Patents by Inventor Stephen Casper

Stephen Casper 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: 20060280011
    Abstract: Voltage coupling/decoupling devices are provided within DRAM devices for improving the bias sensing of sense amplifiers and thus the refresh performance. The voltage coupling/decoupling devices couple or decouple bias voltage from corresponding digit lines coupled to the sense amplifiers. By coupling and decoupling voltage from the digit lines, the time interval between refresh operations can be increased.
    Type: Application
    Filed: June 13, 2006
    Publication date: December 14, 2006
    Inventors: David McElroy, Stephen Casper
  • Publication number: 20060120193
    Abstract: A dynamic random access memory (“DRAM”) device is operable in either a normal refresh mode or a static refresh mode, such as a self-refresh mode. A cell plate voltage selector couples a voltage of one-half the supply voltage to the cell plate of a DRAM array in a normal refresh mode and in the static refresh mode when memory cells are being refreshed. In between refresh bursts in the static refresh mode, the cell plate voltage selector couples a reduced voltage to the cell plate. This reduces the voltage reduces the voltage across diode junctions formed between the source/drain of respective access transistor and the substrate. The reduced voltage reduces the discharge current flowing from memory cells capacitors, thereby allowing a reduction in the required refresh rate and a consequential reduction in power consumption.
    Type: Application
    Filed: December 3, 2004
    Publication date: June 8, 2006
    Inventor: Stephen Casper
  • Publication number: 20050276145
    Abstract: Disclosed herein are exemplary embodiments of an improved differential input buffer for signal) and a reference signal, and provides a differential amplifier output representative of a comparison of the magnitude of the input signals. As improved, input buffer circuitry comprises a pull up stage to pull up the voltage of the differential amplifier output slightly higher during an output low condition. The pull up stage is preferably, but not necessarily, activated only during a problematic condition, such as when both input signals to the differential amplifier are low. By pulling up the output, the input buffer circuit enjoys improved margin, and is able to reliably signal a low power condition even when both inputs are low.
    Type: Application
    Filed: June 10, 2004
    Publication date: December 15, 2005
    Inventors: Stephen Casper, Scott Van De Graaff
  • Publication number: 20050018493
    Abstract: A sense circuit for reading a resistance level of a programmable conductor random access memory (PCRAM) cell is provided. A voltage potential difference is introduced across a PCRAM cell by activating an access transistor from a raised rowline voltage. Both a digit line and a digit complement reference line are precharged to a first predetermined voltage. The cell being sensed has the precharged voltage discharged through the resistance of the programmable conductor memory element of the PCRAM cell. A comparison is made of the voltage read at the digit line and at the reference conductor. If the voltage at the digit line is greater than the reference voltage, the cell is read as a high resistance value (e.g., logic HIGH); however, if the voltage measured at the digit line is lower than that of the reference voltage, the cell is read as a low resistance value (e.g., logic LOW).
    Type: Application
    Filed: August 16, 2004
    Publication date: January 27, 2005
    Inventors: Stephen Casper, Kevin Duesman, Glen Hush
  • Patent number: 6787400
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: September 7, 2004
    Assignee: Micron Technology, Inc.
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Publication number: 20030173622
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Application
    Filed: January 16, 2003
    Publication date: September 18, 2003
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Patent number: 6593218
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: July 15, 2003
    Assignee: Micron Technology, Inc.
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Patent number: 6576960
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: June 10, 2003
    Assignee: Micron Technology, Inc.
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Publication number: 20020094627
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Application
    Filed: March 11, 2002
    Publication date: July 18, 2002
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Patent number: 6365937
    Abstract: An electrostatic discharge protection device for integrated circuit is formed in a substrate and contains pad contact, rail contact and a deep oxide in a trench in the substrate which isolates pad and rail contacts. The substrate is doped with a first dopant type with a first concentration. A second dopant type in a first inner and a first outer region forms the pad contact; both regions are formed on the substrate. The first inner region is doped higher than the first outer region. Similarly a second dopant type in a second inner and a second outer region forms the rail contact; both regions are formed on the substrate. The second inner region is doped higher than the second outer region. Buried layers are formed of the first dopant type in a second concentration under the pad and rail contacts and under the deep oxide.
    Type: Grant
    Filed: May 12, 1999
    Date of Patent: April 2, 2002
    Assignee: Micron Technology, Inc.
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Patent number: 6355508
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: March 12, 2002
    Assignee: Micron Technology, Inc.
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman
  • Publication number: 20020028522
    Abstract: An electrostatic discharge protection device is formed in a substrate and contains a drain area of a first dopant concentration abutting an extended drain area having a dopant concentration lower than the first dopant concentration. Similarly, a highly doped source area abuts a lower doped source extension area. The source and drain are laterally bounded by oxide regions and covered by an insulation layer. The areas of lower doping prevent charge crowding during an electrostatic discharge event by resistively forcing current though the nearly planer bottom surface of the drain, a rather than the curved drain extension. In addition, a highly doped buried layer can abut an area of a graded doping level. By adjusting the doping levels of the graded areas and the buried layers, the substrate breakdown voltage is pre-selected.
    Type: Application
    Filed: August 9, 2001
    Publication date: March 7, 2002
    Inventors: Stephen R. Porter, Manny K. Ma, Stephen Casper, Kevin Duesman