Investigation of the effect of adding a moderate amount of hydrogen on the properties of tin oxide films deposited by DC magnetron sputtering

Abstract

We investigated the effect of adding small amounts of hydrogen during DC magnetron sputtering of SnO x films followed by annealing in a nitrogen atmosphere at temperatures below the instability of SnO. Hard X-ray photoelectron spectroscopy analysis showed a difference in the initial Sn content in the as-deposited samples, which suggests an increased number of V Sn vacancies. This led to the formation of V Sn -H complexes, resulting in a doubling of the concentration of holes from 5.89 × 1017 cm−3 to 1.38 × 1018 cm−3 and a slight increase in the mobility from 1.17 cm2/(Vs) to 1.45 cm2/(Vs) after annealing. Thermal desorption spectroscopy revealed increased desorption of hydroxyl groups after the addition of hydrogen, indicating that hydrogen presence in the film as OH bonds may be the reason for the undesired increase in SnO2 content and raising of the crystallization point. The average transmittance of the hydrogen-added sample was 10% greater than that of the hydrogen-free sample.