Effect of hygroscopic nature on the electrical characteristics of lanthanide oxides (Pr2O3, Sm2O3, Gd2O3, and Dy2O3)

The hygroscopic nature of lanthanide oxides such as Pr2O3, Sm2O3, Gd2O3, and Dy2O3 was characterized by means of x-ray photoelectron spectroscopy and its effect on the electrical characteristics of the compounds was investigated. Among the four samples, Pr2O3 was found to be the most reactive with water which can be attributed to the relatively large ionic radius and lower electronegativity of Pr. In contrast, Dy2O3 was the least reactive with water. A direct correlation between the hygroscopicity and electronegativity of lanthanide elements was found. With increasing hygroscopicity, a significant growth of interfacial oxide with annealing temperature was observed. A clear understanding of the nature of hygroscopic effects and the optimization of process flow will be needed for future high-k gate dielectric application. (C) 2003 American Institute of Physics.