Patents by Inventor Riichiro Takemura

Riichiro Takemura 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: 8546783
    Abstract: A semiconductor device and a method of manufacturing the same with easy formation of a phase change film is realized, realizing high integration and using a phase change film as a memory element. Between a MISFET of a region forming one memory cell and an adjoining MISFET, each MISFET source adjoins in the front surface of an insulating semiconductor substrate. A multi-layer structure of a phase change film and electric conduction film of specific resistance lower than the specific resistance is formed in plan view of the front surface of a semiconductor substrate ranging over each source of both MISFETs, and a plug is stacked thereon. The multi-layer structure functions as a wiring extending and existing in parallel on the surface of the semiconductor substrate, and an electric conduction film sends current in a parallel direction on the surface of the semiconductor substrate.
    Type: Grant
    Filed: July 3, 2012
    Date of Patent: October 1, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Masahiro Moniwa, Nozomu Matsuzaki, Riichiro Takemura
  • Publication number: 20130105760
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Application
    Filed: December 19, 2012
    Publication date: May 2, 2013
    Applicant: Renesas Electronics Corporation
    Inventors: Riichiro TAKEMURA, Kenzo KUROTSUCHI, Takayuki KAWAHARA
  • Patent number: 8427864
    Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: April 23, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
  • Publication number: 20130051134
    Abstract: The disclosed semiconductor recording device achieves multi-valued reading and writing using a spin-injection magnetization-reversal tunneling magnetoresistive element (TMR element). A first current that has at least the same value as that of the element requiring the highest current to reverse the magnetization thereof among a plurality of TMR elements is, in the direction that causes reversal to either a parallel state or an anti-parallel state, applied to a memory cell having the plurality of TMR elements, and then a second current which is in the reverse direction from the first current and of which only the value needed to reverse the magnetoresistance state of at least one TMR element excluding the element requiring the maximum current among the plurality of TMR elements is applied to each, and multi-valued writing is performed.
    Type: Application
    Filed: April 5, 2011
    Publication date: February 28, 2013
    Inventors: Takayuki Kawahara, Riichiro Takemura, Takashi Ishigaki, Kiyoo Itoh
  • Publication number: 20130044537
    Abstract: There is provided a magnetic memory with using a magnetoresistive effect element of a spin-injection magnetization reversal type, in which a multi-value operation is possible and whose manufacturing and operation are simple. A preferred aim of this is solved by providing two or more magnetoresistive effect elements which are electrically connected in series to each other and by selecting one of the series-connected elements depending on a direction of a current carried in the series-connected elements, a magnitude thereof, and an order of the current thereof for performing the writing operation. For example, it is solved by differentiating plane area sizes of the respective magnetoresistive effect elements which have the same film structure from each other so as to differentiate resistance change amounts caused by respective magnetization reversal and threshold current values required for respective magnetization reversal from each other.
    Type: Application
    Filed: January 13, 2011
    Publication date: February 21, 2013
    Inventors: Takashi Ishigaki, Takayuki Kawahara, Riichiro Takemura, Kazuo Ono, Kenchi Ito
  • Publication number: 20130033928
    Abstract: Since a nonvolatile RAM allows random reading and writing operations, an erasing mode is unnecessary. From the system side, however, it is desirable to have the erasing mode because of its nonvolatile characteristic. Moreover, the erasing operation is desirably carried out at high speed with low power consumption. Therefore, memory cell arrays COA and DTA containing a plurality of memory cells MC each having a magnetoresistive element are provided, a series of data is written to the memory cell arrays COA and DTA, and at the time of erasing, an erasing operation is carried out by writing predetermined data only to the memory cell array COA.
    Type: Application
    Filed: February 2, 2010
    Publication date: February 7, 2013
    Inventors: Takayuki Kawahara, Riichiro Takemura, Kazuo Ono, Nobuaki Kohinata
  • Patent number: 8363464
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Grant
    Filed: June 20, 2012
    Date of Patent: January 29, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Riichiro Takemura, Kenzo Kurotsuchi, Takayuki Kawahara
  • Patent number: 8319204
    Abstract: A recording layer 52 made of a chalcogenide material which stores a high-resistance state of a high electrical resistance value and a low-resistance state of a low electrical resistance value is used as a memory element RM in a memory cell region, and it is formed so that a concentration of Ga or In of a first layer 52a positioned on a lower electrode TP side of the recording layer 52 is higher than the corresponding concentration of a second layer 52b positioned on an upper electrode 53 side. For example, the recording layer is formed so that a content of Ga or In of the second layer is 5 atomic % or more smaller than that of the first layer. Also, a circuit which can reverse the voltage polarity between the upper electrode and the lower electrode in a set operation and a reset operation is provided.
    Type: Grant
    Filed: July 21, 2006
    Date of Patent: November 27, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Motoyasu Terao, Satoru Hanzawa, Takahiro Morikawa, Kenzo Kurotsuchi, Riichiro Takemura, Norikatsu Takaura, Nozomu Matsuzaki
  • Publication number: 20120286225
    Abstract: A semiconductor device and a method of manufacturing the same with easy formation of a phase change film is realized, realizing high integration and using a phase change film as a memory element. Between a MISFET of a region forming one memory cell and an adjoining MISFET, each MISFET source adjoins in the front surface of an insulating semiconductor substrate. A multi-layer structure of a phase change film and electric conduction film of specific resistance lower than the specific resistance is formed in plan view of the front surface of a semiconductor substrate ranging over each source of both MISFETs, and a plug is stacked thereon. The multi-layer structure functions as a wiring extending and existing in parallel on the surface of the semiconductor substrate, and an electric conduction film sends current in a parallel direction on the surface of the semiconductor substrate.
    Type: Application
    Filed: July 3, 2012
    Publication date: November 15, 2012
    Applicant: Renesas Electronics Corporation
    Inventors: Masahiro Moniwa, Nozomu Matsuzaki, Riichiro Takemura
  • Publication number: 20120256157
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Application
    Filed: June 20, 2012
    Publication date: October 11, 2012
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Riichiro TAKEMURA, Kenzo KUROTSUCHI, Takayuki KAWAHARA
  • Publication number: 20120249180
    Abstract: A device is disclosed herein, which may be used a level-shift circuit. The device includes first, second and third power supply lines supplied respectively with first, second and third power voltages that are different from one another, first and second input terminals and an output terminal, an output circuit coupled to the first power supply line, the first and second input terminals and the output terminal, a first inverter including an input node coupled to the first input terminal and an output node coupled to the second input terminal, a first transistor coupled in series to the first inverter between the second and third power supply lines, the fifth transistor being rendered non-conductive to deactivate the first inverter, and a control circuit configured to prevent the output terminal from being brought into an electrical floating state during deactivation of the first inverter.
    Type: Application
    Filed: March 23, 2012
    Publication date: October 4, 2012
    Inventors: Takamasa SUZUKI, Akira Kotabe, Tomonori Sekiguchi, Riichiro Takemura
  • Patent number: 8232543
    Abstract: A semiconductor device and a method of manufacturing the same with easy formation of a phase change film is realized, realizing high integration at the time of using a phase change film as a memory element. Between MISFET of the region which forms one memory cell, and MISFET which adjoined it, each source of MISFET adjoins in the front surface of a semiconductor substrate, insulating. And the multi-layer structure of a phase change film, and the electric conduction film of specific resistance lower than the specific resistance is formed in the plan view of the front surface of a semiconductor substrate ranging over each source of both MISFET, and a plug and a plug stacked on it. The multi-layer structure functions as a wiring extending and existing in parallel on the surface of a semiconductor substrate, and an electric conduction film sends the current of a parallel direction on the surface of a semiconductor substrate.
    Type: Grant
    Filed: January 10, 2011
    Date of Patent: July 31, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Masahiro Moniwa, Nozomu Matsuzaki, Riichiro Takemura
  • Patent number: 8228724
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Grant
    Filed: January 6, 2012
    Date of Patent: July 24, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Riichiro Takemura, Kenzo Kurotsuchi, Takayuki Kawahara
  • Patent number: 8199596
    Abstract: A sense amplifier is constructed to reduce the occurrence of malfunctions in a memory read operation, and thus degraded chip yield, due to increased offset of the sense amplifier with further sealing down. The sense amplifier circuit is constructed with a plurality of pull-down circuits and a pull-up circuit, and a transistor in one of the plurality of pull-down circuits has a constant such as a channel length or a channel width larger than that of a transistor in another pull-down circuit. The pull-down circuit with a larger constant of a transistor is first activated, and then, the other pull-down circuit and the pull-up circuit are activated to perform the read operation.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: June 12, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Satoru Akiyama, Riichiro Takemura, Takayuki Kawahara, Tomonori Sekiguchi
  • Publication number: 20120097912
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Application
    Filed: January 6, 2012
    Publication date: April 26, 2012
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Riichiro TAKEMURA, Kenzo KUROTSUCHI, Takayuki KAWAHARA
  • Publication number: 20120092921
    Abstract: A technique for increasing rewriting current without increasing a power supply voltage and also reducing location dependency inside a memory array of a resistive state after the rewriting is provided in a resistance change memory in which the resistance value of a memory cell changes between logical values “1” and “0”. In the resistance change memory, bit lines are formed into a layered structure, the bit line select switches for connecting to the global bit line are provided at both ends of the local bit line, and a control method of the bit line select switches is changed in the writing and the reading, thereby realizing the optimum array configurations for each of them. More specifically, in the writing and the reading, two current paths are provided in parallel by turning ON the bit line select switches simultaneously.
    Type: Application
    Filed: December 19, 2011
    Publication date: April 19, 2012
    Inventors: Kazuo ONO, Riichiro Takemura, Tomonori Sekiguchi
  • Publication number: 20120081952
    Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
    Type: Application
    Filed: June 2, 2010
    Publication date: April 5, 2012
    Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
  • Patent number: 8116128
    Abstract: For example, one memory cell is configured using two memory cell transistors and one phase change element by disposing a plurality of diffusion layers in parallel to a bit-line, disposing gates between the diffusion layers so as to cross the bit-line, disposing bit-line contacts and source contacts alternately to the plurality of diffusion layers arranged in a bit-line direction for each diffusion layer, and providing a phase change element on the source contact. Also, the phase change element can be provided on the bit-line contact instead of the source contact. By this means, for example, increase in drivability of the memory cell transistors and reduction in area can be realized.
    Type: Grant
    Filed: May 5, 2010
    Date of Patent: February 14, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Riichiro Takemura, Kenzo Kurotsuchi, Takayuki Kawahara
  • Patent number: 8102695
    Abstract: A technique for increasing rewriting current without increasing a power supply voltage and also reducing location dependency inside a memory array of a resistive state after the rewriting is provided in a resistance change memory in which the resistance value of a memory cell changes between logical values “1” and “0”. In the resistance change memory, bit lines are formed into a layered structure, the bit line select switches for connecting to the global bit line are provided at both ends of the local bit line, and a control method of the bit line select switches is changed in the writing and the reading, thereby realizing the optimum array configurations for each of them. More specifically, in the writing and the reading, two current paths are provided in parallel by turning ON the bit line select switches simultaneously.
    Type: Grant
    Filed: April 25, 2009
    Date of Patent: January 24, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Kazuo Ono, Riichiro Takemura, Tomonori Sekiguchi
  • Patent number: 8035147
    Abstract: A high-speed and low-voltage DRAM memory cell capable of operating at 1 V or less and an array peripheral circuit are provided. A DRAM cell is comprised of a memory cell transistor and planar capacitor which utilize a FD-SOI MOST structure. Since there is no junction leakage current, loss of stored charge is eliminated, and the low-voltage operation can be realized. Further, a gate and a well in a cross-coupled type sense amplifier using FD-SOI MOSTs are connected. By this means, a threshold value dynamically changes and high-speed sensing operation can be realized.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: October 11, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Kiyoo Itoh, Riichiro Takemura