Formation of Vapour-Deposited SnO2 Thin Films Studied by Rutherford Backscattering

Abstract

SnO₂ films were prepared by evaporating SnO or SnO₂ powder onto substrates kept at various temperatures. The composition x for “as-deposited” films was determined by RBS and was found to have a wide range of values between 1.0 and 1.6, depending on the evaporation conditions. SnO₂ film was formed by annealing “as-deposited” SnO₂ film in an O₂ atmosphere. With increasing annealing time, x increased, finally reaching the stoichiometric value of 2.0, and the complete formation of SnO₂ was confirmed by X-ray diffraction and electron microscopy. It was also found that oxygen atoms penetrate into the film with a concentration gradient in the depth direction of the film. The electrical conductivity and Hall coefficient were measured for specimens annealed at 550°C for various time intervals.