Patents by Inventor Nirmal Ratnakumar

Nirmal Ratnakumar 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: 7869279
    Abstract: A memory device including a plurality of memory cells, each with access and program PMOS transistors situated in a common N-Well formed in a P-substrate, and an n-erase pocket formed directly in the P-substrate. Each cell includes a program PMOS including gate, and first and second P+ regions formed in an N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. Each cell further comprises an access PMOS including a gate, and first and second P+ regions formed within the same n-doped well as the first and second P+ regions of the program PMOS, wherein the first P+ region is electrically connected to the second P+ region of the program PMOS, and the gate is electrically connected to a corresponding word line. Each cell further includes an n-doped erase pocket including gate, and first and second N+ regions electrically connected to a corresponding erase line, and the gate is electrically connected to the gate of the program PMOS, forming the floating gate of the cell.
    Type: Grant
    Filed: July 18, 2008
    Date of Patent: January 11, 2011
    Assignee: Maxim Integrated Products, Inc.
    Inventor: Kola Nirmal Ratnakumar
  • Patent number: 7835186
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Grant
    Filed: July 7, 2008
    Date of Patent: November 16, 2010
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Patent number: 7835184
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Grant
    Filed: September 18, 2008
    Date of Patent: November 16, 2010
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Patent number: 7791955
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Grant
    Filed: July 7, 2008
    Date of Patent: September 7, 2010
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Publication number: 20090014772
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Application
    Filed: September 18, 2008
    Publication date: January 15, 2009
    Applicant: Maxim Integrated Products, Inc.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Publication number: 20080273401
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Application
    Filed: July 7, 2008
    Publication date: November 6, 2008
    Applicant: MAXIM INTEGRATED PRODUCTS, INC.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Publication number: 20080273392
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Application
    Filed: July 7, 2008
    Publication date: November 6, 2008
    Applicant: MAXIM INTEGRATED PRODUCTS, INC.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Patent number: 7436710
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: October 14, 2008
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Publication number: 20080225601
    Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.
    Type: Application
    Filed: March 12, 2007
    Publication date: September 18, 2008
    Applicant: MAXIM INTEGRATED PRODUCTS, INC.
    Inventors: Nirmal Ratnakumar, Venkatraman Prabhakar, David Kuan-Yu Liu
  • Patent number: 6831346
    Abstract: In an embodiment of an integrated circuit structure having buried layer substrate isolation and a method for forming same, a buried layer having conductivity type opposite to that of an overlying well region is used for wells containing transistors prone to noise generation, where the wells are of the same conductivity type as the substrate. The buried layer may in some embodiments include a first portion underlying the transistor and a second portion spaced apart from and laterally surrounding the first portion. In some embodiments, the circuit may include a doped annular region of the same conductivity type as the buried layer, where the annular region contacts a portion of the buried layer and laterally surrounds the transistor. The circuit may further include metallization adapted to connect the well and annular region to opposite polarities of a power supply voltage, or in some embodiments to preclude such connection.
    Type: Grant
    Filed: May 4, 2001
    Date of Patent: December 14, 2004
    Assignee: Cypress Semiconductor Corp.
    Inventors: Gabriel Li, Kenelm G. D. Murray, Jose Arreola, Shahin Sharifzadeh, K. Nirmal Ratnakumar
  • Patent number: 6803289
    Abstract: A method for fabricating a bipolar transistor is provided. In some cases, the method may include patterning an epitaxial layer to expose one or more regions of a semiconductor topography. The method may further include depositing an intermediate layer above the exposed regions and remaining portions of the epitaxial layer. A conductive emitter structure may then be formed above and within the intermediate layer. In another embodiment, the method may include etching a first dielectric layer in alignment with a patterned base of a bipolar transistor while simultaneously etching a second dielectric layer in alignment with a patterned emitter structure of the bipolar transistor. In yet other embodiments, the method may include depositing an intermediate layer which is substantially etch resistant to a resist stripping process. In addition or alternatively, the intermediate layer may include etch characteristics that are substantially similar to a conductive layer formed above the intermediate layer.
    Type: Grant
    Filed: June 28, 2002
    Date of Patent: October 12, 2004
    Assignee: Cypress Semiconductor Corp.
    Inventors: Prabhuram Gopalan, K. Nirmal Ratnakumar, Chandrasekhar R. Gorla
  • Patent number: 6556487
    Abstract: A non-volatile SRAM cell including (i) a nonvolatile memory element, (ii) a volatile memory element coupled to the nonvolatile memory element and (iii) a gate circuit coupled to the nonvolatile memory element. The gate circuit is configured to transfer data to and from a first input/output line into the volatile memory element.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: April 29, 2003
    Assignee: Cypress Semiconductor Corp.
    Inventors: Nirmal Ratnakumar, Cathal G. Phelan, Kenelm G. D. Murray
  • Patent number: 6114724
    Abstract: An electrically erasable programmable read only memory (EEPROM) cell including a tunnel dielectric layer formed over a semiconductor substrate. The EEPROM cell may have a floating gate transistor and a select transistor. The floating gate transistor may have a floating gate formed over the tunnel dielectric and a control gate formed over the floating gate. The select transistor may have a first gate formed over the tunnel dielectric and a second gate formed over the first gate. The second gate may be electrically connected to the first gate.
    Type: Grant
    Filed: March 31, 1998
    Date of Patent: September 5, 2000
    Assignee: Cypress Semiconductor Corporation
    Inventor: K. Nirmal Ratnakumar
  • Patent number: 5986932
    Abstract: The state of a memory cell is stored by selectively imbalancing threshold voltages of storage elements of the memory cell. The threshold voltages may be selectively imbalanced by pulsing the supply voltage for the memory cell from an operating voltage level to a programming voltage level. This may be accomplished by raising the supply voltage from the operating voltage level to the programming voltage level for a period of time sufficient to store the state of the memory cell by monitoring the leakage current from the programming voltage level such that it just falls below a preestablished limit. Alternatively, the supply voltage may be repeatedly toggled between the operating voltage level and the programming voltage level for fixed time intervals until the state of the memory cell is stored. The number of toggling operations may be determined by monitoring the leakage current such that it just falls exceeds a predetermined limit.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: November 16, 1999
    Assignee: Cypress Semiconductor Corp.
    Inventors: K. Nirmal Ratnakumar, Frederick B. Jenne
  • Patent number: 5959889
    Abstract: A counter-bias scheme to reduce or eliminate charge gain in a single-poly or double-poly electrically erasable (E.sup.2) cell having separate program and read transistors which may be configured as a 6-wire cell includes applying a counter-bias voltage to the drain of a program select transistor of the E.sup.2 cell during a read operation. The counter-bias voltage may be approximately equal to a voltage on the floating gate of the cell during the read operation. The present scheme reduces the threshold voltage shifts which may otherwise be experienced in the cell during continuous read operations. In particular, the counter-bias voltage acts to reduce the electric field across the tunnel oxide of the program select transistor, thus reducing the charge gain on the floating gate.
    Type: Grant
    Filed: December 29, 1997
    Date of Patent: September 28, 1999
    Assignee: Cypress Semiconductor Corp.
    Inventor: K. Nirmal Ratnakumar