STUDY OF TA(N,O) DIFFUSION BARRIER STABILITY - ANALYTICAL AND ELECTRICAL CHARACTERIZATION OF LOW-LEVEL CU CONTAMINATION IN SI

The diffusion barrier behaviour of 20 to 200 nm thin Ta(N,O) films in the Cu/Si contact system was evaluated by materials and transient ion drift analysis. Using high resolution transmission electron microscopy , grazing incidence X-ray diffractometry, Auger electron spectroscopy and secondary ion mass spectrometry depth profiling it was revealed th at the as-deposited amorphous-like Ta(N,O) diffusion barriers tend to partially recrystallize after annealing at 1 h/500 degrees C without a ny detectable diffusion and/or reaction of Cu and Si up to at least 1 h/600 degrees C. By making use of the newly developed transient ion dr ift technique for trace element analysis down to 5 x 10(11) cm(-3) of interstitially dissolved Cu in Si, an exponential decrease of the Cu c oncentration on the Ta(N,O) barrier thickness is observed.