Characterization of Mg Diffusion into HfO2/SiO2/Si(100) Stacked Structures and Its Impact on Detect State Densities

A stacked structure consisting of ∼1nm-thick MgO and 4nm-thick HfO2 was formed on thermally grown SiO2/Si(100) by MOCVD using dipivaloymethanato (DPM) precursors, and the influences of N2 anneal on interfacial reaction and defect state density in this stacked structure were examined. The chemical bonding features of Mg atom were evaluated by using an Auger parameter independently of positive charge-up during XPS measurements. With Mg incorporation into HfO2, a slight decrease in the oxidation number of Mg was detectable. The result suggests that Mg atoms are incorporated preferentially near oxygen vacancies in the HfO2, which can be responsible for a reduction of the flat band voltage shifts observed from C-V characteristics.