Trap-assisted tunneling, capacitance–voltage characteristics, and surface properties of Sm₂O₃ thin film on Si substrate

Abstract

The morphology, topography, and electrical properties of sputtered pure samarium metal film on silicon substrates which thermal oxidized in oxygen ambient at various temperatures (600–900 °C) for 15 min had been investigated quantitatively. Effects of oxidation temperature on the morphology, topography, and electrical properties of Sm₂O₃ thin film were reported. Metal–oxide–semiconductor capacitors were fabricated before current–voltage measurement and capacitance–voltage measurement. The roughness and uniformity of Sm₂O₃ thin films were revealed by scanning electron microscope and atomic force microscopy analysis. The sample oxidized at 700 °C demonstrated the highest electrical breakdown field (0.7 MV cm⁻¹), lowest leakage current density (10⁻⁴ A cm⁻²), highest barrier height value (2.13 eV), highest trap energy (0.00075 eV), lowest trap density (6.88 × 10²¹ cm⁻³), highest capacitance (1050 pF), and highest effective dielectric constant (214). This is attributed to the lowest effective oxide charge (2.81 × 10¹³ cm⁻²), slow trap charge density (5.56 × 10¹² cm⁻²), average interface trap density (~10¹⁴ eV⁻¹ cm⁻²), and total interface trap density (7.31 × 10¹³ cm⁻²).