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Bipolar transistor having high emitter efficiency

  • US 6,114,745 A
  • Filed: 07/30/1999
  • Issued: 09/05/2000
  • Est. Priority Date: 07/30/1999
  • Status: Expired due to Term
First Claim
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1. A bipolar transistor with high emitter efficiency in an integrated circuit semiconductor device, the transistor comprising;

  • a substrate;

    a collector region of a first conductivity type supported by the substrate;

    a base region of a second conductivity type supported above the substrate in a PN-junction-forming relationship with the collector region; and

    an emitter supported above the substrate in a PN-junction-forming relationship with the base region on a face of the base region opposite from the collector region;

    wherein the emitter includes a monocrystalline semiconductor region of the first conductivity type at the base-emitter PN-junction, a polycrystalline semiconductor layer of the first conductivity type spaced from the monocrystalline emitter region, and a tunneling barrier layer interposed between and in contact with the monocrystalline region and polycrystalline layer, the tunneling barrier layer having a thickness of about 100 to 200 angstroms and an energy band gap in the range of about 1.8 to 3.5 eV.

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