[paper] Modeling of Nonlinear Thermal Effects in BJT

Analytical Modeling and Numerical Simulation of Nonlinear Thermal Effects in Bipolar Transistors

D'Alessandro, Vincenzo, Ciro Scognamillo, Antonio Pio Catalano, Markus Müller, Michael Schröter, Peter J. Zampardi, and Lorenzo Codecasa

28th THERMINIC (2022), pp. 1-7. IEEE, 2022

DOI: 10.1109/THERMINIC57263.2022.9950637

Abstract: This paper addresses the problem of modeling nonlinear thermal effects in bipolar transistors under static conditions. The impact of these effects on the thermal resistance is explained in detail and analytically modeled using the assumption of a single-semiconductor device. FEM thermal simulations of high-frequency transistors are performed to evaluate the accuracy of the single-semiconductor theory and of the thermal resistance formulations currently employed in the most popular compact transistor models. It is shown that these models do not correctly account for nonlinear thermal effects. Various implementations of the more accurate single-semiconductor theory are then suggested for their future releases.

FIG: (a) geometry of the InGaP/GaAs HBT under test and 

(b) corresponding mesh

Acknowledgments: The authors wish to thank Dr. Klaus Aufinger for providing the technology/geometry details of the Si/SiGe HBT analyzed in the paper.

Markus Muller and Michael Schroter acknowledge partial financial support from the Deutsche Forschungsgemeinschaft (project SCHR695/21).

The funding for the Ph.D. activity of Ciro Scognamillo was generously donated by the Rinaldi family in the memory of Niccolo Rinaldi, a bright Professor and Researcher of University of Naples Federico II, prematurely passed away in 2018.