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

We investigated the effect of forming gas (5% H₂/95% N₂) annealing on surface-channel In_0.53 Ga_0.47As MOSFETs with atomic-layer-deposited Al₂O₃ 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 Al₂O₃ , 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_0.53Ga_0.47As n⁺/p junctions, which is consistent with passivation of midgap defects in In_0.53Ga_0.47As by the FGA process.