A high current gain Si HBT with a hydrogenated micro-crystalline Si emitter

An npn Si HBT has been fabricated using hydrogenated micro-crystalline Si as a wide gap emitter with low resistivity, and has showed much higher common emitter current gain than a conventional homo-junction transistor. Measured common emitter current gains of the fabricated HBT´s having sub-emitter base sheet resistances of 14 kΩ/□ and 95Ω/□ are 1500 and 18 respectively. The maximum current gain is obtained at a collector current of as high as 3×10⁴A/cm².