(Invited) Electro-Thermal Characterization of SiGe HBT PA-Cells

The European FP7 DOTSEVEN project is motivated by the increasing interest in utilizing the mm-wave frequency spectrum within the so-called THz gap (which ranges from 0.3 to 30 THz) for a wide variety of applications. In order to design and demonstrate working integrated mm- and sub-mm-wave circuits, the DOTSEVEN consortium aims the realization of SiGeC Heterojunction Bipolar Transistors (HBTs) operating at a maximum frequency up to 0.7 THz (i.e. 700 GHz) at room temperature. One associated main objective of the DOTSEVEN project is the evaluation, understanding, and modeling of the relevant physical effects occurring in such high-speed devices and circuits. The higher the speed of advanced HBTs is the higher are their current densities and internal electric fields. This leads to increased self-heating and potential thermal instabilities. Their detailed impact on device characteristics and parameter extraction are investigated from a theoretical point of view with 3D thermal simulations, and from an experimental point of view with pulsed DC and AC measurements. Furthermore the impact of deep trenches on heat dissipation is analyzed as well as the thermal coupling with adjacent emitter fingers and pcells.