Structural characterization of amorphous Ta2O5 and SiO2–Ta2O5 used as solid electrolyte for nonvolatile switches.

Diffusivity of Cu in amorphous (a-) Ta2O5 is increased by low temperature annealing above 350 °C but the increase is suppressed by adding SiO2 to Ta2O5. To clarify the reasons, we investigated the structural difference between a-Ta2O5 and a-SiO2–Ta2O5. The results show that the low temperature annealing does not cause polycrystallization of Ta2O5 but purges weakly bonded oxygen atoms from the bulk and decreases the film density. Adding SiO2 to Ta2O5 is shown to increase the coordination number of Ta–O, which results in the improved thermal stability. [ABSTRACT FROM AUTHOR]