In0.53Ga0.47As FinFETs with self-aligned molybdenum contacts and HfO2/Al2O3 gate dielectric

InGaAs channel FinFETs with self-aligned molybdenum (Mo) contacts was demonstrated using a gate-last process. By realizing Mo contacts on in situ doped n++ InGaAs source and drain and self-aligned to channel, the FinFETs achieved series resistance of ∼250 Ω μm, which is the lowest value reported-to-date for InGaAs non-planar n-MOSFETs. A FinFET with channel length of 500 nm and equivalent oxide thickness (EOT) of 3 nm has an on-state/off-state current ratio of ∼105 and peak extrinsic transconductance of 255 μS/μm at drain voltage of 0.5 V. To further reduce EOT, atomic-layer-deposited HfO2/Al2O3 high-k dielectric was integrated in InGaAs FinFETs. Good interface quality and small EOT of ∼1 nm were achieved. Forming gas annealing (FGA) was used for drive current enhancement. A 300 °C 30 min FGA leads to ∼48% increase in drive current as well as significant reduction of subthreshold swing, probably due to an improvement of the HfO2/Al2O3/InGaAs interface quality.

► Self-aligned Mo contacts were integrated in InGaAs FinFETs for the first time. ► The FinFETs show lowest series resistance of ∼250 Ω μm among the values reported for InGaAs FinFETs. ► HfO2/Al2O3 dual-layer high k gate dielectric was integrated in InGaAs FinFETs to achieve ∼1 nm EOT. ► The effect of forming gas annealing on InGaAs FinFET performance was studied.