We report the process flow and technological features of Infineons' 75 GHz bipolar technology, which is characterized by a double-poly self-aligned transistor structure and a SiGe base, grown by selective epitaxy. The dependence of the epitaxial deposition on growth conditions and the influence of layout on the growth process is discussed, especially for different kinds of reticles: bipolar-ICs, BICMOS-ICs and discrete semiconductors. Finally, our monitoring concept for the control of the selective SiGe epitaxy is presented and compared with alternative methods of process control.