Study on the crystalline structure and the thermal stability of silver-oxide films deposited by using direct-current reactive magnetron sputtering methods

Silver-oxide (AgxO) films were deposited on glass substrates by direct-current reactive magnetron sputtering at different oxygen flux ratios (OFR = [O2]/[Ar]) and substrate temperatures (Ts). An X-ray diffraction analysis indicates that the AgxO films are biphased (Ag + Ag2O) when deposited at low OFR values and that Ag2O-dominated AgxO film can only be synthesized at higher OFR values, as confirmed by X-ray photoelectron spectroscopy. This result may be due to the Ag2O phase being preferably produced at high OFR value. The AgO phase is thermodynamically unstable compared with the Ag2O phase. In order to further offer deep insight into the film's thermal stability, Ag2O-dominated AgxO films were thermally treated by using a rapid thermal processing technique at different annealing temperatures for different annealing times. The Ag2O phase is thermodynamically stable at temperatures below the threshold of the thermal decomposition temperature which approaches 175 .deg. C. The domination of the Ag2O phase in the AgxO film may be attributed to the chain reaction AgO → Ag2O <-> Ag + O, AgO + Ag → Ag2O.