Abstract
The crystallographic character of ZnO thin films formed by the rf sputtering technique were investigated using X-ray diffraction and RHEED. When the sputtering gas pressure is 5×10-3 Torr, there is no preferred orientation of the crystal axis near the surface of ZnO thin film, but below its surface, the c-axis is oriented normal to the substrate within a certain distribution angle. The crystallites reorient so that the c-axes are normal to the substrate as new surface layers are formed.