A careful prediction of the carrier mobility and impact-ionization generation is essential for the design of devices working in high-current/voltage conditions, where self-heating is relevant. Recently, some of the authors presented new physically-based models for both mobility and impact ionization, which have been validated up to very high operating temperatures. Such work is based on theoretical analyses, that confirmed both the numerical and experimental findings about the field and temperature dependencies. The availability of such models provides the background for the realization of predictive simulation tools for power and electrostatic-discharge protection devices