Analytical modeling and numerical simulations of the thermal behavior of bipolar transistors

The thermal behavior of various bipolar transistor categories, namely, trench-isolated (1) SOI BJTs, (2) BJTs fabricated on silicon substrates, and (3) SiGe HBTs, is thorougly analyzed. Detailed 3-D numerical simulations are employed to provide a deep understanding of the thermal process in all the structures. Based on the numerical analysis, novel highly-effective analytical thermal models are conceived and developed for a fully predictive detection of the temperature field corresponding to an assigned dissipated power. All the models make use of simplified representations of the domains under analysis as well as 3rd-kind boundary conditions to describe the heat propagation through the insulating layers.