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).

  • Patent number: 8710484
    Abstract: A manufacturing method for manufacturing, with a simple process, a non-volatile memory apparatus having a stable memory performance includes: (a) forming a stacking-structure body above a substrate by alternately stacking conductive layers comprising a transition metal and interlayer insulating films comprising an insulating material; (b) forming a contact hole penetrating through the stacking-structure body to expose part of each of the conductive layers; (c) forming variable resistance layers by oxidizing the part of each of the conductive layers, the part being exposed in the contact hole, and each of the variable resistance layers having a resistance value that reversibly changes according to an application of an electric signal; and (d) forming a pillar electrode in the contact hole by embedding a conductive material in the contact hole, the pillar electrode being connected to each of the variable resistance layers.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: April 29, 2014
    Assignee: Panasonic Corporation
    Inventors: Zhiqiang Wei, Takeshi Takagi, Mitsuteru Iijima
  • Publication number: 20140061579
    Abstract: A variable resistance nonvolatile memory element includes a first electrode, a second electrode, and a variable resistance layer including: a first oxide layer including a metal oxide having non-stoichiometric composition and including p-type carriers; a second oxide layer located between and in contact with the first oxide layer and a second electrode and including a metal oxide having non-stoichiometric composition and including n-type carriers; an oxygen reservoir region located in the first oxide layer, having no contact with the first electrode, and having an oxygen content atomic percentage higher than that of the first oxide layer; and a local region located in the second oxide layer, having contact with the oxygen reservoir region, and having an oxygen content atomic percentage lower than that of the second oxide layer.
    Type: Application
    Filed: October 22, 2012
    Publication date: March 6, 2014
    Applicant: PANASONIC CORPORATION
    Inventors: Zhiqiang Wei, Takeshi Takagi, Koji Katayama
  • Publication number: 20140063909
    Abstract: In a nonvolatile memory element, when a voltage value of an electric pulse has a relationship of V2>V1>0 V>V3>V4 and a resistance value of a variable resistance layer has a relationship of R3>R2>R4>R1, the resistance value of the variable resistance layer becomes: R2, when the electric pulse having a voltage value of V2 or greater is applied between electrodes; R4, when the electric pulse having a voltage value of V4 or smaller is applied between the electrodes; R3, when the resistance value of the variable resistance layer is R2 and the electric pulse having a voltage value of V3 is applied between the electrodes; and R1, when the resistance value of the variable resistance layer is R4 and the electric pulse having a voltage value of V1 is applied between the electrodes.
    Type: Application
    Filed: October 15, 2012
    Publication date: March 6, 2014
    Applicant: PANASONIC CORPORATION
    Inventors: Shunsaku Muraoka, Zhiqiang Wei, Takeshi Takagi
  • Publication number: 20140056056
    Abstract: A method for reading data from a nonvolatile memory element including a first electrode, a second electrode, and a variable resistance layer which includes a local region having a higher degree of oxygen deficiency than a surrounding region, the method including: applying a third voltage pulse between the first electrode and the second electrode, the third voltage pulse having a voltage with an absolute value smaller than absolute values of voltages of the first voltage pulse and the second voltage pulse; and reading the resistance state of the variable resistance layer by applying a fourth voltage pulse between the first electrode and the second electrode after the applying of a third voltage pulse, the fourth voltage pulse having a voltage with an absolute value smaller than the absolute values of the voltages of the first voltage pulse and the second voltage pulse.
    Type: Application
    Filed: February 15, 2013
    Publication date: February 27, 2014
    Applicant: Panasonic Corporation
    Inventors: Takeshi Takagi, Zhiqiang Wei, Takeki Ninomiya
  • Publication number: 20140050013
    Abstract: A nonvolatile memory element includes: a first electrode; a second electrode; and a variable resistance layer comprising a metal oxide positioned between the first electrode and the second electrode. The variable resistance layer includes: a first oxide layer having a resistivity ?x, on the first electrode; a second oxide layer having a resistivity ?y (?x<?y), on the first oxide layer; a third oxide layer having a resistivity ?z (?y<?z), on the second oxide layer; and a localized region that is positioned in the third oxide layer and the second oxide layer to be in contact with the second electrode and not to be in contact with the first oxide layer, and is, in resistivity, lower than the third oxide layer and different from the second oxide layer.
    Type: Application
    Filed: November 8, 2012
    Publication date: February 20, 2014
    Applicant: Panasonic Corporation
    Inventors: Zhiqiang Wei, Takeki Ninomiya, Takeshi Takagi
  • Publication number: 20130286714
    Abstract: Provided is a data write method for writing data to a nonvolatile memory element, the data write method including: a first application step of applying a first voltage pulse for changing a resistance state of the nonvolatile memory element from a first state to a second state; a second application step of applying a second voltage pulse which has a same polarity as the first voltage pulse and a voltage value of which has a smaller absolute value than the first voltage pulse; a determination step of determining whether the resistance state of the nonvolatile memory element is the second state; and a third application step of applying a third voltage pulse for changing the resistance state of the nonvolatile memory element from the first state to the second state when it is determined that the resistance state of the nonvolatile memory element is not the second state.
    Type: Application
    Filed: September 25, 2012
    Publication date: October 31, 2013
    Applicant: Panasonic Corporation
    Inventors: Takeshi Takagi, Zhiqiang Wei
  • Patent number: 8565005
    Abstract: A nonvolatile memory element includes: a first electrode layer; a second electrode layer; and a variable resistance layer which is placed between the electrode layers, and whose resistance state reversibly changes between a high resistance state and a low resistance state based on a polarity of a voltage applied between the electrode layers. The variable resistance layer is formed by stacking a first oxide layer including an oxide of a first transition metal and a second oxide layer including an oxide of a second transition metal which is different from the first transition metal. At least one of the following conditions is satisfied: (1) a dielectric constant of the second oxide layer is larger than a dielectric constant of the first oxide layer; and (2) a band gap of the second oxide layer is smaller than a band gap of the first oxide layer.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: October 22, 2013
    Assignee: Panasonic Corporation
    Inventors: Takeshi Takagi, Zhiqiang Wei, Takeki Ninomiya, Shunsaku Muraoka, Yoshihiko Kanzawa
  • Publication number: 20130250658
    Abstract: A nonvolatile memory device includes: a first electrode; a second electrode; and a variable resistance layer which includes: a first oxide layer including a first metal oxide; a second oxide layer located between and in contact with the first oxide layer and a second electrode including a second metal oxide and having a degree of oxygen deficiency lower than a degree of oxygen deficiency of the first oxide layer; and a local region located in the first oxide layer and the second oxide layer, having contact with the second electrode and no contact with the first electrode, and having a degree of oxygen deficiency higher than the degree of oxygen deficiency of the second oxide layer and different from the degree of oxygen deficiency of the first oxide layer.
    Type: Application
    Filed: October 3, 2012
    Publication date: September 26, 2013
    Applicant: Panasonic Corporation
    Inventors: Zhiqiang Wei, Takeshi Takagi, Satoru Mitani, Shunsaku Muraoka, Koji Katayama
  • Patent number: 8471235
    Abstract: A nonvolatile memory element includes a substrate; a lower electrode layer and a resistive layer sequentially formed on the substrate; a resistance variable layer formed on the resistive layer; a wire layer formed above the lower electrode layer; an interlayer insulating layer disposed between the substrate and the wire layer and covering at least the lower electrode layer and the resistive layer, the interlayer insulating layer being provided with a contact hole extending from the wire layer to the resistance variable layer; and an upper electrode layer formed inside the contact hole such that the upper electrode layer is connected to the resistance variable layer and to the wire layer; resistance values of the resistance variable layer changing reversibly in response to electric pulses applied between the lower electrode layer and the upper electrode layer.
    Type: Grant
    Filed: December 4, 2009
    Date of Patent: June 25, 2013
    Assignee: Panasonic Corporation
    Inventors: Yoshio Kawashima, Takumi Mikawa, Zhiqiang Wei, Atsushi Himeno
  • Patent number: 8445885
    Abstract: A nonvolatile memory element includes first and second electrodes, and a resistance variable layer disposed therebetween. At least one of the first and second electrodes includes a platinum-containing layer. The resistance variable layer includes a first oxygen-deficient transition metal oxide layer which is not physically in contact with the platinum-containing layer and a second oxygen-deficient transition metal oxide layer which is disposed between the first oxygen-deficient transition metal oxide layer and the platinum-containing layer and is physically in contact with the platinum-containing layer. When oxygen-deficient transition metal oxides included in the first and second oxygen-deficient transition metal oxide layers are expressed as MOx, and MOy, respectively, x<y is satisfied. The platinum-containing layer has a thickness which is not less than 1 nm and not more than 23 nm.
    Type: Grant
    Filed: December 1, 2009
    Date of Patent: May 21, 2013
    Assignee: Panasonic Corporation
    Inventors: Yoshihiko Kanzawa, Satoru Mitani, Zhiqiang Wei, Takeshi Takagi, Koji Katayama
  • Publication number: 20130112936
    Abstract: A variable resistance element including: a first electrode; a second electrode; and a variable resistance layer having a resistance value which reversibly changes according to electrical signals applied, wherein the variable resistance layer includes a first variable resistance layer comprising a first oxygen-deficient transition metal oxide, and a second variable resistance layer comprising a second transition metal oxide having a degree of oxygen deficiency lower than a degree of oxygen deficiency of the first transition metal oxide layer, the second electrode has a single needle-shaped part at the interface with the second variable resistance layer, and the second variable resistance layer is interposed between the first variable resistance layer and the second electrode, is in contact with the first variable resistance layer and the second electrode, and covers the needle-shaped part.
    Type: Application
    Filed: January 18, 2012
    Publication date: May 9, 2013
    Applicant: Panasonic Corporation
    Inventors: Zhiqiang WEI, Takeshi Takagi, Satoru Mitani, Yoshio Kawashima, Ichirou Takahashi
  • Patent number: 8405076
    Abstract: A nonvolatile memory element (100) includes a variable resistance layer (107) including a first metal oxide MOx and a second metal oxide MOy, and reaction energy of chemical reaction related to the first metal oxide, the second metal oxide, oxygen ions, and electrons is 2 eV or less. The chemical reaction is expressed by a formula 13, where a combination (MOx, MOy) of MOx and MOy is selected from a group including (Cr2O3, CrO3), (Co3O4, Co2O3), (Mn3O4, Mn2O3), (VO2, V2O5), (Ce2O3, CeO2), (W3O8, WO3), (Cu2O, CuO), (SnO, SnO2), (NbO2, Nb2O5), and (Ti2O3, TiO2).
    Type: Grant
    Filed: February 3, 2010
    Date of Patent: March 26, 2013
    Assignee: Panasonic Corporation
    Inventors: Takeki Ninomiya, Takeshi Takagi, Zhiqiang Wei
  • Publication number: 20120327702
    Abstract: A nonvolatile memory element includes: a first electrode layer; a second electrode layer; and a variable resistance layer which is placed between the electrode layers, and whose resistance state reversibly changes between a high resistance state and a low resistance state based on a polarity of a voltage applied between the electrode layers. The variable resistance layer is formed by stacking a first oxide layer including an oxide of a first transition metal and a second oxide layer including an oxide of a second transition metal which is different from the first transition metal. At least one of the following conditions is satisfied: (1) a dielectric constant of the second oxide layer is larger than a dielectric constant of the first oxide layer; and (2) a band gap of the second oxide layer is smaller than a band gap of the first oxide layer.
    Type: Application
    Filed: August 30, 2012
    Publication date: December 27, 2012
    Inventors: Takeshi Takagi, Zhiqiang Wei, Takeki Ninomiya, Shunsaku Muraoka, Yoshihiko Kanzawa
  • Patent number: 8338816
    Abstract: A nonvolatile memory element of the present invention comprises a first electrode (503); a second electrode (505); and a resistance variable layer (504) which is disposed between the first electrode (503) and the second electrode (505), a resistance value of the resistance variable layer being changeable in response to electric signals which are applied between the first electrode (503) and the second electrode (505), wherein the first electrode and the second electrode comprise materials which are made of different elements.
    Type: Grant
    Filed: March 31, 2008
    Date of Patent: December 25, 2012
    Assignee: Panasonic Corporation
    Inventors: Yoshihiko Kanzawa, Shunsaku Muraoka, Satoru Mitani, Zhiqiang Wei, Takeshi Takagi
  • Patent number: 8339835
    Abstract: A nonvolatile memory element includes a current controlling element having a non-linear current-voltage characteristic, a resistance variable element which changes reversibly between a low-resistance state and a high-resistance state in which a resistance value of the resistance variable element is higher than a resistance value of the resistance variable element in the low-resistance state, in response to voltage pulses applied, and a fuse. The current controlling element, the resistance variable element and the fuse are connected in series, and the fuse is configured to be blown when the current controlling element is substantially short-circuited.
    Type: Grant
    Filed: April 22, 2010
    Date of Patent: December 25, 2012
    Assignee: Panasonic Corporation
    Inventors: Zhiqiang Wei, Takeshi Takagi, Mitsuteru Iijima
  • Publication number: 20120319072
    Abstract: A manufacturing method for manufacturing, with a simple process, a non-volatile memory apparatus having a stable memory performance includes: (a) forming a stacking-structure body above a substrate by alternately stacking conductive layers comprising a transition metal and interlayer insulating films comprising an insulating material; (b) forming a contact hole penetrating through the stacking-structure body to expose part of each of the conductive layers; (c) forming variable resistance layers by oxidizing the part of each of the conductive layers, the part being exposed in the contact hole, and each of the variable resistance layers having a resistance value that reversibly changes according to an application of an electric signal; and (d) forming a pillar electrode in the contact hole by embedding a conductive material in the contact hole, the pillar electrode being connected to each of the variable resistance layers.
    Type: Application
    Filed: February 23, 2011
    Publication date: December 20, 2012
    Inventors: Zhiqiang Wei, Takeshi Takagi, Mitsuteru Iijima
  • Patent number: 8320159
    Abstract: Each of memory cells (MC) includes one transistor and one resistance variable element. The transistor includes a first main terminal, a second main terminal and a control terminal. The resistance variable element includes a first electrode, a second electrode and a resistance variable layer provided between the first electrode and the second electrode. A first main terminal of one of two adjacent memory cells is connected to a second main terminal of the other memory cell, to form a series path (SP) sequentially connecting main terminals of the plurality of memory cells in series.
    Type: Grant
    Filed: March 15, 2010
    Date of Patent: November 27, 2012
    Assignee: Panasonic Corporation
    Inventors: Zhiqiang Wei, Ryotaro Azuma, Takeshi Takagi, Mitsuteru Iijima, Yoshihiko Kanzawa
  • Patent number: 8279657
    Abstract: Provided is a nonvolatile memory element which is capable of performing a stable resistance change operation at a low breakdown voltage. A nonvolatile memory element (100) includes: a first electrode layer (103); a second electrode layer (105); and a variable resistance layer (104) which is placed between the electrodes (103 and 105), and whose resistance state reversibly changes between a high resistance state and a low resistance state based on a polarity of a voltage applied between the electrodes (103 and 105). The variable resistance layer (104) is formed by stacking a first oxide layer (104a) including an oxide of a first transition metal and a second oxide layer (104b) including an oxide of a second transition metal which is different from the first transition metal.
    Type: Grant
    Filed: December 4, 2009
    Date of Patent: October 2, 2012
    Assignee: Panasonic Corporation
    Inventors: Takeshi Takagi, Zhiqiang Wei, Takeki Ninomiya, Shunsaku Muraoka, Yoshihiko Kanzawa
  • Patent number: 8179713
    Abstract: A nonvolatile memory element comprises a first electrode (103), a second electrode (105), and a resistance variable layer (104) which is provided between the first electrode and the second electrode, and is configured to reversibly switch an interelectrode resistance value which is a resistance value between the first electrode and the second electrode, in response to an interelectrode voltage which is an electric potential of the second electrode on the basis of the first electrode, the resistance variable layer includes an oxygen-deficient transition metal oxide, the first electrode side and the second electrode side have an asymmetric structure, a portion of the resistance variable layer which is located at the first electrode side and a portion of the resistance variable layer which is located at the second electrode side are each configured to be selectively placed into one of a low-resistance state and a high-resistance state, so as to attain a stable state in three or more different interelectrode resi
    Type: Grant
    Filed: May 18, 2009
    Date of Patent: May 15, 2012
    Assignee: Panasonic Corporation
    Inventors: Yoshihiko Kanzawa, Satoru Mitani, Zhiqiang Wei, Takeshi Takagi
  • Publication number: 20120104351
    Abstract: A stacking structure in which a stacked body (21) including a first conductive layer (13), a semiconductor layer (17), and a second conductive layer (18) and an interlayer insulating film (16) are alternately stacked in parallel to a substrate, a plurality of columnar electrodes (12) arranged so as to penetrated through the stacking structure in a stacking direction, a variable resistance layer (14) which is disposed between the columnar electrode (12) and the first conductive layer (13) and which has a resistance value that reversibly changes according to an application of an electric signal are included. The variable resistance layer (14) is formed by oxidizing part of the first conductive layer (13). The variable resistance layer (14) and an insulating film for electrically separating the semiconductor layer (17) and the second conductive layer (18) from the columnar electrode (12) are simultaneously formed in a single oxidation process.
    Type: Application
    Filed: June 29, 2011
    Publication date: May 3, 2012
    Inventors: Zhiqiang Wei, Takeshi Takagi, Mitsuteru Iijima