Cu/poly-Si damascene gate structured MOSFET with Ta and TaN stacked barrier

摘要

A Cu/Si layered-gate-structured MOSFET with Ta and TaN stacked barrier layers fabricated using a Cu damascene process has been developed for high-performance and reliable Si ULSI devices. A sheet resistance of 0.5 ohm/sq. was achieved with a 0.25-μm gate length. The Ta and TaN layers guarantee reliable gate oxide (7.5 nm) after 500℃ thermal processing in nitrogen with forming gas annealing.