ABSTRACT
Crolles plant of STMicroelectronics, a few kilometers away. A joint development work was then initiated
between the two teams, with the objective to bring SiGe HBTs into manufacturing when the perform-
ance potential of silicon-only bipolar transistors would be fully exhausted [5]. This eventually happened
with the 25/40 GHz fT/fmax double-polysilicon self-aligned transistor embedded in the 0.35-mm BiCMOS
process. When it was internally demonstrated that much better performance, e.g., 50/70 GHz fT/fmax,
could be obtained at the same technology node using a low-complexity SiGe HBT architecture [6], SiGe
BiCMOS technology development at ST became a reality.
