Vertical scaling of planarized InP/InGaAs heterojunction bipolar transistors with f/sub T/>350 GHz and f/sub max/>500 GHz

A dielectric planarization process was developed which enabled aggressive scaling of both emitter area and base-collector capacitance. Transistors were fabricated with emitters as small as 0.14 /spl mu/m, with the fastest HBTs using 0.4-/spl mu/m emitters.