Very low cost graded SiGe base bipolar transistors for a high performance modular BiCMOS process

Abstract

We report a new super self-aligned graded SiGe base transistor that uses high energy implantation, rather than epitaxial growth, to form the sub-collector region. This new inexpensive process yields a device with f/sub T/ of 52 GHz and f/sub max/ of 70 GHz with the addition of only 4 lithography levels over our 0.25 /spl mu/m CMOS technology without any changes to the existing process steps. Also, we demonstrate 4:1 multiplexer and 1:4 demultiplexer circuits using this technology that show excellent performance at 10 Gbit/s.