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

摘要

Ternary oxides, GdScO_3, DyScO_3, and LaScO_3, 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 DyScO_3 and GdScO_3 preserve their amorphous phases up to 1000℃. 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 HfO_2 of the same equivalent oxide thickness.