A 30-Gbit/s demultiplexer IC based on Si/SiGe emitter base heterojunction bipolar transistors

A 30-Gbit/s demultiplexer IC has been fabricated and tested using an improved double mesa Si/SiGe heterojunction bipolar transistor process. This is-to our knowledge-the highest ever reported bit rate for "real" (as opposed to drift transistor) Si/SiGe HBT circuits. The result was mainly reached by scaling down the transistor sizes to reduce parasitics. The minimum emitter mesa width was 1 /spl mu/m.