Modeling of broadband noise in complementary (npn + pnp) SiGe HBTs

We present the first comprehensive investigation of broadband noise in a complementary (npn + pnp) SiGe (C-SiGe) HBT BiCMOS technology. A base-transit time based simple noise model with its origins in linear noisy two-port theory is presented, which takes into account the fundamental base and collector shot noise in a bipolar transistor, and their cross-correlation. The minimum noise figure of the npn and the pnp SiGe HBT in this technology at 2.0 GHz is measured to be 1.0 dB and 1.4 dB, respectively. This noise model is compared with the conventional SPICE noise model and the measured differences in the noise behavior of the npn and pnp SiGe HBTs are analyzed.