Formation of a stratified lanthanum silicate dielectric by reaction with Si(001)

We have characterized the structure and electrical properties of lanthanum silicate layers formed on Si(001) by reaction of lanthanum oxide with the s ubstrate. Postoxidation of the deposited films results in the formation of a stacked dielectric with a lanthanum silicate layer atop an interfacial la yer of SiO2. This structure combines the interfacial properties of SiO2 wit h the large permittivity of lanthanum silicate. Although the resulting film has leakage properties far superior to an equivalent thickness of SiO2, th ere is evidence of significant quantities of ionic charge that must be elim inated before use in electronic applications. (C) 2001 American Institute o f Physics.