Patents by Inventor Ramachandra Divakaruni

Ramachandra Divakaruni 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: 20170005113
    Abstract: A method for forming CMOS devices includes masking a first portion of a tensile-strained silicon layer of a SOI substrate, doping a second portion of the layer outside the first portion and growing an undoped silicon layer on the doped portion and the first portion. The undoped silicon layer becomes tensile-strained. Strain in the undoped silicon layer over the doped portion is relaxed by converting the doped portion to a porous silicon to form a relaxed silicon layer. The porous silicon is converted to an oxide. A SiGe layer is grown and oxidized to convert the relaxed silicon layer to a compressed SiGe layer. Fins are etched in the first portion from the tensile-strained silicon layer and the undoped silicon layer and in the second portion from the compressed SiGe layer.
    Type: Application
    Filed: July 2, 2015
    Publication date: January 5, 2017
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Jeehwan Kim, Juntao Li, Devendra K. Sadana
  • Patent number: 9537011
    Abstract: One embodiment provides a method comprising etching a fin of a fin-shaped field effect transistor (FinFET) to form a reduced fin, and laterally etching the reduced fin to form a fin channel including a first fin channel sidewall and a second fin channel sidewall opposing the first fin channel sidewall. The method further comprises forming a first thin dielectric tunnel and a second thin dielectric tunnel on the first fin channel sidewall and the second fin channel sidewall, respectively. Each thin dielectric tunnel prevents lateral epitaxial crystal growth on the fin channel. The method further comprises etching an insulator layer disposed between the fin channel and a substrate of the FinFET to expose portions of a substrate surface of the substrate. A source epitaxy and a drain epitaxy are formed from vertical epitaxial crystal growth on the exposed portions of the substrate surface after epitaxial deposition.
    Type: Grant
    Filed: December 14, 2015
    Date of Patent: January 3, 2017
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Johnathan E. Faltermeier, Edward J. Nowak, Kern Rim
  • Patent number: 9524986
    Abstract: The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a high-mobility fin field effect transistor (finFET) fin in a silicon semiconductor on insulator (SOI) substrate by trapping crystalline lattice dislocations that occur during epitaxial growth in a recess formed in a semiconductor layer. The crystalline lattice dislocations may remain trapped below a thin isolation layer, thereby reducing device thickness and the need for high-aspect ratio etching and fin formation.
    Type: Grant
    Filed: June 26, 2014
    Date of Patent: December 20, 2016
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Michael P. Chudzik, Ramachandra Divakaruni, Judson R. Holt, Arvind Kumar, Unoh Kwon
  • Publication number: 20160359038
    Abstract: After formation of gate structures over semiconductor fins and prior to formation of raised active regions, a directional ion beam is employed to form a dielectric material portion on end walls of semiconductor fins that are perpendicular to the lengthwise direction of the semiconductor fins. The angle of the directional ion beam is selected to be with a vertical plane including the lengthwise direction of the semiconductor fins, thereby avoiding formation of the dielectric material portion on lengthwise sidewalls of the semiconductor fins. Selective epitaxy of semiconductor material is performed to grow raised active regions from sidewall surfaces of the semiconductor fins. Optionally, horizontal portions of the dielectric material portion may be removed prior to the selective epitaxy process. Further, the dielectric material portion may optionally be removed after the selective epitaxy process.
    Type: Application
    Filed: August 17, 2016
    Publication date: December 8, 2016
    Applicant: GLOBALFOUNDRIES INC.
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Carl J. Radens
  • Patent number: 9515140
    Abstract: A method that includes forming a pattern of strained material and relaxed material on a substrate; forming a strained device in the strained material; and forming a non-strained device in the relaxed material is disclosed. In one embodiment, the strained material is silicon (Si) in either a tensile or compressive state, and the relaxed material is Si in a normal state. A buffer layer of silicon germanium (SiGe), silicon carbon (SiC), or similar material is formed on the substrate and has a lattice constant/structure mis-match with the substrate. A relaxed layer of SiGe, SiC, or similar material is formed on the buffer layer and places the strained material in the tensile or compressive state. In another embodiment, carbon-doped silicon or germanium-doped silicon is used to form the strained material. The structure includes a multi-layered substrate having strained and non-strained materials patterned thereon.
    Type: Grant
    Filed: January 16, 2008
    Date of Patent: December 6, 2016
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Kangguo Cheng, Ramachandra Divakaruni
  • Patent number: 9496258
    Abstract: A bulk semiconductor substrate including a first semiconductor material is provided. A well trapping layer including a second semiconductor material and a dopant is formed on a top surface of the bulk semiconductor substrate. The combination of the second semiconductor material and the dopant within the well trapping layer is selected such that diffusion of the dopant is limited within the well trapping layer. A device semiconductor material layer including a third semiconductor material can be epitaxially grown on the top surface of the well trapping layer. The device semiconductor material layer, the well trapping layer, and an upper portion of the bulk semiconductor substrate are patterned to form at least one semiconductor fin. Semiconductor devices formed in each semiconductor fin can be electrically isolated from the bulk semiconductor substrate by the remaining portions of the well trapping layer.
    Type: Grant
    Filed: October 9, 2014
    Date of Patent: November 15, 2016
    Assignee: International Business Machines Corporation
    Inventors: Henry K. Utomo, Kangguo Cheng, Ramachandra Divakaruni, Ravikumar Ramachandran, Huiling Shang, Reinaldo A. Vega
  • Patent number: 9484347
    Abstract: A method for forming a complementary metal oxide semiconductor (CMOS) device includes growing a SiGe layer on a Si semiconductor layer, and etching fins through the SiGe layer and the Si semiconductor layer down to a buried dielectric layer. Spacers are formed on sidewalls of the fins, and a dielectric material is formed on top of the buried dielectric layer between the fins. The SiGe layer is replaced with a dielectric cap for an n-type device to form a Si fin. The Si semiconductor layer is converted to a SiGe fin for a p-type device by oxidizing the SiGe layer to condense Ge. The dielectric material is recessed to below the spacers, and the dielectric cap and the spacers are removed to expose the Si fin and the SiGe fin.
    Type: Grant
    Filed: December 15, 2015
    Date of Patent: November 1, 2016
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Jeehwan Kim
  • Patent number: 9484267
    Abstract: A semiconductor device comprises first stack of nanowires arranged on a substrate comprises a first nanowire and a second nanowire, the second nanowire is arranged substantially co-planar in a first plane with the first nanowire the first nanowire and the second nanowire arranged substantially parallel with the substrate, a second stack of nanowires comprises a third nanowire and a fourth nanowire, the third nanowire and the fourth nanowire arranged substantially co-planar in the first plane with the first nanowire, and the first nanowire and the second nanowire comprises a first semiconductor material and the third nanowire and the fourth nanowire comprises a second semiconductor material, the first semiconductor material dissimilar from the second semiconductor material.
    Type: Grant
    Filed: February 4, 2016
    Date of Patent: November 1, 2016
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Juntao Li
  • Patent number: 9472402
    Abstract: Increased protection of areas of a chip are provided by both a mask structure of increased robustness in regard to semiconductor manufacturing processes or which can be removed with increased selectivity and controllability in regard to underlying materials, or both. Mask structures are provided which exhibit an interface of a chemical reaction, grain or material type which can be exploited to enhance either or both types of protection. Structures of such masks include TERA material which can be converted or hydrated and selectively etched using a mixture of hydrogen fluoride and a hygroscopic acid or organic solvent, and two layer structures of similar or dissimilar materials.
    Type: Grant
    Filed: September 16, 2014
    Date of Patent: October 18, 2016
    Assignee: GLOBALFOUNDRIES Inc.
    Inventors: Deok-kee Kim, Kenneth T. Settlemyer, Jr., Kangguo Cheng, Ramachandra Divakaruni, Carl J. Radens, Dirk Pfeiffer, Timothy J. Dalton, Katherina E. Babich, Arpan P. Mohorowala, Harald Okorn-Schmidt
  • Publication number: 20160293704
    Abstract: A semiconductor structure includes a material stack located on a surface of a semiconductor substrate. The material stack includes, from bottom to top, a silicon germanium alloy portion that is substantially relaxed and defect-free and a semiconductor material pillar that is defect-free. A dielectric material structure surrounds sidewalls of the material stack and is present on exposed portions of the semiconductor substrate.
    Type: Application
    Filed: March 30, 2015
    Publication date: October 6, 2016
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Hong He, Juntao Li
  • Patent number: 9455314
    Abstract: A semiconductor structure is provided that includes at least one punch-through stop base structure having concave outermost sidewalls and located on a semiconductor surface of a semiconductor substrate. The structure further includes a pair of semiconductor fins extending upwards from a topmost surface of the at least one punch through stop base structure. The structure even further includes a trench isolation structure located laterally adjacent each of the concave outermost sidewalls of the at least one punch-through stop base structure, wherein a dopant source dielectric material liner is located on each of the concave outermost sidewalls of the at least one punch-through stop base structure and is present between the at least one punch-through stop base structure and the trench isolation structure.
    Type: Grant
    Filed: February 5, 2016
    Date of Patent: September 27, 2016
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Juntao Li
  • Patent number: 9431523
    Abstract: After formation of gate structures over semiconductor fins and prior to formation of raised active regions, a directional ion beam is employed to form a dielectric material portion on end walls of semiconductor fins that are perpendicular to the lengthwise direction of the semiconductor fins. The angle of the directional ion beam is selected to be with a vertical plane including the lengthwise direction of the semiconductor fins, thereby avoiding formation of the dielectric material portion on lengthwise sidewalls of the semiconductor fins. Selective epitaxy of semiconductor material is performed to grow raised active regions from sidewall surfaces of the semiconductor fins. Optionally, horizontal portions of the dielectric material portion may be removed prior to the selective epitaxy process. Further, the dielectric material portion may optionally be removed after the selective epitaxy process.
    Type: Grant
    Filed: January 16, 2014
    Date of Patent: August 30, 2016
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Carl J. Radens
  • Patent number: 9425196
    Abstract: A method of forming a plurality of fins having different threshold voltages from a single semiconductor layer without channel doping. The method may include; forming a first semiconductor having a uniform thickness in an unmerged region, a first merged region, and a second merged region; recessing the first semiconductor in the first and second merged regions, the first semiconductor has a different thickness in each of the unmerged region, the first merged region, and the second merged region; forming a second semiconductor on the first semiconductor in the first and second merged regions; merging the first and second semiconductors to form a first merged semiconductor in the first merged region and a second merged semiconductor in the second merged region; and forming fins in unmerged region, the first merged region, and the second merged region.
    Type: Grant
    Filed: December 8, 2015
    Date of Patent: August 23, 2016
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Ramachandra Divakaruni, Juntao Li, Fee Li Lie
  • Patent number: 9418903
    Abstract: Embodiments of the present invention provide methods and structures by which the inherent discretization of effective width can be relaxed through introduction of a fractional effective device width, thereby allowing greater flexibility for design applications, such as SRAM design optimization. A portion of some fins are clad with a capping layer or workfunction material to change the threshold voltage (Vt) for a part of the fin, rendering that part of the fin electrically inactive, which changes the effective device width (Weff). Other fins are unclad, and provide maximum area of constant threshold voltage. In this way, the effective device width of some devices is reduced. Therefore, the effective device width is controllable by controlling the level of cladding of the fin.
    Type: Grant
    Filed: May 21, 2014
    Date of Patent: August 16, 2016
    Assignee: Globalfoundries Inc.
    Inventors: Ramachandra Divakaruni, Arvind Kumar, Carl Radens
  • Publication number: 20160218222
    Abstract: A flash memory device in a dual fin single floating gate configuration is provided. Semiconductor fins are formed on a stack of a back gate conductor layer and a back gate dielectric layer. Pairs of semiconductor fins are formed in an array environment such that shallow trench isolation structures can be formed along the lengthwise direction of the semiconductor fins within the array. After formation of tunneling dielectrics on the sidewalls of the semiconductor fins, a floating gate electrode is formed between each pair of proximally located semiconductor fins by deposition of a conformal conductive material layer and an isotropic etch. A control gate dielectric and a control gate electrode are formed by deposition and patterning of a dielectric layer and a conductive material layer.
    Type: Application
    Filed: April 4, 2016
    Publication date: July 28, 2016
    Applicant: GLOBALFOUNDRIES INC.
    Inventors: Ramachandra Divakaruni, Arvind Kumar, Carl J. Radens
  • Patent number: 9397002
    Abstract: A technique relates to punchthrough stop (PTS) doping in bulk fin field effect transistors. Fins are formed on a substrate, and each pair of the fins has a fin pitch. Each of the fins has an undoped fin channel and a punchthrough stop doping region underneath the undoped fin channel. A narrow shallow trench isolation trench is formed between the fin pitch of the fins. A wide shallow trench isolation trench is formed at an outside edge of the fins. A doped layer fills the narrow shallow trench isolation trench and the wide shallow trench isolation trench. A vertical thickness of the doped layer in the narrow shallow trench isolation trench is greater than a vertical thickness of the wide shallow trench isolation trench.
    Type: Grant
    Filed: November 20, 2015
    Date of Patent: July 19, 2016
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Michael P. Belyansky, Kangguo Cheng, Ramachandra Divakaruni
  • Publication number: 20160190140
    Abstract: Structures and methods for deep trench capacitor connections are disclosed. The structure includes a reduced diameter top portion of the capacitor conductor. This increases the effective spacing between neighboring deep trench capacitors. Silicide or additional polysilicon are then deposited to complete the connection between the deep trench capacitor and a neighboring transistor.
    Type: Application
    Filed: December 24, 2014
    Publication date: June 30, 2016
    Applicant: GLOBALFOUNDRIES Inc.
    Inventors: Veeraraghavan S. Basker, Kangguo Cheng, Benjamin Ryan Cipriany, Ramachandra Divakaruni, Brian J. Greene, Ali Khakifirooz, Byeong Yeol Kim, William Larsen Nicoll
  • Publication number: 20160172498
    Abstract: A semiconductor device is provided that includes a pedestal of an insulating material present over at least one layer of a semiconductor material, and at least one fin structure in contact with the pedestal of the insulating material. Source and drain region structures are present on opposing sides of the at least one fin structure. At least one of the source and drain region structures includes at least two epitaxial material layers. A first epitaxial material layer is in contact with the at least one layer of semiconductor material. A second epitaxial material layer is in contact with the at least one fin structure. The first epitaxial material layer is separated from the at least one fin structure by the second epitaxial material layer. A gate structure present on the at least one fin structure.
    Type: Application
    Filed: February 22, 2016
    Publication date: June 16, 2016
    Inventors: KANGGUO CHENG, RAMACHANDRA DIVAKARUNI, ALI KHAKIFIROOZ, ALEXANDER REZNICEK, SOON-CHEON SEO
  • Patent number: 9349730
    Abstract: Methods and semiconductor structures formed from the methods are provided which facilitate fabricating semiconductor fin structures. The methods include, for example: providing a wafer with at least one semiconductor fin extending above a substrate; transforming a portion of the semiconductor fin(s) into an isolation layer, the isolation layer separating a semiconductor layer of the semiconductor fin(s) from the substrate; and proceeding with forming a fin device(s) of a first architectural type in a first fin region of the semiconductor fin(s), and a fin device(s) of a second architectural type in a second fin region of the semiconductor fin(s), where the first architectural type and the second architectural type are different fin device architectures.
    Type: Grant
    Filed: July 18, 2013
    Date of Patent: May 24, 2016
    Assignees: GLOBALFOUNDRIES INC., STMICROELECTRONICS, INC.
    Inventors: Ajey Poovannummoottil Jacob, Kangguo Cheng, Bruce B. Doris, Nicolas Loubet, Prasanna Khare, Ramachandra Divakaruni
  • Publication number: 20160126249
    Abstract: A plurality of fin structures containing, from bottom to top, a non-doped semiconductor portion and a second doped semiconductor portion of a first conductivity type, extend upwards from a surface of a first doped semiconductor portion of the first conductivity type. A trapping material (e.g., an electron-trapping material) is present along a bottom portion of sidewall surfaces of each non-doped semiconductor portion and on exposed portions of each first doped semiconductor portion. Functional gate structures straddle each fin structure. Metal lines are located above each fin structure and straddle each functional gate structure. Each metal line is orientated perpendicular to each functional gate structure and has a bottommost surface that is in direct physical contact with a portion of a topmost surface of each of the second doped semiconductor portions.
    Type: Application
    Filed: October 29, 2014
    Publication date: May 5, 2016
    Inventors: Ramachandra Divakaruni, Arvind Kumar, Carl J. Radens