Morphological Evolution of ZnO Thin Films Deposited by Reactive Sputtering

• Published in: Crystal growth & design Vol. 4; no. 1; pp. 147 - 156
• Main Authors: Mirica, Eugenia, Kowach, Glen, Evans, Paul, Du, Henry
• Format: Journal Article
• Language: English
• Published: Washington,DC American Chemical Society 01.01.2004
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Scanning electron microscopy; Inorganic compounds; Electron diffraction; Transition element compounds; Binary compounds; Field emission; Crystal growth from vapors; XRD; Surface diffusion; Experimental study; Texture; Thin films; Magnetrons; Zinc oxides; Transmission electron microscopy; Morphology; Reactive sputtering; Microstructure
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg025595j

The morphological evolution of ZnO thin films deposited by magnetron sputtering has been investigated on two types of substrates, (111) textured Pt and (100) Si possessing a native oxide. The ZnO films are oriented with the c-axis [0001] normal to the substrate and possess varying degrees of crystallinity. The films have a columnar structure with column diameters in the range of 40−300 nm. As observed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray diffraction, the film microstructure is strongly dependent on substrate temperature during deposition in the range from near room temperature up to 700 °C and is also dependent on substrate type. A textured film of platinum promotes nucleation thereby improving the crystallinity and texture of sputtered ZnO films. A mechanism for morphological evolution of the films via surface diffusion is proposed based on atom mobilities.