M. Rossberg et al., SIMULATION OF INFLUENCE OF UNDOPED SPACER LAYERS IN SI SIGE-HBTS ON TRANSIT FREQUENCY/, Electronics Letters, 29(1), 1993, pp. 85-87
By means of numerical simulation the influence of undoped (i-) layers
at the heterojunctions of Si/SiGe-HBTs on the transistor characteristi
cs is shown. An increased transit frequency should be obtained by inse
rting an i-Si layer between the emitter and base and an i-SiGe layer b
etween the base and collector regions of the HBT.