A Deposition of Cu-O Thin Films by Low Energy Oxygen Ion Assisted Evaporarion Method

Abstract

Ion assisted deposition is very useful method for obtaining the films with desired properties. The role of ions in this method is to give kinetic energy and chemical activity to a substrate or a growing film. Using a reactive gas ion, it is able to react on the deposition atoms. Consequently various compounds are formed. Control of the incident ion energy, curret and/or the ion species makes to be possible to regulate the film properties such as density, crystal structure, electrical resistivity and so on. We have ever developed a new type of ion source with low energy and high current density. It was discussed that the effects of ion kinetic energy and ion current on the crystal structure of Cu-O thin films prepared by oxygen ion assisted deposition using the ion source developed by us.
The crystal structure of Cu-O films were prepared in various ion energy and current was studied by X-ray diffraction measurement. The following results were obtained:
(1) The X-ray diffraction peaks due to Cu₂O crystal structure are appeared, in spite of low current bombardment of oxygen ion (ion current : O.1mA).
(2) As ion current is increased from 0.1mA to 1.2mA and from 1.2mA to 4.4mA at adequate acceleration voltage, the crystal structure of the prepared films is changed as follows, Cu-Cu₂O system --> Cu₂O system --> CuO system.