Increment of the Dielectric Constant of Ta[sub 2]O[sub 5] Thin Films by Retarding Interface Oxide Growth on Si Substrates

The improved electrical properties of tantalum oxides grown by plasma-enhanced atomic layer deposition (PEALD) are presented. In PEALD, oxygen radicals were served as a reactant of at a deposition temperature of 260°C. The interface oxide layer, which was formed during the initial stage of the PEALD, retards its further growth during the annealing process at 700°C for 2 min in ambient, and is thought to be not pure but The stoichiometry of the as-deposited film is oxygen-rich, having no hydrocarbon impurity. As a result, on the films with a thickness of the leakage current density, dominated by Schottky emission, reduces to at 1 MV/cm, and the dielectric constant is obtained as high as even after the annealing process.