Patents by Inventor Rajive Joshi

Rajive 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: 20070058466
    Abstract: Internally asymmetric methods and circuits 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: Application
    Filed: September 13, 2005
    Publication date: March 15, 2007
    Inventors: Rajiv Joshi, Qiuyi Ye, Anirudh Devgan
  • Publication number: 20070058448
    Abstract: Bitline variable methods and circuits for evaluating static memory cell dynamic stability provide a mechanism for raising the performance of memory arrays beyond present levels/yields. By altering the bitline pre-charge voltage of a static random access memory (SRAM) memory cell, operating the cell and observing changes in performance caused by the changes in the bitline voltage, the dynamic stability of the SRAM cell can be studied over designs and operating environments. Alternatively or in combination, the loading at the outputs of the cell can altered in order to affect the performance of the cell. In addition, cell power supply voltages can be split and set to different levels in order to study the effect of cell asymmetry in combination with bitline pre-charge voltage differences.
    Type: Application
    Filed: September 13, 2005
    Publication date: March 15, 2007
    Inventors: Rajiv Joshi, Qiuyi Ye, Anirudh Devgan
  • Publication number: 20070045749
    Abstract: A method for forming a CMOS well structure including forming a plurality of first conductivity type wells over a substrate, each of the plurality of first conductivity type wells formed in a respective opening in a first mask. A cap is formed over each of the first conductivity type wells, and the first mask is removed. Sidewall spacers are formed on sidewalls of each of the first conductivity type wells. A plurality of second conductivity type wells are formed, each of the plurality of second conductivity type wells are formed between respective first conductivity type wells. A plurality of shallow trench isolations are formed between the first conductivity type wells and second conductive type wells. The plurality of first conductivity type wells are formed by a first selective epitaxial growth process, and the plurality of second conductivity type wells are formed by a second selective epitaxial growth process.
    Type: Application
    Filed: October 23, 2006
    Publication date: March 1, 2007
    Inventors: Wilfried Haensch, Terence Hook, Louis Hsu, Rajiv Joshi, Werner Rausch
  • Publication number: 20070049007
    Abstract: An interconnect structure and a method for forming the same are described. Specifically, under the present invention, a gouge is created within a via formed in the interconnect structure before any trenches are formed. This prevents the above-mentioned trench damage from occurring. That is, the bottom surface of the trenches will have a roughness of less than approximately 20 nm, and preferably less than approximately 10 nm. In addition to the via, gouge and trench(es), the interconnect structure of the present invention includes at least two levels of metal wiring. Further, in a typical embodiment, the interconnect structure utilizes any dielectrics having a dielectric constant no greater than approximately 5.0.
    Type: Application
    Filed: August 31, 2005
    Publication date: March 1, 2007
    Applicant: International Business Machines Corporation
    Inventors: Chih-Chao Yang, Louis Hsu, Rajiv Joshi
  • Publication number: 20070018257
    Abstract: Techniques are provided for selectively biasing wells in a circuit, such as a Complementary Metal Oxide Semiconductor (CMOS) circuit, that has two types of transistors, one type formed on a substrate and another type formed on the wells. For example, the circuit can be a memory circuit, and the selective well bias can be changed depending on whether a READ or WRITE operation is being conducted. In another aspect, cells in a memory circuit can be subjected to variable bias depending on conditions, such as, again, whether a READ or WRITE operation is underway.
    Type: Application
    Filed: July 19, 2005
    Publication date: January 25, 2007
    Applicant: International Business Machines Corporation
    Inventor: Rajiv Joshi
  • Publication number: 20060279334
    Abstract: A level converter for interfacing two circuits supplied by different supply voltages, and integrated circuit including the level converter interfacing circuit in two different voltage islands. A first buffer is supplied by a virtual supply and receives an input signal from a lower voltage circuit. The first buffer drives a second buffer, which is supplied by a higher supply voltage. An output from the second buffer switches a supply select to selectively pass the higher supply voltage or a reduced supply voltage to the first buffer.
    Type: Application
    Filed: August 23, 2006
    Publication date: December 14, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Anthony Correale, Rajiv Joshi, David Kung, Zhigang Pan, Ruchir Puri
  • Publication number: 20060274569
    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: Application
    Filed: June 2, 2005
    Publication date: December 7, 2006
    Applicant: International Business Machines Corporation
    Inventors: Rajiv Joshi, Keunwoo Kim, Edward Nowak, Richard Williams
  • Publication number: 20060256605
    Abstract: A random access memory includes a logic circuit coupled to a power supply of a column having a memory cell. The logic circuit adjusts the supply voltage for the memory cell in the column in accordance with a control signal. A control circuit is coupled to the logic circuit, which generates the control signal in accordance with an operation type and whether the column is selected, such that the logic circuit selects the supply voltage in accordance with the control signal. The cell may include high mobility devices to improve performance.
    Type: Application
    Filed: May 13, 2005
    Publication date: November 16, 2006
    Inventor: Rajiv Joshi
  • Publication number: 20060250860
    Abstract: A random access memory includes a memory cell having an access device. The access device is switched on or off in accordance with a signal on a wordline to conduct a memory operation through the access device. A logic circuit is coupled to the wordline to delay or gate the wordline signal until an enable signal has arrived at the logic circuit. The access device improves stability and eliminates early read problems.
    Type: Application
    Filed: July 6, 2006
    Publication date: November 9, 2006
    Inventor: Rajiv Joshi
  • Publication number: 20060203581
    Abstract: An efficient method and computer program for modeling and improving stating memory performance across process variations and environmental conditions provides a mechanism for raising the performance of memory arrays beyond present levels/yields. Statistical (Monte-Carlo) analyses of subsets of circuit parameters are performed for each of several memory performance variables and then sensitivities of each performance variable to 15 each of the circuit parameters are determined. The memory cell design parameters and/or operating conditions of the memory cells are then adjusted in conformity with the sensitivities, resulting in improved memory yield and/or performance. Once a performance level is attained, the sensitivities can then be used to alter the probability distributions of the performance variables to achieve a higher yield.
    Type: Application
    Filed: March 10, 2005
    Publication date: September 14, 2006
    Inventors: Rajiv Joshi, Anirudh Devgan
  • Publication number: 20060192612
    Abstract: A capacitor circuit having improved reliability includes at least first and second capacitors, a first terminal of the first capacitor connecting to a first source providing a first voltage, a first terminal of the second capacitor connecting to a second source providing a second voltage, the first voltage being greater than the second voltage. The capacitor further includes a voltage comparator having a first input for receiving a voltage representative of the first voltage, a second input for receiving a third voltage provided by a third source, and an output for generating a control signal. The control signal is a function of a difference between the voltage representative of the first voltage and the third voltage. A switch is connected to second terminals of the first and second capacitors.
    Type: Application
    Filed: February 25, 2005
    Publication date: August 31, 2006
    Applicant: International Business Machines Corporation
    Inventors: Louis Hsu, Rajiv Joshi, Jack Mandelman
  • Publication number: 20060189110
    Abstract: A semiconductor structure having a body capacitance plate, which is formed with a process that assures that the body capacitance plate is self-aligned to both the source line (SL) diffusion and the bitline diffusion is provided. Thus the amount of overlap between the SL and the bitline diffusions and the body capacitance plate is precisely controlled. More specifically, the present invention forms the structure of a 1T-capacitorless SOI body charge storage cell having sidewall capacitor plates using a process that assures that there is 1) minimal overlap between plate and source/drain diffusions, and 2) that the minimal overlap obtained in the present invention is precisely controlled and is not subject to alignment tolerances. The inventive cell results in larger signal margin, improved performance, smaller chip size, and reduced dynamic power dissipation relative to the prior art.
    Type: Application
    Filed: February 24, 2005
    Publication date: August 24, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Jack Mandelman, Louis Hsu, Rajiv Joshi
  • Publication number: 20060176732
    Abstract: A CMOS static random access memory (SRAM) and a bit select for the SRAM. The bit select includes a dual single-ended sense receiving a difference signal on a bit line pair and selectively sensing signals developing on each bit line independently of the other. Single ended outputs from the dual-ended sense are provided to an output driver. The output driver provides a pair of selectively-complementary output signals.
    Type: Application
    Filed: February 10, 2005
    Publication date: August 10, 2006
    Inventors: Yuen Chan, Timothy Charest, Rajiv Joshi, Antonio Pelella
  • Publication number: 20060176095
    Abstract: An output L1/L2 staging latch has dual rail inputs that up date the state of the L1 latch whenever the inputs are valid. Static outputs of the L1 latch are latched into the L2 by the L2 clock signal. The L2 latch has a static output that is available immediately, and a dual rail dynamic output whose timing is controlled by a clock signal.
    Type: Application
    Filed: February 9, 2005
    Publication date: August 10, 2006
    Applicant: International Business Machines Corporation
    Inventors: Yuen Chan, Timothy Charest, Rajiv Joshi
  • Publication number: 20060157788
    Abstract: The present invention generally concerns fabrication methods and device architectures for use in memory circuits, and more particularly concerns hybrid silicon-on-insulator (SOI) and bulk architectures for use in memory circuits. Once aspect of the invention concerns CMOS SRAM cell architectures where at least one pair of adjacent NFETs in an SRAM cell have body regions linked by a leakage path diffusion region positioned beneath shallow source/drain diffusions, where the leakage path diffusion region extends from the bottom of the source/drain diffusion to the buried oxide layer, and at least one pair of NFETs from adjacent SRAM cells which have body regions linked by a similar leakage path diffusion region beneath adjacent source/drain diffusions.
    Type: Application
    Filed: January 19, 2005
    Publication date: July 20, 2006
    Applicant: International Business Machines Corporation
    Inventors: Rajiv Joshi, Richard Wachnik, Yue Tan, Kerry Bernstein
  • Publication number: 20060146621
    Abstract: A test circuit and programmable voltage divider that may be used in the test circuit. The programmable voltage divider develops a voltage difference signal that may be digitally selected. The test circuit may be used to test and characterize sense amplifiers. The programmable voltage divider develops a signal with a selected polarity and magnitude that is provided to a sense amplifier being tested. The sense amplifier is set and its output latched. The latch contents are checked against an expected value. The difference voltage may be changed and the path retested to find passing and failing points.
    Type: Application
    Filed: January 3, 2005
    Publication date: July 6, 2006
    Inventors: Yuen Chan, Rajiv Joshi
  • Publication number: 20060109733
    Abstract: A multi-port register file, integrated circuit (IC) chip including one or more multi-port register files and method of reading data from the multi-port register file. The supply to storage latches in multi-port register file is selectively bootstrapped above the supply voltage during accesses.
    Type: Application
    Filed: November 22, 2004
    Publication date: May 25, 2006
    Inventors: Rajiv Joshi, Azeez Bhavnagarwala
  • Publication number: 20060098499
    Abstract: A random access memory includes a memory cell having an access device. The access device is switched on or off in accordance with a signal on a wordline to conduct a memory operation through the access device. A logic circuit is coupled to the wordline to delay or gate the wordline signal until an enable signal has arrived at the logic circuit. The access device improves stability and eliminates early read problems.
    Type: Application
    Filed: November 10, 2004
    Publication date: May 11, 2006
    Inventor: Rajiv Joshi
  • Publication number: 20060059376
    Abstract: A low power consumption pipeline circuit architecture has power partitioned pipeline stages. The first pipeline stage is non-power-gated for fast response in processing input data after receipt of a valid data signal. A power-gated second pipeline stage has two power-gated modes. Normally the power rail in the power-gated second pipeline stage is charged to a first voltage potential of a pipeline power supply. In the first power gated mode, the power rail is charged to a threshold voltage below the first voltage potential to reduce leakage. In the second power gated mode. the power rail is decoupled from the first voltage potential. A power-gated third pipeline stage has its power rail either coupled to the first voltage potential or power-gated where its power rail is decoupled from the first voltage potential. The power rail of the second power-gated pipeline stage charges to the first voltage potential before the third power-gated pipeline stage.
    Type: Application
    Filed: September 16, 2004
    Publication date: March 16, 2006
    Applicant: International Business Machines Corporation
    Inventors: Hung Ngo, Jente Kuang, Kevin Nowka, Rajiv Joshi
  • Publication number: 20060024852
    Abstract: Disclosed is a temperature sensor for an integrated circuit having at least one field effect transistor (FET) having a polysilicon gate, in which a current and a voltage is supplied to the polysilicon gate, changes in the current and the voltage of the polysilicon gate are monitored, wherein the polysilicon gate of the at least one FET is electrically isolated from other components of the integrated circuit, and the changes in the current or voltage are used to calculate a change in resistance of the polysilicon gate, and the change in resistance of the polysilicon gate is used to calculate a temperature change within the integrated circuit.
    Type: Application
    Filed: July 27, 2004
    Publication date: February 2, 2006
    Inventors: Rajiv Joshi, Sukhvinder Kang