Patents by Inventor Naoto Fujishima

Naoto Fujishima 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: 20240079275
    Abstract: A gate insulating film has a multilayer structure including a SiO2 film, a LaAlO3 film, and an Al2O3 film that are sequentially stacked, relative permittivity of the gate insulating film being optimized by the LaAlO3 film. In forming the LaAlO3 film constituting the gate insulating film, a La2O3 film and an Al2O3 film are alternately deposited repeatedly using an ALD method. The La2O3 film is deposited first, whereby during a POA performed thereafter, a sub-oxide of the surface of the SiO2 film is removed by a cleaning effect of lanthanum atoms in the La2O3 film. A temperature of the POA is suitably set in a range from 700 degrees C. to less than 900 degrees C.
    Type: Application
    Filed: April 27, 2023
    Publication date: March 7, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi TSUJI, Yuichi ONOZAWA, Naoto FUJISHIMA, Linhua HUANG, Johnny Kin On SIN
  • Patent number: 9892919
    Abstract: A first nickel film is deposited inside a contact hole of an interlayer dielectric formed on an n+-type SiC substrate. Irradiation with a first laser is carried out, forming an Ohmic contact with a silicon carbide semiconductor. A second nickel film and a front surface electrode film are deposited on the first nickel film, forming a source electrode. The back surface of the n+-type SiC substrate is ground, and a third nickel film is formed on the ground back surface of the n+-type SiC substrate. Irradiation with a second laser is carried out, forming an Ohmic contact with the silicon carbide semiconductor. A fourth nickel film and a back surface electrode film are deposited on the third nickel film, forming a drain electrode. By so doing, it is possible to prevent electrical characteristic deterioration of a semiconductor device, and to prevent warping and cracking of a wafer.
    Type: Grant
    Filed: April 9, 2015
    Date of Patent: February 13, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Haruo Nakazawa, Masaaki Tachioka, Naoto Fujishima, Masaaki Ogino, Tsunehiro Nakajima, Kenichi Iguchi
  • Publication number: 20150214053
    Abstract: A first nickel film is deposited inside a contact hole of an interlayer dielectric formed on an n+-type SiC substrate. Irradiation with a first laser is carried out, forming an Ohmic contact with a silicon carbide semiconductor. A second nickel film and a front surface electrode film are deposited on the first nickel film, forming a source electrode. The back surface of the n+-type SiC substrate is ground, and a third nickel film is formed on the ground back surface of the n+-type SiC substrate. Irradiation with a second laser is carried out, forming an Ohmic contact with the silicon carbide semiconductor. A fourth nickel film and a back surface electrode film are deposited on the third nickel film, forming a drain electrode. By so doing, it is possible to prevent electrical characteristic deterioration of a semiconductor device, and to prevent warping and cracking of a wafer.
    Type: Application
    Filed: April 9, 2015
    Publication date: July 30, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Haruo NAKAZAWA, Masaaki TACHIOKA, Naoto FUJISHIMA, Masaaki OGINO, Tsunehiro NAKAJIMA, Kenichi IGUCHI
  • Patent number: 8378418
    Abstract: A bidirectional Trench Lateral Power MOSFET (TLPM) can achieve a high breakdown voltage and a low on-resistance. A plurality of straight-shaped islands having circular portions at both ends are surrounded by a trench arrangement. The islands provide first n source regions and a second n source region is formed on the outside of the islands. With such a pattern, the breakdown voltage in the case where the first n source regions are at a high potential can be higher than the breakdown voltage in the case where the second n source region is at a high potential. Alternatively, in the case of not changing the breakdown voltage, the on-resistance can be reduced.
    Type: Grant
    Filed: August 26, 2010
    Date of Patent: February 19, 2013
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Mutsumi Kitamura, Akio Sugi, Naoto Fujishima, Shinichiro Matsunaga
  • Patent number: 8084812
    Abstract: A semiconductor device and a method of fabrication thereof includes a bidirectional device having a high breakdown voltage and a decreased ON voltage. An n-type extended drain region is formed in the bottom surface of each trench. A p-type offset region is formed in each split semiconductor region. First and second n-source regions are formed in the surface of the p-type offset region. This reduces the in-plane distance between the first and second n-source regions to thereby increase the density of cells. The breakdown voltage is maintained along the trenches. This increases the resistance to high voltages. Channels are formed in the sidewalls of the trenches by making the voltage across each gate electrode higher than the voltage across each of the first and second n-source electrodes. Thus, a bidirectional LMOSFET through which current flows in both directions is achieved. The LMOSFET has a high breakdown voltage and a decreased ON voltage.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: December 27, 2011
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Mutsumi Kitamura, Naoto Fujishima
  • Patent number: 7902596
    Abstract: A semiconductor device and a method of fabrication thereof includes a bidirectional device having a high breakdown voltage and a decreased ON voltage. An n-type extended drain region is formed in the bottom surface of each trench. A p-type offset region is formed in each split semiconductor region. First and second n-source regions are formed in the surface of the p-type offset region. This reduces the in-plane distance between the first and second n-source regions to thereby increase the density of cells. The breakdown voltage is maintained along the trenches. This increases the resistance to high voltages. Channels are formed in the sidewalls of the trenches by making the voltage across each gate electrode higher than the voltage across each of the first and second n-source electrodes. Thus, a bidirectional LMOSFET through which current flows in both directions is achieved. The LMOSFET has a high breakdown voltage and a decreased ON voltage.
    Type: Grant
    Filed: August 16, 2004
    Date of Patent: March 8, 2011
    Assignee: Fuji Electric Systems Co., Ltd.
    Inventors: Mutsumi Kitamura, Naoto Fujishima
  • Publication number: 20100330398
    Abstract: A bidirectional Trench Lateral Power MOSFET (TLPM) can achieve a high breakdown voltage and a low on-resistance. A plurality of straight-shaped islands having circular portions at both ends are surrounded by a trench arrangement. The islands provide first n source regions and a second n source region is formed on the outside of the islands. With such a pattern, the breakdown voltage in the case where the first n source regions are at a high potential can be higher than the breakdown voltage in the case where the second n source region is at a high potential. Alternatively, in the case of not changing the breakdown voltage, the on-resistance can be reduced.
    Type: Application
    Filed: August 26, 2010
    Publication date: December 30, 2010
    Applicant: Fuji Electric Systems Co., Ltd.
    Inventors: Mutsumi Kitamura, Akio Sugi, Naoto Fujishima, Shinichiro Matsunaga
  • Patent number: 7800167
    Abstract: A bidirectional Trench Lateral Power MOSFET (TLPM) can achieve a high breakdown voltage and a low on-resistance. A plurality of straight-shaped islands having circular portions at both ends are surrounded by a trench arrangement. The islands provide first n source regions and a second n source region is formed on the outside of the islands. With such a pattern, the breakdown voltage in the case where the first n source regions are at a high potential can be higher than the breakdown voltage in the case where the second n source region is at a high potential. Alternatively, in the case of not changing the breakdown voltage, the on-resistance can be reduced.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: September 21, 2010
    Assignee: Fuji Electric Systems Co., Ltd.
    Inventors: Mutsumi Kitamura, Akio Sugi, Naoto Fujishima, Shinichiro Matsunaga
  • Patent number: 7687385
    Abstract: The invention provides a semiconductor device exhibiting a stable and high breakdown voltage, which is manufactured at a low manufacturing cost. The semiconductor device of the invention includes an n-type silicon substrate; a p-type base region in the surface portion of substrate; an n-type drain region in the surface portion of n-type substrate; a p-type offset region in the surface portion of n-type substrate; an n-type source region in the surface portion of p-type base region; a p-type contact region in the surface portion of p-type base region; a gate electrode above the extended portion of p-type base region extending between n-type source region and n-type substrate (or p-type offset region), with a gate insulation film interposed therebetween; an insulation film on gate electrode and p-type offset region; a source electrode on n-type source region; and a drain electrode on n-type drain region.
    Type: Grant
    Filed: March 2, 2007
    Date of Patent: March 30, 2010
    Assignee: Fuji Electric Holdings Co., Ltd.
    Inventors: Kazuo Matsuzaki, Naoto Fujishima, Akio Kitamura, Gen Tada, Masaru Saito
  • Publication number: 20100044749
    Abstract: A semiconductor device and a method of fabrication thereof includes a bidirectional device having a high breakdown voltage and a decreased ON voltage. An n-type extended drain region is formed in the bottom surface of each trench. A p-type offset region is formed in each split semiconductor region. First and second n-source regions are formed in the surface of the p-type offset region. This reduces the in-plane distance between the first and second n-source regions to thereby increase the density of cells. The breakdown voltage is maintained along the trenches. This increases the resistance to high voltages. Channels are formed in the sidewalls of the trenches by making the voltage across each gate electrode higher than the voltage across each of the first and second n-source electrodes. Thus, a bidirectional LMOSFET through which current flows in both directions is achieved. The LMOSFET has a high breakdown voltage and a decreased ON voltage.
    Type: Application
    Filed: November 4, 2009
    Publication date: February 25, 2010
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventors: Mutsumi KITAMURA, Naoto FUJISHIMA
  • Patent number: 7476942
    Abstract: The SOI lateral semiconductor device includes a semiconductor region of a first conductivity type, a buried oxide film layer in the semiconductor region, a thin active layer on the buried oxide film layer, an anode region in the thin active layer, and a drain layer contacting the buried oxide film layer for confining the minority carriers injected from the anode region to the thin active layer within the thin active layer and for forming a structure that sustains a high breakdown voltage. The SOI lateral semiconductor device can provide a high breakdown voltage and low switching losses using the thin buried oxide film, which can be formed by an implanted oxygen (SIMOX) method.
    Type: Grant
    Filed: April 8, 2007
    Date of Patent: January 13, 2009
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventors: Yasumasa Watanabe, Hideaki Teranishi, Naoto Fujishima
  • Publication number: 20080303087
    Abstract: Gate electrodes of a TLPM and gate electrodes of planar devices are formed by patterning a same polysilicon layer. Drain electrode(s) and source electrode(s) of the TLPM and drain electrodes and source electrodes of the planar devices are formed by patterning a same metal layer. Therefore, the TLPM and the planar devices can be connected electrically to each other by resulting metal wiring layers and polysilicon layers without the need for performing wire bonding on a printed circuit board.
    Type: Application
    Filed: April 24, 2008
    Publication date: December 11, 2008
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akio Sugi, Naoto Fujishima, Mutsumi Kitamura, Katsuya Tabuchi, Setsuko Wakimoto
  • Patent number: 7445982
    Abstract: A method of manufacturing a semiconductor integrated circuit (IC) device that integrates a TLPM (trench lateral power MOSFET) and one or more planar semiconductor devices on a semiconductor substrate. In manufacturing the semiconductor IC device according to one embodiment, a trench etching forms a trench. A p-type body region, an n-type expanded drain region, and a thick oxide film are formed. A second trench etching deepens the trench. Gate oxide films and gate electrodes of the TLPM, an NMOSFET, and a PMOSFET are formed. P-type base regions of the TLPM and an NPN bipolar transistor are formed. An n-type source and drain region of the TLPM, and n-type diffusion regions of the NMOSFET and the NPN bipolar transistor are formed. P-type diffusion regions of the PMOSFET and the NPN bipolar transistor are formed. An interlayer oxide film, a contact electrode, and constituent metal electrodes are formed.
    Type: Grant
    Filed: August 28, 2007
    Date of Patent: November 4, 2008
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Naoto Fujishima, C. Andre T. Salama
  • Patent number: 7445983
    Abstract: A method of manufacturing a semiconductor integrated circuit (IC) device that integrates a TLPM (trench lateral power MOSFET) and one or more planar semiconductor devices on a semiconductor substrate. In manufacturing the semiconductor IC device according to one embodiment, a trench etching forms a trench. A p-type body region, an n-type expanded drain region, and a thick oxide film are formed. A second trench etching deepens the trench. Gate oxide films and gate electrodes of the TLPM, an NMOSFET, and a PMOSFET are formed. P-type base regions of the TLPM and an NPN bipolar transistor are formed. An n-type source and drain region of the TLPM, and n-type diffusion regions of the NMOSFET and the NPN bipolar transistor are formed. P-type diffusion regions of the PMOSFET and the NPN bipolar transistor are formed. An interlayer oxide film, a contact electrode, and constituent metal electrodes are formed.
    Type: Grant
    Filed: August 28, 2007
    Date of Patent: November 4, 2008
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Naoto Fujishima, C. Andre T. Salama
  • Publication number: 20080135927
    Abstract: An insulated gate semiconductor device, specifically, a trench lateral MOSFET having improved hot carrier resistance can be provided without increasing the number of processes and device pitch and without degrading device breakdown voltages and on-resistance characteristics RonA. A junction depth Xj of a p base region of a TLPM (trench lateral power MOSFET) is made smaller than the depth of a trench, and the trench is formed with a depth Dt of about 1.2 ?m such that the junction does not contact a curved corner part at the bottom of the trench.
    Type: Application
    Filed: November 21, 2007
    Publication date: June 12, 2008
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventors: Masaharu YAMAJI, Naoto FUJISHIMA, Mutsumi KITAMURA
  • Patent number: 7365392
    Abstract: Gate electrodes of a TLPM and gate electrodes of planar devices are formed by patterning a same polysilicon layer. Drain electrode(s) and source electrode(s) of the TLPM and drain electrodes and source electrodes of the planar devices are formed by patterning a same metal layer. Therefore, the TLPM and the planar devices can be connected electrically to each other by resulting metal wiring layers and polysilicon layers without the need for performing wire bonding on a printed circuit board.
    Type: Grant
    Filed: December 14, 2004
    Date of Patent: April 29, 2008
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Akio Sugi, Naoto Fujishima, Mutsumi Kitamura, Katsuya Tabuchi, Setsuko Wakimoto
  • Patent number: 7344935
    Abstract: A method of manufacturing a semiconductor integrated circuit (IC) device that integrates a TLPM (trench lateral power MOSFET) and one or more planar semiconductor devices on a semiconductor substrate. In manufacturing the semiconductor IC device according to one embodiment, a trench etching forms a trench. A p-type body region, an n-type expanded drain region, and a thick oxide film are formed. A second trench etching deepens the trench. Gate oxide films and gate electrodes of the TLPM, an NMOSFET, and a PMOSFET are formed. P-type base regions of the TLPM and an NPN bipolar transistor are formed. An n-type source and drain region of the TLPM, and n-type diffusion regions of the NMOSFET and the NPN bipolar transistor are formed. P-type diffusion regions of the PMOSFET and the NPN bipolar transistor are formed. An interlayer oxide film, a contact electrode, and constituent metal electrodes are formed.
    Type: Grant
    Filed: August 18, 2004
    Date of Patent: March 18, 2008
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Naoto Fujishima, C. Andre T. Salama
  • Publication number: 20070298563
    Abstract: A method of manufacturing a semiconductor integrated circuit (IC) device that integrates a TLPM (trench lateral power MOSFET) and one or more planar semiconductor devices on a semiconductor substrate. In manufacturing the semiconductor IC device according to one embodiment, a trench etching forms a trench. A p-type body region, an n-type expanded drain region, and a thick oxide film are formed. A second trench etching deepens the trench. Gate oxide films and gate electrodes of the TLPM, an NMOSFET, and a PMOSFET are formed. P-type base regions of the TLPM and an NPN bipolar transistor are formed. An n-type source and drain region of the TLPM, and n-type diffusion regions of the NMOSFET and the NPN bipolar transistor are formed. P-type diffusion regions of the PMOSFET and the NPN bipolar transistor are formed. An interlayer oxide film, a contact electrode, and constituent metal electrodes are formed.
    Type: Application
    Filed: August 28, 2007
    Publication date: December 27, 2007
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Naoto Fujishima, C. Andre Salama
  • Publication number: 20070298562
    Abstract: A method of manufacturing a semiconductor integrated circuit (IC) device that integrates a TLPM (trench lateral power MOSFET) and one or more planar semiconductor devices on a semiconductor substrate. In manufacturing the semiconductor IC device according to one embodiment, a trench etching forms a trench. A p-type body region, an n-type expanded drain region, and a thick oxide film are formed. A second trench etching deepens the trench. Gate oxide films and gate electrodes of the TLPM, an NMOSFET, and a PMOSFET are formed. P-type base regions of the TLPM and an NPN bipolar transistor are formed. An n-type source and drain region of the TLPM, and n-type diffusion regions of the NMOSFET and the NPN bipolar transistor are formed. P-type diffusion regions of the PMOSFET and the NPN bipolar transistor are formed. An interlayer oxide film, a contact electrode, and constituent metal electrodes are formed.
    Type: Application
    Filed: August 28, 2007
    Publication date: December 27, 2007
    Applicant: Fui Electric Co., Ltd.
    Inventors: Naoto Fujishima, C.Andre Salama
  • Publication number: 20070274110
    Abstract: A bidirectional Trench Lateral Power MOSFET (TLPM) can achieve a high breakdown voltage and a low on-resistance. A plurality of straight-shaped islands having circular portions at both ends are surrounded by a trench arrangement. The islands provide first n source regions and a second n source region is formed on the outside of the islands. With such a pattern, the breakdown voltage in the case where the first n source regions are at a high potential can be higher than the breakdown voltage in the case where the second n source region is at a high potential. Alternatively, in the case of not changing the breakdown voltage, the on-resistance can be reduced.
    Type: Application
    Filed: May 25, 2007
    Publication date: November 29, 2007
    Applicant: Fuji Electric Device Technology Co., Ltd
    Inventors: Mutsumi Kitamura, Akio Sugi, Naoto Fujishima, Shinichiro Matsunaga