Low Frequency Noise Study of X-ray Irradiated Si/SiGe:C BiCMOS Technology Bipolar Transistors

The DC and low-frequency noise (LFN) study of pre-rad and post-rad X-ray irradiation of SiGe:C HBTs based on a 55 nm BiCMOS technology is presented. HBTs are developed with three different levels of doping in the collector region for applications requiring high speed (HS), medium voltage (MV), and high voltage (HV) operations. This work presents excess DC base current, the 1/f noise model using the SPICE modeling and provides the descriptive behavior of G-R noise components for three different HBTs (HS, MV, and HV) before and after irradiation (as a function of the total ionizing dose (TID)). By comparing the DC and low- frequency noise (LFN) results with respect to TID, the discussion deals with the location of the noise sources and related traps. Particularly, it underlines the role of the SiO2/Si E-B spacer interface.