X-band SiGe power HBT's

SiGe power heterojunction bipolar transistors were fabricated using the Northrop Grumman 6'' bipolar line, which features a polysilicon emitter and SiGe epitaxial base. The power cell utilizes a fishbone structure, with an active area of 500 /spl mu/m/sup 2/ and 1100 /spl mu/m emitter perimeter. Discrete cells were packaged for CW power testing in common base mode at 8 GHz. 267 mW of output power was achieved using two cells in parallel in class-A operation; at 120 mW output power, the gain is 8 db.