Commercial Viability of a Merged HBT-FET (BiFET) Technology for GaAs Power Amplifiers

This paper covers the history and recent developments of GaAs BiFETs in commercial high volume GaAs HBT manufacturing environment. Further more, the paper also goes into “merged/stacked” FET-HBT integration schemes and their impacts on cost, yield and cycle time. Various circuit applications such as stage bypassing, attenuators, advanced bias circuit controls etc., that are realized in both BiFET approaches are also reviewed to show the commercial success of BiFET process technology. The challenges in using stacked FET-HBT geometry for an integrated transmit/receive switch and an alternative approach of utilizing advanced multi-chip module (MCM) techniques to deliver the same level of functionality in the smallest possible form-factor are examined with an emphasis on functional test yield and fabrication process yield.