Structural properties and electrical characteristics of praseodymium oxide gate dielectrics

Structural properties and electrical characteristics of praseodymium oxide gate dielectrics grown on Si substrate by reactive rf sputtering were investigated. The structure, composition, and interfacial characteristics of these dielectrics were examined using X-ray diffraction and X-ray photoelectron spectroscopy. It is found that Pr2 O3 gate dielectric with TaN metal gate annealed at 700°C exhibits a higher capacitance value (∼450 pF, EOT=2.41 nm) and lower flatband voltage (∼-0.5 V) in C-V curves, and shows the leakage value of ∼5× 10-7 A cm2 at a bias of 2 V. They also show negligible charge trapping under high constant voltage stress. This phenomenon is attributed to a rather well-crystallized Pr2 O3 and the decrease of the interfacial layer and Pr silicate thickness.