A 210-GHz fT SiGe HBT with a non-self-aligned structure

A record 210-GHz f
_T
SiGe heterojunction bipolar transistor at a collector current density of 6-9 mA/μm
²
is fabricated with a new nonself-aligned (NSA) structure based on 0.18 μm technology. This NSA structure has a low-complexity emitter and extrinsic base process which reduces overall thermal cycle and minimizes transient enhanced diffusion. A low-power performance has been achieved which requires only 1 mA collector current to reach 200-GHz f
_T
. The performance is a result of narrow base width and reduced parasitics in the device. Detailed comparison is made to a 120-GHz self-aligned production device.