(Ta_(1-x)Nb_(x))_(2)O_(5) films produced by atomic layer deposition: Temperature dependent dielectric spectroscopy and room-temperature I-V characteristics

摘要

Temperature dependent ac dielectric spectroscopy and room-temperature I- V characterization were performed on atomic layer deposited (Ta_(1-x)Nb_(x))_(2)O_(5) films. The high frequency permittivity, as well as the dc conductivity of the films, were found to increase with increasing Nb content. The conduction mechanism in the mixed Ta-Nb oxide films was of the Poole-Frenkel type, while the high field conduction in pure Ta_(2)O_(5) was space-charge limited. The activation energy for dc conduction was higher in mixed Ta-Nb oxides compared to pure Ta_(2)O_(5) and Nb_(2)O_(5) films. Irreversible changes in the conduction mechanism took place upon heat treatment above a certain irreversibility temperature. This temperature was higher for the mixed oxides than for the binary ones.