Modeling high-frequency noise in SiGe HBTs using delayed minority charge

Abstract

Based on delayed minority charge high frequency correlated noise in silicon germanium heterojunction bipolar transistor is modeled. Following system theory, the formulated model equations are accurately implemented in Verilog-A using four extra nodes. Results show excellent agreement with numerically simulated data. Simplified model versions are also implemented and tested. Relation between highfrequency correlated noise and non-quasi-static effect is identified through delayed minority charge.

Graded Applications of NQS Theory for Modeling Correlated Noise in SiGe HBTs

“…it and ibei are the quasi-static transfer current and internal base current, respectively. Tf, kc, and alqf (3,4,5) correspond to τ f , k c , and A Q (3,4,5) , respectively. (14) can further be simplified by taking: 1) A Q = 0 in all the denominator terms; 2) A Q5 = 0; and 3) A Q4 = 0, which convert (14) into…”

“…However, the simplified model of [2] does not use the same set of model parameters used in the underlying NQS model. In the last few years, serious efforts have been made to obtain a correlated noise model that uses the same NQS model parameters [5], [6]. The noise model in [6] uses a purely imaginary correlated noise-PSD, which may be formulated from the partition charge based NQS model of [7] or from the first order term in the Te-Winkel's NQS model for transadmittance parameter (y 21 = g m0 exp(− j ωτ d )) [8], whereas the underlying NQS model in [6] uses the second order Bessel filter function of Weil-McNamee [9].…”

Efficient models for non-quasi-static effects and correlated noise in SiGe HBTs

“…Based on this proposed PCB NQS model, the correlated noise model in [7] is modified and presented in this subsection. The new noise power spectral densities (PSDs) of a 1-D bipolar transistor in common-emitter (CE) configuration read, The implementation of (5) involves a transformation of the corresponding correlated noise sources, i nb and i nc into three uncorrelated noise sources, i D1 , t 12 i D2 (at the input) and i D2 (at the output) using system theory [7] [9].…”

“…The microscopic noise model in [12] ((2) in [7]) is used over the device simulation results to generate the reference noise PSD data and the reference noise parameters are obtained following [13]. Figs.…”

“…The X ph is modeled by analytically treating the output of an additional CR subcircuit as reported in [6]. Based on the NQS model in [5], a correlated noise model is developed and reported in [7], the exact implementation of which requires four additional nodes.…”