Patents by Inventor Toshiaki Nishimoto

Toshiaki Nishimoto 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: 20020173091
    Abstract: In the semiconductor integrated circuit device, an AND-type flash memory is formed on a substrate in which stripe-like element separation regions 5 are formed and active regions L sandwiched between the element separation regions 5 are formed like stripes. A silicon monocrystal substrate containing nitrogen or carbon is used as the semiconductor substrate, to reduce dislocation defects and junction leakages so that the reliability and yield are improved.
    Type: Application
    Filed: June 26, 2002
    Publication date: November 21, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Toshiaki Nishimoto, Takashi Aoyagi, Shogo Kiyota
  • Patent number: 6451643
    Abstract: A method of manufacturing a semiconductor memory device having nonvolatile memory cells each formed of a MISFET having both a floating gate and a control gate and first and second semiconductor regions. By this method, an impurity, for example, arsenic, is introduced to form both the first and second semiconductor regions but, however, a lower dose of arsenic is introduced in the formation of the second semiconductor region. The first semiconductor region is formed to have a junction depth greater than that of the second semiconductor region, and both the first and second semiconductor regions have portions thereof extending under the floating gate electrode. Carriers stored in the floating gate electrode are transferred between the floating gate electrode and the first semiconductor region by tunneling through the insulating film beneath the floating gate electrode. The method further features the formation of MISFETs of peripheral circuits.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: September 17, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 6444514
    Abstract: In the semiconductor integrated circuit device, an AND-type flash memory is formed on a substrate in which stripe-like element separation regions 5 are formed and active regions L sandwiched between the element separation regions 5 are formed like stripes. A silicon monocrystal substrate containing nitrogen or carbon is used as the semiconductor substrate, to reduce dislocation defects and junction leakages so that the reliability and yield are improved.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: September 3, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Nishimoto, Takashi Aoyagi, Shogo Kiyota
  • Patent number: 6442070
    Abstract: A nonvolatile semiconductor memory device is provided which includes a plurality of memory cells each having a floating gate, wherein a threshold level of each memory cell depends on a value of electric charge in said floating gate of said memory cell, and wherein said threshold level of each memory cell is placed at one of a first area and a second area. A controller is also provided which controls to set each threshold voltage of selected ones of said plurality of memory cells, wherein said controller performs a first setting operation and a verifying operation. The first setting operation shifts threshold voltages of the selected ones of said plurality of memory cells in a direction from said first area to said second area. The verifying operation detects erratic memory cells which have threshold voltages which are on a side of said second area which is opposite of a middle area formed between the first area and the second area.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: August 27, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Toshihiro Tanaka, Masataka Kato, Osamu Tsuchiya, Toshiaki Nishimoto
  • Publication number: 20020064921
    Abstract: In a flash memory having enhanced reliability, each memory cell has a floating gate electrode which is formed on a semiconductor substrate by being interposed by a gate insulation film, a control gate electrode which is formed on the floating gate electrode by being interposed by an inter-layer film, a pair of n-type semiconductor regions (source regions) formed on the semiconductor substrate to confront two sidewise portions of the floating gate electrode, an n-type semiconductor region (drain region) formed beneath the n-type semiconductor region pair by being interposed by channel well regions, and a common p-well formed beneath the semiconductor region. The n-type semiconductor regions and channel well regions make up the DD structure.
    Type: Application
    Filed: October 2, 2001
    Publication date: May 30, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Masataka Kato, Toshiaki Nishimoto
  • Publication number: 20010038119
    Abstract: A method of manufacturing a semiconductor memory device having nonvolatile memory cells each formed of a MISFET having both a floating gate and a control gate and first and second semiconductor regions. By this method, an impurity, for example, arsenic, is introduced to form both the first and second semiconductor regions but, however, a lower dose of arsenic is introduced in the formation of the second semiconductor region. The first semiconductor region is formed to have a junction depth greater than that of the second semiconductor region, and both the first and second semiconductor regions have portions thereof extending under the floating gate electrode. Carriers stored in the floating gate electrode are transferred between the floating gate electrode and the first semiconductor region by tunneling through the insulating film beneath the floating gate electrode. The method further features the formation of MISFETs of peripheral circuits.
    Type: Application
    Filed: June 5, 2001
    Publication date: November 8, 2001
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 6255690
    Abstract: A semiconductor memory device having nonvolatile memory cells of a single-element type. The nonvolatile memory cells have a floating gate electrode insulatedly on a main surface of a semiconductor substrate and a control gate electrode on the floating gate via a second gate insulating film. An impurity, for example, arsenic, is introduced in self-alignment with the pair of opposing end sides of the control gate electrode to form both the first and second semiconductor regions but, however, a lower dose of arsenic is introduced in the formation of the second semiconductor region. In accordance with the scheme, the first semiconductor region is formed to have a junction depth greater than the junction depth associated with the second semiconductor region and both the first and second semiconductor regions have portions thereof extending under the floating gate electrode.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: July 3, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 6130841
    Abstract: After decreasing the threshold voltages of a plurality of memory cells collectively or selectively, the presence or absence of any memory cell of which the threshold voltage has dropped below a predetermined voltage verified collectively for each of memory cell groups connected to word line (low-threshold value verification) , and any memory cell of which the threshold voltage has excessively dropped is selectively written. Also, the well of each of memory cell is formed in the region of an element isolation layer for isolating it from the substrate of a memory apparatus, and a negative voltage is supplied to the memory well distributively with a positive voltage applied as a word line voltage, thus supplying them as erase operation voltages. The absolute value of the memory well voltage is set substantially equal to or lower than the word line voltage for the read operation.
    Type: Grant
    Filed: November 2, 1999
    Date of Patent: October 10, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Toshihiro Tanaka, Masataka Kato, Osamu Tsuchiya, Toshiaki Nishimoto
  • Patent number: 5978270
    Abstract: After decreasing the threshold voltages of a plurality of memory cells collectively or selectively, the presence or absence of any memory cell of which the threshold voltage has dropped below a predetermined voltage verified collectively for each of memory cell groups connected to word line (low-threshold value verification), and any memory cell of which the threshold voltage has excessively dropped is selectively written. Also, the well of each of memory cell is formed in the region of an element isolation layer for isolating it from the substrate of a memory apparatus, and a negative voltage is supplied to the memory well distributively with a positive voltage applied as a word line voltage, thus supplying them as erase operation voltages. The absolute value of the memory well voltage is set substantially equal to or lower than the word line voltage for the read operation.
    Type: Grant
    Filed: March 2, 1998
    Date of Patent: November 2, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Toshihiro Tanaka, Masataka Kato, Osamu Tsuchiya, Toshiaki Nishimoto
  • Patent number: 5904518
    Abstract: A method of manufacturing a semiconductor memory device having nonvolatile memory cells of a single-element type. The method provides for the formation of a floating gate electrode insulatedly on a main surface of a semiconductor substrate and a control gate electrode on the floating gate via a second gate insulating film. Also by this method, an impurity, for example, arsenic, is introduced in self-alignment with the pair of opposing end sides of the control gate electrode to form both the first and second semiconductor regions but, however, a lower dose of arsenic is introduced in the formation of the second semiconductor region. In accordance with the scheme, the first semiconductor region is formed to have a junction depth greater than the junction depth associated with the second semiconductor region and both the first and second semiconductor regions have portions thereof extending under the floating gate electrode.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: May 18, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5814543
    Abstract: A method for fabricating a semiconductor integrated circuit device comprising a nonvolatile memory cell, comprises the steps of forming a first gate material which comprises a silicon film containing no impurities, whose top surface is covered with an oxidation-resistant mask, and whose width in the gate-length direction is prescribed, on part of the surface of a first gate insulating film, forming a thermal-oxidation insulating film on the surface of an active region of a semiconductor substrate through thermal oxidation, removing an oxidation-resistant mask, forming a second gate material which comprises a silicon film into which impurities are introduced and whose width in the gate-length direction is prescribed, on each surface of the thermal-oxidation insulating film and the first gate material forming a second gate insulating film on the surface of the second gate material, and forming a third gate material on the surface of the second gate insulating film.
    Type: Grant
    Filed: November 22, 1995
    Date of Patent: September 29, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Nishimoto, Shoji Shukuri, Tsutomu Okazaki, Hideo Tobe, Kazuhiro Komori, Masataka Kato, Hitoshi Kume
  • Patent number: 5656522
    Abstract: A method of manufacturing a semiconductor memory device having non-volatile memory elements or memory cells of a single-element type. The method provides for the formation of a floating gate electrode on a main surface of a semiconductor substrate and a control gate electrode on the floating gate electrode via a second gate insulating film. In accordance with the method, an impurity is introduced in self-alignment with one of a pair of opposing end portions of the control gate electrode to form a first semiconductor region, and on the second of the opposing end portions of the control gate electrode of the memory cell, the same impurity, for example, arsenic, but, however, of a lower dose is introduced in self-alignment to form a second semiconductor region.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: August 12, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5656839
    Abstract: A semiconductor integrated device having a non-volatile memory element or memory cell of a single-element type in a non-volatile memory circuit employing a field effect transistor which has, in addition to a floating gate electrode for storage of information and a controlling gate electrode, a source which includes a heavily doped region having a depth into the semiconductor substrate extending from the major surface thereof which is large. The single-element type field effect transistor, furthermore, has a drain which includes a lightly doped region which has a depth extending into the semiconductor substrate from the major surface thereof which is small.
    Type: Grant
    Filed: April 17, 1995
    Date of Patent: August 12, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5629541
    Abstract: A semiconductor integrated device having a non-volatile memory element or memory cell of a single-element type in a non-volatile memory circuit employing a field effect transistor which has, in addition to a floating gate electrode for storage of information and a controlling gate electrode, a source which includes a heavily doped region having a depth into the semiconductor substrate extending from the major surface thereof which is large. The single-element type field effect transistor, furthermore, has a drain which includes a lightly doped region which has a depth extending into the semiconductor substrate from the major surface thereof which is small.
    Type: Grant
    Filed: April 17, 1995
    Date of Patent: May 13, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5602048
    Abstract: An EEPROM (Electrically Erasable Programmable Read Only Memory) has a structure in which the corners of a floating gate electrode of each memory cell MISFET near the source region thereof are rounded.The EEPROM is manufactured by a method characterized in that the ions of an impurity at a high dose are implanted in self-alignment with the floating gate electrode and control gate electrode of the memory cell MISFET so as to form the source and drain regions thereof, whereupon an oxidizing treatment is carried out.
    Type: Grant
    Filed: May 17, 1995
    Date of Patent: February 11, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Satoshi Meguro, Toshiaki Nishimoto, Hitoshi Kume, Hideaki Yamamoto
  • Patent number: 5445980
    Abstract: An EEPROM (Electrically Erasable Programmable Read Only Memory) has a structure in which the corners of a floating gate electrode of each memory cell MISFET near the source region thereof are rounded.The EEPROM is manufactured by a method characterized in that the ions of an impurity at a high dose are implanted in self-alignment with the floating gate electrode and control gate electrode of the memory cell MISFET so as to form the source and drain regions thereof, whereupon an oxidizing treatment is carried out.
    Type: Grant
    Filed: November 4, 1993
    Date of Patent: August 29, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Satoshi Meguro, Toshiaki Nishimoto, Hitoshi Kume, Hideaki Yamamoto
  • Patent number: 5427966
    Abstract: Herein disclosed is a semiconductor integrated circuit device having a nonvolatile memory function and including a memory cell composed of a field effect transistor having a floating gate electrode and a control gate electrode. A first insulating film for element isolation is buried between the floating gate electrodes. The size of the drain region of the field effect transistor is substantially regulated by both the gap between the first insulating films adjacent to the drain region and the gap between the control gate electrodes adjacent to the drain region. The gaps between the data line at the connection portion with the drain region and the first insulating films individually adjacent to the drain region are equalized. The gaps between the data line at the connection portion with the drain region and the floating gate electrodes or control gate electrodes individually adjacent to the drain region are equalized.
    Type: Grant
    Filed: August 3, 1993
    Date of Patent: June 27, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto
  • Patent number: 5407853
    Abstract: A semiconductor integrated device having a non-volatile memory element or memory cell of a single-element type in a non-volatile memory circuit employing a field effect transistor which has, in addition to a floating gate electrode for storage of information and a controlling gate electrode, a source which includes a heavily doped region having a depth into the semiconductor substrate extending from the major surface thereof which is large. The single-element type field effect transistor, furthermore, has a drain which includes a lightly doped region which has a depth extending into the semiconductor substrate from the major surface thereof which is small.
    Type: Grant
    Filed: January 11, 1994
    Date of Patent: April 18, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5300802
    Abstract: A semiconductor integrated device having a non-volatile memory element or memory cell of a single-element type in a non-volatile memory circuit employing a field effect transistor which has, in addition to a floating gate electrode for storage of information and a controlling gate electrode, a source which includes a heavily doped region having a depth into the semiconductor substrate extending from the major surface thereof which is large. The single-element type field effect transistor, furthermore, has a drain which includes a lightly doped region which has a depth extending into the semiconductor substrate from the major surface thereof which is small.
    Type: Grant
    Filed: May 20, 1991
    Date of Patent: April 5, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto, Satoshi Meguro, Hitoshi Kume, Yoshiaki Kamigaki
  • Patent number: 5235200
    Abstract: Herein disclosed is a semiconductor integrated circuit device having a nonvolatile memory function and including a memory cell composed of a field effect transistor having a floating gate electrode and a control gate electrode. A first insulating film for element isolation is buried between the floating gate electrodes. The size of the drain region of the field effect transistor is substantially regulated by both the gap between the first insulating films adjacent to the drain region and the gap between the control gate electrodes adjacent to the drain region. The gaps between the data line at the connection portion with the drain region and the first insulating films individually adjacent to the drain region are equalized. The gaps between the data line at the connection portion with the drain region and the floating gate electrodes or control gate electrodes individually adjacent to the drain region are equalized.
    Type: Grant
    Filed: November 1, 1990
    Date of Patent: August 10, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Komori, Toshiaki Nishimoto