Characterization, modeling and comparison of 1/f noise in Si/SiGe:C HBTs issued from three advanced BiCMOS technologies

The main objective of the development of new BiCMOS technologies is to enhance the high frequency performances of the devices. Nevertheless, Low Frequency Noise (LFN) analysis, in particular the 1/f noise, is a very sensitive tool to evaluate a technology. In this work we present a complete characterization and modeling of the 1/f noise in Si/SiGe:C HBTs issued from three BiCMOS technologies (130 nm, shrinked 130 nm and 55 nm). The measured base current spectral density SIB, in the HBTs issued from a 130 nm BiCMOS technology, presented a typical behavior of 1/f noise. The extracted SPICE figure of merit Kb has an excellent value of 1.4 10−10 μm2. For HBTs issued from the two other technologies (shrinked 130 nm and recent under development 55 nm) the low frequency noise spectra are often disrupted by the presence of more or less pronounced Lorentzian shape leading to noise dispersion. In HBTs where a typical behavior was observed, the 1/f noise level was found to be proportional to the square of IB, and inversely proportional to the emitter area Ae. The extracted Kb value was equal to 6 10−10 for the shrinked 130 nm technology and approximately 10−9 μ2 for the 55 nm technology. In order to take into account the HF performances, we have also studied the ratio fc/ft. This figure of merit combines LF Noise and HF characteristics.