Footprint design optimization in SiGe BiCMOS SOI technology

Footprint design in SiGe BiCMOS SOI technology is described in this paper to improve device performance matrix. The safe operating area (SOA) for a SiGe hetero-junction bipolar transistor (HBT) fabricated on silicon on insulator (SOI) is significantly improved as the footprint area increases. The Early voltage for SiGe HBT on SOI at medium-high bias range also increases substantially with footprint area increase. Peak f_T and noise figure improves slightly with footprint, and peak f_MAX improves slightly then decreases significantly at very large footprint area. A generic tube-area-limited thermal resistance model for BiCMOS devices on SOI is also proposed.