Atomic layer deposition of vanadium oxide thin films from tetrakis(dimethylamino)vanadium precursor

摘要

Atomic layer deposition (ALD) of vanadium oxide (VO_x) thin films, using tetrakis(dimethyla-mino)vanadium as the vanadium precursor, is comprehensively reported in this work. The vanadium precursor is highly volatile and can be used at room temperature for deposition. Either H_2O or O_3 can be used as the coreactant for depositing VO_x at 50-200 ℃. However, partial precursor decomposition is suggested for the deposition temperature higher than 160 ℃. The as-deposited VO_x films are pure, smooth, and amorphous, and can be crystallized into monoclinic VO_2 phase by postdeposition annealing under N_2 ambient. The minimum annealing temperature for film to crystallize is found, by in situ high-temperature X-ray diffraction experiments, at around 550-600 ℃. In situ quartz crystal microbalance experiments are performed to further analyze the surface reaction mechanism involved in this ALD process.