Patents by Inventor Koji Kobashi

Koji Kobashi 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).

  • Patent number: 5757344
    Abstract: Disclosed is planar and vertical cold cathode emitter elements including an semiconducting diamond emitter portion having a high thermal resistance and a high breakdown voltage, thereby suppressing the deterioration of the electron emission characteristics and enabling the operation with a high electric power.
    Type: Grant
    Filed: September 30, 1992
    Date of Patent: May 26, 1998
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koichi Miyata, Kozo Nishimura, Koji Kobashi
  • Patent number: 5755879
    Abstract: A method is presented to manufacture substrates for growing monocrystalline diamond films by chemical vapor deposition (CVD) on large area at low cost. The substrate materials are either Pt or its alloys, which have been subject to a single or multiple cycle of cleaning, roller press, and high temperature annealing processes to make the thickness of the substrate materials to 0.5 mm or less, or most preferably to 0.2 mm or less, so that either (111) crystal surfaces or inclined crystal surfaces with angular deviations within .+-.10 degrees from (111), or both, appear on the entire surfaces or at least part of the surfaces of the substrates. The annealing is carried out at a temperature above 800.degree. C. The present invention will make it possible to markedly improve various characteristics of diamond films, and hence put them into practical use.
    Type: Grant
    Filed: November 17, 1995
    Date of Patent: May 26, 1998
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Yoshihiro Shintani, Takeshi Tachibana, Kozo Nishimura, Koichi Miyata, Yoshihiro Yokota, Koji Kobashi
  • Patent number: 5743957
    Abstract: A method of forming a single crystal diamond film in which a single crystal diamond film of large area can be formed at low cost, thereby making it possible to realize a large improvement in the properties of the diamond and also making possible the practical use of diamond in a wide range of applications thereof, said method comprising the steps of: first vapor-depositing a platinum film 2 on a first substrate 1, pressing a second substrate 3 onto the platinum film 2, and carrying out annealing in a vacuum. Next the platinum film 2 and the first substrate 1 are mechanically separated from each other, and the join surface 2a of the platinum film that had once been joined to the first substrate 1 is subjected to a surface scratching treatment, after which diamond is formed by gas-phase synthesis on this join face 2a. A single crystal diamond film is obtained in this way. In the case that the vapor-deposited platinum film has a thickness of no less than 20 .mu.
    Type: Grant
    Filed: July 16, 1996
    Date of Patent: April 28, 1998
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventor: Koji Kobashi
  • Patent number: 5529846
    Abstract: The present invention relates to a heat dissipating substrate with a highly-oriented diamond film of a low crystal inclination and a low density grain boundaries and having a significantly high thermal conductivity. At least 90% of the surface area of the highly-oriented diamond film is covered with either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles, which represent the orientations of the crystals, between adjacent (100) or (111) crystal planes, simultaneously satisfies the following relationship: .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree., and .vertline..DELTA..gamma..vertline..ltoreq.5.degree.. In addition, this highly-oriented diamond film can be grown on a non-diamond substrates, and therefore the diamond film with a large surface area can be obtained. Thus, the present invention provides the heat dissipating substrate with an excellent thermal conductivity at low cost.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: June 25, 1996
    Assignee: Kobe Steel USA, Inc.
    Inventors: Kazushi Hayashi, Koji Kobashi, Jesko A. von Windheim
  • Patent number: 5523588
    Abstract: A diamond film field effect transistor, excellent in characteristics and a method of manufacturing the transistor, in which a contact resistance between electrodes and respective source and drain region is small. The transistor has a channel layer of a p-layer made of semiconducting diamond, an i-layer made of high resistance diamond as a gate insulating layer, which is formed on the channel layer, a gate electrode film formed on the i-layer and a source region and a drain region formed on the surface of the i-layer in self-alignment to the gate electrode film by ion implantation using the gate electrode film, side walls and a protective film as masks.
    Type: Grant
    Filed: July 6, 1994
    Date of Patent: June 4, 1996
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Kozo Nishimura, Hisahi Koyama, Koji Kobashi
  • Patent number: 5523160
    Abstract: The highly-oriented diamond film is a diamond film formed by chemical vapor deposition, with at least 95% of its area consisting of either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles {.alpha., .beta., .gamma.} between the adjacent crystals satisfying (.vertline..DELTA..alpha..vertline..ltoreq.1.degree., .vertline..DELTA..beta..vertline..ltoreq.1.degree. and .vertline..DELTA..gamma..vertline..ltoreq.1.degree.) simultaneously. Thus obtained highly-oriented diamond film has few grain boundaries and high carrier mobility. And the area of the diamond film can be large.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: June 4, 1996
    Assignee: Kobe Steel USA, Inc.
    Inventors: Koji Kobashi, Kozo Nishimura, Koichi Miyata, Takeshi Tachibana, Brian R. Stoner
  • Patent number: 5432357
    Abstract: A pair of electrodes 3 are first formed on a substrate. Subsequently, an undoped diamond film is selectively deposited between the above electrodes. A B-doped diamond film is then selectively formed on both the insulating diamond film and part of each electrode. The substrate may be contained in a container provided with an opening portion from which only the B-doped diamond film is exposed.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: July 11, 1995
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Rie Kato, Koji Kobashi
  • Patent number: 5424561
    Abstract: A magnetic sensor element using highly-oriented diamond film comprises a magnetic detecting part, at least a pair of main current electrodes for flowing a main current and generating the Hall electromotive force at the magnetic detecting part, and detection electrodes for detecting said Hall electromotive force. Said magnetic detecting part is formed of a highly-oriented diamond film grown by chemical vapor deposition, at least 90% of which consists of either (100) or (111) crystal planes. Between the adjacent crystal planes, the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles {.alpha., .beta., .gamma.} which represent the orientation of the crystal planes, satisfy the following relations simultaneously: .vertline..DELTA..alpha..vertline..ltoreq.10.degree., .vertline..DELTA..beta..vertline..ltoreq.10.degree. and .vertline..DELTA..gamma..vertline..ltoreq.10 .degree..
    Type: Grant
    Filed: September 8, 1994
    Date of Patent: June 13, 1995
    Assignee: Kobe Steel USA Inc.
    Inventors: Takeshi Tachibana, Kazushi Hayashi, Koji Kobashi, Bradley A. Fox, Jesko A. von Windheim, David L. Dreifus, Brian R. Stoner
  • Patent number: 5402029
    Abstract: A surface acoustic wave device uses a highly oriented diamond film with a planar surface, increasing the propagating velocity of a surface acoustic wave, and fabricating many devices on a large area without polishing processes. The surface acoustic wave device includes the highly oriented diamond films, a piezoelectric film and electrodes which are formed on the diamond film. In the highly oriented diamond film, 80% or more of the surface area of the diamond film is composed of the (100) faces or (111) faces of diamond; and the difference {.DELTA..alpha.,.DELTA..beta.,.DELTA..gamma.} between the Euler angles {.alpha.,.beta.,.gamma.} expressing the crystal orientations of the adjacent (100) or (111) faces of the diamond film simultaneously satisfies the relations of .vertline..DELTA..alpha..vertline..ltoreq.10.degree., .vertline..DELTA..beta..vertline..ltoreq.10.degree., and .vertline..DELTA..gamma..vertline..ltoreq.10.degree..
    Type: Grant
    Filed: May 6, 1994
    Date of Patent: March 28, 1995
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Rie Nakamura, Koji Kobashi
  • Patent number: 5373172
    Abstract: A semiconducting diamond electroluminescence element comprises an electrically conductive substrate, a semiconducting diamond layer formed on the substrate, an insulating diamond layer formed on the semiconducting diamond layer, a front electrode formed on the insulating diamond layer, and a back electrode formed on the conductive substrate in ohmic contact with the same. The color of light to be emitted by the semiconducting diamond electroluminescence element can readily be determined by changing the impurity content in the semiconducting diamond layer. The luminescence intensity of the semiconducting diamond electroluminescence element can readily be changed by changing the voltage applied across the front and back electrodes without entailing dielectric breakdown.
    Type: Grant
    Filed: January 4, 1993
    Date of Patent: December 13, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koji Kobashi, Koichi Miyata, Kazuo Kumagai, Shigeaki Miyauchi, Yuichi Matsui
  • Patent number: 5358754
    Abstract: A method for forming diamond films by vapor phase synthesis comprising a process of forming the diamond films on a substrate by direct current discharge plasma, in an atmosphere of a reaction gas including a gas containing at least carbon and hydrogen, or in an atmosphere of a mixed gas containing at least a carbon-containing gas and a hydrogen gas, at a gas pressure between 0.1 and 5 Torr and a substrate temperature between 300.degree. and 1000.degree. C.
    Type: Grant
    Filed: July 6, 1992
    Date of Patent: October 25, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koji Kobashi, Shigeaki Miyauchi, Kozo Nishimura, Kazuo Kumagai, Rie Kato
  • Patent number: 5353737
    Abstract: Disclosed is a method for forming a diamond film on a substrate by vapor-phase synthesis using a reaction gas which contains B.sub.2 H.sub.6 and O.sub.2 with a gas concentration ratio (volume %) of ([B.sub.2 H.sub.6 ]/[O.sub.2 ]).gtoreq.1.times.10.sup.-4 in addition to a hydrocarbon gas in hydrogen. By this invention, it is possible to form p-type semiconducting diamond films having an excellent crystallinity and desired electric characteristics.
    Type: Grant
    Filed: April 16, 1993
    Date of Patent: October 11, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Hisashi Koyama, Koichi Miyata, Koji Kobashi
  • Patent number: 5352908
    Abstract: A diamond Schottky diode including an electrically conductive substrate, a multi-layer structure of a semiconducting diamond layer and an insulating diamond layer, and a metal electrode. This diode has a greater potential barrier under a reversed bias and hence exhibits better rectifying characteristics with a smaller reverse current.
    Type: Grant
    Filed: November 3, 1993
    Date of Patent: October 4, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koji Kobashi, Koichi Miyata, Kozo Nishimura
  • Patent number: 5309000
    Abstract: A is a heat-resisting ohmic electrode on diamond film, including: a p-type semiconducting diamond film; a boron-doped diamond layer provided on the semiconducting diamond film; and an electrode element made of p-type Si selectively formed on the boron-doped diamond layer; wherein the boron concentration in the boron-doped diamond layer is from 1.0.times.10.sup.19 to 1.8.times.10.sup.23 cm.sup.-3, and at least one impurity selected from the group consisting of B, Al and Ga is doped in the electrode element with a concentration from 1.0.times.10.sup.20 to 5.0.times.10.sup.22 cm.sup.-3. The ohmic electrode on diamond film is applicable for electronic devices operative at high temperature.
    Type: Grant
    Filed: April 22, 1993
    Date of Patent: May 3, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Kimitsugu Saito, Koji Kobashi, Kozo Nishimura, Koichi Miyata
  • Patent number: 5304461
    Abstract: Thin diamond films can be selectively deposited imagewise on a substrate by gas phase synthesis. The substrate may be either a silicon substrate or a basal thin diamond film formed beforehand on a substrate by gas phase synthesis. Where a silicon substrate is used, its surface is first abraded to give a surface roughness suitable for gas phase synthesis of diamond. When a basal thin diamond film is used, a coating material capable of withstanding a temperature higher than a substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond is needed to cover areas other than where the thin diamond film is to be newly formed. When a lift-off method is used, a thin masking film having a melting point higher than a temperature to be employed for gas phase synthesis of diamond can also be used in place of the coating material described above.
    Type: Grant
    Filed: March 9, 1992
    Date of Patent: April 19, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Takayoshi Inoue, Hiroyuki Tachibana, Akimitsu Nakaue, Kazuo Kumagai, Koichi Miyata, Koji Kobashi
  • Patent number: 5298766
    Abstract: A diamond heterojunction diode having an improved rectifying characteristics with a small reverse current and a large forward current. Three layers are formed on a low-resistance p-type silicon substrate by the microwave plasma CVD in the order of a B-doped p type semiconducting diamond layer, an insulating undoped diamond layer (thinner than 1 .mu.m), and an n-type semiconducting silicon layer. Ohmic electrodes are formed on the front side of a n-type semiconducting silicon layer and the back side of a substrate. Under a forward bias, the electric field is applied to the intermediate insulating layer to accelerate the transport of holes and electrons. Under a reversed bias, the energy band has a notch as well as a potential barrier due to the intermediate layer thus preventing holes from transporting from the n-type semiconducting diamond layer to the p-type semiconducting diamond layer, resulting in the improved rectifying characteristics.
    Type: Grant
    Filed: March 20, 1992
    Date of Patent: March 29, 1994
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koji Kobashi, Kozo Nishimura, Shigeaki Miyauchi, Kazuo Kumagai, Rie Katoh
  • Patent number: 5173761
    Abstract: A method and apparatus for contructing diamond semiconductor structures made of polycrystalline diamond thin films is disclosed. The use of a polycrystalline diamond deposition on a substrate material provides an advantage that any substrate material may be used and the ability to use polycrystalline diamond as a material is brought about through the use of an undoped diamond layer acting as an insulating layer which is formed on a boron-doped layer. Because of the structure, ion implantation can be employed to reduce the ohmic contact resistance. The ion implantation also provides that the entire structure can be made using a deep implant to form a channel layer which allows the insulating gate structure to be formed as an integral part of the device. The buried channel can be doped through the use of several implantation steps through the insulating undoped layer.
    Type: Grant
    Filed: January 28, 1991
    Date of Patent: December 22, 1992
    Assignee: Kobe Steel USA Inc., Electronic Materials Center
    Inventors: David L. Dreifus, Kumar Das, Koichi Miyata, Koji Kobashi
  • Patent number: 5160405
    Abstract: Described is an etching method of a diamond film which comprises providing a diamond film in an atmosphere of a gas containing at least oxygen and/or hydrogen and subjecting the diamond film to an irradiation of an electron beam generated by direct current discharge through a pattern of a mask. In this condition, when the diamond film is contacted with the plasma produced by the electron beam in the atmosphere, the unmasked areas are irradiated by the electron beam, and converted to graphite. The graphite is more readily etched by the plasma, so that the diamond film can be etched at a high rate. The etching through a mask ensures a fine etched pattern of the diamond film. In addition, a diamond film with a large area can be etched by this method.
    Type: Grant
    Filed: March 18, 1991
    Date of Patent: November 3, 1992
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Shigeaki Miyauchi, Koichi Miyata, Kazuo Kumagai, Koji Kobashi
  • Patent number: 5107315
    Abstract: Disclosed herein is a MIS type diamond field-effect transistor comprising a diamond semiconductor layer provided as an active layer by chemical vapor deposition (CVD), and a diamond insulator layer provided on the diamond semiconductor layer also by CVD, a gate electrode being formed on the diamond insulator layer, wherein a diamond insulator undercoat is provided on a non-diamond substrate by CVD, and the diamond semiconductor layer and the diamond insulator layer are sequentially provided on the diamond insulator undercoat. The MIS type diamond field-effect transistor with this structure ensures that in the manufacture thereof, a diamond insulator undercoat of large area can be formed on a non-diamond substrate of CVD, whereby a large number of elemental devices can be fabricated simultaneously.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: April 21, 1992
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Kazuo Kumagai, Koichi Miyata, Shigeaki Miyauchi, Yuichi Matsui, Koji Kobashi
  • Patent number: 5086014
    Abstract: A schottky diode manufacturing process employing diamond film comprises forming a B-doped p-type polycrystalline diamond film on a low-resistance p-type Si substrate by CVD using a source gas consisting of CH.sub.4, H.sub.2 and B.sub.2 H.sub.6, forming an ohmic contact on the back of the p-type Si substrate, and forming a metal electrode of Al, Pt Au, Ti or W on the B-doped p-type polycrystalline diamond film. The B/C concentration ratio of the source gas is greater than 0.01 ppm and less than 20 ppm.
    Type: Grant
    Filed: September 18, 1990
    Date of Patent: February 4, 1992
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Koichi Miyata, Kazuo Kumagai, Koji Kobashi, Yuichi Matsui, Akimitsu Nakaue