Synthesis of a tin compound bearing N-alkoxy carboxamide and methyl ligands as a precursor for SnO2 fabrication via atomic layer deposition

We synthesized a novel tin precursor and deposited SnO 2 thin films to demonstrate their excellent applicability in gas-sensor technology. The novel SnMe 3 (EDPA) (EDPA, N-ethoxy-2,2-dimethylcarboxylicpropanamide) precursor was analyzed using thermogravimetric analysis (TGA), which revealed complete mass loss at 155 °C with negligible residue. The temperature of SnMe 3 (EDPA) under 1 Torr vapor pressure was 25 °C. We successfully deposited tin oxide via atomic layer deposition (ALD) using SnMe 3 (EDPA) and O 2 plasma as reactants. The film growth behavior of SnO 2 thin films deposited via the ALD process exhibited typical surface-limited reaction characteristics and a crystal structure of tetragonal tin dioxide. The films had an optical bandgap of 3.5–3.6 eV and a refractive index of ∼1.9, which is a typical optical property of SnO 2 . Further, we confirmed that there were almost no impurities and that it was an n-type material. Consequently, our experimental results showed that the SnMe 3 (EDPA) precursor is suitable for the ALD process. The chemical sensing experiments demonstrated the superiority of films deposited using the novel precursor, which significantly exceeded the performances reported in previous studies.