Pulsed microwave characterization of an SiGe heterojunction bipolar transistor

This paper presents the first pulsed characterization of a silicon-germanium (SiGe) heterojunction bipolar transistor (HBT). Comparison is made of the SiGe HBT's performance to that of a Si bipolar junction transistor fabricated using the same mask set. Measurements made over a 400-/spl mu/s pulse show how device self-heating dramatically affects the microwave-frequency response of the devices. Using pulse-profiled S-parameters to find the intrinsic base resistance r/sub /spl pi// and base-collector capacitance C/sub jc/, plots reveal how these two elements significantly vary over the length of the pulse. The results emphasize the need for accurate characterization of microwave Si-based devices in pulsed applications.