Structural, electronic, and dielectric properties of ultrathin zirconia films on silicon

摘要

As high-permittivity dielectrics approach use in metal-oxide-semiconductor field-effect transistor production, an atomic level understanding of their dielectric properties and the capacitance of structures made from them is being rigorously pursued. We and others have shown that crystal structure of ZrO_2 films have considerable effects on permittivity as well as band gap. The as-deposited films reported here appear amorphous below a critical thickness (～5.4 nm) and transform to a predominantly tetragonal phase upon annealing. At much higher thickness the stable monoclinic phase will be favored. These phase changes may have a significant effect on channel mobility.