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

摘要

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 degrees C. Other encouraging properties for high k applications were demonstrated, including k-value similar to 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. (C) 2005 American Institute of Physics.