ELECTRICAL CHARACTERIZATION OF REACTIVELY SPUTTERED TIN DIFFUSION BARRIER LAYERS FOR COPPER METALLIZATION

TiN films were characterized by sheet resistance measurements, Auger e lectron spectroscopy and cross-sectional transmission electron microsc opy. The properties as diffusion barrier between copper and silicon we re investigated by diode leakage current measurements on n(+)p diodes after annealing at 350 degrees C for 30 min and at 450, 500 and 550 de grees C for 60 min. Both Ti-rich and N-rich TiN films were deposited a t a DC magnetron power of 8 kW. Furthermore, additional N-rich films w ere deposited at a DC magnetron power of 2 kW. The copper was then dep osited by metalorganic low pressure chemical vapour deposition and by sputtering. Samples with and without a diffusion barrier were prepared . N-rich films deposited at DC magnetron powers of 2 and 8 kW are foun d to be an effective barrier up to an annealing at 500 degrees C for 6 0 min in case of metallization with sputtered copper. On the other han d the Ti-rich barriers still fail after annealing at 450 degrees C for 60 min. The barrier structures metallized with copper deposited by me talorganic low pressure chemical vapour deposition are almost broken e ven at lower temperatures.