Impact of Forming Gas Annealing on the Performance of Surface-Channel In0.53Ga0.47As MOSFETs With an ALD Al2O3 Gate Dielectric

We investigated the effect of forming gas (5% H-2/95% N-2) annealing on surface-channel In0.53Ga0.47 As MOSFETs with atomic-layer-deposited Al2O3 as the gate dielectric. We found that a forming gas anneal (FGA) at 300 degrees C for 30 min was efficient at removing or passivating positive fixed charges in Al2O3, resulting in a shift of the threshold voltage from -0.63 to 0.43 V and in an increase in the Ion/Ioff 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 In0.53Ga0.47 As n(+)/p junctions, which is consistent with passivation of midgap defects in In0.53Ga0.47 As by the FGA process.