Properties of MeNxOy thin films prepared by reactive DC magnetron sputtering

Abstract

The addition of small amount of nitrogen to a growing MeOy (Me = Metal) film originates a new class of materials with a wide range of different properties, where the optical, electrical and mechanical ones may be tailored between those of the pure oxide, MeOy, and oxynitride, MeNxOy, films, according to the particular application envisaged. The main reason for this is related with the change in the nitride content (which can be either metallic or even insulating-type) of the films promoted by the increasing amounts of nitrogen that are introduced in the films. In this work thin films of MeNxOy were produced using reactive DC magnetron sputtering, using a metallic (Me) target and an Ar/(N2,O2) gas mixture. Preliminary results revealed that the incorporation of nitrogen in the MeOy matrix induces the production of films with electrical and optical responses rather different than the pure oxide that are strongly correlated with its structural arrangement, chemical composition an d morphology changes. On one hand the electrical resistivity and temperature coefficient of resistance were found to have a wide variation, which can be explained using a tunnel barrier conduction mechanism for the electric charge transport through the film, with possible applications in microelectronic devices. The particular morphology of the films induced a broadband optical response with high optical absorption from 290 to 2500 nm, with potential applications in solar cells and thermal photovoltaics.