Impact of H2 High-Pressure Annealing Onto InGaAs Quantum-Well Metal–Oxide–Semiconductor Field-Effect Transistors With Al2O3/HfO2 Gate-Stack

We report on the impact of H
₂
high-pressure annealing (HPA) onto In
_0.7
Ga
_0.3
As MOSCAPs and quantum-well (QW) MOSFETs with Al
₂
O
₃
/HfO
₂
gate-stack. After HPA with process condition of 300°C, H
₂
ambient and pressure of 20 atm, we observed notable improvements of the capacitance-voltage (CV) characteristics in InGaAs MOSCAPs with Al
₂
O
₃
/HfO
₂
gate-stack, such as reduction of equivalent-oxide-thickness and less frequency dispersion in the accumulation region. There was 20% improvement of the interfacial trap density (Dit). Then, we incorporated the HPA process into the fabrication of sub-100-nm In
_0.7
Ga
_0.3
As QW MOSFETs, to investigate the impact of HPA process. After HPA process, the device with L
_g
= 50 nm exhibits improved subthreshold-swing (SS) = 105 mV/decade, in comparison with SS = 130 mV/decade for the reference device without HPA process. Finally, we carried out reliability assessment under a constant-voltage-stress (CVS), and it turns out that the HPA process was effective in mitigating a shift of threshold voltage (ΔV
_T
) during the CVS. These are attributed to the effective passivation of oxide traps in the high-k dielectric layer and interfacial traps, after HPA process in the H
₂
ambient.