Effects of substrates on the structural properties of ZnO films deposited by rf magnetron sputtering

Insulating films of silicon nitride (Si3N4) or aluminum oxide (Al2O3) were grown on dry-oxidized Si wafers, and then ZnO was deposited on the insulating films. The crystallographic properties of the films were studied by X-ray diffraction (XRD), and their surface morphologies were investigated by atomic force microscopy (AFM). A high-resolution micro-Raman spectrometer excited with a 514.5 nm argon laser was used to evaluate the quality of the ZnO films. Next, leakage currents flowing through the insulating films were measured. Finally, Auger electron spectroscopy (AES) was employed to track the diffusion of zinc atoms through the insulating films.