Pressure effects in ZnO films using off-axis sputtering deposition

ZnO films are deposited on (0 0 0 1) sapphire and quartz substrates using t he off-axis reactive magnetron sputtering deposition. Based on film thickne ss measurements, three transport regions of sputtered particles are observe d when films are deposited in the pressure regions of 5-150 mTorr, X-ray di ffraction, scanning probes microscopy, and electrical measurements are also used to characterize these films. The full-width at half-maximum of theta- rocking curves for epitaxial films is less than 0.5 degrees. In textured fi lms, it rises to several degrees. The epitaxial films deposited at high pre ssure reveal a flat surface with some hexagonal facets. The density of hexa gonal facets decreases when the growth pressure is reduced. The resistivity of these epitaxial films also depends on the growth pressures. A relations hip between the pressure effects and film properties are discussed. (C) 200 0 Elsevier Science B.V. All rights reserved.