Surface roughness of sputtered ZnO films

Abstract

ZnO films are grown on Si and glass substrates by radio-frequency (RF) magnetron sputtering. The crystalline structures are investigated by x- ray diffraction (XRD). Moreover, the roughness characteristics of the films are examined by atomic force microscopy (AFM) and field-emission scanning electron microscopy (FE-SEM). All films exhibit strong ( 002) preferential orientation. The influence of the RF power and target-to-substrate distance (D-ts) on the properties of ZnO is studied. Under the optimized conditions of the RF power and D-ts, root-mean-square (RMS) surface roughnesses of < 0.8 nm are achieved.