Performance improvement of InxGa1−xAs Tunnel FETs with Quantum Well and EOT scaling

In
_0.53
Ga
_0.47
As/In
_x
Ga
_1-x
As/In
_0.53
Ga
_0.47
As Quantum Well (QW) structure Tunnel FETs (TFETs) has been proposed and demonstrated. The systematic QW In content and thickness dependence on the TFET performance was quantitatively examined. The QW TFETs can significantly enhance the tunneling probability and resulting on-current (I
_on
) by lower bandgap (E
_g
) of the higher In content InGaAs than bulk In
_x
Ga
_1-x
As TFETs, while the increase in the off current (I
_off
) can be suppressed by source junction formation in low In content In
_0.53
Ga
_0.47
As regions. The minimum sub-threshold swing (S.S.
_min
) of 62 mV/dec was obtained at V
_D
=150mV in the In
_0.53
Ga
_0.47
As/In
_x
Ga
_1-x
As (3nm)/In
_0.53
Ga
_0.47
As QW structure. Also, the highest I
_on
of 56μA/μm at V
_D
=1V among the fabricated InGaAs QW TFETs was obtained by In
_0.53
Ga
_0.47
As/InAs(5 nm)/In
_0.53
Ga
_0.47
As QW structure. We have also realized EOT-scaled bulk In
_0.53
Ga
_0.47
As TFETs with 1.7nm-CET HfO
₂
(2.7nm)/Al
₂
O
₃
(0.3nm) gate stacks, exhibiting S.S
_min
of 57 mV/dec at V
_D
=100 mV.