THz InP/GaAsSb DHBTs with Record fAVG=800 GHz: Characterization to 330 GHz

We report the first independent characterization of THz "Emitter-Fin" double heterojunction bipolar transistors (DHBTs) up to 330 GHz, a considerable advancement in THz transistor characterization/metrology. An emitter area of (0.175 × 4.2) μm
²
yields f
T
/f
MAX
= 0.53/1.21 THz, corresponding to a record ${f_{{\text{AVG}}}} = \sqrt {{f_{\text{T}}}{f_{{\text{MAX}}}}} = 800\;{\text{GHz}}$ for bipolar transistors. The effect of emitter size and of f
MAX
extraction methods is characterized with respect to uncertainties. We also provide the first cryogenic characterization of a THz transistor with a record f
T
/f
MAX
= 0.57/1.46 THz at 50 K for a (0.2 × 9.2) μm
²
InP/GaAsSb DHBT. This is the highest f
MAX
ever achieved in a bipolar transistor.