Patents by Inventor Rajiv V. Joshi

Rajiv V. Joshi 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: 20090302387
    Abstract: An Integrated Circuit (IC) chip that may be a bulk CMOS IC chip with silicon on insulator (SOI) Field Effect Transistors (FETs) and method of making the chip. The IC chip includes areas with pockets of buried insulator strata and FETs formed on the strata are SOI FETs. The SOI FETs may include Partially Depleted SOI (PD-SOI) FETs and Fully Depleted SOI (FD-SOI) FETs and the chip may include bulk FETs as well. The FETs are formed by contouring the surface of a wafer, conformally implanting oxygen to a uniform depth, and planarizing to remove the Buried OXide (BOX) in bulk FET regions.
    Type: Application
    Filed: August 14, 2009
    Publication date: December 10, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: RAJIV V. JOSHI, LOUIS C. HSU, OLEG GLUSCHENKOV
  • Publication number: 20090303812
    Abstract: A local on-chip programmable pulsewidth and delay generating circuit includes a clock generation circuit configured to receive a global clock signal and output a local clock signal. The clock generation circuit includes a pulse shaping portion which adjusts a pulse width of the global clock signal in accordance with at least one of a trailing edge delay and a leading edge delay. The leading edge delay is generated by a leading edge delay circuit, and the trailing edge delay is generated by a trailing edge delay circuit configured to apply a delay to a trailing edge of a pulse. The trailing edge delay circuit includes a delay chain having programmable stages of delay elements, each stage being independently controlled using control bits decoded from address latches.
    Type: Application
    Filed: August 18, 2009
    Publication date: December 10, 2009
    Inventors: Rajiv V. Joshi, Robert Maurice Houle, Kevin A. Batson
  • Publication number: 20090190413
    Abstract: A method for repairing degraded field effect transistors includes forward biasing PN junctions of one of a source and a drain of a field effect transistor (FET), and a body of the FET. Charge is injected from a substrate to a gate region to neutralize charge in the gate region. The method is applicable to CMOS devices. Repair circuits are disclosed for implementing the repairs.
    Type: Application
    Filed: January 24, 2008
    Publication date: July 30, 2009
    Inventors: Louis L. C. Hsu, Rajiv V. Joshi, Zhijian J. Yang, Ping-Chuan Wang
  • Patent number: 7566599
    Abstract: A field effect transistor (FET), integrated circuit (IC) chip including the FETs and a method of forming the FETs. The FETs include a thin channel with raised source/drain (RSD) regions at each end on an insulator layer, e.g., on an ultra-thin silicon on insulator (SOI) chip. Isolation trenches at each end of the FETs, i.e., at the end of the RSD regions, isolate and define FET islands. Insulating sidewalls at each RSD region sandwich the FET gate between the RSD regions. The gate dielectric may be a high K dielectric. Salicide on the RSD regions and, optionally, on the gates reduce device resistances.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: July 28, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rama Divakaruni, Louis C. Hsu, Rajiv V. Joshi, Carl J. Radens
  • Patent number: 7560310
    Abstract: A method of fabricating a semiconductor device includes etching a substrate formed on a backside of a semiconductor wafer to form a recess in the substrate, and forming a sputter film in the recess, the sputter film including a first material having a coefficient of thermal expansion (CTE) which is at least substantially equal to a CTE of the substrate, and a second material having a thermal conductivity which is greater than a thermal conductivity of the substrate.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: July 14, 2009
    Assignee: International Business Machines Corporation
    Inventors: Louis L. C. Hsu, Rajiv V. Joshi, Jack Allan Mandelman
  • Patent number: 7561483
    Abstract: An internally asymmetric method for evaluating static memory cell dynamic stability provide a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the internal symmetry of a static random access memory (SRAM) memory cell, operating the cell and observing changes in performance caused by the asymmetric operation, the dynamic stability of the SRAM cell can be studied over designs and operating environments. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each cross-coupled stage. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. A memory array with at least one test cell can be fabricated in a production or test wafer and internal nodes of the memory cell can be probed to provide further information.
    Type: Grant
    Filed: March 14, 2007
    Date of Patent: July 14, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Qiuyi Ye, Anirudh Devgan
  • Publication number: 20090174075
    Abstract: The invention is directed to an improved semiconductor structure, such that within the same insulating layer, Cu interconnects embedded within the same insulating level layer have a different Cu grain size than other Cu interconnects embedded within the same insulating level layer.
    Type: Application
    Filed: January 7, 2008
    Publication date: July 9, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Chih-Chao Yang, Louis C. Hsu, Rajiv V. Joshi
  • Patent number: 7558136
    Abstract: A memory cell having an asymmetric connection for evaluating dynamic stability provides a mechanism for raising the performance of memory arrays beyond present levels/yields. By operating the cell and observing changes in performance caused by the asymmetry, the dynamic stability of the SRAM cell can be studied over designs and operating environments. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each crosscoupled stage. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. A memory array with at least one test cell can be fabricated in a production or test wafer and internal nodes of the memory cell can be probed to provide further information.
    Type: Grant
    Filed: August 14, 2007
    Date of Patent: July 7, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Qiuyi Ye, Anirudh Devgan
  • Publication number: 20090172451
    Abstract: A method and computer program product for controlling a storage device using per-element selectable power supply voltages provides energy conservation in storage devices while maintaining a particular performance level. The storage device is partitioned into multiple elements, which may be sub-arrays, rows, columns or individual storage cells. Each element has a corresponding virtual power supply rail that is provided with a selectable power supply voltage. The power supply voltage provided to the virtual power supply rail for an element is set to the minimum power supply voltage unless a higher power supply voltage is required for the element to meet performance requirements. A control cell may be provided within each element that provides a control signal that selects the power supply voltage supplied to the corresponding virtual power supply rail. The state of the cell may be set via a fuse or mask, or values may be loaded into the control cells at initialization of the storage device.
    Type: Application
    Filed: March 6, 2009
    Publication date: July 2, 2009
    Inventors: Rajiv V. Joshi, Jente B Kuang, Rouwaida N. Kanj, Sani R. Nassif, Hung Cai Ngo
  • Patent number: 7551508
    Abstract: An energy efficient storage device using per-element selectable power supply voltages provides energy conservation in storage devices while maintaining a particular performance level. The storage device is partitioned into multiple elements, which may be sub-arrays, rows, columns or individual storage cells. Each element has a corresponding virtual power supply rail that is provided with a selectable power supply voltage. The power supply voltage provided to the virtual power supply rail for an element is set to the minimum power supply voltage unless a higher power supply voltage is required for the element to meet performance requirements. A control cell may be provided within each element that provides a control signal that selects the power supply voltage supplied to the corresponding virtual power supply rail. The state of the cell may be set via a fuse or mask, or values may be loaded into the control cells at initialization of the storage device.
    Type: Grant
    Filed: November 16, 2007
    Date of Patent: June 23, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Jente B Kuang, Rouwaida N. Kanj, Sani R. Nassif, Hung Cai Ngo
  • Publication number: 20090147592
    Abstract: In a memory circuit, data from all cells along a selected word line is read. Then, the read data is written back to half-selected cells and new data is written to the selected cells in the next cycle. In cases where a READ bit line (RBL) and WRITE bit line (WBL) are decoupled, RBL and WBL can be accessed simultaneously. Hence, the WRITE in the n-th cycle can be delayed to the n+1-th cycle as far as there is no data hazard such as reading data from memory before correct data are actually written to memory. As a result, there is no bandwidth loss, although the latency of the WRITE operation increases. WRITE stability issues in previous configurations with decoupled RBL and WBL are thus addressed.
    Type: Application
    Filed: December 5, 2008
    Publication date: June 11, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Rajiv V. Joshi, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20090147560
    Abstract: A design structure embodied in a machine readable medium for use in a design process, the design structure representing a novel semiconductor SRAM cell structure that includes at least two pull-up transistors, two pull-down transistors, and two pass-gate transistors. In one embodiment, the SRAM cell is an 8T SRAM cell structure implements a series gating feature for implementing Column Select (CS) and Row Select (WL) cell storage access with enhanced stability. Particularly, the 8-T approach adds two pass-gates, two series connected transistor devices connected at complementary nodes of two cross-coupled inverters, to control column select and row (word) select. In the other embodiment, the SRAM cell is a 9T SRAM cell structure includes a transmission gate to implement Column Select (CS) and Row Select (WL) cell storage access with enhanced stability. The 9-T approach adds three transistors to perform ANDING function to separate the row select and column select signal functions.
    Type: Application
    Filed: December 7, 2007
    Publication date: June 11, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Rajiv V. Joshi, Yue Tan, Robert C. Wong
  • Publication number: 20090132873
    Abstract: A method and system for determining element voltage selection control values for a storage device provides energy conservation in storage arrays while maintaining a particular performance level. The storage device is partitioned into multiple elements, which may be sub-arrays, rows, columns or individual storage cells. Each element has a corresponding virtual power supply rail that is provided with a selectable power supply voltage. At test time, digital control values are determined for selection circuits for each element that set the virtual power supply rail to the minimum power supply voltage, unless a higher power supply voltage is required for the element to meet performance requirements. The set of digital control values can then be programmed into a fuse or used to adjust a mask at manufacture, or supplied on media along with the storage device and loaded into the device at system initialization.
    Type: Application
    Filed: November 16, 2007
    Publication date: May 21, 2009
    Inventors: Rajiv V. Joshi, Jente B. Kuang, Rouwaida N. Kanj, Sani R. Nassif, Hung Cai Ngo
  • Publication number: 20090129193
    Abstract: An energy efficient storage device using per-element selectable power supply voltages provides energy conservation in storage devices while maintaining a particular performance level. The storage device is partitioned into multiple elements, which may be sub-arrays, rows, columns or individual storage cells. Each element has a corresponding virtual power supply rail that is provided with a selectable power supply voltage. The power supply voltage provided to the virtual power supply rail for an element is set to the minimum power supply voltage unless a higher power supply voltage is required for the element to meet performance requirements. A control cell may be provided within each element that provides a control signal that selects the power supply voltage supplied to the corresponding virtual power supply rail. The state of the cell may be set via a fuse or mask, or values may be loaded into the control cells at initialization of the storage device.
    Type: Application
    Filed: November 16, 2007
    Publication date: May 21, 2009
    Inventors: Rajiv V. Joshi, Jente B. Kuang, Rouwaida N. Kanj, Sani R. Nassif, Hung Cai Ngo
  • Publication number: 20090132849
    Abstract: A method and computer program for selecting circuit repairs using redundant elements with consideration of aging effects provides a mechanism for raising short-term and long-term performance of memory arrays beyond present levels/yields. Available redundant elements are used as replacements for selected elements in the array. The elements for replacement are selected by BOL (beginning-of-life) testing at a selected operating point that maximizes the end-of-life (EOL) yield distribution as among a set of operating points at which post-repair yield requirements are met at beginning-of-life (BOL). The selected operating point is therefore the “best” operating point to improve yield at EOL for a desired range of operating points or maximize the EOL operating range. For a given BOL repair operating point, the yield at EOL is computed. The operating point having the best yield at EOL is selected and testing is performed at that operating point to select repairs.
    Type: Application
    Filed: November 16, 2007
    Publication date: May 21, 2009
    Inventors: Chad A. Adams, Rajiv V. Joshi, Rouwaida N. Kanj, Sani R. Nassif
  • Patent number: 7532501
    Abstract: A memory cell (e.g., static random access memory (SRAM) cell) includes a plurality of back-gated n-type field effect transistors (nFETs), and a plurality of double-gated p-type field effect transistors (pFETs) operatively coupled to the plurality of nFETs.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: May 12, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Keunwoo Kim, Edward Joseph Nowak, Richard Quimby Williams
  • Publication number: 20090116307
    Abstract: A circuit and method includes first circuits powered by a first supply voltage and second circuits powered by a second supply voltage. A level shifter is coupled between the first circuits and the second circuits. The level shifter is configured to select a supply voltage output for a circuit including one of the first supply voltage and the second supply voltage in accordance an input signal, where the input signal depends on at least one of an operation to be performed and component performing the operation.
    Type: Application
    Filed: November 6, 2007
    Publication date: May 7, 2009
    Inventors: Scott R. Cottier, Sang Hoo Dhong, Rajiv V. Joshi, Juergen Pille, Osamu Takahashi
  • Publication number: 20090111257
    Abstract: Anti-reverse engineering techniques are provided. In one aspect, a method for forming at least one feature in an insulating layer is provided. The method comprises the following steps. Ions are selectively implanted in the insulating layer so as to form at least one implant region within the insulating layer, the implanted ions being configured to alter an etch rate through the insulating layer within the implant region. The insulating layer is etched to, at the same time, form at least one void both within the implant region and outside of the implant region, wherein the etch rate through the insulating layer within the implant region is different from an etch rate through the insulating layer outside of the implant region. The void is filled with at least one conductor material to form the feature in the insulating layer.
    Type: Application
    Filed: October 26, 2007
    Publication date: April 30, 2009
    Applicant: International Business Machines Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi, David W. Kruger
  • Patent number: 7521760
    Abstract: An Integrated Circuit (IC) chip that may be a bulk CMOS IC chip with silicon on insulator (SOI) Field Effect Transistors (FETs) and method of making the chip. The IC chip includes areas with pockets of buried insulator strata and FETs formed on the strata are SOI FETs. The SOI FETs may include Partially Depleted SOI (PD-SOI) FETs and Fully Depleted SOI (FD-SOI) FETs and the chip may include bulk FETs as well. The FETs are formed by contouring the surface of a wafer, conformally implanting oxygen to a uniform depth, and planarizing to remove the Buried OXide (BOX) in bulk FET regions.
    Type: Grant
    Filed: July 10, 2007
    Date of Patent: April 21, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Louis C. Hsu, Oleg Gluschenkov
  • Patent number: 7515491
    Abstract: A method for evaluating leakage effects on static memory cell access time provides a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the states of other static memory cells connected to the same bitline as a static memory cell under test, the effect of leakage on the access time of the cell can be observed. The leakage effects can further be observed while varying the internal symmetry of the memory cell, operating the cell and observing changes in performance caused by the asymmetric operation. The asymmetry can be introduced by splitting one or both power supply rail inputs to the cell and providing differing power supply voltages or currents to each cross-coupled stage.
    Type: Grant
    Filed: March 14, 2007
    Date of Patent: April 7, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Qiuyi Ye, Anirudh Devgan