Thin Film Growth of Zinc Oxide by Vapor Phase Epitaxy

Zinc Oxide is a potentially valuable semiconductor with photoconducting, piezoelectric, optoelectronic, and optical waveguide applications. A technique for the growth of ZnO epitaxial layers is necessary for improved device fabrication. Previously, attempts at ZnO epitaxial growth were constrained to sapphire substrates using sputtering as the preferred preparation technique. However, with the present availability of single crystal ZnO substrates the hope of high quality epitaxial layers exists. The authors will discuss several possibilities for growth precursors, and the resulting chemical reactions required for the formation of ZnO. This presentation discusses the growth of ZnO epitaxial layers by chemical vapor deposition without using metal-organic compounds. The thermodynamics and predicted growth rates for several reactions are presented as well as the preliminary growth results. The preliminary growths are characterized with the aid of Hall Effect measurements, providing information on resistivity, Hall mobility, and carrier concentration.