Trap-assisted tunneling, capacitance-voltage characteristics, and surface properties of Sm_2O_3 thin film on Si substrate

摘要

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 ℃) for 15 min had been investigated quantitatively. Effects of oxidation temperature on the morphology, topography, and electrical properties of Sm_2O_3 thin film were reported. Metal-oxide-semiconductor capacitors were fabricated before current-voltage measurement and capacitance-voltage measurement. The roughness and uniformity of Sm_2O_3 thin films were revealed by scanning electron microscope and atomic force microscopy analysis. The sample oxidized at 700 ℃ 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 × 10~(21) cm~(-3)), highest capacitance (1050 pF), and highest effective dielectric constant (214). This is attributed to the lowest effective oxide charge (2.81 × 10~(13) cm~(-2)), slow trap charge density (5.56 × 10~(12) cm~(-2)), average interface trap density (~ 10~(14) eV~(-1) cm~(-2)), and total interface trap density (7.31 × 10~(13) cm~(-2)).