Effect of the presence of Ge in Er compound on the barrier height formation of Er-Si contacts

Abstract

The barrier heights of Er and ErSi2 on oxide-free p-Si have been reported to be identical (φpB ∼0.8 eV), suggesting that the stoichiometry of the metallic contact does not appear to affect the barrier heights as long as a specific metal is present at the interface. In this work, the effects of Ge in the Er film on the barrier height have been investigated. Our results show that the ratio of Ge to Er in an Er/(GexSi1−x)2 compound layer in contact with p-Si affects the barrier heights significantly. A linear relationship between φpB and x has been found and can be expressed as φpB =0.778 −(2x) (0.098). This experimental finding indicates that the barrier height of a metallic compound on Si may depend not only on the metal species, but also on the composition of the compound.