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In part I, we extensively analyzed the results of the low-frequency noise characterization in advanced SiGe:C heterojunction bipolar transistors. In this paper, we demonstrate that base and collector noise spectral densities are partially correlated. The correlation is investigated by studying the coherence function at different bias conditions. The coherence reveals a frequency dependence at lower bias due to the presence of dominant generation–recombination mechanisms, whereas at higher bias, the coherence approaches unity. The bias dependence of the coherence is studied in several transistor geometries. In addition, a partially correlated base and collector 1/f noise model is proposed and implemented in HiCuM. Modeling results are in agreement with the measured data. [ABSTRACT FROM AUTHOR]

In this paper, we present extensive characterization of low-frequency noise in advanced silicon germanium heterojunction bipolar transistors. We demonstrate the extraction methodology of base and collector noise spectral densities for a wide range of transistor geometries. In addition to 1/ $f$ noise, generation–recombination (G–R) mechanisms are observed at low bias in the base current noise. Their existence is confirmed by Random Telegraph Signal (RTS) noise measurements. 1/ $f$ and G–R components are extracted from the base current noise spectra and their bias dependencies are studied. Finally, base current noise spectral densities measured at the same base current density in different geometries are compared to study the individual contribution of 1/ $f$ noise from the periphery as well as the intrinsic device. Part II of this paper will discuss the modeling aspects and noise correlation. [ABSTRACT FROM AUTHOR]