahab Siddiqui, Koji Watanabe, Charlotte DeWan Adams, Kai Zhao, Daniel James Dechene, Rishikesh Krishnan
  • Patent number: 11211474
    Abstract: A method of forming a semiconductor structure includes forming a first nanosheet stack and a second nanosheet stack on a semiconductor substrate. The first nanosheet stack includes a plurality of alternating first sacrificial layers and first channel layers. The first sacrificial layers each define a first sacrificial height. The second nanosheet stack includes a plurality of alternating second sacrificial layers and second channel layers. The second sacrificial layers each define a second sacrificial height greater than the first sacrificial height of the first sacrificial layers. The method further includes removing the first and second sacrificial layers respectively from the first and second nanosheet stacks. A metal gate is deposited over the first and second nanosheet stacks to form respective first and second nanosheet transistor structures.
    Type: Grant
    Filed: January 14, 2020
    Date of Patent: December 28, 2021
    Assignee: International Business Machines Corporation
    Inventors: Shahab Siddiqui, Koji Watanabe, Charlotte DeWan Adams, Kai Zhao, Daniel James Dechene, Rishikesh Krishnan
  • Publication number: 20210391473
    Abstract: Epitaxially grow first lower source-drain regions within a substrate. Portions of the substrate adjacent the lower regions are doped to form second lower source-drain regions. An undoped silicon layer is formed over the first and second lower regions. Etch completely through the undoped layer into the first and second lower regions to form fins and to define bottom junctions beneath the fins. The fins and bottom junctions define intermediate cavities. Form lower spacers, gates, and upper spacers in the cavities; form top junctions on outer surfaces of the fins; and form epitaxially grown first upper source-drain regions outward of the upper spacers and opposite the first lower regions. The first upper regions are doped the same as the first lower regions. Form second upper source-drain regions outward of the upper spacers and opposite the second lower regions; these are doped the same as the second lower regions.
    Type: Application
    Filed: June 15, 2020
    Publication date: December 16, 2021
    Inventors: Kai Zhao, Shahab Siddiqui, Daniel James Dechene, Rishikesh Krishnan, Charlotte DeWan Adams
  • Patent number: 11081583
    Abstract: A device and method for forming a semiconductor device includes forming a gate structure on a channel region of fin structures and forming a flowable dielectric material on a source region portion and a drain region portion of the fin structures. The flowable dielectric material is present at least between adjacent fin structures of the plurality of fin structures filling a space between the adjacent fin structures. An upper surface of the source region portion and the drain region portion of fin structures is exposed. An epitaxial semiconductor material is formed on the upper surface of the source region portion and the drain region portion of the fin structures.
    Type: Grant
    Filed: October 28, 2019
    Date of Patent: August 3, 2021
    Assignee: International Business Machines Corporation
    Inventors: Eric C. Harley, Judson R. Holt, Yue Ke, Rishikesh Krishnan, Keith H. Tabakman, Henry K. Utomo
  • Publication number: 20210217873
    Abstract: A method of forming a semiconductor structure includes forming a first nanosheet stack and a second nanosheet stack on a semiconductor substrate. The first nanosheet stack includes a plurality of alternating first sacrificial layers and first channel layers. The first sacrificial layers each define a first sacrificial height. The second nanosheet stack includes a plurality of alternating second sacrificial layers and second channel layers. The second sacrificial layers each define a second sacrificial height greater than the first sacrificial height of the first sacrificial layers. The method further includes removing the first and second sacrificial layers respectively from the first and second nanosheet stacks. A metal gate is deposited over the first and second nanosheet stacks to form respective first and second nanosheet transistor structures.
    Type: Application
    Filed: January 14, 2020
    Publication date: July 15, 2021
    Inventors: Shahab Siddiqui, Koji Watanabe, Charlotte DeWan Adams, Kai Zhao, Daniel James Dechene, Rishikesh Krishnan
  • Patent number: 10886178
    Abstract: A device including a triple-layer EPI stack including SiGe, Ge, and Si, respectively, with Ga confined therein, and method of production thereof. Embodiments include an EPI stack including a SiGe layer, a Ge layer, and a Si layer over a plurality of fins, the EPI stack positioned between and over a portion of sidewall spacers, wherein the Si layer is a top layer capping the Ge layer, and wherein the Ge layer is a middle layer capping the SiGe layer underneath; and a Ga layer in a portion of the Ge layer between the SiGe layer and the Si layer.
    Type: Grant
    Filed: August 22, 2018
    Date of Patent: January 5, 2021
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Tek Po Rinus Lee, Annie Levesque, Qun Gao, Hui Zang, Rishikesh Krishnan, Bharat Krishnan, Curtis Durfee
  • Patent number: 10790198
    Abstract: The present disclosure relates to semiconductor structures and, more particularly, to fin structures and methods of manufacture. The structure includes: a plurality of fin structures formed of substrate material; a semiconductor material located between selected fin structures of the plurality of fin structures; and isolation regions within spaces between the plurality of fin structures.
    Type: Grant
    Filed: August 8, 2018
    Date of Patent: September 29, 2020
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Fuad H. Al-Amoody, Yiheng Xu, Rishikesh Krishnan
  • Patent number: 10615279
    Abstract: A method forming a semiconductor device that in one embodiment includes forming a gate structure on a channel region of fin structures, and forming a flowable dielectric material on a source region portion and a drain region portion of the fin structures. The flowable dielectric material is present at least between adjacent fin structures of the plurality of fin structures filling a space between the adjacent fin structures. An upper surface of the source region portion and the drain region portion of fin structures is exposed. An epitaxial semiconductor material is formed on the upper surface of the source region portion and the drain region portion of the fin structures.
    Type: Grant
    Filed: March 15, 2016
    Date of Patent: April 7, 2020
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Eric C. Harley, Judson R. Holt, Yue Ke, Rishikesh Krishnan, Keith H. Tabakman, Henry K. Utomo
  • Publication number: 20200066593
    Abstract: A device including a triple-layer EPI stack including SiGe, Ge, and Si, respectively, with Ga confined therein, and method of production thereof. Embodiments include an EPI stack including a SiGe layer, a Ge layer, and a Si layer over a plurality of fins, the EPI stack positioned between and over a portion of sidewall spacers, wherein the Si layer is a top layer capping the Ge layer, and wherein the Ge layer is a middle layer capping the SiGe layer underneath; and a Ga layer in a portion of the Ge layer between the SiGe layer and the Si layer.
    Type: Application
    Filed: August 22, 2018
    Publication date: February 27, 2020
    Inventors: Tek Po Rinus LEE, Annie LEVESQUE, Qun GAO, Hui ZANG, Rishikesh KRISHNAN, Bharat KRISHNAN, Curtis DURFEE
  • Publication number: 20200066908
    Abstract: A device and method for forming a semiconductor device includes forming a gate structure on a channel region of fin structures and forming a flowable dielectric material on a source region portion and a drain region portion of the fin structures. The flowable dielectric material is present at least between adjacent fin structures of the plurality of fin structures filling a space between the adjacent fin structures. An upper surface of the source region portion and the drain region portion of fin structures is exposed. An epitaxial semiconductor material is formed on the upper surface of the source region portion and the drain region portion of the fin structures.
    Type: Application
    Filed: October 28, 2019
    Publication date: February 27, 2020
    Inventors: ERIC C. HARLEY, JUDSON R. HOLT, YUE KE, RISHIKESH KRISHNAN, KEITH H. TABAKMAN, HENRY K. UTOMO
  • Publication number: 20200051867
    Abstract: The present disclosure relates to semiconductor structures and, more particularly, to fin structures and methods of manufacture. The structure includes: a plurality of fin structures formed of substrate material; a semiconductor material located between selected fin structures of the plurality of fin structures; and isolation regions within spaces between the plurality of fin structures.
    Type: Application
    Filed: August 8, 2018
    Publication date: February 13, 2020
    Inventors: Fuad H. AL-AMOODY, Yiheng XU, Rishikesh KRISHNAN
  • Patent number: 10243077
    Abstract: A method forming a semiconductor device that in one embodiment includes forming a gate structure on a channel region of fin structures, and forming a flowable dielectric material on a source region portion and a drain region portion of the fin structures. The flowable dielectric material is present at least between adjacent fin structures of the plurality of fin structures filling a space between the adjacent fin structures. An upper surface of the source region portion and the drain region portion of fin structures is exposed. An epitaxial semiconductor material is formed on the upper surface of the source region portion and the drain region portion of the fin structures.
    Type: Grant
    Filed: November 22, 2017
    Date of Patent: March 26, 2019
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Eric C. Harley, Judson R. Holt, Yue Ke, Rishikesh Krishnan, Keith H. Tabakman, Henry K. Utomo
  • Patent number: 10211045
    Abstract: An insulator is formed by flowable chemical vapor deposition (FCVD) process. The insulator is cured by exposing the insulator to ultraviolet light while flowing ozone over the insulator to produce a cured insulator. The curing process forms nitrogen, hydrogen, nitrogen monohydride, or hydroxyl-rich atomic clusters in the insulator. Following the curing process, these methods select wavelengths of microwave radiation (that will be subsequently used during annealing) so that such wavelengths excite the nitrogen, hydrogen, nitrogen monohydride, or hydroxyl-rich atomic clusters. Then, these methods anneal the cured insulator by exposing the cured insulator to microwave radiation in an inert (e.g., non-oxidizing) ambient atmosphere, at a temperature below 500° C., so as to increase the density of the cured insulator.
    Type: Grant
    Filed: January 24, 2018
    Date of Patent: February 19, 2019
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Rishikesh Krishnan, Joseph K. Kassim, Bharat V. Krishnan, Joseph F. Shepard, Jr., Rinus Tek Po Lee, Yiheng Xu
  • Publication number: 20190027556
    Abstract: A method of forming a shallow trench isolation (STI) for an integrated circuit (IC) structure to mitigate fin bending disclosed. The method may include forming a first insulator layer in a first portion of an opening in a substrate by a bottom-up atomic layer deposition (ALD) process; and forming a second insulator layer on the first insulator layer in a second portion of the opening. The opening may be position between a set of fins in the substrate. The method may further include forming an oxide liner in the opening before the forming the first insulator layer. The second insulator layer may be formed by deposition using a flowable chemical vapor deposition (FCVD) process, high aspect ratio process (HARP), high-density plasma chemical vapor deposition (HDP CVD) process, or any other conventional insulator material deposition process.
    Type: Application
    Filed: July 21, 2017
    Publication date: January 24, 2019
    Inventors: Jiehui Shu, Rishikesh Krishnan, Jinping Liu, Yiheng Xu, Joseph F. Shepard, JR.
  • Publication number: 20180097113
    Abstract: A method forming a semiconductor device that in one embodiment includes forming a gate structure on a channel region of fin structures, and forming a flowable dielectric material on a source region portion and a drain region portion of the fin structures. The flowable dielectric material is present at least between adjacent fin structures of the plurality of fin structures filling a space between the adjacent fin structures. An upper surface of the source region portion and the drain region portion of fin structures is exposed. An epitaxial semiconductor material is formed on the upper surface of the source region portion and the drain region portion of the fin structures.
    Type: Application
    Filed: November 22, 2017
    Publication date: April 5, 2018
    Inventors: ERIC C. HARLEY, JUDSON R. HOLT, YUE KE, RISHIKESH KRISHNAN, KEITH H. TABAKMAN, HENRY K. UTOMO