Abstract

A I W output power (2.8 W/mm) GaAs-based HBT with more than 56 % power added efficiency at 3 V operating bias for use in mobile communications is described. Device layout and technology are optimized to obtain high microwave performance with low thermal resistance and compact chip size. The fabricated sub-cell power HBTs with 3x30 urn2 emitter area yield a maximum current gain of 90 with fmax > 100 GHz. The power cell HBT, which has 12x3x30 um2 emitter area exhibits 3 W (8.4 W/mm) output power and 70 % power added efficiency at VCE=8 V while maintaining high performance at low supply bias of 3 V.