Patents by Inventor Akito Hara
Akito Hara 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: 6660085Abstract: A polycrystal thin film forming method comprising the step of forming a semiconductor thin film on a substrate 14, and the step of flowing a heated gas to the semiconductor thin film while an energy beam 38 is being applied to the semiconductor thin film at a region to which the gas is being applied to thereby melt the semiconductor film, and crystallizing the semiconductor thin film in its solidification. The energy beam is applied while the high-temperature gas is being flowed, whereby the melted semiconductor thin film can have low solidification rate, whereby the polycrystal thin film can have large crystal grain diameters and can have good quality of little defects in crystal grains and little twins.Type: GrantFiled: March 21, 2001Date of Patent: December 9, 2003Assignee: Fujitsu LimitedInventors: Akito Hara, Kuninori Kitahara
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Publication number: 20030190777Abstract: A polycrystal thin film forming method comprising the step of forming a semiconductor thin film on a substrate 14, and the step of flowing a heated gas to the semiconductor thin film while an energy beam 38 is being applied to the semiconductor thin film at a region to which the gas is being applied to thereby melt the semiconductor film, and crystallizing the semiconductor thin film in its solidification. The energy beam is applied while the high-temperature gas is being flowed, whereby the melted semiconductor thin film can have low solidification rate, whereby the polycrystal thin film can have large crystal grain diameters and can have good quality of little defects in crystal grains and little twins.Type: ApplicationFiled: April 22, 2003Publication date: October 9, 2003Applicant: FUJITSU LIMITEDInventors: Akito Hara, Nobuo Sasaki
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Patent number: 6582996Abstract: A polycrystal thin film forming method comprising the step of forming a semiconductor thin film on a substrate 14, and the step of flowing a heated gas to the semiconductor thin film while an energy beam 38 is being applied to the semiconductor thin film at a region to which the gas is being applied to thereby melt the semiconductor film, and crystallizing the semiconductor thin film in its solidification. The energy beam is applied while the high-temperature gas is being flowed, whereby the melted semiconductor thin film can have low solidification rate, whereby the polycrystal thin film can have large crystal grain diameters and can have good quality of little defects in crystal grains and little twins.Type: GrantFiled: August 30, 2000Date of Patent: June 24, 2003Assignee: Fujitsu LimitedInventors: Akito Hara, Nobuo Sasaki
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Publication number: 20030104682Abstract: An a-Si film is patterned into a linear shape (ribbon shape) or island shape on a glass substrate. The upper surface of the a-Si film or the lower surface of the glass substrate is irradiated and scanned with an energy beam output continuously along the time axis from a CW laser in a direction indicated by an arrow, thereby crystallizing the a-Si film. This implements a TFT in which the transistor characteristics of the TFT are made uniform at high level, and the mobility is high particularly in a peripheral circuit region to enable high-speed driving in applications to a system-on glass and the like.Type: ApplicationFiled: November 13, 2002Publication date: June 5, 2003Applicant: Fujitsu LimitedInventors: Akito Hara, Fumiyo Takeuchi, Kenichi Yoshino, Nobuo Sasaki
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Publication number: 20030094585Abstract: An a-Si film is patterned into a linear shape (ribbon shape) or island shape on a glass substrate. The upper surface of the a-Si film or the lower surface of the glass substrate is irradiated and scanned with an energy beam output continuously along the time axis from a CW laser in a direction indicated by an arrow, thereby crystallizing the a-Si film. This implements a TFT in which the transistor characteristics of the TFT are made uniform at high level, and the mobility is high particularly in a peripheral circuit region to enable high-speed driving in applications to a system-on glass and the like.Type: ApplicationFiled: November 13, 2002Publication date: May 22, 2003Applicant: Fujitsu Limited,Inventors: Akito Hara, Fumiyo Takeuchi, Kenichi Yoshino, Nobuo Sasaki
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Patent number: 6566754Abstract: A method of manufacturing a semiconductor device having a polycrystalline semiconductor layer includes the steps of: preparing a base substrate; forming a first semiconductor layer on a surface of the base substrate; forming a first polycrystalline semiconductor layer by applying an energy beam to the first semiconductor layer; etching a surface layer of the first polycrystalline semiconductor layer; and after the etching process, forming a second semiconductor layer on a surface of the first polycrystalline semiconductor layer without exposing the surface of the first polycrystalline semiconductor layer to an atmospheric air. The final polycrystalline semiconductor layer has a high film quality.Type: GrantFiled: July 20, 2001Date of Patent: May 20, 2003Assignee: Fujitsu LimitedInventors: Akito Hara, Kuninori Kitahara, Satoshi Murakami
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Publication number: 20030042486Abstract: An operating semiconductor layer is formed in such a manner that amorphous silicon layer is formed to be shaped so that it has a wide region and a narrow region and the narrow region is connected to the wide region at a position asymmetric to the wide region, and the amorphous silicon layer is crystallized by scanning a CW laser beam from the wide region toward the narrow region in a state that a polycrystalline silicon layer as a heat-retaining layer encloses the narrow region from a side face through the silicon oxide layer.Type: ApplicationFiled: August 29, 2002Publication date: March 6, 2003Applicant: FUJITSU LIMITEDInventors: Yasuyuki Sano, Akito Hara, Michiko Takei, Nobuo Sasaki
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Publication number: 20030017659Abstract: There is provided the step of forming a polysilicon film by scanning a laser irradiation region while irradiating a continuous wave laser onto an amorphous silicon film formed into an island or ribbon-like shape on a substrate. If a width of a rectangle in which the amorphous silicon film is inscribed is 30 &mgr;m or less, any one condition of (1) a top end shape of a pattern is a convex shape, (2) a top end shape is a concave shape and consists of straight lines and has three corner portions at a top end side, and both angles of the corner portions on both sides of the top end shape are set to 45 degree or more, (3) a top end shape is a concave shape and consists of curved lines, and (4) a width of a top end portion is 25 &mgr;m or less, is satisfied.Type: ApplicationFiled: January 3, 2002Publication date: January 23, 2003Applicant: FUJITSU LIMITEDInventors: Michiko Takei, Akito Hara
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Publication number: 20020031876Abstract: An a-Si film is patterned into a linear shape (ribbon shape) or island shape on a glass substrate. The upper surface of the a-Si film or the lower surface of the glass substrate is irradiated and scanned with an energy beam output continuously along the time axis from a CW laser in a direction indicated by an arrow, thereby crystallizing the a-Si film. This implements a TFT in which the transistor characteristics of the TFT are made uniform at high level, and the mobility is high particularly in a peripheral circuit region to enable high-speed driving in applications to a system-on glass and the like.Type: ApplicationFiled: August 22, 2001Publication date: March 14, 2002Applicant: FUJITSU LIMITEDInventors: Akito Hara, Fumiyo Takeuchi, Kenichi Yoshino, Nobuo Sasaki
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Patent number: 6335266Abstract: A polycrystalline semiconductor material containing Si, Ge or SiGe, wherein the material contains H atoms and the number of monohydride structures of couplings between Si or Ge, and H is larger than the number of higher-order hydride structures, or in other words, a peak intensity of a monohydride structure in a local vibration mode measured by a Raman spectral analysis is higher than a peak intensity of a higher-order hydride structure. By configuring the compositions of a polycrystalline semiconductor material in the above manner, the carrier mobility can be made high.Type: GrantFiled: May 15, 2000Date of Patent: January 1, 2002Assignee: Fujitsu LimitedInventors: Kuninori Kitahara, Satoshi Murakami, Akito Hara
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Publication number: 20010046755Abstract: A method of manufacturing a semiconductor device having a polycrystalline semiconductor layer includes the steps of: preparing a base substrate; forming a first semiconductor layer on a surface of the base substrate; forming a first polycrystalline semiconductor layer by applying an energy beam to the first semiconductor layer; etching a surface layer of the first polycrystalline semiconductor layer; and after the etching process, forming a second semiconductor layer on a surface of the first polycrystalline semiconductor layer without exposing the surface of the first polycrystalline semiconductor layer to an atmospheric air. The final polycrystalline semiconductor layer has a high film quality.Type: ApplicationFiled: July 20, 2001Publication date: November 29, 2001Applicant: FUJITSU LIMITEDInventors: Akito Hara, Kuninori Kitahara, Satoshi Murakami
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Publication number: 20010041391Abstract: A polycrystal thin film forming method comprising the step of forming a semiconductor thin film on a substrate 14, and the step of flowing a heated gas to the semiconductor thin film while an energy beam 38 is being applied to the semiconductor thin film at a region to which the gas is being applied to thereby melt the semiconductor film, and crystallizing the semiconductor thin film in its solidification. The energy beam is applied while the high-temperature gas is being flowed, whereby the melted semiconductor thin film can have low solidification rate, whereby the polycrystal thin film can have large crystal grain diameters and can have good quality of little defects in crystal grains and little twins.Type: ApplicationFiled: March 21, 2001Publication date: November 15, 2001Applicant: FUJITSU, LTD.Inventors: Akito Hara, Kuninori Kitahara
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Patent number: 6287944Abstract: A method of manufacturing a semiconductor device having a polycrystalline semiconductor layer includes the steps of: preparing a base substrate; forming a first semiconductor layer on a surface of the base substrate; forming a first polycrystalline semiconductor layer by applying an energy beam to the first semiconductor layer; etching a surface layer of the first polycrystalline semiconductor layer; and after the etching process, forming a second semiconductor layer on a surface of the first polycrystalline semiconductor layer without exposing the surface of the first polycrystalline semiconductor layer to an atmospheric air. The final polycrystalline semiconductor layer has a high film quality.Type: GrantFiled: August 18, 1999Date of Patent: September 11, 2001Assignee: Fujitsu LimitedInventors: Akito Hara, Kuninori Kitahara, Satoshi Murakami
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Patent number: 6255148Abstract: A polycrystal thin film forming method comprising the step of forming a semiconductor thin film on a substrate 14, and the step of flowing a heated gas to the semiconductor thin film while an energy beam 38 is being applied to the semiconductor thin film at a region to which the gas is being applied to thereby melt the semiconductor film, and crystallizing the semiconductor thin film in its solidification. The energy beam is applied while the high-temperature gas is being flowed, whereby the melted semiconductor thin film can have low solidification rate, whereby the polycrystal thin film can have large crystal grain diameters and can have good quality of little defects in crystal grains and little twins.Type: GrantFiled: June 8, 1999Date of Patent: July 3, 2001Assignee: Fujitsu LimitedInventors: Akito Hara, Kuninori Kitahara
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Patent number: 5970369Abstract: A multilayer polysilicon semiconductor device having a first layer of amorphous semiconductor deposited on the surface of an underlying substrate. The first layer is polycrystallized by applying an energy beam to the first layer. A second layer is deposited on the surface of the polycrystallized first layer, the second layer being made of amorphous semiconductor having the same composition as the first layer or polycrystalline semiconductor. Crystallinity of the second layer is changed by applying an energy beam to the second layer. The substrate may be heated when the energy beam is applied to the second layer.Type: GrantFiled: November 21, 1997Date of Patent: October 19, 1999Assignee: Fujitsu LimitedInventors: Akito Hara, Satoshi Murakami, Kuninori Kitahara
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Patent number: 5641353Abstract: The present invention is to manufacture a low hydrogen-concentration silicon crystal having less micro defects caused from oxygen precipitation generated during an annealing process. Particularly, a silicon crystal including hydrogen concentration lower than 0.55.times.10.sup.11 cm.sup.-3, where the hydrogen concentration dependency is small and the micro defect density is less, may be used for a substrate of semiconductor devices. The low hydrogen-concentration silicon substrate is manufactured by measuring the hydrogen concentrations in a silicon crystal and in a hydrogen-doped silicon crystal having a known hydrogen concentration, where both the silicon crystals have been annealed at an equal condition so as to generate thermal donors therein, and by comparing thus measured hydrogen concentrations.Type: GrantFiled: November 30, 1995Date of Patent: June 24, 1997Assignee: Fujitsu LimitedInventors: Akito Hara, Masaaki Koizuka
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Patent number: 5505157Abstract: The present invention is to manufacture a low hydrogen-concentration silicon crystal having less micro defects caused from oxygen precipitation generated during an annealing process. Particularly, a silicon crystal including hydrogen concentration lower than 0.55.times.10.sup.11 cm.sup.-3, where the hydrogen concentration dependency is small and the micro defect density is less, may be used for a substrate of semiconductor devices. The low hydrogen-concentration silicon substrate is manufactured by measuring the hydrogen concentrations in a silicon crystal and in a hydrogen-doped silicon crystal having a known hydrogen concentration, where both the silicon crystals have been annealed at an equal condition so as to generated thermal donors therein, and by comparing thus measured hydrogen concentrations.Type: GrantFiled: May 26, 1994Date of Patent: April 9, 1996Assignee: Fujitsu LimitedInventors: Akito Hara, Masaaki Koizuka