Patents by Inventor Tosifumi Oohata

Tosifumi 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).

  • Patent number: 5343052
    Abstract: A lateral insulated-gate bipolar transistor has a drift region having therein a base layer and a collector layer. An emitter layer is formed in the base layer. A gate electrode structure, comprising a control electrode and gate insulating layer, contacts the base layer, and also contacts the drift layer and the emitter layer. An emitter electrode contacts the emitter layer, and also the base layer, and a collector electrode contacts the collector layer. The emitter and collector electrodes are elongate and the ratio of their resistances per unit length is in the range of 0.5 to 2.0. This reduces the possibility of a localized high current density along the electrodes, thereby reducing the risk of latch-up due to parasitic thyristors. The collector and emitter electrodes may be of the same width and thickness, or of different widths and thicknesses, or may each have an auxiliary part (for example, in a multi-layer wiring arrangement), so that their resistances per unit length are in the desired range.
    Type: Grant
    Filed: July 24, 1992
    Date of Patent: August 30, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Tosifumi Oohata, Mutsuhiro Mori, Naoki Sakurai