Chemical activity of oxygen atoms in the magnetron sputter-deposited ZnO films

• Published in: Thin solid films 2011-08, Vol.519 (20), p.6903-6909
• Main Authors: Morita, Aya, Watanabe, Ikuo, Shirai, Hajime
• Format: Article
• Language: English
• Subjects: Annealing; Chemical annealing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal defects; Crystallization; Deposition by sputtering; Diffusion; Diffusion annealing; Diffusion; interface formation; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Lattice vacancies; Layer-by-layer deposition; Magnetron sputtering; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Oxygen atoms; Physics; Solid surfaces and solid-solid interfaces; Surface and interface electron states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of film growth; Zinc oxide; ZnO
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.11.055

The role of oxygen atoms in the growth of magnetron sputter-deposited ZnO films was studied by alternating the deposition of a several-nanometer-thick ZnO layer and an O 2/Ar mixed plasma exposure, i.e., a layer-by-layer (LbL) technique. The film crystallization was promoted by suppressing the oxygen vacancy and interstitial defects by adjusting the exposure conditions of the O 2/Ar plasma. These findings suggest that the chemical potential of the oxygen atom influences the film crystallization and the electronic state. The diffusion and effusion of oxygen atoms at the growing surface have an effect similar to that of thermal annealing, promoted film crystallization and the creation and the annihilation of oxygen- and zinc-related defects. The role of oxygen atoms reaching at the growing film surface is discussed in terms of chemical annealing and a possible oxygen diffusion mechanism is proposed.