Abstract: | Tantalum pentoxide thin layers (10–100 nm) obtained by thermal oxidation of rf sputtered Ta films on Si have been investigated with respect of their dielectric, structural and electric properties. It is established that stoichiometric Ta2O5 detected at the surface of the layers is reduced to tantalum suboxides in their depth. The oxide parameters are discussed in terms of a presence of an unavoidable ultrathin SiO2 between Si and Ta2O5 and bond defects in both the oxide and the interface transition region. Conditions which guarantee obtaining high quality tantalum oxide with a dielectric constant of 32–35 and a leakage current less than 10−7–10−8 A/cm2 at 1.5 V (SiO2 equivalent thickness of 2.5–3 nm) are established. These specifications make the layers obtained suitable alternative to SiO2 for high density DRAMs application. |