Atomic layer deposition of SnO₂ thin films using tetraethyltin and H₂O₂

The atomic layer deposition (ALD) of SnO₂ films has drawn interest from many researchers as a way to enhance the performance of functional materials for emerging applications such as transistors, sensors, and transparent electrodes. Among the critical issues in the exploitation of SnO₂ ALD in industrial applications is the lack of commercially available Sn precursors. Here, we demonstrate an ALD process for SnO₂ films using commercially available tetraethyltin (TET) as a precursor. H₂O₂ is used as the oxygen source to overcome the lack of reactivity between TET and H₂O, consequently the reaction of TET and H₂O₂ results in the growth of SnO₂ films. The ALD process has a wide ALD window of 250–400 °C. In the range of the growth temperature, the grown films show a high density of ~6.2 g/cm³ and an optical band gap of 3.7–3.9 eV, which is comparable to that of bulk SnO₂. Negligible impurities remained in the films grown over the entire temperature range. The crystallization behavior and electrical properties of the SnO₂ films were examined as well. The ability of this ALD process to produce high-quality SnO₂ films with a commercially available tin precursor will allow it to be exploited in various applications.