Passivation effect of zinc oxide thin films with temperature on Si (100) substrate by atomic layer deposition

The thin film growth behavior and mechanism of ZnO grown by atomic layer deposition (ALD) on Si (100) substrate was using diethylzinc (DEZn) and H2O as the zinc and oxygen sources, resperctively. The preferred orientation of ZnO on the Si (100) substrate was changed from (002) to (100). We suggest a hypothesis on the mechanism of preferred orientation change during ZnO deposition. This phenomenon seemed to play a major role in the vertical growth of (001) plane parallel to the substrate, which resulted in (002) preferred orientation growth of the ZnO films at low temperature regions. At high temperatures, the ethyl fragments further decomposed and desorbed from the surface. Therefore, the passivation effect disappeared and suppression of (002) growth was no longer possible. The microstructure evolution of ZnO was investigated by using a field emission scanning electron microscope (FeSEM) and x-ray diffraction (XRD).