Effect of Oxygen for Ultra-Thin La{sub}2O{sub}3 Film Deposition

摘要

We fabricated MOS capacitors consisting of a La{sub}2O{sub}3 dielectric with small EOT of 0.59 nm and a W electrode. By supplying oxygen during La{sub}2O{sub}3 deposition, La-silicate was formed at La{sub}2O{sub}3/Si interface. The La{sub}2O{sub}3 and La-silicate dielectric constant was 23.4 and 14.4, respectively. The depth of the trap potential well was small, compared to without oxygen. These differences resulted from the quantity of oxygen vacancy. Concerning the variation of annealing, stable capacitance and flat-band voltage were obtained up to 300°C annealing. However, SiO{sub}x based interfacial layer formation was observed above 500°C annealing.