A novel simulation assisted investigation was used to obtain the optimum collector design of a 200 GHz silicon-germanium (SiGe) hetero junction bipolar transistor (HBT) for manufacturing. Technology computer aided design (TCAD) tools were applied in a stepwise methodology to explore the large and complex design space and to fully understand the tradeoffs between all relevant HBT performance parameters. (C) 2003 Elsevier B.V. All rights reserved.