Crystalline zirconia oxide on silicon as alternative gate dielectrics

Epitaxial crystalline yittria-stabilized zirconia (YSZ) oxide films were grown on silicon wafers by the laser molecular beam epitaxy technique. The interface of crystalline YSZ film in contact with silicon was found to be atomically sharp and commensurately crystallized without an amorphous layer. An x-ray photoelectron spectroscopy depth profile and transmission electron microscopy investigation showed that no ${\mathrm{SiO}}_{\mathrm{2}}$ formed at the interface. For a film with electrical equivalent oxide thickness ${\mathrm{(t}}_{e\mathrm{ox}})$ 14.6 Å, the leakage current is about ${\text{1.1×10}}^{\text{−3}} {\mathrm{A/cm}}^{\mathrm{2}}$ at 1 V bias voltage. The hysteresis and interface state density in this film are measured to be less than 10 mV and ${\text{2.0×10}}^{11} {\mathrm{eV}}^{\mathrm{-1}}{\mathrm{ cm}}^{\mathrm{-2}},$ respectively.