Patents by Inventor Kazuhiko Kajigaya

Kazuhiko Kajigaya 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: 8624313
    Abstract: A semiconductor device includes a semiconductor substrate, a non-volatile semiconductor memory element formed over the semiconductor substrate, including a variable resistance element including a laminate comprising a first electrode, a variable resistance layer, and a second electrode, and a volatile semiconductor memory element formed over the semiconductor substrate, including a capacitance element including a laminate comprising a third electrode, a dielectric layer including a same material as the variable resistance layer, and a fourth electrode.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: January 7, 2014
    Inventor: Kazuhiko Kajigaya
  • Publication number: 20140003116
    Abstract: A semiconductor device includes first and second global bit lines; first, second, third and fourth sense node; a first sense switch coupled between the first sense node and the first global bit line; a second sense switch coupled between the second sense node and the second global bit line; a third sense switch coupled between the third sense node and the first global bit line; a fourth sense switch coupled between the fourth sense node and the second global bit line; a first sense amplifier including a first terminal coupled to the first sense node and a second terminal coupled to the second sense node; a second sense amplifier including a third terminal coupled to the third sense node and a fourth terminal coupled to the fourth sense node. The first, second, third and fourth terminals respectively have first, second, third and fourth parasitic capacitances substantially equal in capacitance value.
    Type: Application
    Filed: September 5, 2013
    Publication date: January 2, 2014
    Applicant: Elpida Memory, Inc.
    Inventors: Takenori SATO, Kazuhiko KAJIGAYA, Yoshimitsu YANAGAWA, Tomonori SEKIGUCHI, Akira KOTABE, Satoru AKIYAMA
  • Patent number: 8621135
    Abstract: A semiconductor memory device includes a plural number of data input/output pins, a plural number of banks, in each of which a plural number of the information data is stored, a selector and a control circuit. In a first access mode, the control circuit simultaneously accesses the multiple banks in response to a single read-out command or to a single write-in command from outside. In the first access mode, the selector coordinates a plurality of data input/output pins with the multiple banks in a predetermined relationship.
    Type: Grant
    Filed: January 10, 2011
    Date of Patent: December 31, 2013
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8611122
    Abstract: A device includes a first region including a plurality of first memory elements and a plurality of first vertical transistors, the first vertical transistors comprising a plurality of first selective transistors and a first switching transistor, each of the first selective transistors including an upper electrode coupled to a corresponding one of the first memory elements and a lower electrode, the first switching transistor including an upper electrode and a lower electrode coupled in common to the lower electrodes of the first selective transistors through a first signal line, a second region arranged to make a first line with the first region in a first direction and including a plurality of second memory elements and a plurality of second vertical transistors, the second vertical transistors comprising a plurality of second selective transistors and a second switching transistor, and a third region sandwiched between the first and the second regions.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: December 17, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya
  • Publication number: 20130328187
    Abstract: There is provided a semiconductor device which includes a plurality of first through-substrate vias that are used to supply power from a first power supply and that penetrate through a substrate structure, and a plurality of second through-substrate vias that are used to supply power from a second power supply different from the first power supply and that penetrate through a substrate structure. The semiconductor device also includes a through-substrate via string composed by the first and second through-substrate vias, in which the first through-substrate vias are located adjacent to one another and the second through-substrate vias are also located adjacent to one another. The through-substrate via string is disposed in the substrate structure for extending in a first direction.
    Type: Application
    Filed: June 10, 2013
    Publication date: December 12, 2013
    Inventors: Kazuo ONO, Riichiro TAKEMURA, Takamasa SUZUKI, Kazuhiko KAJIGAYA, Akira KOTABE, Yoshimitsu YANAGAWA
  • Patent number: 8605532
    Abstract: Disclosed herein is a semiconductor device comprising a memory cell, a local bit line coupled to the memory cell, a global bit line provided correspondingly to the local bit line, and a bit line control circuit coupled between the local bit line and the global bit line. The bit line control circuit includes a restoring circuit that is activated in a refresh mode to refresh data of the memory cell while being in electrical isolation from the global bit line.
    Type: Grant
    Filed: November 17, 2011
    Date of Patent: December 10, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Kazuhiko Kajigaya, Yasutoshi Yamada
  • Patent number: 8605476
    Abstract: A sense operation with respect to simultaneously-accessed two memory cells is performed by time division by using two sense amplifiers, and thereafter restore operations are performed simultaneously. With this arrangement, it is not necessary to provide switches in the middle of global bit lines, and no problem occurs when performing the restore operation by time division. Further, because a parasitic CR model of a first sense amplifier and that of a second sense amplifier become mutually the same, high sensitivity can be maintained.
    Type: Grant
    Filed: December 3, 2010
    Date of Patent: December 10, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Takenori Sato, Kazuhiko Kajigaya, Yoshimitsu Yanagawa, Tomonori Sekiguchi, Akira Kotabe, Satoru Akiyama
  • Publication number: 20130315018
    Abstract: A single-ended sense amplifier circuit of the invention comprises first and second MOS transistors and first and second precharge circuits. The first MOS transistor drives the bit line to a predetermined voltage and switches connection between the bit line and a sense node and the second MOS transistor whose gate is connected to the sense node amplifies the signal via the first MOS transistor. The first precharge circuit precharges the bit line to a first potential and the second precharge circuit precharges the sense node to a second potential. Before sensing operation, the bit line is driven to the predetermined voltage when the above gate voltage is controlled to decrease. The predetermined voltage is appropriately set so that a required voltage difference at the sense node between high and low levels can be obtained near a changing point between charge transfer/distributing modes.
    Type: Application
    Filed: November 13, 2012
    Publication date: November 28, 2013
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Kazuhiko Kajigaya, Soichiro YOSHIDA, Yasutoshi YAMADA
  • Patent number: 8593895
    Abstract: Disclosed herein is a semiconductor device comprising an array having a hierarchical bit line structure, global bit lines adjacent to each other, local bit lines corresponding to the global bit lines, hierarchical switches, precharge circuits precharging the global bit lines, precharge circuits precharging the local bit lines, and a control circuit. When performing a test of the array, precharge voltages for the global bit lines are set to potentials different from each other, and the control circuit controls the potentials to be applied to the local bit lines through the global bit lines and the hierarchical switches.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: November 26, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shinichi Takayama, Kazuhiko Kajigaya
  • Patent number: 8588019
    Abstract: A semiconductor device comprises a first transistor connected between a bit line and a sense node, and a second transistor amplifying a signal of the sense node. A first potential applied to a gate of the first transistor, a second potential supplied to the sense node, and a third potential supplied to the bit line are controlled so that the first potential applied to a gate of the first transistor is between the second and third potentials, the second potential is set larger than the third potential, and a predetermined potential obtained by subtracting a threshold voltage of the first transistor from the first potential is smaller than the third potential and higher than a low potential supplied to the second transistor. A potential of the bit line transitions from the third potential toward the low potential in accordance with data of a current change memory cell.
    Type: Grant
    Filed: November 2, 2011
    Date of Patent: November 19, 2013
    Assignee: Elpida Memory Inc.
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8542547
    Abstract: A semiconductor device comprises a first sense amplifier, first to third transmission lines, and first to third switches. The first and second transmission lines are connected to the first sense amplifier. The first and third switches control connections of the first to third transmission lines, and the second switch controls a connection between a fixed potential and third transmission line. When the second transmission line is not accessed, the first and third switches are brought into a non-conductive state and the second switch is brought into a conductive state, and the fixed potential is supplied to the third transmission line, thereby suppressing influence of the coupling noise between the transmission lines.
    Type: Grant
    Filed: June 8, 2011
    Date of Patent: September 24, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya
  • Publication number: 20130229870
    Abstract: A semiconductor random access memory device includes a memory cell including a resistor whose resistance varies by formation and disappearance of a filament due to an oxidation-reduction reaction of metal ions, a memory area configured to include a first memory area operable in a nonvolatile mode in which a stored content thereof is not lost by a power-off event, and a second memory area operable in a volatile mode in which the stored content thereof is lost by the power-off event, each of the first memory area and the second memory area including the plurality of the memory cells, a register circuit that stores information including a first address information indicating the first memory area, and a second address information indicating the second memory area, and a control circuit that controls the nonvolatile mode, and the volatile mode, with reference to the information stored in the register circuit.
    Type: Application
    Filed: April 12, 2013
    Publication date: September 5, 2013
    Applicant: Elpida Memory, Inc.
    Inventor: Kazuhiko KAJIGAYA
  • Publication number: 20130229857
    Abstract: A semiconductor device comprises a memory cell including a capacitor and a select transistor with a floating body structure, a bit line connected to the select transistor, a bit line control circuit, and a sense amplifier amplifying a signal read out from the memory cell. The bit line control circuit sets the bit line to a first potential during a non-access period of the memory cell, and thereafter sets the bit line to a second potential during an access period of the memory cell. Thereby, the data retention time can be prolonged by reducing leak current at a data storage node of the memory cell so that an average consumption current for the data retention can be reduced.
    Type: Application
    Filed: April 17, 2013
    Publication date: September 5, 2013
    Applicant: ELPIDA MEMORY, INC.
    Inventor: Kazuhiko KAJIGAYA
  • Patent number: 8520449
    Abstract: A semiconductor device has a hierarchical bit line structure and comprises first and second local bit lines transmitting first and second signals of first and second memory cells corresponding to a selected word line, and first and second global bit lines electrically connected to the first and second local bit lines through first and second switches, first and second sense amplifiers connected to the first and second global bit lines, and a control circuit. During a first period after the first and second memory cells are simultaneously accessed, the control circuit controls the first switch to conduction state so that the first sense amplifier amplifies the first signal and controls the second switch to non conduction state. During a second period after sensing of the first sense amplifier finishes, the control circuit controls the second switch to conduction state so that the second sense amplifier amplifies the second signal.
    Type: Grant
    Filed: September 9, 2011
    Date of Patent: August 27, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8509020
    Abstract: A data processing system includes a first semiconductor device that has a plurality of blocks each including plural data, and a second semiconductor device that has a first control circuit controlling the first semiconductor device, and the first control circuit issues a plurality of commands to communicate with the first semiconductor device in units of access units including a plurality of first definitions that define a plurality of burst lengths indicating numbers of different data, respectively, and a plurality of second definitions that define correspondences between certain elements of data among the plural data included in the blocks, respectively, and arrangement orders in the numbers of different data that constitute the burst lengths, respectively, and communicates with the first semiconductor device through the plural data in the numbers of different data according to the first and second definitions.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: August 13, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8477552
    Abstract: A semiconductor memory device comprises a memory cell array, first and second bit lines, first and second amplifiers, and a sense amplifier control circuit. An amplifying element in the first sense amplifier amplifiers the signal of the first bit line and converts it into an output current. The second bit line is selectively connected to the first bit line via the first sense amplifier. A signal voltage decision unit in the second sense amplifier determines the signal level of the second bit line being supplied with the output current. The sense amplifier control circuit controls connection between the amplifying element and the unit in accordance with a determination timing, which switches the above connection from a connected state to a disconnected state at a first timing in a normal operation and switches in the same manner at a delayed second timing in a refresh operation.
    Type: Grant
    Filed: December 17, 2012
    Date of Patent: July 2, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Kazuhiko Kajigaya, Soichiro Yoshida
  • Patent number: 8472272
    Abstract: A semiconductor device of the invention comprise a memory cell array configured with hierarchical local bit lines and global bit lines, in which there are provide local bit lines, global bit lines, switches controlling a connection between the global bit lines, sense amplifiers, and a control circuit controlling the switches. In a first period, each sense amplifier amplifies a signal of one of adjacent global bit lines, and in a second period, each sense amplifier amplifies a signal of the other thereof. Accordingly, coupling between the global bit lines can be suppressed.
    Type: Grant
    Filed: November 2, 2011
    Date of Patent: June 25, 2013
    Assignee: Elpida Memory Inc.
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8467217
    Abstract: The semiconductor device comprises first and second memory cells, first and second bit lines connected to the first/second memory cells, first and second amplifiers connected to the second bit line, a local input/output line commonly connected to the first/second amplifiers, first and second local column switches connected between the first/second amplifiers and the local input/output line, a second local column switch connected between the second amplifier and the local input/output line, a column select line, a first global column switch connected between the column select line and the first local column switch and controlling a connection therebetween in response to a first select signal, and a second global column switch connected between the column select line and the second local column switch and controlling a connection therebetween in response to a first select signal.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: June 18, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shinichi Takayama, Kazuhiko Kajigaya, Akira Kotabe, Satoru Akiyama, Tomonori Sekiguchi
  • Patent number: 8441840
    Abstract: A semiconductor device comprises a memory cell including a capacitor and a select transistor with a floating body structure, a bit line connected to the select transistor, a bit line control circuit, and a sense amplifier amplifying a signal read out from the memory cell. The bit line control circuit sets the bit line to a first potential during a non-access period of the memory cell, and thereafter sets the bit line to a second potential during an access period of the memory cell. Thereby, the data retention time can be prolonged by reducing leak current at a data storage node of the memory cell so that an average consumption current for the data retention can be reduced.
    Type: Grant
    Filed: January 13, 2011
    Date of Patent: May 14, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya
  • Patent number: 8437188
    Abstract: A nonvolatile RAM for reading and writing data in a random manner includes a memory area configured by a plurality of memory cells suited to a nonvolatile-mode write operation, in which the stored content thereof is not lost irrespective of a power-off event, and a volatile-mode write operation, in which the stored content thereof is lost in the power-off event. A register designates a first portion of the memory area adapted to the nonvolatile-mode write operation regarding fixed data such as program codes and a second portion of the memory area serving as a work area adapted to the volatile-mode write operation. A control circuit performs the nonvolatile-mode write operation on the first portion of the memory area while performing the volatile-mode write operation on the second portion of the memory area.
    Type: Grant
    Filed: February 14, 2008
    Date of Patent: May 7, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Kazuhiko Kajigaya