Submicron self-aligned HBT's by selective emitter regrowth

Fabrication of fully self-aligned heterojunction bipolar transistors (HBTs) by selective emitter regrowth is described. Scaled devices with emitter dimensions as small as 0.4×7 μm
²
demonstrate current gain up to 29, with successful suppression of surface recombination effects. The RF characteristics of a 1.4×11 μm
²
device exhibited f
_T
and f
_max
of 75 and 46 GHz, respectively, and is limited by the refractory base metallization. This technology is promising for scaled HBT applications where high-speed and low-power dissipation are critical.