Patents by Inventor Masahiko Hiratani

Masahiko Hiratani 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: 6867090
    Abstract: By using a solid solution of tantalum pentoxide and niobium pentoxide as a dielectric film installed between upper electrode and lower electrode in a capacitor which is used in a semiconductor device, the capacitor structure can be simplified to improve reliability of the semiconductor device while reducing the production cost thereof.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: March 15, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Masahiko Hiratani, Shinichiro Kimura, Tomoyuki Hamada
  • Publication number: 20040262642
    Abstract: In a method for manufacturing an FET having a gate insulation film with an SiO2 equivalent thickness of 2 nm or more and capable of suppressing the leak current to {fraction (1/100)} or less compared with existent SiO2 films, an SiO2 film of 0.5 nm or more is formed at a boundary between an Si substrate (polycrystalline silicon gate) and a high dielectric insulation film, and the temperature for forming the SiO2 film is made higher than the source-drain activating heat treatment temperature in the subsequent steps. As such, a shifting threshold voltage by the generation of static charges or lowering of a drain current caused by degradation of mobility can be prevented so as to reduce electric power consumption and increase current in a field effect transistor of a smaller size.
    Type: Application
    Filed: July 28, 2004
    Publication date: December 30, 2004
    Applicant: Renesas Technology Corporation
    Inventors: Yasuhiro Shimamoto, Katsunori Obata, Kazuyoshi Torii, Masahiko Hiratani
  • Patent number: 6833577
    Abstract: The present invention relates to a structure of a capacitor, in particular using niobium pentoxide, of a semiconductor capacitor memory device. Since niobium pentoxide has a low crystallization temperature of 600° C. or less, niobium pentoxide can suppress the oxidation of a bottom electrode and a barrier metal by heat treatment. However, according to heat treatment at low temperature, carbon incorporated from CVD sources into the film is not easily oxidized or removed. Therefore, a problem that leakage current increases arises. As an insulator film of a capacitor, a layered film composed of a niobium pentoxide film and a tantalum pentoxide film, or a layered film composed of niobium pentoxide films is used. By the use of the niobium pentoxide film, the dielectric constant of the capacitor can be made high and the crystallization temperature can be made low. By multiple-stage formation of the dielectric film, leakage current can be decreased.
    Type: Grant
    Filed: November 21, 2002
    Date of Patent: December 21, 2004
    Assignee: Renesas Technology Corporation
    Inventors: Yuichi Matsui, Masahiko Hiratani
  • Publication number: 20040232497
    Abstract: A memory cell capacitor (C3) of a DRAM is formed by use of a MIM capacitor which uses as its electrode a metal wiring line of the same layer (M3) as metal wiring lines within a logic circuit (LOGIC), thereby enabling reduction of process costs. Higher integration is achievable by forming the capacitor using a high dielectric constant material and disposing it above a wiring layer in which bit lines (BL) are formed. In addition, using 2T cells makes it possible to provide a sufficient signal amount even when letting them operate with a low voltage. By commonizing the processes for fabricating capacitors in analog (ANALOG) and memory (MEM), it is possible to realize a semiconductor integrated circuit with the logic, analog and memory mounted together on one chip at low costs.
    Type: Application
    Filed: June 24, 2004
    Publication date: November 25, 2004
    Inventors: Satoru Akiyama, Takao Watanabe, Yuichi Matsui, Masahiko Hiratani
  • Publication number: 20040212000
    Abstract: The present invention relates to a structure of a capacitor, in particular using niobium pentoxide, of a semiconductor capacitor memory device. Since niobium pentoxide has a low crystallization temperature of 600° C. or less, niobium pentoxide can suppress the oxidation of a bottom electrode and a barrier metal by heat treatment. However, according to heat treatment at low temperature, carbon incorporated from CVD sources into the film is not easily oxidized or removed. Therefore, a problem that leakage current increases arises. As an insulator film of a capacitor, a layered film composed of a niobium pentoxide film and a tantalum pentoxide film, or a layered film composed of niobium pentoxide films is used. By the use of the niobium pentoxide film, the dielectric constant of the capacitor can be made high and the crystallization temperature can be made low. By multiple-stage formation of the dielectric film, leakage current can be decreased.
    Type: Application
    Filed: May 26, 2004
    Publication date: October 28, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Yuichi Matsui, Masahiko Hiratani
  • Patent number: 6787451
    Abstract: In a method for manufacturing an FET having a gate insulation film with an SiO2 equivalent thickness of 2 nm or more and capable of suppressing the leak current to {fraction (1/100)} or less compared with existent SiO2 films, an SiO2 film of 0.5 nm or more is formed at a boundary between an Si substrate (polycrystalline silicon gate) and a high dielectric insulation film, and the temperature for forming the SiO2 film is made higher than the source-drain activating heat treatment temperature in the subsequent steps. As such, a shifting threshold voltage by the generation of static charges or lowering of a drain current caused by degradation of mobility can be prevented so as to reduce electric power consumption and increase current in a field effect transistor of a smaller size.
    Type: Grant
    Filed: August 13, 2002
    Date of Patent: September 7, 2004
    Assignee: Renesas Technology Corporation
    Inventors: Yasuhiro Shimamoto, Katsunori Obata, Kazuyoshi Torii, Masahiko Hiratani
  • Publication number: 20040171210
    Abstract: A process for forming the lower and upper electrodes of a high dielectric constant capacitor in a semiconductor device from an organoruthenium compound by chemical vapor deposition. This chemical vapor deposition technique employs an organoruthenium compound, an oxidizing gas, and a gas (such as argon) which is hardly adsorbed to the ruthenium surface or a gas (such as ethylene) which is readily adsorbed to the ruthenium surface. This process efficiently forms a ruthenium film with good conformality in a semiconductor device.
    Type: Application
    Filed: March 9, 2004
    Publication date: September 2, 2004
    Applicant: Renesas Technology Corporation
    Inventors: Yasuhiro Shimamoto, Masahiko Hiratani, Yuichi Matsui, Toshihide Nabatame
  • Patent number: 6743739
    Abstract: A process for forming the lower and upper electrodes of a high dielectric constant capacitor in a semiconductor device from an organoruthenium compound by chemical vapor deposition. This chemical vapor deposition technique employs an organoruthenium compound, an oxidizing gas, and a gas (such as argon) which is hardly adsorbed to the ruthenium surface or a gas (such as ethylene) which is readily adsorbed to the ruthenium surface. This process efficiently forms a ruthenium film with good conformality in a semiconductor device.
    Type: Grant
    Filed: March 21, 2002
    Date of Patent: June 1, 2004
    Assignee: Renesas Technology Corporation
    Inventors: Yasuhiro Shimamoto, Masahiko Hiratani, Yuichi Matsui, Toshihide Nabatame
  • Patent number: 6740901
    Abstract: A semiconductor integrated circuit in which the storage capacitor has an increased capacitance and a decreased leakage current. The storage capacitor is formed by the steps of: forming a polysilicon bottom electrode having semispherical silicon crystals formed thereon; performing plasma nitriding on the surface of said bottom electrode at a temperature lower than 550° C., thereby forming a film of silicon nitride having a film thickness smaller than 1.5 nm; and depositing a film of amorphous tantalum pentoxide and then crystallizing said amorphous tantalum pentoxide. The silicon nitride film has improved resistance to oxidation and also has a reduced leakage current. As a result, the polysilicon bottom electrode becomes resistant to oxidation and the storage capacitor increases in capacitance and decreases in leakage current.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: May 25, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Hiroshi Miki, Yasuhiro Shimamoto, Masahiko Hiratani, Tomoyuki Hamada
  • Patent number: 6720603
    Abstract: A disadvantage upon heat treatment in an oxygen atmosphere of a dielectric film formed on a lower electrode of capacitance device of DRAM that oxygen permeating the lower electrode oxidizes a barrier layer to form an oxide layer of high resistance and low dielectric constant is prevented. An Ru silicide layer is formed on the surface of a plug in a through hole formed below a lower electrode for an information storage capacitance device C and an Ru silicon nitride layer is formed further on the surface of the Ru silicide layer. Upon high temperature heat treatment in an oxygen atmosphere conducted in the step of forming a dielectric film on the lower electrode, the Ru silicon nitride layer is oxidized sacrificially into an Ru silicon oxynitride to prevent progress of oxidation in the Ru silicide layer.
    Type: Grant
    Filed: December 18, 2002
    Date of Patent: April 13, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Shinpei Iijima, Yuzuru Ohji, Masato Kunitomo, Masahiko Hiratani, Yuichi Matsui, Hiroyuki Ohta, Yukihiro Kumagai
  • Patent number: 6713343
    Abstract: An integrated semiconductor device has an improved reliability and is adapted to a higher degree of integration without reducing the accumulated electric charge of each information storage capacity element. The semiconductor device is provided with a DRAM having memory cells, each comprising an information storage capacity element C connected in series to a memory cell selection MISFET Qs formed on a main surface of a semiconductor substrate 1 and having a lower electrode 54, a capacity insulating film 58 and an upper electrode 59. The lower electrode 54 is made of ruthenium film oriented in a particular plane bearing, e.g., a (002) plane, and the capacity insulating film 58 is made of a polycrystalline tantalum film obtained by thermally treating an amorphous tantalum oxide film containing crystal of tantalum oxide in an as-deposited state for crystallization.
    Type: Grant
    Filed: March 17, 2003
    Date of Patent: March 30, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yasuhiro Sugawara, Shinpei Iijima, Yuzuru Oji, Naruhiko Nakanishi, Misuzu Kanai, Masahiko Hiratani
  • Patent number: 6693792
    Abstract: A capacitor having an equivalent thickness of 3.0 nm or less, with a sufficient static capacitance and less leakage current in a reduced size, constituted by stacking an interfacial film 21 having a physical thickness of 2.5 nm or more for suppressing tunnel leakage current and a high dielectric film 22 comprising tantalum pentaoxide on lower electrode 19, 20 comprising rugged polycrystal silicon film, the interfacial film 21 comprising a nitride film formed by an LPCVD method, for example, from Al2O3, a mixed phase of Al2O3 and SiO2, ZrSiO4, HfSiO4, a mixed phase of Y2O3 and SiO2, and a mixed phase of La2O3 and SiO2.
    Type: Grant
    Filed: April 11, 2003
    Date of Patent: February 17, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yasuhiro Shimamoto, Hiroshi Miki, Masahiko Hiratani
  • Patent number: 6664157
    Abstract: Plug electrodes of silicon are formed so as to be buried in through holes in a first insulating film, the plug electrodes being electrically connected to the source and drain regions of a MISFET on the main surface of a semiconductor substrate. Then, a second insulating film is deposited thereon and holes are formed therein such that the plug electrodes of silicon are exposed. A barrier film is formed on the surfaces of the silicon plugs, and in the holes a dielectric is formed to form lower electrodes of the capacitor elements and an upper electrode therefor.
    Type: Grant
    Filed: February 5, 2001
    Date of Patent: December 16, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Shinpei Iijima, Yoshitaka Nakamura, Masahiko Hiratani, Yuichi Matsui, Naruhiko Nakanishi
  • Publication number: 20030205752
    Abstract: A capacitor having an equivalent thickness of 3.0 nm or less, with a sufficient static capacitance and less leakage current in a reduced size, constituted by stacking an interfacial film 21 having a physical thickness of 2.5 nm or more for suppressing tunnel leakage current and a high dielectric film 22 comprising tantalum pentaoxide on lower electrode 19, 20 comprising rugged polycrystal silicon film, the interfacial film 21 comprising a nitride film formed by an LPCVD method, for example, from Al2O3, a mixed phase of Al2O3 and SiO2, ZrSiO4, HfSiO4, a mixed phase of Y2O3 and SiO2, and a mixed phase of La2O3 and SiO2.
    Type: Application
    Filed: April 11, 2003
    Publication date: November 6, 2003
    Inventors: Yasuhiro Shimamoto, Hiroshi Miki, Masahiko Hiratani
  • Publication number: 20030201485
    Abstract: By using a solid solution of tantalum pentoxide and niobium pentoxide as a dielectric film installed between upper electrode and lower electrode in a capacitor which is used in a semiconductor device, the capacitor structure can be simplified to improve reliability of the semiconductor device while reducing the production cost thereof.
    Type: Application
    Filed: April 24, 2003
    Publication date: October 30, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Masahiko Hiratani, Shinichiro Kimura, Tomoyuki Hamada
  • Publication number: 20030173614
    Abstract: Disclosed are a semiconductor integrated circuit device and a method of manufacturing the same capable of improving the characteristics of the semiconductor integrated circuit device by reducing a leakage current of a capacitor used in a DRAM memory cell. A data storage capacitor connected to a data transfer MISFET in a memory cell forming area via plugs is formed in the following manner. That is, a lower electrode composed of an Ru film is formed in a hole in a silicon oxide film, and then, a tantalum oxide film is deposited on the lower electrode. Thereafter, a first thermal treatment in an oxidizing atmosphere is performed to the film at a temperature sufficient to repair an oxygen defect and having no influence on the materials below the tantalum oxide film. Further, a second thermal treatment in an inactive atmosphere is performed at a temperature at which the tantalum oxide film is not completely crystallized (650° C.) and higher than that applied in the later process.
    Type: Application
    Filed: January 28, 2003
    Publication date: September 18, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Yoshitaka Nakamura, Isamu Asano, Shinpei Iijima, Masahiko Hiratani, Hiroshi Sakuma
  • Publication number: 20030151083
    Abstract: The present invention relates to a structure of a capacitor, in particular using niobium pentoxide, of a semiconductor capacitor memory device. Since niobium pentoxide has a low crystallization temperature of 600° C. or less, niobium pentoxide can suppress the oxidation of a bottom electrode and a barrier metal by heat treatment. However, according to heat treatment at low temperature, carbon incorporated from CVD sources into the film is not easily oxidized or removed. Therefore, a problem that leakage current increases arises. As an insulator film of a capacitor, a layered film composed of a niobium pentoxide film and a tantalum pentoxide film, or a layered film composed of niobium pentoxide films is used. By the use of the niobium pentoxide film, the dielectric constant of the capacitor can be made high and the crystallization temperature can be made low. By multiple-stage formation of the dielectric film, leakage current can be decreased.
    Type: Application
    Filed: November 21, 2002
    Publication date: August 14, 2003
    Inventors: Yuichi Matsui, Masahiko Hiratani
  • Publication number: 20030141533
    Abstract: Disclosed are a semiconductor integrated circuit device and a method of manufacturing the same capable of improving the characteristics of the semiconductor integrated circuit device by reducing a leakage current of a capacitor used in a DRAM memory cell. A data storage capacitor connected to a data transfer MISFET in a memory cell forming area via plugs is formed in the following manner. That is, a lower electrode composed of an Ru film is formed in a hole in a silicon oxide film, and then, a tantalum oxide film is deposited on the lower electrode. Thereafter, a first thermal treatment in an oxidizing atmosphere is performed to the film at a temperature sufficient to repair an oxygen defect and having no influence on the materials below the tantalum oxide film. Further, a second thermal treatment in an inactive atmosphere is performed at a temperature at which the tantalum oxide film is not completely crystallized (650° C.) and higher than that applied in the later process.
    Type: Application
    Filed: January 28, 2003
    Publication date: July 31, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Yoshitaka Nakamura, Isamu Asano, Shinpei Iijima, Masahiko Hiratani, Hiroshi Sakuma
  • Publication number: 20030129806
    Abstract: A semiconductor integrated circuit in which the storage capacitor has an increased capacitance and a decreased leakage current. The storage capacitor is formed by the steps of: forming a polysilicon bottom electrode having semispherical silicon crystals formed thereon; performing plasma nitriding on the surface of said bottom electrode at a temperature lower than 550° C., thereby forming a film of silicon nitride having a film thickness smaller than 1.5 nm; and depositing a film of amorphous tantalum pentoxide and then crystallizing said amorphous tantalum pentoxide. The silicon nitride film has improved resistance to oxidation and also has a reduced leakage current. As a result, the polysilicon bottom electrode becomes resistant to oxidation and the storage capacitor increases in capacitance and decreases in leakage current.
    Type: Application
    Filed: December 2, 2002
    Publication date: July 10, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Hiroshi Miki, Yasuhiro Shimamoto, Masahiko Hiratani, Tomoyuki Hamada
  • Patent number: 6583023
    Abstract: A capacitor having an equivalent thickness of 3.0 nm or less, with a sufficient static capacitance and less leakage current in a reduced size, constituted by stacking an interfacial film 21 having a physical thickness of 2.5 nm or more for suppressing tunnel leakage current and a high dielectric film 22 comprising tantalum pentaoxide on lower electrode 19, 20 comprising rugged polycrystal silicon film, the interfacial film 21 comprising a nitride film formed by an LPCVD method, for example, from Al2O3, a mixed phase of Al2O3 and SiO2, ZrSiO4, HfSiO4, a mixed phase of Y2O3 and SiO2, and a mixed phase of La2O3 and SiO2.
    Type: Grant
    Filed: April 10, 2002
    Date of Patent: June 24, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Yasuhiro Shimamoto, Hiroshi Miki, Masahiko Hiratani