Epitaxial, well-ordered ceria/lanthana high-k gate dielectrics on silicon

Abstract

It is shown that the growth of epitaxial lanthana films on silicon may be achieved by substrate prepassivation using an atomic layer of chlorine, which prevents silicon oxide and silicate formation at the oxide–silicon interface. Postdeposition of two layers of cerium oxide facilitates the healing of structural defects within the La2O3 film, strongly increasing its crystallinity at the expense of a slightly more oxidized interfacial layer below. Together, the approach of combining Cl prepassivation and the ceria overgrowth results in an epitaxial, high-quality ceria/lanthana gate stack suitable for high-k integration in a gate-last process.