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).

  • Patent number: 7119578
    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: Grant
    Filed: November 24, 2003
    Date of Patent: October 10, 2006
    Assignee: International Business Machines Corp.
    Inventors: Anthony Correale, Jr., Rajiv V. Joshi, David S. Kung, Zhigang Pan, Ruchir Puri
  • Patent number: 7113006
    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: Grant
    Filed: February 25, 2005
    Date of Patent: September 26, 2006
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi, Jack Allan Mandelman
  • Patent number: 7092280
    Abstract: A CMOS static random access memory (SRAM) array with dynamically asymmetric cells, an integrated circuit (IC) chip including the SRAM and a method of accessing data in the SRAM. Each column of cells is connected to a pair of column supply lines supplying power to the column. During each SRAM access, a higher voltage is applied to one column supply line in each pair of the columns being accessed to unbalance cells in the columns being accessed. Unbalanced cells become asymmetric during accesses and the supply imbalance favors the data state being written/read.
    Type: Grant
    Filed: November 22, 2004
    Date of Patent: August 15, 2006
    Assignee: International Business Machines Corp.
    Inventor: Rajiv V. Joshi
  • Patent number: 7093171
    Abstract: A row redundancy system is provided for replacing faulty wordlines of a memory array having a plurality of banks. The row redundancy system includes a remote fuse bay storing at least one faulty address corresponding to a faulty wordline of the memory array; a row fuse array for storing row fuse information corresponding to at least one bank of the memory array; and a copy logic module for copying at least one faulty address stored in the remote fuse bay into the row fuse array; the copy logic module is programmed to copy the at least one faulty address into the row fuse information stored in the row fuse array corresponding to a predetermined number of banks in accordance with a selectable repair field size.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: August 15, 2006
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Gregory J. Fredeman, Rajiv V. Joshi, Toshiaki Kirihata
  • Patent number: 7085798
    Abstract: A 64-bit adder implemented in partially depleted silicon on insulator technology and having two levels of lookahead uses a dynamic eight-bit carry module containing a differential pass-gate evaluation tree employing a chain of source followers that feeds a sense amplifier, thereby obtaining benefits from high initial drive, low variation in body voltage, resulting in low variation in history-dependent delay, reduced noise sensitivity and noise-based delay.
    Type: Grant
    Filed: June 10, 2002
    Date of Patent: August 1, 2006
    Assignee: International Business Machines Corporation
    Inventors: Jae-Joon Kim, Ching-Te K. Chuang, Rajiv V. Joshi, Kaushik Roy
  • Patent number: 7057866
    Abstract: An integrated circuit system having a plurality of macros is provided. The integrated circuit system includes an external voltage supply input configured for supplying an external voltage to the integrated circuit; and a plurality of internal voltage supply generators, each of the plurality of internal voltage supply generators being connected to a respective macro of the plurality of macros and configured for receiving the external voltage via the external voltage supply input for generating an internal voltage supply for operating its respective macro. Each of the plurality of internal voltage supply generators includes circuitry for generating the internal voltage supply and circuitry for disconnecting at least a portion of its respective macro. The integrated circuit system can be applied to a semiconductor chip to save active or stand-by power. It can also be used to disconnect a defective portion of the chip and optionally replace it with a non-defective portion of the chip.
    Type: Grant
    Filed: August 14, 2001
    Date of Patent: June 6, 2006
    Assignee: International Business Machines Corp.
    Inventors: Louis L. Hsu, Rajiv V. Joshi, Chorng-Lii Hwang, Toshiaki K. Kirihata, Paul C. Parries
  • Patent number: 7018916
    Abstract: A method (and structure) that selectively forms a dielectric chamber on an electronic device by forming a dummy structure over a semiconductor substrate, depositing a dielectric layer over the dummy structure, forming an opening through the dielectric layer to the dummy structure, and removing the dummy structure to form the dielectric chamber.
    Type: Grant
    Filed: November 3, 2003
    Date of Patent: March 28, 2006
    Assignee: International Business Machines Corporation
    Inventors: George C. Feng, Louis L. Hsu, Rajiv V. Joshi
  • Patent number: 7006403
    Abstract: Bit and write decode/drivers, a random access memory (RAM) including the decode/drivers and an IC with a static RAM (SRAM) including the decode/drivers. The decode/drivers are clocked by a local clock and each produce access pulses wider than corresponding clock pulses. The bit decode/driver produces bit select pulses that are wider than a word select pulse and the write decode/driver produces write pulses that are wider than the bit select pulses for stable self timed RAM write accesses.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: February 28, 2006
    Assignee: International Business Machines Corp.
    Inventors: Rajiv V. Joshi, Arthur D. Tuminaro
  • Patent number: 6992917
    Abstract: An integrated circuit (IC), random access memory on an IC and method of neutralizing device floating body effects. A floating body effect monitor monitors circuit/array activity and selectively provides an indication of floating body effect manifestation from inactivity, including the lapse of time since the most recent activity or memory access. A pulse generator generates a neutralization pulse in response to an indication of inactivity. A neutralization pulse distribution circuit passes the neutralization pulse to blocks in the circuit path or to array cells.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: January 31, 2006
    Assignee: International Business Machines Corporation
    Inventors: William R. Dachtera, Louis L. Hsu, Rajiv V. Joshi
  • Patent number: 6990038
    Abstract: A multi-port (e.g., two port) CMOS static random access memory (SRAM) with a local clock driver generating clocks for boundary latches. Local clocks select between address inputs clocked into the boundary latches. A read clock selects and latches a read address in the boundary latches. A second clock latches write addresses and, when appropriate, test data addresses.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: January 24, 2006
    Assignee: International Business Machines Corp.
    Inventors: Yuen H. Chan, Timothy J. Charest, Rajiv V. Joshi, Rolf Sautter
  • Patent number: 6964908
    Abstract: A metal-insulator-metal (MIM) capacitor including a metal layer, an insulating layer formed on the metal layer, at least a first opening and at least a second opening formed in the first insulating layer, a dielectric layer formed in the first opening, a conductive material deposited in the first and second openings, and a first metal plate formed over the first opening and a second metal plate formed over the second opening. A method for fabricating the MIM capacitor, includes forming the first metal layer, forming the insulating layer on the first metal layer, forming at least the first opening and at least the second opening in the first insulating layer, depositing a mask over the second opening, forming the dielectric layer in the first opening, removing the mask, depositing the conductive material in the first and second openings, and depositing a second metal layer over the first and second openings.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: November 15, 2005
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi, Chun-Yung Sung
  • Patent number: 6952113
    Abstract: A multi-threshold integrated circuit (IC) with reduced subthreshold leakage and method of reducing leakage. Selectable supply switching devices (NFETs and/or PFETs) between a logic circuit and supply connections (Vdd and Ground) for the circuit have higher thresholds than normal circuit devices. Some devices may have thresholds lowered when the supply switching devices are on. Header/footer devices with further higher threshold voltages and widths may be used to further increase off resistance and maintain/reduce on resistance. Alternatively, high threshold devices may be stacked to further reduce leakage to a point achieved for an even higher threshold. Intermediate supply connects at the devices may have decoupling capacitance and devices may be tapered for optimum stack height and an optimum taper ratio to minimize circuit leakage and circuit delay.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: October 4, 2005
    Assignee: International Business Machines Corp.
    Inventors: Richard B. Brown, Ching-Te K. Chuang, Peter W. Cook, Koushik K. Das, Rajiv V. Joshi
  • Patent number: 6934182
    Abstract: Methods for designing a 6T SRAM cell having greater stability and/or a smaller cell size are provided. A 6T SRAM cell has a pair access transistors (NFETs), a pair of pull-up transistors (PFETs), and a pair of pull-down transistors (NFETs), wherein the access transistors have a higher threshold voltage than the pull-down transistors, which enables the SRAM cell to effectively maintain a logic “0” during access of the cell thereby increasing the stability of the cell, especially for cells during “half select.” Further, a channel width of a pull-down transistor can be reduced thereby decreasing the size of a high performance six transistor SRAM cell without effecting cell the stability during access. And, by decreasing the cell size, the overall design layout of a chip may also be decreased.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: August 23, 2005
    Assignee: International Business Machines Corporation
    Inventors: Yuen H. Chan, Louis L. Hsu, Rajiv V. Joshi, Robert Chi-Foon Wong
  • Patent number: 6921982
    Abstract: A channel 16 of a FinFET 10 has a channel core 24 and a channel envelope 32, each made from a semiconductor material defining a different lattice structure to exploit strained silicon properties. A gate is coupled to the channel envelope through a gate dielectric. Exemplary materials are Si and SixGe1-x, wherein 78<x<92. The channel core 24 has a top surface 26 of width wc and an upstanding surface 28, 30 of height hc, preferably oriented 90° to one another. The channel envelope 32 is in contact with the top 26 and upstanding surfaces 28, 30 so that the area of interface is increased as compared to contact only along the top surface 26, improving electrical conductivity and gate 18 control over the channel 16. The height hc can be tailored to enable a smaller scale FET 10 within a stabilized SRAM. Various methods of making the channel 16 are disclosed, including a mask and etch method, a handle wafer/carrier wafer method, and a shallow trench method.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: July 26, 2005
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V Joshi, Richard Q Williams
  • Patent number: 6920061
    Abstract: Loadless 4T SRAM cells, and methods for operating such SRAM cells, which can provide highly integrated semiconductor memory devices while providing increased performance with respect to data stability and increased I/O speed for data access operations. A loadless 4T SRAM cell comprises a pair of access transistors and a pair of pull-down transistors, all of which are implemented as N-channel transistors (NFETs or NMOSFETS). The access transistors have lower threshold voltages than the pull-down transistors, which enables the SRAM cell to effectively maintain a logic “1” potential during standby. The pull-down transistors have larger channel widths as compared to the access transistors, which enables the SRAM cell to effectively maintain a logic “0” potential at a given storage node during a read operation.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: July 19, 2005
    Assignee: International Business Machines Corporation
    Inventors: Azeez Bhavnagarwala, Rajiv V. Joshi, Stephen V. Kosonocky
  • Patent number: 6906354
    Abstract: A T-RAM array having a plurality of T-RAM cells is presented where each T-RAM cell has dual devices. Each T-RAM cell is planar and has a buried vertical thyristor and a horizontally stacked pseudo-TFT transfer gate. The buried vertical thyristor is located beneath the horizontally stacked pseudo-TFT transfer gate. A method is also presented for fabricating the T-RAM array having the buried vertical thyristors, the horizontally stacked pseudo-TFT transfer gates and the planar cell structure.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: June 14, 2005
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi, Fariborz Assaderaghi
  • Patent number: 6876250
    Abstract: A combined low-voltage, low-power band-gap reference and temperature sensor circuit is provided for providing a band-gap reference parameter and for sensing the temperature of a chip, such as an eDRAM memory unit or CPU chip, using the band-gap reference parameter. The combined sensor circuit is insensitive to supply voltage and a variation in the chip temperature. The power consumption of both circuits, i.e., the band-gap reference and the temperature sensor circuits, encompassing the combined sensor circuit is less than one ?W. The combined sensor circuit can be used to monitor local or global chip temperature. The result can be used to (1) regulate DRAM array refresh cycle time, e.g., the higher the temperature, the shorter the refresh cycle time, (2) to activate an on-chip or off-chip cooling or heating device to regulate the chip temperature, (3) to adjust internally generated voltage level, and (4) to adjust the CPU (or microprocessor) clock rate, i.e., frequency, so that the chip will not overheat.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: April 5, 2005
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi, Russell J. Houghton
  • Patent number: 6876557
    Abstract: A unified SRAM cache system is provided incorporated several SRAM macros of an embedded DRAM (eDRAM) system and their functions. Each incorporated SRAM macro can be independently accessed without interfering with the other incorporated SRAM macros within the unified SRAM cache system. The incorporated SRAM macros share a single set of support circuits, such as row decoders, bank decoders, sense amplifiers, wordline drivers, bank pre-decoders, row pre-decoders, I/O drivers, multiplexer switch circuits, and data buses, without compromising the performance of the eDRAM system.
    Type: Grant
    Filed: June 12, 2001
    Date of Patent: April 5, 2005
    Assignee: IBM Corporation
    Inventors: Louis L. Hsu, Rajiv V. Joshi
  • Patent number: 6868000
    Abstract: A silicon on insulator (SOI) CMOS circuit, macro and integrated circuit (IC) chip. The chip or macro may include be an SRAM in partially depleted (PD) SOI CMOS. Most field effect transistors (FETs) do not have body contacts. FETs otherwise exhibiting a sensitivity to history effects have body contacts. The body contact for each such FET is connected to at least one other body contact. A back bias voltage may be provided to selected FETs.
    Type: Grant
    Filed: May 12, 2003
    Date of Patent: March 15, 2005
    Assignee: International Business Machines Corp.
    Inventors: Yuen H. Chan, Rajiv V. Joshi, Antonio R. Pelella
  • Patent number: 6864540
    Abstract: The invention includes a field effect transistor (FET) on an insulator layer, and integrated circuit (IC) on SOI chip including the FETs and a method of forming the IC. 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: May 21, 2004
    Date of Patent: March 8, 2005
    Assignee: International Business Machines Corp.
    Inventors: Rama Divakaruni, Louis C. Hsu, Rajiv V. Joshi, Carl J. Radens