Simple CAD technique to develop high-frequency transistors

The emitter and base impurity concentration profiles and the epitaxial thickness of the collector of n-p-n microwave transistors have been optimized for f/SUB max/ by a simple computer-aided design technique. The optimized profile was synthesized and led to devices with f/SUB max/ between 15 and 18 GHz when fabricated with a mask with 1.5-μ emitter widths. The details of the optimization procedure, the synthesis procedure and the r.f. results of fabricated devices are described.