Patents by Inventor Zhiqiang Wei

Zhiqiang Wei 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: 20100046270
    Abstract: A resistance variable memory apparatus (100) of the present invention is a resistance variable memory apparatus (100) using a resistance variable element (22) transitioning between plural resistance states in response to electric pulses of the same polarity, in which a series resistance setting unit (10) is configured to set a resistance value of the series current path and a parallel resistance setting unit (30) is configured to set a resistance value of a parallel current path such that the resistance values become resistance values at which a node potential is not larger than a second voltage level in a state where an electric pulse application device (50) is outputting a first electric pulse after the resistance variable element (22) has switched to the high-resistance state, and the node potential is not larger than a first voltage level in the state where the electric pulse application device (50) is outputting a second electric pulse after the resistance variable element (22) has switched to the low-re
    Type: Application
    Filed: November 16, 2007
    Publication date: February 25, 2010
    Inventors: Yoshikazu Katoh, Kazuhiko Shimakawa, Zhiqiang Wei
  • Publication number: 20100014343
    Abstract: [Objective] A nonvolatile memory apparatus and a nonvolatile data storage medium of the present invention, including nonvolatile memory elements each of which changes its resistance in response to electric pulses applied, comprises a first write circuit (106) for performing first write in which a first electric pulse is applied to the nonvolatile memory element to switch a resistance value of the nonvolatile memory element from a first resistance value to a second resistance value and a second electric pulse which is opposite in polarity to the first electric pulse is applied to the nonvolatile memory element to switch the resistance value of the nonvolatile memory element from the second resistance value to the first resistance value; and a second write circuit (108) for performing second write in which a third electric pulse is applied to the nonvolatile memory element to switch the resistance value of the nonvolatile memory element from a third resistance value to a fourth resistance value and a fourth ele
    Type: Application
    Filed: October 28, 2008
    Publication date: January 21, 2010
    Inventors: Zhiqiang Wei, Takeshi Takagi, Ken Kawai, Kazuhiko Shimakawa
  • Publication number: 20090014710
    Abstract: A lower electrode layer 2, an upper electrode layer 4 formed above the lower electrode layer 2, and a metal oxide thin film layer 3 formed between the lower electrode layer 2 and the upper electrode layer 4 are provided. The metal oxide thin film layer 3 includes a first region 3a whose value of resistance increases or decreases by an electric pulse that is applied between the lower electrode layer 2 and the upper electrode layer 4 and a second region 3b arranged around the first region 3a and having a larger content of oxygen than the first region 3a, wherein the lower and upper electrode layers 2 and 4 and at least a part of the first region 3a are arranged so as to overlap as viewed from the direction of the thickness of the first region 3a.
    Type: Application
    Filed: March 6, 2007
    Publication date: January 15, 2009
    Inventors: Yoshio Kawashima, Takeshi Takagi, Takumi Mikawa, Zhiqiang Wei
  • Publication number: 20060081961
    Abstract: The present invention offers a variable resistance device and a semiconductor apparatus that have component parts less subject to damage and thereby ensure stable quality at a high yield, even if the manufacturing processes include operations in a deoxidizing atmosphere or an oxidizing atmosphere. The variable resistance device of the present invention comprises: a variable resistance layer made of a metal oxide and causing changes in electric resistance thereof in accordance with control conditions; and a hydrogen-diffusion preventing layer which surrounds at least part of the variable resistance layer and prevents hydrogen from diffusing into the variable resistance layer.
    Type: Application
    Filed: September 22, 2005
    Publication date: April 20, 2006
    Inventors: Keisuke Tanaka, Yoshihisa Kato, Zhiqiang Wei
  • Publication number: 20060081962
    Abstract: The variable resistance device of the present invention comprises a variable resistance layer. The variable resistance layer is made of a material which has an electric resistance changing in accordance with an applied electric field and maintains the electric resistance after being changed in a nonvolatile manner. Provided for the variable resistance layer are four electrodes independent of each other. Of them, two electrodes constitute a control electrode pair, while the remaining two electrodes constituting a read electrode pair. The controle electrode pair is formed for applying an electric field to the variable resistance layer. On the other hand, the read electrode pair is formed as a data path making use of changes in the electric resistance.
    Type: Application
    Filed: September 22, 2005
    Publication date: April 20, 2006
    Inventors: Zhiqiang Wei, Yoshihisa Kato
  • Patent number: 6803702
    Abstract: When a piezoelectric material is manufactured by hydrothermal method, the proper amount of lead contained in the piezoelectric film can be ensured and decreases in piezoelectric characteristics can be prevented. A method for manufacturing a piezoelectric material expressed by the formula ABO3, containing an element “a” as the element expressed by A above, and having a perovskite crystal structure, comprises a first step of producing an oxide containing an element “a′”, and a second step of producing a piezoelectric material by subjecting the oxide produced in the first step to a hydrothermal processing using an aqueous solution containing the element “a”, wherein the amount of the element “a”, contained in the piezoelectric material produced in the second step is increased over the amount of the element “a” contained in the oxide produced in the first step.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: October 12, 2004
    Assignee: Seiko Epson Corporation
    Inventors: Hong Qiu, Koji Sumi, Tsutomu Nishiwaki, Masanori Okuyama, Zhiqiang Wei
  • Publication number: 20040058066
    Abstract: The present invention relates to a method for preparing a thin film of metal oxide containing one or more metal elements on a substrate. The method includes the steps of applying a sol-gel solution containing the one or more metal elements to a surface of the substrate, drying the sol-gel solution to prepare a dried gel film on the substrate, soaking the dried gel film on the substrate in an alkaline aqueous solution containing at least one kind of metal element among the one or more metal elements in a container, sealing the container, and performing hydrothermal treatment for the dried gel film on the substrate in the sealed container to prepare a thin film of metal oxide on the substrate.
    Type: Application
    Filed: September 22, 2003
    Publication date: March 25, 2004
    Inventors: Zhiqiang Wei, Minoru Noda, Masanori Okuyama
  • Patent number: 6419849
    Abstract: When a piezoelectric material is manufactured by hydrothermal method, the proper amount of lead contained in the piezoelectric film can be ensured and decreases in piezoelectric characteristics can be prevented. A method for manufacturing a piezoelectric material expressed by the formula ABO3, containing an element “a” as the element expressed by A above, and having a perovskite crystal structure, comprises a first step of producing an oxide containing an element “a′”, and a second step of producing a piezoelectric material by subjecting the oxide produced in the first step to a hydrothermal processing using an aqueous solution containing the element “a”, wherein the amount of the element “a” contained in the piezoelectric material produced in the second step is increased over the amount of the element “a” contained in the oxide produced in the first step.
    Type: Grant
    Filed: March 27, 2000
    Date of Patent: July 16, 2002
    Assignee: Seiko Epson Corporation
    Inventors: Hong Qiu, Koji Sumi, Tsutomu Nishiwaki, Masanori Okuyama, Zhiqiang Wei
  • Publication number: 20020071969
    Abstract: When a piezoelectric material is manufactured by hydrothermal method, the proper amount of lead contained in the piezoelectric film can be ensured and decreases in piezoelectric characteristics can be prevented. A method for manufacturing a piezoelectric material expressed by the formula ABO3, containing an element “a” as the element expressed by A above, and having a perovskite crystal structure, comprises a first step of producing an oxide containing an element “a′”, and a second step of producing a piezoelectric material by subjecting the oxide produced in the first step to a hydrothermal processing using an aqueous solution containing the element “a”, wherein the amount of the element “a”, contained in the piezoelectric material produced in the second step is increased over the amount of the element “a” contained in the oxide produced in the first step.
    Type: Application
    Filed: January 18, 2002
    Publication date: June 13, 2002
    Inventors: Hong Qiu, Koji Sumi, Tsutomu Nishiwaki, Masanori Okuyama, Zhiqiang Wei