Barrier behaviour of plasma deposited silicon oxide and nitride against Cu diffusion

Various plasma deposited dielectric films have been studied for their stability against copper diffusion. The copper/dielectric interaction was characterized by Rutherford back scattering (RBS), Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) after stressing the samples thermally. Electrical measurements were performed on MIS structures to study the barrier properties of dielectrics. Therefore, I-V, I-t and C-V characteristics after different bias thermal stress (BTS) conditions were compared to those of unstressed Si/dielectric/Cu capacitors. All films investigated showed no interaction with copper during a heat treatment of 500°C for 1 h. However, if an electric field is applied simultaneously to the sample annealing the properties of silicon oxide degrades drastically while silicon oxynitrides and silicon nitride were much less influenced by BTS.