Patents by Inventor Toyoharu Oohata

Toyoharu Oohata 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: 20040067648
    Abstract: A crystal foundation having dislocations is used to obtain a crystal film of low dislocation density, a crystal substrate, and a semiconductor device. One side of a growth substrate (11) is provided with a crystal layer (13) with a buffer layer (12) in between. The crystal layer (13) has spaces (13a), (13b) in an end of each threading dislocation D1 elongating from below. The threading dislocation D1 is separated from the upper layer by the spaces (13a), (13b), so that each threading dislocation D1 is blocked from propagating to the upper layer. When the displacement of the threading dislocation D1 expressed by Burgers vector is preserved to develop another dislocation, the spaces (13a), (13b) vary the direction of its displacement. As a result, the upper layer above the spaces (13a), (13b) turns crystalline with a low dislocation density.
    Type: Application
    Filed: November 20, 2003
    Publication date: April 8, 2004
    Inventors: Etsuo Morita, Yousuke Murakami, Goshi Biwa, Hiroyuki Okuyama, Masato Doi, Toyoharu Oohata
  • Publication number: 20040051110
    Abstract: Disclosed are a semiconductor light emitting device capable of enhancing a light emergence efficiency at a lower light emergence plane of the device by forming an electrode on a halfway area of a tilt crystal plane and a fabrication method thereof. According to this light emitting device, since light emitted by a light emitting region can be efficiently, totally reflected and a current can be injected only in a good crystalline region for the reason that the halfway area, on which the electrode is formed, of the tilt crystal plane is better in crystallinity than other regions of the tilt crystal plane, it is possible to enhance both a light emergence efficiency and a luminous efficiency, and hence to enhance the light emergence efficiency by an input current.
    Type: Application
    Filed: September 25, 2003
    Publication date: March 18, 2004
    Inventor: Toyoharu Oohata
  • Publication number: 20040048409
    Abstract: Disclosed are a nitride semiconductor device excellent in characteristics, which has a device structure grown into a three-dimensional shape by selective growth, and a method of fabricating the nitride semiconductor device. The nitride semiconductor device according to the present invention includes a crystal layer grown into a three-dimensional shape having a side surface portion (16s) and an upper layer portion (16t), wherein and electrode layer (21) is formed on the upper layer portion via a high resistance region formed by an undoped gallium nitride layer (17) or the like. Since the high resistance region is provided on the upper layer portion (16t), a current flows so as to bypass the high resistance region of the upper layer portion (16t), to form a current path extending mainly along the side surface portion (16s) while avoiding the upper layer portion (16t), thereby suppressing the flow of a current in the upper layer portion (16t) poor in crystallinity.
    Type: Application
    Filed: April 22, 2003
    Publication date: March 11, 2004
    Inventors: Goshi Biwa, Hiroyuki Okuyama, Masato Doi, Toyoharu Oohata
  • Patent number: 6683416
    Abstract: A method of transferring multiple devices arrayed on a first substrate to a second substrate is provided. The devices on the first substrate are covered with a release agent, and a portion of the release agent, positioned on a device to be transferred is selectively removed. The first substrate is placed on a second substrate in such a manner that the devices arrayed on the first substrate face an adhesive layer previously provided on the second substrate. Only the device from which the release agent has been removed, is irradiated with a laser beam from a back side of the first substrate. The second substrate is then peeled from the first substrate, whereby only the device to be transferred is certainly, efficiently, and accurately transferred from the first substrate to the second substrate.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: January 27, 2004
    Assignee: Sony Corporation
    Inventors: Toyoharu Oohata, Katsuhiro Tomoda
  • Publication number: 20040012337
    Abstract: A method of transferring multiple devices arrayed on a first substrate to a second substrate is provided. The devices on the first substrate are covered with a release agent, and a portion of the release agent, positioned on a device to be transferred is selectively removed. The first substrate is placed on a second substrate in such a manner that the devices arrayed on the first substrate face an adhesive layer previously provided on the second substrate. Only the device from which the release agent has been removed, is irradiated with a laser beam from a back side of the first substrate. The second substrate is then peeled from the first substrate, whereby only the device to be transferred is certainly, efficiently, and accurately transferred from the first substrate to the second substrate.
    Type: Application
    Filed: April 19, 2002
    Publication date: January 22, 2004
    Inventors: Toyoharu Oohata, Katsuhiro Tomoda
  • Publication number: 20030183824
    Abstract: In a semiconductor light emitting device configured to extract light through a substrate thereof, an electrode layer is formed on a p-type semiconductor layer (such as p-type GaN layer) formed on an active layer, and a nickel layer is formed as a contact metal layer between the electrode layer and the p-type semiconductor layer and adjusted in thickness not to exceed the intrusion length of light generated in the active layer. Since the nickel layer is sufficiently thin, reflection efficiency can be enhanced.
    Type: Application
    Filed: May 7, 2003
    Publication date: October 2, 2003
    Inventors: Masato Doi, Hiroyuki Okuyama, Goshi Biwa, Toyoharu Oohata
  • Patent number: 6628347
    Abstract: An optical writing type liquid crystal light valve apparatus is composed so as to have at least first and second transparent substates, a photoconductive layer, first and second electrodes which are arranged so as to contract with and sandwich the photoconductive layer or arranged on one surface of the photoconductive layer, an optical reflective layer, a liquid crystal layer and a third electrode. The second electrode is composed of split electrode sections obtained by splitting the second electrode into a plurality of electrode sections. Opposing areas, which face each other via the photoconductive layer, of the photoconductive layer which the first electrode and the split electrode sections of the second electrode are set to be smaller than an area of the split electrode section of the second electrode.
    Type: Grant
    Filed: July 26, 1999
    Date of Patent: September 30, 2003
    Assignee: Sony Corporation
    Inventors: Toyoharu Oohata, Hideharu Nakajima
  • Patent number: 6623560
    Abstract: A crystal growth method includes forming a mask layer capable of impeding crystal growth on a substrate in such a way a first nitride semiconductor layer has irregularities at a surface thereof exposed at a window region opened at a part of the mask layer, and growing a second nitride semiconductor layer over a region including the surface of the mask layer through crystal growth from the irregularities. Through-type dislocations can be reliably prevented from propagation due to the discontinuity of crystals at the irregularities and also to lateral crystal growth.
    Type: Grant
    Filed: July 17, 2001
    Date of Patent: September 23, 2003
    Assignee: Sony Corporation
    Inventors: Goshi Biwa, Hiroyuki Okuyama, Masato Doi, Toyoharu Oohata
  • Patent number: 6613610
    Abstract: An image display unit and a method of producing the image display unit, wherein the image display unit includes an array of a plurality of light emitting devices for displaying an image, and wherein the method of producing the image display unit employs, for example, a space expanding transfer, whereby a first transfer step includes transferring the devices arrayed on a first substrate to a temporary holding member such that the devices are spaced from each other with a pitch larger than a pitch of the devices arrayed on the first substrate, a second holding step includes holding the devices on the temporary holding member, and a third transfer step includes transferring the devices held on the temporary holding member onto a second board such that the devices are spaced from each other with a pitch larger than the pitch of the devices held on the temporary holding member.
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: September 2, 2003
    Assignee: Sony Corporation
    Inventors: Toshiaki Iwafuchi, Toyoharu Oohata, Masato Doi
  • Publication number: 20030160258
    Abstract: A semiconductor crystal layer formed by epitaxial growth on a seed crystal substrate is embedded in an insulating material in the condition where the seed crystal substrate is removed, electrodes are provided respectively on a first surface of the semiconductor crystal layer and a second surface of the semiconductor layer opposite to the first surface, and lead-out electrodes connected to the electrodes are led out to the same surface side of the insulating material. The semiconductor crystal layer functions as a semiconductor light-emitting device or a semiconductor electronic device. The insulating material is, for example, a resin.
    Type: Application
    Filed: December 3, 2002
    Publication date: August 28, 2003
    Applicant: Sony Corporation
    Inventor: Toyoharu Oohata
  • Publication number: 20030157741
    Abstract: An inexpensive display unit having a sufficient luminance and a method of fabricating the display unit are disposed, wherein micro-sized semiconductor light emitting devices are fixedly arrayed on a plane of a base body of the display unit at intervals. Micro-sized GaN based semiconductor light emitting devices (11) formed by selective growth are each buried in a first insulating layer (21) made from an epoxy resin except an upper end portion and a lower end surface thereof, and electrodes (18) and (19) of each of the light emitting devices (11) are extracted. These light emitting devices (11) are fixedly arrayed on the upper plane of the base body (31) at intervals.
    Type: Application
    Filed: March 12, 2003
    Publication date: August 21, 2003
    Inventors: Toyoharu Oohata, Hideharu Nakajima, Yoshiyuki Yanagisawa, Toshiaki Iwafuchi
  • Publication number: 20030150843
    Abstract: Disclosed are a crystal layer separation method capable of separating a crystal layer formed on a substrate therefrom without occurrence of any crack, and a laser irradiation method used therefor, and a method of fabricating devices using the same. The crystal layer separation method includes the step of separating a crystal layer made from a GaN based compound formed on a sapphire substrate therefrom by irradiating the crystal layer with a laser beam from the back surface of the substrate, wherein the crystal layer is irradiated with the laser beam in a line-shape. In this method, an irradiation width of the laser beam is preferably equal to or less than a thickness of the crystal layer, and the laser beam preferably has a light intensity distribution smoothened in the width direction.
    Type: Application
    Filed: December 3, 2002
    Publication date: August 14, 2003
    Applicant: Sony Corporation
    Inventors: Masato Doi, Toshiaki Iwafuchi, Toyoharu Oohata
  • Publication number: 20030107047
    Abstract: A semiconductor light-emitting element having a structure that does not complicate a fabrication process, can be formed in high precision and does not invite any degradation of crystallinity is provided. A light-emitting element is formed, which includes a selective crystal growth layer formed by selectively growing a compound semiconductor of a Wurtzite type, and a clad layer of a first conduction type, an active layer and a clad layer of a second conduction type, which are formed on the selective crystal growth layer wherein the active layer is formed so that the active layer extends in parallel to different crystal planes, the active layer is larger in size than a diffusion length of a constituent atom of a mixed crystal, or the active layer has a difference in at least one of a composition and a thickness thereof, thereby forming the active layer having a plurality of light-emitting wavelength region whose emission wavelengths differ from one another.
    Type: Application
    Filed: July 23, 2002
    Publication date: June 12, 2003
    Inventors: Hiroyuki Okuyama, Masato Doi, Goshi Biwa, Toyoharu Oohata
  • Patent number: 6576571
    Abstract: Disclosed herein is a process for vapor phase growth of gallium nitride compound semiconductor which yields uniform crystal layers with good reproducibility. The process comprises forming a first nitride semiconductor layer on a substrate, forming thereon a protective film for crystal growth prevention in such a way that it has partly open window regions through which the first nitride semiconductor layer is exposed, forming a second nitride semiconductor layer by selective growth from the first nitride semiconductor layer at a crystal growth starting temperature, and continuing crystal growth at a temperature higher than the crystal growth starting temperature. The vapor phase growth at a low temperature yields a uniform crystal layer, and the ensuing vapor phase growth at a raised temperature yields a uniform crystal layer with good reproducibility in conformity with the first crystal layer.
    Type: Grant
    Filed: July 31, 2001
    Date of Patent: June 10, 2003
    Assignee: Sony Corporation
    Inventors: Goshi Biwa, Hiroyuki Okuyama, Masato Doi, Toyoharu Oohata
  • Publication number: 20030087467
    Abstract: A semiconductor light emitting device includes a crystal growth layer, and a crystal layer composed of a first conductive type layer, an active layer, and a second conductive type layer. The crystal layer is provided on the upper side of the crystal growth layer. In this device, a back plane of the crystal growth layer has irregularities. Since light generated in the device is prevented from being totally reflected from the back plane of the crystal growth layer, the light emergence efficiency of the device can be increased.
    Type: Application
    Filed: July 10, 2002
    Publication date: May 8, 2003
    Inventors: Toyoharu Oohata, Masato Doi
  • Publication number: 20030087476
    Abstract: A first adhesive layer is provided on a base substrate, and multiple devices are arranged on the first adhesive layer. The first adhesive layer is irradiated with laser light from the back side of the base substrate, only at positions corresponding to the devices to be transferred, by use of a mask, whereby the adhesive force of the first adhesive layer is lowered only at these positions, and only these devices are made releasable from the base substrate. A transfer substrate provided with a second adhesive layer and the base substrate are so disposed that the devices and the second adhesive layer are opposite to each other and pressed against each other. When the transfer substrate is stripped from the base substrate, only the devices to be transferred are selectively transferred onto the transfer substrate.
    Type: Application
    Filed: September 6, 2002
    Publication date: May 8, 2003
    Inventors: Toyoharu Oohata, Toshiaki Iwafuchi, Hisashi Ohba
  • Publication number: 20030045042
    Abstract: A first conductive type layer having a band gap energy smaller than that of an under growth layer formed on a substrate is formed by selective growth from an opening portion formed in the under growth layer, and an active layer and a second conductive type layer are stacked on the first conductive type layer, to form a stacked structure. When such a stacked structure for forming a semiconductor device is irradiated with laser beams having an energy value between the band gap energies of the under growth layer and the first conductive type layer, abrasion occurs at a first conductive type layer side interface between the under growth layer and the first conductive type layer, so that the stacked structure is peeled from the substrate and the under growth layer and simultaneously isolated from another stacked structure for forming another semiconductor device.
    Type: Application
    Filed: August 2, 2002
    Publication date: March 6, 2003
    Inventors: Goshi Biwa, Hiroyuki Okuyama, Masato Doi, Toyoharu Oohata
  • Patent number: D472529
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: April 1, 2003
    Assignee: Sony Corporation
    Inventors: Hiroyuki Okuyama, Masato Doi, Goshi Biwa, Toyoharu Oohata
  • Patent number: D472531
    Type: Grant
    Filed: June 25, 2002
    Date of Patent: April 1, 2003
    Assignee: Sony Corporation
    Inventors: Hiroyuki Okuyama, Masato Doi, Goshi Biwa, Toyoharu Oohata
  • Patent number: D485242
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: January 13, 2004
    Assignee: Sony Corporation
    Inventors: Toshiaki Iwafuchi, Toyoharu Oohata, Masato Doi