Samarium oxide thin films deposited by reactive sputtering: Effects of sputtering power and substrate temperature on microstructure, morphology and electrical properties

In this study, the effects of increase in sputtering power and substrate temperature on the microstructural, morphological and electrical characteristics of Sm2O3 thin films have been reported. All films were deposited at 50 °C with varying in sputtering power from 100 to 250 W in 50 W steps by the reactive sputtering technique. The crystallization, grain size, and d-spacing of the films were determined by an X-ray diffractometer (XRD). The semi-quantitative compositional changes were investigated by energy-dispersive X-ray (EDX) spectroscopy while microstructural and morphological modifications were studied by atomic force microscopy (AFM). In addition, the electrical evolutions of the films were determined by alternating current (a.c.) conductivity. It was observed that the crystallization of the films was increased with increase in sputtering power up to 200 W and decreased at the power of 250 W. Therefore, the films deposited at 200 W were annealed at 50 °C, 125 °C, and 200 °C, and a continuous crystallization improvement was observed. The composition of the films was improved by both sputtering power and increase in substrate temperature. The grain boundaries and surface roughness of the films were also found to be significantly affected by the change in substrate temperature. The a.c. conductivity of the films gradually decreases from 1.10×108 Ω−1 cm−1 to 2.50×106 Ω−1 cm−1 by increase in sputtering power and substrate temperature. The results show that the Sm2O3 thin films fabricated at 200 W sputtering power and 200 °C substrate temperature exhibit requested structural and morphological characteristics.