Improved performance of TiN-diffusion barriers after a posttreatment

Summary form only given. The Ti/TiN barrier quality is improved by using posttreatments following the barrier layer deposition. The posttreatments were designed in order to stuff diffusion paths as well as to counteract barrier failure due to nonstoichiometric composition. Various TiN layers differing in stoichiometry were obtained by reactive sputtering in an Ar/N₂ mixture. Some of the barrier layers were posttreated by rapid thermal annealing in N₂. Film properties were analyzed by four-point-probe, XRD, AES, and TEM. Spiking tests were performed on wafers providing contact hole structures. These wafers underwent an aluminium metallization and were then annealed in the range of 450-600°C to provoke spiking. The results indicate that the posttreatments can improve the barrier quality. The main effects of the posttreatments are the formation of a fully nitrided layer close to the surface even for very N-deficient films and stuffing of the grain boundary diffusion paths