Compositional Study of Surface, Film, and Interface of Photoresist-Free Patternable SnO2Thin Film on Si Substrate Prepared by Photochemical Metal-Organic Deposition

Abstract

The direct-patternable <TEX>$SnO_2$</TEX> thin film was successfully fabricated by photochemical metal-organic deposition. The composition and chemical bonding state of <TEX>$SnO_2$</TEX> thin film were analyzed by using X-ray photoelectron spectroscopy (XPS) from the surface to the interface with Si substrate. XPS depth profiling analysis allowed the determination of the atomic composition in <TEX>$SnO_2$</TEX> film as a function of depth through the evolution of four elements of C 1s, Si 2p, Sn 3d, and O 1s core level peaks. At the top surface, nearly stoichiometric <TEX>$SnO_2$</TEX> composition (O/Sn ratio is 1.92.) was observed due to surface oxidation but deficiency of oxygen was increased to the interface of patterned <TEX>$SnO_2/Si$</TEX> substrate where the O/Sn ratio was about 1.73~1.75 at the films. This O deficient state of the film may act as an n-type semiconductor and allow <TEX>$SnO_2$</TEX> to be applied as a transparent electrode in optoelectronic applications.