Patents by Inventor Yasuaki Hamada

Yasuaki Hamada 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: 7368774
    Abstract: A capacitor includes a lower electrode, a first dielectric film composed of lead zirconate titanate niobate formed above the lower electrode, a second dielectric film composed of lead zirconate titanate or lead zirconate titanate niobate with a Nb composition smaller than a Nb composition of the lead zirconate titanate niobate composing the first dielectric film, and an upper electrode formed above the second dielectric film.
    Type: Grant
    Filed: September 13, 2006
    Date of Patent: May 6, 2008
    Assignee: Seiko Epson Corporation
    Inventors: Yasuaki Hamada, Takeshi Kijima
  • Publication number: 20080060381
    Abstract: A ferroelectric film wherein 5 to 40 mol % in total of at least one of Nb, V, and W is included in the B site of a Pb(Zr,Ti)O3 ferroelectric which includes at least four-fold coordinated Si4+ or Ge4+ in the A site ion of a ferroelectric perovskite material in an amount of 1% or more. This enables to significantly improve reliability of the ferroelectric film.
    Type: Application
    Filed: October 23, 2007
    Publication date: March 13, 2008
    Applicant: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Hiromu Miyazawa, Yasuaki Hamada, Eiji Natori
  • Publication number: 20080037312
    Abstract: A ferroelectric memory includes: a memory cell having a ferroelectric capacitor, wherein, in a read-out operation, a first signal Q1 is given when a first voltage is applied to the ferroelectric capacitor, and a second signal Q2 is given when a second voltage having an identical magnitude as a magnitude of the first voltage in a different polarity is applied to the ferroelectric capacitor, and a judgment is made that the memory cell stores first data when Q1/Q2 is greater than 1/2, and second data when Q1/Q2 is smaller than 1/2.
    Type: Application
    Filed: April 11, 2007
    Publication date: February 14, 2008
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Yasuaki HAMADA
  • Patent number: 7303828
    Abstract: A ferroelectric film wherein 5 to 40 mol % in total of at least one of Nb, V, and W is included in the B site of a Pb(Zr,Ti)O3 ferroelectric which includes at least four-fold coordinated Si4+ or Ge4+ in the A site ion of a ferroelectric perovskite material in an amount of 1% or more. This enables to significantly improve reliability of the ferroelectric film.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: December 4, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Hiromu Miyazawa, Yasuaki Hamada, Eiji Natori
  • Publication number: 20070210361
    Abstract: A ferroelectric capacitor includes: a base substrate; a buffer layer formed above the base substrate; a lower electrode formed above the buffer layer; a ferroelectric layer formed above the lower electrode; and an upper electrode formed above the ferroelectric layer, wherein the buffer layer includes titanium (Ti) and cobalt (Co) as metal elements, and a metal element ratio x is 0.05?x<1, when Ti:Co=1?x:x.
    Type: Application
    Filed: February 28, 2007
    Publication date: September 13, 2007
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Yasuaki Hamada
  • Patent number: 7266007
    Abstract: A method for reading a nondestructive readout type ferroelectric memory device including a process in which 1-bit data is written in a pair of a cell for storage and a cell for reference disposed in series in the ferroelectric memory device, and a process in which a response obtained when a pulse is impressed to the 1-bit data written in the pair of a cell for storage and a cell for reference is resonated by a resonant circuit with a specified resonance frequency provided at a readout side to thereby output an output signal to be nondestructively readout.
    Type: Grant
    Filed: March 24, 2005
    Date of Patent: September 4, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Yasuaki Hamada
  • Patent number: 7262450
    Abstract: A MFS type field effect transistor includes a semiconductor layer, a PZT system ferroelectric layer formed on the semiconductor layer, a gate electrode formed on the PZT system ferroelectric layer, and an impurity layer composing a source or a drain, formed in the semiconductor layer. The PZT system ferroelectric layer includes Nb that replaces a Ti composition by 2.5 mol % or more but 40 mol % or less.
    Type: Grant
    Filed: April 19, 2005
    Date of Patent: August 28, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Yasuaki Hamada
  • Patent number: 7255941
    Abstract: A ferroelectric film is formed by an oxide that is described by a general formula AB1?xNbxO3. An A element includes at least Pb, and a B element includes at least one of Zr, Ti, V, W, Hf and Ta. The ferroelectric film includes Nb within the range of: 0.05?x<1. The ferroelectric film can be used for any of ferroelectric memories of 1T1C, 2T2C and simple matrix types.
    Type: Grant
    Filed: October 22, 2003
    Date of Patent: August 14, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Yasuaki Hamada, Eiji Natori, Koji Ohashi
  • Publication number: 20070170479
    Abstract: A polarization transfer device includes a ferroelectric thin film formed continuously as one piece; a plurality of polarization switches formed by placing the ferroelectric thin film between a first gate electrode and a second gate electrode; and a plurality of polarization accumulators formed by placing the ferroelectric thin film between a first electrode plate and a second electrode plate, wherein the plurality of polarization switches and the plurality of polarization accumulators are arranged alternately.
    Type: Application
    Filed: January 16, 2007
    Publication date: July 26, 2007
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Masami Hashimoto, Takeshi Kijima, Yasuaki Hamada, Akio Konishi, Tatsuya Shimoda
  • Publication number: 20070163879
    Abstract: A method of manufacturing an insulating target material for obtaining an insulating complex oxide film of a general formula AB1-xCxO3, the method including: mixing an oxide of an element A, an oxide of an element B, and an oxide of an element C, subjecting the mixed powder to heat treatment, and pulverizing the resulting product to obtain a first powder; mixing the first powder and a solution including at least one of an Si raw material and a Ge raw material and obtaining a second powder from the mixture of the first powder and the solution; subjecting the second powder to heat treatment and pulverizing the resulting product to obtain a third powder; and subjecting the third powder to heat treatment.
    Type: Application
    Filed: January 18, 2007
    Publication date: July 19, 2007
    Inventors: Koji Ohashi, Takeshi Kijima, Setsuya Iwashita, Yasuaki Hamada
  • Publication number: 20070138522
    Abstract: A memory device including: a lower electrode; a ferroelectric layer formed above the lower electrode; a charge compensation layer formed above the ferroelectric layer and including an oxide having a composition differing from a composition of the ferroelectric layer; and upper electrodes formed above the charge compensation layer. The upper electrodes includes: a saturated polarization forming electrode used for forming a domain polarized to saturation in a predetermined direction in a predetermined region of the ferroelectric layer; a writing electrode disposed apart from the saturated polarization forming electrode; and a reading electrode disposed apart from the writing electrode.
    Type: Application
    Filed: December 14, 2006
    Publication date: June 21, 2007
    Inventors: Takeshi Kijima, Yasuaki Hamada, Tatsuya Shimoda
  • Publication number: 20070119343
    Abstract: A complex metal oxide raw material composition used for forming a complex metal oxide, the complex metal oxide being shown by a general formula AB1-xCxO3, wherein an element A includes at least Pb, an element B includes at least one of Zr, Ti, V, W, and Hf, and an element C includes at least one of Nb and Ta, and the raw material composition including: at least one of a thermally-decomposable organometallic compound including the element A, the element B, or the element C, a hydrolyzable organometallic compound including the element A, the element B, or the element C, and a partial hydrolyzate and/or a polycondensate of the hydrolyzable organometallic compound; at least one of a polycarboxylic acid and a polycarboxylic acid ester; and an organic solvent.
    Type: Application
    Filed: November 28, 2006
    Publication date: May 31, 2007
    Applicant: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Yasuaki Hamada, Mayumi Ueno
  • Patent number: 7214977
    Abstract: A ferroelectric thin film formed of a highly oriented polycrystal in which 180° domains and 90° domains arrange at a constant angle to an applied electric field direction in a thin film plane and reversely rotate in a predetermined electric field.
    Type: Grant
    Filed: October 4, 2005
    Date of Patent: May 8, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Takeshi Kijima, Yasuaki Hamada, Eiji Natori
  • Publication number: 20070075355
    Abstract: A capacitor includes a lower electrode, a first dielectric film composed of lead zirconate titanate niobate formed above the lower electrode, a second dielectric film composed of lead zirconate titanate or lead zirconate titanate niobate with a Nb composition smaller than a Nb composition of the lead zirconate titanate niobate composing the first dielectric film, and an upper electrode formed above the second dielectric film.
    Type: Application
    Filed: September 13, 2006
    Publication date: April 5, 2007
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Yasuaki Hamada, Takeshi Kijima
  • Publication number: 20070054038
    Abstract: A complex oxide laminate including: a substrate; a first complex oxide layer represented by a general formula ABO3 formed above the substrate; and a second complex oxide layer represented by a general formula AB1?xCxO3 formed above the first complex oxide layer, an element A including at least Pb, an element B including at least one of Zr, Ti, V, W, and Hf, and an element C including at least one of Nb and Ta.
    Type: Application
    Filed: August 31, 2006
    Publication date: March 8, 2007
    Inventors: Takeshi Kijima, Koji Ohashi, Yasuaki Hamada
  • Patent number: 7187025
    Abstract: A ferroelectric material for forming a ferroelectric that is described by a general formula ABO3, includes an A-site compensation component which compensates for a vacancy of an A site, and a B-site compensation component which compensates for a vacancy of a B site.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: March 6, 2007
    Assignee: Seiko Epson Corporation
    Inventors: Yasuaki Hamada, Takeshi Kijima, Junichi Karasawa, Koji Ohashi, Eiji Natori
  • Publication number: 20070040243
    Abstract: An insulating target material for obtaining a conductive complex oxide film represented by a general formula ABO3, the insulating target material including an oxide of an element A, an oxide of an element B, and at least one of an Si compound and a Ge compound.
    Type: Application
    Filed: August 15, 2006
    Publication date: February 22, 2007
    Inventors: Koji Ohashi, Setsuya Iwashita, Takeshi Kijima, Yasuaki Hamada
  • Patent number: 7142445
    Abstract: A ferroelectric memory device preventing an imprint and including a plurality of wordlines, a plurality of bitlines, a plurality of ferroelectric memory cells, a wordline driver which drives the wordlines, and a bitline driver which drives the bitlines. The wordline driver and the bitline driver switch an operation mode of the ferroelectric memory device to a first mode which is one of a data reading mode, a data rewriting mode and a data writing mode, by applying a voltage Vs having a first polarity to at least one ferroelectric memory cell selected from the ferroelectric memory cells.
    Type: Grant
    Filed: September 2, 2004
    Date of Patent: November 28, 2006
    Assignee: Seiko Epson Corporation
    Inventors: Yasuaki Hamada, Takeshi Kijima, Eiji Natori
  • Patent number: 7074624
    Abstract: A method of manufacturing a ferroelectric film includes crystallizing a raw material having a complex oxide, the method including: performing a heat treatment in a first condition in which a predetermined pressure and a predetermined temperature are applied; and maintaining a second condition, in which a pressure and a temperature lower than the pressure and the temperature in the first condition are applied, after the heat treatment in the first condition, and the raw material is crystallized by repeating the heat treatment in the first condition and the maintaining the second condition.
    Type: Grant
    Filed: March 25, 2004
    Date of Patent: July 11, 2006
    Assignee: Seiko Epson Corporation
    Inventors: Koji Ohashi, Takeshi Kijima, Junichi Karasawa, Yasuaki Hamada, Eiji Natori
  • Publication number: 20060140031
    Abstract: A method of manufacturing a ferroelectric film including: (a) mixing a polycarboxylate containing niobium, a polycarboxylate containing bismuth, a polycarboxylic acid or a polycarboxylic acid ester, and an organic solvent; and (b) applying the resulting mixed solution to a substrate and heat-treating the applied mixed solution to form a ferroelectric film including BiNbO4.
    Type: Application
    Filed: December 22, 2005
    Publication date: June 29, 2006
    Inventors: Takeshi Kijima, Yasuaki Hamada, Tomokazu Kobayashi