SiGe HBTs in 90nm BiCMOS technology demonstrating 300GHz/420GHz fT/fMAX through reduced Rb and Ccb parasitics

Scaling both the f
_T
and the f
_MAX
of SiGe HBTs is quite challenging due to the opposing physical device requirements for improving these figures of merit. In this paper, millisecond anneal techniques, low temperature silicide and low temperature contact processes are shown to be effective in reducing the base resistance. These processes when combined with a novel approach to address the collector-base capacitance are shown to produce high performance SiGe HBT devices which demonstrate operating frequencies of 300/420GHz f
_T
/f
_MAX
. This is the first report of 90nm SiGe BICMOS with an f
_MAX
exceeding 400GHz.