Patents by Inventor Yoshiki Nishibayashi
Yoshiki Nishibayashi 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: 5729074Abstract: A micro mechanical component of the present invention comprises a base, and at least one drive portion supported on the base and relatively driving to the base, in which the drive portion is formed from a diamond layer. Thus, because the drive portion has excellent mechanical strength and modulus of elasticity, the operational performance can be greatly improved as a micro mechanical component processed in a fine shape, from the conventional level. Further, because the drive portion exhibits excellent device characteristics under severe circumstances, the range of applications as a micro mechanical component can be widely expanded from the conventional range.Type: GrantFiled: March 20, 1995Date of Patent: March 17, 1998Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiromu Shiomi, Yoshiki Nishibayashi, Shin-ichi Shikata
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Patent number: 5670796Abstract: A semiconductor device has a structure in which doped layers and undoped layers are alternately stacked and is constituted by (a) a semi-insulating substrate, (b) undoped layers consisting of a substantially undoped diamond material, and (c) thin doped layers formed between the undoped layers and consisting of a diamond material doped with B as an impurity. Stable operation characteristics can be obtained within a temperature range from room temperature to a high temperature while a semiconductor material having a deep impurity level is used.Type: GrantFiled: March 20, 1996Date of Patent: September 23, 1997Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Shin-ichi Shikata, Naoji Fujimori, Takeshi Kobayashi
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Patent number: 5668382Abstract: An ohmic electorde of the present invention comprises a contact electrode layer formed on a p-type diamond semiconductor layer formed on a substrate so as to be in ohmic contact with the p-type diamond semiconductor layer and to have low contact resistance and high heat resistance, and a lead electrode layer formed on the contact electrode layer so as to have low lead wire resistance and high heat resistance. Specifically, the contact electrode layer is made of either a carbide of at least one metal selected from a metal group comprising Ti, Zr, and Hf, or a carbide of an alloy containing at least one metal selected from the metal group. Since the carbide of the metal or alloy forming the contact electrode layer is stabler in respect of energy because of reduced formation enthalpy than the metal or alloy itself, it is very unlikely to diffuse.Type: GrantFiled: June 28, 1996Date of Patent: September 16, 1997Assignee: Sumitomo Electric Industries, Ltd.Inventors: Naohiro Toda, Yoshiki Nishibayashi, Tadashi Tomikawa, Shin-ichi Shikata
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Patent number: 5663595Abstract: A diamond heat sink of the present invention comprises:a support layer consisting of substantially undoped vapor phase synthetic diamond;a heat sensitive layer consisting of doped vapor phase synthetic diamond formed on the surface of the support layer;an insulation layer consisting of substantially undoped vapor phase synthetic diamond formed on a predetermined region of the heat sensitive layer; andan electrode formed on the heat sensitive layer. The electrode typically consists of a metal, preferably Ti/Mo/Au or Ti/Pt/Au.The diamond heat sink of the present invention may further include a highly-doped layer for creating Ohmic contacts with the metal electrode, which is made of the vapor phase synthetic diamond having high impurity levels, and which is disposed between the metal electrode and the heat sensitive layer.Type: GrantFiled: July 31, 1995Date of Patent: September 2, 1997Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiromu Shiomi, Hideaki Nakahata, Yoshiki Nishibayashi, Shin-ichi Shikata
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Patent number: 5600156Abstract: A diamond semiconductor device of the present invention comprises an n-type diamond layer to which an n-type dopant is doped at high concentration so that metal conduction dominates, a p-type diamond layer to which a p-type dopant is doped at high concentration so that metal conduction dominates, and a high resistance diamond layer formed between the n-type diamond layer and the p-type diamond layer. Here, the thickness and the doping concentration of the high resistance diamond layer are values at which semiconductor conduction dominates. Then, in a case that an applied voltage is forward bias, electrons are injected from the n-type region to the p-type region through the conduction band of the high resistance region, and holes are injected from the p-type region to the n-type region through the valance band of the high resistance region, so that a current flows.Type: GrantFiled: September 8, 1994Date of Patent: February 4, 1997Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Tadashi Tomikawa, Shin-ichi Shikata
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Patent number: 5552613Abstract: An electron device of the present invention comprises an i-type diamond layer formed on a substrate, and an n-type diamond layer formed on the i-type diamond layer and having a first surface region formed flatly and a second surface region containing an emitter portion, which are set in a vacuum container, in which the emitter portion formed of the n-type diamond has a bottom area 10 or less .mu.m square and projects relative to the first surface region. In the n-type diamond layer, a difference is fine between the conduction band and the vacuum level. Also, since the n-type diamond layer is doped with an n-type dopant in a high concentration, metal conduction is dominant as conduction of electrons. Therefore, setting the temperature of the substrate at a predetermined temperature and generating an electric field near the surface of the emitter portion, electrons are emitted with a high efficiency from the tip portion of the emitter portion into the vacuum.Type: GrantFiled: September 22, 1994Date of Patent: September 3, 1996Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Tadashi Tomikawa, Shin-ichi Shikata
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Patent number: 5527735Abstract: N-type c-BN is a heat-resistant material with a wide band gap. Ohmic electrodes are indispensable for making semiconductor devices utilizing n-type c-BN. The electrodes proposed so far are likely to deteriorate in an atmosphere of high temperature. The degradation of electrodes hinders the production of semiconductor devices utilizing c-BN. A heat-resistant ohmic electrode is produced by forming a low contact resistance layer of a boride or a nitride of Ti, Zr or Hf on a heated c-BN and by covering the low resistance layer by an Au layer. Otherwise an ohmic electrode is produced by forming a low contact resistance layer of one of Ti, Zr, Hf, etc. on c-BN, making a diffusion barrier layer of W, Mo, Ta or Pt and depositing an Au layer on the diffusion barrier layer.Type: GrantFiled: April 25, 1995Date of Patent: June 18, 1996Assignees: Sumitomo Electric Industries, Ltd., Research Institute of Innovative Technology for the EarthInventors: Tadashi Tomikawa, Yoshiki Nishibayashi, Shin-ichi Shikata
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Patent number: 5500077Abstract: A method of flattening diamond, including: forming a flat coating comprising a material different from diamond, on a surface of diamond having unevenness; and removing the coating and the unevenness of the surface of diamond by dry etching under a condition such that both of the coating and the diamond can be etched, thereby to smooth the surface of the diamond.Type: GrantFiled: March 8, 1994Date of Patent: March 19, 1996Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Shinichi Shikata
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Patent number: 5500393Abstract: The characteristics of a Schottky junction between diamond and metal causes the diode using the Schottky junction to have a large leakage reverse current and n-value far bigger than 1. A surface of diamond on which a Schottky junction shall be formed is pretreated by oxygen plasma or halogen plasma. The oxygen plasma or hydrogen plasma improves the surface state of the diamond by decoupling the surface C--C bonds and endowing the resulting extra bonds with hydrogen atoms, normalizing the superlattice structure at the surface. Pretreatment of the diamond by the oxygen or halogen plasma improves the diode properties; decreasing reverse current, increasing forward current and decreasing the n-value nearer to 1.Type: GrantFiled: January 21, 1994Date of Patent: March 19, 1996Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Hiromu Shiomi, Naoji Fujimori
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Patent number: 5420879Abstract: A solid state laser includes a diamond crystal as a medium of laser beam emission, which generates a laser beam having a wavelength of 225 to 300 nm through exciton light emission.Type: GrantFiled: September 15, 1993Date of Patent: May 30, 1995Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiroshi Kawarada, Takahiro Imai, Yoshiki Nishibayashi, Naoji Fujimori
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Patent number: 5417798Abstract: Reactive ion etching of diamond using oxygen plasma roughs the surface of diamond due to the strong bombardment of oxygen ions with various kinetic energy. A metal grid with holes is installed between the oxygen plasma and the diamond. Since the metal grid is biased in order to prevent oxygen plasma from being in contact with the diamond, the oxygen ions which have passed the grid will bombard the surface of the diamond with common, low energy. The etched surface becomes smooth.Type: GrantFiled: January 22, 1992Date of Patent: May 23, 1995Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Naoji Fujimori
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Patent number: 5382809Abstract: A semiconductor device having an MISFET-like structure. The semiconductor device comprises: an p-type semiconductor diamond layer disposed on an insulating diamond substrate for providing a channel region; and a drain electrode, a source electrode and a gate electrode disposed on the p-type diamond layer. An intermediate region comprising diamond doped with at least an n-type dopant such as nitrogen atoms, is formed between the channel region and the gate electrode.Type: GrantFiled: September 9, 1993Date of Patent: January 17, 1995Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Tadashi Tomikawa, Shinichi Shikata
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Patent number: 5344526Abstract: A diamond surface is selectively etched by forming a mask on a surface of diamond, and etching the diamond surface with a mixture of oxygen-containing gas and an inert gas, in which a concentration of oxygen in terms of O.sub.2 is from 0.01 to 20% based on the whole volume of the mixture.Type: GrantFiled: September 16, 1993Date of Patent: September 6, 1994Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Shinichi Shikata
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Patent number: 5252840Abstract: A semiconductor device having active parts made from semiconductor diamond. The active parts include a high doped diamond layer for supplying free carriers and a non- or low doped diamond layer for giving the free carriers a conductive region. The free carriers are transferred from the high doped diamond layer to the non- or low doped diamond layer by diffusion or an applied electric field. Since the free carriers move at high speeds in the non- or low doped diamond layer without being scattered by dopant atoms, the semiconductor device is applicable to high frequency devices with stability against a change in temperature.Type: GrantFiled: May 9, 1991Date of Patent: October 12, 1993Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiromu Shiomi, Yoshiki Nishibayashi, Naoji Fujimori
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Patent number: 5243199Abstract: Improvement of a high frequency device having metal layers, active semiconductor layers and other semiconductor layers which make use of carrier avalanche or carrier injection induced by a reverse bias voltage for amplification or oscillation of high frequency waves. The active semiconductor layers are made of semiconductor diamond. High heat conductivity and high insulation breakdown voltage of diamond heighten the output power of oscillation or amplification.Type: GrantFiled: June 24, 1992Date of Patent: September 7, 1993Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiromu Shiomi, Yoshiki Nishibayashi, Naoji Fujimori
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Patent number: 5162886Abstract: A Hall device having an active part made from semiconductor diamond. The Hall device works even at high temperature or in corrosive atmosphere. Boron doped diamond is suitable for controlling the acceptor concentration.Type: GrantFiled: May 9, 1991Date of Patent: November 10, 1992Assignee: Sumitomo Electric Industries Ltd.Inventors: Yoshiki Nishibayashi, Hideaki Nakahata, Hiromu Shiomi, Naoji Fujimori
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Patent number: 5132749Abstract: Doping a dopant into a diamond semiconductor causes lattice defects. The pn junction diode or the Schottky junction diode made from diamond has low break down voltage and high reverse leakage current owing to the lattice defects. A non-doped or low doped diamond layer with high resistivity is epitaxially grown between the N-type diamond layer and the p-type diamond layer in the pn junction diode or between the metal layer and the doped diamond layer in the Schottky diode. The intermediate layer heightens the break down voltage and decreases the reverse leakage current.Type: GrantFiled: March 6, 1991Date of Patent: July 21, 1992Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiki Nishibayashi, Hiromu Shiomi, Maoji Fujimori