Characterization of insulated-gate versus schottky-gate InAs/AlSb HEMTs

Fabrication and characterization of 225 nm gate-length InAs/AlSb HEMTs with excellent RF performance are reported. We show the importance of an insulating layer between the gate and the semiconductor to improve g
_m
, f
_T
and f
_max
, and most important from a noise perspective, the gate-leakage current I
_G
. By using an insulated-gate, I
_G
was reduced by two orders of magnitude. The insulated-gate HEMTs exhibited extrinsic f
_T
and f
_max
of 155 GHz and 115 GHz, respectively, at V
_DS
=0.5 V.