Ternary rare-earth metal oxide high-$k$ layers on silicon oxide

Ternary oxides, $GdScO3$⁠, $DyScO3$⁠, and $LaScO3$⁠, deposited by pulsed laser deposition using ceramics targets of stoichiometric composition, were studied as alternative high-$k$ gate dielectrics on (100) Si. Their physical characterization was done using Rutherford backscattering, spectroscopic ellipsometry, x-ray diffraction, and transmission electron microscopy on blanket layers deposited on (100) Si, and electrical characterization on capacitors. It is found that $DyScO3$ and $GdScO3$ preserve their amorphous phases up to $1000°C$⁠. Other encouraging properties for high $k$ applications were demonstrated, including $k$-value $∼22$⁠, almost no hysteresis or frequency dispersion in $C–V$ curves, and leakage current reduction comparable to that of $HfO2$ of the same equivalent oxide thickness.