Film texture evolution in plasma treated TiN thin films

Abstract

In semiconductor technology, TiN thin film elements can be used as diffusion barrier between a metallic layer and a silicon oxide dielectric. Plasma application during the growth of TiN thin films modifies the microstructure of these films and consequently alters their physical properties. But details of the effect of plasma application on the evolution of the film microstructure and correlations between this evolution and the physical properties are still unclear. To clarify the correlations, the microstructure of a series of TiN thin films, deposited using an organometallic chemical vapor deposition technique combined with plasma treatments has been analyzed by transmission electron microscopy (TEM). The films were obtained by repeated fabrication sequences consisting of limited film growth followed by the application of a N2/H2 gaseous plasma with various powers and duration times and are actually stackings of plasma-treated elementary layers. TEM analysis shows that these films are made of nanocrystallites and that whereas crystallites are randomly oriented when no plasma is applied, short-time plasma treatments induce a tendency to 〈200〉 texture and longer treatments progressively rotate the direction of texture to 〈220〉.