An investigation of low-frequency noise in complementary SiGe HBTs on SOI

Low-frequency noise in complementary SiGe HBTs on SOI is investigated. S_ib is extracted using a custom measurement setup, and the corresponding K factors are compared across multiple SiGe technology platforms for better understanding of SiGe evolutionary trends. We find that low-frequency noise has generally decreased with scaling for both npn and pnp SiGe HBTs, despite the low thermal cycles that aggressive scaling techniques utilized. In general, pnp SiGe HBTs have higher noise than npn´s, and this is true for Si BJTs as well as SiGe HBTs. The SiGe HBTs on SOI from an early C-SiGe platform presented here fit these trends, demonstrating their maturity and competitiveness. Low input-impedance noise measurement were also measured and analyzed in these SiGe HBTs, using a common-collector and a common-base configuration. We find that noise term S_ic can be significant at high injection levels.