The effects of deposition conditions on the structural properties of ZnO sputtered ®lms on sapphire substrates

Zinc oxide (ZnO) ®lms were deposited on (1 1 2 0) or (0 0 0 1) oriented sapphire substrates heated up to 8008C with a radio frequency (rf) power ranging from 40 to 200 Wat an argon gas pressure range 0.08±11.7 Pa by rf magnetron sputtering from a ZnO target, and the dependence of structural properties of these ®lms on the preparation conditions was studied by using XRD, RHEED, SEM and AFM. The results obtained by XRD and RHEED measurements showed that ®lms deposited on sapphire (1 1 2 0) plane were (0 0 0 1) oriented heteroepitaxially grown ®lms of mosaic structure independently of the deposition conditions and the crystallinity of ®lms was improved with increase in ®lm thickness and substrate temperature, and that most of the ®lms grown on sapphire (0 0 0 1) plane consisted of (0 0 0 1) oriented ®ber-texture crystallites, the degree of whose a-axis ordering was changed depending on the deposition conditions. # 2001 Elsevier Science B.V. All rights reserved