Structural and electrical characterization of ultrathin Er_2O_3 films grown on Si(001) by reactive evaporation

摘要

Stoichiometric, amorphous, uniform Er_2O_3 films are deposited on Si(001) substrates by reactive evaporation using a metallic Er source at room temperature in an oxygen ambient pressure of 9 x 10~(-6) Torr. Transmission electron microscopic measurement shows that the film possesses good thermal stability and forms a sharp interface with its Si substrate after annealing at 700 deg C for 30 min in ultrahigh vacuum. The effective dielectric constant (k) of the film is measured to be 12.6, and its effective oxide thickness (EOT) can reach 1.4 nm, with a low leakage current density of 8 x 10~(-4) A cm~(-2) at an electric field of 1 MV cm~(-1) after annealing. The characteristics obtained indicate that ultrathin amorphous Er_2O_3 film could be a promising candidate for a high-k gate dielectric in Si microelectronic devices.