Reaction barrier formation of W/poly-Si gate by NH3 rapid thermal annealing applicable to 0.15 μm CMOS devices

We found that an NH₃ rapid thermal annealing of Wi/poly-Si gate above 750°C resulted in the formation of a highly reliable in-situ barrier layer and low resistivity W, simultaneously. This barrier layer kept the Wi/poly-Si gate stable up to the elevated temperature of 1000°C. Ammonia treated W/poly-Si gate showed a narrow distribution of sheet resistance at a line width of 0.15 μm after the post annealing at 900°C for 30 min. This W/poly-Si gate was acceptable to apply to 0.15 μm CMOS devices without deposition of a barrier layer