Epitaxial Growth of Metal(CoSi₂)/Insulator(CaF₂) Nanometer-Thick Layered Structure on Si(111)

Abstract

Epitaxial growth of a metal(CoSi 2 )/insulator(CaF 2 ) nanometer-thick layered structure on Si(111) was demonstrated. An epitaxial CoSi 2 layer on CaF 2 was obtained by the two-step growth technique, i.e., solid phase epitaxy with the epitaxial Si layer grown in the first step and Co deposited in the second step. This technique was shown to be effective in avoiding the Co agglomeration on the CaF 2 layer observed in the co-evaporation of Si and Co. An epitaxial CaF 2 layer was formed on CoSi 2 /CaF 2 at low substrate temperature (450°C) with a partially ionized and accelerated CaF 2 beam, to avoid Co agglomeration in the CoSi 2 /CaF 2 underlayer as well. Obtained results showed a single-crystalline nature in reflection high-energy electron diffraction (RHEED) and transmission electron microscopy (TEM) observations.