Patents by Inventor Chandrasekharan Kothandaraman

Chandrasekharan Kothandaraman 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: 20210151503
    Abstract: A semiconductor structure and fabrication method of forming a semiconductor structure. The structure is a MRAM element having a first conductive electrode embedded in a first interconnect dielectric material layer upon which a multi-layered magnetic tunnel junction (MTJ) memory element is formed in a magnetoresistive random access memory (MRAM) device area. The first conductive electrode includes a first end having a top surface of a first surface area and a second end having a bottom surface of a second surface area, the first surface area being smaller than the second surface area. The second end of the bottom electrode includes a barrier liner material including a metal fill material, and the first end of the bottom electrode is a pillar structure formed as a result of an etchback process in which the metal barrier liner is recessed relative to the metal fill material.
    Type: Application
    Filed: December 29, 2020
    Publication date: May 20, 2021
    Inventors: Pouya Hashemi, Bruce B.` Doris, Chandrasekharan Kothandaraman, Nathan P. Marchack
  • Patent number: 10984948
    Abstract: A method for forming an inductor device. The method comprises forming a trench within a central core region of a conductive coil formed within a dielectric material. The method further comprises forming a composite region within the trench. The composite region including a polymer matrix having a plurality of particles with magnetic properties dispersed therein with the central core region to reduce eddy current loss and increase energy storage.
    Type: Grant
    Filed: November 2, 2017
    Date of Patent: April 20, 2021
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Chandrasekharan Kothandaraman, Eugene J. O'Sullivan, Naigang Wang
  • Patent number: 10957738
    Abstract: A semiconductor structure and fabrication method of forming a semiconductor structure. The structure is a MRAM element having a first conductive electrode embedded in a first interconnect dielectric material layer upon which a multi-layered magnetic tunnel junction (MTJ) memory element is formed in a magnetoresistive random access memory (MRAM) device area. The first conductive electrode includes a first end having a top surface of a first surface area and a second end having a bottom surface of a second surface area, the first surface area being smaller than the second surface area. The second end of the bottom electrode includes a barrier liner material including a metal fill material, and the first end of the bottom electrode is a pillar structure formed as a result of an etchback process in which the metal barrier liner is recessed relative to the metal fill material.
    Type: Grant
    Filed: April 3, 2019
    Date of Patent: March 23, 2021
    Assignee: International Business Machines Corporation
    Inventors: Pouya Hashemi, Bruce B. Doris, Chandrasekharan Kothandaraman, Nathan P. Marchack
  • Patent number: 10942072
    Abstract: A sub-micrometer pressure sensor including a multilayered magnetic tunnel junction (MTJ) pillar containing a magnetostrictive material layer above or below a magnetic free layer of the multilayered MTJ pillar is provided. Advanced patterning allows for scaling of the multilayered MTJ pillar down to 25 nm or below which enables the formation of a large array of extremely high resolution pressure sensors. By varying the thickness of the magnetostrictive material layer, the sensitivity of the pressure sensor can be fine tuned. Unique magnetostrictive materials in the multilayered MTJ pillar will alter the device current with the input of external pressure. Furthermore, unique arrays with much smaller critical elements can be organized in differential sensing arrangements of the multilayered MTJ pillar with pressure sensing capability that can outperform current piezoelectric based pressure sensing arrays.
    Type: Grant
    Filed: November 20, 2018
    Date of Patent: March 9, 2021
    Assignee: International Business Machines Corporation
    Inventors: Chandrasekharan Kothandaraman, Eric Raymond Evarts, Virat Vasav Mehta, Pouya Hashemi, Alexander Reznicek
  • Patent number: 10937828
    Abstract: Fabricating a magnetoresistive random access memory (MRAM) device includes receiving a wafer structure having a first inter-layer dielectric (ILD) layer and a metal material disposed within the first ILD layer. A second ILD layer is deposited upon a top surface of the first ILD layer and the metal material. A trench is formed within the second ILD layer extending to the top surface of the metal material. A plurality of magnetic stack layers of a magnetic stack and an electrode layer are deposited within the trench. Portions of each of the magnetic stack layers of the magnetic stack and the electrode layer are removed to form a v-shaped magnetic tunnel junction (MTJ) in contact with the metal material.
    Type: Grant
    Filed: October 11, 2018
    Date of Patent: March 2, 2021
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Pouya Hashemi, Matthias Georg Gottwald, Alexander Reznicek, Chandrasekharan Kothandaraman
  • Patent number: 10840441
    Abstract: Techniques for MRAM patterning using a diamond-like carbon hardmask are provided. In one aspect, a method of forming an MRAM device includes: forming an MRAM stack on a substrate; depositing a metal hardmask layer on the MRAM stack; depositing a diamond-like carbon layer on the metal hardmask layer; forming a patterned resist on the diamond-like carbon layer; patterning the diamond-like carbon layer using the patterned resist to form a diamond-like carbon pillar; patterning the metal hardmask layer using the diamond-like carbon pillar to form a patterned metal hardmask; and patterning the MRAM stack into an MRAM pillar using the patterned metal hardmask to form the MRAM device. An MRAM device is also provided.
    Type: Grant
    Filed: September 14, 2018
    Date of Patent: November 17, 2020
    Assignee: International Business Machines Corporation
    Inventors: Anthony Annunziata, Nathan P. Marchack, Eugene O'Sullivan, Chandrasekharan Kothandaraman
  • Publication number: 20200326911
    Abstract: A true random number generator (TRNG) device having a magnetic tunnel junction (MTJ) structure coupled to a domain wall wire. The MTJ structure is formed of a free layer (FL) and a reference layer (RL) that sandwiches a tunnel barrier layer. The free layer has anisotropy energy sufficiently low to provide stochastic fluctuation in the orientation of the magnetic state of the free layer via thermal energy. The domain wall wire is coupled to the MTJ structure. The domain wall wire has a domain wall. Movement of the domain wall tunes a probability distribution of the fluctuation in the orientation of the magnetic state of the free layer. The domain wall can be moved by application of a suitable current through the wire to tune the probability distribution of 1's and 0's generated by a readout circuit the TRNG device.
    Type: Application
    Filed: April 15, 2019
    Publication date: October 15, 2020
    Inventors: Rasit O. Topaloglu, Jonathan Z. Sun, Matthias G. Gottwald, Chandrasekharan Kothandaraman
  • Publication number: 20200321394
    Abstract: A semiconductor structure and fabrication method of forming a semiconductor structure. The structure is a MRAM element having a first conductive electrode embedded in a first interconnect dielectric material layer upon which a multi-layered magnetic tunnel junction (MTJ) memory element is formed in a magnetoresistive random access memory (MRAM) device area. The first conductive electrode includes a first end having a top surface of a first surface area and a second end having a bottom surface of a second surface area, the first surface area being smaller than the second surface area. The second end of the bottom electrode includes a barrier liner material including a metal fill material, and the first end of the bottom electrode is a pillar structure formed as a result of an etchback process in which the metal barrier liner is recessed relative to the metal fill material.
    Type: Application
    Filed: April 3, 2019
    Publication date: October 8, 2020
    Inventors: Pouya Hashemi, Bruce B. Doris, Chandrasekharan Kothandaraman, Nathan P. Marchack
  • Publication number: 20200303386
    Abstract: A magnetic tunnel junction (MTJ) containing device and methods of constructing the MTJ containing device are described. In an example, the MTJ containing device may be a memory element including a bottom electrode structure, a MTJ pillar, and a top electrode structure located on the MTJ pillar. The MTJ pillar has a non-circular lateral cross section, where the MTJ pillar has a bottommost portion forming an interface with an uppermost portion of the bottom electrode structure. The MTJ pillar has a lateral perimeter-to-area ratio that defines a breakdown voltage of the MTJ pillar.
    Type: Application
    Filed: March 21, 2019
    Publication date: September 24, 2020
    Inventors: Chandrasekharan Kothandaraman, Babar Khan, Nathan P. Marchack, Bruce B. Doris
  • Publication number: 20200303452
    Abstract: A memory element and methods of constructing the memory element are described. The memory element may include a bottom electrode structure having an uppermost portion of a first dimension. The memory element may further include a MTJ pillar having a bottommost portion forming an interface with the uppermost portion of the bottom electrode structure. The bottommost portion of the MTJ pillar may have a second dimension that is less than the first dimension. The memory element may further include oxidized metal particles located on an outermost sidewall of the MTJ pillar. The memory element may further include a top electrode structure located in the MTJ pillar.
    Type: Application
    Filed: March 21, 2019
    Publication date: September 24, 2020
    Inventors: Dimitri Houssameddine, Chandrasekharan Kothandaraman, Bruce B. Doris
  • Patent number: 10784268
    Abstract: A magnetic tunnel junction (MTJ) containing device and methods of constructing the MTJ containing device are described. In an example, the MTJ containing device may be a memory element including a bottom electrode structure, a MTJ pillar, and a top electrode structure located on the MTJ pillar. The MTJ pillar has a non-circular lateral cross section, where the MTJ pillar has a bottommost portion forming an interface with an uppermost portion of the bottom electrode structure. The MTJ pillar has a lateral perimeter-to-area ratio that defines a breakdown voltage of the MTJ pillar.
    Type: Grant
    Filed: March 21, 2019
    Date of Patent: September 22, 2020
    Assignee: International Business Machines Corporation
    Inventors: Chandrasekharan Kothandaraman, Babar Khan, Nathan P. Marchack, Bruce B. Doris
  • Publication number: 20200279058
    Abstract: A memory system in an integrated circuit and a method of operation. The system includes multiple magnetic tunnel junction (MTJ) structures, each MTJ structure storing a logic value according to a resistive state. A selection switch device associated with a respective MTJ structure is activated to select one of the multiple MTJ structures at a time. An output circuit is configured to sense the resistive state of a selected MTJ structure, the output circuit having a selectable input reference resistance value according to a selected first reference resistance or a second reference resistance value, and outputting a first logic value of the selected MTJ structure responsive to a resistive state of the MTJ structure and a selected first resistance reference value, or alternately outputting a second logic value of the selected MTJ structure responsive to the resistive state of the MTJ structure and a selected second resistance reference value.
    Type: Application
    Filed: February 28, 2019
    Publication date: September 3, 2020
    Inventors: Chandrasekharan Kothandaraman, Dimitri Houssameddine, Bruce B. Doris
  • Patent number: 10741327
    Abstract: An inductor device includes a conductive coil formed within a dielectric material and having a central core area within the coil. Particles are dispersed within the central core region to reduce eddy current loss and increase energy storage. The particles include magnetic properties.
    Type: Grant
    Filed: January 30, 2017
    Date of Patent: August 11, 2020
    Assignee: International Business Machines Corporation
    Inventors: Chandrasekharan Kothandaraman, Eugene J. O'Sullivan, Naigang Wang
  • Patent number: 10741752
    Abstract: Methods of forming the MRAM generally include forming an array of MTJ having sub-lithographic dimensions. The array can be formed by providing a substrate including a MTJ material stack including a reference ferromagnetic layer, a tunnel barrier layer, and a free ferromagnetic layer on an opposite side of the tunnel barrier layer. A hardmask layer is deposited onto the MTJ material stack. A first sidewall spacer is formed on the hardmask layer in a first direction. A second sidewall spacer is formed over the first sidewall in a second direction, wherein the first direction is orthogonal to the second direction. The second sidewall spacer intersects the first sidewall spacer. The first sidewall spacer is processed using the second sidewall spacer as mask to form a pattern of oxide pillars having sub-lithographic dimensions. The pattern of oxide pillars are transferred into the MTJ stack to form the array.
    Type: Grant
    Filed: January 6, 2020
    Date of Patent: August 11, 2020
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Anthony J. Annunziata, Babar A. Khan, Chandrasekharan Kothandaraman, John R. Sporre
  • Publication number: 20200243750
    Abstract: A magnetic tunnel junction (MTJ) containing device is provided in which a bottom electrode having a small CD is formed and is located laterally adjacent to diamond like carbon (DLC). DLC replaces a material stack of, from bottom to top, a silicon nitride layer and an organic planarization layer (OPL) which is typically used in providing a conductive structure having a reduced CD. DLC provides a higher etch resistance to IBE than silicon nitride, but DLC can be patterned using conventional etchants. The use of DLC thus reduces the number of processing steps for providing a reduced CD bottom electrode, and also provides a more robust solution to the issue of punch through to an underlying conductive material layer.
    Type: Application
    Filed: January 30, 2019
    Publication date: July 30, 2020
    Inventors: Nathan P. Marchack, Bruce B. Doris, Chandrasekharan Kothandaraman
  • Patent number: 10727398
    Abstract: A magnetic tunnel junction (MTJ) containing device is provided in which a bottom electrode having a small CD is formed and is located laterally adjacent to diamond like carbon (DLC). DLC replaces a material stack of, from bottom to top, a silicon nitride layer and an organic planarization layer (OPL) which is typically used in providing a conductive structure having a reduced CD. DLC provides a higher etch resistance to IBE than silicon nitride, but DLC can be patterned using conventional etchants. The use of DLC thus reduces the number of processing steps for providing a reduced CD bottom electrode, and also provides a more robust solution to the issue of punch through to an underlying conductive material layer.
    Type: Grant
    Filed: January 30, 2019
    Date of Patent: July 28, 2020
    Assignee: International Business Machines Corporation
    Inventors: Nathan P. Marchack, Bruce B. Doris, Chandrasekharan Kothandaraman
  • Publication number: 20200217735
    Abstract: A sub-micrometer pressure sensor is provided that includes a multilayered magnetic tunnel junction (MTJ) pillar that contains a non-magnetic metallic spacer separating a first magnetic free layer from a second magnetic free layer. The presence of the non-magnetic metallic spacer in the multilayered MTJ pillar improves the sensitivity without compromising area, and makes the pressure sensor binary (either “on” or “off”) with little or no drift, and sensitivity change over time. Moreover, the resistivity switch in such a pressure sensor is instantly and a low error rate is observed.
    Type: Application
    Filed: January 7, 2019
    Publication date: July 9, 2020
    Inventors: Virat Vasav Mehta, Alexander Reznicek, Chandrasekharan Kothandaraman, Eric Raymond Evarts, Pouya Hashemi
  • Patent number: 10700263
    Abstract: A semiconductor device and a method for fabricating the same. The semiconductor device includes a substrate. At least one trench line is formed within the substrate. A pad layer is formed in contact with the at least one trench line. A seed layer is formed on and in contact with the pad layer. The seed layer has a Root Mean Square surface roughness equal to or less than 3 Angstroms. A magnetic tunnel junction stack is formed on and in contact with the seed layer. The method includes forming a seed layer on and in contact with a semiconductor structure. The seed layer is annealed and then planarized. A magnetic tunnel junction stack is formed on and in contact with the seed layer after the seed layer has been planarized.
    Type: Grant
    Filed: February 1, 2018
    Date of Patent: June 30, 2020
    Assignee: International Business Machines Corporation
    Inventors: Anthony J. Annunziata, Chandrasekharan Kothandaraman, Janusz J. Nowak, Eugene J. O'Sullivan
  • Publication number: 20200158582
    Abstract: A sub-micrometer pressure sensor including a multilayered magnetic tunnel junction (MTJ) pillar containing a magnetostrictive material layer above or below a magnetic free layer of the multilayered MTJ pillar is provided. Advanced patterning allows for scaling of the multilayered MTJ pillar down to 25 nm or below which enables the formation of a large array of extremely high resolution pressure sensors. By varying the thickness of the magnetostrictive material layer, the sensitivity of the pressure sensor can be fine tuned. Unique magnetostrictive materials in the multilayered MTJ pillar will alter the device current with the input of external pressure. Furthermore, unique arrays with much smaller critical elements can be organized in differential sensing arrangements of the multilayered MTJ pillar with pressure sensing capability that can outperform current piezoelectric based pressure sensing arrays.
    Type: Application
    Filed: November 20, 2018
    Publication date: May 21, 2020
    Inventors: Chandrasekharan Kothandaraman, Eric Raymond Evarts, Virat Vasav Mehta, Pouya Hashemi, Alexander Reznicek
  • Publication number: 20200144495
    Abstract: Methods of forming the MRAM generally include forming an array of MTJ having sub-lithographic dimensions. The array can be formed by providing a substrate including a MTJ material stack including a reference ferromagnetic layer, a tunnel barrier layer, and a free ferromagnetic layer on an opposite side of the tunnel barrier layer. A hardmask layer is deposited onto the MTJ material stack. A first sidewall spacer is formed on the hardmask layer in a first direction. A second sidewall spacer is formed over the first sidewall in a second direction, wherein the first direction is orthogonal to the second direction. The second sidewall spacer intersects the first sidewall spacer. The first sidewall spacer is processed using the second sidewall spacer as mask to form a pattern of oxide pillars having sub-lithographic dimensions. The pattern of oxide pillars are transferred into the MTJ stack to form the array.
    Type: Application
    Filed: January 6, 2020
    Publication date: May 7, 2020
    Inventors: Anthony J. Annunziata, Babar A. Khan, Chandrasekharan Kothandaraman, John R. Sporre