High-gain and oscillatory transconductance by InGaAs/InAlAs multiple-quantum-well emitter bipolar transistor
✍ Scribed by W.-S. Lour
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 214 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
We report an InGaAs/InAlAs multiple-quantum-well (MQW) emitter bipolar transistor prepared by molecular beam epitaxy. There are three distinct operating regimes to be observed in the studied structure. At small input base currents, low field band-type conduction provides the output current. The device exhibits a small gain and works as a normal transistor. With further increase in the base current, the high field starts appearing in the MQW superlattice. We observe that both the output current and transconductance exhibit an oscillatory behaviour in terms of sequential resonant-tunnelling through an expanding high field MQW domain. Beyond the condition of expansion of high field domain, the electron current increases rapidly by tunnelling through the triangular barrier and emitting over the base layer. The MQW superlattice now works as a barrier to hole minority carriers within this region. We obtain a common-emitter current gain as high as 240 with a small offset voltage of about 80 mV.