Development of an Electrothermal Simulation Tool for Integrated Circuits
thesisposted on 23.05.2021, 18:28 by Sara Sharifian Attar
The goal of this research was to develop a capability for the electrothermal modeling of electronic circuits. The objective of the thermal modeling process was to create a model that represents the thermal behavior of the physical system. The project focuses on electrothermal analysis at devices and chip level. A novel method to perform electrothermal analysis of integrated circuits based on the relaxation approach is proposed in this research. An interface program couples a circuit simulator and a thermal simulator. The developed simulator is capable of performing both steady state and transient analaysis at devices and chip level. The proposed method was applied to perform electrothermal analysis of Silicon Bipolar Junction Transistor (BJT) to predict the temperature distribution and the device performance in a circuit. Thermal nonlinearity due to temperature-dependent material parameters in the context of thermal modeling of the device and circuit has also been considered. The DC characteristics of the device were investigated. The obtained results indicate that the operating point of the device varies while the device reaches its junction temperature. The accuracy of the electrothermal simulator has been evaluated for steady state analysis. The experimental results of a BJT amplifier were compared to the simulator results of the similar circuit. The electrothermal simulation results of BJT amplifier circuit indicate a good agreement with the available experimental results in terms of power dissipation, collector current and base-emitter voltage. The performance of the electrothermal simulator has been evaluated for tansient analysis. A current mirror circuit using Si NPN BJTs was simulated. According to the electrical simulator, the output current follows the reference current immediately. Nonetheless, the electrothermal simulator results depict that the load current has delay to reach a constant value which is not the same as the reference current, due to the influence of thermal coupling and self heating. The obtained results are in agreement with the available results in literature.