Patents by Inventor Mahalingam Nandakumar

Mahalingam Nandakumar 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).

  • Publication number: 20240088262
    Abstract: A channel stop and well dopant migration control implant (e.g., of argon) can be used in the fabrication of a transistor (e.g., PMOS), either around the time of threshold voltage adjust and well implants prior to gate formation, or as a through-gate implant around the time of source/drain extension implants. With its implant depth targeted about at or less than the peak of the concentration of the dopant used for well and channel stop implants (e.g., phosphorus) and away from the substrate surface, the migration control implant suppresses the diffusion of the well and channel stop dopant to the surface region, a more retrograde concentration profile is achieved, and inter-transistor threshold voltage mismatch is improved without other side effects. A compensating through-gate threshold voltage adjust implant (e.g., of arsenic) or a threshold voltage adjust implant of increased dose can increase the magnitude of the threshold voltage to a desired level.
    Type: Application
    Filed: November 17, 2023
    Publication date: March 14, 2024
    Inventor: MAHALINGAM NANDAKUMAR
  • Patent number: 11869956
    Abstract: A channel stop and well dopant migration control implant (e.g., of argon) can be used in the fabrication of a transistor (e.g., PMOS), either around the time of threshold voltage adjust and well implants prior to gate formation, or as a through-gate implant around the time of source/drain extension implants. With its implant depth targeted about at or less than the peak of the concentration of the dopant used for well and channel stop implants (e.g., phosphorus) and away from the substrate surface, the migration control implant suppresses the diffusion of the well and channel stop dopant to the surface region, a more retrograde concentration profile is achieved, and inter-transistor threshold voltage mismatch is improved without other side effects. A compensating through-gate threshold voltage adjust implant (e.g., of arsenic) or a threshold voltage adjust implant of increased dose can increase the magnitude of the threshold voltage to a desired level.
    Type: Grant
    Filed: September 30, 2021
    Date of Patent: January 9, 2024
    Assignee: Texas Instruments Incorporated
    Inventor: Mahalingam Nandakumar
  • Publication number: 20240006230
    Abstract: A semiconductor device includes a trench extending into a semiconductor layer. A liner layer is on a sidewall of the semiconductor layer within the trench. The liner layer extends from the sidewall to a top surface of the semiconductor layer. An isolation structure is within the trench. The isolation structure is between a first region of the semiconductor layer and a second region of the semiconductor layer. The semiconductor layer includes a third region that couples the first region to the second region of the semiconductor layer. The third region of the semiconductor layer is substantially free of phosphorus contamination.
    Type: Application
    Filed: June 30, 2022
    Publication date: January 4, 2024
    Inventors: Mahalingam NANDAKUMAR, Douglas Harvey NEWMAN, Byron Joseph PALLA, Haowen BU
  • Publication number: 20230386923
    Abstract: Fabrication of an integrated circuit includes forming a photoresist layer over a substrate. Target regions defined on the substrate are exposed using a reticle that defines a first exposure window for a first doped structure of a first type; the first exposure window has a first plurality of openings and a first plurality of dopant blocking regions. A respective exposure dose for each of the target regions is determined by an exposure map and provides controlled variations in the size of the first plurality of openings across the plurality of target regions. Subsequent to the exposure and to developing the photoresist, a dopant is implanted into the substrate through the first plurality of openings.
    Type: Application
    Filed: August 8, 2023
    Publication date: November 30, 2023
    Inventor: Mahalingam Nandakumar
  • Publication number: 20230326954
    Abstract: A method of forming an integrated circuit includes first forming a resistor body and a transistor gate from a semiconductor layer over a substrate. Second, sidewall spacers are formed adjacent the resistor body and the transistor gate. Third, a silicide blocking structure is formed over at least a portion of the resistor body. And fourth, the resistor body and the transistor gate are concurrently millisecond annealed.
    Type: Application
    Filed: April 6, 2022
    Publication date: October 12, 2023
    Inventor: Mahalingam Nandakumar
  • Patent number: 11764111
    Abstract: Fabrication of an integrated circuit includes forming a photoresist layer over a substrate. Target regions defined on the substrate are exposed using a reticle that defines a first exposure window for a first doped structure of a first type; the first exposure window has a first plurality of openings and a first plurality of dopant blocking regions. A respective exposure dose for each of the target regions is determined by an exposure map and provides controlled variations in the size of the first plurality of openings across the plurality of target regions. Subsequent to the exposure and to developing the photoresist, a dopant is implanted into the substrate through the first plurality of openings.
    Type: Grant
    Filed: October 24, 2019
    Date of Patent: September 19, 2023
    Assignee: Texas Instruments Incorporated
    Inventor: Mahalingam Nandakumar
  • Publication number: 20230290775
    Abstract: A semiconductor device includes a resistor having a resistor body including polysilicon, with fluorine in the polysilicon. The resistor body has a laterally alternating distribution of silicon grain sizes. The semiconductor device further includes an MOS transistor having a gate including polysilicon with fluorine. The fluorine in the gate has a higher average concentration than the fluorine in the resistor body. The semiconductor device may be formed by forming a gate/resistor layer including polysilicon. A fluorine implant mask is formed over the gate/resistor layer, exposing the gate/resistor layer in an area for the gate and over implant segments in an area for the resistor body. The implant segments do not cover the entire area for the resistor body. Fluorine is implanted into the gate/resistor layer where exposed by the fluorine implant mask. The gate/resistor layer is patterned to form the gate and the resistor body.
    Type: Application
    Filed: May 15, 2023
    Publication date: September 14, 2023
    Inventors: Mahalingam Nandakumar, Yanbiao Pan
  • Publication number: 20230245891
    Abstract: A system and method for growing fine grain polysilicon. In one example, the method of forming an integrated circuit includes forming a dielectric layer over a semiconductor substrate, and forming a polysilicon layer over the dielectric layer. The polysilicon layer is formed by a chemical vapor deposition process that includes providing a gas flow including disilane and hydrogen gas over the semiconductor substrate.
    Type: Application
    Filed: January 31, 2022
    Publication date: August 3, 2023
    Inventors: Bhaskar Srinivasan, Pushpa Mahalingam, Mahalingam Nandakumar, Mona Eissa, Corinne Gagnet, Christopher Whitesell
  • Publication number: 20230230975
    Abstract: The present disclosure provides a method for forming a semiconductor device containing MOS transistors both with and without source/drain extension regions in a semiconductor substrate having a semiconductor material on either side of a gate structure including a gate electrode on a gate dielectric formed in a semiconductor material. In devices with source/drain extensions, a diffusion suppression species of one or more of indium, carbon and a halogen are used. The diffusion suppression implant can be selectively provided only to the semiconductor devices with drain extensions while devices without drain extensions remain diffusion suppression implant free.
    Type: Application
    Filed: March 23, 2023
    Publication date: July 20, 2023
    Inventors: Mahalingam Nandakumar, Brian Edward Hornung
  • Patent number: 11676961
    Abstract: A semiconductor device includes a resistor having a resistor body including polysilicon, with fluorine in the polysilicon. The resistor body has a laterally alternating distribution of silicon grain sizes. The semiconductor device further includes an MOS transistor having a gate including polysilicon with fluorine. The fluorine in the gate has a higher average concentration than the fluorine in the resistor body. The semiconductor device may be formed by forming a gate/resistor layer including polysilicon. A fluorine implant mask is formed over the gate/resistor layer, exposing the gate/resistor layer in an area for the gate and over implant segments in an area for the resistor body. The implant segments do not cover the entire area for the resistor body. Fluorine is implanted into the gate/resistor layer where exposed by the fluorine implant mask. The gate/resistor layer is patterned to form the gate and the resistor body.
    Type: Grant
    Filed: November 1, 2020
    Date of Patent: June 13, 2023
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Yanbiao Pan
  • Publication number: 20230154971
    Abstract: Methods and semiconductor circuits are described in which a polysilicon resistor body is formed over a semiconductor substrate. A first dopant species is implanted into the polysilicon resistor body at a first angle about parallel to a surface normal of a topmost surface of the polysilicon resistor body. A second dopant species is implanted into the polysilicon resistor body at a second angle greater than about 10° relative to the surface normal. The combination of implants reduces the different between the temperature coefficient (tempco) of resistance of narrow resistors relative to the tempco of wide resistors, and brings the tempco of the resistors closer to a preferred value of zero.
    Type: Application
    Filed: January 6, 2023
    Publication date: May 18, 2023
    Inventor: Mahalingam Nandakumar
  • Publication number: 20230141752
    Abstract: An integrated circuit includes a polysilicon resistor having a plurality of segments, including first, second and third segments, the second segment located between and running about parallel to the first and third segments. A first header connects the first and second segments, and a second header connects the second and third segments. A first metal silicide layer located over the first header extends over the first and second segments toward the second header. A second metal silicide layer located over the second header extends over the second and third segments toward the first header. A dielectric layer is located over and contacts the first, second and third segments between the first and second metal silicide layers.
    Type: Application
    Filed: January 6, 2023
    Publication date: May 11, 2023
    Inventor: Mahalingam Nandakumar
  • Publication number: 20230095534
    Abstract: A channel stop and well dopant migration control implant (e.g., of argon) can be used in the fabrication of a transistor (e.g., PMOS), either around the time of threshold voltage adjust and well implants prior to gate formation, or as a through-gate implant around the time of source/drain extension implants. With its implant depth targeted about at or less than the peak of the concentration of the dopant used for well and channel stop implants (e.g., phosphorus) and away from the substrate surface, the migration control implant suppresses the diffusion of the well and channel stop dopant to the surface region, a more retrograde concentration profile is achieved, and inter-transistor threshold voltage mismatch is improved without other side effects. A compensating through-gate threshold voltage adjust implant (e.g., of arsenic) or a threshold voltage adjust implant of increased dose can increase the magnitude of the threshold voltage to a desired level.
    Type: Application
    Filed: September 30, 2021
    Publication date: March 30, 2023
    Inventor: MAHALINGAM NANDAKUMAR
  • Patent number: 11616058
    Abstract: The present disclosure provides a method for forming a semiconductor device containing MOS transistors both with and without source/drain extension regions in a semiconductor substrate having a semiconductor material on either side of a gate structure including a gate electrode on a gate dielectric formed in a semiconductor material. In devices with source/drain extensions, a diffusion suppression species of one or more of indium, carbon and a halogen are used. The diffusion suppression implant can be selectively provided only to the semiconductor devices with drain extensions while devices without drain extensions remain diffusion suppression implant free.
    Type: Grant
    Filed: December 10, 2020
    Date of Patent: March 28, 2023
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Brian Edward Hornung
  • Patent number: 11588008
    Abstract: An integrated circuit includes a polysilicon resistor having a plurality of segments, including first, second and third segments, the second segment located between and running about parallel to the first and third segments. A first header connects the first and second segments, and a second header connects the second and third segments. A first metal silicide layer located over the first header extends over the first and second segments toward the second header. A second metal silicide layer located over the second header extends over the second and third segments toward the first header. A dielectric layer is located over and contacts the first, second and third segments between the first and second metal silicide layers.
    Type: Grant
    Filed: February 25, 2020
    Date of Patent: February 21, 2023
    Assignee: Texas Instruments Incorporated
    Inventor: Mahalingam Nandakumar
  • Patent number: 11581399
    Abstract: Methods and semiconductor circuits are described in which a polysilicon resistor body is formed over a semiconductor substrate. A first dopant species is implanted into the polysilicon resistor body at a first angle about parallel to a surface normal of a topmost surface of the polysilicon resistor body. A second dopant species is implanted into the polysilicon resistor body at a second angle greater than about 10° relative to the surface normal. The combination of implants reduces the different between the temperature coefficient (tempco) of resistance of narrow resistors relative to the tempco of wide resistors, and brings the tempco of the resistors closer to a preferred value of zero.
    Type: Grant
    Filed: June 30, 2020
    Date of Patent: February 14, 2023
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventor: Mahalingam Nandakumar
  • Publication number: 20220375856
    Abstract: A method and an electronic device that includes an isolation structure having a dielectric material on or in a semiconductor surface layer, and a passive circuit component having a metal silicide structure on a side of the isolation structure, there the metal silicide structure includes a metal silicide portion and a dielectric portion, the dielectric portion of the metal silicide structure including one of silicon nitride, silicon oxide, silicon carbide, silicon carbon nitride, and silicon oxynitride. The method includes forming a dielectric material of the isolation structure on or in the semiconductor surface layer, forming a silicon-rich dielectric layer on a side of the isolation structure, and siliciding the silicon-rich dielectric layer to form the metal silicide structure on the side of the isolation structure.
    Type: Application
    Filed: September 30, 2021
    Publication date: November 24, 2022
    Applicant: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Yuguo Wang, Haowen Bu
  • Patent number: 11455452
    Abstract: The present disclosure provides a method for adjusting implant parameter conditions in semiconductor processing by wafer and by wafer zone using in-line measurements from previous operations and a feed-forward computer model. The feed-forward model is based on a sensitivity map of in-line measured data and its effect of electrical performance. Feed-forward computer models that adjust implant parameters by wafer and by zone improve both wafer-to-wafer and within wafer electrical uniformity in semiconductor devices.
    Type: Grant
    Filed: July 31, 2020
    Date of Patent: September 27, 2022
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Mahalingam Nandakumar, Murlidhar Bashyam, Alwin Tsao, Douglas Newman
  • Publication number: 20220208973
    Abstract: A semiconductor device including drain extended metal oxide semiconductor field effect transistor (MOSFET) includes a source region and a drain region each having a first dopant type spaced apart along a surface of a semiconductor material having a second opposite conductivity type. A gate electrode over the semiconductor material surface between the source region and the drain region. A diffusion suppression implant region in the semiconductor material extends from the source region under the gate electrode. The diffusion suppression implant region includes a body region having the second opposite conductivity type and comprises at least one of carbon, nitrogen, and fluorine.
    Type: Application
    Filed: January 24, 2021
    Publication date: June 30, 2022
    Applicant: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Alexei Sadovnikov, Henry Litzmann Edwards, Jarvis Benjamin Jacobs
  • Publication number: 20220209012
    Abstract: An integrated circuit is fabricated by forming transistors having gates of orthogonal orientations and implanting, at two first rotations, a first pocket implant using a first dopant type with a masking pattern on a substrate surface layer, the two first rotations respectively forming two first pocket implantation angles and two first pocket implantation beam orientations, and implanting, at two second rotations, a retrograde gate-edge diode leakage (GDL) reduction pocket implant using a second dopant type with the masking pattern on the substrate surface layer, the two second rotations respectively forming two GDL-reduction implantation angles and two GDL-reduction implantation beam orientations.
    Type: Application
    Filed: December 28, 2020
    Publication date: June 30, 2022
    Inventors: Brian Edward Hornung, Mahalingam Nandakumar