Electrical characterization and dielectric properties of metal-oxide-semiconductor structures using high-K CeZrO₄ ternary oxide as gate dielectric

In this work, high-k 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 (δV_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 x 10^-3 and 3 x 10^-5 A/cm² obtained at +2 and -2 V biases, respectively. A relative dielectric constant (δ_r) of 24.3 and an effective oxide thickness (EOT) of 1.7 nm were achieved.