Threshold voltage shift caused by copper contamination

High resolution Fowler-Nordheim field emission mapping, a relatively new technique that makes use of an atomic force microscope with a conducting tip (Ruskell et al., 1996), of thin thermal SiO/sub 2/ layers was used to investigate the yield and reliability implications of transistor scaling when trace amounts of copper contamination are present on the silicon surface prior to gate oxidation. A new failure mechanism is revealed that will start to manifest itself in 0.13 /spl mu/m technologies.