Patents by Inventor Tohru Ozaki
Tohru Ozaki 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).
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Patent number: 6762065Abstract: A lower electrode is formed on an insulating film on a semiconductor substrate. A pair of ferroelectric films are formed on the lower electrode separately from each other. An upper electrode is formed on each of the pair of ferroelectric films. A portion of the lower electrode on which the ferroelectric film is formed is thicker than a portion thereof on which the ferroelectric film is not formed. Such a structure is obtained by sequentially depositing the lower electrode, the ferroelectric film, and the upper electrode on the insulating film, forming a mask on the upper-electrode, using this mask to etch the upper-electrode and the ferroelectric film to thereby pattern a pair of upper electrodes and a pair of ferroelectric electrodes, forming such a mask that continuously covers the pair of upper electrodes and the pair of ferroelectric films, and then etching the lower-electrode material film.Type: GrantFiled: May 30, 2003Date of Patent: July 13, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Hiroyuki Kanaya, Yasuyuki Taniguchi, Tohru Ozaki, Yoshinori Kumura
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Patent number: 6759251Abstract: A semiconductor device having ferroelectric memory cells has memory cell transistors each including first and second source/drain regions. Plug electrodes are formed in contact with the first and second source/drain regions, respectively. A ferroelectric capacitor is formed on the plug electrode connected to the first source/drain region. The ferroelectric capacitor includes a first lower electrode formed on the plug electrode, a ferroelectric film formed on the first lower electrode, and an upper electrode formed on the ferroelectric film. A second lower electrode is formed on the plug electrode connected to the second source/drain region. Wiring is formed to connect the upper electrode to the corresponding second lower electrode.Type: GrantFiled: December 17, 2002Date of Patent: July 6, 2004Assignee: Kabushiki Kaisha ToshibaInventor: Tohru Ozaki
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Publication number: 20030205738Abstract: A lower electrode is formed on an insulating film on a semiconductor substrate. A pair of ferroelectric films are formed on the lower electrode separately from each other. An upper electrode is formed on each of the pair of ferroelectric films. A portion of the lower electrode on which the ferroelectric film is formed is thicker than a portion thereof on which the ferroelectric film is not formed. Such a structure is obtained by sequentially depositing the lower electrode, the ferroelectric film, and the upper electrode on the insulating film, forming a mask on the upper-electrode, using this mask to etch the upper-electrode and the ferroelectric film to thereby pattern a pair of upper electrodes and a pair of ferroelectric electrodes, forming such a mask that continuously covers the pair of upper electrodes and the pair of ferroelectric films, and then etching the lower-electrode material film.Type: ApplicationFiled: May 30, 2003Publication date: November 6, 2003Inventors: Hiroyuki Kanaya, Yasuyuki Taniguchi, Tohru Ozaki, Yoshinori Kumura
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Patent number: 6635933Abstract: Capacitors are formed in the trenches made in an interlayer insulator made of silicon oxide. An insulating film (e.g., a silicon nitride film) is provided on the sides of each trench of the interlayer insulator. A storage electrode made of ruthenium or the like is provided in each trench of the interlayer insulator. A capacitor insulating film made of BSTO or the like is formed on the storage electrode. A plate electrode made of ruthenium or the like is formed on the capacitor insulating film. The plate electrode is common to all capacitors provided. Any two adjacent capacitors are electrically isolated by the interlayer insulator and the insulating film provided on the sides of the trenches of the interlayer insulator.Type: GrantFiled: September 17, 2001Date of Patent: October 21, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Yutaka Ishibashi, Yusuke Kohyama, Tohru Ozaki
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Patent number: 6611015Abstract: A semiconductor memory device including a memory cell block having a plurality of memory transistors formed on a semiconductor substrate. The memory transistors include first and second impurity-diffused regions and a gate formed therebetween. A plurality of memory cells are also included in the memory cell block and have lower electrodes connected to the first impurity-diffused regions, ferroelectric films formed on the lower electrodes and first upper electrodes formed on the ferroelectric films and connected to the second impurity-diffused regions. Further included are block selecting transistors formed on the semiconductor substrate and being connected to one end of the memory cell block. Second upper electrodes are also formed adjoined to the block selecting transistors and being disconnected from the first upper electrode of the memory cells.Type: GrantFiled: September 20, 2001Date of Patent: August 26, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Tohru Ozaki, Iwao Kunishima, Toyota Morimoto, Hiroyuki Kanaya
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Patent number: 6603161Abstract: There is provided a semiconductor device having a ferroelectric capacitor formed on a semiconductor substrate covered with an insulator film, wherein the ferroelectric capacitor comprises: a bottom electrode formed on the insulator film; a ferroelectric film formed on the bottom electrode; and a top electrode formed on the ferroelectric film. The ferroelectric film has a stacked structure of either of two-layer-ferroelectric film or three-layer-ferroelectric film. The upper ferroelectric film is metallized and prevents hydrogen from diffusing in lower ferroelectric layer. Crystal grains of the stacked ferroelectric films are preferably different.Type: GrantFiled: March 9, 2001Date of Patent: August 5, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Hiroyuki Kanaya, Yasuyuki Taniguchi, Tohru Ozaki, Yoshinori Kumura
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Publication number: 20030094639Abstract: A semiconductor device having ferroelectric memory cells has memory cell transistors each including first and second source/drain regions. Plug electrodes are formed in contact with the first and second source/drain regions, respectively. A ferroelectric capacitor is formed on the plug electrode connected to the first source/drain region. The ferroelectric capacitor includes a first lower electrode formed on the plug electrode, a ferroelectric film formed on the first lower electrode, and an upper electrode formed on the ferroelectric film. A second lower electrode is formed on the plug electrode connected to the second source/drain region. Wiring is formed to connect the upper electrode to the corresponding second lower electrode.Type: ApplicationFiled: December 17, 2002Publication date: May 22, 2003Applicant: Kabushiki Kaisha ToshibaInventor: Tohru Ozaki
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Patent number: 6521929Abstract: A semiconductor device having ferroelectric memory cells has memory cell transistors each including first and second source/drain regions. Plug electrodes are formed in contact with the first and second source/drain regions, respectively. A ferroelectric capacitor is formed on the plug electrode connected to the first source/drain region. The ferroelectric capacitor includes a first lower electrode formed on the plug electrode, a ferroelectric film formed on the first lower electrode, and an upper electrode formed on the ferroelectric film. A second lower electrode is formed on the plug electrode connected to the second source/drain region. Wiring is formed to connect the upper electrode to the corresponding second lower electrode.Type: GrantFiled: March 26, 2001Date of Patent: February 18, 2003Assignee: Kabushiki Kaisha ToshibaInventor: Tohru Ozaki
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Patent number: 6448618Abstract: In a DRAM, a plurality of first MOSFETs are formed in a cell region on a semiconductor substrate based on the minimum design rule, and a first gate side-wall having a side-wall insulation film is formed on the side-wall portion of a first gate electrode of each of the first MOSFETs. At least one second MOSFET is formed in a peripheral circuit region on the semiconductor substrate, and a second gate side-wall having side-wall insulation films is formed on the side-wall portion of a second gate electrode of the second MOSFET. Both the first MOSFETs, which is capable of forming a fine contact hole self-aligned with the first gate electrode, and the second MOSFET, which is capable of sufficiently mitigating the parasitic resistance while suppressing the short channel effect, can be formed on the same substrate.Type: GrantFiled: August 18, 2000Date of Patent: September 10, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Satoshi Inaba, Tohru Ozaki, Yusuke Kohyama, Kazumesa Sunouchi
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Publication number: 20020096771Abstract: A highly reliable and highly characteristic semiconductor memory device capable of being subjected to a heat treatment process at a necessary temperature after forming a ferroelectric capacitor and wiring is provided. In Series connected TC unit ferroelectric RAM, a first contact portion of one of source/drain diffusion layers and a lower electrode and a second contact portion of an upper electrode and the other of the source/drain diffusion layers and are formed of a first oxidation resistant conductive film and a second oxidation resistant conductive film, respectively. By utilizing a memory cell block structure proper to the Series connected TC unit ferroelectric RAM, on a capacitor, provided is a hydrogen blocking film having an opening defined in a region without a memory cell, the region being present for each memory cell block.Type: ApplicationFiled: December 12, 2001Publication date: July 25, 2002Applicant: Kabushiki Kaisha ToshibaInventors: Yuki Yamada, Masami Aoki, Tohru Ozaki
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Publication number: 20020033494Abstract: A semiconductor memory device including a memory cell block having a plurality of memory transistors formed on a semiconductor substrate. The memory transistors include first and second impurity-diffused regions and a gate formed therebetween. A plurality of memory cells are also included in the memory cell block and have lower electrodes connected to the first impurity-diffused regions, ferroelectric films formed on the lower electrodes and first upper electrodes formed on the ferroelectric films and connected to the second impurity-diffused regions. Further included are block selecting transistors formed on the semiconductor substrate and being connected to one end of memory cell block. Second upper electrodes are also formed adjoined to the block selecting transistors and being disconnected from the first upper electrode of the memory cells.Type: ApplicationFiled: September 20, 2001Publication date: March 21, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tohru Ozaki, Iwao Kunishima, Toyota Morimoto, Hiroyuki Kanaya
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Publication number: 20020011618Abstract: Capacitors are formed in the trenches made in an interlayer insulator made of silicon oxide. An insulating film (e.g., a silicon nitride film) is provided on the sides of each trench of the interlayer insulator. A storage electrode made of ruthenium or the like is provided in each trench of the interlayer insulator. A capacitor insulating film made of BSTO or the like is formed on the storage electrode. A plate electrode made of ruthenium or the like is formed on the capacitor insulating film. The plate electrode is common to all capacitors provided. Any two adjacent capacitors are electrically isolated by the interlayer insulator and the insulating film provided on the sides of the trenches of the interlayer insulator.Type: ApplicationFiled: September 17, 2001Publication date: January 31, 2002Applicant: Kabushiki Kaisha ToshibaInventors: Yutaka Ishibashi, Yusuke Kohyama, Tohru Ozaki
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Publication number: 20020000585Abstract: A semiconductor device having ferroelectric memory cells has memory cell transistors each including first and second source/drain regions. Plug electrodes are formed in contact with the first and second source/drain regions, respectively. A ferroelectric capacitor is formed on the plug electrode connected to the first source/drain region. The ferroelectric capacitor includes a first lower electrode formed on the plug electrode, a ferroelectric film formed on the first lower electrode, and an upper electrode formed on the ferroelectric film. A second lower electrode is formed on the plug electrode connected to the second source/drain region. Wiring is formed to connect the upper electrode to the corresponding second lower electrode.Type: ApplicationFiled: March 26, 2001Publication date: January 3, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Tohru Ozaki
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Patent number: 6303429Abstract: Capacitors are formed in the trenches made in an interlayer insulator made of silicon oxide. An insulating film (e.g., a silicon nitride film) is provided on the sides of each trench of the interlayer insulator. A storage electrode made of ruthenium or the like is provided in each trench of the interlayer insulator. A capacitor insulating film made of BSTO or the like is formed on the storage electrode. A plate electrode made of ruthenium or the like is formed on the capacitor insulating film. The plate electrode is common to all capacitors provided. Any two adjacent capacitors are electrically isolated by the interlayer insulator and the insulating film provided on the sides of the trenches of the interlayer insulator.Type: GrantFiled: October 2, 2000Date of Patent: October 16, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Yutaka Ishibashi, Yusuke Kohyama, Tohru Ozaki
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Publication number: 20010022372Abstract: There is provided a semiconductor device having a ferroelectric capacitor formed on a semiconductor substrate covered with an insulator film, wherein the ferroelectric capacitor comprises: a bottom electrode formed on the insulator film; a ferroelectric film formed on the bottom electrode; and a top electrode formed on the ferroelectric film. The ferroelectric film has a stacked structure of either of two-layer-ferroelectric film or three-layer-ferroelectric film. The upper ferroelectric film is metallized and prevents hydrogen from diffusing in lower ferroelectric layer. Crystal grains of the stacked ferroelectric films are preferably different.Type: ApplicationFiled: March 9, 2001Publication date: September 20, 2001Inventors: Hiroyuki Kanaya, Yasuyuki Taniguchi, Tohru Ozaki, Yoshinori Kumura
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Patent number: 6180973Abstract: A semiconductor memory device includes a semiconductor substrate, an element isolation film formed on the substrate, element formation regions each defined in an island form in the surface of the substrate by the element isolation film, trenches formed in the element formation regions, respectively, capacitors each formed in a corresponding one of the trenches, each having a plate electrode formed of the substrate, a capacitor insulating film formed on the inner wall of the trench and a storage electrode filled in the trench with the capacitor insulating film disposed therebetween, transistors each formed in the element formation regions, and having a gate electrode which is formed to extend over the substrate and pass over the trench and the element formation region, a first impurity diffusion layer formed on one side of the gate electrode, a second impurity diffusion layer formed on the other side of the gate electrode, and channel regions formed on the element formation region on both sides of the trench bType: GrantFiled: April 30, 1998Date of Patent: January 30, 2001Assignee: Kabushiki Kaisha ToshibaInventor: Tohru Ozaki
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Patent number: 6162720Abstract: A method of manufacturing a semiconductor device. First, a plurality of wires are arranged in parallel to one another, on a semiconductor substrate. Then, insulating films of a first group are formed on tops of the wires, respectively. Next, second insulating films of a second group are formed on sides of the wires, respectively. Further, among the wires there are formed insulating films of a third group which have upper surfaces located at a level not higher than upper surfaces of the insulating films of the second group. Thereafter, contact holes are formed by subjecting the insulating films of the third group to selectively etching. Finally, the contact holes are filled with electrically conductive material.Type: GrantFiled: December 22, 1998Date of Patent: December 19, 2000Assignee: Kabushiki Kaisha ToshibaInventor: Tohru Ozaki
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Patent number: 6153476Abstract: In a DRAM, a plurality of first MOSFETs are formed in a cell region on a semiconductor substrate based on the minimum design rule, and a first gate side-wall having a side-wall insulation film is formed on the side-wall portion of a first gate electrode of each of the first MOSFETs. At least one second MOSFET is formed in a peripheral circuit region on the semiconductor substrate, and a second gate side-wall having side-wall insulation films is formed on the side-wall portion of a second gate electrode of the second MOSFET. Both the first MOSFETs, which is capable of forming a fine contact hole self-aligned with the first gate electrode, and the second MOSFET, which is capable of sufficiently mitigating the parasitic resistance while suppressing the short channel effect, can be formed on the same substrate.Type: GrantFiled: February 25, 1998Date of Patent: November 28, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Satoshi Inaba, Tohru Ozaki, Yusuke Kohyama, Kazumasa Sunouchi
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Patent number: 6104052Abstract: In a DRAM adopting a self-aligned contact structure, an opening portion of predetermined size is formed in advance in an insulation film which surrounds an on-field gate electrode formed on an element isolating insulation film. The on-field gate electrode contacts a gate contact through the opening portion. A contact hole for the gate contact can thus be formed in self-alignment as can be the contact holes for a bit-line contact and an active contact. Consequently, the contact hole for the gate contact reaching the on-field gate can be formed simultaneously with the contact holes for the bit-line contact and active contact, thereby greatly reducing the number of manufacturing steps.Type: GrantFiled: March 22, 1999Date of Patent: August 15, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Tohru Ozaki, Yusuke Kohyama
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Patent number: 6078073Abstract: A gate electrode having a first insulating film laminated in the upper portion thereof is formed on a gate insulating film formed on a semiconductor substrate. A side wall is formed on the side wall of the gate electrode, and an insulating film is formed to cover the gate electrode and the side wall. Ion implantation is performed through the insulating film so that a diffusion layer is formed on the semiconductor substrate. An interlayer dielectric film is formed, and then the interlayer dielectric film and the insulating film are selectively etched so that an opening portion for exposing the gate insulating film is formed in a self-align manner with the gate electrode. Then, the gate insulating film in the bottom portion of the opening portion is removed so that the surface of the semiconductor substrate is exposed. Then, a wiring layer connected to the exposed surface of the semiconductor substrate is formed.Type: GrantFiled: June 18, 1997Date of Patent: June 20, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Mariko Habu, Kazumasa Sunouchi, Masami Aoki, Tohru Ozaki