A study on phase transformation of SnOx thin films prepared by reactive magnetron sputtering

Abstract

In the paper, SnOx thin films were deposited by reactive magnetron sputtering from a tin target in O2 containing working gas. The evolution from Sn-containing SnO to tetravalent SnO2 films was investigated. The films could be classified into three groups according to their optical band gaps, which are Eg<2.5eV, Eg=3.0–3.3eV and Eg>3.7eV. The electric measurements show that high conductivity can be obtained much easier in SnO2 than in SnO films. A high electron mobility of 15.7cm2V−1s−1, a carrier concentration of 1.43×1020cm−3 and a resistivity of 2.8×10−3Ωcm have been achieved in amorphous SnO2 films. Films with the optical band gap of 3.0–3.3eV remain amorphous though the substrate temperature is as high as 300°C, which implies that °btaining high mobility in p-type SnO is more challenging in contrast to n-type SnO2 films.