The effect of substrate temperature on the physical properties of tantalum oxide thin films grown by reactive radio-frequency sputtering

Abstract

Thin films of TaO x were deposited on Si(1 0 0) by radio-frequency magnetron sputtering at substrate temperatures of 25, 100, 200, 300, 400, and 500 °C. The properties of TaO x thin films deposited with different oxygen-to-argon gas ratios and substrate temperatures were evaluated. The results show that the films with lowest leakage current density were obtained at ambient temperature with an oxygen mixture ratio (OMR) of 60% and the oxygen-to-tantalum ratio has a minimum with increasing deposition substrate temperature. From the current–voltage ( I– V) characteristics of the TaO x thin films as a function of deposition substrate temperature, we found that the leakage current density in the TaO x thin films increases with increasing deposition substrate temperature. The higher leakage current density in the TaO x films is correlated to the oxygen deficiency in TaO x films and crystallization at higher deposition temperature.