Structures and Properties of ZnO-Based Ceramic Films for Low-Voltage Varistors by the R.F. Magnetron Sputtering

Abstract

ZnO-based ceramic targets with 50mm in diameter and 3mm in depth were prepared by the traditional solid-state sintering process. ZnO-based ceramic films were deposited on Au/Si substrates by R.F. magnetron sputtering using ZnO-based ceramic target. The films have been characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy. The ZnO-based ceramic films, with thickness close to 1 μm, show a good c-axis orientation, corresponding to vertical growth with respect to the substrate. The surface of the films looks very smooth and dense, and the films are the same composition as the ZnO ceramic target composed of Zn, Bi, Sb, Co, Cr and Mn. The ZnO-based ceramic films with nonlinear coefficient of 6.4, nonlinear voltage of 1.6V and the leakage current density 0.3μA/mm2 could be achieved.