Fabrication and characterization of antimonide-based composite-channel InAs/AlGaSb HFETs using high-k gate insulators

We report on the fabrication and characterization of antimonide-based composite-channel InAs/AlGaSb HFETs. Antimonide-based compound semiconductors such as those of InAs combined with Al
_x
Ga
_1-x
Sb are candidates for high-speed and low-power digital applications. InAs/AlGaSb HFETs utilizing high-k (HfO
₂
) gate insulator were fabricated using a Pd/Au ohmic metallization. The HFETs exhibited transconductance, g
_m
and maximum drain current density, I
_d
of 270 mS/mm, and 360mA/mm. Furthermore, InAs HFETs using the Ga
₂
O
₃
/HfO
₂
stacks as a gate insulator and shows a g
_m
of 318 mS/mm, that is, the transconductance was improved by using a Ga
₂
O
₃
dielectric.