Effects of oxygen in TiNx on the diffusion of Cu in Cu/TiN/Al and Cu/TiNx/Si structures

Abstract

The role of oxygen has been found to be very significant in the diffusion of Cu in Cu/TiN_x/Al and Cu/TiN_xO_y/Al thin film structures. While no interdiffusion takes place in the Cu/TiN_xO_y/Al structure up to 575 °C, a substantial interdiffusion, with Cu and Al moving in opposite directions, has been found in the Cu/TiN_x/Al structure below 425 °C. Both Cu/TiN_x/Si and Cu/TiN_xO_y/Si systems have been found to be stable for temperatures below 600 °C, with TiN_x degrading before TiN_xO_y above this temperatures. Nuclear resonances, ¹⁶O(α,α)¹⁶O (3.052 MeV) and ¹⁴N(α,α)¹⁴N (3.593 MeV), for oxygen and nitrogen respectively, were used to determine the concentration of oxygen and the stoichiometry of the titanium nitride films.