Patents by Inventor Siddarth A. Krishnan

Siddarth A. 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: 9859169
    Abstract: A method for fabricating a gate stack of a semiconductor device comprises forming a first dielectric layer over a channel region of the device, forming a first nitride layer over the first dielectric layer, forming a first gate metal layer over the first nitride layer, forming a capping layer over the first gate metal layer, removing portions of the capping layer and the first gate metal layer to expose a portion of the first nitride layer in a p-type field effect transistor (pFET) region of the gate stack, depositing a scavenging layer on the first nitride layer and the capping layer, depositing a second nitride layer on the scavenging layer, and depositing a gate electrode material on the second nitride layer.
    Type: Grant
    Filed: January 15, 2016
    Date of Patent: January 2, 2018
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Publication number: 20170358655
    Abstract: Semiconductor devices and methods of forming the same include forming a work function stack over semiconductor fins in a first region and a second region, the work function stack having a bottom layer, a middle layer, and a top layer. The work function stack is etched to remove the top layer and to decrease a thickness of the middle layer in the second region, leaving a portion of the middle layer and the bottom layer intact. A gate is formed over the semiconductor fins in the first and second regions.
    Type: Application
    Filed: June 8, 2016
    Publication date: December 14, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Patent number: 9824930
    Abstract: A method of fabricating advanced node field effect transistors using a replacement metal gate process. The method includes dopant a high-k dielectric directly or indirectly by using layers composed of multi-layer thin film stacks, or in other embodiments, by a single blocking layer. By taking advantage of unexpected etch selectivity of the multi-layer stack or the controlled etch process of a single layer stack, etch damage to the high-k may be avoided and work function metal thicknesses can be tightly controlled which in turn allows field effect transistors with low Tinv (inverse of gate capacitance) mismatch.
    Type: Grant
    Filed: August 10, 2016
    Date of Patent: November 21, 2017
    Assignee: International Business Machines Corporation
    Inventors: Takashi Ando, Hemanth Jagannathan, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon, Rekha Rajaram
  • Patent number: 9799656
    Abstract: A method for fabricating a gate stack of a semiconductor device comprises forming a first dielectric layer over a channel region of the device, forming a first nitride layer over the first dielectric layer, depositing a scavenging layer on the first nitride layer, forming a capping layer over the scavenging layer, removing portions of the capping layer and the scavenging layer to expose a portion of the first nitride layer in a n-type field effect transistor (nFET) region of the gate stack, forming a first gate metal layer over the first nitride layer and the capping layer, depositing a second nitride layer on the first gate metal layer, and depositing a gate electrode material on the second nitride layer.
    Type: Grant
    Filed: January 3, 2017
    Date of Patent: October 24, 2017
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Patent number: 9768171
    Abstract: A method of making a semiconductor device includes growing an interfacial layer on a substrate; depositing a first titanium nitride (TiN) layer on the interfacial layer; depositing a second TiN layer on the first TiN layer, the first TiN layer and the second TiN layer forming a bilayer work function gate stack of a first transistor; depositing a work function gate stack of a second transistor on the interfacial layer adjacent to the bilayer work function gate stack and on the bilayer work function stack; and depositing a gate electrode material on the work function gate stack of the second transistor.
    Type: Grant
    Filed: December 16, 2015
    Date of Patent: September 19, 2017
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Publication number: 20170263707
    Abstract: After forming a buried nanowire segment surrounded by a gate structure located on a substrate, an epitaxial source region is grown on a first end of the buried nanowire segment while covering a second end of the buried nanowire segment and the gate structure followed by growing an epitaxial drain region on the second end of the buried nanowire segment while covering the epitaxial source region and the gate structure. The epitaxial source region includes a first semiconductor material and dopants of a first conductivity type, while the epitaxial drain region includes a first semiconductor material different from the first semiconductor material and dopants of a second conductivity type opposite the first conductivity type.
    Type: Application
    Filed: May 22, 2017
    Publication date: September 14, 2017
    Applicant: GLOBALFOUNDRIES INC.
    Inventors: Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan, Jeffrey W. Sleight
  • Publication number: 20170236780
    Abstract: An aspect of the disclosure is directed to a method of forming an interconnect for use in an integrated circuit. The method comprises: forming an opening in a dielectric layer on a substrate; filling the opening with a metal such that an overburden outside of the opening is created; subjecting the metal to a microwave energy dose such that atoms from the overburden migrate to within the opening; and planarizing the metal to a top surface of the opening to remove the overburden, thereby forming the interconnect.
    Type: Application
    Filed: April 12, 2017
    Publication date: August 17, 2017
    Inventors: Joyeeta Nag, Shishir K. Ray, Andrew H. Simon, Oleg Gluschenkov, Siddarth A. Krishnan, Michael P. Chudzik
  • Patent number: 9721842
    Abstract: A method of fabricating advanced node field effect transistors using a replacement metal gate process. The method includes dopant a high-k dielectric directly or indirectly by using layers composed of multi-layer thin film stacks, or in other embodiments, by a single blocking layer. By taking advantage of unexpected etch selectivity of the multi-layer stack or the controlled etch process of a single layer stack, etch damage to the high-k may be avoided and work function metal thicknesses can be tightly controlled which in turn allows field effect transistors with low Tinv (inverse of gate capacitance) mismatch.
    Type: Grant
    Filed: March 2, 2016
    Date of Patent: August 1, 2017
    Assignee: International Business Machines Corporation
    Inventors: Takashi Ando, Hemanth Jagannathan, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon, Rekha Rajaram
  • Publication number: 20170207132
    Abstract: A method for fabricating a gate stack of a semiconductor device comprises forming a first dielectric layer over a channel region of the device, depositing a first nitride layer on exposed portions of the first dielectric layer, depositing a scavenging layer on the first nitride layer, forming a capping layer over the scavenging layer, removing portions of the capping layer, the scavenging layer, and the first nitride layer to expose a portion of the first dielectric layer in an n-type field effect transistor (nFET) region of the gate stack, forming a barrier layer over the first dielectric layer and the capping layer, forming a first gate metal layer over the barrier layer, depositing a second nitride layer on the first gate metal layer, and depositing a gate electrode material on the second nitride layer.
    Type: Application
    Filed: January 15, 2016
    Publication date: July 20, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Publication number: 20170207131
    Abstract: A method for fabricating a gate stack of a semiconductor device comprises forming a first dielectric layer over a channel region of the device, forming a first nitride layer over the first dielectric layer, forming a first gate metal layer over the first nitride layer, forming a capping layer over the first gate metal layer, removing portions of the capping layer and the first gate metal layer to expose a portion of the first nitride layer in a p-type field effect transistor (pFET) region of the gate stack, depositing a scavenging layer on the first nitride layer and the capping layer, depositing a second nitride layer on the scavenging layer, and depositing a gate electrode material on the second nitride layer.
    Type: Application
    Filed: January 15, 2016
    Publication date: July 20, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Publication number: 20170207134
    Abstract: The disclosure relates to semiconductor structures and, more particularly, to structures with thinned dielectric material and methods of manufacture. The method includes depositing a high-k dielectric on a substrate. The method further includes depositing a titanium nitride film directly on the high-k while simultaneously etching the high-k dielectric.
    Type: Application
    Filed: March 31, 2017
    Publication date: July 20, 2017
    Inventors: Ruqiang BAO, Takashi ANDO, Aritra DASGUPTA, Kai ZHAO, Unoh KWON, Siddarth A. KRISHNAN
  • Publication number: 20170207219
    Abstract: A method for fabricating a gate stack of a semiconductor device comprises forming a first dielectric layer over a channel region of the device, forming a first nitride layer over the first dielectric layer, depositing a scavenging layer on the first nitride layer, forming a capping layer over the scavenging layer, removing portions of the capping layer and the scavenging layer to expose a portion of the first nitride layer in a n-type field effect transistor (nFET) region of the gate stack, forming a first gate metal layer over the first nitride layer and the capping layer, depositing a second nitride layer on the first gate metal layer, and depositing a gate electrode material on the second nitride layer.
    Type: Application
    Filed: January 3, 2017
    Publication date: July 20, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Patent number: 9704758
    Abstract: An approach to forming a semiconductor structure with improved negative bias temperature instability includes diffusing fluorine atoms into a semiconductor structure by an anneal in a fluorine containing gas. The approach includes removing a pFET work function metal layer from an area above an nFET wherein the area above the nFET includes at least the area over the nFET. Additionally, the approach includes depositing a layer of nFET work function metal on a remaining portion of the pFET work function metal and depositing a gate metal over the nFET work function metal layer. Furthermore, the method includes performing an anneal in a reducing environment followed by a high temperature anneal.
    Type: Grant
    Filed: September 1, 2016
    Date of Patent: July 11, 2017
    Assignee: International Business Machines Corporation
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Patent number: 9691662
    Abstract: Selective deposition of a silicon-germanium surface layer on semiconductor surfaces can be employed to provide two types of channel regions for field effect transistors. Anneal of an adjustment oxide material on a stack of a silicon-based gate dielectric and a high dielectric constant (high-k) gate dielectric can be employed to form an interfacial adjustment oxide layer contacting a subset of channel regions. Oxygen deficiency can be induced in portions of the high-k dielectric layer overlying the interfacial adjustment oxide layer by deposition of a first work function metallic material layer and a capping layer and a subsequent anneal. Oxygen deficiency can be selectively removed by physically exposing portions of the high-k dielectric layer. A second work function metallic material layer and a gate conductor layer can be deposited and planarized to form gate electrodes that provide multiple effective work functions.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: June 27, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Takashi Ando, Min Dai, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon
  • Publication number: 20170179125
    Abstract: A method of making a semiconductor device includes growing an interfacial layer on a substrate; depositing a first titanium nitride (TiN) layer on the interfacial layer; depositing a second TiN layer on the first TiN layer, the first TiN layer and the second TiN layer forming a bilayer work function gate stack of a first transistor; depositing a work function gate stack of a second transistor on the interfacial layer adjacent to the bilayer work function gate stack and on the bilayer work function stack; and depositing a gate electrode material on the work function gate stack of the second transistor.
    Type: Application
    Filed: December 16, 2015
    Publication date: June 22, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Patent number: 9679810
    Abstract: An aspect of the disclosure is directed to a method of forming an interconnect for use in an integrated circuit. The method comprises: forming an opening in a dielectric layer on a substrate; filling the opening with a metal such that an overburden outside of the opening is created; subjecting the metal to a microwave energy dose such that atoms from the overburden migrate to within the opening; and planarizing the metal to a top surface of the opening to remove the overburden, thereby forming the interconnect.
    Type: Grant
    Filed: February 11, 2016
    Date of Patent: June 13, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Joyeeta Nag, Shishir K. Ray, Andrew H. Simon, Oleg Gluschenkov, Siddarth A. Krishnan, Michael P. Chudzik
  • Publication number: 20170148686
    Abstract: An approach to forming a semiconductor structure with improved negative bias temperature instability includes diffusing fluorine atoms into a semiconductor structure by an anneal in a fluorine containing gas. The approach includes removing a pFET work function metal layer from an area above an nFET wherein the area above the nFET includes at least the area over the nFET. Additionally, the approach includes depositing a layer of nFET work function metal on a remaining portion of the pFET work function metal and depositing a gate metal over the nFET work function metal layer. Furthermore, the method includes performing an anneal in a reducing environment followed by a high temperature anneal.
    Type: Application
    Filed: September 1, 2016
    Publication date: May 25, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Patent number: 9660027
    Abstract: After forming a buried nanowire segment surrounded by a gate structure located on a substrate, an epitaxial source region is grown on a first end of the buried nanowire segment while covering a second end of the buried nanowire segment and the gate structure followed by growing an epitaxial drain region on the second end of the buried nanowire segment while covering the epitaxial source region and the gate structure. The epitaxial source region includes a first semiconductor material and dopants of a first conductivity type, while the epitaxial drain region includes a first semiconductor material different from the first semiconductor material and dopants of a second conductivity type opposite the first conductivity type.
    Type: Grant
    Filed: October 20, 2015
    Date of Patent: May 23, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan, Jeffrey W. Sleight
  • Publication number: 20170133278
    Abstract: Multiple gate stack portions are formed in a gate cavity by direct metal gate patterning to provide FinFETs having different threshold voltages. The different threshold voltages are obtained by selectively incorporating metal layers with different work functions in different gate stack portions.
    Type: Application
    Filed: January 23, 2017
    Publication date: May 11, 2017
    Applicant: GLOBALFOUNDRIES INC.
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Keith Kwong Hon Wong
  • Publication number: 20170110376
    Abstract: The disclosure relates to semiconductor structures and, more particularly, to structures with thinned dielectric material and methods of manufacture. The method includes depositing a high-k dielectric on a substrate. The method further includes depositing a titanium nitride film directly on the high-k while simultaneously etching the high-k dielectric.
    Type: Application
    Filed: October 14, 2015
    Publication date: April 20, 2017
    Inventors: Ruqiang BAO, Takashi ANDO, Aritra DASGUPTA, Kai ZHAO, Unoh KWON, Siddarth A. KRISHNAN