Vertical profile design and transit time analysis of nano-scale SiGe HBTs for Terahertz f/sub T/

We present a nano-scale SiGe HBT design for above Terahertz f/sub T/. The graded profile is shown to produce better performance than the box profile with the same total Ge (and hence film stability). A 2000 GHz/spl middot/V f/sub T//spl times/BV/sub CEO/ is shown in simulations using the graded Ge profile.