Improved current gain in bipolar transistor with bandgap narrowing in base

Bandgap narrowing in a base was utilised to improve the current gain of the Si bipolar transistor. It enhances the injection of emitter current into the base. A transistor the authors fabricated with a base doping concentration of 2*10¹⁹/cm³ showed a bandgap narrowing of about 90 meV that enables about 25 times more collector current to flow than where there is now narrowing. Bandgap narrowing enables the fabrication of a transistor with a very thin base, enough current gain and moderate base resistance.