Fully coupled electrothermal mixed-mode device simulation of SiGeHBT circuits

It is well known that for the design and simulation of state-of-the-art cir cuits thermal effects like self-heating and coupling between individual dev ices must be taken into account. As compact models for modern or experiment al devices are not readily available, a mixed-mode device simulator capable of thermal simulation is a valuable source of information. Considering sel f-heating and coupling effects results in a very complex equation system wh ich can only be solved using sophisticated techniques. We present a fully c oupled electrothermal mixed-mode simulation of an SiGe HBT circuit using th e design of the mu A709 operational amplifier By investigating the influenc e of self-heating effects on the device behavior we demonstrate that the co nsideration of a simple power dissipation model instead of the lattice heat flow equation is a very good approximation of the more computation time co nsuming solution of the lattice heat flow equation.