Patents by Inventor Takeshi Hamamoto

Takeshi Hamamoto 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: 20010052808
    Abstract: A clock generation circuit includes a clock input circuit receiving complementary external clocks to generate an internal clock, a variable delay circuit delaying the internal clock to generate an internal operation clock, a replica circuit further delaying the internal operation clock by a predetermined time to generate a return clock, a phase comparator directly comparing the phase where potential levels of external clocks cross with the phase of the return clock, and a delay control circuit adjusting the delay amount of the variable delay circuit according to a phase comparison result of the phase comparator.
    Type: Application
    Filed: February 28, 2001
    Publication date: December 20, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Kiyohiro Furutani
  • Publication number: 20010050388
    Abstract: MOS transistors are formed on island-shaped divided element regions of a silicon substrate, and provided with gate electrodes having the same widths as the element regions. Thereafter, capacitor grooves are formed at end portions of the element regions, and capacitor insulating films formed of BSTO are provided on inner walls of the capacitor grooves. Then, the capacitor grooves are filled with storage electrodes, thereby forming capacitors. Furthermore, connection conductors are formed to connect the storage electrodes and source diffusion layers of the MOS transistors. Then, word lines are formed to connect the gate electrodes of the MOS transistors, and further bit lines are formed to connect drain diffusion layers of the MOS transistors.
    Type: Application
    Filed: December 2, 1998
    Publication date: December 13, 2001
    Inventor: TAKESHI HAMAMOTO
  • Patent number: 6326658
    Abstract: A buried strap is formed after forming an SiC layer on the side surface of a trench in order to suppress the epitaxial growth of Si from the side surface (single crystal Si) of the trench to the buried strap (polycrystalline Si) without causing an increase in the contact resistance in the post process accompanied by high temperature after formation of the buried strap.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: December 4, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshitaka Tsunashima, Katsuya Okumura, Masayuki Tanaka, Shigehiko Saida, Hirofumi Inoue, Takeshi Hamamoto
  • Patent number: 6317368
    Abstract: Data are read out from sub-arrays within a memory cell array in batches. A data bus driving circuit compares the read data, and, according to the comparison result, drives the potentials of data buses with small amplitudes. A data retaining circuit retains fail information indicating the presence of a fail bit, according to the data on the data buses. The data retaining circuit responds to an externally supplied designation, and provides a pass/fail information output circuit with the fail information with large amplitude. The fail information is further output to the outside.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: November 13, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiko Taito, Takeshi Hamamoto, Tetsuo Kato
  • Publication number: 20010030898
    Abstract: A semiconductor memory device includes a pair of complementary data buses, capacitive element corresponding to an even-numbered address, an equalize circuit and amplifier, capacitive element corresponding to an odd-numbered address, and an equalize circuit and amplifier. The pair of complementary data buses continuously transfer even-numbered address data and odd-numbered address data read out from the memory cell array in an alternating manner. The equalize circuit corresponding to the odd-numbered address is operated when the amplifier corresponding to the even-numbered address operates whereas the equalize circuit corresponding to the even-numbered address is operated when the amplifier corresponding to the odd-numbered address operates.
    Type: Application
    Filed: January 30, 2001
    Publication date: October 18, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigehiro Kuge, Takeshi Hamamoto
  • Publication number: 20010030903
    Abstract: A DLL circuit includes a delay circuit for producing an output clock signal by delaying an input clock signal, and a phase comparator circuit for making a comparison between phases of the output and input clock signals. The delay circuit includes a plurality of delay units each having a unit delay amount changing in accordance with a drive potential level. The DLL circuit further includes a delay control circuit for controlling activation of the delay units in accordance with the result of phase comparison of the phase comparator circuit, and a drive potential control circuit for controlling the drive potential in accordance with the result of phase comparison of the phase comparator circuit.
    Type: Application
    Filed: February 2, 2001
    Publication date: October 18, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigehiro Kuge, Takeshi Hamamoto
  • Patent number: 6301169
    Abstract: In a set of memory cells selected by one column select line, a memory cell of at least 1 bit is connected to an internal data line that is different from the internal data line to which another memory cell in the same set is connected. An internal data line pair is connected to a data terminal. Thus, data having different logic levels can be written into adjacent memory cells even in an IO compression test mode.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: October 9, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeru Kikuda, Takeshi Hamamoto, Mikio Asakura
  • Patent number: 6262931
    Abstract: A control circuit & mode register outputs a signal responsive to each command to a VDC control circuit. The VDC control circuit outputs a signal PWRUP changing the quantity of a through current Ic of a comparator stored in a VDC in response to the command. The VDC control circuit internally generates a signal of which pulse width corresponds to a prescribed delay time, in response to input of the command. Therefore, activation of each bank may not be monitored but current consumption can be reduced by preferably controlling a power supply current while minimizing the number of delay circuits and wires.
    Type: Grant
    Filed: March 31, 2000
    Date of Patent: July 17, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Kono, Kiyohiro Furutani, Takeshi Hamamoto, Katsuyoshi Mitsui
  • Patent number: 6243320
    Abstract: A command decoder receives an externally supplied command independently of an internal clock signal, decodes the command, generates a column access mode instruction signal, and activates a column address activation signal when the internal clock signal rises. An internal column address signal generating circuit generates an internal column address signal from an externally supplied address signal according to the column address activation signal. Accordingly, the internal column address is generated at an advanced timing to enable a following column selecting operation to be started at a faster timing. A synchronous semiconductor memory device capable of performing the column selecting operation at a high speed is thus provided.
    Type: Grant
    Filed: March 11, 1999
    Date of Patent: June 5, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Zenya Kawaguchi, Motoko Hara
  • Publication number: 20010000693
    Abstract: A command decoder receives an externally supplied command independently of an internal clock signal, decodes the command, generates a column access mode instruction signal, and activates a column address activation signal when the internal clock signal uses. An internal column address signal generating circuit generates an internal column address signal from an externally supplied address signal according to the column address activation signal. Accordingly, the internal column address is generated at an advanced timing to enable a following column selecting operation to be started at a faster timing. A synchronous semiconductor memory device capable of performing the column selecting operation at a high speed is thus provided.
    Type: Application
    Filed: November 30, 2000
    Publication date: May 3, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Zenya Kawaguchi, Motoko Hara
  • Patent number: 6189129
    Abstract: In a method of processing figure arrays in a figure processing apparatus, first and second figure arrays are sequentially inputted. A fractionalizing process is selectively performed to divide each of figure elements of the second figure array into a plurality of types of fractions based on presence/non-presence of an overlapping portion between the first and second figure arrays and an array data of the second figure array. The array data indicates an array pitch in each of horizontal and vertical directions and a number of figures in the direction. A figure array of fractions is produced for each type and the produced figure arrays is registered in chain groups which includes a chain group of the first figure array, such that the registered figure arrays have the same array data. Then, a figure operating process is performed to the chain group.
    Type: Grant
    Filed: June 9, 1998
    Date of Patent: February 13, 2001
    Assignee: NEC Corporation
    Inventor: Takeshi Hamamoto
  • Patent number: 6166989
    Abstract: Data buses are arranged in a one-to-one correspondence to pads. These data buses are arranged in common to a plurality of memory arrays. A read data driver is rendered active selectively according to a word configuration to switch equivalently the connection between a memory array and a data bus.
    Type: Grant
    Filed: March 3, 1999
    Date of Patent: December 26, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Takuya Ariki, Mikio Asakura, Takayuki Nishiyama
  • Patent number: 6157588
    Abstract: First and second global input/output lines are twisted between first and second main blocks. First and second SD signal lines in the first main block are respectively arranged adjacent to first and second global input/output lines. First and second SD signal lines in the second main block are respectively arranged adjacent to the second and first global input/output lines. An SD signal supplied for the first or second SD signal line makes noises applied to the first and second global input/output lines identical, so that an influence by the noises is substantially eliminated between the first and second global input/output lines. As a result, the global input/output line is provided with higher resistance to noise without any increase in a layout area.
    Type: Grant
    Filed: January 13, 1999
    Date of Patent: December 5, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiro Matsumoto, Mikio Asakura, Takeshi Hamamoto, Kei Hamade
  • Patent number: 6091651
    Abstract: I/O lines in an I/O gate-sense amplifier portion are arranged in the order of IOA, /IOB, IOB, and /IOA. As a result, the potentials of adjacent I/O lines are necessarily different at the time of writing/reading the same data to/from a plurality of memory cells during a multi-bit test. Therefore, a short-circuit fault caused between adjacent I/O lines can be detected at the same time.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: July 18, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kiyohiro Furutani, Takeshi Hamamoto, Shigeru Kikuda
  • Patent number: 6087691
    Abstract: On a p.sup.++ substrate (1) provided is a p.sup.- epitaxial layer (2) having an impurity concentration lower than that of the p.sup.++ substrate (1). A p well (3) is formed in a portion of the p.sup.- epitaxial layer 2 and further n.sup.+ diffusion layers (4a and 4b) are selectively formed in the p well (3). A memory cell capacitor (5) is connected onto the n.sup.+ diffusion layer 4b. On the other hand, an no diffusion layer (6) is selectively formed in the p.sup.- epitaxial layer (2) separately from the p well (3), to which an external signal input circuit (7) is connected. Further, a p.sup.++ diffusion layer 9a is provided between the external signal input circuit (7) serving as a source for injection of the minority carriers, i.e., electrons and the n.sup.+ diffusion layer (4b) connected to the memory cell capacitor (5), for blocking the entry of the minority carries. The p.sup.++ diffusion layer (9a) extends up to such a depth as to reach the p.sup.++ substrate (1) from a surface of the p.sup.
    Type: Grant
    Filed: May 7, 1997
    Date of Patent: July 11, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Takeshi Hamamoto
  • Patent number: 6043528
    Abstract: A semiconductor memory device comprises a MOS-type transistor formed on a semiconductor substrate, a capacitor formed in the interior of an opening portion formed in the semiconductor substrate to be adjacent to the MOS-type transistor, the capacitor having a capacitor insulating film formed of a high dielectric film, and a line layer for connecting respective gate electrodes of the MOS-type transistor separated to be island-shaped to prevent from being presented on a region where the opening portion is formed, the line layer formed of a conductive layer different from the gate electrodes in its level.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: March 28, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masami Aoki, Takeshi Hamamoto
  • Patent number: 5995435
    Abstract: When an external RAS and external CAS are input to a RAS buffer and a CAS buffer, an internal RAS and an internal CAS are generated. The internal RAS is input to a clock generating circuit and a CBR mode determination circuit and the internal CAS is input to the CBR mode determination circuit. The clock generating circuit outputs a pump clock to first and second WL pumps upon input of internal RAS, and the first WL pump supplies charge to a Vpp power supply. If CAS is input prior to RAS during refresh operation, CBR mode determination circuit inputs a CBR mode signal to the second WL pump which supplies charge to Vpp power supply together with the first WL pump when the pump clock and the CBR mode signal is input thereto.
    Type: Grant
    Filed: August 21, 1998
    Date of Patent: November 30, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Kiyohiro Furutani, Yoshikazu Morooka
  • Patent number: 5986964
    Abstract: A semiconductor memory device of the present invention is provided with a plurality of memory cell arrays distributed and thus arranged and having the same function, and a main control circuit and local control circuits that are structured hierarchically. Each memory cell array has its operation controlled directly by any of the local control circuits, wherein the main control circuit including a command producing circuit which responds to an externally applied signal to produce a control signal corresponding to a predetermined mode of operation, and a global control circuit which responds to a control command to generate a control signal for operating the entire semiconductor memory device consistently. The local control circuits receive the control signal from the global control circuit to cause memory cell arrays to perform a predetermined operation.
    Type: Grant
    Filed: November 2, 1998
    Date of Patent: November 16, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takuya Ariki, Takeshi Hamamoto, Kiyohiro Furutani
  • Patent number: 5987619
    Abstract: An input signal phase compensation circuit having a monitor mode and a normal operation mode includes a mode switching circuit, a logic gate receiving an internal data signal, a delay circuit connected to the logic gate, and a phase comparator comparing, in the monitor mode, phases of a signal output from the delay circuit and a clock signal, and determining time for delaying an internal clock signal in a variable delay circuit so as to match phases of the both signals. In the normal operation mode, the time is fixed, and data is obtained at phase compensated timing.
    Type: Grant
    Filed: October 8, 1997
    Date of Patent: November 16, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Hamamoto, Masaki Tsukude
  • Patent number: 5936459
    Abstract: A first charge pumping circuit including a first capacitor and first and second switches, and a second charge pumping circuit including a second capacitor and third and fourth switches, are operated complementarily. The first capacitor is provided between first and second nodes, and the second capacitor is provided between third and fourth nodes. An NMOS transistor as equalizing means is provided between the first and third nodes. Before the start of supply of charges by the second switch to the second node and injection of charges by the third switch to an output node, the NMOS transistor is turned on, whereby potentials at the first and third nodes are equalized. Accordingly, the charges consumed by the first charge pumping circuit can be recycled by the second charge pumping circuit. Thus, lower power consumption is realized.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: August 10, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Takeshi Hamamoto