Influence of applied voltage on the physical and electrical properties of anodic Sm2O3 thin films on Si in 0.01 M NaOH solution

Formation of anodic samarium oxide thin film by anodisation of 15 nm thin sputtered samarium metal on silicon substrate was systematically investigated. Sputtered Sm on Si substrate was followed by anodisation in 0.01 M NaOH (pH 11) at various applied voltages (10, 15, 20, and 25 V). All anodisation processes were performed for 10 min at room temperature in the bath with constant stirring. The crystallinity of Sm2O3 film was evaluated by X-ray diffraction analysis. The crystallite size of Sm2O3 was calculated by Scherrer equation. The cross-section of 20 V sample was examined by high-resolution transmission electron microscope. The sample anodised at 20 V demonstrated the highest electrical breakdown field of 9.50 MV/cm at 10(-4) A/cm(2). This is attributed to the lowest effective oxide charge, slow trap charge density, average interface trap density, and total interface trap density.