Patents by Inventor Akitoshi Nishimura

Akitoshi Nishimura 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: 6728128
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: April 27, 2004
    Assignee: Texas Instrument Incorporated
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Patent number: 6724646
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: April 20, 2004
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Patent number: 6721200
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: April 13, 2004
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Publication number: 20030202391
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Application
    Filed: March 26, 2003
    Publication date: October 30, 2003
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Publication number: 20030185072
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Application
    Filed: March 26, 2003
    Publication date: October 2, 2003
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Publication number: 20030179632
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in a ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Application
    Filed: March 26, 2003
    Publication date: September 25, 2003
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Patent number: 6587367
    Abstract: A ferroelectric memory structure is described for the 1T1C arrangement in ferroelectric capacitor cell array for FeRAM memory device applications. The device structure provides an accurate reference voltage and a simple sensing scheme for the sense amplifier used for reading the state of a target memory cell of the FeRAM array. A reference circuit generates a reference voltage which is a function of a charge shared between a plurality of FeRAM dummy cells. Each dummy cell of the plurality of FeRAM dummy cells is selectively coupleable to a plurality of bitlines. A shorting transistor in the reference circuit couples two bitlines or two bitline-bars neighboring the selected target memory cell. One dummy cell is coupled to a select one of the two shorted bitlines or bitline-bars, and another dummy cell is coupled to a another of the two shorted bitlines or bitline-bars, wherein at least one dummy cell is biased to a “0” state, and at least one other dummy cell is biased to a “1” state.
    Type: Grant
    Filed: March 19, 2002
    Date of Patent: July 1, 2003
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Yukio Fukuda, Katsuhiro Aoki
  • Patent number: 6534808
    Abstract: A photocell for detecting light includes at least two tiers or structures, one disposed over the other, each tier having a metal-insulator-semiconductor (M-I-S) or a semiconductor-insulator-metal (S-I-M) structure. Each M-I-S structure includes a semiconductor diffusion layer capable of developing a depletion region, a thin insulator layer disposed on the diffusion layer, and a contact layer disposed on the thin insulator layer. Each S-I-M structure includes a contact layer, a thin insulator layer disposed on the contact layer, and a semiconductor diffusion layer disposed on the thin insulator layer, the semiconductor layer capable of developing a depletion region. When light is incident on each depletion region, a current indicative of the light detected in each depletion region flows through the respective contact layer. Also provided is a semiconductor-insulator-metal (S-I-M) structure that detects light. Two- and three-tiered photocells made of M-I-S and/or S-I-M structures are also provided.
    Type: Grant
    Filed: January 11, 2001
    Date of Patent: March 18, 2003
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Ichiro Fujii
  • Publication number: 20020125514
    Abstract: A photocell for detecting light includes at least two tiers or structures, one disposed over the other, each tier having a metal-insulator-semiconductor (M-I-S) or a semiconductor-insulator-metal (S-I-M) structure. Each M-I-S structure includes a semiconductor diffusion layer capable of developing a depletion region, a thin insulator layer disposed on the diffusion layer, and a contact layer disposed on the thin insulator layer. Each S-I-M structure includes a contact layer, a thin insulator layer disposed on the contact layer, and a semiconductor diffusion layer disposed on the thin insulator layer, the semiconductor layer capable of developing a depletion region. When light is incident on each depletion region, a current indicative of the light detected in each depletion region flows through the respective contact layer. Also provided is a semiconductor-insulator-metal (S-I-M) structure that detects light. Two- and three-tiered photocells made of M-I-S and/or S-I-M structures are also provided.
    Type: Application
    Filed: January 11, 2001
    Publication date: September 12, 2002
    Inventors: Akitoshi Nishimura, Ichiro Fujii
  • Patent number: 6373127
    Abstract: A semiconductor device is disclosed. The device includes an integrated circuit chip having integral de-coupling capacitors on the chip backside. The de-coupling capacitors includes a metal layer in intimate contact with the semiconductor substrate of the integrated circuit, a dielectric layer and a second metal layer. The second metal layer is segmented to form multiple capacitors, and each capacitor is interconnected to power supplies of the chip. Interconnection to different integrated circuit packages is provided. A method of making the semiconductor device is also disclosed.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: April 16, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Daniel Baudouin, Adin Hyslop, Akitoshi Nishimura, Jeffrey Janzen, Mark Kressley
  • Patent number: 6363002
    Abstract: An FeRAM in which sensing occurs without a dummy cell, using an unselected bitline as a reference. The read cycle includes two opposed pulses on the drive line: the first pulse provides a data-dependent signal out of the selected cell, and the second pulse restores the bit line to a level such that the DC bias voltage on an unselected bitline provides an optimal reference.
    Type: Grant
    Filed: December 31, 1998
    Date of Patent: March 26, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Katsuhiro Aoki
  • Patent number: 6342420
    Abstract: An apparatus and method for fabrication a hexagonally symmetric cell, (e.g., a dynamic random access memory cell (100)). The cell can comprise a bitline contact (38), storage node contacts (32) hexagonally surrounding the bitline contact (38), storage nodes (36) also surrounding the bitline contact (38), a wordline (30) portions of which form field effect transistor gates. Large distances between bitline contacts (38) and storage node contact (32) cause large problems during photolithography because dark areas are difficult to achieve when using Levenson Phaseshift. Because Levenson Phaseshift depends on wave cancellations between nearby features, commonly known as destructive interferences, the resultant printability of the pattern is largely a function of the symmetry and separation distances. When non-symmetries in the pattern occur, the result is weaker cancellations of fields (i.e. between features) and a large loss of image contrast and depth of focus during the printing step.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: January 29, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Yasutoshi Okuno, Rajesh Khamankar, Shane R. Palmer
  • Patent number: 6297085
    Abstract: To provide a method that can be used to form a high-qualility ferroelectric film by forming good nuclei when using the sputtering method to manufacture a PZT capacitor or other forroelectric capacitors using Ir or other electrode substances in addition to Pt for the electrode. In the method for manufacturing a PZT ferroelectric capacitor CAP, after titanium film 31 is deposited on Ir electrode 6, lead oxide 32 is deposited at a substrate temperature higher than the crystallization temperature of lead titanate using the sputtering method. Lead zirconate titanate 34 is then deposited at a substrate temperature higher than the aforementioned substrate temperature using the sputtering temperature. Afterwards, a heat treatment of the deposited film is performed to produce PZT film 17.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: October 2, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Katsuhiro Aoki, Yukio Fukuda, Ikuko Murayama, Ken Numata, Akitoshi Nishimura
  • Patent number: 6166408
    Abstract: An apparatus and method for fabrication a hexagonally symmetric cell, (e.g., a dynamic random access memory cell (100)). The cell can comprise a bitline contact (38), storage node contacts (32) hexagonally surrounding the bitline contact (38), storage nodes (36) also surrounding the bitline contact (38), a wordline (30) portions of which form field effect transistor gates. Large distances between bitline contacts (38) and storage node contacts (32) cause large problems during photolithography because dark areas are difficult to achieve when using Levenson Phaseshift. Because Levenson Phaseshift depends on wave cancellations between nearby features, commonly known as destructive interferences, the resultant printability of the pattern is largely a function of the symmetry and separation distances. When non-symmetries in the pattern occur, the result is weaker cancellations of fields (i.e. between features) and a large loss of image contrast and depth of focus during the printing step.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: December 26, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Akitoshi Nishimura, Yasutoshi Okuno, Rajesh Khamankar, Shane R. Palmer
  • Patent number: 6150183
    Abstract: A metal oxide capacitor is manufactured by sequentially laminating a metal oxide film and a secon electrode on a first electrode. The metal oxide film is formed and then heat-treated in an atmosphere with an oxygen pressure higher than 1 atm.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: November 21, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Yukio Fukuda, Katsuhiro Aoki, Akitoshi Nishimura, Ken Numata
  • Patent number: 6033953
    Abstract: A dielectric capacitor is provided which has a reduced leakage current. The surface of a first electrode (38) of the capacitor is electropolished and a dielectric film (40) and a second electrode (37) are successively laminated on it. The convex parts pointed end (38a) existing on the surface of the first electrode is very finely polished uniformly by dissolving according to electropolishing, a spherical curved surface in which the radius of curvature has been enlarged is formed, and the surface of the first electrode is flattened. Therefore, concentration of electrolysis can be prevented during the operation at the interface of the first electrode and the dielectric film, and the leakage current can be reduced considerably.
    Type: Grant
    Filed: December 16, 1997
    Date of Patent: March 7, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Katsuhiro Aoki, Yukio Fukuda, Ken Numata, Yasutoshi Okuno, Akitoshi Nishimura
  • Patent number: 5840615
    Abstract: A method for forming a ferroelectric material film, more particularly a lead zirconate titanate (PZT) film by the sol-gel method wherein a lowered oxidative sintering temperature may be adopted in preparing the ferroelectric material film with a perovskite crystalline structure, thereby reducing the risk of oxidation of metal electrodes and other circuits when the ferroelectric material film is employed as a dielectric in semiconductor devices, such as in a capacitor, for example. The method contemplates the preparation of a raw material solution containing an organometallic compound of a metallic element forming the ferroelectric material film, alkanolamine and/or stabilizer comprising a .beta.-diketone, with the concentration of the stabilizer being sufficient to provide a mole ratio to the total metal atoms of (stabilizer/total metal atoms)>3.
    Type: Grant
    Filed: March 3, 1997
    Date of Patent: November 24, 1998
    Assignee: Texas Instruments Incorporated
    Inventors: Katsuhiro Aoki, Yukio Fukuda, Akitoshi Nishimura, Tomomi Nagao, Shinichi Hachiya
  • Patent number: 5793600
    Abstract: A capacitor and electrode structure comprising a PZT ferroelectric layer 17 with a primary component (Pb) and secondary component (Ti), a lower electrode layer 16 formed on the underside of the ferroelectric layer and made up of a special element (Pt) and Ti, and compounds thereof, and a diffusion barrier layer 18 which is formed on the underside of the lower electrode layer and which functions as a diffusion barrier with respect to Pb. The capacitor and the electrode structure, which may be a component of a semiconductor memory device, suppress fluctuations in the composition of the ferroelectric layer in PZT, etc., so as to maintain the intended performance of the PZT ferroelectric layer, thereby simplifying and stabilizing film fabrication, and preventing the degradation of electrical characteristics and adverse effects on lower layers.
    Type: Grant
    Filed: October 20, 1995
    Date of Patent: August 11, 1998
    Assignee: Texas Instruments Incorporated
    Inventors: Yukio Fukuda, Katsuhiro Aoki, Akitoshi Nishimura, Ken Numata
  • Patent number: 5776788
    Abstract: A method for forming a PZT strong dielectric film by the sol-gel technique, in which the thickness of the film is substantially no greater than 1000 .ANG.. In another aspect, the drying temperature of the raw material sol-gel solution for forming the PZT dielectric film is maintained within the range of 130.degree.-200.degree. C., and is particularly set lower than the boiling point of the stabilizer contained in the sol-gel raw material and higher than the boiling point of the solvent contained in the sol-gel raw material. As a result of performing the oxidative sintering treatment at a temperature at which perovskite crystals form, it becomes possible to readily form thin films exhibiting a (100) crystal orientation in particular. Additionally, completely crack-free thick films can be formed.
    Type: Grant
    Filed: February 15, 1996
    Date of Patent: July 7, 1998
    Assignee: Texas Instruments Incorporated
    Inventors: Katsuhiro Aoki, Yukio Fukuda, Akitoshi Nishimura
  • Patent number: 5654567
    Abstract: A capacitor, electrode, or wiring structure having an alpha ray emitting source (in particular, a Pt electrode), and an alpha ray shielding layer 18, having at least one type selected from the group of simple metals of nickel, cobalt, copper, and tungsten, their compounds or alloys made of at least two types of these simple metals, and compounds and alloys made of these simple metals and silicon is provided. It is possible to shield off the alpha ray effectively, to suppress generation of soft errors, to enable the use of Pt and other new materials in making the electrodes and wiring, and to reduce the cost of the mold resin.
    Type: Grant
    Filed: October 1, 1996
    Date of Patent: August 5, 1997
    Assignee: Texas Instruments Incorporated
    Inventors: Ken Numata, Katsuhiro Aoki, Yukio Fukuda, Akitoshi Nishimura