35-nm Zigzag T-Gate $\hbox{In}_{0.52}\hbox{Al}_{0.48} \hbox{As/In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ Metamorphic GaAs HEMTs With an Ultrahigh $f_{\max}$ of 520 GHz

Metamorphic GaAs high electron mobility transistors (mHEMTs) with the highest-
f

_max
reported to date are presented here. The 35-nm zigzag T-gate In
_0.52
Al
_0.48
As/In
_0.53
Ga
_0.47
As metamorphic GaAs HEMTs show
f

_max
of 520 GHz,
f

_T
of 440 GHz, and maximum transconductance (
g

_m
) of 1100 mS/mm at a drain current of 333 mA/mm. The combinations of
f

_max
and
f

_T
are the highest data yet reported for mHEMTs. These devices are promising candidates for aggressively scaled sub-35-nm T-gate mHEMTs.