Patent ID: 6114745
Filing Date: 2000-09-05
Classification: H01L

Abstract:
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; andan 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.