Ultrathin zirconia/SiO2 dielectric stacks grown by ultraviolet–ozone oxidation

High-dielectric-constant materials such as zirconia are currently being investigated to replace SiO2 as the gate dielectric in future complementary metal–oxide–semiconductor devices. In this letter, we present the electrical properties of ultrathin zirconia/SiO2 dielectric stacks in which both layers are grown in situ at room temperature by the ultraviolet–ozone oxidation technique. A capacitance-based equivalent oxide thickness of 15 Å (without accounting for quantum-mechanical corrections), leakage current of 1.8×10−4 A/cm2 at 1 V from flatband, and negligible hysteresis has been obtained from these films. It is shown that in order to grow dielectric stacks of high electrical quality, it is important to understand the oxidation kinetics of these films.