BOTH compact modeling and physics-based electro-thermal models [346,92] have their individual benefits for each application. In order to obtain sufficiently accurate simulation results in reasonable time, physics-based models have to be used at a certain level of abstraction. In contrast, if speed is more important, compact models often provide a good alternative. However, to obtain accurate and reasonably fast simulation results, an appropriate combination of compact models and fundamental physical equations has to be found for each class of simulation problem. There is a very large number of different simulation tools available, which are able to accurately calculate certain effects in different levels of details. But there are also some simulators and frameworks that provide a wide range of different basic models as well as compact models to cover a wide range for industrial demands. For very specific investigations of highly sophisticated devices, however, the standardized models inherently are often not sufficient enough and physic-based models are thus indispensable. Consequently, the user has to decide the level of detail for each simulation, in order to choose the appropriate models in the simulation tools to obtain reasonable results for the current simulation.