Influence of postdeposition annealing on physical and electrical properties of high-k Yb₂TiO₅ gate dielectrics

The structure and electrical properties of a high-k Yb₂TiO ₅ gate dielectric deposited on Si(100) substrates through reactive cosputtering were investigated. X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy were used to study the morphological and chemical features of these films as functions of the growth conditions. The Yb₂TiO₅ dielectrics annealed at 800°C exhibited a thinner capacitance equivalent thickness, a lower gate leakage current, a smaller density of interface state, and a relatively lower hysteresis voltage compared to those at other annealing temperatures. These results are attributed to the formation of a rather well-crystallized Yb₂TiO₅ structure and composition.