InAlAs/InGaAs heterojunction bipolar transistors (HBT’s) grown by molecular beam epitaxy are fabricated. A cutoff frequency (fT) of 52 GHz is achieved in the HBT’s with a base thickness of 1000 Å. A decrease in fT under a high collector current density condition is observed. This is attributed both to the base widening and base-collector capacitance increase caused by the electron space charge in the collector depletion layer.
- Cutoff frequency
- Heterojunction bipolar transistor
- Hole concentration compensation
- Molecular beam epitaxy
ASJC Scopus subject areas
- Physics and Astronomy(all)