Electrothermal simulation of SiGe HBTs and investigation of experimental extraction methods for junction temperature

We present an electrothermal simulator for lattice temperature calculation in Silicon-Germanium (SiGe) hetero-junction bipolar transistors (HBTs) by including self-heating in Boltzmann transport equations (BTEs) of electrons and holes, where the BTEs are solved by deterministic methods based on a spherical harmonics expansion. Using the I-V characteristics of the device with taking self-heating into account, junction temperature is calculated with the thermal resistance extraction method, where the extracted temperature corresponds exactly to the average temperature increase over the base-emitter junction. Finally, the influence of both electrothermal simulation with phonon temperature distributions and isothermal simulation with homogeneous junction temperature on the I-V characteristics of HBT is investigated.