InAs/In1-xGaxAs Composite Channel High Electron Mobility Transistors for High Speed Applications

80-nm InAs channel HEMTs with different lattice matched sub-channels, In
_0.53
Ga
_0.47
As and In
_0.7
Ga
_0.3
As, have been fabricated. The device with InAs/In
_0.7
Ga
_0.3
As composite channel exhibits high drain current density (1101 mA/mm), and high transconductance (1605 mS/mm) at drain bias V
_DS
= 0.8 V. The high current gain cutoff frequency (f
_t
) of 360 GHz and maximum oscillation frequency (f
_max
) of 380 GHz of the device with InAs/In
_0.7
Ga
_0.3
As were obtained at V
_DS
= 0.7 V in comparison to the InAs/In
_0.53
Ga
_0.47
As channel HEMTs with f
_t
= 310 and f
_max
= 330 GHz. This is due to the high electron mobility and electron confinement in the InAs/In
_0.7
Ga
_0.3
As channel. In addition, a low gate delay time 0.84 psec was obtained at V
_DS
= 0.5 V. The excellent performance of the InAs channel HEMTs demonstrated in this study shows great potential for high speed and very low power logic applications with the optimal design of In
_0.7
Ga
_0.3
As/InAs/In
_0.7
Ga
_0.3
As composite channel.