Ge-Interface Engineering With Ozone Oxidation for Low Interface-State Density

Passivation of Ge has been a critical issue for Ge MOS applications in future technology nodes. In this letter, we introduce ozone oxidation to engineer Ge/insulator interface. Density of interface states (D
_it
) across the bandgap and close to the conduction band edge was extracted using conductance technique at low temperatures. D
_it
dependence on growth conditions was studied. Minimum D
_it
of 3 times 10
¹¹
cm
^-2
V
^-1
was demonstrated. Physical quality of the interface was investigated through Ge 3d spectra measurements. We found that the interface and D
_it
are strongly affected by the distribution of oxidation states and the quality of the suboxide.