Study of electrical and physical properties of PrxAl2−xO3 as metal-oxide-semiconductor gate dielectric

The electrical and physical properties of Pr_xAl_2-xO₃ on metal-oxide-semiconductor gate dielectric were investigated. Amorphous Pr_xAl_2-xO₃ films with the thickness of 15 nm were deposited by electron-beam evaporation under a typical dielectric constant and equivalent oxide thickness of 18 and 3.3 nm, respectively. Leakage current decreased from 48mA/cm² to 3.4mA/cm² at a gate voltage of 1V after 500°C annealing. The films still remained amorphous after 900°C annealing for 5 min. A mixture of Pr, Al, O and Si observed at the interface between the film and the substrate was argued to be Pr-Al-silicate. Post-annealing is demonstrated to be essential for the films in order to get good electrical property.