Patents by Inventor Siddarth Krishnan

Siddarth 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).

  • Publication number: 20170110375
    Abstract: A first aspect of the invention provides for a method including: forming an interfacial layer in a first opening in a pFET region and a second opening in an nFET region, each opening being in a dielectric layer in the pFET region and the nFET region; forming a high-k layer over the interfacial layer in each of the first and second openings; forming a wetting layer over the high-k layer in each of the first and second openings; forming a first metal layer in each of the first and second openings, the first metal layer including tungsten; and forming a first gate electrode layer over the first metal layer to substantially fill each of the first and second openings, thereby forming a first replacement gate stack over the pFET region and a second replacement gate stack over the nFET region.
    Type: Application
    Filed: October 14, 2015
    Publication date: April 20, 2017
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • 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
  • Patent number: 9627508
    Abstract: A semiconductor structure includes a substrate and an intrinsic replacement channel. A tunneling field effect transistor (TFET) fin may be formed by the intrinsic replacement channel, a p-fin and an n-fin formed upon the substrate. The p-fin may serve as the source of the TFET and the n-fin may serve as the drain of the TFET. The replacement channel may be formed in place of a sacrificial channel of a diode fin that includes the p-fin, the n-fin, and the sacrificial channel at the p-fin and n-fin junction.
    Type: Grant
    Filed: April 14, 2015
    Date of Patent: April 18, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Michael P. Chudzik, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan, Jeffrey W. Sleight
  • Patent number: 9583400
    Abstract: A method for fabricating a gate stack of a semiconductor device comprising forming a first dielectric layer over a channel region of the device, forming a barrier layer over the first dielectric layer, forming a first gate metal layer over the barrier layer, forming a capping layer over the first gate metal layer, removing portions of the barrier layer, the first gate metal layer, and the capping layer to expose a portion of the first dielectric layer in a p-type field effect transistor (pFET) region of the gate stack, depositing a first nitride layer on exposed portions of the capping layer and the first dielectric layer, depositing a scavenging layer on the first nitride 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: February 28, 2017
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Patent number: 9576958
    Abstract: An approach to forming a semiconductor structure with improved negative bias temperature instability includes forming an interfacial layer on a semiconductor substrate with an nFET and a pFET. The semiconductor structure includes a gate dielectric layer on the interfacial layer and a pFET work function metal layer on a portion of the gate dielectric layer over an area above the pFET. The semiconductor structure includes a nFET work function metal layer on a portion of the gate dielectric layer over an area above the nFET and on the pFET work function metal layer in the area above the pFET. The semiconductor structure includes a gate electrode metal on the nFET work function metal layer where a plurality of fluorine atoms and a plurality of reducing gas atoms are incorporated into at least a portion of the interfacial layer, the gate layer, and a portion of the nFET work function metal.
    Type: Grant
    Filed: June 9, 2016
    Date of Patent: February 21, 2017
    Assignee: International Business Machines Corporation
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Publication number: 20170047255
    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: Application
    Filed: October 31, 2016
    Publication date: February 16, 2017
    Inventors: Takashi Ando, Min Dai, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon
  • Patent number: 9559016
    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 15, 2016
    Date of Patent: January 31, 2017
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan
  • Publication number: 20170025315
    Abstract: A method for forming a replacement metal gate structure sharing a single work function metal for both the N-FET and the P-FET gates. The method oppositely dopes a high-k material of the N-FET and P-FET gate, respectively, using a single lithography step. The doping allows use of a single work function metal which in turn provides more space in the metal gate opening so that a bulk fill material may occupy more volume of the opening resulting in a lower resistance gate.
    Type: Application
    Filed: October 4, 2016
    Publication date: January 26, 2017
    Inventors: Takashi Ando, Balaji Kannan, Siddarth Krishnan, Unoh Kwon, Shahab Siddiqui
  • Patent number: 9553092
    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: Grant
    Filed: June 12, 2015
    Date of Patent: January 24, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Keith Kwong Hon Wong
  • Patent number: 9548381
    Abstract: A heterojunction tunnel field effect transistor (TFET) has a channel region that includes a first portion of a nanowire, a source region and a drain region that respectively include a second portion and a third portion of a nanowire, and a gate that surrounds the channel region, where the first portion of the nanowire comprises an intrinsic, epitaxial III-V semiconductor. The TFET can be made by selectively etching the epitaxial underlayer to define a tethered (suspended) nanowire that forms a channel region of the device. Source and drain regions can be formed from regrown p-type and n-type epitaxial layers.
    Type: Grant
    Filed: December 14, 2015
    Date of Patent: January 17, 2017
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan, Jeffrey W. Sleight
  • Publication number: 20160365347
    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: June 12, 2015
    Publication date: December 15, 2016
    Inventors: Ruqiang Bao, Siddarth A. Krishnan, Unoh Kwon, Keith Kwong Hon Wong
  • Patent number: 9515164
    Abstract: A method for forming a replacement metal gate structure sharing a single work function metal for both the N-FET and the P-FET gates. The method oppositely dopes a high-k material of the N-FET and P-FET gate, respectively, using a single lithography step. The doping allows use of a single work function metal which in turn provides more space in the metal gate opening so that a bulk fill material may occupy more volume of the opening resulting in a lower resistance gate.
    Type: Grant
    Filed: March 6, 2014
    Date of Patent: December 6, 2016
    Assignee: International Business Machines Corporation
    Inventors: Takashi Ando, Balaji Kannan, Siddarth Krishnan, Unoh Kwon, Shahab Siddiqui
  • Publication number: 20160351452
    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 Tiny (inverse of gate capacitance) mismatch.
    Type: Application
    Filed: August 10, 2016
    Publication date: December 1, 2016
    Inventors: Takashi Ando, Hemanth Jagannathan, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon, Rekha Rajaram
  • Patent number: 9502307
    Abstract: An approach to forming a semiconductor structure with improved negative bias temperature instability includes forming an interfacial layer on a semiconductor substrate with an nFET and a pFET. The approach includes depositing a gate dielectric layer on the interfacial layer. Additionally, the approach includes an nFET work function metal layer deposited on the interfacial layer. Additionally, the approach includes removing the nFET work function metal from an area above the pFET and depositing a pFET work function metal layer on a portion of the exposed gate dielectric layer where the portion of the exposed gate dielectric layer is over the pFET. Furthermore, the approach includes depositing a gate metal on the pFET work function metal layer where the gate metal is deposited in an environment with a fluorine containing gas followed by an anneal in a reducing environment.
    Type: Grant
    Filed: November 20, 2015
    Date of Patent: November 22, 2016
    Assignee: International Business Machines Corporation
    Inventors: Ruqiang Bao, Siddarth A. Krishnan
  • Patent number: 9484427
    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: July 1, 2014
    Date of Patent: November 1, 2016
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Takashi Ando, Min Dai, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon
  • Publication number: 20160308025
    Abstract: A semiconductor structure includes a substrate and an intrinsic replacement channel. A tunneling field effect transistor (TFET) fin may be formed by the intrinsic replacement channel, a p-fin and an n-fin formed upon the substrate. The p-fin may serve as the source of the TFET and the n-fin may serve as the drain of the TFET. The replacement channel may be formed in place of a sacrificial channel of a diode fin that includes the p-fin, the n-fin, and the sacrificial channel at the p-fin and n-fin junction.
    Type: Application
    Filed: April 14, 2015
    Publication date: October 20, 2016
    Inventors: Michael P. Chudzik, Siddarth A. Krishnan, Unoh Kwon, Vijay Narayanan, Jeffrey W. Sleight
  • Patent number: 9472419
    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: October 22, 2015
    Date of Patent: October 18, 2016
    Assignee: International Business Machines Corporation
    Inventors: Takashi Ando, Hemanth Jagannathan, Balaji Kannan, Siddarth A. Krishnan, Unoh Kwon, Rekha Rajaram
  • Publication number: 20160240478
    Abstract: A method for forming a precision resistor or an e-fuse structure where tungsten silicon is used. The tungsten silicon layer is modified by implanting nitrogen into the structure.
    Type: Application
    Filed: February 16, 2015
    Publication date: August 18, 2016
    Inventors: Domingo A. Ferrer, Kriteshwar K. Kohli, Siddarth A. Krishnan, Joseph F. Shepard, JR., Keith Kwong Hon Wong
  • Patent number: 9412658
    Abstract: In-situ melting and crystallization of sealed cooper wires can be performed by means of laser annealing for a duration of nanoseconds. The intensity of the laser irradiation is selected such that molten copper wets interconnect interfaces, thereby forming an interfacial bonding arrangement that increases specular scattering of electrons. Nanosecond-scale temperature quenching preserves the formed interfacial bonding. At the same time, the fast crystallization process of sealed copper interconnects results in large copper grains, typically larger than 80 nm in lateral dimensions, on average. A typical duration of the annealing process is from about 10's to about 100's of nanoseconds. There is no degradation to interlayer low-k dielectric material despite the high anneal temperature due to ultra short duration that prevents collective motion of atoms within the dielectric material.
    Type: Grant
    Filed: September 19, 2014
    Date of Patent: August 9, 2016
    Assignees: INTERNATIONAL BUSINESS MACHINES CORPORATION, GLOBALFOUNDRIES INC.
    Inventors: Oleg Gluschenkov, Siddarth A. Krishnan, Joyeeta Nag, Andrew H. Simon, Shishir Ray
  • Patent number: 9397177
    Abstract: A method of forming a semiconductor device includes forming first and second semiconductor structures on a semiconductor substrate. The first semiconductor structure includes a first gate channel region having a first gate length, and the second semiconductor structure including a second gate channel region having a second gate length that is greater than the first gate length. The method further includes depositing a work function metal layer in each of a first gate void formed at the first gate channel region and a second gate void formed at the second gate channel region. The method further includes depositing a semiconductor masking layer on the work function metal layer, and simultaneously etching the silicon masking layer located at the first and second gate channel regions to re-expose the first and second gate voids. A low-resistive metal is deposited in the first and second gate voids to form low-resistive metal gate stacks.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: July 19, 2016
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Michael P. Chudzik, Siddarth A. Krishnan, Unoh Kwon