Oxide surface cleaning by an atmospheric pressure plasma

In this study, an atmospheric pressure plasma was generated using a dielectric barrier discharge (DBD) with a perforated dielectric covered electrode and its effect on the cleaning of organic materials on oxides such as indium tin oxide (ITO) and magnesium oxide (MgO) was investigated. He and O2 were used as the ignition gas and cleaning gas, respectively. In addition to these gases, N2 was added to improve the effect of surface cleaning. A small addition of O2 to He increased the surface-cleaning rate due to the increase of oxygen radicals in the plasmas; however, further addition of oxygen decreased the surface-cleaning rate, possibly due to the decrease of plasma density by the formation of oxygen negative ions between oxygen molecules and electrons in the plasma. The additional mixture of N2 to He/O2 further increased the surface cleaning possibly due to the increased dissociation of O2 in the plasma resulting in the increased chemical reaction and removal from the surface. Surface characteristics after the plasma treatment were investigated using X-ray photoelectron spectroscopy (XPS), and showed a decrease of carbon contaminants on the ITO and MgO by the atmospheric pressure plasma treatment. After plasma treatment of the surfaces, the decrease of contact angles of water was also measured.