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%0 Thesis %A Kamrani, Mohammad Hamed %T Semi-classical simulation of state-of-the-art toward-terahertz silicon-germanium heterojunction bipolar transistors %I RWTH Aachen University %V Dissertation %C Aachen %M RWTH-2017-08275 %P 1 Online-Ressource (xii,92 Seiten) : Illustrationen, Diagramme %D 2017 %Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University %Z Dissertation, RWTH Aachen University, 2017 %X This work presents a microscopic simulation and modeling framework for the state-of-the-art toward-terahertz silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). To this goal, a stationary deterministic solver based on a spherical harmonics expansion of the coupled system of Boltzmann transport equations for electrons, holes, and phonons has been developed. The simulation results of this in-house deterministic solver, which includes full band structure and high-field effects, are verified against experimental data. To investigate non-equilibrium effects for the carrier-phonon system, the impact of hot longitudinal optical phonons on steady state carrier transport is discussed. Furthermore, the self-consistent and deterministic solution of the coupled set of equations allows to extract the junction temperature by making use of a method based on the simulated DC characteristics. The resultant junction temperature is compared to the value obtained from the temperature profile within the nanoscale device. Good agreement is obtained for the average temperature in the base-emitter junction verifying the analytical approach used to extract the thermal resistance of the device by experiments. In order to obtain a new insight into the underlying mechanisms of hot-carrier degradation in bipolar transistors, a physics-based model based on the distribution functions of both hot electrons and hot holes is introduced. The full-band transport model provides the energy distribution functions of the charge carriers interacting with the passivated Si-H bonds along the oxide interface. The simulation results assert the dominant role of hot holes along the emitter-base spacer oxide interface in the long-term degradation of an npn SiGe HBT under low and high-current conditions at the border of the safe operating area. The interface trap density, which is calculated by incorporating a reaction-limited model with dispersive reaction rates, explains the time dependence of the interface trap density and the resulting forward-mode leakage base current for different stress bias conditions. %F PUB:(DE-HGF)11 %9 Dissertation / PhD Thesis %R 10.18154/RWTH-2017-08275 %U https://publications.rwth-aachen.de/record/699408