Impact of Forming Gas Annealing on the Performance of Surface-Channel $\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ MOSFETs With an ALD $\hbox{Al}_{2}\hbox{O}_{3}$ Gate Dielectric

We investigated the effect of forming gas (5% H
₂
/95% N
₂
) annealing on surface-channel In
_0.53
Ga
_0.47
As MOSFETs with atomic-layer-deposited Al
₂
O
₃
as the gate dielectric. We found that a forming gas anneal (FGA) at 300°C for 30 min was efficient at removing or passivating positive fixed charges in Al
₂
O
₃
, resulting in a shift of the threshold voltage from -0.63 to 0.43 V and in an increase in the
I
_on
/
I
_off
ratio of three orders of magnitude. Following FGA, the MOSFETs exhibited a subthreshold swing of 150 mV/dec, and the peak transconductance, drive current, and peak effective mobility increased by 29%, 25%, and 15%, respectively. FGA significantly improved the source- or drain-to-substrate junction isolation, with a reduction of two orders of magnitude in the reverse bias leakage exhibited by the Si-implanted In
_0.53
Ga
_0.47
As n
⁺
/p junctions, which is consistent with passivation of midgap defects in In
_0.53
Ga
_0.47
As by the FGA process.