ABSTRACT
The history of SiGe BiCMOS technology development in the ‘‘French silicon valley’’ goes back to the
early 1990s [1], when a team of materials researchers at France Telecom CNET Laboratories near
Grenoble started investigations in the Si/SiGe system using rapid thermal chemical vapor deposition
(RTCVD). Application of this work to the development of heterojunction bipolar transistors (HBTs)
soon became a major research theme for the local bipolar device group [2-4]. At the same time, the
development of a 0.5-mm single-polysilicon BiCMOS technology was going on in the new 200mm
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 25/40GHz 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., 50/70GHz fT/fmax,
could be obtained at the same technology node using a low-complexity SiGe HBTarchitecture [6], SiGe
BiCMOS technology development at ST became a reality.
