Patents by Inventor Ashima B. Chakravarti

Ashima B. Chakravarti 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: 8900961
    Abstract: A method of selectively forming a germanium structure within semiconductor manufacturing processes removes the native oxide from a nitride surface in a chemical oxide removal (COR) process and then exposes the heated nitride and oxide surface to a heated germanium containing gas to selectively form germanium only on the nitride surface but not the oxide surface.
    Type: Grant
    Filed: October 19, 2010
    Date of Patent: December 2, 2014
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Anthony I. Chou, Toshiharu Furukawa, Steven J. Holmes, Wesley C. Natzle
  • Patent number: 8685845
    Abstract: A method for depositing epitaxial films of silicon carbon (Si:C). In one embodiment, the method includes depositing an n-type doped silicon carbon (Si:C) semiconductor material on a semiconductor deposition surface using a deposition gas precursor composed of a silane containing gas precursor, a carbon containing gas precursor, and an n-type gas dopant source. The deposition gas precursor is introduced to the semiconductor deposition surface with a hydrogen (H2) carrier gas. The method for depositing epitaxial films may include an etch reaction provided by hydrogen chloride (HCl) gas etchant and a hydrogen (H2) carrier gas.
    Type: Grant
    Filed: August 20, 2010
    Date of Patent: April 1, 2014
    Assignee: International Business Machines Corporation
    Inventors: Abhishek Dube, Ashima B. Chakravarti, Jinghong H. Li, Rainer Loesing, Dominic J. Schepis
  • Patent number: 8575655
    Abstract: Various techniques for changing the workfunction of the substrate by using a SiGe channel which, in turn, changes the bandgap favorably for a p-type metal oxide semiconductor field effect transistors (pMOSFETs) are disclosed. In the various techniques, a SiGe film that includes a low doped SiGe region above a more highly doped SiGe region to allow the appropriate threshold voltage (Vt) for pMOSFET devices while preventing pitting, roughness and thinning of the SiGe film during subsequent cleans and processing is provided.
    Type: Grant
    Filed: March 27, 2012
    Date of Patent: November 5, 2013
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Ashima B. Chakravarti, Michael P. Chudzik, Judson R. Holt, Dominic J. Schepis
  • Patent number: 8563446
    Abstract: A method for forming a trench structure is provided for a semiconductor and/or memory device, such as an DRAM device. In one embodiment, the method for forming a trench structure includes forming a trench in a semiconductor substrate, and exposing the sidewalls of the trench to an arsenic-containing gas to adsorb an arsenic containing layer on the sidewalls of the trench. A material layer is then deposited on the sidewalls of the trench to encapsulate the arsenic-containing layer between the material layer and sidewalls of the trench.
    Type: Grant
    Filed: May 18, 2012
    Date of Patent: October 22, 2013
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Jacob B. Dadson, Paul J. Higgins, Babar A. Khan, John J. Moore, Christopher C. Parks, Rohit S. Takalkar
  • Patent number: 8440547
    Abstract: Various techniques for changing the workfunction of the substrate by using a SiGe channel which, in turn, changes the bandgap favorably for a p-type metal oxide semiconductor field effect transistors (pMOSFETs) are disclosed. In the various techniques, a SiGe film that includes a low doped SiGe region above a more highly doped SiGe region to allow the appropriate threshold voltage (Vt) for pMOSFET devices while preventing pitting, roughness and thinning of the SiGe film during subsequent cleans and processing is provided.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: May 14, 2013
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Ashima B. Chakravarti, Michael P. Chudzik, Judson R. Holt, Dominic J. Schepis
  • Patent number: 8389352
    Abstract: Epitaxial deposition of silicon germanium in a semiconductor device is achieved without using masks. Nucleation delays induced by interactions with dopants present before deposition of the silicon germanium are used to determine a period over which an exposed substrate surface may be subjected to epitaxial deposition to form a layer of SiGe on desired parts with substantially no deposition on other parts. Dopant concentration may be changed to achieve desired thicknesses within preferred deposition times. Resulting deposited SiGe is substantially devoid of growth edge effects.
    Type: Grant
    Filed: February 11, 2011
    Date of Patent: March 5, 2013
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Abhishek Dube, Dominic J. Schepis
  • Patent number: 8354314
    Abstract: Epitaxial deposition of silicon germanium in a semiconductor device is achieved without using masks. Nucleation delays induced by interactions with dopants present before deposition of the silicon germanium are used to determine a period over which an exposed substrate surface may be subjected to epitaxial deposition to form a layer of SiGe on desired parts with substantially no deposition on other parts. Dopant concentration may be changed to achieve desired thicknesses within preferred deposition times. Resulting deposited SiGe is substantially devoid of growth edge effects.
    Type: Grant
    Filed: February 11, 2011
    Date of Patent: January 15, 2013
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Abhishek Dube, Dominic J. Schepis
  • Publication number: 20130009211
    Abstract: Epitaxial deposition of silicon germanium in a semiconductor device is achieved without using masks. Nucleation delays induced by interactions with dopants present before deposition of the silicon germanium are used to determine a period over which an exposed substrate surface may be subjected to epitaxial deposition to form a layer of SiGe on desired parts with substantially no deposition on other parts. Dopant concentration may be changed to achieve desired thicknesses within preferred deposition times. Resulting deposited SiGe is substantially devoid of growth edge effects.
    Type: Application
    Filed: September 14, 2012
    Publication date: January 10, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ashima B. Chakravarti, Abhishek Dube, Dominic J. Schepis
  • Publication number: 20120228736
    Abstract: A method for forming a trench structure is provided for a semiconductor and/or memory device, such as an DRAM device. In one embodiment, the method for forming a trench structure includes forming a trench in a semiconductor substrate, and exposing the sidewalls of the trench to an arsenic-containing gas to adsorb an arsenic containing layer on the sidewalls of the trench. A material layer is then deposited on the sidewalls of the trench to encapsulate the arsenic-containing layer between the material layer and sidewalls of the trench.
    Type: Application
    Filed: May 18, 2012
    Publication date: September 13, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ashima B. Chakravarti, Jacob B. Dadson, Paul J. Higgins, Babar A. Khan, John J. Moore, Christopher C. Parks, Rohit S. Takalkar
  • Publication number: 20120205749
    Abstract: Epitaxial deposition of silicon germanium in a semiconductor device is achieved without using masks. Nucleation delays induced by interactions with dopants present before deposition of the silicon germanium are used to determine a period over which an exposed substrate surface may be subjected to epitaxial deposition to form a layer of SiGe on desired parts with substantially no deposition on other parts. Dopant concentration may be changed to achieve desired thicknesses within preferred deposition times. Resulting deposited SiGe is substantially devoid of growth edge effects.
    Type: Application
    Filed: February 11, 2011
    Publication date: August 16, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ashima B. Chakravarti, Abhishek Dube, Dominic J. Schepis
  • Patent number: 8236710
    Abstract: A method for forming a trench structure is provided for a semiconductor and/or memory device, such as an DRAM device. In one embodiment, the method for forming a trench structure includes forming a trench in a semiconductor substrate, and exposing the sidewalls of the trench to an arsenic-containing gas to adsorb an arsenic containing layer on the sidewalls of the trench. A material layer is then deposited on the sidewalls of the trench to encapsulate the arsenic-containing layer between the material layer and sidewalls of the trench.
    Type: Grant
    Filed: October 7, 2010
    Date of Patent: August 7, 2012
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Jacob B. Dadson, Paul J. Higgins, Babar A. Khan, John J. Moore, Christopher C. Parks, Rohit S. Takalkar
  • Publication number: 20120181631
    Abstract: Various techniques for changing the workfunction of the substrate by using a SiGe channel which, in turn, changes the bandgap favorably for a p-type metal oxide semiconductor field effect transistors (pMOSFETs) are disclosed. In the various techniques, a SiGe film that includes a low doped SiGe region above a more highly doped SiGe region to allow the appropriate threshold voltage (Vt) for pMOSFET devices while preventing pitting, roughness and thinning of the SiGe film during subsequent cleans and processing is provided.
    Type: Application
    Filed: March 27, 2012
    Publication date: July 19, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen W. Bedell, Ashima B. Chakravarti, Michael P. Chudzik, Judson R. Holt, Dominic J. Schepis
  • Patent number: 8173524
    Abstract: Methods form epitaxial materials by forming at least two gate stacks on a silicon substrate and forming sidewall spacers on sides of the gate stacks. Such methods pattern a recess in the silicon substrate between adjacent ones of the gate stacks. The methods also provide a liner in a bottom of the recess, and epitaxially grow epitaxial material from sidewalls of the recess to fill the recess with the epitaxial material.
    Type: Grant
    Filed: January 11, 2011
    Date of Patent: May 8, 2012
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Anthony I. Chou, Abhishek Dube, Dominic J. Schepis
  • Publication number: 20120086103
    Abstract: A method for forming a trench structure is provided for a semiconductor and/or memory device, such as an DRAM device. In one embodiment, the method for forming a trench structure includes forming a trench in a semiconductor substrate, and exposing the sidewalls of the trench to an arsenic-containing gas to adsorb an arsenic containing layer on the sidewalls of the trench. A material layer is then deposited on the sidewalls of the trench to encapsulate the arsenic-containing layer between the material layer and sidewalls of the trench.
    Type: Application
    Filed: October 7, 2010
    Publication date: April 12, 2012
    Applicant: International Business Machines Corporation
    Inventors: ASHIMA B. CHAKRAVARTI, Jacob B. Dadson, Paul J. Higgins, Babar A. Khan, John J. Moore, Christopher C. Parks, Rohit S. Takalkar
  • Publication number: 20120043556
    Abstract: A method for depositing epitaxial films of silicon carbon (Si:C). In one embodiment, the method includes depositing an n-type doped silicon carbon (Si:C) semiconductor material on a semiconductor deposition surface using a deposition gas precursor composed of a silane containing gas precursor, a carbon containing gas precursor, and an n-type gas dopant source. The deposition gas precursor is introduced to the semiconductor deposition surface with a hydrogen (H2) carrier gas. The method for depositing epitaxial films may include an etch reaction provided by hydrogen chloride (HCl) gas etchant and a hydrogen (H2) carrier gas.
    Type: Application
    Filed: August 20, 2010
    Publication date: February 23, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Abhishek Dube, Ashima B. Chakravarti, Jinghong H. Li, Rainer Loesing, Dominic J. Schepis
  • Patent number: 8105955
    Abstract: An integrated circuit system includes a substrate, a carbon-containing silicon region over the substrate, a non-carbon-containing silicon region over the substrate, and a silicon-carbon region, including the non-carbon-containing silicon region and the carbon-containing silicon region.
    Type: Grant
    Filed: August 15, 2006
    Date of Patent: January 31, 2012
    Assignees: GLOBALFOUNDRIES Singapore Pte. Ltd., International Business Machines Corporation
    Inventors: Jin Ping Liu, Richard J. Murphy, Anita Madan, Ashima B. Chakravarti
  • Patent number: 8080451
    Abstract: Solutions for fabricating a semiconductor structure. One embodiment includes a method for fabricating a semiconductor structure, the method including: forming a first dielectric structure on a substrate, the first dielectric structure including silicon nitride (Si3N4); forming a second dielectric structure in proximity to the first dielectric structure; and growing a non-epitaxial thin film from a surface of the first dielectric structure; wherein the growing includes using a combination of precursor, carrier and etchant with a ratio among the precursor, carrier, and etchant being adjusted for selective growth of the thin film on the surface, and wherein the thin film includes one selected from a group consisting of: a monocrystalline material, an amorphous material, a polycrystalline material and a combination thereof.
    Type: Grant
    Filed: January 8, 2010
    Date of Patent: December 20, 2011
    Assignee: International Business Machines Corporation
    Inventors: Thomas N. Adam, Ashima B. Chakravarti, Eric C. T. Harley, Judson R. Holt
  • Patent number: 7888241
    Abstract: A method of selectively forming a germanium structure within semiconductor manufacturing processes removes the native oxide from a nitride surface in a chemical oxide removal (COR) process and then exposes the heated nitride and oxide surface to a heated germanium containing gas to selectively form germanium only on the nitride surface but not the oxide surface.
    Type: Grant
    Filed: June 9, 2008
    Date of Patent: February 15, 2011
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Anthony I. Chou, Toshiharu Furukawa, Steven J. Holmes, Wesley C. Nazle
  • Publication number: 20110034000
    Abstract: A method of selectively forming a germanium structure within semiconductor manufacturing processes removes the native oxide from a nitride surface in a chemical oxide removal (COR) process and then exposes the heated nitride and oxide surface to a heated germanium containing gas to selectively form germanium only on the nitride surface but not the oxide surface.
    Type: Application
    Filed: October 19, 2010
    Publication date: February 10, 2011
    Applicant: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Anthony I. Chou, Toshiharu Furukawa, Steven J. Holmes, Wesley C. Natzle
  • Patent number: 7838932
    Abstract: An embedded silicon carbon (Si:C) having a substitutional carbon content in excess of one percent in order to effectively increase electron mobility by application of tension to a channel region of an NFET is achieved by overfilling a gap or trench formed by transistor gate structures with Si:C and polishing an etching the Si:C to or below a surface of a raised gate structure in a super-Damascene process, leaving Si:C only in selected regions above the transistor source and drain, even though processes capable of depositing Si:C with sufficiently high substitutional carbon content are inherently non-selective.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: November 23, 2010
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Dureseti Chidambarrao, Judson R. Holt, Yaocheng Liu, Kern Rim