Study of Annealed NiO Thin Films Sputtered on Unheated Substrate

Nickel oxide (NiO) thin films were deposited on unheated Si substrates by reactive dc magnetron sputtering. Post-deposition annealing was carried out for NiO films in dry air. The effect of annealing temperature (from 500 to 900°C) on the structural, compositional and surface morphological properties of thin NiO films was investigated. The films were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and atomic force microscopy (AFM). Only the as-deposited films in the metal-sputtering mode were crystalline. Annealing in dry air led to the formation of crystalline phases in all samples. During the annealing process, changes in the crystal structure occurred. All examined NiO films were semiconductors and their conductance increased by four orders of magnitude between 25 and 350°C.