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: 20090070716
    Abstract: A system and method for designing a circuit includes generating physics based equations to describe phenomena of a circuit component, representing physical device geometry by correlating the physical device geometry with features of a circuit component design, and integrating the physical based equations and correlated physical device geometry into a computer based model to represent aspects of behavior and geometry for the circuit component. The circuit component is modeled in the presence of variability by statistically analyzing a design space defined by a plurality of parameters in the physics based equations and the physical device geometry to optimize at least one of cost and yield to determine an optimal design point. The circuit component is provided using the optimal design point.
    Type: Application
    Filed: September 12, 2007
    Publication date: March 12, 2009
    Inventors: RAJIV V. JOSHI, ROUWAIDA KANJ, KEUNWOO KIM
  • Patent number: 7495969
    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: Grant
    Filed: January 30, 2007
    Date of Patent: February 24, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20090027983
    Abstract: A programmable precharge circuit includes a plurality of transistors. Each transistor has a different threshold voltage from other transistors of the plurality of transistors. Each transistor is configured to connect a supply voltage to a node, and the node is selectively coupled to bitlines in accordance with a memory operation. Control logic is configured to enable at least one of the plurality of transistors to provide a programmable precharge voltage to the node in accordance with a respective threshold voltage drop from the supply voltage of one of the plurality of transistors.
    Type: Application
    Filed: July 24, 2007
    Publication date: January 29, 2009
    Inventors: Rajiv V. Joshi, Rouwaida Kanj, Jayakumaran Sivagnaname
  • Patent number: 7483322
    Abstract: A ring oscillator row circuit for evaluating memory cell performance provides for circuit delay and performance measurements in an actual memory circuit environment. A ring oscillator is implemented with a row of memory cells and has outputs connected to one or more bitlines along with other memory cells that are substantially identical to the ring oscillator cells. Logic may be included for providing a fully functional memory array, so that the cells other than the ring oscillator cells can be used for storage when the ring oscillator row wordlines are disabled. One or both power supply rails of individual cross-coupled inverter stages forming static memory cells used in the ring oscillator circuit may be isolated from each other in order to introduce a voltage asymmetry so that circuit asymmetry effects on delay can be evaluated.
    Type: Grant
    Filed: December 22, 2007
    Date of Patent: January 27, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Qiuyi Ye, Yuen H. Chan, Anirudh Devgan
  • Publication number: 20090023286
    Abstract: Dielectric interconnect structures and methods for forming the same are provided. Specifically, the present invention provides a dielectric interconnect structure having a noble metal layer (e.g., Ru, Ir, Rh, Pt, RuTa, and alloys of Ru, Ir, Rh, Pt, and RuTa) that is formed directly on a modified dielectric surface. In a typical embodiment, the modified dielectric surface is created by treating an exposed dielectric layer of the interconnect structure with a gaseous ion plasma (e.g., Ar, He, Ne, Xe, N2, H2, NH3, and N2H2). Under the present invention, the noble metal layer could be formed directly on an optional glue layer that is maintained only on vertical surfaces of any trench or via formed in the exposed dielectric layer. In addition, the noble metal layer may or may not be provided along an interface between the via and an internal metal layer.
    Type: Application
    Filed: July 16, 2008
    Publication date: January 22, 2009
    Inventors: Chih-Chao Yang, Louis C. Hsu, Rajiv V. Joshi
  • Patent number: 7470929
    Abstract: Techniques are provided for fuse/anti-fuse structures, including an inner conductor structure, an insulating layer spaced outwardly of the inner conductor structure, an outer conductor structure disposed outwardly of the insulating layer, and a cavity-defining structure that defines a cavity, with at least a portion of the cavity-defining structure being formed from at least one of the inner conductor structure, the insulating layer, and the outer conductor structure. Methods of making and programming the fuse/anti-fuse structures are also provided.
    Type: Grant
    Filed: July 24, 2006
    Date of Patent: December 30, 2008
    Assignee: International Business Machines Corporation
    Inventors: Louis C. Hsu, Rajiv V. Joshi, Jack Allan Mandelman, Chih-Chao Yang
  • Publication number: 20080319717
    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 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: August 27, 2008
    Publication date: December 25, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Rajiv V. Joshi, Anirudh Devgan
  • Publication number: 20080310246
    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: June 12, 2007
    Publication date: December 18, 2008
    Inventors: Rajiv V. Joshi, Robert Maurice Houle, Kevin A. Batson
  • Publication number: 20080309364
    Abstract: A method and circuit for measuring internal pulses includes an enable circuit configured to receive a control signal from an on-chip built-in tester to enable measurement of internal circuits. A delay chain is configured to receive a pulse signal from an on-chip circuit component. Sampling latches each include a data input coupled between adjacent delay elements of the delay chain and synchronized with the clock signal such that a transition in the pulse signal is indicated by comparing adjacent digital values in an output sequence.
    Type: Application
    Filed: June 12, 2007
    Publication date: December 18, 2008
    Inventors: Rajiv V. Joshi, Robert L. Franch, Robert Maurice Houle, Kevin A. Batson
  • Publication number: 20080290518
    Abstract: Dielectric interconnect structures and methods for forming the same are provided. Specifically, the present invention provides a dielectric interconnect structure having a noble metal layer (e.g., Ru, Ir, Rh, Pt, RuTa, and alloys of Ru, Ir, Rh, Pt, and RuTa) that is formed directly on a modified dielectric surface. In a typical embodiment, the modified dielectric surface is created by treating an exposed dielectric layer of the interconnect structure with a gaseous ion plasma (e.g., Ar, He, Ne, Xe, N2, H2, NH3, and N2H2). Under the present invention, the noble metal layer could be formed directly on an optional glue layer that is maintained only on vertical surfaces of any trench or via formed in the exposed dielectric layer. In addition, the noble metal layer may or may not be provided along an interface between the via and an internal metal layer.
    Type: Application
    Filed: August 4, 2008
    Publication date: November 27, 2008
    Inventors: Chih-Chao Yang, Louis C. Hsu, Rajiv V. Joshi
  • Publication number: 20080281570
    Abstract: A method for circuit simulation using a netlist in which a first device having an unmodeled, nonlinear behavior is modified by inserting a second device which has a nonlinear response approximating the unmodeled nonlinear behavior. The first device may be for example a first transistor and the second device may be a variable current source, in particular one whose current is modeled after a floating transistor template which represents gate leakage current of the first transistor (gate-to-source or gate-to-drain). During simulation of the circuit a parameter such as a gate-to-source voltage of the second transistor is controlled to model gate leakage. The model parameters can be a function of an effective quantum mechanical oxide thickness value of a gate of the first transistor technology.
    Type: Application
    Filed: May 10, 2007
    Publication date: November 13, 2008
    Inventors: Rajiv V. Joshi, Rouwaida N. Kanj, Ying Liu, Sani R. Nassif, Jayakumaran Sivagnaname
  • Publication number: 20080276205
    Abstract: A memory cell for interconnection with READ and WRITE word lines and READ and WRITE bit lines includes a logical storage element such as a flip-flop formed by a first inverter and a second inverter cross-coupled to the first inverter. The storage element has first and second terminals and a storage element supply voltage terminal configured for interconnection with a first supply voltage. A WRITE access device is configured to selectively interconnect the first terminal to the WRITE bit line under control of the WRITE word line, and a pair of series READ access devices are configured to ground the READ bit line when the READ word line is active and the second terminal is at a high logical level. A logical “one” can be written to the storage element when a second supply voltage, greater than the first supply voltage, is applied to the WRITE word line, substantially without the use of a complementary WRITE bit line.
    Type: Application
    Filed: July 17, 2008
    Publication date: November 6, 2008
    Applicant: International Busines Machines Corporation
    Inventors: Keunwoo Kim, Rajiv V. Joshi, Vinod Ramadurai
  • Publication number: 20080273374
    Abstract: A memory cell for interconnection with READ and WRITE word lines and READ and WRITE bit lines includes a logical storage element such as a flip-flop formed by a first inverter and a second inverter cross-coupled to the first inverter. The storage element has first and second terminals and a storage element supply voltage terminal configured for interconnection with a first supply voltage. A WRITE access device is configured to selectively interconnect the first terminal to the WRITE bit line under control of the WRITE word line, and a pair of series READ access devices are configured to ground the READ bit line when the READ word line is active and the second terminal is at a high logical level. A logical “one” can be written to the storage element when a second supply voltage, greater than the first supply voltage, is applied to the WRITE word line, substantially without the use of a complementary WRITE bit line.
    Type: Application
    Filed: July 17, 2008
    Publication date: November 6, 2008
    Applicant: International Busines Machines Corporation
    Inventors: Keunwoo Kim, Rajiv V. Joshi, Vinod Ramadurai
  • Patent number: 7447964
    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: Grant
    Filed: January 3, 2005
    Date of Patent: November 4, 2008
    Assignee: International Business Machines Corporation
    Inventors: Yuen H. Chan, Rajiv V. Joshi
  • Publication number: 20080270864
    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: July 9, 2008
    Publication date: October 30, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPERATION
    Inventors: Yuen H. Chan, Rajiv V. Joshi
  • Publication number: 20080258555
    Abstract: There is provided a circuit for managing a multi-level power supply. The circuit includes a comparator that compares a voltage level (Vs1) of a lower voltage supply bus to a voltage level (Vs2) of a higher voltage supply bus, and a switch that routes current from the lower voltage supply bus to the higher voltage supply bus if Vs2<Vs1. The comparator is powered by the lower voltage supply bus, the lower and higher voltage supply busses provide power to an apparatus that includes a plurality of p-type metal oxide semiconductor devices in a common well, and the common well is electrically connected to the higher voltage supply bus.
    Type: Application
    Filed: June 25, 2008
    Publication date: October 23, 2008
    Inventors: Rajiv V. Joshi, Louis L. Hsu
  • Patent number: 7435674
    Abstract: Dielectric interconnect structures and methods for forming the same are provided. Specifically, the present invention provides a dielectric interconnect structure having a noble metal layer (e.g., Ru, Ir, Rh, Pt, RuTa, and alloys of Ru, Ir, Rh, Pt, and RuTa) that is formed directly on a modified dielectric surface. In a typical embodiment, the modified dielectric surface is created by treating an exposed dielectric layer of the interconnect structure with a gaseous ion plasma (e.g., Ar, He, Ne, Xe, N2, H2, NH3, and N2H2). Under the present invention, the noble metal layer could be formed directly on an optional glue layer that is maintained only on vertical surfaces of any trench or via formed in the exposed dielectric layer. In addition, the noble metal layer may or may not be provided along an interface between the via and an internal metal layer.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: October 14, 2008
    Assignee: International Business Machines Corporation
    Inventors: Chih-Chao Yang, Louis C. Hsu, Rajiv V. Joshi
  • Publication number: 20080247246
    Abstract: Methods and apparatus are provided for read/write control and bit selection with false read suppression in an SRAM. According to one aspect of the invention, a bit select circuit is provided for an SRAM. The disclosed bit select circuit comprises one or more transistors controlled by a write control gate signal to prevent data from being read from one or more data cells during a write operation. The transistors can comprise, for example, a pair of gated transistors controlled by the write control gate signal. The write control gate signal prevents data from being read from one or more data cells while the write control gate signal is in a predefined state.
    Type: Application
    Filed: June 17, 2008
    Publication date: October 9, 2008
    Inventor: Rajiv V. Joshi
  • Publication number: 20080232149
    Abstract: A multi-threshold integrated circuit (IC) that may be supplied by multiple supplies, with an array of latches such as an array static random access memory (SRAM) cells and a CMOS SRAM with improved stability and reduced subthreshold leakage. Selected devices (NFETs and/or PFETs) in array cells and support logic, e.g., in the data path and in non-critical logic, are tailored for lower gate and subthreshold leakage. Normal base FETs have a base threshold and tailored FETs have a threshold above. In a multi-supply chip, circuits with tailored FETs are powered by an increased supply voltage.
    Type: Application
    Filed: June 5, 2008
    Publication date: September 25, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: YUEN H. CHAN, RAJIV V. JOSHI, DONALD W. PLASS
  • Publication number: 20080231323
    Abstract: A multi-threshold integrated circuit (IC) that may be supplied by multiple supplies, with an array of latches such as an array static random access memory (SRAM) cells and a CMOS SRAM with improved stability and reduced subthreshold leakage. Selected devices (NFETs and/or PFETs) in array cells and support logic, e.g., in the data path and in non-critical logic, are tailored for lower gate and subthreshold leakage. Normal base FETs have a base threshold and tailored FETs have a threshold above. In a multi-supply chip, circuits with tailored FETs are powered by an increased supply voltage.
    Type: Application
    Filed: April 25, 2008
    Publication date: September 25, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: YUEN H. CHAN, RAJIV V. JOSHI, DONALD W. PLASS