Patents by Inventor Wensheng Wang

Wensheng Wang 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: 8748962
    Abstract: A semiconductor device includes a capacitor dielectric film formed on a lower electrode and made of a ferroelectric material, and an upper electrode formed on a capacitor dielectric film, wherein the lower electrode includes a lowest conductive layer and an upper conductive layer, the lowest conductive layer being made of a noble metal other than iridium, and the upper conductive layer being formed on the lowest conductive layer and made of a conductive material, which is different from a material for the lowest conductive layer, and which is other than platinum.
    Type: Grant
    Filed: October 22, 2012
    Date of Patent: June 10, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8729707
    Abstract: A method of manufacturing a semiconductor device includes forming an insulating film over a semiconductor substrate, forming a capacitor including a lower electrode, a capacitor dielectric film including a ferroelectric material, and an upper electrode over the insulating film, forming a first protective insulating film over a side surface and upper surface of the capacitor by a sputtering method, and forming a second protective insulating film over the first protective insulating film by an atomic layer deposition method.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: May 20, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8664011
    Abstract: An upper electrode of a ferroelectric capacitor has a first layer formed of a first oxide expressed by a chemical formula AOx1 (A: metal, O: oxygen) using a stoichiometric composition parameter x1, and expressed by a chemical formula AOx2 using a actual composition parameter x2, and a second layer formed of a second oxide, formed on the first layer, expressed by a chemical formula BOy1 (B: metal) using a stoichiometric composition parameter y1 and expressed by a chemical formula BOy2 using a actual composition parameter y2, which includes at least one of stone-wall crystal and column crystal.
    Type: Grant
    Filed: February 28, 2013
    Date of Patent: March 4, 2014
    Assignee: Fujitsu Limited
    Inventor: Wensheng Wang
  • Patent number: 8659062
    Abstract: A lower electrode film is formed above a substrate. A ferroelectric film is formed above the lower electrode film. An amorphous intermediate film of a perovskite-type conductive oxide is formed above the ferroelectric film. A first upper electrode film comprising oxide of at least one metal selected from a group of Pt, Pd, Rh, Ir, Ru, and Os is formed on the intermediate film. The intermediate film is crystallized by carrying out a first heat treatment in an atmosphere containing an oxidizing gas after the formation of the first upper electrode film. After the first heat treatment, a second upper electrode film comprising oxide of at least one metal selected from a group of Pt, Pd, Rh, Ir, Ru, and Os is formed on the first upper electrode film, at a temperature lower than the growth temperature for the first upper electrode film.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: February 25, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8652854
    Abstract: There are provided a capacitor lower electrode formed on an adhesive layer, whose surface roughness is 0.79 nm or less, and having a (111) orientation that is inclined from a perpendicular direction to an upper surface of a substrate by 2.3° or less, a ferroelectric layer having a structure the (111) orientation of which is inclined from the perpendicular direction to the upper surface of the substrate by 3.5° or less, and a capacitor upper electrode.
    Type: Grant
    Filed: March 12, 2012
    Date of Patent: February 18, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Tomohiro Takamatsu, Junichi Watanabe, Ko Nakamura, Wensheng Wang, Naoyuki Sato, Aki Dote, Kenji Nomura, Yoshimasa Horii, Masaki Kurasawa, Kazuaki Takai
  • Publication number: 20140030824
    Abstract: A ferroelectric memory is constituted to comprise a capacitor being formed above a semiconductor substrate (61) and having a ferroelectric film (78) held between a lower electrode (77) and an upper electrode (79), a W plug (72b) electrically connected on its upper surface with the lower electrode (77), and a protective film (76) formed between the W plug (72b) and the lower electrode (77) and made of at least any one kind out of a conductive oxide, a conductive nitride, and a conductive oxynitride. The protective film (76) prevents an orientation of the lower electrode (77) from depending on the W plug (72b), thereby making the orientation of the lower electrode (77) uniform. Accordingly, it is possible to make an orientation of the ferroelectric film (78) to be formed on the lower electrode (77) uniform, which enables to improve an electric characteristic of the ferroelectric capacitor.
    Type: Application
    Filed: September 30, 2013
    Publication date: January 30, 2014
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Wensheng Wang
  • Patent number: 8629487
    Abstract: A semiconductor device includes a substrate and a ferroelectric capacitor including a lower electrode, a ferroelectric film, and an upper electrode. The upper electrode includes a first layer formed of an oxide whose stoichiometric composition is expressed as AOx1 and whose actual composition is expressed as AOx2; a second layer formed on the first layer and formed of an oxide whose stoichiometric composition is expressed as BOy1 and whose actual composition is expressed as BOy2; and a metal layer formed on the second layer. The second layer is higher in ratio of oxidation than the first layer. The composition parameters x1, x2, y1, and y2 satisfy y2/y1>x2/x1, and the second layer includes an interface layer of the stoichiometric composition formed at an interface with the metal layer. The interface layer is higher in ratio of oxidation than the rest of the second layer.
    Type: Grant
    Filed: February 1, 2013
    Date of Patent: January 14, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8614104
    Abstract: A ferroelectric capacitor is formed over a semiconductor substrate (10), and thereafter, interlayer insulating films (48, 50, 52) covering the ferroelectric capacitor are formed. Next, a contact hole (54) reaching a top electrode (40) is formed in the interlayer insulating films (48, 50, 52). Next, a wiring (58) electrically connected to the top electrode (40) through the contact hole (54) is formed on the interlayer insulating films (48, 50, 52). At the time of forming the top electrode (40), conductive oxide films (40a, 40b) are formed, and then a cap film (40c) composed of a noble metal exhibiting less catalytic action than Pt and having a thickness of 150 nm or less is formed on the conductive oxide films (40a, 40b).
    Type: Grant
    Filed: March 14, 2011
    Date of Patent: December 24, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8609440
    Abstract: A semiconductor device includes a substrate and a ferroelectric capacitor including a lower electrode, a ferroelectric film, and an upper electrode. The upper electrode includes a first layer formed of an oxide whose stoichiometric composition is expressed as AOx1 and whose actual composition is expressed as AOx2; a second layer formed on the first layer and formed of an oxide whose stoichiometric composition is expressed as BOy1 and whose actual composition is expressed as BOy2; and a metal layer formed on the second layer. The second layer is higher in ratio of oxidation than the first layer. The composition parameters x1, x2, y1, and y2 satisfy y2/y1>x2/x1, and the second layer includes an interface layer of the stoichiometric composition formed at an interface with the metal layer. The interface layer is higher in ratio of oxidation than the rest of the second layer.
    Type: Grant
    Filed: February 1, 2013
    Date of Patent: December 17, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8551836
    Abstract: A method of manufacturing a semiconductor device includes forming an insulating film over a semiconductor substrate, forming a capacitor including a lower electrode, a capacitor dielectric film including a ferroelectric material, and an upper electrode over the insulating film, forming a first protective insulating film over a side surface and upper surface of the capacitor by a sputtering method, and forming a second protective insulating film over the first protective insulating film by an atomic layer deposition method.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: October 8, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8513100
    Abstract: In a semiconductor device manufacturing method, an amorphous or microcrystalline metal oxide film is formed over a first metal film which is preferentially oriented along a predetermined crystal plane. After that, a ferroelectric film is formed by a MOCVD method. When the ferroelectric film is formed, the metal oxide film formed over the first metal film is reduced to a second metal film and the ferroelectric film is formed over the second metal film. When the ferroelectric film is formed, the amorphous or microcrystalline metal oxide film is apt to be reduced uniformly. As a result, the second metal film the orientation of which is good is obtained and the ferroelectric film the orientation of which is good is formed over the second metal film. After the ferroelectric film is formed, an upper electrode is formed over the ferroelectric film.
    Type: Grant
    Filed: December 21, 2011
    Date of Patent: August 20, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8497537
    Abstract: A semiconductor device has a ferro-electric capacitor with small leak current and less process deterioration even upon miniaturization.
    Type: Grant
    Filed: May 28, 2008
    Date of Patent: July 30, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Wensheng Wang, Ko Nakamura
  • Patent number: 8497181
    Abstract: An FeRAM is produced by a method including the steps of forming a lower electrode layer, forming a first ferroelectric film on the lower electrode layer, forming on the first ferroelectric film a second ferroelectric film in an amorphous state containing iridium inside, thermally treating the second ferroelectric film in an oxidizing atmosphere to crystallize the second ferroelectric film and to cause iridium in the second ferroelectric film to diffuse into the first ferroelectric film, forming an upper electrode layer on the second ferroelectric film, and processing each of the upper electrode layer, the second ferroelectric film, the first ferroelectric film, and the lower electrode layer to form the capacitor structure. With such a structure, the inversion charge amount in a ferroelectric capacitor structure is improved without increasing the leak current pointlessly, and a high yield can be assured, thereby realizing a highly reliable FeRAM.
    Type: Grant
    Filed: December 16, 2012
    Date of Patent: July 30, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8441101
    Abstract: Ferroelectric capacitors (42) are formed over a semiconductor substrate (10), then, a barrier film (46) directly covering the ferroelectric capacitors (42) is formed. Thereafter, wirings (56a etc.) connected to the ferroelectric capacitors (42) are formed. Further, a barrier film (58) is formed at a position higher than the wirings (56a etc.). In forming the barrier film (46), a film stack is formed, the film stack including at least two kinds of diffusion preventive films (46a and 46b) having different components and preventing diffusion of hydrogen or water.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: May 14, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8405188
    Abstract: An upper electrode of a ferroelectric capacitor has a first layer formed of a first oxide expressed by a chemical formula AOx1 (A: metal, O: oxygen) using a stoichiometric composition parameter x1, and expressed by a chemical formula AOx2 using a actual composition parameter x2, and a second layer formed of a second oxide, formed on the first layer, expressed by a chemical formula BOy1 (B: metal) using a stoichiometric composition parameter y1 and expressed by a chemical formula BOy2 using a actual composition parameter y2, which includes at least one of stone-wall crystal and column crystal.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: March 26, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8390045
    Abstract: A semiconductor device includes a substrate and a ferroelectric capacitor including a lower electrode, a ferroelectric film, and an upper electrode. The upper electrode includes a first layer formed of an oxide whose stoichiometric composition is expressed as AOx1 and whose actual composition is expressed as AOx2; a second layer formed on the first layer and formed of an oxide whose stoichiometric composition is expressed as BOy1 and whose actual composition is expressed as BOy2; and a metal layer formed on the second layer. The second layer is higher in ratio of oxidation than the first layer. The composition parameters x1, x2, y1, and y2 satisfy y2/y1>x2/x1, and the second layer includes an interface layer of the stoichiometric composition formed at an interface with the metal layer. The interface layer is higher in ratio of oxidation than the rest of the second layer.
    Type: Grant
    Filed: August 25, 2009
    Date of Patent: March 5, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8389403
    Abstract: According to one embodiment, after forming transistors on a semiconductor substrate, a stopper layer and an interlayer insulating film are formed. Then, a contact hole is formed in the interlayer insulating film and a copper film is formed on the interlayer insulating film to bury the inside of the contact hole with copper. After that, the copper film on the interlayer insulating film is removed by low-pressure CMP polishing or ECMP polishing to planarize a surface thereof to form plugs. Thereafter, a barrier metal, a lower electrode, a ferroelectric film, and an upper electrode are formed. In this manner, a semiconductor device (FeRAM) having a ferroelectric capacitor is formed.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: March 5, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8373212
    Abstract: The semiconductor device has an insulation layer formed over a semiconductor substrate, a conductor plug 46 buried in the insulation layer, a capacitor formed above the insulation layer and the conductor plug and including a lower electrode formed of the first conduction film and the second conduction film formed over the first conduction film and formed of Pt, Pt alloy, Pd or Pd alloy, a capacitor dielectric film formed of a ferroelectric or a high dielectric formed over the lower electrode and an upper electrode formed over the capacitor dielectric film, the capacitor dielectric film contains a first element of Pb or Bi, and the concentration peak of the first element diffused in the lower electrode from the capacitor dielectric film positioning in the interface between the first conduction film and the second conduction film.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: February 12, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8367428
    Abstract: The present invention provides a semiconductor device which is characterized as follows. The semiconductor device includes: an interlayer insulating film formed above a semiconductor substrate and provided with a hole above an impurity diffusion region; a conductive plug formed in the hole and electrically connected to the impurity diffusion region; a conductive oxygen barrier film formed on the conductive plug and the interlayer insulating film around the conductive plug; a conductive anti-diffusion film formed on the conductive oxygen barrier film; and a capacitor that has a lower electrode which is formed on the conductive anti-diffusion film and which exposes platinum or palladium on the upper surface, a capacitor dielectric film made of a ferroelectric material, and an upper electrode. The conductive anti-diffusion film is made of a non-oxide conductive material for preventing the diffusion of the constituent element of the capacitor dielectric film.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: February 5, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang
  • Patent number: 8357585
    Abstract: An FeRAM is produced by a method including the steps of forming a lower electrode layer (24), forming a first ferroelectric film (25a) on the lower electrode layer (24), forming on the first ferroelectric film (25a) a second ferroelectric film (25b) in an amorphous state containing iridium inside, thermally treating the second ferroelectric film (25b) in an oxidizing atmosphere to crystallize the second ferroelectric film (25b) and to cause iridium in the second ferroelectric film (25b) to diffuse into the first ferroelectric film (25a), forming an upper electrode layer (26) on the second ferroelectric film (25b), and processing each of the upper electrode layer (26), the second ferroelectric film (25b), the first ferroelectric film (25a), and the lower electrode layer (24) to form the capacitor structure.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: January 22, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Wensheng Wang