An InGaAs/InP DHBT With Simultaneous $\text{f}_{\boldsymbol \tau }/\text{f}_{\text {max}}~404/901$ GHz and 4.3 V Breakdown Voltage

We report an InP/InGaAs/InP double heterojunction bipolar transistor fabricated in a triple-mesa structure, exhibiting simultaneous 404 GHz f
_τ
and 901 GHz f
_max
. The emitter and base contacts were defined by electron beam lithography with better than 10 nm resolution and smaller than 20 nm alignment error. The base-collector junction has been passivated by depositing a SiN
_x
layer prior to benzocyclobutene planarization, improving the open-base breakdown voltage BV
_CEO
from 3.7 to 4.3 V.