The DOTFIVE project partner from the University of Wuppertal has used at IHP an HBT-only evaluation version of a BiCMOS technology for benchmark circuit fabrication. Results of this preparation are presented at the ISSCC conference 2010.
In contrast to IHP’s 0.13m BiCMOS process (details see BCTM 2009), the following steps, affecting the HBT performance, were altered: The profile of the SiGe:C base layer was changed resulting in a lower base-sheet resistance while the collector current density was maintained approximately. The temperature of the final spike anneal was reduced. Furthermore, the wafers exhibit a 45° rotated substrate orientation, an enhanced sub-collector and a reduced salicide sheet resistance. The transistors achieve at VBE=0.7V a current gain of about 500 and demonstrate an open-base collector-emitter breakdown-voltage BVCEO of 1.7 V. Compared with the 0.13µm BiCMOS reference HBT, the peak fT /fmax values could be increased from 240 GHz / 330 GHz to approximately 250GHz/380GHz in this modified technology (see Fig. 3).