Patents by Inventor Shunji Nakata

Shunji Nakata 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: 6168962
    Abstract: Disclosed is a method of manufacturing a semiconductor light emitting device. Semiconductor overlying layers are formed on a substrate in a state of a wafer so that a light emitting area is provided therein. The semiconductor overlying layers includes first and second conductivity type layers. Part of the semiconductor overlying layers including the first conductivity type layer on a surface thereof is removed so as to expose part of the second conductivity type layer. Electrodes are formed, for each chip, respectively in connection with the surface of the first conductivity type layer and the surface of the exposed second conductivity type layer. The wafer is divided into individual chips. The exposed areas of the second conductivity type semiconductor layer is provided only part of a peripheral area of the chip so that the first conductivity type semiconductor layer is directly separated during dividing the wafer into individual chips.
    Type: Grant
    Filed: January 23, 1998
    Date of Patent: January 2, 2001
    Assignee: Rohm Co., Ltd.
    Inventors: Norikazu Itoh, Shunji Nakata, Yukio Shakuda, Masayuki Sonobe, Tsuyoshi Tsutsui
  • Patent number: 6163037
    Abstract: An active layer is sandwiched between the n-type cladding layer and the p-type cladding layer, forming a light emitting layer forming portion. The n-type cladding layer has a carrier concentration of non-doped or less than 5.times.10.sup.17 cm.sup.-3 on a side thereof close to the active layer, and a carrier concentration of 7.times.10.sup.17 -7.times.10.sup.18 cm .sup.-3 on a side thereof remote from the active layer. With this structure, it is possible to suppress to a minimum the deterioration of crystallinity at an interface between the active layer and the n-type cladding layer as well as in the active layer. thereby providing a semiconductor light emitting device high in brightness.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: December 19, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Yukio Matsumoto, Shunji Nakata, Yukio Shakuda
  • Patent number: 6156584
    Abstract: Deposited on a wafer-like substrate for forming a plurality of light emitting device chips is a semiconductor layer laminate with a different property from that of the substrate. Then, electrodes are provided on and in electric connection with a top semiconductor layer of a first conductivity type of the semiconductor layer laminate, and on and in electric connection with a semiconductor layer of a second conductivity type, exposed by locally etching the semiconductor layer laminate, in association with the individual chips. Then, the semiconductor layer laminate is etched at boundary portions between the chips to expose the substrate, and the substrate is broken at the exposed portions into the chips. As the semiconductor layer laminate is etched out at the boundary portions between the chips before breaking the wafer, breaking can be facilitated without damaging the light emitting portions of the semiconductor layer laminate. This helps provide high-performance semiconductor light emitting devices.
    Type: Grant
    Filed: March 26, 1998
    Date of Patent: December 5, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Norikazu Itoh, Shunji Nakata, Yukio Shakuda, Masayuki Sonobe, Tsuyoshi Tsutsui
  • Patent number: 6107644
    Abstract: A semiconductor light emitting device has semiconductor layers including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer formed on a substrate. A first electrode is formed in electrical connection with the first conductivity type semiconductor layer on a surface side of the semiconductor layers. The second conductivity type semiconductor layer is exposed by partly etch-removing an end portion of the semiconductor layers. A second electrode is provided in electrical connection with the exposed second conductivity type layer. The first and second electrodes are formed such that the electrodes are in parallel, in plan form, with each other at opposite portions thereof. As a result, the current path is constant in electric resistance, providing a semiconductor light emitting device that is constant in brightness, long in service life and high in brightness.
    Type: Grant
    Filed: January 23, 1998
    Date of Patent: August 22, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Yukio Shakuda, Shunji Nakata, Masayuki Sonobe, Tsuyoshi Tsutsui, Norikazu Itoh
  • Patent number: 6107647
    Abstract: A semiconductor light emitting device has a light emitting layer forming portion formed on the substrate and having an n-type layer and a p-type layer to provide a light emitting layer. A window layer is formed on a surface side of the light emitting layer forming portion. The window layer is formed of AlyGal-yAs (0.6.ltoreq.y.ltoreq.0.8) auto-doped in a carrier concentration of 5.times.10.sup.18 -3.times.10.sup.19 cm.sup.-3. The resulting semiconductor light emitting device is free of degradation in crystallinity due to p-type impurity doping, thereby provide a high light emitting efficiency and brightness without encountering device degradation or damage.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: August 22, 2000
    Assignee: Rohm Co. Ltd.
    Inventors: Yukio Matsumoto, Shunji Nakata, Yukio Shakuda
  • Patent number: 6107648
    Abstract: A light emitting layer forming portion is formed of an AlGaInP-based compound semiconductor and having an n-type layer and a p-type layer to form a light emitting layer on the substrate. A large bandgap energy semiconductor layer is provided on a surface of the light emitting layer forming portion to constitute a window layer. A buffer layer is interposed between the light emitting layer forming portion and the large bandgap energy semiconductor layer to relieve lattice mismatch of between the light emitting layer forming portion and the large bandgap energy semiconductor layer. The interposition of this buffer layer provides a light emitting device that is high in light emitting efficiency and excellent in electrical characteristics without degrading the film property of the window layer.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: August 22, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Yukio Shakuda, Shunji Nakata, Yukio Matsumoto
  • Patent number: 6054716
    Abstract: A semiconductor light emitting device incorporates therein with (a) a light emitting portion formed by semiconductor overlying layers including a first conductivity layer and a second conductivity layer in order to a light emitting layer, and (b) a protecting element portion provided in electrical connection between said first conductivity type layer and said second conductivity type layer so that said light emitting portion is protected against at least a reverse voltage applied to said light emitting portion. The light emitting portion and the protecting element portion can be formed by separate chips or in one chip having the both. They are formed into a lamp-type or chip-type light emitting device. The incorporation of the protecting element increase the reverse-voltage resistance for a compound semiconductor, such as galium-itride or the like, that is less resistive to reverse voltages applied.
    Type: Grant
    Filed: January 6, 1998
    Date of Patent: April 25, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Masayuki Sonobe, Tsuyoshi Tsutsui, Shunji Nakata, Norikazu Itoh, Shinji Isokawa, Hidekazu Toda
  • Patent number: 5939735
    Abstract: A semiconductor light emitting device includes a substrate and semiconductor overlying layers formed on the substrate. A light emitting layer is formed in the semiconductor layer so as to emit light. The substrate is transmittable of the light emitted by the light emitting layer. A light reflecting layer is formed on a part of a back surface of the substrate. As a result, a semiconductor light emitting device is obtainable by easily dividing a wafer having thereon a light emitting film through recognizing, from a wafer back side, semiconductor layer chip pattern formed overlying the main surface of the wafer.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: August 17, 1999
    Assignee: Rohm Co., Ltd.
    Inventors: Tsuyoshi Tsutsui, Shunji Nakata, Yukio Shakuda, Masayuki Sonobe, Norikazu Itoh