Influence of oxidants on the characteristics of atomic layer deposited TiO2 thin films

Abstract

This study investigated the atomic layer deposition of TiO₂ thin films using H₂O and O₂ plasma as oxidants with titanium tri(dimethylamido)N’-ethoxy-N-methylacetimidamide (Ti(enno)(NMe₂)₃) as a precursor. The investigation examined the influence of these oxidants on the deposition behavior, film properties, and impact of rapid thermal annealing (RTA). The saturated growth per cycle was measured at 0.08 and 0.23 nm∙cy⁻¹ with H₂O and O₂ plasma, respectively. The films deposited with O₂ plasma exhibited lower carbon contamination and superior electrical properties. Moreover, the RTA further enhanced the crystallinity and reduced leakage currents. The measured dielectric constants ranged across 27.9–39.6 and 32.3–37.9 for H₂O and O₂ plasma, respectively. Furthermore, comparisons of the leakage current density and capacitance equivalent thickness (J_g-CET) revealed that the TiO₂ thin film using O₂ plasma and RTA at 1050 °C exhibited the best high-κ characteristics.