Comprehensive studies of InGaP/GaAs heterojunction bipolar transistors with different thickness of setback layers

The performances of InGaP/GaAs heterostructure bipolar transistors (HBTs) with different thickness of setback layers are theoretically studied. The appropriate thickness of the setback layer is an important factor in high-speed HBTs. In this work, it is found that the HBT device with a 60-90 Å setback layer has better DC and RF characteristics due to the absence of potential spike and reduced transit time. In addition, the studied devices with appropriate setback layer thickness have lower offset voltage, reverse saturation voltage, and base and collector current ideality factor.