The interfacial quality of HfO₂ on silicon with different thicknesses of the chemical oxide interfacial layer

We studied the effects of the thickness variation of the chemical oxide interfacial layer (IL) on the interfacial quality of the HfO₂ /Si system in this paper. Metal-oxide-semiconductor (MOS) capacitors using the HfO₂ /IL gate oxide stack were fabricated using the Ni/Ti metal gate. The capacitance-voltage and ellipsometry measurements suggest that the chemical oxide interfacial layer of ∼0.45 nm is the minimum requirement for atomic layer deposition growth of high quality HfO₂ on silicon and thicker chemical oxide ILs (<0.45 nm) result in better interfaces for HfO₂ MOS structures with equivalent oxide thicknesses of <1 nm.