Structural and Electrical Characteristics of Amorphous ErAlO Gate Dielectric Films

Ultrathin high-k dielectric ErAlO films were deposited on Si (100) substrates by using radio-frequency magnetron sputtering. The very flat surface of the annealed film with a rms roughness less than 0.25 nm was observed by using an atomic force microscope. The film shows good thermal stability when annealing at 900°C for 30 s in the O₂ ambient. The effective dielectric constant of the film is around 15.2, and a low leakage current of 8.4×10^?5 A/cm² at an electric field of 1 MV/cm was achieved for the film with the equivalent oxide thickness of 2.0 nm after annealing.