This work presents a comprehensive noise
characterization of advanced Si/SiGe:C Heterojunction Bipolar
Transistors (HBTs) associated with a 0.13 μm BiCMOS
technology. The study was carried out over a broad temperature
spectrum (293 to 4 K) and a frequency range (10 kHz to 12
GHz). The noise characteristics of SiGe HBTs are inspected as
functions of bias, frequency, and temperature; this is, to the
best of our knowledge, the first study to cover these broad
temperature and frequency ranges simultaneously. Through
meticulous examination, we identify a substantial increase in the
flicker noise coefficient KF , by a factor of 5.5 from 5.52 × 10−10
at 293 K to 3 × 10−9 at 4K. Furthermore, there is an increase in
corner frequency for a constant collector current density Jc when
the temperature is reduced to 4 K. Furthermore, to consider the
enhancement of the high-frequency parameters (fT and fmax)
reaching 500 GHz, related to this technology, we examined the
ratio fc/fT , which connects the Low Frequency Noise (LFN)
and the transistor speed. At 4 K, this ratio shows a minimum
of 2 ×10−9 at 2mA/μm2, which outperforms other advanced
CMOS nodes. By addressing the modeling of HBTs that are the
core active components of circuits used with quantum devices
and sensors operating at deep cryogenic temperatures, we believe
that this study will be beneficial to designers of classical-quantum
interfaces in several emerging applications.