Patents by Inventor Yoshio Kawashima

Yoshio Kawashima 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: 20120097915
    Abstract: There are provided a resistance variable nonvolatile memory device which changes its resistance stably at low voltages and is suitable for a miniaturized configuration, and a manufacturing method thereof. The nonvolatile memory device comprises: a substrate (100); a first electrode (101); an interlayer insulating layer (102); a memory cell hole (103) formed in the interlayer insulating layer; a first resistance variable layer (104a) formed in at least a bottom portion of the memory cell hole and connected to the first electrode; a second resistance variable layer (104b) formed inside the memory cell hole (103) and located on the first resistance variable layer (104a); and a second electrode (105); the first resistance variable layer (104a) and the second resistance variable layer (104b) respectively comprising metal oxides of the same kind; and the first resistance variable layer (104a) having a higher oxygen content than the second resistance variable layer (104b).
    Type: Application
    Filed: June 30, 2009
    Publication date: April 26, 2012
    Inventors: Takumi Mikawa, Yoshio Kawashima, Atsushi Himeno
  • Publication number: 20120091425
    Abstract: A nonvolatile memory device (10A) comprises an upper electrode layer (2); a lower electrode layer (4); a resistance variable layer (3) sandwiched between the upper electrode layer (2) and the lower electrode layer (4); and a charge diffusion prevention mask (1A) formed on a portion of the upper electrode layer (2); wherein the resistance variable layer (3) includes a first film comprising oxygen-deficient transition metal oxide and a second film comprising oxygen-deficient transition metal oxide which is higher in oxygen content than the first film; at least one of the upper electrode layer (2) and the lower electrode layer (4) comprises a simple substance or alloy of a platinum group element; and the charge diffusion prevention mask (1A) is insulative, and is lower in etching rate of dry etching than the upper electrode layer (2) and the lower electrode layer (4).
    Type: Application
    Filed: June 16, 2010
    Publication date: April 19, 2012
    Inventors: Yoshio Kawashima, Takumi Mikawa
  • Publication number: 20120068148
    Abstract: A variable resistance nonvolatile memory element capable of suppressing a variation in resistance values is provided.
    Type: Application
    Filed: March 7, 2011
    Publication date: March 22, 2012
    Inventors: Yoshio Kawashima, Takumi Mikawa, Yukio Hayakawa
  • Publication number: 20120063201
    Abstract: A nonvolatile memory element which can be initialized at low voltage includes a variable resistance layer (116) located between a lower electrode (105) and an upper electrode (107) and having a resistance value that reversibly changes based on electrical signals applied between these electrodes. The variable resistance layer (116) includes at least two layers: a first variable resistance layer (1161) including a first transition metal oxide (116b); and a second variable resistance layer (1162) including a second transition metal oxide (116a) and a third transition metal oxide (116c). The second transition metal oxide (116a) has an oxygen deficiency higher than either oxygen deficiency of the first transition metal oxide (116b) or the third transition metal oxide (116c), and the second transition metal oxide (116a) and the third transition metal oxide (116c) are in contact with the first variable resistance layer (1161).
    Type: Application
    Filed: March 16, 2011
    Publication date: March 15, 2012
    Inventors: Yukio Hayakawa, Takumi Mikawa, Yoshio Kawashima, Takeki Ninomiya
  • Publication number: 20110233511
    Abstract: A nonvolatile memory element (10) of the present invention comprises a substrate (11); a lower electrode layer (15) and a resistive layer (16) sequentially formed on the substrate (11); a resistance variable layer (31) formed on the resistive layer (16); a wire layer (20) formed above the lower electrode layer (15); an interlayer insulating layer (17) disposed between the substrate (11) and the wire layer (20) and covering at least the lower electrode layer (15) and the resistive layer (16), the interlayer insulating layer being provided with a contact hole (26) extending from the wire layer (20) to the resistance variable layer (31); and an upper electrode layer (19) formed inside the contact hole (26) such that the upper electrode layer is connected to the resistance variable layer (31) and to the wire layer (20); resistance values of the resistance variable layer (31) changing reversibly in response to electric pulses applied between the lower electrode layer (15) and the upper electrode layer (19).
    Type: Application
    Filed: December 4, 2009
    Publication date: September 29, 2011
    Inventors: Yoshio Kawashima, Takumi Mikawa, Zhiqiang Wei, Atsushi Himeno
  • Publication number: 20110220863
    Abstract: To realize miniaturization and increased capacity of memories by lowering break voltage for causing resistance change and suppressing variation in break voltage. The nonvolatile memory device (10) in the present invention includes: a lower electrode (105) formed above a substrate (100); a first variable resistance layer (106a) formed above the lower electrode (105) and comprising a transitional metal oxide; a second variable resistance layer (106b) formed above the first variable resistance layer (106a) and comprising a transitional metal oxide having higher oxygen content than the transitional metal oxide of the first variable resistance layer (106a); and an upper electrode (107) formed above the second variable resistance layer (106b), wherein a step (106ax) is formed in an interface between the first variable is resistance layer (106a) and the second variable resistance layer (106b).
    Type: Application
    Filed: September 13, 2010
    Publication date: September 15, 2011
    Inventors: Takumi Mikawa, Yoshio Kawashima
  • Publication number: 20110220861
    Abstract: A nonvolatile semiconductor memory device which can achieve miniaturization and a larger capacity in a cross-point structure in which memory cells are formed inside contact holes at cross points of word lines and bit lines, respectively, and a manufacturing method thereof are provided.
    Type: Application
    Filed: July 16, 2009
    Publication date: September 15, 2011
    Inventors: Atsushi Himeno, Takumi Mikawa, Yoshio Kawashima
  • Publication number: 20110220862
    Abstract: A resistance variable element (100) used in a through-hole cross-point structure memory device, according to the present invention, and a resistance variable memory device including the resistance variable element, includes a substrate (7) and an interlayer insulating layer (3) formed on the substrate, and have a configuration in which a through-hole (4) is formed to penetrate the interlayer insulating layer, a first resistance variable layer (2) comprising transition metal oxide is formed outside the through-hole, a second resistance variable layer (5) comprising transition metal oxide is formed inside the through-hole, the first resistance variable layer is different in resistivity from the second resistance variable layer, and the first resistance variable layer and the second resistance variable layer are in contact with each other only in an opening (20) of the through-hole which is closer to the substrate.
    Type: Application
    Filed: July 12, 2010
    Publication date: September 15, 2011
    Inventors: Koji Arita, Takumi Mikawa, Atsushi Himeno, Yoshio Kawashima, Kenji Tominaga
  • Patent number: 8013711
    Abstract: A method for manufacturing a variable resistance element includes the steps of: depositing a variable resistance material (106) in a contact hole (105), which is formed on an interlayer insulating layer (104) on a substrate and has a lower electrode (103) at a bottom portion thereof, such that an upper surface of the variable resistance material (106) in the contact hole (105) is located lower than an upper surface of the interlayer insulating layer (104); depositing an upper electrode material on the deposited variable resistance material (106) such that an upper surface of the upper electrode material in the contact hole (105) is located higher than the upper surface of the interlayer insulating layer (104); and element-isolating by a CMP the variable resistance element including the variable resistance material (106) and the upper electrode material.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: September 6, 2011
    Assignee: Panasonic Corporation
    Inventors: Zhiqiang Wei, Takumi Mikawa, Takeshi Takagi, Yoshio Kawashima
  • Patent number: 7981760
    Abstract: A method for manufacturing a nonvolatile storage element that minimizes shape shift between an upper electrode and a lower electrode, and which includes: depositing, in sequence, a connecting electrode layer which is conductive, a lower electrode layer and a variable resistance layer which are made of a non-noble metal nitride and are conductive, an upper electrode layer made of noble metal, and a mask layer; forming the mask layer into a predetermined shape; forming the upper electrode layer, the variable resistance layer, and the lower electrode layer into the predetermined shape by etching using the mask layer as a mask; and removing, simultaneously, the mask and a region of the connecting electrode layer that has been exposed by the etching.
    Type: Grant
    Filed: May 7, 2009
    Date of Patent: July 19, 2011
    Assignee: Panasonic Corporation
    Inventors: Yoshio Kawashima, Takumi Mikawa, Takeshi Takagi, Koji Arita
  • Patent number: 7960770
    Abstract: A lower electrode (22) is provided on a semiconductor chip substrate (26). A lower electrode (22) is covered with a first interlayer insulating layer (27) from above. A first contact hole (28) is provided on the lower electrode (22) to penetrate through the first interlayer insulating layer (27). A low-resistance layer (29) forming the resistance variable layer (24) is embedded to fill the first contact hole (28). A high-resistance layer (30) is provided on the first interlayer insulating layer (27) and the low-resistance layer (29). The resistance variable layer (24) is formed by a multi-layer resistance layer including a single layer of the high-resistance layer (30) and a single layer of the low-resistance layer (29). The low-resistance layer (29) forming the memory portion (25) is isolated from at least its adjacent memory portion (25).
    Type: Grant
    Filed: October 12, 2007
    Date of Patent: June 14, 2011
    Assignee: Panasonic Corporation
    Inventors: Takumi Mikawa, Takeshi Takagi, Yoshio Kawashima, Koji Arita
  • Publication number: 20110114912
    Abstract: A nonvolatile semiconductor memory device (100) comprises a substrate (102) provided with a transistor (101); a first interlayer insulating layer (103) formed over the substrate to cover the transistor; a first contact plug (104) formed in the first interlayer insulating layer and electrically connected to either of a drain electrode (101a) or a source electrode (101b) of the transistor, and a second contact plug (105) formed in the first interlayer insulating layer and electrically connected to the other of the drain electrode or the source electrode of the transistor; a resistance variable layer (106) formed to cover a portion of the first contact plug; a first wire (107) formed on the resistance variable layer; and a second wire (108) formed to cover a portion of the second contact plug; an end surface of the resistance variable layer being coplanar with an end surface of the first wire.
    Type: Application
    Filed: February 9, 2009
    Publication date: May 19, 2011
    Inventors: Takumi Mikawa, Yoshio Kawashima, Koji Arita, Takeki Ninomiya
  • Patent number: 7919774
    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: Grant
    Filed: February 19, 2010
    Date of Patent: April 5, 2011
    Assignee: Panasonic Corporation
    Inventors: Yoshio Kawashima, Takeshi Takagi, Takumi Mikawa, Zhiqiang Wei
  • Publication number: 20100283026
    Abstract: A first wire layer (19) including first memory wires (12) is connected to a second wire layer (20) including second memory wires (17) via first contacts (21) penetrating a first interlayer insulating layer (13). The first wire layer (13) is connected to and led out to upper wires (22) via second contacts (26) connected to the second wire layer (20) and penetrating the second interlayer insulating layer (18). The first contacts (21) penetrate semiconductor layer (17b) or insulator layer (17c) of the second wire layer (20).
    Type: Application
    Filed: December 26, 2008
    Publication date: November 11, 2010
    Inventors: Takumi Mikawa, Yoshio Kawashima, Ryoko Miyanaga
  • Publication number: 20100264392
    Abstract: A nonvolatile memory device includes via holes (12) formed at cross sections where first wires (11) cross second wires (14), respectively, and current control elements (13) each including a current control layer (13b), a first electrode layer (13a) and a second electrode layer (13c) such that the current control layer (13b) is sandwiched between the first electrode layer (13a) and the second electrode layer (13c), in which resistance variable elements (15) are provided inside the via holes (12), respectively, the first electrode layer (13a) is disposed so as to cover the via hole (12), the current control layer (13b) is disposed so as to cover the first electrode layer (13a), the second electrode layer (13c) is disposed on the current control layer (13b), a wire layer (14a) of the second wire is disposed on the second electrode layer (13c), and the second wires (14) each includes the current control layer (13b), the second electrode layer (13c) and the wire layer (14a) of the second wire.
    Type: Application
    Filed: November 14, 2008
    Publication date: October 21, 2010
    Inventors: Yoshio Kawashima, Takumi Mikawa, Ryoko Miyanaga, Takeshi Takagi
  • Publication number: 20100237313
    Abstract: A nonvolatile semiconductor memory device of the present invention includes a substrate (1), first wires (2), memory cells each including a resistance variable element (5) and a portion of a diode element (6), second wires (11) which respectively cross the first wires (2) to be perpendicular to the first wires (2) and each of which contains a remaining portion of the diode element (6), and upper wires (13) formed via an interlayer insulating layer (12), respectively, and the first wires (2) are connected to the upper wires (13) via first contacts (14), respectively, and the second wires (11) are connected to the upper wires (13) via second contacts (15), respectively.
    Type: Application
    Filed: October 22, 2008
    Publication date: September 23, 2010
    Inventors: Takumi Mikawa, Yoshio Kawashima, Ryoko Miyanaga
  • Publication number: 20100225438
    Abstract: A method for manufacturing a variable resistance element includes the steps of: depositing a variable resistance material (106) in a contact hole (105), which is formed on an interlayer insulating layer (104) on a substrate and has a lower electrode (103) at a bottom portion thereof, such that an upper surface of the variable resistance material (106) in the contact hole (105) is located lower than an upper surface of the interlayer insulating layer (104); depositing an upper electrode material on the deposited variable resistance material (106) such that an upper surface of the upper electrode material in the contact hole (105) is located higher than the upper surface of the interlayer insulating layer (104); and element-isolating by a CMP the variable resistance element including the variable resistance material (106) and the upper electrode material.
    Type: Application
    Filed: February 27, 2007
    Publication date: September 9, 2010
    Applicant: PANASONIC CORPORATION
    Inventors: Zhiqiang Wei, Takumi Mikawa, Takeshi Takagi, Yoshio Kawashima
  • Publication number: 20100200852
    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: February 19, 2010
    Publication date: August 12, 2010
    Applicant: Panasonic Corporation
    Inventors: Yoshio Kawashima, Takeshi Takagi, Takumi Mikawa, Zhiqiang Wei
  • Publication number: 20100190313
    Abstract: A method for manufacturing a nonvolatile storage element that minimizes shape shift between an upper electrode and a lower electrode, and which includes: depositing, in sequence, a connecting electrode layer which is conductive, a lower electrode layer and a variable resistance layer which are made of a non-noble metal nitride and are conductive, an upper electrode layer made of noble metal, and a mask layer; forming the mask layer, into a predetermined shape; forming the upper electrode layer, the variable resistance layer, and the lower electrode layer into the predetermined shape by etching using the mask layer as a mask; and removing, simultaneously, the mask and a region of the connecting electrode layer that has been exposed by the etching.
    Type: Application
    Filed: May 7, 2009
    Publication date: July 29, 2010
    Inventors: Yoshio Kawashima, Takumi Mikawa, Takeshi Takagi, Koji Arita
  • Publication number: 20100090193
    Abstract: A lower electrode (22) is provided on a semiconductor chip substrate (26). A lower electrode (22) is covered with a first interlayer insulating layer (27) from above. A first contact hole (28) is provided on the lower electrode (22) to penetrate through the first interlayer insulating layer (27). A low-resistance layer (29) forming the resistance variable layer (24) is embedded to fill the first contact hole (28). A high-resistance layer (30) is provided on the first interlayer insulating layer (27) and the low-resistance layer (29). The resistance variable layer (24) is formed by a multi-layer resistance layer including a single layer of the high-resistance layer (30) and a single layer of the low-resistance layer (29). The low-resistance layer (29) forming the memory portion (25) is isolated from at least its adjacent memory portion (25).
    Type: Application
    Filed: October 12, 2007
    Publication date: April 15, 2010
    Inventors: Takumi Mikawa, Takeshi Takagi, Yoshio Kawashima, Koji Arita