Self-consistent simulations of transient heating effects in electrical devices using the finite integration technique

A newly developed method for coupled electromagnetic and thermal simulations of electrical devices with heat losses is presented. The method is based on the finite integration technique (FIT). Temperature dependent device-material properties, as well as radiant and convective boundary conditions are accommodated in the model. The performance of the method is demonstrated in the simulation of a high precision eddy current welding application and in the calculation of the transient response of a multifinger AlGaAs/GaAs heterojunction bipolar power transistor (HBT). In the latter, a discussion of the effects of thermal shunting in the self-heating process is given.