Electrical Characterization and Dielectric Properties of Metal–Oxide–Semiconductor Structures Using High-$\kappa$ CeZrO4 Ternary Oxide as Gate Dielectric

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In this work, high-$\kappa$ cerium zirconate (CeZrO4) was successfully fabricated by RF magnetron cosputtering with a postannealing temperature of 850 °C. The amount of Zr in CeO2 can be well controlled by adjusting the DC power of the Zr target. X-ray photoelectron spectroscopy (XPS) shows that CeZrO4 becomes amorphous with increasing DC power. The intensity of the CeZrO4 phase increases with increasing oxygen content in the plasma. The crystalline phases were confirmed using X-ray diffraction (XRD). The dielectric constant and flatband voltage shift ($\Delta V_{\text{FB}}$) as functions of DC power and oxygen gas flow rate were investigated. The optimum balance between leakage and dielectric constant was considered. The leakage current densities were $3\times 10^{-3}$ and $3\times 10^{-5}$ A/cm2 obtained at +2 and $-2$ V biases, respectively. A relative dielectric constant ($\varepsilon_{\text{r}}$) of 24.3 and an effective oxide thickness (EOT) of 1.7 nm were achieved.
2009-05-25