Jonathan A. Pellish, Robert A. Reed, et al.
IEEE TNS
We report the experimental observation of a novel effect in SiGe heterojunction bipolar transistors (HBT's) with graded bases which results in a significant emitter-base bias dependence of the current gain. The nonideal collector current is caused by the interaction of the bias dependence of the emitter-base space-charge region width and the exponential dependence of the collector current on the germanium concentration at the edge of the space-charge region. The resulting current gain rolloff must be taken into account for accurate modeling of bipolar transistors with bandgap grading in the base. © 1993 IEEE
Jonathan A. Pellish, Robert A. Reed, et al.
IEEE TNS
Sophie Verdonckt-Vandebroek, Bernard S. Meyerson, et al.
IEEE Transactions on Electron Devices
Rajan Arora, Zachary E. Fleetwood, et al.
IEEE TNS
John D. Cressler
Microelectronic Engineering