Patents by Inventor Pranita Kulkarni

Pranita Kulkarni 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: 20130193515
    Abstract: An SRAM structure and method which includes a semiconductor on insulator (SOI) substrate which includes a semiconductor substrate, an insulating layer and a semiconductor on insulator (SOI) layer. The SOI layer has a first thickness. The SRAM structure further includes a FinFET transistor formed on the SOI substrate including a first defined portion of the SOI layer of the first thickness forming an active layer of the FinFET transistor and a gate dielectric on the first defined portion of the SOI layer and a planar transistor formed on the SOI substrate including a second defined portion of the SOI layer of a second thickness forming an active layer of the planar transistor and a gate dielectric on the second defined portion of the SOI layer. The first thickness is greater than the second thickness. Also included is a gate electrode on the FinFET transistor and the planar transistor.
    Type: Application
    Filed: January 26, 2012
    Publication date: August 1, 2013
    Applicant: International Business Machines Corporation
    Inventors: Kangguo Cheng, Wilfried E.-A. Haensch, Ali Khakifirooz, Pranita Kulkarni
  • Patent number: 8492839
    Abstract: In one exemplary embodiment, a semiconductor structure includes: a semiconductor-on-insulator substrate with a top semiconductor layer overlying an insulation layer and the insulation layer overlies a bottom substrate layer; at least one first device at least partially overlying and disposed upon a first portion of the top semiconductor layer, where the first portion has a first thickness, a first width and a first depth; and at least one second device at least partially overlying and disposed upon a second portion of the top semiconductor layer, where the second portion has a second thickness, a second width and a second depth, where at least one of the following holds: the first thickness is greater than the second thickness, the first width is greater than the second width and the first depth is greater than the second depth.
    Type: Grant
    Filed: August 24, 2010
    Date of Patent: July 23, 2013
    Assignee: International Business Machines Corporation
    Inventors: Bruce B. Doris, Kangguo Cheng, Ali Khakifirooz, Pranita Kulkarni, Ghavam G. Shahidi
  • Patent number: 8492854
    Abstract: A structure has at least one field effect transistor having a gate stack disposed between raised source drain structures that are adjacent to the gate stack. The gate stack and raised source drain structures are disposed on a surface of a semiconductor material. The structure further includes a layer of field dielectric overlying the gate stack and raised source drain structures and first contact metal and second contact metal extending through the layer of field dielectric. The first contact metal terminates in a first trench formed through a top surface of a first raised source drain structure, and the second contact metal terminates in a second trench formed through a top surface of a second raised source drain structure. Each trench has silicide formed on sidewalls and a bottom surface of at least a portion of the trench. Methods to fabricate the structure are also disclosed.
    Type: Grant
    Filed: September 25, 2012
    Date of Patent: July 23, 2013
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Bruce B. Doris, Ali Khakifirooz, Pranita Kulkarni, Christian Lavoie
  • Patent number: 8486776
    Abstract: Strained Si and strained SiGe on insulator devices, methods of manufacture and design structures is provided. The method includes growing an SiGe layer on a silicon on insulator wafer. The method further includes patterning the SiGe layer into PFET and NFET regions such that a strain in the SiGe layer in the PFET and NFET regions is relaxed. The method further includes amorphizing by ion implantation at least a portion of an Si layer directly underneath the SiGe layer. The method further includes performing a thermal anneal to recrystallize the Si layer such that a lattice constant is matched to that of the relaxed SiGe, thereby creating a tensile strain on the NFET region. The method further includes removing the SiGe layer from the NFET region. The method further includes performing a Ge process to convert the Si layer in the PFET region into compressively strained SiGe.
    Type: Grant
    Filed: September 21, 2010
    Date of Patent: July 16, 2013
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Kangguo Cheng, Bruce B. Doris, Ali Khakifirooz, Pranita Kulkarni, Katherine L. Saenger
  • Publication number: 20130178022
    Abstract: A method is provided for fabricating a transistor. According to the method, a second semiconductor layer is formed on a first semiconductor layer, and a dummy gate structure is formed on the second semiconductor layer. A gate spacer is formed on sidewalls of the dummy gate structure, and the dummy gate structure is removed to form a cavity. The second semiconductor layer beneath the cavity is removed. A gate dielectric is formed on the first portion of the first semiconductor layer and adjacent to the sidewalls of the second semiconductor layer and sidewalls of the gate spacer. A gate conductor is formed on the first portion of the gate dielectric and abutting the second portion of the gate dielectric. Raised source/drain regions are formed in the second semiconductor layer, with at least part of the raised source/drain regions being below the gate spacer.
    Type: Application
    Filed: September 14, 2012
    Publication date: July 11, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kangguo CHENG, Ali KHAKIFIROOZ, Sivananda KANAKASABAPATHY, Pranita KULKARNI, Balasubramanian S. HARAN
  • Publication number: 20130175606
    Abstract: A structure has at least one field effect transistor having a gate stack disposed between raised source drain structures that are adjacent to the gate stack. The gate stack and raised source drain structures are disposed on a surface of a semiconductor material. The structure further includes a layer of field dielectric overlying the gate stack and raised source drain structures and first contact metal and second contact metal extending through the layer of field dielectric. The first contact metal terminates in a first trench formed through a top surface of a first raised source drain structure, and the second contact metal terminates in a second trench formed through a top surface of a second raised source drain structure. Each trench has silicide formed on sidewalls and a bottom surface of at least a portion of the trench. Methods to fabricate the structure are also disclosed.
    Type: Application
    Filed: January 6, 2012
    Publication date: July 11, 2013
    Inventors: Kangguo Cheng, Bruce B. DORIS, Ali KHAKIFIROOZ, Pranita KULKARNI, Christian LAVOIE
  • Publication number: 20130175594
    Abstract: An integrated circuit comprising an N+ type layer, a buffer layer arranged on the N+ type layer; a P type region formed on with the buffer layer; an insulator layer overlying the N+ type layer, a silicon layer overlying the insulator layer, an embedded RAM FET formed in the silicon layer and connected with a conductive node of a trench capacitor that extends into the N+ type layer, the N+ type layer forming a plate electrode of the trench capacitor, a first contact through the silicon layer and the insulating layer and electrically connecting to the N+ type layer, a first logic RAM FET formed in the silicon layer above the P type region, the P type region functional as a P-type back gate of the first logic RAM FET, and a second contact through the silicon layer and the insulating layer and electrically connecting to the P type region.
    Type: Application
    Filed: July 18, 2012
    Publication date: July 11, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Veeraraghavan S. Basker, Kangguo Cheng, Bruce B. Doris, Terence B. Hook, Ali Khakifirooz, Pranita Kulkarni, Tenko Yamashita, Chun-Chen Yeh
  • Publication number: 20130175661
    Abstract: A structure includes a silicon substrate; at least two wells in the silicon substrate; and a deep trench isolation (DTI) separating the two wells. The DTI has a top portion and a bottom portion having a width that is larger than a width of the top portion. The structure further includes at least two semiconductor devices disposed over one of the wells, where the at least two semiconductor devices are separated by a shallow trench isolation (STI). In the structure sidewalls of the top portion of the DTI and sidewalls of the STI are comprised of doped, re-crystallized silicon. The doped, re-crystallized silicon can be formed by an angled ion implant that uses, for example, one of Xe, In, BF2, B18H22, C16H10, Si, Ge or As as an implant species to amorphize the silicon, and by annealing the amorphized silicon to re-crystallize the amorphized silicon.
    Type: Application
    Filed: September 20, 2012
    Publication date: July 11, 2013
    Applicant: International Business Machines Corporation
    Inventors: Jin Cai, Kangguo Cheng, Ali Khakifirooz, Pranita Kulkarni
  • Publication number: 20130175579
    Abstract: A transistor includes a first semiconductor layer. A second semiconductor layer is located on the first semiconductor layer. A portion of the second semiconductor layer is removed to expose a first portion of the first semiconductor layer and to provide vertical sidewalls of the second semiconductor layer. A gate spacer is located on the second semiconductor layer. A gate dielectric includes a first portion located on the first portion of the first semiconductor layer and a second portion adjacent to the vertical sidewalls of the second semiconductor layer. A gate conductor is located on the first portion of the gate dielectric and abuts the gate dielectric second portion. A channel region is located in at least part of the first portion of the first semiconductor layer. Raised source/drain regions are located in the second semiconductor layer. At least part of the raised source/drain regions is located below the gate spacer.
    Type: Application
    Filed: January 10, 2012
    Publication date: July 11, 2013
    Applicant: International Business Machines Corporation
    Inventors: Kangguo Cheng, Ali Khakifirooz, Sivananda Kanakasabapathy, Pranita Kulkarni, Balasubramanian S. Haran
  • Publication number: 20130175595
    Abstract: An integrated circuit includes an SOI substrate with a unitary N+ layer below the BOX, a P region in the N+ layer, an eDRAM with an N+ plate, and logic/SRAM devices above the P region. The P region functions as a back gate of the logic/SRAM devices. An optional intrinsic (undoped) layer can be formed between the P back gate layer and the N+ layer to reduce the junction field and lower the junction leakage between the P back gate and the N+ layer. In another embodiment an N or N+ back gate can be formed in the P region. The N+ back gate functions as a second back gate of the logic/SRAM devices. The N+ plate of the SOI eDRAM, the P back gate, and the N+ back gate can be electrically biased at the same or different voltage potentials. Methods to fabricate the integrated circuits are also disclosed.
    Type: Application
    Filed: January 6, 2012
    Publication date: July 11, 2013
    Applicant: International Business Machines Corporation
    Inventors: Kangguo Cheng, Bruce B. Doris, Terence B. Hook, Ali Khakifirooz, Pranita Kulkarni
  • Patent number: 8482078
    Abstract: A method includes forming isolation regions in a semiconductor substrate to define a first field effect transistor (FET) region, a second FET region, and a diode region, forming a first gate stack in the first FET region and a second gate stack in the second FET region, forming a layer of spacer material over the second FET region and the second gate stack, forming a first source region and a first drain region in the first FET region and a first diode layer in the diode region using a first epitaxial growth process, forming a hardmask layer over the first source region, the first drain region, the first gate stack and a portion of the first diode layer, and forming a second source region and a second drain region in the first FET region and a second diode layer on the first diode layer using a second epitaxial growth process.
    Type: Grant
    Filed: May 10, 2011
    Date of Patent: July 9, 2013
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Ali Khakifirooz, Pranita Kulkarni, Ghavam G. Shahidi
  • Patent number: 8470678
    Abstract: A method for inducing a tensile stress in a channel of a field effect transistor (FET) includes forming a nitride film over the FET; forming a contact hole to the FET through the nitride film; and performing ultraviolet (UV) curing of the nitride film after forming the contact hole to the FET through the nitride film, wherein the UV cured nitride film induces the tensile stress in the channel of the FET.
    Type: Grant
    Filed: February 24, 2011
    Date of Patent: June 25, 2013
    Assignee: International Business Machines Corporation
    Inventors: Ming Cai, Dechao Guo, Chun-chen Yeh, Pranita Kulkarni
  • Publication number: 20130154001
    Abstract: Multigate transistor devices and methods of their fabrication are disclosed. In accordance with one method, a fin and a gate structure that is disposed on a plurality of surfaces of the fin are formed. In addition, at least a portion of an extension of the fin is removed to form a recessed portion that is below the gate structure, is below a channel region of the fin, and includes at least one angled indentation. Further, a terminal extension is grown in the at least one angled indentation below the channel region and along a surface of the channel region such that the terminal extension provides a stress on the channel region to enhance charge carrier mobility in the channel region.
    Type: Application
    Filed: December 14, 2011
    Publication date: June 20, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: MING CAI, DECHAO GUO, PRANITA KULKARNI, CHUN-CHEN YEH
  • Publication number: 20130154029
    Abstract: Multigate transistor devices and methods of their fabrication are disclosed. In accordance with one method, a fin and a gate structure that is disposed on a plurality of surfaces of the fin are formed. In addition, at least a portion of an extension of the fin is removed to form a recessed portion that is below the gate structure, is below a channel region of the fin, and includes at least one angled indentation. Further, a terminal extension is grown in the at least one angled indentation below the channel region and along a surface of the channel region such that the terminal extension provides a stress on the channel region to enhance charge carrier mobility in the channel region.
    Type: Application
    Filed: September 12, 2012
    Publication date: June 20, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ming Cai, Dechao Guo, Pranita Kulkarni, Chun-Chen Yeh
  • Publication number: 20130146975
    Abstract: A method, semiconductor device, and integrated circuit with a high-k/metal gate without high-k direct contact with STI. A high-k dielectric and a pad film are deposited directly onto a semiconductor substrate. Shallow trench isolation is performed, with shallow trenches etched directly into the pad film, the high-k material, and the substrate. The shallow trench is lined with an oxygen diffusion barrier and is subsequently filled with an insulating dielectric material. Thereafter the pad film and the insulating dielectric are recessed to a point where the oxygen diffusion barrier still remains between the insulating dielectric and the high-k material, preventing any contact there between. Afterwards a conductive gate is formed overlying the device.
    Type: Application
    Filed: December 12, 2011
    Publication date: June 13, 2013
    Applicant: International Business Machines Corporation
    Inventors: Kangguo Cheng, Bruce B. Doris, Ali Khakifirooz, Pranita Kulkarni
  • Patent number: 8455932
    Abstract: A common cut mask is employed to define a gate pattern and a local interconnect pattern so that local interconnect structures and gate structures are formed with zero overlay variation relative to one another. A local interconnect structure may be laterally spaced from a gate structure in a first horizontal direction, and contact another gate structure in a second horizontal direction that is different from the first horizontal direction. Further, a gate structure may be formed to be collinear with a local interconnect structure that adjoins the gate structure. The local interconnect structures and the gate structures are formed by a common damascene processing step so that the top surfaces of the gate structures and the local interconnect structures are coplanar with each other.
    Type: Grant
    Filed: May 6, 2011
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: Ali Khakifirooz, Kangguo Cheng, Bruce B. Doris, Wilfried E. Haensch, Balasubramanian S. Haran, Pranita Kulkarni
  • Patent number: 8455308
    Abstract: A semiconductor device and a method of fabricating a semiconductor device. The semiconductor device includes a semiconductor substrate, an insulating layer, a first semiconductor layer, a dielectric layer, a second semiconductor layer, a source and drain junction, a gate, and a spacer. The method includes the steps of forming a semiconductor substrate, forming a shallow trench isolation layer, growing a first epitaxial layer, growing a second epitaxial layer, forming a gate, forming a spacer, performing a reactive ion etching, removing a portion of the first epitaxial layer, filling the void with a dielectric, etching back a portion of the dielectric, growing a silicon layer, implanting a source and drain junction, and forming an extension.
    Type: Grant
    Filed: March 16, 2011
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Bruce Doris, Pranita Kulkarni, Ghavam Shahidi
  • Patent number: 8450807
    Abstract: A method and structure for forming a field effect transistor with reduced contact resistance are provided. The reduced contact resistance is manifested by a reduced metal semiconductor alloy contact resistance and a reduced conductively filled via contact-to-metal semiconductor alloy contact resistance. The reduced contact resistance is achieved in this disclosure by texturing the surface of the transistor's source region and/or the transistor's drain region. Typically, both the source region and the drain region are textured in the present disclosure. The textured source region and/or the textured drain region have an increased area as compared to a conventional transistor that includes a flat source region and/or a flat drain region. A metal semiconductor alloy, e.g., a silicide, is formed on the textured surface of the source region and/or the textured surface of the drain region. A conductively filled via contact is formed atop the metal semiconductor alloy.
    Type: Grant
    Filed: March 9, 2010
    Date of Patent: May 28, 2013
    Assignee: International Business Machines Corporation
    Inventors: Bruce B. Doris, Kangguo Cheng, Ali Khakifirooz, Pranita Kulkarni
  • Patent number: 8445345
    Abstract: A method of forming a complementary metal oxide semiconductor (CMOS) structure having multiple threshold voltage devices includes forming a first transistor device and a second transistor device on a semiconductor substrate. The first transistor device and second transistor device initially have sacrificial dummy gate structures. The sacrificial dummy gate structures are removed and a set of vertical oxide spacers are selectively formed for the first transistor device. The set of vertical oxide spacers are in direct contact with a gate dielectric layer of the first transistor device such that the first transistor device has a shifted threshold voltage with respect to the second transistor device.
    Type: Grant
    Filed: September 8, 2011
    Date of Patent: May 21, 2013
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Bruce B. Doris, Ali Khakifirooz, Pranita Kulkarni
  • Patent number: 8445356
    Abstract: Disclosed is a method of forming a structure and a resulting structure. The method includes providing a semiconductor substrate; forming a first opening to a first depth in the semiconductor substrate; amorphizing semiconductor sidewalls of an upper portion of the first opening leaving unamorphized semiconductor sidewalls in a lower portion of the first opening; enlarging only the lower portion of the first opening using an etch process that is selective to the unamorphized semiconductor sidewalls; filling the first opening with an insulator material to form a deep trench isolation (DTI) structure and implanting a first well region and a second well region into the semiconductor substrate. The first well and the second well are separated from one another by the enlarged lower portion of the first opening. In the structure sidewalls of a top portion of a DTI and sidewalls of an STI are formed of doped, re-crystallized silicon.
    Type: Grant
    Filed: January 5, 2012
    Date of Patent: May 21, 2013
    Assignee: International Business Machines Corporation
    Inventors: Jin Cai, Kangguo Cheng, Ali Khakifirooz, Pranita Kulkarni